Nutrition and health

Objectives:
Is there a causal relationship between tomato consumption and lowering effects on cholesterol, triglycerides or fasting blood sugar levels?
 
Study design:
This review article included 6 RCTs.

Results and conclusions:
The investigators found tomato consumption significantly reduced total plasma cholesterol levels [WMD = -4.39 mg/dL, 95% CI = -7.09 to -1.68, I2 = 48%, p = 0.05].

The investigators found tomato consumption significantly reduced plasma triglyceride (TG) levels [WMD = -3.94 mg/dL, 95% CI = -7.67 to -0.21, I2 = 90%, p = 0.001].
A higher reduction effect was found on younger participants.

The investigators found tomato consumption significantly reduced plasma LDL cholesterol (bad cholesterol) levels [WMD = -2.09 mg/dL, 95% CI = -3.73 to -0.81, I2 = 78%, p = 0.001].
A higher reduction effect was found on younger participants.

The investigators found tomato consumption significantly increased plasma HDL cholesterol (good cholesterol) levels [WMD = 2.25 mg/dL, 95% CI = 0.41 to 4.10, I2 = 97%, p = 0.001].

The investigators found tomato consumption had no significant effect on plasma fasting blood sugar levels [WMD = 0.59 mg/dL, 95% CI = -0.28 to 1.46, I2 = 95%, p = 0.001].

The investigators concluded that tomato consumption increases plasma HDL cholesterol (good cholesterol) levels and decreases plasma total cholesterol, LDL cholesterol (bad cholesterol) and triglyceride levels.

Original title:
Effect of Tomato Consumption on Fasting Blood Glucose and Lipid Profiles: A Systematic Review and Meta-Analysis of Randomized Controlled Trials by Li H, Chen, A, [...],Yin X.

Link:
https://pubmed.ncbi.nlm.nih.gov/32243013/

Additional information of El Mondo:
Find more information/studies on tomato consumption and lowering of cholesterol levels right here.

Patients with heart disease often have high LDL cholesterol, low HDL cholesterol and high triglycerides levels.

Objectives:
Do dietary calcium intakes or calcium supplements increase risk of cardiovascular disease?
 
Study design:
This review article included 26 prospective cohort studies and 16 RCTs.

Results and conclusions:
The investigators found in cohort studies that dietary calcium intakes ranging from 200 to 1500 mg/d did not affect the risk of cardiovascular disease [relative risk = 0.96, 95% CI = 0.87 to 1.05].

The investigators found in cohort studies that dietary calcium intakes ranging from 200 to 1500 mg/d did not affect the risk of coronary heart disease [relative risk = 0.98, 95% CI = 0.88 to 1.08].

The investigators found in cohort studies that dietary calcium intakes ranging from 200 to 1500 mg/d did not affect the risk of stroke [relative risk = 0.94, 95% CI = 0.85 to 1.04].

The investigators found in RCTs that calcium supplements significantly increased risk of coronary heart disease with 20% [relative risk = 1.20, 95% CI = 1.08 to 1.33, I2 = 0.0%].

The investigators found in RCTs that calcium supplements significantly increased risk of myocardial infarction with 21% [relative risk = 1.21, 95% CI = 1.08 to 1.35, I2 = 0.0%].

The investigators concluded that 200-1500 mg/d calcium intake from dietary sources do not increase the risk of cardiovascular disease, including coronary heart disease and stroke, while calcium supplements increase coronary heart disease risk, especially myocardial infarction.

Original title:
The Evidence and Controversy Between Dietary Calcium Intake and Calcium Supplementation and the Risk of Cardiovascular Disease: A Systematic Review and Meta-Analysis of Cohort Studies and Randomized Controlled Trials by Yang C, Shi X, […], Sun G.

Link:
https://pubmed.ncbi.nlm.nih.gov/31625814/

Additional information of El Mondo:
Find more information/studies on calcium and lowering of blood pressure right here.

Objectives:
Is there a causal relationship between daily egg consumption and positive effects on blood pressure?
 
Study design:
This review article included 15 RCTs with a total of 748 participants and mean age range from 23.3 to 67.1 years old.

All included studies used whole egg as an intervention which varied from one egg/day to three eggs/day and duration of supplementation ranged from 3 to 12 weeks.

No evidence of publication bias was seen in the meta-analyse (review article) of systolic blood pressure [Begg’s p = 0.235, Eggers’s p = 0.433] and diastolic blood pressure [Begg’s p = 0.254, Eggers’s p = 0.267].

No heterogeneity was found among included studies.

Results and conclusions:
The investigators found, overall, egg consumption had no significant effect on systolic blood pressure [WMD = 0.046 mmHg, 95% CI = - 0.792 to 0.884, p = 0.914, I2 = 0.0%, p = 0.453] and diastolic blood pressure [WMD = -0.603 mmHg, 95% CI = -1.521 to 0.315, p = 0.198, I2 = 38.1%, p = 0.067].
Subgroup analyses had no effect on pooled results.
Sensitivity analysis indicated that excluding each trial did not significantly change the overall observed effects of egg consumption.

The investigators found nonlinear dose-response meta-analysis did not reveal a significant effect of egg consumption [p-nonlinearity = 0.76] and study duration on diastolic blood pressure [p-nonlinearity = 0.63].

The investigators found subgroup analyses based on study design, sex, population health status, obesity and hypertension status, diet adherence, study duration and amount of egg consumption did not affect the overall effects of egg consumption on systolic blood pressure and diastolic blood pressure values.

The investigators concluded that 1-3 eggs/day during 3 to 12 weeks have no effect on blood pressure. However, high-quality RCTs with longer durations are needed to further confirm the effects of egg consumption on blood pressure.

Original title:
Effect of Egg Consumption on Blood Pressure: a Systematic Review and Meta-analysis of Randomized Clinical Trials by Kolahdouz-Mohammadi R, Malekahmadi M, […], Soltani S.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7189334/

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Find more information/studies on causal relationship/significantly, egg consumption and lowering of blood pressure right here.

Objectives:
Does high magnesium dietary intake reduce risk of type 2 diabetes and stroke?

Study design:
This review article included 53 prospective cohort studies with a total of 1,912,634 participants and 76,678 cases (persons with type 2 diabetes or stroke).

Participants were predominately middle aged at baseline (at the beginning of the studies), with a mean magnesium intake of 370 mg/day for the highest category and 232 mg/day for the lowest category.

The mean duration of all eligible studies was 10.7 years.

Results and conclusions:
The investigators found, when comparing the highest category of magnesium dietary intake (370 mg/day) to the lowest (232 mg/day), a significantly reduced risk of 22% [RR = 0.78, 95% CI = 0.75 to 0.81, p 0.001, I2 = 35.6%, p = 0.021] for type 2 diabetes.

The investigators found, when comparing the highest category of magnesium dietary intake (370 mg/day) to the lowest (232 mg/day), a significantly reduced risk of 11% [RR = 0.89, 95% CI = 0.83 to 0.94, p 0.001, I2 = 0%, p = 0.529] for total stroke.

The investigators found, when comparing the highest category of magnesium dietary intake (370 mg/day) to the lowest (232 mg/day), a significantly reduced risk of 12% [RR = 0.88, 95% CI = 0.81 to 0.95, p = 0.001, I2 = 16.9%, p = 0.265] for ischaemic stroke.

The investigators found in studies adjusted for cereal fiber dietary intake, a significantly reduced risk of 21% [RR = 0.79, 95% CI = 0.73 to 0.85, p 0.001] for type 2 diabetes.

The investigators found in studies adjusted for calcium dietary intake, a significantly reduced risk of 11% [RR = 0.89, 95% CI = 0.80 to 0.99, p = 0.040] for total stroke.

The investigators found in stratified analyses by characteristics of the population and study design, a significantly reduced risk of 9% [RR = 0.91, 95% CI = 0.83 to 0.99] for total stroke among female.

The investigators found in stratified analyses by characteristics of the population and study design, a significantly reduced risk of 11% [RR = 0.89, 95% CI = 0.79 to 1.00] for ischaemic stroke among female.

The investigators found in stratified analyses by characteristics of the population and study design, a significantly reduced risk of 11% [RR = 0.89, 95% CI = 0.82 to 0.96] for total stroke among individuals with BMI ≥25 kg/m².

The investigators found in stratified analyses by characteristics of the population and study design, a significantly reduced risk of 12% [RR = 0.88, 95% CI = 0.81 to 0.96] for ischaemic stroke among individuals with BMI ≥25 kg/m².

The investigators found in stratified analyses by characteristics of the population and study design, a significantly reduced risk of 11% [RR = 0.89, 95% CI = 0.83 to 0.95] for total stroke among studies wtith ≥12-year follow-up.

The investigators found in stratified analyses by characteristics of the population and study design, a significantly reduced risk of 12% [RR = 0.88, 95% CI = 0.81 to 0.95] for ischaemic stroke among studies wtith ≥12-year follow-up.

The investigators found for every 100 mg/day increment of magnesium dietary intake, a significantly reduced risk of 6% [RR = 0.94, 95% CI = 0.93 to 0.95] for type 2 diabetes.

The investigators found for every 100 mg/day increment of magnesium dietary intake, a significantly reduced risk of 2% [RR = 0.98, 95% CI = 0.97 to 0.99] for total stroke.

The investigators found for every 100 mg/day increment of magnesium dietary intake, a significantly reduced risk of 2% [RR = 0.98, 95% CI = 0.97 to 0.99] for ischaemic stroke.

The investigators concluded magnesium dietary intake has a substantial inverse association with type 2 diabetes and (total/ ischaemic) stroke. Furthermore, female, participants with obesity (BMI ≥ 25 kg/m²) and with a longer follow-up period (≥12 years) obtain greater benefit from magnesium intake with a lower risk of total and ischaemic stroke incidence. Overall, these findings support the guidelines to address the role of magnesium dietary intake in early prevention strategies to combat type 2 diabetes and stroke. However, additional RCTs are needed in the future to validate the causality.

Original title:
Association of magnesium intake with type 2 diabetes and total stroke: an updated systematic review and meta-analysis by Zhao B, Zeng L, [...], Zhang W.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7103847/

Additional information of El Mondo:
Find more information/studies magnesium consumption, stroke and diabetes right here.

Objectives:
Does Alzheimer disease increase risk of stroke?

Study design:
This review article included 8 studies, representing 121,719 individuals (Alzheimer disease = 73,044 and non-Alzheimer disease = 48,675).

Results and conclusions:
The investigators found patients with Alzheimer disease had a significantly increased risk of 42% [relative risk = 1.42, 95% CI = 1.23 to 1.64] for hemorrhagic stroke.

The investigators concluded Alzheimer disease increases risk of hemorrhagic stroke.

Original title:
Risk of hemorrhagic and ischemic stroke in patients with Alzheimer disease: A synthesis of the literature by Waziry R, Chibnik LB, […], Hofman A.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31949087

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Find more information/studies on Alzheimer disease right here.

Objectives:
Is there a causal relationship between strawberry consumption and positive effects on cardiovascular risk factors?
 
Study design:
This review article included 11 RCTs (6 for blood pressure, 7 for lipid profile, 7 for fasting blood glucose and 6 for C-reactive protein).

There was little evidence of heterogeneity in the analysis and no evidence of publication bias.

Results and conclusions:
The investigators found overall, strawberry consumption significantly reduced C-reactive protein (CRP) levels by 0.63 mg/L [95% CI = -1.04 to -0.22] but did not affect blood pressure, lipid profile or fasting blood glucose in the main analyses.

The investigators found stratified by baseline endpoint levels, that strawberry consumption significantly reduced total cholesterol levels among people with baseline levels >5 mmol/L [-0.52 mmol/L, 95% CI = -088 to -0.15] and reduced LDL-cholesterol levels among people with baseline levels >3 mmol/L [-0.31 mmol/L, 95% CI = -0.60 to -0.02].

The investigators concluded strawberry consumption reduces C-reactive protein (CRP) levels and improves total cholesterol and LDL-cholesterol (bad cholesterol) in individuals with high baseline levels (level at the beginning of the study).

Original title:
Effects of strawberry intervention on cardiovascular risk factors: a meta-analysis of randomized controlled trials by Gao Q, Qin LQ, […], Dong JY.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32238201

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Find more information/studies on fruit consumption and lowering of cholesterol levels right here.

Objectives:
Is there an association between total meat, red meat, processed meat, poultry and fish intake and risk of type 2 diabetes (T2D)?

Study design:
This review article included 28 prospective cohort studies.

Results and conclusions:
The investigators found when compared with the lowest category, the highest category of total meat intake, significantly increased risk of type 2 diabetes with 33% [summary relative risk = 1.33, 95% CI = 1.16 to 1.52].
Significantly means that there is an association with a 95% confidence.

The investigators found when compared with the lowest category, the highest category of red meat intake, significantly increased risk of type 2 diabetes with 22% [summary relative risk = 1.22, 95% CI = 1.16 to 1.28].
Significantly because summary relative risk of 1 was not found in the 95% CI of 1.16 to 1.28. Summary relative risk of 1 means no risk/association.

The investigators found when compared with the lowest category, the highest category of processed meat intake, significantly increased risk of type 2 diabetes with 25% [summary relative risk = 1.25, 95% CI = 1.13 to 1.37].
Significantly means it can be said with a 95% confidence that the highest category of processed meat intake really increased risk of type 2 diabetes with 25%.

The investigators found no association between highest category of poultry intake and risk of type 2 diabetes [summary relative risk = 1.00, 95% CI = 0.93 to 1.07].
No association because summary relative risk of 1 was found in the 95% CI of 0.93 to 1.07. Summary relative risk of 1 means no risk/association.

The investigators found no association between highest category of fish intake and risk of type 2 diabetes [summary relative risk = 1.01, 95% CI = 0.93 to 1.10].

The investigators found in the dose-response analysis, each additional 100g/day of total and red meat and 50g/day of processed meat, were found to be associated with a 36% [95% CI = 1.23 to 1.49], 31% [95% CI = 1.19 to 1.45] and 46% [95% CI = 1.26 to 1.69] increased risk of type 2 diabetes, respectively.

The investigators found, in addition, there was evidence of a non-linear dose-response association between processed meat and type 2 diabetes [p = 0.004], with the risk increasing by 30% with increasing intakes up to 30g/day.

The investigators concluded 100g/day of total meat, 100g/day red meat and 50g/day of processed meat, increase risk of type 2 diabetes.

Original title:
Meat and fish intake and type 2 diabetes: dose-response meta-analysis of prospective cohort studies by Yang X, Li Y, […], Li L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32302686

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Find more information/studies on fish and meat consumption and diabetes right here.

Objectives:
Does fish consumption decrease risk of cardiovascular disease, depression, mortality and cancer?
 
Study design:
This review article included a total of 34 meta-analyses of prospective observational studies, reporting summary relative risks (SRR) for 40 different outcomes obtained from 298 primary prospective cohort studies.

The summary relative risk (SRR) for each meta-analysis was recalculated by using a random-effects model.

Results and conclusions:
The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 8% lower risk of all-cause mortality [SRR = 0.92, 95% CI = 0.87 to 0.97].

The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 25% lower risk of cardiovascular mortality [SRR = 0.75, 95% CI = 0.65 to 0.87].

The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 12% lower risk of coronary heart disease [SRR = 0.88, 95% CI = 0.79 to 0.99].

The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 25% lower risk of myocardial infarction [SRR = 0.75, 95% CI = 0.65 to 0.93].

The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 14% lower risk of stroke [SRR = 0.86, 95% CI = 0.75 to 0.99].

The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 20% lower risk of heart failure [SRR = 0.80, 95% CI = 0.67 to 0.95].

The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 12% lower risk of depression [SRR = 0.88, 95% CI = 0.79 to 0.98].

The investigators found moderate-quality evidence showed that each 100-g/d increment in fish consumption was associated with a 35% lower risk of liver cancer [SRR = 0.65, 95% CI = 0.48 to 0.87].

The investigators concluded evidence of moderate quality shows that 100-g/d fish consumption is associated with a lower risk of cardiovascular disease, depression, mortality and liver cancer and therefore, can be considered as a healthy animal-based dietary source of protein. Further research is needed for outcomes for which the quality of the evidence was rated low and very low, considering types of fish consumed, different methods of cooking fish and all potential confounding variables.

Original title:
Fish Consumption and the Risk of Chronic Disease: An Umbrella Review of Meta-Analyses of Prospective Cohort Studies by Jayedi A and Shab-Bidar S.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32207773

Additional information of El Mondo:
Find more information/studies on fish consumption, cancer and cardiovascular disease right here.

Objectives:
Do fermented dairy foods and probiotics supplementation improve risk factors (such as metabolic syndrome, type 2 diabetes, cholesterol) of cardiovascular diseases?

Study design:
This review article included 20 prospective cohort studies and 52 RCTs.

Results and conclusions:
The investigators found in prospective cohort studies, that fermented milk was associated with a 4% reduction in risk of stroke, ischemic heart disease and cardiovascular mortality [RR = 0.96, 95% CI = 0.94 to 0.98].

The investigators found in prospective cohort studies, that yogurt intake was associated with a risk reduction of 27% [RR = 0.73, 95% CI = 0.70 to 0.76] for type 2 diabetes.

The investigators found in prospective cohort studies, that yogurt intake was associated with a risk reduction of 20% [RR = 0.80, 95% CI = 0.74 to 0.87] for metabolic syndrome development.

The investigators found in RCTs, that probiotic supplementation added into dairy matrices produced a greater reduction in lipid biomarkers than when added into capsules/powder in hypercholesterolemic subjects.

The investigators found in RCTs, that probiotic supplementation by capsules/powder produced a greater reduction in type 2 diabetes biomarkers than when added into dairy matrices in diabetic subjects.

The investigators found in RCTs, that probiotic supplementation by both treatments (dairy matrix and capsules/powder) resulted in a significant reduction in anthropometric parameters in obese subjects.

The investigators concluded fermented milk consumption is associated with reduced cardiovascular risk, while yogurt intake is associated with a reduced risk of type 2 diabetes and metabolic syndrome development in the general population. Furthermore, probiotic supplementation added into dairy matrices is beneficial for lowering lipid concentrations and reduce anthropometric parameters. Additionally, probiotic capsule/powder supplementation contributes to type 2 diabetes management and reduces anthropometric parameters. However, these results should be interpreted with caution due to the heterogeneity of the studies and the different probiotic strains used in the studies.

Original title:
Fermented Dairy Products, Probiotic Supplementation, and Cardiometabolic Diseases: A Systematic Review and Meta-analysis by Companys J, Pla-Pagà L, […], Valls RM.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32277831

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Find more information/studies on probiotic, diabetes, overweight and cardiovascular disease right here.

Objectives:
Does tea consumption decrease risk of cardiovascular disease and all-cause mortality among adults?
 
Study design:
This review article included 39 prospective cohort studies.

Strength of evidence was rated as low and moderate (depending on study population age group) for cardiovascular disease-specific mortality outcome and was rated as low for cardiovascular disease events, stroke and all-cause mortality outcomes.

Results and conclusions:
The investigators found linear meta-regression showed that each cup (236.6 mL) increase in daily tea consumption (estimated 280 mg and 338 mg total flavonoids/d for black and green tea, respectively) was associated with an average 4% lower risk of cardiovascular disease mortality, a 2% lower risk of cardiovascular disease events, a 4% lower risk of stroke and a 1.5% lower risk of all-cause mortality.

The investigators found subgroup meta-analysis showed that each cup (236.6 mL) increase in daily tea consumption (estimated 280 mg and 338 mg total flavonoids/d for black and green tea, respectively) was associated with a 11% [pooled adjusted RR = 0.89, 95% CI = 0.83 to 0.96, p = 0.001, I2 = 72.4%, n = 4] lower risk of cardiovascular disease mortality in elderly individuals.

The investigators found subgroup meta-analysis showed that each cup (236.6 mL) increase in daily tea consumption (estimated 280 mg and 338 mg total flavonoids/d for black and green tea, respectively) was associated with a 8% [pooled adjusted RR = 0.92, 95% CI = 0.90 to 0.94, p 0.0001, I2 = 0.3%, n = 3] lower risk of all-cause mortality in elderly individuals.

The investigators found, generally, studies with higher risk of bias appeared to show larger magnitudes of associations than studies with lower risk of bias.

The investigators concluded that daily a cup (236.6 mL) of tea (estimated 280 mg and 338 mg total flavonoids/d for black and green tea, respectively) is associated with a lower risk of cardiovascular disease and all-cause mortality among elderly individuals.

Original title:
Dose-Response Relation between Tea Consumption and Risk of Cardiovascular Disease and All-Cause Mortality: A Systematic Review and Meta-Analysis of Population-Based Studies by Chung M, Zhao N, […], Wallace TC.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32073596

Additional information of El Mondo:
Find more information/studies on tea consumption and cardiovascular disease right here.

Objectives:
Does flaxseed supplementation decrease plasma lipoprotein(a) levels?

Study design:
This review article included 7 RCTs with 629 individuals.

Results and conclusions:
The investigators found flaxseed supplementation significantly reduced plasma lipoprotein(a) levels [MD = -2.06 mg/dL, 95% CI = -3.846 to -0.274, p = 0.024, I2 = 0%, p = 0.986].

The investigators found subgroup analysis also revealed that longer duration only showed significant lowering effect of flaxseed supplementation on plasma lipoprotein(a) levels.

The investigators concluded that long duration of flaxseed supplementation decreases plasma lipoprotein(a) levels. However, future well-designed and long-term clinical trials are required to confirm these results.

Original title:
Impact of flaxseed supplementation on plasma lipoprotein(a) concentrations: A systematic review and meta-analysis of randomized controlled trials by Hadi A, Askarpour M, […], Ghavami A.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32073724

Additional information of El Mondo:
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Lipoprotein(a) is a risk factor for atherosclerosis and related diseases, such as coronary heart disease and stroke.

 

Objectives:
Vitamin C as a supplement to treat hypertension has been proposed. However, it remains controversial whether vitamin C can improve blood pressure in patients with primary hypertension. Therefore, this review article has been conducted.

Do vitamin C supplements reduce blood pressure in patients with primary hypertension?

Study design:
This review article included 8 RCTs involving 614 participants.
There was no publication bias.

Results and conclusions:
The investigators found vitamin C supplements significantly reduced systolic blood pressure in patients with essential hypertension [WMD  = -4.09, 95% CI = -5.56 to -2.62, p 0 .001, I2  =  35%, p = 0.15].

The investigators found vitamin C supplements significantly reduced diastolic blood pressure in patients with essential hypertension [WMD  = -2.30, 95% CI = -4.27 to -0.331, p  = 0 .02, I2 = 75%, p = 0 .0002].

The investigators found vitamin C supplements significantly reduced systolic blood pressure for the subgroup with an age ≥60 years and that with ≥35 participants [WMD = -3.75, 95% CI = -6.24 to -1.26, p  = 0 .003].

The investigators found vitamin C supplements significantly reduced diastolic blood pressure for the subgroup with an age ≥60 years and that with ≥35 participants [WMD = -3.29, 95% CI = -5.98 to -0.60, p  = 0 .02].

The investigators found in the subgroup analysis that vitamin C supplements during ≥6 weeks significantly reduced systolic blood pressure in patients with essential hypertension [WMD = -4.77, 95% CI = -6.46 to -3.08, p   0 .001].

The investigators found in the subgroup analysis that ≥500 mg/d vitamin C supplements significantly reduced systolic blood pressure in patients with essential hypertension [WMD  =  -5.01, 95% CI = -8.55 to -1.48, p  = 0.005, I2  =  44%, p =  0.13].

The investigators concluded ≥500 mg/d vitamin C supplements during ≥6 weeks reduce blood pressure in patients with primary hypertension. However, in view of the current level of evidence, large-scale trials should be conducted and attention should be paid to the evaluation of blood pressure variability.

Original title:
Effects of vitamin C supplementation on essential hypertension: A systematic review and meta-analysis by Guan Y, Dai P and Wang H.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7034722/

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Objectives:
Clinical trials examining the cardiovascular protective effects of quercetin in humans have reported conflicting results. Therefore, this review article has been conducted.

Do quercetin supplements reduce plasma lipid levels and blood pressure?

Study design:
This review article included 17 RCTs with a total of 896 participants.

Results and conclusions:
The investigators found pooled results showed that quercetin supplements significantly lowered both systolic blood pressure [WMD = -3.09 mmHg, 95% CI = -4.59 to -1.59, p = 0.0001] and diastolic blood pressure [WMD = -2.86 mmHg, 95% CI = -5.09 to -0.63, p = 0.01].
Neither lipid profiles nor glucose concentrations changed significantly.

The investigators found in subgroup analyses, significant changes in high-density lipoprotein (HDL or good) cholesterol and triglycerides were observed in trials with a parallel design and in which participants consumed quercetin for 8 weeks or more.

The investigators concluded quercetin supplements decrease blood pressure in humans. Moreover, participants who consume quercetin for 8 weeks or more show significantly changed levels of high-density lipoprotein cholesterol (good cholesterol) and triglycerides in trials with a parallel design.  

Original title:
Effect of quercetin supplementation on plasma lipid profiles, blood pressure, and glucose levels: a systematic review and meta-analysis by Huang H, Liao D, [...], Pu R.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31940027

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Objectives:
Is there a causal relationship between psyllium (a dietary fiber) consumption and improvements of risk factors of diabetes?

Study design:
This review article included 9 RCTs with 395 participants.

Results and conclusions:
The investigators found psyllium consumption significantly reduced triglycerides levels with 19.18 mg/dL [WMD = -19.18 mg/dL, 95% CI = -31.76 to -6.60, I2 = 98%].

The investigators found psyllium consumption significantly reduced low-density lipoprotein cholesterol levels with 8.96 mg/dL [WMD = -8.96 mg/dL, 95% CI = -13.39 to -4.52, I2 = 97%].

The investigators found psyllium consumption significantly reduced fasting blood sugar levels with 8.96 mg/dL [WMD = -31.71 mg/dL, 95% CI = -50.04 to -13.38, I2 = 97%].

The investigators found psyllium consumption significantly reduced hemoglobin A1c levels with 0.91% [WMD = -0.91%, 95% CI = -1.31 to -0.51, I2 = 99%].

The investigators found no significant change in high-density lipoprotein, body mass index, cholesterol and weight following psyllium consumption.

The investigators concluded there is a significant reduction in triglycerides, low-density lipoprotein cholesterol (bad cholesterol), fasting blood sugar and hemoglobin A1c levels following psyllium consumption among diabetic patients.

Original title:
The effect of psyllium consumption on weight, body mass index, lipid profile, and glucose metabolism in diabetic patients: A systematic review and dose-response meta-analysis of randomized controlled trials by Xiao Z, Chen H, [...], Wei Y.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31919936

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Psyllium is a form of fiber made from the husks of the Plantago ovata plant’s seeds. The psyllium husk is a naturally occurring source of soluble fiber.
Psyllium is commonly found in cereals, dietary supplements and is also added to some foods including baked products such as breads, cereal bars and rice/grain cakes.
 

Objectives:
Data from in vitro and animal studies support the preventive effect of tea (Camellia sinensis) against colorectal cancer. Further, many epidemiologic studies evaluated the association between tea consumption and colorectal cancer risk, but the results were inconsistent. Therefore, this review article has been conducted.

Does tea consumption reduce colorectal cancer risk?

Study design:
This review article included 20 cohort studies with 2,068,137 participants and 21,437 colorectal cancer cases.

Results and conclusions:
The investigators found that tea consumption had no significant association with colorectal cancer risk for the highest vs. lowest categories [combined RR = 0.97, 95% CI = 0.94-1.01, I2 = 24.0%, p = 0.093] among all studies.

The investigators found stratified analysis showed no significant differences in all subgroups.

The investigators found no significant association between tea consumption and colorectal cancer risk in male [combined RR = 0.97, 95% CI = 0.90-1.04].

The investigators found, however, tea consumption had a marginal significant inverse impact on colorectal cancer risk in female [combined RR = 0.93, 95% CI = 0.86-1.00].

The investigators found a significantly reduced risk of 10% for colorectal cancer for tea consumption among the female studies with no adjustment of coffee intake [RR = 0.90, 95% CI = 0.82-1.00, p  0.05].
However, this reduced risk was not significant among the female studies that adjusted for coffee intake [RR = 0.97, 95% CI = 0.87-1.09, p > 0.05].

The investigators concluded that tea consumption may reduce colorectal cancer risk in female. May reduced because this reduced risk was not significant among the female studies that adjusted for coffee intake.

Original title:
Tea consumption and colorectal cancer risk: a meta-analysis of prospective cohort studies by Zhu MZ, Lu DM, […], Liu ZH.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32078065

Additional information of El Mondo:
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Objectives:
There are differences among the outcomes regarding cognitive impairment in heart failure (HF) because the evidence is fragmented and sample size is small. Therefore, this review article has been conducted.

Does heart failure increase risk of dementia?

Study design:
This review article included 12 studies with 2,406,680 heart failure patients.

Begg test, Egger tests and funnel plots showed no significant risks of publication bias.

Results and conclusions:
The investigators found heart failure significantly increased risk of all-cause dementia with 28% [OR/RR  =  1.28, 95% CI = 1.15 to 1.43, I2 = 70.0%, p    0.001].
Sensitivity analysis showed no changes in the direction of effect when any one study was excluded for the studies on associations between heart failure and all-cause dementia.

The investigators found no significant association between heart failure and risk of Alzheimer's disease [OR/RR  =  1.38, 95% CI = 0.90 to 2.13, I 2 =  74.8%, p =  0.008].
Sensitivity analysis showed no changes in the direction of effect when any one study was excluded for the studies on associations between heart failure and Alzheimer's disease.

The investigators concluded heart failure increases risk of all-cause dementia. In addition, large scale prospective studies are essential to explore the associations between heart failure and risk of Alzheimer's disease.

Original title:
Associations between heart failure and risk of dementia: A PRISMA-compliant meta-analysis by Li J, Wu Y, [...], Nie J.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7004760/

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Objectives:
The benefits of LDL cholesterol-lowering treatment for the prevention of atherosclerotic cardiovascular disease are well established. However, the extent to which these effects differ by baseline LDL cholesterol, atherosclerotic cardiovascular disease risk and the presence of comorbidities remains uncertain. Therefore, this review article has been conducted.

Does LDL cholesterol-lowering treatment reduce risk of major vascular events (a composite of cardiovascular mortality, non-fatal myocardial infarction, non-fatal ischaemic stroke or coronary revascularisation)?

Study design:
This review article included 52 RCTs with a total of 327,037 patients.

Results and conclusions:
The investigators found each 1 mmol/L reduction in LDL cholesterol (bad cholesterol) was associated with a 19% relative risk (RR) reduction for major vascular events [RR = 0.81, 95% CI = 0.78 to 0.84,  p 0.0001].

The investigators found similar reductions (per 1 mmol/L reduction in LDL cholesterol) in trials with participants with LDL cholesterol level of 2.60 mmol/L or lower, 2.61-3.40 mmol/L, 3.41-4.10 mmol/L and more than 4.1 mmol/L [p = 0.232 for interaction] and in a subgroup of patients who all had a baseline LDL cholesterol level less than 2.07 mmol/L [80 mg/dL: RR = 0.83, 95% CI = 0.75-0.92, p = 0.001].

The investigators found greater RR reductions in patients at lower 10-year atherosclerotic cardiovascular disease risk [change in RR per 10% lower 10-year atherosclerotic cardiovascular disease = 0.97, 95% CI = 0.95 to 0.98, p 0.0001] and in patients at younger age across a mean age of 50-75 years [change in RR per 10 years younger age = 0.92, 95% CI = 0.83 to 0.97, p = 0.015].

The investigators found no difference in RR reduction for participants with or without diabetes [p = 0.878 for interaction] and chronic kidney disease [p = 0.934 for interaction].

The investigators concluded for each 1 mmol/L LDL cholesterol lowering, the risk reduction of major vascular events is independent of the starting LDL cholesterol or the presence of diabetes or chronic kidney disease. Patients at lower cardiovascular risk and younger age might have a similar relative reduction in risk with LDL-cholesterol lowering therapies and future studies should investigate the potential benefits of earlier intervention.

Original title:
Intensive LDL cholesterol-lowering treatment beyond current recommendations for the prevention of major vascular events: a systematic review and meta-analysis of randomised trials including 327 037 participants by Wang N, Fulcher J, […], Lal S.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31862150

Additional information of El Mondo:
Find more information/studies on lowering of cholesterol level and cardiovascular disease right here.

Objectives:
Evidence has shown that essential nutrients are highly correlated with the occurrence of esophageal cancer (EC). However, findings from observational studies on the associations between dietary carbohydrate, salt consumption and the risk of esophageal cancer remain controversial. Therefore, this review article has been conducted.

Does carbohydrate or salt consumption (dietary salt intake) increase risk of esophageal cancer?

Study design:
This review article included 11 case-control studies and 1 cohort study, examined carbohydrates consumption and 16 case-control studies and 2 cohort studies, examined salt consumption.

Results and conclusions:
The investigators found dietary carbohydrate intake significantly reduced risk of esophageal cancer with 38% [pooled OR = 0.62, 95% CI = 0.50-0.77].

The investigators found dietary salt intake significantly increased risk of esophageal cancer with 97% [OR = 1.97, 95% CI = 1.50-2.61] in case-control studies.

The investigators found dietary salt intake significantly increased risk of esophageal cancer with 4% [RR = 1.04, 95% CI = 1.00-1.08] in cohort studies.

The investigators concluded dietary salt intake increases risk of esophageal cancer.

Original title:
Associations of dietary carbohydrate and salt consumption with esophageal cancer risk: a systematic review and meta-analysis of observational studies by Banda KJ, Chiu HY, [...], Huang HC.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31995192

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Find more information/studies on carbohydrate, salt and cancer right here.

According to WHO, a high salt intake is a salt intake of more than 5 grams salt per day.

A diet with more than 5 grams salt per day is a diet with mainly products/meals with more than 0.25 grams salt per 100 kcal. Check here which products contain maximum 5 grams salt per 100 kcal.
Use the 7-points nutritional profile app to see whether your daily diet contains maximum 5 grams salt per 100 kcal.

 

Objectives:
Low-carbohydrate diets are associated with cardiovascular risk factors; however, the results of different studies are inconsistent. Therefore, this review article has been conducted.

Do low-carbohydrate diets (diets with less than 40 En% carbohydrates) reduce cardiovascular risk factors?

Study design:
This review article included 12 RCTs with a total of 820 in the observation group (intervention group or low carbohydrate group) and 820 in the control group. The largest sample size was 403 cases and the smallest was 42 cases. The patients’ ages ranged from 31 to 65 years old.
The intervention was a diet with less than 40 En% carbohydrates in the observation group and a diet with 45 En% to 55 En% carbohydrates in the control group.

Results and conclusions:
The investigators found compared with the control group, the triglyceride levels of the low-carbohydrate group (less than 40 En% carbohydrates) significantly decreased by 0.15 mmol/L [95% CI = -0.23 to -0.07, I2 = 75%, p = 0.001].
The results remained unchanged in the sensitivity analysis (after subtracting each of the included studies individually).

The results of the publication bias analysis showed that the funnel plot was not symmetric. The asymmetry of the funnel plot may have been caused by publication bias and other issues.

The investigators found in subgroup analyses, low-carbohydrate diet interventions lasting less than 6 months significantly decreased the triglyceride levels by 0.23 mmol/L [95% CI = -0.32 to -0.15] and those of 12-23 months decreased the levels by 0.17 mmol/L [95% CI = -0.32 to -0.01].

The investigators found compared with the control group, the plasma HDL-cholesterol level (good cholesterol) of the low-carbohydrate group significantly increased by 0.1 mmol/L [95% CI = 0.08 to 0.12, I2 = 41%, p = 0.02].
The results remained unchanged in the sensitivity analysis (after subtracting each of the included studies individually).

The investigators found in subgroup analyses, the increase in plasma HDL-cholesterol levels was 0.08 mmol/L [95% CI = 0.27 to 0.57] for interventions lasting less than 6 months, 0.12 mmol/L [95% CI = 0.09 to 0.15] for those lasting 6-11 months, 0.12 mmol/L [95% CI = 0.08 to 0.15] for those lasting 12-23 months and 0.08 mmol/L [95% CI = 0.04 to 0.12] for those lasting 24 months. 

The investigators found compared with the control group, the serum total cholesterol level of the low-carbohydrate group significantly increased by 0.13 mmol/L [95% CI = 0.08 to 0.19].
The results remained unchanged in the sensitivity analysis (after subtracting each of the included studies individually).

The investigators found compared with the control group, the plasma LDL-cholesterol level (bad cholesterol) of the low-carbohydrate group significantly increased by 0.11 mmol/L [95% CI = 0.02 to 0.19, I2 = 71%, p = 0.0001].
The results remained unchanged in the sensitivity analysis (after subtracting each of the included studies individually).

The investigators found compared with the control group, the body weight of the low-carbohydrate group significantly decreased by 1.58 kg [95% CI = -1.58 to -0.75, I2 = 49%, p = 0.01].
The results remained unchanged in the sensitivity analysis (after subtracting each of the included studies individually).

The investigators found in subgroup analyses, the decrease in body weight was 1.14 kg [95% CI = -1.65 to -0.63] for interventions lasting less than 6 months and 1.73 kg [95% CI = -2.7 to -0.76] for those lasting 6-11 months.

The investigators found compared with the control group, the overall systolic blood pressure of the low-carbohydrate group significantly decreased by 1.41 mmHg [95% CI = -2.26 to -0.56, I2 = 0%, p = 0.84].
The results remained unchanged in the sensitivity analysis (after subtracting each of the included studies individually).

The investigators found in subgroup analyses, the overall systolic blood pressure significantly decreased by 2.97 mmHg [95% CI = -4.62 to -1.31] in the group that received interventions lasting less than 6 months.

The investigators found compared with the control group, the diastolic blood pressure of the low-carbohydrate group significantly decreased by 1.71 mmHg [95% CI = -2.36 to -1.06, I2 = 14%, p = 0.29].
The results remained unchanged in the sensitivity analysis (after subtracting each of the included studies individually).

The investigators found in subgroup analyses, the diastolic blood pressure significantly decreased by 2.76 mmHg [95% CI = -4.07 to -1.46] in the group that received interventions lasting less than 6 months and 2.11 mmHg [95% CI = -3.28 to -0.93] for those lasting 6-11 months.

The investigators concluded low-carbohydrate diets (diets less than 40 En% carbohydrates) have beneficial effects on cardiovascular risk factors at less than 6 months and 6-11 months, but after 2 years of a low-carbohydrate diet, there is no significant effect on cardiovascular risk factors.

Original title:
The effects of low-carbohydrate diets on cardiovascular risk factors: A meta-analysis by Dong T, Guo M, [...], Chen B.

Link:
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0225348

Additional information of El Mondo:
Find more information/studies on carbohydrate consumption and cardiovascular diseases right here.

40 En% carbohydrates means that the total amounts of carbohydrate make up for a 40% of the total kcal of the diet. The easiest way to follow this diet is to choose only meals/products that also contain 40 En% carbohydrates. These products in the supermarket contain 40 En% carbohydrates.

Objectives:
Previous findings on the associations of legume and soy intake with the risk of type 2 diabetes are conflicting. Therefore, this review article (meta-analysis) has been conducted.

Does legume or soy dietary intake reduce risk of type 2 diabetes?

Study design:
This review article included 15 unique cohort studies with a total of 565,810 individuals and 32,093 incident cases (persons with type 2 diabetes).

Overall quality of evidence was rated as moderate for total legumes and low for total soy and soy subtypes.

Results and conclusions:
The investigators found no association between total legumes dietary intake and risk of type 2 diabetes [summary RR = 0.95, 95% CI = 0.79 to 1.14, I2 = 84.8%].
No association because RR of 1 was found in the 95% CI of 0.79 to 1.14. RR of 1 means no risk/association.

The investigators found no association between total soy dietary intake and risk of type 2 diabetes [summary RR = 0.83, 95% CI = 0.68 to 1.01, I2 = 90.8%].

The investigators found no association between soy milk dietary intake and risk of type 2 diabetes [summary RR = 0.89, 95% CI = 0.71 to 1.11, I2 = 91.7%].

The investigators found tofu dietary intake significantly reduced risk of type 2 diabetes with 8% [summary RR = 0.92, 95% CI = 0.84 to 0.99].
Significantly because RR of 1 was not found in the 95% CI of 0.84 to 0.99. RR of 1 means no risk/association.

The investigators found soy protein dietary intake significantly reduced risk of type 2 diabetes with 16% [summary RR = 0.84, 95% CI = 0.75 to 0.95].

The investigators found soy isoflavones dietary intake significantly reduced risk of type 2 diabetes with 12% [summary RR = 0.88, 95% CI = 0.81 to 0.96].

The investigators found in dose-response analysis, significant linear inverse associations for tofu, soy protein and soy isoflavones [all p 0.05].

The investigators concluded dietary intakes of tofu, soy protein and soy isoflavones reduce incident type 2 diabetes. These findings support recommendations to increase intakes of certain soy products for the prevention of type 2 diabetes. However, the overall quality of evidence was low and more high-quality evidence from prospective studies is needed.

Original title:
Legume and soy intake and risk of type 2 diabetes: a systematic review and meta-analysis of prospective cohort studies by Tang J, Wan Y, […], Feng F.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31915830

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Objectives:
The role of zinc in the etiology of type 2 diabetes has been widely reported in recent decades. However, much remains uncertain concerning the effect of zinc on the risk of developing type 2 diabetes. Therefore, this review article has been conducted.

Does zinc reduce risk of type 2 diabetes?

Study design:
This review article included 16 studies.
There was no publication bias.

Results and conclusions:
The investigators found in 7 prospective cohort studies and 1 cross-sectional study (146,027 participants aged between 18 and 84 years and of both genders, belonging to different ethnic groups. Of which, 11,511 type 2 diabetes cases) when comparing the highest versus lowest dietary zinc intakes, a significantly reduced risk of 13% [OR = 0.87, 95% CI = 0.78-0.98, I2 = 64.5%, p = 0.003] for type 2 diabetes.
This relationship was stronger and more evident in rural compared to urban areas [rural areas: OR = 0.59, 95% CI = 0.48-0.73, I2 = 0.0%, p = 0.843 versus urban areas: OR = 0.94, 95% CI = 0.86-1.02, I2 = 43.9%, p = 0.113].

The investigators found no association between supplementary [OR = 0.94, 95% CI = 0.75-1.19, I2 = 85.4%, p = 0.009] or total zinc intake from both diet and supplementation [OR = 0.95, 95% CI = 0.82-1.11, I2 = 56.5%, p = 0.129] and type 2 diabetes risk.

The investigators found in population-based studies that high serum/plasma zinc levels significantly increased risk of type 2 diabetes with 64% [OR = 1.64, 95% CI = 1.25-2.14, I2 > 22.5%, p = 0.275].

The investigators concluded high dietary zinc intake reduces risk of type 2 diabetes. This relationship is stronger and more evident in rural compared to urban areas. However, an elevated serum/plasma zinc concentration is associated with an increased risk of type 2 diabetes in the general population.

Link:
Zinc Intake and Status and Risk of Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis by Fernández-Cao JC, Warthon-Medina M, […], Lowe NM.

Link:
https://www.mdpi.com/2072-6643/11/5/1027/htm

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Serum/plasma zinc levels can be increased by eating products that contain a lot of zinc and/or taking zinc supplements.
 

Objectives:
Does vitamin K reduce risk of cardiovascular disease (CVD) events and mortality?

Study design:
This review article included 21 articles with 222,592 participants.

Results and conclusions:
The investigators found dietary phylloquinone (vitamin K1) intake significantly reduced risk of total cardiovascular disease with 8% [pooled HR = 0.92, 95% CI = 0.84 to 0.99, I2 = 0%, 4 studies].
Significant means that there is an association with a 95% confidence.

The investigators found dietary menaquinone (vitamin K2) intake significantly reduced risk of total cardiovascular disease with 30% [pooled HR = 0.70, 95% CI = 0.53 to 0.93, I2 = 32.1%, 2 studies].
Significant because HR of 1 was not found in the 95% CI of 0.53 to 0.93. HR of 1 means no risk/association.

The investigators found no significant association between dietary vitamin K and all-cause mortality, cardiovascular disease mortality or stroke.

The investigators found elevated plasma desphospho-uncarboxylated MGP (dp-ucMGP), a marker of vitamin K deficiency, was associated with an increased risk of 84% [HR = 1.84, 95% CI = 1.48 to 2.28, I2 = 16.8%, 5 studies] for all-cause mortality.

The investigators found elevated plasma desphospho-uncarboxylated MGP (dp-ucMGP), a marker of vitamin K deficiency, was associated with an increased risk of 96% [HR = 1.96, 95% CI = 1.47 to 2.61, I2 = 0%, 2 studies] for cardiovascular disease mortality.

The investigators found no significant association between circulating total osteocalcin and all-cause mortality or total cardiovascular disease.

The investigators concluded higher dietary vitamin K consumption reduces risk of cardiovascular disease and higher plasma dp-ucMGP concentration, but not total circulating osteocalcin, increases risk of all-cause and cardiovascular disease mortality. However, causal relations cannot be established because of limited number of available studies and larger prospective studies and randomized clinical trials are needed to validate these findings.  

Original title:
Association of vitamin K with cardiovascular events and all-cause mortality: a systematic review and meta-analysis by Chen HG, Sheng LT, […], Pan A.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31119401

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100 grams of fresh parsley provide 548 micrograms (548 mcg) of vitamin K1 or 4.5 days.
 

Objectives:
Does magnesium reduce risk of type 2 diabetes?

Study design:
This review article included 35 cohort studies and 26 RCTs (1,168 participants).

Results and conclusions:
The investigators found compared to the lowest magnesium dietary intake, the highest level was associated with a 22% lower risk for type 2 diabetes.

The investigators found the risk for type 2 diabetes was reduced by 6% for each 100mg increment in daily magnesium dietary intake.

The investigators found in 26 RCTs (1,168 participants) that magnesium supplementation significantly reduced:
-the fasting plasma glucose (FPG) level [SMD = -0.32, 95% CI = -0.59 to -0.05];
-2-h oral glucose tolerance test (2-h OGTT) result [SMD = -0.30, 95% CI = -0.58 to -0.02];
-fasting insulin level [SMD = -0.17, 95% CI = -0.30 to -0.04];
-homeostatic model assessment-insulin resistance (HOMA-IR) score [SMD = -0.41, 95% CI = -0.71 to -0.11];
-triglyceride (TG) level;
-systolic blood pressure (SBP) and;
-diastolic blood pressure (DBP).

The investigators found trial sequential analysis (TSA) showed an inverse association, with most benefits of magnesium supplementation on glucose metabolism being stable.

The investigators concluded magnesium dietary intake has an inverse dose-response association with type 2 diabetes incidence and supplementation appears to be advisable in terms of glucose parameters in type 2 diabetes/high-risk individuals.

Original title:
Association of Magnesium Consumption with Type 2 Diabetes and Glucose Metabolism: a Systematic Literature Review and Pooled Study with Trial Sequential Analysis by Zhao B, Deng H, [...], Zhang W.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31758631

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Objectives:
Observational evidence suggests higher nut consumption is associated with better glycemic control. However, it is unclear if this association is causal. Therefore, this review article has been conducted.

Is there a causal relationship between consumption of tree nuts or peanuts and reduced risk of type 2 diabetes?

Study design:
This review article included a total of 40 RCTs with 2,832 unique participants, with a median duration of 3 months (range: 1-12 months).

Results and conclusions:
The investigators found overall consumption of tree nuts or peanuts had a favourable effect on HOMA-IR values [WMD = -0.23, 95% CI = -0.40 to -0.06, I2 = 51.7%] and fasting insulin levels [WMD = -0.40 μIU/mL, 95% CI = -0.73 to -0.07 μIU/mL, I2 = 49.4%].

The investigators found, however, there was no significant effect of nut consumption on fasting blood glucose levels [WMD = -0.52 mg/dL, 95% CI = -1.43 to 0.38 mg/dL, I2 = 53.4%] or HbA1c [WMD = 0.02%, 95% CI = -0.01% to 0.04%, I2 = 51.0%].

The investigators concluded consumption of peanuts or tree nuts decreases HOMA-IR and fasting insulin levels. These findings suggest that nut consumption may improve insulin sensitivity. In the future, well-designed clinical trials are required to elucidate the mechanisms that account for these observed effects.

Original title:
The effect of nuts on markers of glycemic control: a systematic review and meta-analysis of randomized controlled trials by Tindall AM, Johnston EA, […], Petersen KS.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30722007

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Objectives:
Is there a causal relationship between grape product supplementation and improved lipid profiles in adults?

Study design:
This review article included 48 RCTs.

Results and conclusions:
The investigators found meta-analysis indicated that consumption of grape products significantly reduced the concentration of total cholesterol [MD = -6.196 mg/dL, 95% CI = -9.203 to -3.189], low-density lipoprotein cholesterol (bad cholesterol) [MD = -4.964 mg/dL, 95% CI = -7.594 to -2.334] and triglyceride [MD = -7.641 mg/dL, 95% CI = -12.120 to -3.162].

The investigators found grape product supplementation changed the HDL and LDL in a non-linear fashion based on the dose of polyphenols.

The investigators concluded that grape products have a favorable role in the achievement of a lipid profile target in adults, particularly total cholesterol, low-density lipoprotein cholesterol (bad cholesterol) and triglyceride levels.

Original title:
Effects of grape products on blood lipids: a systematic review and dose-response meta-analysis of randomized controlled trials by Ghaedi E, Moradi S, [...], Mohammadi H.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31517353

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