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Effect of Intermittent Fasting Diet on Glucose and Lipid Metabolism and Insulin Resistance in Patients with Impaired Glucose and Lipid Metabolism: A Systematic Review and Meta-Analysis.
Yuan, X, Wang, J, Yang, S, Gao, M, Cao, L, Li, X, Hong, D, Tian, S, Sun, C
International journal of endocrinology. 2022;2022:6999907
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The prevalence of obesity and metabolic syndrome may increase the risk of cardiovascular disease (CVD), diabetes, and neurological conditions. The imbalance in glucose and lipid metabolism and hypertension characterises the development of these chronic diseases. Intermittent fasting (IF) has been considered an effective dietary strategy for reducing the risk of obesity, insulin resistance, dyslipidaemia, diabetes, and CVD. This systematic review and meta-analysis include ten randomised controlled trials to evaluate the effects of IF intervention on glucose and lipid metabolism in people with metabolic syndrome. IF intervention regulated glucose metabolism by improving fasting blood glucose, glycosylated haemoglobin, insulin, and insulin resistance. IF intervention also positively impacted the body mass index and waist circumference. The total cholesterol, low-density lipoprotein levels, and triglyceride levels also improved, followed by the IF, showing the impact on lipid metabolism. Further robust studies are required due to heterogeneity between the included studies in type of IF, duration, the health status of participants, ethnicity, and outcome measurements. However, healthcare professionals can use the results of this systematic review and meta-analysis to understand the therapeutic effect of IF intervention on glycolipid metabolism in people with metabolic syndrome.
Expert Review
Conflicts of interest:
None
Take Home Message:
- IF does not require calorie restriction which may result in greater compliance
- IF does not restrict macronutrients such as CHO and fats, so may avoid the exclusion of key nutrients e.g. healthy fats and wholegrains.
- IF may have fewer adverse effects on daily routines and quality of life, which may mean adherence is easier.
- Improved glucose and lipid metabolism may prevent the development of chronic health conditions such as T2D, CVD and cancer.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Management of glucose and lipid metabolism can be achieved through weight reduction using dietary interventions such as very low calorie or CHO diets, which may be effective but difficult to sustain long term. An alternative approach for weight management, improved insulin resistance and subsequent prevention of comorbitities e.g. Type 2 Diabetes (T2D), Cardiovascular Disease (CVD) and cancer, is Intermittent Fasting (IF). such as time restricted or periodic fasting.
This study summarises the effects of IF dietary interventions lasting less than three months in overweight and obese women with Metabolic Syndrome, defined as the presence of any metabolic dysfunction including obesity, hyperglycaemia, dyslipidaemia or hypertension.
The meta-anlaysis was carried out following PRISMA guidelines. A literature search in PubMed and Medline using the keywords obesity/overweight, IF diet, metabolic syndrome, RCT’s and humans resulted in 10 studies with 12 types of intervention for analysis. The following outcomes were evaluated: glucose and lipid metabolism, insulin resistance, weight loss and blood pressure.
Results were analysed in R software using mean differences and 95% confidence intervals, and either random or fixed effects depending on the Cochrane’s Q and I(2) statistics. Funnel plots were inspected for potential bias and Egger’s regression tests for publication bias.
There were significant differences before and after the interventions for all glucose and lipid metabolism markers as well as body weight and systolic blood pressure :
Glucose metabolism:
- Fasting glucose reduced by 0.15mmol/L
- Insulin plasma reduced by 13.25uUI
- HbA1c reduced by 0.08%
- HOMA-IR (insulin resistance index) reduced by 0.31 on average
Lipid metabolism:
- Total cholesterol reduced by 0.32mmol/L
- LDL reduced by 0.22mmol/L
- Triglyceride reduced by 0.04mmol/L
Weight loss:
- Body weight reduced by 1.87kg
- BMI reduced by 0.8kg/m2
- Waist circumference reduced by 2.08cm
Blood pressure:
- Systolic reduced by 2.58mmHg
- Diastolic reduced by 3.12mmHg
Despite limitations of the meta-analysis, this study demonstrates IF has therapeutic effects on those with disordered lipid and glucose metabolism, and may prove to be an effective and sustainable approach.
Clinical practice applications:
- IF may be an effective alternative to restricted calorie or CHO diets for weight management with the associated benefits of glucose and lipid metabolism.
- IF has been shown to have therapeutic effects on individuals with impaired glucose and lipid metabolism.
- IF may be considered as a sustainable lifestyle choice rather than a ‘weight loss’ programme such as a very low calorie diet, which can result in poor quality of life and subsequent reduced adherence.
- Since it may take time for impaired glucose and lipid metabolism to progress to more serious disease states, establishing IF as an early intervention, may be considered as a prudent form of preventative medicine.
- IF has shown to have other health benefits such as reduced blood pressure and may be considered as adjuvant therapy.
Considerations for future research:
- Compares the effects of IF on different ethnicities, sex and age categories
- Evaluates the effect of IF on other disease states e.g. cancer, auto-immune conditions
- Assesses the response of other biomarkers e.g. inflammatory cytokines
- Compares different types and durations of IF on health biomarkers (eg periodic, time restricted)
Abstract
The question of whether or not intermittent fasting diets improve the clinical indicators of glycolipid metabolism remains unclear. This study systematically reviewed the relevant clinical trials to evaluate the effects of intermittent fasting diet on glucose and lipid metabolism and insulin sensitivity in patients with metabolic syndrome. To evaluate the effect of intermittent fasting diet intervention on patients with disorders of glucose and lipid metabolism, random-effect or fixed-effect meta-analysis models were used to calculate the average difference before and after intermittent fasting diet intervention and the corresponding 95% confidence intervals (CIs). After intermittent fasting diet intervention, in terms of glucose metabolism, fasting blood glucose reduced by 0.15 mmol/L (95% CI: -0.23; -0.06), glycosylated hemoglobin reduced by 0.08 (95% CIs: -0.25; -0.10), insulin plasma levels reduced by 13.25 uUI (95% CIs: -16.69; -9.82), and HOMA-IR decreased by 0.31 on an average (95% CIs: -0.44; -0.19). In addition, BMI decreased by 0.8 kg/m2 (95% CIs: -1.32; -0.28), body weight reduced by 1.87 kg (95% CIs: -2.67; -1.07), and the waist circumference decreased by 2.08 cm (95% CIs: -3.06; -1.10). Analysis of lipid metabolism showed that intermittent fasting diet intervention effectively reduced the total cholesterol level by 0.32 mmol/L (95% CIs: -0.60; -0.05), low-density lipoprotein level by 0.22 mmol/L (95% CIs: -0.37; -0.07), and triglyceride level by 0.04 mmol/L (95% CIs: -0.15; -0.07). Intermittent fasting diets have certain therapeutic effects on blood glucose and lipids in patients with metabolic syndrome and significantly improve insulin resistance. It may be considered as an auxiliary treatment to prevent the occurrence and development of chronic diseases.
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Dose-response relationship between weight loss and improvements in obstructive sleep apnea severity after a diet/lifestyle interventions: secondary analyses of the "MIMOSA" randomized clinical trial.
Georgoulis, M, Yiannakouris, N, Kechribari, I, Lamprou, K, Perraki, E, Vagiakis, E, Kontogianni, MD
Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine. 2022;18(5):1251-1261
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Obstructive sleep apnoea (OSA) represents one of the most common and serious sleep-related breathing disorders. Excess body weight has emerged as the strongest modifiable predictor of the onset and severity of OSA. The aim of this study was to explore the dose-response relationship between the degree of weight loss and improvements in OSA severity. This study is a secondary analysis of the Mediterranean diet/lifestyle Intervention for the Management of Obstructive Sleep Apnea (MIMOSA) study, which was designed as a single-centre, single-blind, parallel, randomised, controlled clinical trial. Results show that respiratory events and oximetry indices improved only in patients who lost weight and improvements were proportional to the degree of weight loss. Authors conclude that their findings indicate a dose-response relationship between the degree of weight loss and improvement in OSA severity and symptoms. However, further research is needed to gather more data on the optimal degree of weight loss and appropriate weight-loss interventions for managing the wide spectrum of OSA severity to guide clinical practice.
Expert Review
Conflicts of interest:
None
Take Home Message:
Important from a public health perspective:
- This study has confirmed that even a small degree of weight loss can have a beneficial effect on respiratory events and oxygen desaturation in moderate-to-severe OSA, but clinicians should preferably aim at a ≥ 5% weight loss, and ideally a ≥ 10% weight loss, to achieve clinically meaningful reductions in OSA severity.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
OSA represents one of the most common and serious sleep-related breathing disorders, with a high worldwide prevalence of almost 1 billion people. OSA has numerous well-established cardiometabolic consequences.
The authors highlight that weight loss is essential for obstructive sleep apnea (OSA) management. However, the optimal degree of weight loss for improving OSA severity or eliminating sleep-disordered breathing has not been extensively studied. The aim of this study was to explore the dose-response relationship between the degree of weight loss and improvements in OSA severity.
Methods
This is a secondary analysis of the Mediterranean diet/lifestyle Intervention for the Management of Obstructive Sleep Apnea (MIMOSA) study. This study was designed as a single-center, single-blind, parallel, randomised, controlled clinical trial to evaluate the effectiveness of a weight-loss Mediterranean dietary/lifestyle intervention on managing OSA.
This 6-month long clinical trial included 180 adult, overweight/obese moderate-to-severe OSA patients (45 patients per study group plus a 29% dropout rate). All patients were prescribed the standard of care continuous positive airway pressure (CPAP) therapy and were randomised to 3 arms: standard care; Mediterranean diet; Mediterranean lifestyle
Based on percent change in weight at 6 months, participants were categorised into a weight-stable/gain (WS/GG) group or one of 3 weight-loss groups (WLG): < 5%WLG; 5%–10%WLG; ≥ 10%WLG. Polysomnographic data and OSA symptoms were also evaluated preintervention and postintervention.
Results
Results confirm a dose-response relationship between the degree of weight loss achieved through a dietary/lifestyle intervention and improvements in OSA severity.
- Respiratory events and oximetry indices improved only in patients who lost weight. Improvements were proportional to the degree of weight loss.
- Median percent change in apnea-hypopnea index (AHI) was −11.7%, − 37.9%, and − 49.3% in the < 5%WLG, 5%–10%WLG, and ≥ 10%WLG, respectively (P < .001).
- Compared to the WS/GG, the age-, sex-, baseline-, and CPAP use–adjusted relative risk (95% confidence interval) of severe OSA (AHI ≥ 30 events/h) was 0.45 (0.23–0.87) in the 5%–10%WLG and 0.32 (0.17–0.64) in the ≥ 10%WLG; the risk was also lower in the ≥ 10%WLG vs the < 5%WLG (0.42 [0.22–0.82]).
- Insomnia and daytime sleepiness also improved more in participants exhibiting ≥ 5% weight loss.
- The dose-response relationship between weight loss and improvement in OSA severity was evident regardless of self-reported CPAP use.
Conclusions
The authors conclude that even a < 5% weight loss was sufficient for improvements in respiratory events and oximetry indices, but the prevalence of severe OSA reduced only after a ≥ 5% weight loss, and patients achieving a ≥ 10% weight loss exhibited the greatest benefits compared to weight-stable/gain patients.
Clinical practice applications:
These findings might be useful for Nutritional Therapists and Clinical Practitioners:
- Clinicians should aim for a ≥ 5% weight loss, and ideally a ≥ 10% weight loss, to achieve clinically meaningful reductions in OSA severity.
- Improvements after weight loss were significant even though a healthy body weight was not achieved.
Considerations for future research:
- The study sample consisted of predominantly male, overweight, otherwise healthy patients with moderate-to-severe OSA. Therefore, findings cannot be generalised to the whole OSA population and further research is required with broader, diverse, study samples.
- 6 months is a short duration period, therefore longer trials are required.
- Self-reported CPAP use by participants is a limitation of this study. Further robust analysis methods should be considered for future trials.
- Participants were advised to abstain from CPAP therapy for 2 days prior to the follow-up PSG but this was not evaluated or confirmed in this study and should be in future research.
Abstract
STUDY OBJECTIVES Lifestyle-induced weight loss is a complementary therapeutic approach for obstructive sleep apnea (OSA). We aimed at identifying the dose-response relationship between weight loss and OSA severity improvement. METHODS This is a secondary analysis of a 6-month clinical trial in 180 adult, overweight/obese moderate-to-severe OSA patients. Participants were randomized to a standard care, a Mediterranean diet, or a Mediterranean lifestyle arm. All patients were prescribed with continuous positive airway pressure (CPAP), while intervention arms additionally participated in a weight-loss dietary/lifestyle intervention. Based on percent change in weight at 6 months, participants were categorized into a weight-stable/gain (WS/GG) group or 3 weight-loss groups (WLG): < 5%WLG, 5%-10%WLG, and ≥ 10%WLG. Polysomnographic data and OSA symptoms were evaluated preintervention and postintervention. RESULTS Respiratory events and oximetry indices improved only in patients who lost weight and improvements were proportional to the degree of weight loss. Median percent change in apnea-hypopnea index (AHI) was -11.7%, - 37.9%, and - 49.3% in the < 5%WLG, 5%-10%WLG, and ≥ 10%WLG, respectively (P < .001). Compared to the WS/GG, the age-, sex-, baseline-, and CPAP use-adjusted relative risk (95% confidence interval) of severe OSA (AHI ≥ 30 events/h) was 0.45 (0.23-0.87) in the 5%-10%WLG and 0.32 (0.17-0.64) in the ≥ 10%WLG; the risk was also lower in the ≥ 10%WLG vs the < 5%WLG (0.42 [0.22-0.82]). Insomnia and daytime sleepiness also improved more in participants exhibiting ≥ 5% weight loss. CONCLUSIONS Even a < 5% weight loss can reduce respiratory events, but a ≥ 5% and ideally ≥ 10% weight loss is necessary for reducing the prevalence of severe OSA. CLINICAL TRIAL REGISTRATION Registry: ClinicalTrials.gov; Name: Mediterranean Diet/Lifestyle Intervention in Obstructive Sleep Apnea; URL: https://clinicaltrials.gov/ct2/show/NCT02515357; Identifier: NCT02515357. CITATION Georgoulis M, Yiannakouris N, Kechribari I, et al. Dose-response relationship between weight loss and improvements in obstructive sleep apnea severity after a diet/lifestyle intervention: secondary analyses of the "MIMOSA" randomized clinical trial. J Clin Sleep Med. 2022;18(5):1251-1261.
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Enhancing Night and Day Circadian Contrast through Sleep Education in Prediabetes and Type 2 Diabetes Mellitus: A Randomized Controlled Trial.
García-Serrano, C, Pujol Salud, J, Aran-Solé, L, Sol, J, Ortiz-Congost, S, Artigues-Barberà, E, Ortega-Bravo, M
Biology. 2022;11(6)
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Diabetes mellitus is a chronic condition that occurs when blood glucose levels increase because the body cannot produce enough insulin or cannot effectively use the insulin it produces. Type 2 diabetes mellitus (T2DM) is the most common type of diabetes. It is a chronic metabolic disease that can be controlled when its pathophysiological factors are neutralised. The aim of this study was to analyse the effect of a sleep hygiene intervention in the management of impaired fasting glucose (IFG) and T2DM. This is an experimental study based on a parallel clinical trial using blocked randomization with equal allocation ratio. A total of 69 participants were included in the analysis (31 and 38 from the control and intervention groups, respectively). Results show a significant improvement in all the measured sleep parameters (sleep quality, time and efficiency). Furthermore, it also demonstrates that sleep health educational intervention, delivered during the regular check-ups of patients with T2DM or IFG, has a positive metabolic effect and is feasible as a complementary therapy in primary care settings. Authors conclude that sleep education improves T2DM metabolic management.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Sleep has a restorative function that benefits glucose metabolism.
- Sleep education should emphasise that maintaining a regular and sufficient sleep schedule and establishing a series of routines and habits in the hours prior to going to sleep would prevent early awakenings.
- Education is an important part of clinical practice.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
The aim of this study was to analyse the effect of a sleep hygiene intervention in the management of impaired fasting glucose (IFG) or type 2 diabetes mellitus (T2DM).
Methods
This experimental parallel open-label clinical trial included 69 adults with IFG or T2DM.
The intervention was individual informative education which aimed to develop skills to improve sleep, which consisted of:
1. Information: Reading of the educational sheet (9 tips for a healthy sleep) with subsequent discussion.
2. Verification: checking participants understood the advice.
3. Participant information: One telephone call after 1 month was made as educational reinforcement of the intervention.
The controlled group received no educational intervention. The main outcome variable measured was levels of HbA1c (%) 3 and 6 months post intervention. Secondary outcomes were fasting glucose (mg/dL) 3 and 6 months post intervention, Pittsburgh Sleep Quality Index (PSQI), declared sleep hours and sleeping efficiency 3 months post intervention.
Results
- . 84.2% participants from the intervention group and 14.0% in the control group reported a change in sleep habits.
- 3 months after the intervention, the control group did not report any change, while the intervention group reported a statistically significant improvement in all three: PSQI (−2.97 ± 2.93), hours of sleep (1.00 [0.00; 2.00] hours) and sleep efficiency (6.74 ± 12.9%).
- The intervention group achieved a significant reduction in 3 months post intervention fasting glucose levels (−14.69; CI 95%: −28.15, −1.22) and HbA1c levels (−0.39; 95% CI: −0.73, −0.05), as well as a reduction in 6 months post intervention HbA1c levels (−0.66; 95% CI: −0.96, −0.36).
Conclusion
- The results show a significant improvement in all the measured sleep parameters (sleep quality, time and efficiency).
- The PSQI score improvement in the intervention group was 3.6 points higher than the control group.
- The median sleep time in the intervention group was increased by 1.5 h, doubling the number of participants who reported sleeping more than 6 h.
Clinical practice applications:
- An educational intervention in sleep hygiene and circadian contrast may help to increase sleep quality, time and efficiency.
- The educational intervention helped lower HbA1c levels in patients with IFG and T2DM.
- Sleep education helps to improve T2DM metabolic management.
- The 9 tips for a healthy sleep, were developed from the latest guidelines from the American Academy of Sleep Medicine, the National Health Service, and the Health Department of Catalonia.
Considerations for future research:
- The open-labelled intervention and the use of subjective variables related to sleep quality could lead to biassed self-reports in the intervention group so further studies are required.
- Future studies should gather baseline parameters closer to the start of the intervention rather than wait 3 months to assess the immediate outcomes of the intervention.
- Future research could take the same approach with diet and exercise education.
Abstract
BACKGROUND Evidence supports a causal relationship between circadian disturbance and impaired glucose homeostasis. METHODS To determine the effect of an educational intervention delivered by primary care nurses to improve sleep hygiene, a parallel, open-label clinical trial in subjects aged 18 and older with impaired fasting glucose (IFG) or type 2 diabetes mellitus (T2DM) was performed. Study variables were sex, age, fasting glucose, glycated haemoglobin A1c (HbA1c), Pittsburgh Sleep Quality Index (PSQI), sleep duration and efficiency, body mass index, antidiabetic treatment, diet and physical exercise. An individual informative educational intervention was carried out following a bidirectional feedback method. The intervention aimed to develop skills to improve sleep through nine simple tips. An analysis of covariance was performed on all the mean centred outcome variables controlling for the respective baseline scores. RESULTS In the intervention group, PSQI dropped, the duration and quality of sleep increased, and a decrease in fasting glucose and in HbA1c levels was observed. CONCLUSION The proposed intervention is effective for improving sleep quality, length and efficiency, and for decreasing fasting glucose and HbA1c levels in only 3 months. These findings support the importance of sleep and circadian rhythm education focused on improving IFG and T2DM.
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Longitudinal association of dietary carbohydrate quality with visceral fat deposition and other adiposity indicators.
Zamanillo-Campos, R, Chaplin, A, Romaguera, D, Abete, I, Salas-Salvadó, J, Martín, V, Estruch, R, Vidal, J, Ruiz-Canela, M, Babio, N, et al
Clinical nutrition (Edinburgh, Scotland). 2022;41(10):2264-2274
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Abdominal obesity, measured by waist circumference, a proxy of visceral fat, is increasing at an even greater rate than overall obesity alone. Diet plays a key role in body fat accumulation; however, recent evidence also indicates that, beyond quantity, the quality of certain nutrients may have an independent effect. The aim of this study was to determine the dynamic association between changes in overall dietary carbohydrate quality and changes in objectively measured visceral and overall adiposity distribution This study is a prospective cohort study based on data collected during the first year of the PREDIMED-Plus (PREvencion con DIeta MEDiterranea Plus) randomised controlled trial. In the PREDIMED-Plus trial, a total of 6874 people were randomly allocated in a 1:1 ratio to either the intervention or control group. Results show that a carbohydrate quality index increase was associated with a decrease in regional and overall adiposity. The observed associations were mostly driven by fibre and the wholegrains/total grains ratio. Authors conclude that the promotion of fibre-rich foods, including fruits, vegetables, legumes and nuts, and the substitution of refined grains by wholegrains, may be important dietary recommendations to adopt in clinical practice to promote a healthier body composition.
Expert Review
Conflicts of interest:
None
Take Home Message:
This prospective cohort of older adults with overweight/obesity and MetS, found that improvements in dietary carbohydrate quality over one year was associated with positive changes in visceral and overall fat deposition, largely due to dietary fibre and the wholegrain/total grain ratio.
Evidence Category:
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A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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X
C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Background
Obesity prevalence is increasing worldwide and is associated with a range of metabolic and cardiovascular diseases. Excess visceral fat appears with increasing age but also with unhealthy dietary patterns and lifestyle behaviours, and it contributes to chronic diseases, particularly type 2 diabetes (T2D), insulin resistance, metabolic syndrome (MetS), and cardiovascular diseases (CVD).
Aim
This study determined the association between changes in overall dietary carbohydrate quality and changes in objectively-measured visceral and overall adiposity distribution. Three repeated measurements of diet and adiposity were conducted throughout a 1-year follow-up, using a dual-energy X-ray absorptiometry (DXA) scans for body composition assessment.
The study compared an intensive weight-loss (intervention group) using an energy-reduced Mediterranean Diet (MedDiet), with physical activity (PA), and behavioural support on the prevention of CVD events, compared to usual care and dietary counselling only.
This prospective cohort study analysed a subgroup of 1476 participants (men aged 55-75 years and women aged 60-75 years) enrolled in the PREDIMED-Plus randomized controlled trial. Participants were overweight or obese (BMI>27 kg/m2 and <40 kg/m2) with no previous cardiovascular events and at least three characteristics of metabolic syndrome (MetS): hypertension, hyper-triglyceridemia, lower high-density lipoprotein (HDL) cholesterol, hyperglycemia, or central obesity.
Dietary intake was measured at baseline, 6- and 12-months using a Spanish version of the validated 143-item semi-quantitative food-frequency questionnaire, via face-to-face interviews by trained dietitian-nutritionists. Carbohydrate quality index (CQI) was calculated using four criteria: total dietary fibre, glycemic index, wholegrain/total grain carbohydrate ratio, and solid/total carbohydrate ratio.
Results
Improvements in body composition and lifestyle factors were observed compared to baseline data (both study arms combined) (p < 0.05 for all). A higher Carbohydrate Quality Index CQI (p = 0.024) was observed at both the 6 and 12 month follow-up.
A 3-point increment in CQI over 12-month follow-up was associated with a decrease in visceral fat (β 0.067 z-score, 95% CI -0.088 to -0.046, p<0.001), android-to-gynoid fat ratio* (β -0.038, 95% CI -0.059 to -0.017, p<0.001) (*calculated by dividing the fat mass (g) from the specific regions), and total fat (β -0.064, 95% CI -0.080 to -0.047, p<0.001).
Fibre intake and the ratio of whole grain/total grain showed the strongest inverse associations with all adiposity indicators. Statistically significant differences were observed over time in all CQI components. The most relevant changes were the increase in consumption of carbohydrates from whole-grains and a decrease in refined grains, and an increase in dietary fibre intake. After evaluating each CQI component separately, the study found that fibre intake and the ratio of whole grain/total grain presented the strongest and statistically significant negative associations with all adiposity indicators (all p-values <0.01).
Limitations
Due to the observational nature of the study, causality cannot be inferred. The study population is based on older people with overweight/obesity and MetS from a Mediterranean area, which can limit the generalisability of findings to the general population.
The use of self-reported dietary data is subject to measurement error, where self-reports may be affected by a tendency to respond in a manner to avoid criticism or judgement and to seek social approval.
Clinical practice applications:
Evidence has shown that the quality of dietary carbohydrates, rather than the quantity, may have a greater impact on health and overall mortality.
While visceral fat constitutes only a small proportion of total fat, the available evidence indicates that it plays an important role in certain chronic diseases, such as T2D, MetS, CVD and cancer.
Findings from this study suggest a better CQI via the manipulation of carbohydrate quality may be associated with a decrease in visceral fat, which are independent of changes in total body fat.
Considerations for future research:
Future strategies to decrease visceral fat are warranted.
Robust reference ranges are needed for the interpretation of visceral fat in clinical practice and research settings.
Abstract
BACKGROUND & AIMS The quality of dietary carbohydrates rather than total carbohydrate intake may determine the accumulation of visceral fat; however, to date, few studies have examined the impact of diet on adiposity using specific imaging techniques. Thus, the aim of this prospective study was to investigate the association between concurrent changes in carbohydrate quality index (CQI) and objectively-quantified adiposity distribution over a year. METHODS We analyzed a cohort of 1476 participants aged 55-75 years with overweight/obesity and metabolic syndrome (MetS) from the PREDIMED-Plus randomized controlled trial. Dietary intake information was obtained at baseline, 6- and 12-months from a validated 143-item semi-quantitative food-frequency questionnaire, and CQI (range: 4 to 20) was calculated based on four dietary criteria: total dietary fibre, glycemic index, wholegrain/total grain carbohydrate ratio, and solid/total carbohydrate ratio. Overall and regional adiposity (total body fat, visceral fat and android-to-gynoid fat ratio) was quantified using dual-energy X-ray absorptiometry at all three time points. Multiple adjusted linear mixed-effects models were used to assess associations between concurrent changes in repeatedly measured CQI and adiposity over time. RESULTS After controlling for potential confounding factors, a 3-point increment in CQI over 12-month follow-up was associated with a decrease in visceral fat (β -0.067 z-score, 95% CI -0.088; -0.046, p < 0.001), android-to-gynoid fat ratio (-0.038, -0.059; -0.017, p < 0.001), and total fat (-0.064, -0.080; -0.047, p < 0.001). Fibre intake and the ratio of wholegrain/total grain showed the strongest inverse associations with all adiposity indicators. CONCLUSIONS In this prospective cohort of older adults with overweight/obesity and MetS, we found that improvements in dietary carbohydrate quality over a year were associated with concurrent favorable changes in visceral and overall fat deposition. These associations were mostly driven by dietary fibre and the wholegrain/total grain ratio. TRIAL REGISTRATION The trial was registered at the International Standard Randomized. CONTROLLED TRIAL (ISRCTN http://www.isrctn.com/ISRCTN89898870) with number 89898870 and registration date of 24 July 2014, retrospectively registered.
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A Randomized Controlled Trial of Fasting and Lifestyle Modification in Patients with Metabolic Syndrome: Effects on Patient-Reported Outcomes.
Jeitler, M, Lauche, R, Hohmann, C, Choi, KA, Schneider, N, Steckhan, N, Rathjens, F, Anheyer, D, Paul, A, von Scheidt, C, et al
Nutrients. 2022;14(17)
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The metabolic syndrome (MetS) is a condition characterized by the presence of at least three cardiovascular risk factors, such as abdominal obesity, hypertension, insulin resistance, and dyslipidaemia. The aim of this study was to assess effects of fasting followed by the Mind-Body Medicine in Integrative and Complementary Medicine (MICOM) lifestyle modification intervention in patients with MetS on patient-reported outcomes, compared to a lifestyle modification intervention only. This study is a single-blind, bicentre, randomized controlled study. Patients (n=145) were randomly assigned in a 1:1 ratio into one of the 2 groups: fasting and lifestyle modification or the lifestyle modification. They started with 2 vegan days (max. 1200 kcal/day), followed by 5 days of fasting (max. 350 kcal/day), and a stepwise reintroduction of food. Then they participated in the 10-week MICOM comprehensive multimodal lifestyle modification intervention with weekly 6-h sessions. Results show that after the multimodal lifestyle modification intervention, there were improvements for all outcome measures, namely quality of life, anxiety, depression, stress, mood as well as self-efficacy, mindfulness, and self-compassion, which persisted at the follow-up after 24 weeks. Authors conclude that their findings show beneficial and clinically relevant effects of fasting and intensified lifestyle modification on quality of life and psychological parameters.
Expert Review
Conflicts of interest:
None
Take Home Message:
For clients with Metabolic syndrome a 5-day fast consisting of max. 350 kcal/day, in conjunction with therapies that focus on improved emotional, mental, social, spiritual, and behavioural factors may directly affect health and support improved mood.
Therapies include mindfulness and specific group training rooted in psycho-neuroendocrinology, and the use of formal meditation and gentle yoga exercises. As well as nutritional education included lectures, cooking workshops, as well as group support.
Bottom line: The use of complimentary therapies such as mindfulness, yoga and medication in conjunction with nutritional advice and may be effective to support improved mood in clients with Metabolic syndrome.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Metabolic syndrome (MetS) is a condition characterised by the presence of at least three cardiovascular risk factors such as abdominal obesity, hypertension, insulin resistance, and dyslipidemia.
The authors refer to epidemiological studies that have identified the role of psychological risk factors such as psychosocial stress, depression and anxiety in patients with MetS and cardiovascular disease.
This single-blind, bi-centre RCT assessed the effects of fasting followed by a comprehensive lifestyle modification program MICOM (Mind-Body Medicine in Integrative and Complementary Medicine) in 145 participants with Metabolic Syndrome (MetS) (62.8% women; 59.7 ± 9.3 years) randomised to:
1. 5-day fasting followed by 10 weeks of lifestyle modification (F + LM; modified DASH diet, exercise, mindfulness; n = 73) or
2. 10 weeks of lifestyle modification only (LM; n = 72)
The study duration was 24 weeks occurring from April 2014 to December 2014, with the last follow-up assessment in December 2015. 73 Participants were randomised into an F + LM group and 72 participants into an LM group between the ages of 59 and 60.
Outcomes were assessed at weeks 0, 1, 12, and 24, for quality of life (Short-Form 36 Health Survey Questionnaire, SF-36), anxiety/depression (Hospital Anxiety and Depression Scale, HADS), stress (Cohen Perceived Stress Scale, CPSS), mood (Profile of Mood States, POMS), self-efficacy (General Self-Efficacy Scale, GSE), mindfulness (Mindfulness Attention Awareness Scale, MAAS), and self-compassion (Self-Compassion Scale, SCS).
At week 1, POMS depression and fatigue scores were significantly lower in F + LM compared to LM. At week 12, most self-report outcomes improved in both groups—only POMS vigour was significantly higher in F + LM than in LM. Most of the beneficial effects within the groups persisted at week 24.
Clinical practice applications:
This randomised controlled trial highlights fasting-induced mood-modulating effects in the short term (<24 months).
LM induced several positive effects on quality of life and psychological parameters in participants with MetS.
The compliance rate for this study was good and there were no adverse effects reported suggesting a potentially effective lifestyle modification intervention for adults with metabolic syndrome.
The authors did note the extent to which participants adhered to the program by using stress reduction techniques at home was not assessed.
Considerations for future research:
MBM lifestyle modification intervention led to an improvement of self-efficacy, mindfulness, and self-compassion.
Further studies to explore explanatory models for the effects of MBM are needed.
Mediating variables on mindfulness, self-efficacy, and compassion, and the effects on physical and psychological parameters, need to be examined more closely.
Future studies could use condition-specific questionnaires in addition to generic ones, which have previously been used to facilitate the comparison of the study results with those in the population.
Abstract
Lifestyle interventions can have a positive impact on quality of life and psychological parameters in patients with metabolic syndrome (MetS). In this randomized controlled trial, 145 participants with MetS (62.8% women; 59.7 ± 9.3 years) were randomized to (1) 5-day fasting followed by 10 weeks of lifestyle modification (F + LM; modified DASH diet, exercise, mindfulness; n = 73) or (2) 10 weeks of lifestyle modification only (LM; n = 72). Outcomes were assessed at weeks 0, 1, 12, and 24, and included quality of life (Short-Form 36 Health Survey Questionnaire, SF-36), anxiety/depression (Hospital Anxiety and Depression Scale, HADS), stress (Cohen Perceived Stress Scale, CPSS), mood (Profile of Mood States, POMS), self-efficacy (General Self-Efficacy Scale, GSE), mindfulness (Mindfulness Attention Awareness Scale, MAAS), and self-compassion (Self-Compassion Scale, SCS). At week 1, POMS depression and fatigue scores were significantly lower in F + LM compared to LM. At week 12, most self-report outcomes improved in both groups-only POMS vigor was significantly higher in F + LM than in LM. Most of the beneficial effects within the groups persisted at week 24. Fasting can induce mood-modulating effects in the short term. LM induced several positive effects on quality of life and psychological parameters in patients with MetS.
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6.
The effect of high-polyphenol Mediterranean diet on visceral adiposity: the DIRECT PLUS randomized controlled trial.
Zelicha, H, Kloting, N, Kaplan, A, Yaskolka Meir, A, Rinott, E, Tsaban, G, Chassidim, Y, Bluher, M, Ceglarek, U, Isermann, B, et al
BMC medicine. 2022;20(1):327
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Visceral adipose tissue (VAT) accumulation is one of the main key factors that differentiate between metabolic healthy and unhealthy obese individuals. VAT is closely related to the development of multiple cardiovascular risk factors. The Mediterranean (MED) diet, high in polyphenol content and rich in plant food sources, was shown to have an enhanced effect on VAT reduction in combination with physical activity (PA), regardless of weight loss The aim of this study was to assess the effect of the MED diet, further enriched with polyphenols, and lower in red and processed meat (“green-MED diet”) on visceral adiposity in the 18-month Dietary Intervention Randomized Controlled Trial-Polyphenols, Unprocessed trial. This study is a randomised controlled trial. Participants were randomly assigned to one of three intervention groups (1:1:1 ratio): healthy dietary guidelines, MED diet, or green-MED diet, all included PA recommendations, with a free gym membership and educational sessions promoting moderate-intensity PA. Results show that participants following the green-MED diet achieved more than twice the degree of VAT reduction compared to those following the MED diet, despite similar weight loss. In fact, VAT loss was specifically related to lower red meat intake and increased walnuts, green tea, Wolfa globosa, and dietary fibre (this was reflected by higher plasma polyphenol and serum folate levels). Authors conclude that a green-MED diet enriched with polyphenols and decreased red meat consumption might serve as an improved version of the MED diet for targeted VAT reduction.
Expert Review
Conflicts of interest:
None
Take Home Message:
- The positive health effects of the traditional MED diet, moderately high in PUFAs and MUFAs and low in red meat, are well-established
- Higher levels of total plasma polyphenol and serum folate may reflect higher consumption of “green” dietary components, which were significantly associated with greater VAT loss
- The green-MED diet, richer in dietary polyphenols and green plant-based proteins and lower in red meat, might be a more effective strategy for VAT loss than the traditional healthy MED diet, achieving more than twice the degree of VAT reduction, despite similar weight loss.
- VAT loss was specifically related to lower red meat intake and increased walnuts, green tea, Wolffia globosa, and dietary fibre and was reflected by higher plasma polyphenol and serum folate levels.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
A mediterranean (MED) diet is a rich source of polyphenols, which benefit adiposity by several mechanisms. Visceral adipose tissue (VAT) accumulation is one of the main factors that differentiate between metabolic healthy and unhealthy obese individuals.
In this Dietary Intervention Randomised Controlled Trial PoLyphenols UnproceSsed (DIRECT‐ PLUS) weight‐loss trial, 294 participants were randomised to: (A) healthy dietary guidelines (HDG), (B) MED, or (C) green‐MED diets, all combined with physical activity. The study duration was 18‐months.
This study explored the effect of the green‐MED diet, twice fortified in dietary polyphenols and lower in red/processed meat, on visceral adipose tissue (VAT) and used magnetic resonance imaging (MRI) to quantify the abdominal adipose tissues.
Both isocaloric (with the same calorific value) MED groups consumed 28 g/day of walnuts (+ 440 mg/day polyphenols). The green‐MED group further consumed green tea (3–4 cups/day) and Wolffia globosa (duckweed strain) plant green shake (100 g frozen cubes/day) (+ 800mg/day polyphenols) and reduced red meat intake.
The mean weight loss (HDG: −0.4% (5.0), MED: −2.7% (5.6), green-MED: −3.9% (6.5)) and WC loss (HDG: −3.6% (5.1), MED: −4.7% (5.0), green-MED: −5.7%(5.7)) after 18 months were similar between the two MED diets (p > 0.05 for all) and higher as compared to the HDG (weight: HDG vs. MED: p = 0.02; HDG vs. green+MED: p < 0.001; WC: HDG vs. MED: p = 0.33, HDG vs. green+MED: p = 0.02).
All three abdominal fat depots decreased over 18 months of intervention (p < 0.05 vs. baseline for all). The green-MED group achieved a greater reduction in VAT than the other intervention groups (HDG: −4.2% (22.5), MED: −6.0%(31.3), green-MED: −14.1%(27.7); p < 0.05 green-MED vs. MED or vs. HDG groups). These differences in VAT loss across the groups remained significant after adjusting for age, sex, and 18-month WC change (green-MED vs. MED p = 0.023; green-MED vs. HDG p = 0.002) (Fig. 1)
Limitations of the study included a low proportion of women, and different VAT proportions at baseline across groups limit the generalisability of findings to women.
The authors of the study did not identify the exact components responsible for the dietary effects when they compared dietary regimens and not specific nutrients.
Adherence was by a validated, self-reported dietary intake assessment tool, which the authors acknowledge is subject to error
Strengths of the study included the relatively large sample size, high retention rate, and use of 3-T MRI measurements (considered one of the gold standards tools for the quantification of specific fat depots
Clinical practice applications:
- This trial shows that, when combined with a Mediterranean diet, higher dietary consumption of green tea, walnuts, and dietary fibre and reduced red meat consumption were significantly associated with greater %VAT loss
- The authors observed a significant synergistic interaction effect between decreased red meat consumption and increased serum folate on VAT loss
- A reduction in VAT accumulation, known as a key risk factor in CVD development, may reduce metabolic complications, improve the lipid profile, and decrease cardiometabolic risk.
Considerations for future research:
- Future studies are needed to explore the exact mechanisms of specific polyphenol-rich foods on visceral adiposity.
- Future studies could explore whether the results are replicable in both male and female participants, as this sample was largely male.
Abstract
BACKGROUND Mediterranean (MED) diet is a rich source of polyphenols, which benefit adiposity by several mechanisms. We explored the effect of the green-MED diet, twice fortified in dietary polyphenols and lower in red/processed meat, on visceral adipose tissue (VAT). METHODS In the 18-month Dietary Intervention Randomized Controlled Trial PoLyphenols UnproceSsed (DIRECT-PLUS) weight-loss trial, 294 participants were randomized to (A) healthy dietary guidelines (HDG), (B) MED, or (C) green-MED diets, all combined with physical activity. Both isocaloric MED groups consumed 28 g/day of walnuts (+ 440 mg/day polyphenols). The green-MED group further consumed green tea (3-4 cups/day) and Wolffia globosa (duckweed strain) plant green shake (100 g frozen cubes/day) (+ 800mg/day polyphenols) and reduced red meat intake. We used magnetic resonance imaging (MRI) to quantify the abdominal adipose tissues. RESULTS Participants (age = 51 years; 88% men; body mass index = 31.2 kg/m2; 29% VAT) had an 89.8% retention rate and 79.3% completed eligible MRIs. While both MED diets reached similar moderate weight (MED: - 2.7%, green-MED: - 3.9%) and waist circumference (MED: - 4.7%, green-MED: - 5.7%) loss, the green-MED dieters doubled the VAT loss (HDG: - 4.2%, MED: - 6.0%, green-MED: - 14.1%; p < 0.05, independent of age, sex, waist circumference, or weight loss). Higher dietary consumption of green tea, walnuts, and Wolffia globosa; lower red meat intake; higher total plasma polyphenols (mainly hippuric acid), and elevated urine urolithin A polyphenol were significantly related to greater VAT loss (p < 0.05, multivariate models). CONCLUSIONS A green-MED diet, enriched with plant-based polyphenols and lower in red/processed meat, may be a potent intervention to promote visceral adiposity regression. TRIAL REGISTRATION ClinicalTrials.gov , NCT03020186.
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7.
Lipid Intake and Breast Cancer Risk: Is There a Link? A New Focus and Meta-Analysis.
Lodi, M, Kiehl, A, Qu, FL, Gabriele, V, Tomasetto, C, Mathelin, C
European journal of breast health. 2022;18(2):108-126
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Incidence of breast cancer is the leading cause of cancer-related mortality, accounting for 15.5% of all cancer-related deaths. However, there is a lack of complete understanding of the effects of different types of dietary lipids on breast cancer development, such as saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), dietary cholesterol, polyunsaturated fatty acids (PUFA), and unsaturated trans fatty acids (TFA). An evaluation of the effect of lipid consumption on breast cancer and the impact it has on menopausal status was conducted in this meta-analysis, which included forty-four studies. Increased saturated fatty acid intake was associated with an increased risk of breast cancer in postmenopausal women. However, breast cancer risk was not associated with increased consumption of total fat, SFA, MUFA, PUFA, and cholesterol in premenopausal women. The effects of estrogen and the release of proinflammatory cytokines by adipocytes should be evaluated, as well as other pathways that contribute to the development of breast cancer. There is a need for further robust studies to evaluate the effects of different types of lipid consumption on breast cancer. Although the association between SFA and breast cancer is weak, healthcare professionals can use this study's findings to better understand the detrimental effect of SFA, despite the fact that there is a great deal of heterogeneity in the current analysis.
Expert Review
Conflicts of interest:
None
Take Home Message:
- The authors found no association between total fat, saturated fatty-acids, mono and poly-unsaturated fatty acids and cholesterol intake and breast cancer incidence in the general population and in pre-menopausal women.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
- Among lifestyle-related breast cancer risk factors, the role of diet in breast cancer remains uncertain.
- The authors highlight a weak association between high SFA consumption and breast cancer risk in post-menopausal women.
- The authors found no association between total fat, saturated fatty-acids, mono and poly-unsaturated fatty acids and cholesterol intake and breast cancer incidence in the general population and in pre-menopausal women.
Objectives
- To determine if there is an association between total lipid intake, saturated fatty acid (SFA), Poly- and Mono-Unsaturated Fatty Acid (PUFA and MUFA) and cholesterol intake and breast cancer risk.
Results
- Forty-four articles were included in the meta-analysis, consisting of 28 case-control studies and 16 cohort studies.
- In total, this meta-analysis involved 1,185,896 women, of whom 54,553 had breast cancer.
- There was no association between total fat, SFA, MUFA, PUFA and cholesterol intake and breast cancer in the general population and in pre-menopausal women.
- In postmenopausal women, high SFA consumption was associated with increased breast cancer risk in case-control studies [relative risk (RR): 1.12; confidence interval (CI) 95%: 1.03–1.21; p = 0.006 but not in cohort studies (RR: 1.01; CI 95%: 0.85–1.19; p = 0.93).
Limitations
- Studies included in the meta-analysis were carried out on populations from five continents with significant cultural and dietary diversity, and well as different types of oils used in the diet
Conclusion
- At this stage, the authors state it is not possible to establish nutritional recommendations regarding the consumption of lipids to decrease breast cancer risk.
Clinical practice applications:
- The results of this meta-analysis does not demonstrate a statistically significant link between high consumption of total lipids, PUFA, MUFA and cholesterol and the occurrence of breast cancer.
- However, the results suggest that there is an association between SFA intake and breast cancer risk in postmenopausal women, although this was only found in case-controlled studies and not cohort studies.
- While obesity is a known breast cancer risk factor after menopause, the link between the effect of diet and the effect of obesity on the breast may be through different mechanisms.
- The authors investigated if high lipid consumption acts on breast tissue by the same mechanisms as obesity, and found the association between SFA intake and breast cancer risk in postmenopausal women must be through other biological explanations.
- The authors found that while high SFA consumption may increase breast cancer risk among post-menopausal women, biological mechanisms linking SFA and breast cancerogenesis are still unknown.
- The meta-analysis found high blood cholesterol levels appear to increase the risk of breast cancer. However, the authors could not confirm that high dietary cholesterol intake is a risk factor for breast cancer. The authors postulated this may be in part due to the low proportion of cholesterol (about 30%) in the diet, while the rest comes from the degradation of lipids and carbohydrates by the liver.
Considerations for future research:
- As lipids can have different actions in the same family, studies should rather focus on specific lipid consumption
Abstract
Objective: To determine if there is an association between total lipid intake, saturated fatty acid (SFA), Poly- and Mono-Unsaturated Fatty Acid (PUFA and MUFA) and cholesterol intake and breast cancer risk. Materials and Methods: We conducted a systematic review of the literature and a meta-analysis following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We included all cohort and case-control studies published up to December 2020 with subgroup analysis according to menopausal status. Results: We included 44 articles for analysis. There was no association between total fat, SFA, MUFA, PUFA and cholesterol intake and breast cancer in the general population and in pre-menopausal women. In postmenopausal women, high SFA consumption was associated with increased breast cancer risk in case-control studies [relative risk (RR): 1.12; confidence interval (CI) 95%: 1.03-1.21; p = 0.006 but not in cohort studies (RR: 1.01; CI 95%: 0.85-1.19; p = 0.93). Conclusion: There was a weak association between high SFA consumption and breast cancer risk in post-menopausal women, however there was high heterogeneity for this analysis. As lipids can have different actions in the same family, studies should rather focus on specific lipid consumption.
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8.
Enriched Marine Oil Supplement Increases Specific Plasma Specialized Pro-Resolving Mediators in Adults with Obesity.
Al-Shaer, AE, Regan, J, Buddenbaum, N, Tharwani, S, Drawdy, C, Behee, M, Sergin, S, Fenton, JI, Maddipati, KR, Kane, S, et al
The Journal of nutrition. 2022;152(7):1783-1791
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Specialised pro-resolving mediators (SPMs) are highly potent oxylipins [metabolites] synthesized from omega-3 and omega-6 polyunsaturated fatty acids. SPMs have a critical role in resolving inflammation and returning damaged tissues to homeostasis. The main aim of this study was to determine if a marine oil supplement increased specific metabolites of the SPM biosynthetic pathway in adults with obesity. This study is a non-randomised uncontrolled clinical trial in adults with obesity. Twenty-three participants (n = 13 females, 10 males) aged between 50–65 years were enrolled. Only postmenopausal females were included in order to reduce confounding effects of oestrogen on lipid metabolism during supplementation. Results show that: - the marine oil supplement significantly increased some oxylipins of the SPM biosynthetic pathway. - there wasn’t an increase in the concentration of D-series resolvins upon intervention, although several docosahexaenoic acid-derived metabolites were increased. - the supplement decreased some HETEs [metabolites], which are synthesized from arachidonic acid. Authors conclude that their findings provide a framework for futures studies on the use of a marine oil supplement to examine the effects of how SPMs and their metabolic intermediates control varying aspects of inflammation and immunity, including antibody concentrations, in subjects with obesity.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Marine oil enriched with specialised pro-resolving mediators raise levels of EPA, DPA and DHA-metabolites in adult subjects with obesity
- Larger randomised, blinded and placebo-controlled trials are required to inform healthcare practitioner clinical practice decisions relating to SPM enriched marine oil supplementation
- Future research is required to determine if increased concentrations of SPMs control the resolution of inflammation in humans with obesity.
Evidence Category:
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A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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X
C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
- Specialised pro-resolving mediators (SPMs) are oxylipins synthesised from omega-3 and -6 PUFAs which play a role in resolving inflammation.
- The authors highlight mouse studies have found that increasing the levels of SPMs and their metabolic intermediates can improve a range of obesity related complications. Thus, there is scientific interest in increasing the levels of SPMs in humans with diseases associated with chronic inflammation, such as obesity.
- This small non-randomised uncontrolled clinical trial of 23 individuals (13 female; 10 male) aged 50-65 years with obesity (BMI 30-40), aimed to determine the impacts of 1 month supplementation with marine oil particularly enriched with 14-hydroxydocosahexanenoic acid (14-HDHA), 17-HDHA and 18-hydroxydocosahenaenoic acid (HEPE) on:
- The change in levels of PUFA-derived oxylipins from baseline
- The change in abundance of circulating peripheral blood mononuclear cells (PBMCs)
- The change in antibody production
Intervention
- 2g enriched marine oil (4 capsules of SPM Active provided by Metagenics, study sponsor) once daily for 28-30 consecutive days.
Inclusion/Exclusion Criteria
- Only post-menopausal women were included to reduce confounding effects of oestrogen on lipid metabolism
- Individuals were excluded if diagnosed with Type 1 or 2 diabetes, autoimmunity, liver disease, coagulopathy, uncontrolled hypothyroid or active malignancy
- Individuals were excluded if they consumed omega-3 PUFA supplements within 3 months of intervention, regularly consumed >2 servings per week of fatty fish, had a fish/shellfish allergy or were taking a predetermined list of medications.
Findings
- Statistically significant increases were found in certain EPA, DPA and DHA-derived metabolites in response to supplementation relative to baseline. However, only 17-HDHA concentrations increased relative to baseline, with no effect on 14-HDHA or 18-HEPE, despite the supplement being enriched with all 3 metabolites
- Statistically significant decreases were found in arachidonic acid (AA)-derived oxylipins post supplementation relative to baseline
- Increases in immune cell populations in circulation did not reach significance post supplementation when measured by PBMCs.
Conclusions
An enriched marine oil supplement increased select SPMs in adults with obesity.
Clinical practice applications:
- Healthcare practitioners working with adults with obesity can use the results from this trial to understand that 1 month supplementation with 4g of enriched marine oil supplementation raises levels of certain EPA, DPA and DHA metabolites
- Practitioners may want to follow the research in this area as larger, controlled trials are conducted and comparisons made with non-enriched fatty acid supplements.
Considerations for future research:
- Future clinical studies of SPM supplementation are required that are double-blind, randomised and placebo-controlled to inform scientific findings in this area
- This study was inadequately powered to assess differences between female and male participants and therefore larger trials are needed to inform the sex differences in oxylipins within the population with obesity
- Further research is required in younger subjects with obesity to assess SPMs as a possible chronic inflammation preventative strategy, due to inflammation complications over time
- Future research should take account of the heterogeneity in the population with obesity, such as microbiome profiles, food intake and baseline metabolic status
- Further studies comparing impacts of standard marine oil with enriched marine oil on chronic inflammation would inform healthcare practitioners in their clinical practice.
Abstract
BACKGROUND Specialized pro-resolving mediators (SPMs), synthesized from PUFAs, resolve inflammation and return damaged tissue to homeostasis. Thus, increasing metabolites of the SPM biosynthetic pathway may have potential health benefits for select clinical populations, such as subjects with obesity who display dysregulation of SPM metabolism. However, the concentrations of SPMs and their metabolic intermediates in humans with obesity remains unclear. OBJECTIVES The primary objective of this study was to determine if a marine oil supplement increased specific metabolites of the SPM biosynthetic pathway in adults with obesity. The second objective was to determine if the supplement changed the relative abundance of key immune cell populations. Finally, given the critical role of antibodies in inflammation, we determined if ex vivo CD19 + B-cell antibody production was modified by marine oil intervention. METHODS Twenty-three subjects [median age: 56 y; BMI (in kg/m2): 33.1] consumed 2 g/d of a marine oil supplement for 28-30 d. The supplement was particularly enriched with 18-hydroxyeicosapentaenoic (HEPE), 14-hydroxydocosahexaenoic acid (14-HDHA), and 17-HDHA. Blood was collected pre- and postsupplementation for plasma mass spectrometry oxylipin and fatty acid analyses, flow cytometry, and B-cell isolation. Paired t-tests and Wilcoxon tests were used for statistical analyses. RESULTS Relative to preintervention, the supplement increased 6 different HEPEs and HDHAs accompanied by changes in plasma PUFAs. Resolvin E1 and docosapentaenoic acid-derived maresin 1 concentrations were increased 3.5- and 4.7-fold upon intervention, respectively. The supplement did not increase the concentration of D-series resolvins and had no effect on the abundance of immune cells. Ex vivo B-cell IgG but not IgM concentrations were lowered postsupplementation. CONCLUSIONS A marine oil supplement increased select SPMs and their metabolic intermediates in adults with obesity. Additional studies are needed to determine if increased concentrations of specific SPMs control the resolution of inflammation in humans with obesity. This trial was registered at clinicaltrials.gov as NCT04701138.
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9.
Intake and adequacy of the vegan diet. A systematic review of the evidence.
Bakaloudi, DR, Halloran, A, Rippin, HL, Oikonomidou, AC, Dardavesis, TI, Williams, J, Wickramasinghe, K, Breda, J, Chourdakis, M
Clinical nutrition (Edinburgh, Scotland). 2021;40(5):3503-3521
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This systematic review investigated vegan diets in the European populations and their adequacy of macro-and micronutrient intake, compared to the recommendations of the World Health Organization. Included were 48 studies and their outcomes regarding protein, carbohydrates, fats and micronutrients summarized. The overall results and their impact on health are discussed in the later sections of the paper. Adequate intake amongst vegans was seen with carbohydrates, fats, Vitamin A, B1, В6, C, E, iron, phosphorus, magnesium, copper and folate. Sodium exceeded recommended intake, whilst protein, Vitamin B2, B3, B12, D, iodine, zinc, calcium, potassium, selenium was of low consumption in a vegan diet. The bioavailability of some nutrients was also acknowledged. In summary, following a vegan diet appears to have positive and negative aspects. A vegan diet profile can contribute to disease prevention with lower incidence rates of obesity, Type 2 diabetes, and cardiovascular disease. Yet veganism appears to increase the risk for mental health conditions, bone fractures, immune system impairments, anaemias and deficiencies from low nutrient intake. This review yields a comprehensive overview of the positive and negative health consequences of a vegan diet. It may be a useful reference for those looking to support vegans or individuals considering adopting a vegan diet pattern.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Vegan diets in European populations tend to be lower in protein intake, particularly amino acids lysine, methionine and tryptophan.
- Other micronutrients that tend to lower in vegan diets are Vitamin B12, zinc, calcium and selenium.
- Healthcare practitioners should be aware of these potential deficiencies when working with vegan clients.
Evidence Category:
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A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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X
B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Vegan diets have become increasingly popular in the last ten years. This systematic review of 48 studies investigated the adequacy of vegan diets in European populations. It compared their macro- and micronutrient intakes compared to World Health Organization recommendations. It found that vegan diets tend to be lower in protein and in essential amino acids (lysine, methionine and tryptophan). They can also be lower in micronutrients especially vitamin B12, zinc, calcium and selenium. However, the lower intakes are not always associated with health impairments.
Clinical practice applications:
Practitioners should be aware of the potential deficiencies in a vegan diet.
Considerations for future research:
More research is needed to determine whether lower nutrient intakes in vegans correlated with poor health outcomes.
Abstract
BACKGROUND Vegan diets, where animal- and all their by-products are excluded from the diet, have gained popularity, especially in the last decade. However, the evaluation of this type of diet has not been well addressed in the scientific literature. This study aimed to investigate the adequacy of vegan diets in European populations and of their macro- and micronutrient intakes compared to World Health Organization recommendations. METHODS A systematic search in PubMed, Web of Science, IBSS, Cochrane library and Google Scholar was conducted and 48 studies (12 cohorts and 36 cross-sectional) were included. RESULTS Regarding macronutrients, vegan diets are lower in protein intake compared with all other diet types. Veganism is also associated with low intake of vitamins B2, Niacin (B3), B12, D, iodine, zinc, calcium, potassium, selenium. Vitamin B12 intake among vegans is significantly lower (0.24-0.49 μg, recommendations are 2.4 μg) and calcium intake in the majority of vegans was below recommendations (750 mg/d). No significant differences in fat intake were observed. Vegan diets are not related to deficiencies in vitamins A, B1, Β6, C, E, iron, phosphorus, magnesium, copper and folate and have a low glycemic load. CONCLUSIONS Following a vegan diet may result in deficiencies in micronutrients (vitamin B12, zinc, calcium and selenium) which should not be disregarded. However, low micro- and macronutrient intakes are not always associated with health impairments. Individuals who consume a vegan diet should be aware of the risk of potential dietary deficiencies.
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10.
Effect of sleep duration on dietary intake, desire to eat, measures of food intake and metabolic hormones: A systematic review of clinical trials.
Soltanieh, S, Solgi, S, Ansari, M, Santos, HO, Abbasi, B
Clinical nutrition ESPEN. 2021;45:55-65
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Adequate sleep is crucial to health. Yet, sleep disturbances have become very common in modern societies. A lack of sleep is linked to increased risk for several chronic diseases such as diabetes, high blood pressure, metabolic syndrome and cardiovascular disease. Furthermore, appetite-regulating hormones can be disrupted by sleep shortages, which is thought to drive chronic overeating, leading to weight gain, obesity and its associated health consequences. This review examined the relationship between sleep duration and food consumption and energy intake, whilst also monitoring changes in body weight and appetite-regulating hormones. The review encompassed 50 randomized controlled trials (RCTs) with 3387 participants, including 1079 children and adolescents and 2308 adults. The findings suggested that sleep shortages contribute to significant increases in calorie intake, fat intake, increased body weight, appetite, hunger, more frequent eating and bigger portion sizes. In this review lack of sleep did not change protein and carbohydrate intake. Nor did lack of sleep make people exert more or less energy overall, however, a variance amongst ethnic groups was observed here. There was not enough evidence for changes in metabolic rate, so the review assumed no significant effect. When viewed collectively, the appetite-regulating hormones of leptin and ghrelin, the stress hormone cortisol and the sugar-regulating hormone insulin were not significantly influenced by sleep duration. However, there seemed to be a wide variance of outcomes when looking at individual studies' results. In conclusion, the authors reiterated the importance of sleep for health maintenance, advocating for a minimum of 7 hours of sleep per day for adults and that, despite busy modern lifestyles, sleep optimisation strategies should be prioritised. Less than 6 hours of sleep per day increases the risk of health consequences, like weight gain and metabolic disorders and sleep management should be considered part of their treatment protocols.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Reduced sleep duration may serve as a mediator for weight gain in part due to increased appetite, increased fat intake and disruptions to energy balance.
- Enhancing sleep quality may serve to support weight loss protocols.
Evidence Category:
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A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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X
B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
Short sleep duration and disruptions to circadian rhythm have been associated with being overweight and obese. It has been suggested that sleep restriction may interfere with appetite regulating hormones leading to increased appetite and disrupted energy balance.
This study aimed to systematically review studies exploring the relationship between sleep duration and food consumption, energy intake, anthropometric characteristics and appetite-regulating hormones.
Methods
This systematic review included 50 randomised controlled trials including 3,387 participants.
Results
Energy intake
- 13 out of 30 the included studies found that short sleep conditions led to higher energy intake.
- 1 study identified that sleep restriction resulted in a 15.3% and 9.2% increase in energy intake in both women and men.
- 3 studies noted that prolonging sleep duration led to a reduction in energy intake.
- 1 study reported a reduction in energy intake after sleep restriction (P=0.031).
Fat consumption
- 9 studies out of 22 identified a significant association between short sleep and increased fat consumption.
- 7 studies did not identify a difference between groups.
- 3 studies noted a decrease in fat consumption following prolonged sleep (P<0.001, P<0.05, P=0.04).
Hunger and appetite
- 11 studies out of 17 observed that sleep restriction resulted in increased hunger ratings.
- 3 studies found an increase in appetite following sleep restriction (P<0.01) with 3 finding no difference..
- 1 study reported a decrease in appetite following sleep restriction.
- 2 studies noted that portion sizes increased as a result of sleep restriction (P<0.01).
- 1 study reported an increase in eating occasions following restricted sleep compared to habitual sleep (6.08 vs 4.96).
Body weight
- 6 studies out of 14 found no effect of sleep loss on body weight.
- 4 studies identified that sleep restriction led to weight gain (P<0.001, P<0.05, P=0.14, P=0.031).
- 2 studies reported weight loss following increased sleep duration (P<0.001).
Ghrelin and leptin
- Leptin and ghrelin levels were generally not found to be influenced by sleep duration, with the exception of a few studies.
Clinical practice applications:
Reduced sleep duration may promote weight gain by:
- Increasing energy intake.
- Increasing fat consumption.
- Increasing hunger and appetite.
- Increasing portion sizes and eating occasions.
Prolonging sleep duration may support weight loss by:
- Reducing energy intake.
- Reducing fat intake.
Considerations for future research:
- Mixed results on the influence of sleep restriction on appetite regulating hormones, leptin and ghrelin.
- Some studies noted the negative impact of sleep restriction on leptin and ghrelin concentrations, collectively shortened sleep duration did not appear to influence these hormones.
- Further sleep restriction studies exploring additional appetite regulating hormones and neuropeptides and the reward system may provide a more definitive understanding of the underlying mechanism for reduced sleep duration to disrupt the appetite and energy balance and promote weight gain.
Abstract
BACKGROUND AND AIMS Sleep, as well as diet and physical activity, plays a significant role in growth, maturation, health, and regulation of energy homeostasis. Recently, there is increasing evidence indicating a possible causal association between sleep duration and energy balance. We aimed to examine the relationship between sleep duration and food consumption, energy intake, anthropometric characteristics, and appetite-regulating hormones by randomized controlled trials (RCTs). METHODS Electronic literature searches were conducted on Medline, Web of Science, and Google Scholar until July 2020. The search was conducted with the following words: "Sleep Duration", "Circadian Rhythm", "Sleep Disorders" in combination with "Obesity", "Overweight", "Abdominal Obesity", "Physical Activity", "Energy Intake", "Body Mass Index", "Lipid Metabolism", "Caloric Restriction", Leptin, "Weight Gain", and "Appetite Regulation" using human studies.methods RESULTS After screening 708 abstracts, 50 RCTs (7 on children or adolescents and 43 on adults) were identified and met the inclusion criteria. In general, the findings suggested that sleep restriction may leads to a significant increment in energy intake, fat intake, body weight, appetite, hunger, eating occasions, and portion size, while protein and carbohydrate consumption, total energy expenditure, and respiratory quotient remained unaffected as a result of sleep restriction. Serum leptin, ghrelin, and cortisol concentrations were not influenced by sleep duration as well. CONCLUSION Insufficient sleep can be considered as a contributing factor for energy imbalance, weight gain, and metabolic disorders and it is suggested that to tackle disordered eating it may be necessary to pay more attention to sleep duration.