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Nuts and seeds consumption and risk of cardiovascular disease, type 2 diabetes and their risk factors: a systematic review and meta-analysis.
Arnesen, EK, Thorisdottir, B, Bärebring, L, Söderlund, F, Nwaru, BI, Spielau, U, Dierkes, J, Ramel, A, Lamberg-Allardt, C, Åkesson, A
Food & nutrition research. 2023;67
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Nuts and seeds consumption is associated with a reduced risk of coronary heart disease (CHD) and cardiovascular disease (CVD). Nuts and seeds contain beneficial components to reduce the risk of CVD and CHD; hence dietary addition may benefit heart health. This systematic review and meta-analysis included sixty studies to analyse the effects of the consumption of nuts and seeds on the incidence of mortality from type 2 diabetes (T2D) and CVD and intermediate cardiometabolic risk factors. High nuts and seed consumption showed a 19% reduction in CVD risk and a 23% reduction in CVD mortality. In addition, high consumption lowered the risk of CHD by 25%. Increased nut consumption up to 30 g/day showed a dose-dependent relationship with reduced risk of CVD. Healthcare professionals can use the results of this study to understand the association between nuts and seeds consumption and CHD, CVD and blood lipid levels. However, further robust studies are required to evaluate the effect of specific nuts and seeds on CHD and CVD risk reduction.
Abstract
OBJECTIVES We aimed to systematically review studies and evaluate the strength of the evidence on nuts/seeds consumption and cardiometabolic diseases and their risk factors among adults. METHODS A protocol was pre-registered in PROSPERO (CRD42021270554). We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials and Scopus up to September 20, 2021 for prospective cohort studies and ≥12-week randomized controlled trials (RCTs). Main outcomes were cardiovascular disease (CVD), coronary heart disease (CHD), stroke and type 2 diabetes (T2D), secondary total-/low density lipoprotein (LDL)-cholesterol, blood pressure and glycaemic markers. Data extraction and risk of bias (RoB) assessments (using RoB 2.0 and RoB-NObS) were performed in duplicate. Effect sizes were pooled using random-effects meta-analyses and expressed as relative risk (RR) or weighted mean differences with 95% confidence intervals (CI); heterogeneity quantified as I 2. One-stage dose-response analyses assessed the linear and non-linear associations with CVD, CHD, stroke and T2D. The strength of evidence was classified per the World Cancer Research Fund criteria. RESULTS After screening 23,244 references, we included 42 papers from cohort studies (28 unique cohorts, 1,890,573 participants) and 18 RCTs (2,266 participants). In the cohorts, mainly populations with low consumption, high versus low total nuts/seeds consumption was inversely associated with total CVD (RR 0.81; 95% CI 0.75, 0.86; I 2 = 67%), CVD mortality (0.77; 0.72, 0.82; I 2 = 59.3%), CHD (0.82; 0.76, 0.89; I 2 = 64%), CHD mortality (0.75; 0.65, 0.87; I 2 = 66.9%) and non-fatal CHD (0.85; 0.75, 0.96; I 2 = 62.2%). According to the non-linear dose-response analyses, consumption of 30 g/day of total nuts/seeds was associated with RRs of similar magnitude. For stroke and T2D the summary RR for high versus low intake was 0.91 (95% CI 0.85, 0.97; I 2 = 24.8%) and 0.95 (0.75, 1.21; I 2 = 82.2%). Intake of nuts (median ~50 g/day) lowered total (-0.15 mmol/L; -0.22, -0.08; I 2 = 31.2%) and LDL-cholesterol (-0.13 mmol/L; -0.21, -0.05; I 2 = 68.6%), but not blood pressure. Findings on fasting glucose, HbA1c and insulin resistance were conflicting. The results were robust to sensitivity and subgroup analyses. We rated the associations between nuts/seeds and both CVD and CHD as probable. There was limited but suggestive evidence for no association with stroke. No conclusion could be made for T2D. CONCLUSION There is a probable relationship between consumption of nuts/seeds and lower risk of CVD, mostly driven by CHD, possibly in part through effects on blood lipids. More research on stroke and T2D may affect the conclusions. The evidence of specific nuts should be further investigated.
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Comparative effects of vitamin and mineral supplements in the management of type 2 diabetes in primary care: A systematic review and network meta-analysis of randomized controlled trials.
Xia, J, Yu, J, Xu, H, Zhou, Y, Li, H, Yin, S, Xu, D, Wang, Y, Xia, H, Liao, W, et al
Pharmacological research. 2023;188:106647
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Type 2 diabetes mellitus (T2DM), characterised by sustained hyperglycaemia and insulin resistance, remains a severe driver of chronic metabolic diseases such as cardiovascular diseases. The aim of this study was to investigate and compare the efficacy of vitamin and mineral supplements in the management of glycaemic control and lipid metabolism for type 2 diabetic patients to inform clinical practice. This study is a systematic review and meta-analysis of one hundred and seventy articles with a total of 4223 adults with T2DM. Participants were randomised to either the placebo/no treatment group (n= 6345) or to the treatment group (n= 7878). Results show that: - chromium was the most effective micronutrient for decreasing fasting blood glucose and insulin resistance. - vitamin K was the top-ranked micronutrient in reducing haemoglobin A1C and fasting insulin levels. - vanadium was the top-ranked micronutrient in total cholesterol reductions. - niacin was ranked as the most effective in triglycerides reductions and increasing high-density lipoprotein cholesterol levels. - vitamin E was the top-ranked micronutrient in low-density lipoprotein cholesterol reductions. Authors conclude that micronutrient supplements especially chromium, vitamin E, vitamin K, vanadium, and niacin supplements, may be more effective in the management of T2DM compared with other micronutrients.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Clinicians could consider the adjunctive effect of micronutrients supplements, such as chromium, vitamin E, vitamin K, vanadium, and niacin supplements in a nutrition protocol to manage T2DM and slow or prevent its complications.
- The study authors state that the vitamin and mineral supplements under review had a statistically significant improvement, however they did not reach the study threshold for clinical significance. Therefore they advise caution in utilising micronutrient supplements in the management of glucose and lipid metabolism for T2DM.
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:
Objectives
The aim of this systematic review was to evaluate the comparative effects of vitamin and mineral supplements on managing glycemic control and lipid metabolism for type 2 diabetes mellitus (T2DM).
Methodology
This systematic review is registered with PROSPERO and adhered to PRISMA-2020 guidelines for network meta-analysis
The Cochrane Collaboration’s risk-of-bias tool was used to assess eligible randomised trials
8 prespecified markers identified and assessed in this study : 1) HbA1c (%), 2) fasting blood glucose (mmol/L), 3) total cholesterol (mmol/L), 4) triglycerides (mmol/L), 5) fasting insulin (μIU/mL), 6) HOMA-IR, 7) LDL-c (mmol/L), and 8) HDL-c (mmol/L).
Results
- 170 RCT trials of 14223 participants with T2DM treated with vitamin supplements, mineral supplements, or placebo/no treatment were included
- Low to very low certainty evidence established chromium supplements as the most effective in reducing fasting blood glucose levels and homeostasis model assessment of insulin resistance (SUCRAs: 90.4% and 78.3%, respectively)
- Vitamin K supplements ranked best in reducing glycated haemoglobin A1c and fasting insulin levels (SUCRAs: 97.0% and 82.3%, respectively), with moderate to very low certainty evidence
- Vanadium supplements ranked best in lowering total cholesterol levels with very low evidence certainty (SUCRAs:100%)
- Niacin supplements ranked best in triglyceride reductions and increasing high-density lipo-protein cholesterol levels with low to very low evidence certainty (SUCRAs:93.7% and 94.6%, respectively)
- Vitamin E supplements ranked best in reducing low-density lipoprotein cholesterol levels with very low evidence certainty (SUCRAs:80.0%).
Conclusion
- Micronutrient supplements, such as chromium, vitamin E, vitamin K, vanadium, and niacin supplements, may be efficacious in managing T2DM
- It should be noted that the evidence certainty for all was low.
Clinical practice applications:
- Chromium plays an important role in carbohydrate and lipid metabolism and was the most effective micronutrient for decreasing fasting blood glucose, HbA1c, fasting insulin, and HOMA-IR reductions. More pronounced effects were seen for chromium than vitamin E, vitamin C, niacin, selenium, and magnesium supplements
- Vitamin K was the top-ranked micronutrient in reducing HbA1c and fasting insulin levels. The mechanism through which Vitamin K affects glucose metabolism is proposed as activation of the AMP-activated protein kinase/sirtuin 1, that in turn increases phosphocreatine 3-kinase and glucose transporter 2 to decrease insulin resistance and fasting glucose.
- Vanadium was the top-ranked micronutrient in total cholesterol (TC) reductions, where supplementation dosage should be carefully considered, as vanadium compounds can be moderately or highly toxic. Vanadium supplementation is only recommended in cases of vanadium deficiency or diabetes, hyperlipidemia, and hypertension, where the intake of vanadium from food should be enhanced in preference to supplementation
- Niacin was ranked as the most effective in triglyceride (TG) reductions and increasing HDL cholesterol levels. The dose of niacin could not be determined
- Vitamin E was the top-ranked micronutrient in low-density lipo- protein (LDL) cholesterol reductions.
Considerations for future research:
- Considering the clinical importance of these findings, new research is needed to get better insight into the efficacy of micronutrient supplements in managing T2DM
- Selenium homeostasis, selenoprotein, insulin signaling/secretion, and carbohydrate/lipid metabolism are linked in multiple and complex ways but the authors could not explain why chromium supplementation would lower blood glucose more effectively than selenium supplementation, and suggest more research is needed to clarify this
- While vitamin K status could be an emerging treatment target in T2DM prevention and management, it remains to be determined whether vitamin K supplementation has an advantage over other nutrients in terms of hypoglycemic effect, and further research is necessary
- The beneficial effect of vitamin E and niacin supplements regarding lipid metabolism warrant investigation through more rigorous comparative studies.
Abstract
Medical nutrition treatment can manage diabetes and slow or prevent its complications. The comparative effects of micronutrient supplements, however, have not yet been well established. We aimed at evaluating the comparative effects of vitamin and mineral supplements on managing glycemic control and lipid metabolism for type 2 diabetes mellitus (T2DM) to inform clinical practice. Electronic and hand searches for randomized controlled trials (RCTs) were performed until June 1, 2022. We selected RCTs enrolling patients with T2DM who were treated with vitamin supplements, mineral supplements, or placebo/no treatment. Data were pooled via frequentist random-effects network meta-analyses. A total of 170 eligible trials and 14223 participants were included. Low to very low certainty evidence established chromium supplements as the most effective in reducing fasting blood glucose levels and homeostasis model assessment of insulin resistance (SUCRAs: 90.4% and 78.3%, respectively). Vitamin K supplements ranked best in reducing glycated hemoglobin A1c and fasting insulin levels (SUCRAs: 97.0% and 82.3%, respectively), with moderate to very low certainty evidence. Vanadium supplements ranked best in lowering total cholesterol levels with very low evidence certainty (SUCRAs:100%). Niacin supplements ranked best in triglyceride reductions and increasing high-density lipoprotein cholesterol levels with low to very low evidence certainty (SUCRAs:93.7% and 94.6%, respectively). Vitamin E supplements ranked best in reducing low-density lipoprotein cholesterol levels with very low evidence certainty (SUCRAs:80.0%). Our analyses indicated that micronutrient supplements, especially chromium, vitamin E, vitamin K, vanadium, and niacin supplements, may be more efficacious in managing T2DM than other micronutrients. Considering the clinical importance of these findings, new research is needed to get better insight into this issue.
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Polyphenols as potential metabolism mechanisms regulators in liver protection and liver cancer prevention.
Li, S, Yin, S, Ding, H, Shao, Y, Zhou, S, Pu, W, Han, L, Wang, T, Yu, H
Cell proliferation. 2023;56(1):e13346
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Multiple risk factors could lead to the development of liver cancer, one of the most common malignant tumours in the world. These risk factors include hepatitis infection, non-alcoholic fatty liver disease and excessive alcohol consumption. Polyphenols are bioactive compounds with antioxidant, anti-inflammatory, anti-mutagenic, anti-viral, hypoglycaemic, anti-hypertensive, antibacterial and anti-proliferative properties. Polyphenols may be effective in reducing the risk of developing liver cancer by altering the metabolism. This review evaluated the effectiveness of polyphenols in protecting the liver and inhibiting hepatocarcinoma development. In addition, the review evaluated several mechanisms by which polyphenols affect glucose and lipid metabolism and mitochondrial metabolism and reduce the effects of oxidative stress, inflammation and toxic metabolites. Further robust studies are required to assess the beneficial effects of polyphenols as a therapeutic agent, as the current knowledge is limited. However, healthcare professionals can use the results of this study to understand the protective effects of polyphenols against liver disease.
Abstract
BACKGROUND Liver cancer is one of the common malignancies. The dysregulation of metabolism is a driver of accelerated tumourigenesis. Metabolic changes are well documented to maintain tumour growth, proliferation and survival. Recently, a variety of polyphenols have been shown to have a crucial role both in liver disease prevention and metabolism regulation. METHODS We conducted a literature search and combined recent data with systematic analysis to comprehensively describe the molecular mechanisms that link polyphenols to metabolic regulation and their contribution in liver protection and liver cancer prevention. RESULTS Targeting metabolic dysregulation in organisms prevents and resists the development of liver cancer, which has important implications for identifying new therapeutic strategies for the management and treatment of cancer. Polyphenols are a class of complex compounds composed of multiple phenolic hydroxyl groups and are the main active ingredients of many natural plants. They mediate a broad spectrum of biological and pharmacological functions containing complex lipid metabolism, glucose metabolism, iron metabolism, intestinal flora imbalance, as well as the direct interaction of their metabolites with key cell-signalling proteins. A large number of studies have found that polyphenols affect the metabolism of organisms by interfering with a variety of intracellular signals, thereby protecting the liver and reducing the risk of liver cancer. CONCLUSION This review systematically illustrates that various polyphenols, including resveratrol, chlorogenic acid, caffeic acid, dihydromyricetin, quercetin, catechins, curcumin, etc., improve metabolic disorders through direct or indirect pathways to protect the liver and fight liver cancer.
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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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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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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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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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The Effect of Resveratrol on Blood Lipid Profile: A Dose-Response Meta-Analysis of Randomized Controlled Trials.
Cao, X, Liao, W, Xia, H, Wang, S, Sun, G
Nutrients. 2022;14(18)
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It is well known that cardiovascular disease is a leading cause of death. Imbalances in the blood lipid levels, such as elevation of total cholesterol, Triglycerides and LDL cholesterol, may increase the risk of cardiovascular disease. It has been shown that resveratrol, a polyphenol found in grapes, blueberries, mulberries, raspberries, peanuts, and knotweeds, has protective effects against cardiovascular disease. In this meta-analysis, 17 randomised controlled trials were included, with varying durations of 4 to 48 weeks and intervention dosages ranging from 10 to 3000 mg/day. According to the results of this meta-analysis, Resveratrol supplementation significantly reduced total cholesterol, triglycerides, and LDL cholesterol, but not HDL cholesterol. In addition, the reduction in LDL cholesterol was more significant in type 2 diabetic patients when resveratrol was supplemented for 12 weeks or more. A crucial factor in determining the effectiveness of resveratrol supplementation is its dosage. High doses over 500 mg/day were found to have the opposite effect of increasing body mass index and body weight and suppressing the cardioprotective effect. The effects of different dosages and durations of resveratrol supplementation on cardiometabolic health require further robust research. Healthcare professionals may use the results of this study to understand the importance of careful consideration when supplementing resveratrol as a nutraceutical.
Abstract
(1) Background: The effects of resveratrol on blood lipids are controversial. Whether there is a dose-response of the lipid profile upon resveratrol supplementation is unknown. (2) Methods: This dose-response meta-analysis of randomized controlled trials (RCTs) was performed to explore the effects of resveratrol supplementation on lipid profile. A systematical and comprehensive search of several databases was conducted by 30 June 2022. (3) Results: The results indicated that the intake of resveratrol could significantly decrease the total cholesterol (TC) (mean difference = -10.28; 95%CI: -13.79, -6.76, p < 0.001), triglyceride (TG) (Mean difference = -856; 95%CI: -12.37, -4.75, p < 0.001) and low-density lipoprotein cholesterol (LDL-C) (mean difference = -5.69; 95%CI: -11.07, -0.31, p = 0.038) level, but did not alter the level of high-density lipoprotein cholesterol (HDL-C). In the non-linear dose-response analysis, we observed a significant effect of the supplementation dosage on the level of LDL-C (p-nonlinearity = 0.002). Results from the sub-group analysis showed that the reduction of LDL-C was more significant in the trials with a duration of ≥12 weeks and in subjects with type 2 diabetes mellitus. (4) Conclusion: Findings from this study suggest that resveratrol may be beneficial to reduce TC, TG, and LDL-C levels in the blood. The dosage of the resveratrol intervention is an essential factor that affects the level of LDL-C.
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Polyphenol Intake in Pregnant Women on Gestational Diabetes Risk and Neurodevelopmental Disorders in Offspring: A Systematic Review.
Salinas-Roca, B, Rubió-Piqué, L, Montull-López, A
Nutrients. 2022;14(18)
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In Europe, gestational diabetes affects approximately 10.9% of pregnant women. According to previous research, the cardiometabolic health of the mother and the mother's dietary habits during pregnancy may affect the foetus' neurodevelopment. Taking polyphenol supplements and eating foods rich in polyphenols is beneficial for promoting health across generations. In this systematic review, fourteen studies were included in order to evaluate the effects of polyphenols on gestational diabetes and mental health in the offspring. A higher prevalence of neurodevelopmental diseases in offspring is associated with gestational diabetes. The results of this systematic review revealed that polyphenol intake during pregnancy might have a beneficial effect on improving cardiometabolic health, reducing inflammation, DNA methylation and oxidative stress, thus reducing the risk of developing fetal neurodevelopmental disorders, such as attention deficit hyperactivity disorder, autism spectrum disorder and learning disorders. There is a need for further robust research, as the existing evidence regarding the safety of long-term polyphenol supplementation and its effects on gestational diabetes and fetal neurodevelopment is very limited. In spite of this, healthcare professionals can use the findings of this systematic review to learn more about the positive health benefits of polyphenols in pregnant women.
Abstract
The intake of foods containing polyphenols can have a protective role to avoid comorbidities during pregnancy and, at the same time, promote transgenerational health. This review aims to describe the effect of polyphenol intake through supplements or polyphenol-rich foods during pregnancy on the incidence and evolution of gestational diabetes mellitus (GDM), as well as the link with the neurodevelopment of the fetus. Using PRISMA procedures, a systematic review was conducted by searching in biomedical databases (PubMed, Cinahl and Scopus) from January to June 2022. Full articles were screened (n = 419) and critically appraised. Fourteen studies were selected and were divided into two different thematic blocks considering (i) the effect of polyphenols in GDM and (ii) the effect of GDM to mental disorders in the offspring. A positive relationship was observed between the intake of polyphenols and the prevention and control of cardiometabolic complications during pregnancy, such as GDM, which could be related to thwarted inflammatory and oxidative processes, as well as neuronal factors. GDM is related to a greater risk of suffering from diseases related to neurodevelopment, such as attention deficit hyperactivity disorder, autism spectrum disorder and learning disorder. Further clinical research on the molecule protective mechanism of polyphenols on pregnant women is required to understand the transgenerational impact on fetal neurodevelopment.
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Nutritional intervention for diabetes mellitus with Alzheimer's disease.
Li, Z, Li, S, Xiao, Y, Zhong, T, Yu, X, Wang, L
Frontiers in nutrition. 2022;9:1046726
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Diabetes Mellitus (DM) affects more than 463 million people worldwide. Similarly, the number of deaths related to Alzheimer’s disease (AD) has increased by 145%. There are several common risk factors for Type 2 Diabetes and AD, including obesity, insulin resistance, and ageing, as well as common pathological mechanisms, including altered insulin signalling, oxidative stress, neuroinflammation, mitochondrial dysfunction, formation of glycated proteins and metabolic syndrome. This review aims to summarize the therapeutic effects of different nutritional therapy strategies on the reduction of DM and AD risk. Controlling blood sugar levels and reducing calorie intake is crucial to preventing diabetes and Alzheimer's disease. The low-carbohydrate, ketogenic, and Mediterranean diets have been found to improve glucose control in people with Type 2 diabetes (T2D). In addition, MIND (Mediterranean-DASH Diet Intervention for Neurodegenerative Delay) and a ketogenic diet may improve cognition in AD patients. Lactobacillus, Bifidobacterium probiotics, and prebiotics, such as inulin, may inhibit the progression of T2D and AD diseases by suppressing inflammation and modulating gut microbes. In addition, vitamins A, C, D, E, B6, B12, folate, long-chain polyunsaturated fatty acids, zinc, magnesium, and polyphenols may improve cognitive decline, homocysteine levels, and insulin resistance in AD and T2D patients. Healthcare professionals can use the results of this review to understand the beneficial effects of dietary strategies and multi-nutrient supplementation on DM and AD. However, further robust studies are required to investigate the risk factors and underlying mechanisms behind DM-combined AD progression.
Abstract
The combined disease burden of diabetes mellitus (DM) and Alzheimer's disease (AD) is increasing, and the two diseases share some common pathological changes. However, the pharmacotherapeutic approach to this clinical complexity is limited to symptomatic rather than disease-arresting, with the possible exception of metformin. Whether nutritional intervention might extend or synergize with these effects of metformin is of interest. In particular, dietary patterns with an emphasis on dietary diversity shown to affect cognitive function are of growing interest in a range of food cultural settings. This paper presents the association between diabetes and AD. In addition, the cross-cultural nutritional intervention programs with the potential to mitigate both insulin resistance (IR) and hyperglycemia, together with cognitive impairment are also reviewed. Both dietary patterns and nutritional supplementation showed the effects of improving glycemic control and reducing cognitive decline in diabetes associated with AD, but the intervention specificity remained controversial. Multi-nutrient supplements combined with diverse diets may have preventive and therapeutic potential for DM combined with AD, at least as related to the B vitamin group and folate-dependent homocysteine (Hcy). The nutritional intervention has promise in the prevention and management of DM and AD comorbidities, and more clinical studies would be of nutritional scientific merit.
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Exploring the Therapeutic Potential of Phytochemicals in Alzheimer's Disease: Focus on Polyphenols and Monoterpenes.
Piccialli, I, Tedeschi, V, Caputo, L, D'Errico, S, Ciccone, R, De Feo, V, Secondo, A, Pannaccione, A
Frontiers in pharmacology. 2022;13:876614
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Alzheimer’s disease (AD) is a complex chronic neurodegenerative disorder characterized by the irreversible loss of memory and brain functions. Many different hypotheses are circulating to explain the underlying cause of the disease, yet therapeutic strategies to treat the degenerative processes have been unsuccessful to date. In recent years research has broadened its focus, viewing the pathology of AD more as an interplay of many factors whilst also taking into account other comorbidities associated with AD, such as insulin resistance and low energy production in the brain. One of the big challenges for clinical treatment is that by the time symptoms present and the diagnosis is made, irreversible brain loss has already occurred. Many lifestyle interventions can influence the modifiable risk factors of ageing and hence present a promising preventative strategy for AD. Plant-derived compounds found in foods and medicinal herbs have received much interest due to their versatile action potential. This review specifically looked at compounds in the polyphenols and monoterpenes category and summarized the current evidence, possible mechanisms of action and how this could aid AD management. An overview of the various hypothesis believed to contribute to the development of AD is presented. These include Aβ aggregation and toxicity, Tau hyperphosphorylation and toxicity, oxidative stress and mitochondrial dysfunction, neuroinflammation and brain insulin resistance. A synopsis of the current state of treatments and treatment development is provided, before exploring the potential of plant-derived compounds, in particular polyphenols and monoterpenes and their potential from various sources. Concluding remarks discuss the challenges that come with turning plant-derived compounds into drug treatments. Many studies on mechanisms of action show therapeutic potential, clinical trials in humans have not yet managed to mirror those effects sufficiently. There is a need to advance the field further and assess more thoroughly the clinical relevance of these findings. This review yields a comprehensive and detailed summary of aspects of AD, the proposed mechanisms and the potential of some nutrition related management options.
Abstract
Alzheimer's disease (AD) is a chronic, complex neurodegenerative disorder mainly characterized by the irreversible loss of memory and cognitive functions. Different hypotheses have been proposed thus far to explain the etiology of this devastating disorder, including those centered on the Amyloid-β (Aβ) peptide aggregation, Tau hyperphosphorylation, neuroinflammation and oxidative stress. Nonetheless, the therapeutic strategies conceived thus far to treat AD neurodegeneration have proven unsuccessful, probably due to the use of single-target drugs unable to arrest the progressive deterioration of brain functions. For this reason, the theoretical description of the AD etiology has recently switched from over-emphasizing a single deleterious process to considering AD neurodegeneration as the result of different pathogenic mechanisms and their interplay. Moreover, much relevance has recently been conferred to several comorbidities inducing insulin resistance and brain energy hypometabolism, including diabetes and obesity. As consequence, much interest is currently accorded in AD treatment to a multi-target approach interfering with different pathways at the same time, and to life-style interventions aimed at preventing the modifiable risk-factors strictly associated with aging. In this context, phytochemical compounds are emerging as an enormous source to draw on in the search for multi-target agents completing or assisting the traditional pharmacological medicine. Intriguingly, many plant-derived compounds have proven their efficacy in counteracting several pathogenic processes such as the Aβ aggregation, neuroinflammation, oxidative stress and insulin resistance. Many strategies have also been conceived to overcome the limitations of some promising phytochemicals related to their poor pharmacokinetic profiles, including nanotechnology and synthetic routes. Considering the emerging therapeutic potential of natural medicine, the aim of the present review is therefore to highlight the most promising phytochemical compounds belonging to two major classes, polyphenols and monoterpenes, and to report the main findings about their mechanisms of action relating to the AD pathogenesis.
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Astaxanthin Influence on Health Outcomes of Adults at Risk of Metabolic Syndrome: A Systematic Review and Meta-Analysis.
Leung, LY, Chan, SM, Tam, HL, Wong, ES
Nutrients. 2022;14(10)
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Metabolic syndrome is a term used to describe a combination of three or more health issues that can increase the risk of cardiovascular disease by 70%. Risk factors include hypertension, hyperglycaemia, obesity, and dyslipidaemia. Astaxanthin is a powerful antioxidant that can potentially reduce the risk of metabolic syndrome. This systematic review and meta-analysis included seven double-blinded randomised controlled trials that evaluated the beneficial effects of Astaxanthin in reducing the risk factors associated with metabolic syndrome. More than eight weeks of daily ≤6 mg Astaxanthin supplementation significantly reduced systolic blood pressure, total cholesterol, triglycerides, and LDL cholesterol. The therapeutic value of Astaxanthin supplementation requires long-term robust research since studies included in this study are highly heterogeneous in terms of the intervention period, the dosage of the supplements, participant health, and sample size. This study can assist healthcare professionals in understanding the beneficial effects of Astaxanthin supplements on people with metabolic syndrome.
Abstract
The use of medication is effective in managing metabolic syndrome (MetS), but side effects have led to increased attention on using nutraceuticals and supplements. Astaxanthin shows positive effects in reducing the risk of MetS, but results from individual studies are inconclusive. This systematic review summarizes the latest evidence of astaxanthin in adults with risk factors of MetS. A systematic search of English and Chinese randomized controlled trials in 14 electronic databases from inception to 30 June 2021 was performed. Two reviewers independently screened the titles and abstracts, and conducted full-text review, quality appraisal, and extraction of data. Risk of bias was assessed by PEDro. A total of 7 studies met the inclusion criteria with 321 participants. Six studies were rated to have excellent methodological quality, while the remaining one was rated at good. Results show marginal effects of astaxanthin on reduction in total cholesterol and systolic blood pressure, and a significant attenuating effect on low-density lipoprotein cholesterol. Further robust evidence is needed to examine the effects of astaxanthin in adults at risk of MetS.