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1.
Distribution of energy intake across the day and weight loss: A systematic review and meta-analysis.
Young, IE, Poobalan, A, Steinbeck, K, O'Connor, HT, Parker, HM
Obesity reviews : an official journal of the International Association for the Study of Obesity. 2023;24(3):e13537
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Obesity increases an individual's risk of metabolic disease, such as diabetes and cardiovascular disease, musculoskeletal disorders such as osteoarthritis, and some cancers. “Chrononutrition” relates to the timing of meals and distribution of total energy intake across the day. Evidence is building chrononutrition as a potential target in both weight loss and metabolic disease interventions. The aim of this study was to examine the impact of earlier versus later distribution of total daily energy intake on weight loss, and to evaluate the potential for utilizing altered energy distribution as a tool in weight loss interventions. This study is a systematic review and meta-analysis of nine clinical studies. Total number of participants was 485 (earlier distributed total energy intakes: n = 244, later distributed total energy intakes; n = 241). Results show that energy intakes with a focus on earlier distribution resulted in significantly greater weight loss when compared with similarly energy-restricted diets with individuals consuming a larger proportion of their total energy intake later in the day and into the evening. Authors conclude that earlier energy intakes may be a promising tool to be used in conjunction with other weight loss strategies such as energy restriction to enhance weight loss. However, further research is required to elucidate the additional positive impacts that earlier distributed total energy intakes may have on weight and metabolic health.
Expert Review
Conflicts of interest:
None
Take Home Message:
Implementing a dietary strategy where a higher proportion of energy is consumed earlier in the day may offer additional benefits to an energy restricted diet for weight loss, blood glucose, improve markers of insulin resistance, increase satiety and improve hunger management. Based on the findings, earlier distribution of energy intake may serve as an effective component of a weight loss protocol.
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:
Background
Chrononutrition refers to the timing and distribution of total daily energy intake across the day. It has been proposed that consuming a greater proportion of total daily energy intake earlier in the day as opposed to the evening may be beneficial for weight loss and metabolic health.
Aims
This systematic review and meta-analysis aimed to assess the impact of earlier versus later distribution of total daily energy intake on weight loss.
Results
A total of 9 randomised controlled trials involving 485 participants were included in this analysis. The study durations ranged from 5-16 weeks. All of the studies included in this analysis applied energy-restricted diets to both intervention arms. The mean percentages of energy intake in 8 of the 9 studies per meal were:
- Earlier distributed intakes: breakfast: 34% ± 16%, lunch: 38% ± 7%, dinner: 20% ± 6%.
- Later distributed intakes: breakfast: 19% ± 6%, lunch: 30% ± 10%, dinner; 40% ± 11%.
One of the studies advised percentage of energy intakes as either:
- Earlier: 70% for breakfast, morning tea and lunch and 30% for afternoon tea and dinner
- Late: 55% for breakfast, morning tea and lunch and 45% for afternoon tea and dinner.
The earlier distributed energy intake groups demonstrated significantly greater weight loss when compared with later distributed energy intake groups ( Mean Difference (MD) −1.23 kg; 95% CI −2.40, −0.06, p = 0.04;
I2 = 98%).
The earlier energy intake groups also displayed lower fasting and bedtime glucose levels (fasting: −0.83 vs. −0.27 mmol/L, p = 0.001; before sleep: −1.70 vs. −0.28 mmol/L, p = 0.009).
A random-effects model demonstrated that the earlier intake groups displayed greater reductions in LDL (MD: −0.11 mmol/L; 95% CI −0.14, −0.07, p < 0.01), fasting glucose (MD: 0.15 mmol/L, 95% CI −0.23, −0.06, p < 0.001) and HOMA-IR (MD: −0.38; 95% CI −0.64, −0.11, p = 0.005).
One study reported that earlier distribution energy intake also led to a greater reduction in medications following the intervention for type 2 diabetics (31% vs. 0%, P=0.002).
Two of the studies assessed both appetite and hunger and identified that earlier distribution of energy led to improvements in their urge to eat, preoccupation with food and cravings for sweets and fats.
Clinical practice applications:
Earlier distribution of energy intake may be beneficial for:
- Weight loss
- Improve fasting insulin, HOMA-IR, fasting glucose and HbA1c
- Reducing LDL
- Improving satiety and hunger management
- Supporting the reduction of medications for individuals with type 2 diabetes
- Improving regularity of sleep and waking times
Considerations for future research:
As the included studies only ranged from 5-16 weeks, longer duration studies would be useful to identify the effect of earlier distribution of energy intake on body weight, metabolic health and appetite over a longer period of time. There was a high degree of heterogeneity between the studies and a lack of uniformity in the distributions of energy intake across the day. Further studies with more uniformity of energy distribution would be needed to identify the optimal distribution of energy across the day to improve body weight and metabolic health.
Abstract
Consuming a greater proportion of total energy intake earlier in the day rather than in the evening is proposed to positively influence weight loss and health, potentially due to greater synchronization of human body circadian rhythms. This systematic review provides an update on existing evidence regarding earlier distributed eating patterns in weight loss interventions. Using a robust search strategy in five electronic databases, nine randomized controlled trials investigating the impact of energy intake distribution on weight loss were identified. Following critical appraisal, a random-effects meta-analyses found that, in the context of an energy-reduced diet, distributing energy intake with a focus on earlier intake resulted in significantly greater weight loss (-1.23 kg; 95% CI 2.40, -0.06, p = 0.04). Improvements in HOMA-IR, fasting glucose, and LDL cholesterol were also seen. The current study provides a timely update on the evidence linking distribution of total daily energy intake and health, showing that a focus on earlier intakes can result in greater short-term weight loss compared with later intakes. Future studies are needed to elucidate the impact that earlier intakes may have on weight management and metabolic health.
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2.
The Effect of Regular Consumption of Reformulated Breads on Glycemic Control: A Systematic Review and Meta-Analysis of Randomized Clinical Trials.
Schadow, AM, Revheim, I, Spielau, U, Dierkes, J, Schwingshackl, L, Frank, J, Hodgson, JM, Moreira-Rosário, A, Seal, CJ, Buyken, AE, et al
Advances in nutrition (Bethesda, Md.). 2023;14(1):30-43
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The metabolic effect of bread depends on several qualitative aspects ranging from the type of grain, the amount of carbohydrates, levels of other nutrients, as well as the chemical structure and processing. The aim of this study was to assess the certainty of the evidence and to investigate the overall effect of regular consumption of reformulated breads on glycaemic control in the following groups: a) healthy adults; b) those at risk of developing cardiometabolic disease (e.g., having hypertension, hyperglycaemia, hypercholesterolemia and/or overweight/obesity); and c) those with manifest type 2 diabetes mellitus (T2DM). This study is a systematic review and meta-analysis of 22 studies and 23 distinct study populations. All studies were randomised controlled trials, 12 of which had a crossover design and 10 had a parallel design. In total, 1037 participants were included. These provided 669 and 595 data points for intervention and control comparisons, respectively. Results show a beneficial effect of reformulated bread variants on fasting blood glucose concentrations. This benefit may be more pronounced among people with manifest T2DM (low certainty of evidence). Authors conclude that bread quality is relevant for metabolic health among adults and that future studies should address its relevance among people at risk of T2DM.
Expert Review
Conflicts of interest:
None
Take Home Message:
This study’s findings suggest the effect of reformulated breads high in dietary fibre, whole grains, and/or functional ingredients may be more beneficial than regular breads on fasting blood glucose concentrations in adults, primarily among those with T2DM. Reformulated breads however, did not lower fasting insulin concentrations, HOMA-IR and HbA1C when compared to regular bread.
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:
Overview
This study evaluated the effect of regular consumption of “reformulated breads” on glycemic control among healthy adults, adults at cardiometabolic risk or with manifest T2DM in 22 RCTs with 1037 participants. Compared with “regular” or comparator bread, consumption of reformulated intervention breads yielded lower fasting blood glucose concentrations only among people with T2DM (low certainty of evidence), yet no differences in fasting insulin, HOMA-IR, HbA1c, or postprandial glucose response were identified.
[*’reformulated bread’ as defined by the World Health Organisation of altering the processing or composition of a food to improve its nutritional profile, and contained whole-grains and dietary fibre]
Results
Sub group analysis revealed that the effect of reformulated breads high in dietary fibre, whole grains, and/or functional ingredients on lowering fasting blood glucose was confined to participants with T2DM, with no significant effect among participants without T2DM (0.68 mmol/L; 95% CI: 1.11, 0.36; I2 1⁄4 57% and 0.04 mmol/L; 95% CI: 0.13, 0.05; I2 1⁄4 25%, respectively; P < 0.001).
Subgroup analyses by continent revealed a more pronounced effect on fasting blood glucose concentrations in studies conducted in Asia and the Middle East compared with studies conducted in Europe, North America, and Oceania (MD: 0.84 mmol/L; 95% CI: 1.35, 0.33; I2 1⁄4 52% and MD: 0.04 mmol/L; 95% CI: 0.10, 0.03; I2 1⁄4 0%, respectively; P < 0.001)
Additional subgroup analyses found that the type of control bread, but not the type of intervention bread, affected the pooled effect estimate of fasting blood glucose concentration (P 1⁄4 0.03), with the largest difference reported in studies not describing the control bread used.
Limitations
Publication bias was considered negligible for the studies included in this meta-analysis, and the risk of bias assessment revealed that most of the studies had some concerns of risk of bias. One author is a member of the International Carbohydrate Quality Consortium and another is a member of the GRADE working group.
Strengths
This systematic review and meta-analysis include the focus on high-quality intervention studies (i.e., RCTs using either crossover or parallel design) and the inclusion of longer-term studies (>2 wk) to address the effectiveness of regular bread replacement for glycemic control in everyday life.
Clinical practice applications:
- This data suggests that bread quality is relevant for metabolic health among adults at risk of T2DM. In particular, reformulated breads were found to have a more beneficial impact than regular breads on fasting blood glucose concentrations in adults with TsDM. However, consumption of the reformulated bread (enriched with dietary fiber, whole grains, or functional ingredients) did not lower fasting insulin concentrations compared with the control breads (MD: 1.59 pmol/L; 95% CI: 5.78, 2.59; moderate certainty of evidence)
- Consumption of the reformulated bread did not lower HOMA-IR compared with the control breads (MD: 0.09; 95% CI: 0.35, 0.22; moderate certainty of evidence)
- Consumption of the reformulated bread did not lower HbA1c concentrations compared with the control bread (0.14; 95% CI: 0.39, 0.10; P 1⁄4 0.195; very low certainty of evidence).
Considerations for future research:
- Longer intervention periods may be required to determine the beneficial effects on the HbA1c concentrations and to elicit changes in markers of insulin resistance
- Future studies should use the 2022 WHO standardised HbA1c diagnostic reference criterion for diabetes mellitus
- Improvements in specific outcomes may also be linked to defined groups within populations such as persons with manifest T2DM.
- The type of reformulation of the bread may be an important factor but differ considerably around the world
Abstract
Bread is a major source of grain-derived carbohydrates worldwide. High intakes of refined grains, low in dietary fiber and high in glycemic index, are linked with increased risk for type 2 diabetes mellitus (T2DM) and other chronic diseases. Hence, improvements in the composition of bread could influence population health. This systematic review evaluated the effect of regular consumption of reformulated breads on glycemic control among healthy adults, adults at cardiometabolic risk or with manifest T2DM. A literature search was performed using MEDLINE, Embase, Web of Science and the Cochrane Central Register of Controlled Trials. Eligible studies employed a bread intervention (≥2 wk) in adults (healthy, at cardiometabolic risk or manifest T2DM) and reported glycemic outcomes (fasting blood glucose, fasting insulin, HOMA-IR, HbA1c, and postprandial glucose responses). Data were pooled using generic inverse variance with random-effects model and presented as mean difference (MD) or standardized MD between treatments with 95% CIs. Twenty-two studies met the inclusion criteria (n = 1037 participants). Compared with "regular" or comparator bread, consumption of reformulated intervention breads yielded lower fasting blood glucose concentrations (MD: -0.21 mmol/L; 95% CI: -0.38, -0.03; I2 = 88%, moderate certainty of evidence), yet no differences in fasting insulin (MD: -1.59 pmol/L; 95% CI: -5.78, 2.59; I2 = 38%, moderate certainty of evidence), HOMA-IR (MD: -0.09; 95% CI: -0.35, 0.23; I2 = 60%, moderate certainty of evidence), HbA1c (MD: -0.14; 95% CI: -0.39, 0.10; I2 = 56%, very low certainty of evidence), or postprandial glucose response (SMD: -0.46; 95% CI: -1.28, 0.36; I2 = 74%, low certainty of evidence). Subgroup analyses revealed a beneficial effect for fasting blood glucose only among people with T2DM (low certainty of evidence). Our findings suggest a beneficial effect of reformulated breads high in dietary fiber, whole grains, and/or functional ingredients on fasting blood glucose concentrations in adults, primarily among those with T2DM. This trial was registered at PROSPERO as CRD42020205458.
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3.
The Effect of Curcumin on Lipid Profile and Glycemic Status of Patients with Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis.
Tian, J, Feng, B, Tian, Z
Evidence-based complementary and alternative medicine : eCAM. 2022;2022:8278744
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Dyslipidaemia is a common comorbidity of type 2 diabetes mellitus (T2DM), which is characterised by elevated triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c) level, and/or decreased high-density lipoprotein cholesterol (HDL-c) concentrate serum. Dyslipidaemia and dysglycemia interact with each other, and they are the main risk factors of macro- and microvascular diseases in T2DM. The aim of this study was to outline curcumin’s efficacy and possible uses in clinical practice. This study is a meta-analysis of nine randomised controlled trials (RCTs). A total of 604 participants (284 in the curcumin group and 281 in the control group) were included in the selected studies. The design of all trials was parallel; seven of them were double-blind RCTs, and the other two were open label RCTs. Results show that curcumin significantly decreased TG, TC, fasting blood glucose, and haemoglobin A1C levels and also led to a reduction in LDL-c and an elevation in HDL-c concentration, although with no statistical difference. Authors conclude that curcumin has promising effects on the lipid profile and glycaemic status in patients with T2DM. It indicated that curcumin might be a favourable therapeutic option for T2DM patients with mixed dyslipidaemia.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Dyslipidemia and dysglycemia interact with each other, and are risk factors of macro- and microvascular diseases in T2DM.
Although effective intervention strategies exist for improving glycemic status of T2DM patients, they often need lipid-lowering drugs simultaneously to prevent CVD.
- Novel therapeutic interventions are needed to manage dyslipidemia and dysglycemia in diabetic patients, when statin therapy to treat dyslipidemia, may increase the risk of new-onset diabetes and myopathy.
- Other clinical studies have highlighted the benefits of curcumin supplementation on lipid profile and glycemic status. Clarifying its effects is important for assessing its potential as an alternative and complementary medicine on improving the metabolic status of T2DM patients.
- Overall there is limited evidence and further research is required.
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
This meta-analysis aimed to evaluate the effects of curcumin on lipid profile in patients with type 2 diabetes mellitus (T2DM), including: serum triglycerides (TG), total cholesterol (TC), low-density lipoprotein (LDL-c), and/or high-density lipoprotein cholesterol (HDL-c). Fasting blood glucose (FBG) and glycated hemoglobin (HbA1c) were also assessed.
Methods
A search was performed on Pubmed, Embase, Web of Sciences, and the Cochrane Library up to March 2022. Quality assessment of all included studies was performed.
Results
9 studies were included in the review, with a total of 604 participants (284 in the curcumin group and 281 in the control group) of mean age from 41 to 60.95 years. Curcumin forms varied among the studies including, turmeric, curcuminoids, and curcumin. The dosage of curcumin in the intervention group ranged from 80 to 2100 mg/day. The duration of intervention was between 4 weeks and 3 months in different studies.
- Effect of Curcumin on TG: A difference was observed between curcumin supplementation and control (p = 0.03), indicating curcumin could reduce serum TG.
- Effect of Curcumin on TC: The mean difference in net changes of TC between intervention and control groups was −8.91mg/dL (p = 0.001), suggesting that curcumin could decrease serum TC.
- Effect of Curcumin on LDL-C: No difference in the net change of LDL-c between intervention and control groups (p = 0.26).
- Effect of Curcumin on HDL-C: No difference in HDL-c between intervention and control groups (p = 0.56).
- Effect of Curcumin on FBG: Curcumin reduced blood glucose levels compared with control treatment (p = 0.002). The effect was greater in trials with the treatment duration >8w (p = 0.037), curcumin dose >100mg/day (p = 0.004), and with the participants receiving the other therapy (p = 0.002).
- Effect of Curcumin on HbA1c: HbA1c (%) decreased in the intervention group compared with the control group (p ≤ 0.001).
Conclusion
Curcumin has promising effects on the lipid profile and glycemic status of T2DM patients and might be a therapeutic option for T2DM patients with mixed dyslipidemia.
Clinical practice applications:
- Limitations were the small number of included studies, mostly with small sample sizes. In some studies, treatment duration was short (<2 months) and may be insufficient to see a difference in some metabolic parameters.
- The reduction of FBG and HbA1c after treatment with curcumin suggested that it improved the glycemic metabolism in the T2DM patients studied.
- Studies have shown that curcumin could promote insulin release through inducing β-cell electrical activity and lower serum glucose level via decreasing the production of hepatic glucose and increasing glucose uptake. While changes of LDL-c and HDL-c was not statistically significant, the authors note the effect of curcumin on LDL-c/HDL-c and its potential clinical significance could not be neglected.
- The reduction of dyslipidemia by curcumin supplementation could improve the glucose metabolic status of T2DM patients, and multiple molecular targets including PPAR-c, cholesteryl ester transfer protein, and lipoprotein lipase contribute to the beneficial effects of curcumin.
Considerations for future research:
- While significant heterogeneity was found in pooled analyses of TG, LDL-c, FBG, and Hb1Ac, a random-effects model revealed that trial duration, curcumin dosage, and other therapy may contribute to the variation in pooled effects, and these aspects could be discussed in future studies.
- The study found that a higher dose of curcumin was more powerful in reducing plasma TG and FBG concentrations, but further large-scale multicenter RCTs are required to confirm the clinical improvement of curcumin.
Abstract
Type 2 diabetes mellitus (T2DM) is a progressive metabolic disorder, some natural compounds are thought to be beneficial in improving the metabolic status of patients with T2DM. Curcumin is the main bioactive agent of turmeric, the impact of curcumin on T2DM is still controversial. This meta-analysis aimed to evaluate the effects of curcumin on lipids profile and glucose status in patients with T2DM. Randomized controlled trials (RCTs) examining the effects of curcumin on lipids profile and glycemic control of T2DM patients were searched in PubMed, Embase, Web of Science and Cochrane Library. Pooled estimates of weighted mean difference (WMD) were calculated between intervention and control groups using random-effects or fixed-effects model. Subgroup and sensitivity analyses were conducted to assess the effects. Nine eligible RCT with 604 subjects were included. The estimated pooled mean changes with curcumin were -18.97 mg/dL (95% CI: -36.47 to -1.47; P=0.03) for triglyceride (TG), -8.91 mg/dL (95% CI: -14.18 to -3.63, P=0.001) for total cholesterol (TC), -4.01 mg/dL (95% CI: -10.96 to 2.95, P=0.259) for low density lipoprotein cholesterol (LDL-c), 0.32 mg/dL (95% CI: -0.74 to 1.37, P=0.557) for high density lipoprotein cholesterol (HDL-c), -8.85 mg/dL (95% CI: -14.4 to -3.29, P=0.002) for fasting blood glucose (FBG), -0.54 (95% CI: -0.81 to -0.27, P ≤ 0.001) for glycated hemoglobin (HbA1c) (%) compared with controls. There was a significant heterogeneity for the influence of curcumin on TG, LDL-c, FBG and HbA1c. Subgroup analysis revealed that the heterogeneity mainly attributed to trial period, curcumin dosage and other therapy. The results of this study showed that curcumin supplementation had beneficial effects on glycemic status and some lipid parameters in patients with T2DM. Further studies with large-scale are still needed to confirm the results.
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4.
Low-carbohydrate diets and men's cortisol and testosterone: Systematic review and meta-analysis.
Whittaker, J, Harris, M
Nutrition and health. 2022;28(4):543-554
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Testosterone is the primary male sex hormone, and vital for reproductive development and function. Moreover, low endogenous testosterone is associated with an increased risk of chronic disease, including type 2 diabetes and cardiovascular disease. The aim of this study was to investigate the effects of low- versus high-carbohydrate diets on mens' testosterone and cortisol. This study is a systematic review and meta-analysis of twenty-seven studies with a total of 309 participants. Twelve of these studies were randomised trials whilst the rest were non-randomised. Results show an increase in resting and post-exercise cortisol on short-term low-carbohydrate diets (<3 weeks). In fact, resting cortisol levels return to baseline after <3 weeks on a LC diet, whilst post-exercise cortisol remains elevated. Furthermore, high-protein diets cause a large decrease in resting total testosterone. Authors conclude that further research is required in order to warrant their findings.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Short-term LC-diets diets cause a moderate increase in resting and post-exercise cortisol however this effect is not seen in LC-diets followed for great than 3 weeks
- HP-LC diets caused a statistically significant decrease in resting TT, suggesting caution in relation to endocrine effects of LC diets
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:
A systematic review and network meta-analysis was conducted on the effects of low-carbohydrate (LC) versus high-carbohydrate (HC) diets on men’s testosterone and cortisol.
The review was registered with PROSPERO and reported using PRISMA 2020 checklists.
Methods:
A comprehensive search strategy was used to find intervention studies looking at healthy adult males and LC diets of <35% carbohydrate. Studies were assessed for quality using the Cochrane Risk of Bias tool. Sub-group analyses was conducted for diet duration, protein intake and exercise duration.
Results:
The literature search resulted in 27 studies with a total of 309 healthy adult male participants, age: 27.3 ± 4.7 (to minimise variation in steroid hormone metabolism), body mass: 78.6± 7.1kg and BMI: 24.8 ±1.6. 12 randomised and 15 non-randomised controlled trials were analysed. 21 studies were considered low risk bias, 5 medium and 1 high risk.
- Short-term (<3 weeks) LC diets moderately increased resting cortisol (0.41 [0.16, 0.66], p < 0.01) when compared to HC diets.
- Long-term (≥3 weeks) LC diets had no consistent effect on resting cortisol
- LC diets resulted in higher post-exercise cortisol, after long-duration exercise (≥20 min): 0 h (0.78 [0.47, 1.1], p < 0.01), 1 h (0.81 [0.31, 1.31], p < 0.01), and 2 h (0.82 [0.33, 1.3], p < 0.01).
- The overall results for resting total testosterone (TT) showed a significant decrease on LC versus HC diets (SMD = −0.48, p = 0.01. However, subgroup analyses revealed this effect to be limited to high-protein (HP) LC diets, which yielded a very large decrease in TT (SMD = −1.08, p < 0.01; ∼5.23 nmol/L), albeit in a small sample (n = 26).
- Moderate protein (MP) (<35%), low-carbohydrate diets had no consistent effect on resting total testosterone, however high-protein (≥35%), low-carbohydrate diets greatly decreased resting (−1.08 [−1.67, −0.48], p < 0.01) and post-exercise total testosterone (−1.01 [−2, −0.01] p = 0.05).
- There was no overall effect of LC versus HC diets on 0 h post-exercise TT (SMD = −0.03, p = 0.95). However, subgroup analysis showed 0 h post-exercise was non-significantly higher on long-term LC versus HC diets (SMD = 0.44, p = 0.18), and much lower on short-term LC versus HC diets (SMD = −1.01, p = 0.05)
Conclusion:
This systematic review and metanalysis found an increase in resting and post-exercise cortisol on short-term LC diets. Cortisol does return to baseline in the first 3 weeks of a low-carbohydrate (LC) diet. The same response is, however, not seen in post-exercise cortisol, which remains elevated. In addition, the review showed that compared to moderate-protein diets, HP diets were found to cause a large decrease in resting and post-exercise TT (∼5.23 nmol/L).
Clinical practice applications:
The results of this review suggest that exercising whilst following a LC diet can increase cortisol in the short term, but not long-term. This suggests a period of diet adaptation. The effects of long-term LC diets on cardiovascular disease risk is uncertain and healthcare practitioners should monitor client responses and keep up-to-date with new research in this area
Since HP-LC diets were found to significantly decrease resting testosterone it highlights the need to ensure that protein intake does not exceed the urea cycle’s capacity due to potential adverse endocrine effects.
For clients where there is a desire to increase strength, power and hypertrophy, a MP-LC diet could be of benefit, as it showed potential to signal an increased anabolic state post exercise..
NB: Since the review only included a low number of studies and saw within these some heterogeneity that could not be explained, more research is needed before the paper’s findings can be conclusive. The above potential practice applications should therefore be seen as something to be mindful of when working with clients where cortisol and testosterone levels are relevant to their protocol.
Considerations for future research:
Future research should consider:
- Since LC diets have been shown to have a positive effect on health – decreased triglycerides, increased high density lipoprotein cholesterol and weight loss - future studies would benefit from including these markers so any positive and negative impacts can be monitored directly.
- Despite extensive analysis including sensitivity analysis to reduce bias and heterogeneity of the results, the paper highlights a need for further research to ensure consistency in key parameters e.g., exercise duration and intensity, carbohydrate supplements inclusion and period of dietary intervention. Since it was identified that HP-LP diets impact post exercise and resting TT, follow up studies would benefit from consistency in participants diets. This would help to reduce any potential confounding results.
Abstract
Background: Low-carbohydrate diets may have endocrine effects, although individual studies are conflicting. Therefore, a review was conducted on the effects of low- versus high-carbohydrate diets on men's testosterone and cortisol. Methods: The review was registered on PROSPERO (CRD42021255957). The inclusion criteria were: intervention study, healthy adult males, and low-carbohydrate diet: ≤35% carbohydrate. Eight databases were searched from conception to May 2021. Cochrane's risk of bias tool was used for quality assessment. Random-effects, meta-analyses using standardized mean differences and 95% confidence intervals, were performed with Review Manager. Subgroup analyses were conducted for diet duration, protein intake, and exercise duration. Results: Twenty-seven studies were included, with a total of 309 participants. Short-term (<3 weeks), low- versus high-carbohydrate diets moderately increased resting cortisol (0.41 [0.16, 0.66], p < 0.01). Whereas, long-term (≥3 weeks), low-carbohydrate diets had no consistent effect on resting cortisol. Low- versus high-carbohydrate diets resulted in much higher post-exercise cortisol, after long-duration exercise (≥20 min): 0 h (0.78 [0.47, 1.1], p < 0.01), 1 h (0.81 [0.31, 1.31], p < 0.01), and 2 h (0.82 [0.33, 1.3], p < 0.01). Moderate-protein (<35%), low-carbohydrate diets had no consistent effect on resting total testosterone, however high-protein (≥35%), low-carbohydrate diets greatly decreased resting (-1.08 [-1.67, -0.48], p < 0.01) and post-exercise total testosterone (-1.01 [-2, -0.01] p = 0.05). Conclusions: Resting and post-exercise cortisol increase during the first 3 weeks of a low-carbohydrate diet. Afterwards, resting cortisol appears to return to baseline, whilst post-exercise cortisol remains elevated. High-protein diets cause a large decrease in resting total testosterone (∼5.23 nmol/L).
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5.
Cadmium exposure and risk of diabetes and prediabetes: A systematic review and dose-response meta-analysis.
Filippini, T, Wise, LA, Vinceti, M
Environment international. 2022;158:106920
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Cadmium is a toxic metal released in the environment after both natural and anthropogenic activities, particularly in contaminated and industrial areas devoted to smelting and refining of metals, and the manufacturing of batteries, coatings, or plastics. Exposure to cadmium may occur through occupational activities, smoking, food, and air pollution. The aim of this study was to provide updated literature on cadmium exposure and the risk of both type 2 diabetes and prediabetes, and to model the shape of these associations using a dose response approach. This study is a systematic review and meta-analysis of forty-two studies. Diabetes was investigated as an outcome in thirty-one studies, prediabetes in four studies, and both diabetes and prediabetes in seven studies. Results show that higher cadmium exposure was associated with increased risks of both diabetes and prediabetes. Diabetes risk increased linearly in studies using urinary cadmium concentrations, while disease risk increased only at the highest exposure levels when assessed using blood concentrations. The analysis for prediabetes also showed a linear increase in risk from low exposure, with a flattening effect at higher urinary cadmium concentrations. Authors conclude that their findings add to the available evidence on potential adverse health effects of environmental exposure to cadmium.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Cadmium exposure through diet, occupational exposure and smoking may increase the risk of type 2 diabetes in affected individuals.
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:
Background
Cadmium exposure might occur through occupational activities, food, air pollution, and smoking. Smokers, in particular, have higher blood cadmium concentrations than non-smokers. Food is the main transmission route for non-smokers, particularly cereals, vegetables, mollusks, and offal. Females and older adults are at a greater risk due to an increased risk of iron deficiency in these population groups, leading to increased absorption, as well as greater age-related bioaccumulation.
Furthermore, cadmium exposure has been associated with an increased risk of diabetes in a number of studies, as referenced in the present manuscript. However, the magnitude and shape of the correlation are uncertain.This systematic review and meta-analysis therefore investigates the relationship between exposure to cadmium and type 2 diabetes and prediabetes risk.
Methods
- The systematic review was conducted and reported in line with the PRISMA 2020 statement. Search strings related to the terms “cadmium” and “diabetes”, or “prediabetes state” in PubMed/MEDLINE, Web of Science and EMBASE databases were employed to search for relevant articles. Latest search date: 1 October 2021.
- Eligibility criteria included: studies evaluating cadmium exposure via biomarker levels with outcomes of interest being type 2 diabetes or prediabetes using WHO criteria and the American Diabetes Association; and reporting of relative risk estimates using the hazard ratio (HR), risk ratio (RR), or odds ratio (OR) with the corresponding 95% confidence interval (CIs). For inclusion in dose-response meta-analysis: reported effect estimates for all exposure categories along with dose in each category.
- Studies were assessed for risk of bias using theROBINS-E tool. Overall certainty of the evidence was assessed using the GRADE approach.
- The meta-analysis involved estimating RRs with corresponding 95% CIs from each study. Generalised least-squares regression with a random effects model and restricted maximum likelihood estimation were used. The highest versus lowest exposure categories were compared. The association between exposure and risk of diabetes or prediabetes was investigated using a one-stage dose-response meta-analysis. Sensitivity analyses were performed and heterogeneity between studies was assessed..
Results
- 42 eligible studies (case-control, cross-sectional, and cohort studies), ranging 65-34, 814 male and female adult participants, were identified investigating the association between cadmium exposure and risk of diabetes or prediabetes. Seven of the included studies were at overall high risk of bias; heterogeneity in the resulting meta-analyses was moderate to substantial. Sensitivity analyses indicated comparable results. Assessment with GRADE found no major inconsistency, indirectness or imprecision for either outcome.
- Comparing the highest versus lowest cadmium exposure concentrations associated with type 2 diabetes resulted in a RR of 1.24 (95% CI 0.96–1.59), RR 1.21 (CI 95% 1.00–1.45), and RR 1.47 (CI 95% 1.01–2.13) for blood, urinary, and toenail matrices, respectively. Concurrently, there was an elevated risk of prediabetes for cadmium levels in urine of RR 1.41 (95% CI: 1.15–1.73) and blood RR 1.38 (95% CI: 1.16–1.63), respectively.
- In the dose-response meta-analysis, a linear positive correlation between increasing urinary cadmium levels and diabetes risk was observed, with a RR 1.25 (95% CI 0.90–1.72) at concentration 2.0 µg/g of creatinine compared with no exposure. Conversely, for blood cadmium concentrations, the diabetes risk seemed to rise above 1 µg/L compared with no exposure. Moreover, prediabetes risk increased up to approximately 2 µg/g creatinine beyond which a plateau was reached with RR 1.40 (95% CI 1.12–1.76) at 2 µg/g creatinine.
- The meta-regression showed a negligible correlation between blood cadmium levels and diabetes risk. However, a positive yet imprecise association was found with increasing urinary cadmium concentrations. Similarly, no association was observed between blood cadmium concentrations and risk of prediabetes, whereas a positive relationship with urinary cadmium levels was observed. However, these findings were based on a limited cohort of studies.
Conclusions
- A positive linear correlation between cadmium concentration (measured in multiple matrices) and risk of both type 2 diabetes and prediabetes with a dose-response relationship (moderate-certainty evidence) were observed in this systematic review and meta-analysis. Diabetes risk increased linearly in studies using urinary cadmium concentrations, whereas disease risk increased only at the highest exposure levels when assessed using blood levels. The analysis for prediabetes also demonstrated a linear increase in risk from low exposure, which plateaued at higher urinary cadmium concentrations.
Clinical practice applications:
- To inform practitioners and clients of the risks of cadmium exposure in the diet, through occupational exposure, and through smoking.
- To motivate practitioners to educate themselves and their clients regarding the foods which may pose a higher risk of cadmium exposure (not reviewed in the present article).
- To advise clients on prediabetes and type 2 diabetes risk from cadmium exposure through smoking.
Considerations for future research:
- As cited by the authors, future studies could incorporate stratified analysis in specific subgroups, e.g., non-smokers, or could be restricted to prospective cohort studies with more sufficient data,
- Large-scale observational studies could be conducted investigating cadmium exposure in smokers versus non-smokers.
- Clinical trials could be performed to evaluate the effect of reduction or cessation of tobacco smoking on total body cadmium concentrations .
- Continuous surveillance of dietary cadmium exposure and other heavy metals should be prioritised to inform public health.
- Dietary interventions could assess the possibility to attenuate the risk of cadmium exposure.
Abstract
BACKGROUND Cadmium exposure has been associated with increased diabetes risk in several studies, though there is still considerable debate about the magnitude and shape of the association. OBJECTIVE To perform a systematic review and meta-analysis of observational studies investigating the relation between cadmium exposure and risk of type 2 diabetes and prediabetes, and to summarize data on the magnitude and shape of the association. DATA SOURCE After conducting an online literature search through October 1, 2021, we identified 42 eligible studies investigating the association between cadmium exposure and risk of diabetes and prediabetes. STUDY ELIGIBILITY CRITERIA We included studies that assessed cadmium exposure through biomarker levels; examined type 2 diabetes or prediabetes among outcomes; and reported effect estimates for cadmium exposure for meta-analysis only. STUDY APPRAISAL AND SYNTHESIS METHODS Studies were evaluated using ROBINS-E risk of bias tool. We quantitively assessed the relation between exposure and study outcomes using one-stage dose-response meta-analysis with a random effects meta-analytical model. RESULTS In the meta-analysis, comparing highest-versus-lowest cadmium exposure levels, summary relative risks (RRs) for type 2 diabetes were 1.24 (95% confidence interval 0.96-1.59), 1.21 (1.00-1.45), and 1.47 (1.01-2.13) for blood, urinary, and toenail matrices, respectively. Similarly, there was an increased risk of prediabetes for cadmium concentrations in both urine (RR = 1.41, 95% CI: 1.15-1.73) and blood (RR = 1.38, 95% CI: 1.16-1.63). In the dose-response meta-analysis, we observed a consistent linear positive association between cadmium exposure and diabetes risk, with RRs of 1.25 (0.90-1.72) at 2.0 µg/g of creatinine. Conversely for blood cadmium, diabetes risk appeared to increase only above 1 µg/L. Prediabetes risk increased up to approximately 2 µg/g creatinine above which it reached a plateau with RR of 1.42 (1.12-1.76) at 2 µg/g creatinine. LIMITATIONS AND CONCLUSIONS This analysis provides moderate-certainty evidence for a positive association between cadmium exposure (measured in multiple matrices) and risk of both diabetes and prediabetes.
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6.
Efficacy and safety of low and very low carbohydrate diets for type 2 diabetes remission: systematic review and meta-analysis of published and unpublished randomized trial data.
Goldenberg, JZ, Day, A, Brinkworth, GD, Sato, J, Yamada, S, Jönsson, T, Beardsley, J, Johnson, JA, Thabane, L, Johnston, BC
BMJ (Clinical research ed.). 2021;372:m4743
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Plain language summary
Diet modification has long been recognised as a component for the treatment of diabetes. Diets low in carbohydrates have been extensively researched, as a diet for those with Type 2 Diabetes (T2D). This systematic review and meta-analysis aimed to determine the effect of low carbohydrate diets on T2D. The systematic review found 23 studies, including 1357 individuals, investigating the role of low carbohydrate diets on T2D outcomes. Low carbohydrate diet was defined as less than 130g of carbohydrate (less than 26% of calories from carbohydrate) for at least 12 weeks. Results reported at 6 months, found low carbohydrate diets were more effective than a normal diet at achieving diabetes remission. However, this effect diminished at 12 months, although longer term improvements were seen in blood lipids, weight loss and measures of prediabetes. It was concluded that individuals with T2D, eating a low carbohydrate diet for 6 months may reverse the disease. This study could be used by healthcare professionals to recommend a short-term low carbohydrate diet to individuals with T2D, to improve their chance of going into remission.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Type 2 diabetes remains a significant and worsening problem worldwide, despite many pharmaceutical developments and a global emphasis on glycemic control.
- This review highlights structured LCDs as a worthwhile option for the management and treatment of diabetes, providing an opportunity for Nutritional Therapy Practitioners to support clients in adopting evidence-informed, modifiable dietary and lifestyle changes for Type Two Diabetes.
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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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:
- Type 2 diabetes is the most common form of diabetes, accounting for 90-95% of cases.
- Previous randomised trials assessed low carbohydrate diets (LCDs) (<26-45% of daily calories from carbohydrate) as encouraging to improve blood glucose control and outcomes of type 2 diabetes but did not systematically assessed remission of diabetes using low carbohydrate diets (LCDs) and very low carbohydrate diets (VLCDs) for people with type 2 diabetes.
- Systematic reviews (SR) and meta-analyses represent the most valuable, reliable, and objective tool to summarise evidence from primary studies.
- This SR assessed 23 randomised controlled trials comparing LCDs with mostly low fat control diets in individuals / subjects / participants with type 2 diabetes. LCDs were defined as diets with less than 130 g/day or less than 26% of calories from carbohydrates, based on 2000 kcal/day. The authors used the Cochrane Risk of Bias tool 2.0 (RoB 2) to assess methodological quality of evidence, GRADE to assess the certainty of evidence
- On the basis of assessment of moderate to low certainty evidence, individuals / subjects / participants adhering to a LCD for six months may experience remission of type 2 diabetes without adverse consequences.
- Primary outcomes of interest were remission of type 2 diabetes (dichotomously defined as HbA1c <6.5% or fasting glucose <7.0 mmol/L), with or without the use of diabetes medication.
- Eight studies reported on remission of diabetes at six months. Pooled analysis showed that when remission was defined by an HbA1c level below 6.5% independent of medication use, LCDs increased remissions by an additional 32 per 100 patients followed (risk difference 0.32, 95% confidence interval 0.17 to 0.47; 8 studies, n=264; GRADE=moderate)
- When remission was defined by an HbA1c level below 6.5% and the absence of diabetes medication, LCDs increased remissions at a lower rate (risk difference 0.05, –0.05 to 0.14; 5 studies, n=199; GRADE=low)
- Additional primary outcomes were weight loss, HbA1c:
- 18 studies reported on Weight loss results (mean difference –3.46, 95% confidence interval –5.25 to –1.67; n=882 (note that positive results not sustained at 12 mo)
- Seventeen studies reported on HbA1c levels at six months, LCDs achieved greater reductions in HbA1c than did control diets (mean difference –0.47%, –0.60 to –0.34; n=747
- Limitations of study: 1) the definition of remission of diabetes, 2) Self-reported dietary intake data are prone to measurement error, particularly in dietary trials in which participants are not blinded
- This SR was funded in part by Texas A&M University.
- The authors declared no conflicts of interest.
Clinical practice applications:
The Authors highlight LCD diets incorporating carbohydrate of less than 130 g/day or less than 26% of calories (based on 2000 kcal/day) may be a safe strategy to help individuals with type 2 diabetes achieve weight loss and better blood glucose control over a six-month period. Results may not be sustained at 12 months.
Considerations for future research:
- The definition of diabetes remission needs clarification, especially with regard to threshold concentrations of Hb1Ac or fasting glucose and the use of diabetes medication.
- Safety concerns have been raised with LCDs. Although no significant or clinically important increase in total or serious adverse events was identified in this SR, these outcomes should be reported in future trials to confirm the certainty of evidence for safety.
- The Authors suggest long term, well designed, calorie controlled randomised trials are needed to determine the effects of LCD on sustained weight loss and remission of diabetes.
- Larger treatment effects for LCDs in shorter term trials (3 to <6 months), may be trialed as an effect modifier
Abstract
OBJECTIVE To determine the efficacy and safety of low carbohydrate diets (LCDs) and very low carbohydrate diets (VLCDs) for people with type 2 diabetes. DESIGN Systematic review and meta-analysis. DATA SOURCES Searches of CENTRAL, Medline, Embase, CINAHL, CAB, and grey literature sources from inception to 25 August 2020. STUDY SELECTION Randomized clinical trials evaluating LCDs (<130 g/day or <26% of a 2000 kcal/day diet) and VLCDs (<10% calories from carbohydrates) for at least 12 weeks in adults with type 2 diabetes were eligible. DATA EXTRACTION Primary outcomes were remission of diabetes (HbA1c <6.5% or fasting glucose <7.0 mmol/L, with or without the use of diabetes medication), weight loss, HbA1c, fasting glucose, and adverse events. Secondary outcomes included health related quality of life and biochemical laboratory data. All articles and outcomes were independently screened, extracted, and assessed for risk of bias and GRADE certainty of evidence at six and 12 month follow-up. Risk estimates and 95% confidence intervals were calculated using random effects meta-analysis. Outcomes were assessed according to a priori determined minimal important differences to determine clinical importance, and heterogeneity was investigated on the basis of risk of bias and seven a priori subgroups. Any subgroup effects with a statistically significant test of interaction were subjected to a five point credibility checklist. RESULTS Searches identified 14 759 citations yielding 23 trials (1357 participants), and 40.6% of outcomes were judged to be at low risk of bias. At six months, compared with control diets, LCDs achieved higher rates of diabetes remission (defined as HbA1c <6.5%) (76/133 (57%) v 41/131 (31%); risk difference 0.32, 95% confidence interval 0.17 to 0.47; 8 studies, n=264, I2=58%). Conversely, smaller, non-significant effect sizes occurred when a remission definition of HbA1c <6.5% without medication was used. Subgroup assessments determined as meeting credibility criteria indicated that remission with LCDs markedly decreased in studies that included patients using insulin. At 12 months, data on remission were sparse, ranging from a small effect to a trivial increased risk of diabetes. Large clinically important improvements were seen in weight loss, triglycerides, and insulin sensitivity at six months, which diminished at 12 months. On the basis of subgroup assessments deemed credible, VLCDs were less effective than less restrictive LCDs for weight loss at six months. However, this effect was explained by diet adherence. That is, among highly adherent patients on VLCDs, a clinically important reduction in weight was seen compared with studies with less adherent patients on VLCDs. Participants experienced no significant difference in quality of life at six months but did experience clinically important, but not statistically significant, worsening of quality of life and low density lipoprotein cholesterol at 12 months. Otherwise, no significant or clinically important between group differences were found in terms of adverse events or blood lipids at six and 12 months. CONCLUSIONS On the basis of moderate to low certainty evidence, patients adhering to an LCD for six months may experience remission of diabetes without adverse consequences. Limitations include continued debate around what constitutes remission of diabetes, as well as the efficacy, safety, and dietary satisfaction of longer term LCDs. SYSTEMATIC REVIEW REGISTRATION PROSPERO CRD42020161795.
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7.
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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Plain language summary
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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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.