-
1.
The potential prolonged effect at one-year follow-up after 18-month randomized controlled trial of a 90 g/day low-carbohydrate diet in patients with type 2 diabetes.
Chen, CY, Huang, WS, Ho, MH, Chang, CH, Lee, LT, Chen, HS, Kang, YD, Chie, WC, Jan, CF, Wang, WD, et al
Nutrition & diabetes. 2022;12(1):17
-
-
-
Free full text
Plain language summary
A low carbohydrate diet (LCD) could be an effective dietary strategy for managing Type 2 Diabetes and body weight. This follow-up of a randomised controlled study evaluated the effect of moderate LCD after 18 months of 90 g/day LCD in 85 poorly controlled Type 2 Diabetic patients and compared it with Traditional Diabetic Diet (TDD). Those who followed the LCD diet ate significantly fewer carbohydrates and more protein and fat at the follow up between 18 and 30 months compared to those who followed the TDD group. The LCD group also showed significant improvements in serum HbA1C, two-hour serum glucose, serum alanine aminotransferase and Medication Effect Score in comparison with the TDD group. However, the level of triglycerides increased, and HDL levels decreased significantly in the LCD group from 18 to 30 months. There was however no significant difference between the groups in the improvement of HbA1C, fasting serum glucose, 2 h serum glucose, as well as serum cholesterol, triglycerides, low-density lipoprotein, ALT, creatinine, and urine microalbumin. To confirm the benefits of LCD on glycaemic control, further robust studies are needed. Results of this study can help healthcare professionals gain a better understanding of the prolonged effects of LCD on glycaemic control, liver function, and medication effect scores.
Abstract
OBJECTIVES To evaluate the effect at a one-year follow-up after an 18-month randomized controlled trial (RCT) of 90 gm/day low-carbohydrate diet (LCD) in type 2 diabetes. RESEARCH DESIGN AND METHODS Eighty-five poorly controlled type 2 diabetic patients with an initial HbA1c ≥ 7.5% who have completed an 18-month randomized controlled trial (RCT) on 90 g/day low-carbohydrate diet (LCD) were recruited and followed for one year. A three-day weighted food record, relevant laboratory tests, and medication effect score (MES) were obtained at the end of the previous trial and one year after for a total of 30 months period on specific diet. RESULTS 71 (83.5%) patients completed the study, 35 were in TDD group and 36 were in LCD group. Although the mean of percentage changes in daily carbohydrate intake was significantly lower for those in TDD group than those in LCD group (30.51 ± 11.06% vs. 55.16 ± 21.79%, p = 0.0455) in the period between 18 months and 30 months, patients in LCD group consumed significantly less amount of daily carbohydrate than patients in TDD group (131.8 ± 53.9 g vs. 195.1 ± 50.2 g, p < 0.001). The serum HbA1C, two-hour serum glucose, serum alanine aminotransferase (ALT), and MES were also significantly lower for the LCD group patients than those in the TDD group (p = 0.017, p < 0.001, p = 0.017, and p = 0.008 respectively). The mean of percentage changes of HbA1C, fasting serum glucose, 2 h serum glucose, as well as serum cholesterol, triglyceride, low-density lipoprotein, ALT, creatinine, and urine microalbumin, however, were not significantly different between the two groups (p > 0.05). CONCLUSIONS The one-year follow-up for patients on 90 g/d LCD showed potential prolonged and better outcome on glycaemic control, liver function and MES than those on TDD for poorly controlled diabetic patients.
-
2.
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
-
-
-
-
Free full text
Plain language summary
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:
-
X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
-
B: Systematic reviews including RCTs of limited number
-
C: Non-randomized trials, observational studies, narrative reviews
-
D: Case-reports, evidence-based clinical findings
-
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.
-
3.
Nutrition to Prevent or Treat Cognitive Impairment in Older Adults: A GRADE Recommendation.
Buckinx, F, Aubertin-Leheudre, M
The journal of prevention of Alzheimer's disease. 2021;8(1):110-116
-
-
-
Free full text
-
Plain language summary
Cognitive impairment is a public health problem due to its increasing prevalence in the aging population. Despite pharmacological advances, there are not yet effective treatments to delay or reverse cognitive impairment. Moreover, there is limited knowledge of Alzheimer disease modifiable risk factors namely nutrition. The aim of this review was to grade, classify and provide recommendations for the preferred diet to prevent or to treat cognitive impairment. This review shows that: - some nutritional factors appear to either increase the risk of cognitive decline or protect against it. - risk could be conferred by diets high in milk and dairy products whereas some protection can be offered by adhering to a Mediterranean diet to decrease the risk of cognitive decline. - it is important to follow a diet rich in mono- and poly- unsaturated fatty acids, fruit and vegetable, vitamin D and low in saturated fatty acids. Authors conclude that diet is an important modifiable factor to prevent or protect against cognitive decline.
Abstract
Aging is associated with cognitive declines leading to mild cognitive impairments or Alzheimer disease. Nutrition appear to protect from aging. Some dietary factors could either increase or protect against cognitive declines. This article aimed to provide GRADE recommendations related to nutrition aspects able to prevent or to treat cognitive impairments. A comprehensive literature review was performed using Medline database. The GRADE approach was used to classify quality of the existing evidence (systematic review or meta-analysis).The GRADE process led us to formulate seven key nutritional recommendations to manage cognitive declines, but did not allow us to do it for protein, vitamin B or antioxidants. Thus, 1) adherence to a Mediterranean diet (GRADE 1B); 2) high-level of consumption of mono- or poly- unsaturated fatty acids combined to a low consumption of saturated fatty acids (GRADE 1B); 3) high consumption of fruits and vegetables (GRADE 1B); 4) higher vitamin D intake (GRADE 1C) than the recommended daily allowance. In addition, a ketogenic diet, a low consumption of whole-fat dairy products or a caloric restriction are promising nutritional habits although the evidence does not yet support widespread uptake (GRADE 2C). In conclusion, nutrition is an important modifiable factor to prevent or protect against cognitive decline. Nevertheless, more studies are required to determine specific guidelines such as duration and amounts of nutrients to help older adult to maintain a healthy cognitive life.
-
4.
Sociodemographic and lifestyle-related risk factors for identifying vulnerable groups for type 2 diabetes: a narrative review with emphasis on data from Europe.
Kyrou, I, Tsigos, C, Mavrogianni, C, Cardon, G, Van Stappen, V, Latomme, J, Kivelä, J, Wikström, K, Tsochev, K, Nanasi, A, et al
BMC endocrine disorders. 2020;20(Suppl 1):134
-
-
-
Free full text
Plain language summary
Type 2 diabetes mellitus (T2DM) results from progressive loss of insulin secretion, which is typically combined with various degrees of insulin resistance. The aim of this study is to provide a comprehensive overview of key sociodemographic and lifestyle-related risk factors for identifying vulnerable groups for T2DM with emphasis on data from Europe. This study is a narrative review which includes 101 publications. Literature shows that prevention of T2DM should be a collaborative effort which mobilizes multiple partners/ stakeholders at a national and international (e.g. European) level. In addition, a holistic approach is becoming increasingly essential in order to put into effect multidimensional public health programs and integrated interventions for effective T2DM prevention which will take into account both traditional and socioeconomic/socioecological factors. Authors conclude that a multidimensional approach for the prevention of T2DM may have a broader impact against the current diabesity epidemic within and across countries in Europe.
Abstract
BACKGROUND Type 2 diabetes mellitus (T2DM) comprises the vast majority of all diabetes cases in adults, with alarmingly increasing prevalence over the past few decades worldwide. A particularly heavy healthcare burden of diabetes is noted in Europe, where 8.8% of the population aged 20-79 years is estimated to have diabetes according to the International Diabetes Federation. Multiple risk factors are implicated in the pathogenesis of T2DM with complex underlying interplay and intricate gene-environment interactions. Thus, intense research has been focused on studying the role of T2DM risk factors and on identifying vulnerable groups for T2DM in the general population which can then be targeted for prevention interventions. METHODS For this narrative review, we conducted a comprehensive search of the existing literature on T2DM risk factors, focusing on studies in adult cohorts from European countries which were published in English after January 2000. RESULTS Multiple lifestyle-related and sociodemographic factors were identified as related to high T2DM risk, including age, ethnicity, family history, low socioeconomic status, obesity, metabolic syndrome and each of its components, as well as certain unhealthy lifestyle behaviors. As Europe has an increasingly aging population, multiple migrant and ethnic minority groups and significant socioeconomic diversity both within and across different countries, this review focuses not only on modifiable T2DM risk factors, but also on the impact of pertinent demographic and socioeconomic factors. CONCLUSION In addition to other T2DM risk factors, low socioeconomic status can significantly increase the risk for prediabetes and T2DM, but is often overlooked. In multinational and multicultural regions such as Europe, a holistic approach, which will take into account both traditional and socioeconomic/socioecological factors, is becoming increasingly crucial in order to implement multidimensional public health programs and integrated community-based interventions for effective T2DM prevention.
-
5.
Immunomodulatory Effects of Diet and Nutrients in Systemic Lupus Erythematosus (SLE): A Systematic Review.
Islam, MA, Khandker, SS, Kotyla, PJ, Hassan, R
Frontiers in immunology. 2020;11:1477
-
-
-
Free full text
Plain language summary
Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by an abnormal inflammation affecting multiple organs, blood formation processes and the central nervous system. The condition is still not well understood and hence more specific and effective treatment options are lacking. How diet and lifestyle may play a role in the disease’s onset and development is still disputed, yet some nutritional aspects appear to be associated with SLE. This systematic review gathered clinical and preclinical evidence from animal and human studies, investigating dietary and nutritional interventions that either proved helpful in the management of SLE or had adverse effects. The review considered the impact of reduced calorie intake and body weight. It discussed the value of lower protein intake, in the context of SLE-related kidney complications and polyunsaturated fats such as omega-3 and olive oil and their role in regulating inflammatory pathways. Furthermore, it stressed the importance of fibre in gut health and immune regulation in SLE. The study also included evidence from Vitamin A, B, C, D and E, with particular detail on Vitamin D and its relation to disease prevention, progression and its immune regulatory capacity. Towards the end is a brief table displaying the more limited finding on some minerals, before exploring the plant-derived compound group of polyphenols and finally Royal jelly. In short, the authors suggested that moving towards a balanced diet can address unfavourable nutritional shortages commonly observed in SLE patients. A diet that is low in calories and protein but plentiful in fibre, polyunsaturated fats, vitamin A, B, C, D, and E, minerals and polyphenol-containing foods. Evidently, the components of such a diet have favourable effects on regulating inflammation and immune function and thus overall disease activity. This review affirms the importance of nutritional adequacy for the management of SLE.
Abstract
Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by multiple organ involvement, including the skin, joints, kidneys, lungs, central nervous system and the haematopoietic system, with a large number of complications. Despite years of study, the etiology of SLE remains unclear; thus, safe and specifically targeted therapies are lacking. In the last 20 years, researchers have explored the potential of nutritional factors on SLE and have suggested complementary treatment options through diet. This study systematically reviews and evaluates the clinical and preclinical scientific evidence of diet and dietary supplementation that either alleviate or exacerbate the symptoms of SLE. For this review, a systematic literature search was conducted using PubMed, Scopus and Google Scholar databases only for articles written in the English language. Based on the currently published literature, it was observed that a low-calorie and low-protein diet with high contents of fiber, polyunsaturated fatty acids, vitamins, minerals and polyphenols contain sufficient potential macronutrients and micronutrients to regulate the activity of the overall disease by modulating the inflammation and immune functions of SLE.
-
6.
Reduction in saturated fat intake for cardiovascular disease.
Hooper, L, Martin, N, Jimoh, OF, Kirk, C, Foster, E, Abdelhamid, AS
The Cochrane database of systematic reviews. 2020;5:CD011737
-
-
-
Free full text
-
Plain language summary
UK public health dietary advice focuses on reducing saturated fat intakes and replacing it with polyunsaturated and monounsaturated fats to prevent heart disease. This systematic review of 15 randomised control trials with approximately 59,000 participants aimed to compare the effect of reducing saturated fats and replacing it with polyunsaturated fats, monounsaturated fats, carbohydrate or protein on death or death due to heart disease. The results showed that reducing saturated fat intake for two years did not reduce death or death from heart disease but may have caused a 21% reduction in people suffering a heart attack, stroke or narrowing of the arteries in the arms or legs. Replacing saturated fat with polyunsaturated fat or carbohydrates probably reduces the risk of heart attack, stroke or narrowing of the arteries in the arms and legs, however, there were no effects on death. There was no evidence of any benefits in replacing saturated fat with protein. There was limited evidence on replacement of saturated fats with monounsaturated fats. Overall greater reductions in fat resulted in greater protection from heart disease. It was concluded that the evidence supports replacing saturated fat in the diet to reduce the risk of heart attack, stroke or narrowing of the arteries in the arms and legs, but this may not prevent death. This paper could be used by health care professionals to recommend a low saturated fat diet to reduce heart attack, stroke or narrowing of the arteries in individuals who are at risk or who have already suffered one of these events.
Abstract
BACKGROUND Reducing saturated fat reduces serum cholesterol, but effects on other intermediate outcomes may be less clear. Additionally, it is unclear whether the energy from saturated fats eliminated from the diet are more helpfully replaced by polyunsaturated fats, monounsaturated fats, carbohydrate or protein. OBJECTIVES To assess the effect of reducing saturated fat intake and replacing it with carbohydrate (CHO), polyunsaturated (PUFA), monounsaturated fat (MUFA) and/or protein on mortality and cardiovascular morbidity, using all available randomised clinical trials. SEARCH METHODS We updated our searches of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid) and Embase (Ovid) on 15 October 2019, and searched Clinicaltrials.gov and WHO International Clinical Trials Registry Platform (ICTRP) on 17 October 2019. SELECTION CRITERIA Included trials fulfilled the following criteria: 1) randomised; 2) intention to reduce saturated fat intake OR intention to alter dietary fats and achieving a reduction in saturated fat; 3) compared with higher saturated fat intake or usual diet; 4) not multifactorial; 5) in adult humans with or without cardiovascular disease (but not acutely ill, pregnant or breastfeeding); 6) intervention duration at least 24 months; 7) mortality or cardiovascular morbidity data available. DATA COLLECTION AND ANALYSIS Two review authors independently assessed inclusion, extracted study data and assessed risk of bias. We performed random-effects meta-analyses, meta-regression, subgrouping, sensitivity analyses, funnel plots and GRADE assessment. MAIN RESULTS We included 15 randomised controlled trials (RCTs) (16 comparisons, ~59,000 participants), that used a variety of interventions from providing all food to advice on reducing saturated fat. The included long-term trials suggested that reducing dietary saturated fat reduced the risk of combined cardiovascular events by 21% (risk ratio (RR) 0.79; 95% confidence interval (CI) 0.66 to 0.93, 11 trials, 53,300 participants of whom 8% had a cardiovascular event, I² = 65%, GRADE moderate-quality evidence). Meta-regression suggested that greater reductions in saturated fat (reflected in greater reductions in serum cholesterol) resulted in greater reductions in risk of CVD events, explaining most heterogeneity between trials. The number needed to treat for an additional beneficial outcome (NNTB) was 56 in primary prevention trials, so 56 people need to reduce their saturated fat intake for ~four years for one person to avoid experiencing a CVD event. In secondary prevention trials, the NNTB was 32. Subgrouping did not suggest significant differences between replacement of saturated fat calories with polyunsaturated fat or carbohydrate, and data on replacement with monounsaturated fat and protein was very limited. We found little or no effect of reducing saturated fat on all-cause mortality (RR 0.96; 95% CI 0.90 to 1.03; 11 trials, 55,858 participants) or cardiovascular mortality (RR 0.95; 95% CI 0.80 to 1.12, 10 trials, 53,421 participants), both with GRADE moderate-quality evidence. There was little or no effect of reducing saturated fats on non-fatal myocardial infarction (RR 0.97, 95% CI 0.87 to 1.07) or CHD mortality (RR 0.97, 95% CI 0.82 to 1.16, both low-quality evidence), but effects on total (fatal or non-fatal) myocardial infarction, stroke and CHD events (fatal or non-fatal) were all unclear as the evidence was of very low quality. There was little or no effect on cancer mortality, cancer diagnoses, diabetes diagnosis, HDL cholesterol, serum triglycerides or blood pressure, and small reductions in weight, serum total cholesterol, LDL cholesterol and BMI. There was no evidence of harmful effects of reducing saturated fat intakes. AUTHORS' CONCLUSIONS The findings of this updated review suggest that reducing saturated fat intake for at least two years causes a potentially important reduction in combined cardiovascular events. Replacing the energy from saturated fat with polyunsaturated fat or carbohydrate appear to be useful strategies, while effects of replacement with monounsaturated fat are unclear. The reduction in combined cardiovascular events resulting from reducing saturated fat did not alter by study duration, sex or baseline level of cardiovascular risk, but greater reduction in saturated fat caused greater reductions in cardiovascular events.
-
7.
Alternate Day Fasting Improves Physiological and Molecular Markers of Aging in Healthy, Non-obese Humans.
Stekovic, S, Hofer, SJ, Tripolt, N, Aon, MA, Royer, P, Pein, L, Stadler, JT, Pendl, T, Prietl, B, Url, J, et al
Cell metabolism. 2019;30(3):462-476.e6
-
-
-
-
Free full text
Plain language summary
Intermittent fasting and calorie restriction are believed to reduce cardiometabolic risk factors and increase longevity. Fasting alternate days (ADF) involves fasting for 36 hours and eating ad libitum for 12 hours. Thirty healthy participants were randomly assigned to a long-term ADF intervention group for ≥6 months against sixty participants in the control group. After completing the cross-sectional study arm, sixty healthy participants in the control group were randomly assigned to either a four-week short-term ADF intervention group or a control group with an ad libitum diet. Study participants adhered well to the fasting regimen. Both short-term and long-term ADF intervention groups showed a significant reduction in calorie intake, improvements in anthropometric and cardiovascular parameters including reduced BMI, substantial reduction in trunk fat, lower heart rate, increased serum β-hydroxybutyrate which is cardioprotective and anti-ageing, reduced circulating triiodothyronine (fT3) levels which indicate longevity. Short-term ADF reduced systolic and diastolic pressure, mean arterial pressure, pulse pressure, and pulse wave velocity. Long-term ADF intervention reduced circulating total cholesterol, low-density lipoprotein (LDL), very low-density lipoprotein (VLDL), and triglycerides, the age-related biomarker sICAM-1 for disease and inflammation, and improved lipid and amino acid metabolites. ADF did not affect insulin sensitivity. Although red blood cells and iron levels were altered, ADF interventions were not associated with iron deficiency. Healthcare professionals can use the results of this study to understand the cardioprotective and anti-ageing properties of ADF. However, further long-term robust studies are required to evaluate the effect of long-term ADF on bone health.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Short duration (<4 weeks) alternate day fasting may be an effective way to implement caloric restriction, improve body composition and reduce cardiovascular disease risk in healthy non-overweight adults.
- >6 months alternate fasting does not appear to be associated with reduced bone mass, bone mineral density of the lumbar spine region, white blood cell counts, ferritin and transferrin when compared to healthy controls.
- Both short term and long term alternate day fasting may reduce triiodothyronine in healthy adults. Low levels of fT3 without thyroid gland dysfunction has been associated with longevity in humans.
- Alternate day fasting should be performed alongside a trained clinician to reduce the risk of adverse effects due to critical medical conditions.
Evidence Category:
-
X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
-
B: Systematic reviews including RCTs of limited number
-
C: Non-randomized trials, observational studies, narrative reviews
-
D: Case-reports, evidence-based clinical findings
-
E: Opinion piece, other
Summary Review:
Introduction
Animal models have consistently demonstrated the healthspan and lifespan benefits of caloric restriction. However, chronic caloric restriction in humans has proven difficult to maintain.
Intermittent fasting may serve as a more manageable alternative to continuous caloric restriction. This randomised controlled trial and cross sectional analysis aimed to investigate the effects of alternate day fasting (ADF) on heart rate, blood pressure, cholesterol levels, CVD risk, body composition, and the metabolome and proteome of healthy, non-overweight adults (cohort median age between 48 and 52 years).
Methods
Prior to the enrollment of the study a cross sectional analysis was conducted on healthy adults engaged in long term (>6 months) alternate day fasting (n=30) and a control group (n=60).
The 60 participants from the cross sectional analysis control group were then randomised to either a 4 week ADF group or a control group. In both the >6 months and 4 weeks of ADF groups, participants were instructed to eat every second-day ad libitum, but to completely exclude solid and liquid foods and caloric beverages on fasting days.
Results
The cross sectional analysis identified that the alternate day fasting group:
- Consumed fewer calories vs the control group (−28.56%, p=0.0002).
- Had lower levels of circulating total cholesterol (p=0.004), LDL (p=0.011), VLDL (p=0.009), triglycerides (p=0.010) and a lower heart rate (p=0.040) vs the control group.
- Lower levels of soluble intercellular adhesion molecule-1 (sICAM-1) (p value 0.048), an age-associated inflammatory marker.
- Reduced circulating triiodothyronine (p<0.001) compared to the control group.
- In the metabolome, 54 out of 113 detected significantly modified metabolites (p value < 0.05) were at least 20% higher after 36 h of fasting, of which the majority (>95%) were lipids or free fatty acids, including polyunsaturated free fatty acids (PUFAs), α-tocopherol, and a type of vitamin E. 49 metabolites were at least 20% lower, consisting mainly (44.9%) of amino acids or related metabolites. Low levels of circulating amino acids have been found to increase lifespan in model organisms. The authors concluded that the elevation in fatty acids may be due to increased lipolysis from adipose tissue while the reduction in amino acids may be the result of increased gluconeogenesis.
- 13 out of 2,089 significantly (p value < 0.05) modulated protein hits within the PBMC proteome showed an increase of ≥15%, while the remaining proteins were downregulated after 36 h of fasting. Gene set enrichment analysis (GSEA) performed on the PBMC proteome unveiled changes in pathways related to lipid metabolism, pathways related to energy metabolism and stress response.
Following the 4 week intervention the alternate day fasting group demonstrated:
- Reduced caloric intake from baseline vs. the control group (−37.40% vs. −8.22%, p=0.0012).
- Greater reductions in body weight (−3.5kg vs −0.2kg, p<0.0001), BMI (−1.23kg/m2 vs −0.02kg/m2, p<0.0001) and improvements in their fat to lean mass ratio (−6.3% ± 5.0 percentage points, p value < 0.0001).
- Reduced systolic (−4.5mmHg, p=0.006) and diastolic (−2.5mmHg, p=0.03) blood pressure, heart rate (-4.5 b/min, p=0.0019), arterial (−3mmHg, p=0.0087) and pulse pressure (−2.5mmHg, p=0.0088) as well as pulse wave velocity (−1.538%, p=0.0362). Pulse wave velocity measures the rate at which pressure moves down the vessel wall and is a measure of arterial stiffness.
- Reduced circulating triiodothyronine (p<0.001) from baseline values.
Clinical practice applications:
The cross sectional analysis did not identify any differences in the long-term (>6 months) alternate day fasting group and control group in bone mass, bone mineral density of the lumbar spine region, white blood cell counts, ferritin and transferrin when compared to healthy controls. RBC counts and iron metabolism markers in the blood plasma (hematocrit, haemoglobin, iron, and transferrin saturation), were lower in the >6 months of ADF group but stayed within the reference range.
The randomised controlled trial demonstrated that alternate day fasting may be an effective intervention to reduce caloric intake, improve body composition and reduce cardiovascular disease risk in healthy non-overweight adults within 4 weeks.
Compliance rate was high with only 1 drop out in the alternate day fasting group of the randomised controlled trial.
Both the 4 week intervention and long-term (>6 month) analysis identified a reduction in triiodothyronine amongst the ADF groups. Low levels of triiodothyronine in absence of thyroid gland dysfunction has been associated with longevity in humans.
Considerations for future research:
- Future larger studies in non-healthy and/or overweight/obese populations would be useful to determine safety and efficacy of alternate day fasting within that population group.
- Further studies comparing alternate day fasting with continuous caloric restriction would be useful to identify which intervention is most beneficial for body composition and cardioprotection.
- Subgroup analysis of diet composition and diet quality may help to identify the most appropriate/inappropriate diet to compliment alternate day fasting.
- Longer duration randomised controlled trials are needed to identify any health risks or deficiencies which may develop with long term caloric restriction and alternate day fasting.
Abstract
Caloric restriction and intermittent fasting are known to prolong life- and healthspan in model organisms, while their effects on humans are less well studied. In a randomized controlled trial study (ClinicalTrials.gov identifier: NCT02673515), we show that 4 weeks of strict alternate day fasting (ADF) improved markers of general health in healthy, middle-aged humans while causing a 37% calorie reduction on average. No adverse effects occurred even after >6 months. ADF improved cardiovascular markers, reduced fat mass (particularly the trunk fat), improving the fat-to-lean ratio, and increased β-hydroxybutyrate, even on non-fasting days. On fasting days, the pro-aging amino-acid methionine, among others, was periodically depleted, while polyunsaturated fatty acids were elevated. We found reduced levels sICAM-1 (an age-associated inflammatory marker), low-density lipoprotein, and the metabolic regulator triiodothyronine after long-term ADF. These results shed light on the physiological impact of ADF and supports its safety. ADF could eventually become a clinically relevant intervention.
-
8.
A Mediterranean Diet with Fresh, Lean Pork Improves Processing Speed and Mood: Cognitive Findings from the MedPork Randomised Controlled Trial.
Wade, AT, Davis, CR, Dyer, KA, Hodgson, JM, Woodman, RJ, Keage, HAD, Murphy, KJ
Nutrients. 2019;11(7)
-
-
-
Free full text
Plain language summary
Dementia is characterised by severe cognitive impairment and reduced quality of life. Observational studies have demonstrated that populations following a traditional Mediterranean diet experience less cognitive decline and a lowered risk of dementia. The aim of this study was to examine a Mediterranean diet modified to include 2–3 fresh servings of pork each week across measures of cognitive function and well-being. The study is a 24-week parallel randomised controlled crossover design to compare a Mediterranean diet with 2-3 weekly servings of fresh, lean pork (MedPork) and a low-fat control diet (LF). It recruited adults aged 45–80 years due to their increased risk of developing cardiovascular disease. Results indicate that compared with the LF control diet, the MedPork intervention led to higher performance in the cognitive domain of processing speed and higher scores for the SF-36 subscale emotional role functioning. No significant differences were observed for other domains of cognitive function, nor for additional measures of psychological well-being. Authors conclude that the MedPork intervention can improve processing speed and mood in a population at risk of cardiovascular disease and therefore dementia.
Abstract
BACKGROUND The Mediterranean diet may be capable of improving cognitive function. However, the red meat restrictions of the diet could impact long-term adherence in Western populations. The current study therefore examined the cognitive effects of a Mediterranean diet with additional red meat. METHODS A 24-week parallel crossover design compared a Mediterranean diet with 2-3 weekly servings of fresh, lean pork (MedPork) and a low-fat (LF) control diet. Thirty-five participants aged between 45 and 80 years and at risk of cardiovascular disease followed each intervention for 8 weeks, separated by an 8-week washout period. Cognitive function was assessed using the Cambridge Neuropsychological Test Automated Battery. Psychological well-being was measured through the SF-36 Health Survey and mood was measured using the Profile of Mood States (POMS). RESULTS During the MedPork intervention, participants consumed an average of 3 weekly servings of fresh pork. Compared to LF, the MedPork intervention led to higher processing speed performance (p = 0.01) and emotional role functioning (p = 0.03). No other significant differences were observed between diets. CONCLUSION Our findings indicate that a Mediterranean diet inclusive of fresh, lean pork can be adhered to by an older non-Mediterranean population while leading to positive cognitive outcomes.
-
9.
Fat Quantity and Quality, as Part of a Low-Fat, Vegan Diet, Are Associated with Changes in Body Composition, Insulin Resistance, and Insulin Secretion. A 16-Week Randomized Controlled Trial.
Kahleova, H, Hlozkova, A, Fleeman, R, Fletcher, K, Holubkov, R, Barnard, ND
Nutrients. 2019;11(3)
-
-
-
Free full text
Plain language summary
Dietary macronutrients play an important role in the risk of obesity and type 2 diabetes. The aim of this study was to assess the effect of diet changes on body weight and metabolism. This study is a 16-week randomized clinical trial. Adult men and women, with a body-mass index between 28 and 40 kg/m2, were enrolled. Participants were randomly assigned to the vegan or the control group and examined at baseline and 16 weeks. Results show that: - in overweight individuals, both fat quantity and quality were associated with changes in body weight, body composition, insulin resistance and insulin secretion. - decreased intake of saturated, trans, or total fat was linked to decreased fat mass. - changes in the fatty acid composition of the diet were associated with changes in insulin resistance and insulin secretion. Authors conclude that selecting foods so as to limit the intake of saturated and trans fats and increase the relative content of polyunsaturated fatty acids, may be a useful strategy for metabolic health.
Abstract
Macronutrient composition of the diet influences the development of obesity and insulin resistance. The aim of this study was to assess the role of dietary fat quantity and fatty acid composition in body composition, insulin resistance, and insulin secretion. An open parallel randomized trial design was used. Overweight participants (n = 75) were randomized to follow a low-fat vegan (n = 38) or control diet (n = 37) for 16 weeks. Dual X-ray absorptiometry was used to measure body composition. Insulin resistance was assessed with the Homeostasis Model Assessment (HOMA-IR) index. Insulin secretion was assessed after stimulation with a liquid breakfast (Boost Plus, Nestle, Vevey, Switzerland). Self-reported 3-day diet records were used to assess dietary intake. A linear regression model was used to test the relationship between fat intake and body composition, insulin resistance, and insulin secretion. Changes in fat intake expressed as percent of total energy consumed correlated positively with changes in fat mass (r = 0.52; p < 0.001; and 0.347; p = 0.006, respectively), even after adjustment for changes in body-mass index (BMI) and energy intake (0.33; p = 0.01). Decreased intakes of C18:0 (r = 0.37, p = 0.004) and CLA-trans-10-cis12 (r = 0.40, p = 0.002), but increased intake of C18:2 (r = -0.40, p = 0.002) and C18:3 (p = -0.36, p = 0.006), were associated with a decrease in HOMA-IR, independent on changes in BMI and energy intake. The main fatty acids associated with changes in fasting insulin secretion were C12:0 (r = -0.31, p = 0.03), and TRANS 16:1 (r = -0.33, p = 0.02), both independent on changes in BMI and energy intake. Our findings demonstrate that, in the context of a low-fat vegan diet, decreased intake of saturated and trans fats and increased relative content of polyunsaturated fatty acids, particularly linoleic and α-linolenic acids, are associated with decreased fat mass and insulin resistance, and enhanced insulin secretion.
-
10.
Isocaloric Substitution of Dietary Carbohydrate Intake with Fat Intake and MRI-Determined Total Volumes of Visceral, Subcutaneous and Hepatic Fat Content in Middle-Aged Adults.
Meisinger, C, Rospleszcz, S, Wintermeyer, E, Lorbeer, R, Thorand, B, Bamberg, F, Peters, A, Schlett, CL, Linseisen, J
Nutrients. 2019;11(5)
-
-
-
Free full text
Plain language summary
Obesity, a worldwide epidemic due to the availability of many unhealthy food options and limited physical exercise, is a known risk factor for many metabolic disorders. The aim of this study was to investigate the association of carbohydrate intake and isocaloric substitution with different types of fat as determined by magnetic resonance imaging (MRI). The study’s analysis was based on the KORA-FF4 study, the second follow-up study of the KORA Survey S4. A total of 400 individuals participated in the FF4 study, from which 283 participants were included in this analysis. Results indicate an association between fat accumulation at specific anatomic locations and macronutrient composition among the participants. The isocaloric substitution of carbohydrates with fat was associated with higher hepatic (related to the liver) fat content and visceral fat accumulation. Authors conclude that the study’s findings can contribute towards the long-lasting discussion about a diet’s optimal fat content.
Abstract
The present study investigated the association of carbohydrate intake and isocaloric substitution with different types of fat with visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT) and hepatic fat content as determined by magnetic resonance imaging (MRI). Data from 283 participants (mean age 56.1 ± 9.0 years) from the MRI sub study of the KORA FF4 study were included. VAT, SAT and total body fat were quantified by a volume-interpolated VIBE-T1w-Dixon MR sequence. Hepatic fat content was determined as the proton density fat-fraction (PDFF) derived from multiecho-T1w MR sequence. Dietary intake was estimated using information provided by two different instruments, that is, repeated 24-h food lists and a food frequency questionnaire. Replacing total carbohydrates with an isoenergetic amount of total fat was significantly positively associated with VAT and hepatic fat, while there was no significant association with SAT. The multivariable adjusted β-coefficient for replacing 5% of total energy (5E%) carbohydrates with total fat was 0.42 L (95% CI: 0.04, 0.79) for VAT. A substitution in total fat intake by 5E% was associated with a significant increase in liver fat content by 23% (p-value 0.004). If reproduced in prospective studies, such findings would strongly argue for limiting dietary fat intake.