Nutritional advice

Objectives:
Many studies have investigated the association between dietary iron intake and death due to cardiovascular disease (CVD), but the results were inconsistent. Therefore, this review article has been conducted.

Does dietary iron intake increase risk of death due to cardiovascular disease (cardiovascular disease mortality)?

Study design:
This review article included 19 prospective cohort studies including 720,427 participants (46,045 deaths due to cardiovascular disease).

Results and conclusions:
The investigators found when comparing the highest versus lowest level, the highest level of dietary heme iron intake significantly increased risk of death due to cardiovascular disease with 19% [pooled RR = 1.19, 95% CI = 1.01-1.39].

The investigators found every 1-mg/day increase in dietary heme iron intake significantly increased risk of death due to cardiovascular disease with 25% [pooled RR = 1.25, 95% CI = 1.17-1.33].

The investigators found every 1-mg/day increase in dietary heme iron intake significantly increased risk of death due to stroke with 17% [pooled RR = 1.17, 95% CI = 1.04-1.32].

The investigators found the association between dietary iron intake and cardiovascular disease mortality was linear [p nonlinearity > 0.05].

The investigators concluded higher dietary intake of heme iron (at least 1-mg/day) is associated with a greater risk of cardiovascular disease mortality. Therefore, reducing consumption of heme iron may help to prevent premature death due to cardiovascular disease.

Original title:
Dietary iron intake and risk of death due to cardiovascular diseases: A systematic review and dose-response meta-analysis of prospective cohort studies by Han M, Guan L, […], Lu J.

Link:
https://pubmed.ncbi.nlm.nih.gov/32674239/

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Food items of heme iron are:

• Beef or chicken liver
• Beef
• Canned light tuna
• Canned sardines
• Organ meats
• Oysters, clams, mussels
• Poultry

Objectives:
Previous studies lack consistent conclusions as to whether astaxanthin is actually linked to various health benefits as claimed. Therefore, this review article has been conducted.

Is there a causal relationship between astaxanthin consumption and improvements in risk factors for diabetes or cardiovascular disease?

Study design:
This review article included 14 RCTs.

Results and conclusions:
The investigators found that astaxanthin consumption was not associated with FBS, HbA1c, TC, LDL-C, TG, BMI, BW, DBP and SBP.

The investigators found that astaxanthin consumption was associated with an increase in HDL cholesterol levels [WMD = 1.473 mg/dL, 95% CI = 0.319 to 2.627, p = 0.012].

The investigators found that astaxanthin consumption during ≥12 weeks was associated with a decrease in CRP levels [WMD = -0.528 mg/L, 95% CI = -0.990 to -0.066].

The investigators found that >12 mg/day astaxanthin consumption was associated with a decrease in CRP levels [WMD = -0.389 mg/dL, 95% CI = -0.596 to -0.183].

The investigators concluded that astaxanthin consumption is causally associated with an increase in HDL cholesterol levels (good cholesterol) and a decrease in CRP levels for >12 mg/day astaxanthin consumption during ≥12 weeks. Significant associations are not observed for other outcomes.

Original title:
The effects of astaxanthin supplementation on obesity, blood pressure, CRP, glycemic biomarkers, and lipid profile: A meta-analysis of randomized controlled trials by Xia W, Tang N, [...], Zhu Y.

Link:
https://pubmed.ncbi.nlm.nih.gov/32755613/

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Find here more information/studies about astaxanthin consumption and cholestrerol.

Objectives:
Is there a causal relationship between dairy products or calcium supplements and the reduction in fat mass and BMI among overweight or obese adults?

Study design:
This review article included 10 and 14 RCTs with ≥ 12 weeks interventions of calcium supplements and dairy products among overweight (BMI>25) or obese (BMI>30) adults aged ≥18.

Results and conclusions:
The investigators found that dairy products significantly reduced fat mass among overweight or obese adults [SMD = -0.40, 95% CI = -0.77 to -0.02].
This reduction was also significant in the analysis of RCTs with low risk of bias scores.

The investigators found that dairy products significantly reduced BMI among overweight or obese adults [SMD = -0.46 kg/m², 95% CI = -0.67 to -0.26].
This reduction was also significant in the analysis of RCTs with low risk of bias scores.

The investigators found that calcium supplements significantly reduced fat mass among overweight or obese adults [SMD = -0.15, 95% CI = -0.28 to -0.02].
However, this reduction was not significant in the analysis of RCTs with low risk of bias scores.

The investigators concluded there is a causal relationship between dairy products without distinction of fat percentage and the reduction in fat mass and BMI among overweight or obese adults.

Original title:
Meta-analysis of randomized controlled trials on calcium supplements and dairy products for changes in body weight and obesity indices by Hong JY, Lee JS, [...], Kim MK.

Link:
https://pubmed.ncbi.nlm.nih.gov/33292017/

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Objectives:
Dyslipidemia is a common metabolic disease worldwide and also an important predisposing factor for cardiovascular diseases (CVDs). Coffee is loved by people all over the world; however, the association between coffee consumption and blood lipids has yielded inconsistent results. Therefore, this review article has been conducted.

Is there a causal relationship between coffee consumption and dyslipidemia?

Study design:
This review article included 12 RCTs.

Results and conclusions:
The investigators found pooled results showed that coffee consumption significantly increased total cholesterol (TC) levels [WMD = 0.21 mmol/L, 95% CI = 0.04 to 0.39, p = 0.017].  
Significant means that there is an association with a 95% confidence.

The investigators found pooled results showed that coffee consumption significantly increased triglyceride (TG) levels [WMD = 0.12 mmol/L, 95% CI = 0.03 to 0.20, p = 0.006].  
Significant because the calculated p-value of 0.006 was less than the p-value of 0.05.

The investigators found pooled results showed that coffee consumption significantly increased LDL cholesterol (bad cholesterol) levels [WMD = 0.14 mmol/L, 95% CI = 0.05 to 0.24, p = 0.003].  

The investigators found pooled results showed that coffee consumption had no significant effect on HDL cholesterol (good cholesterol) levels [WMD = -0.01 mmol/L, 95% CI = -0.06 to 0.04, p = 0.707].
No significant means that there is no association with a 95% confidence.

The investigators found dose-response analysis results revealed significant positive nonlinear associations between coffee consumption and the increase in total cholesterol, LDL cholesterol and triglyceride levels.

The investigators concluded that coffee consumption is associated with an elevated risk for dyslipidemia and cardiovascular diseases. So a reasonable habit of coffee consumption (3 cups/d) is essential for the prevention of dyslipidemia.  

Original title:
Effect of coffee consumption on dyslipidemia: A meta-analysis of randomized controlled trials by Du Y, Lv Y, […], Luo Q.

Link:
https://pubmed.ncbi.nlm.nih.gov/33239163/

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Dyslipidemia is elevation of plasma cholesterol, triglycerides (TGs), or both, or a low HDL cholesterol (good cholesterol) level that contributes to the development of atherosclerosis. Atherosclerosis is the main underlying cause of cardiovascular disease (CVD).

Objectives:
Does pistachio supplementation reduce obesity risk?

Study design:
This review article included 11 randomized controlled trials (RCTs) with 1,593 subjects.

The assigned pistachio intake was below 50 g/d in 3 studies.
Intervention times were shorter than 12 weeks in 4 studies.
There was no significant publication bias.

Results and conclusions:
The investigators found compared to the control diet group, the pistachio supplementation regimen significantly decreased BMI [-0.18 kg/m², 95% CI = -0.26 to -0.11 kg/m², p 0.001, I2 = 29.8%, p = 0.180].

The investigators found compared to the control diet group, the pistachio supplementation regimen did not significantly change waist circumference [net change = 0.76 cm, 95% CI = -0.11 to 1.63 cm, p = 0.087, I2 = 7.0%, p = 0.340].

The investigators found compared to the control diet group, the pistachio supplementation regimen had no effect on body weight [net change = 0.22 kg, 95% CI = -0.50 to 0.07 kg, p = 0.141, I2 = 0.0%, p = 0.962].

The investigators concluded compared to a controlled dietary intake, an adequate amount of pistachio supplementation lowers BMI without increasing body weight, which supports the view that pistachio consumption is beneficial for human health.

Original title:
The relationship between pistachio (Pistacia vera L) intake and adiposity: A systematic review and meta-analysis of randomized controlled trials by Xia K, Yang T, […], Chen XZ.

Link:
https://journals.lww.com/md-journal/Fulltext/2020/08210/The_relationship_between_pistachio__Pistacia_vera.7.aspx

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Objectives:
Dietary sodium intake has received considerable attention as a potential risk factor of cardiovascular disease. However, evidence on the dose-response association between dietary sodium intake and cardiovascular disease risk is unclear. Therefore, this review article has been conducted.

Is there a dose-response association between dietary sodium intake and cardiovascular disease (CVD) risk?

Study design:
This review article included 36 cohort studies with a total of 616,905 participants.
The duration of follow-up ranged from 2.7 years to 29 years.

For dietary sodium intake assessment, 18 of the studies were based on twenty-four urinary excretion, 7 used food frequency questionnaires, 8 used 24 h dietary recall, 2 used dietary records; 1 used a self-administered questionnaire and 1 used single spot urine sodium excretion.
The daily dietary sodium intake ranged from 1.0 to 7.5 g.

The mean score (± standard deviation) for the quality of the included studies was 8.0 ± 1.0 according to the Newcastle-Ottawa Scale.

Results and conclusions:
The investigators found compared with individuals with low sodium intake, individuals with high sodium intake had an 19%-higher adjusted risk of cardiovascular disease [rate ratio = 1.19, 95% CI = 1.08 to 1.30].

The investigators found in dose-response meta-analysis that the risk of cardiovascular disease significantly increased by 6% when 1 g dose of sodium was ingested [rate ratio = 1.06, 95% CI = 1.01 to 1.11].

The investigators concluded that high sodium intake is an important risk factor of cardiovascular disease (CVD) and in dose-response meta-analysis, every 1 g of dietary sodium intake increases the risk of cardiovascular disease by 6%.

Original title:
Dietary Sodium Intake and Risk of Cardiovascular Disease: A Systematic Review and Dose-Response Meta-Analysis by Wang YJ, Yeh TL, [...], Chien KL.

Link:
https://www.mdpi.com/2072-6643/12/10/2934/htm

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1 gram salt (sodium chloride) = 0.4 gram sodium.

Objectives:
Epidemiological studies on the impact of fish consumption on coronary heart disease (CHD) incidence have shown inconsistent results. Therefore, this review article has been conducted.

Does dietary intake of fish reduce coronary heart disease incidence and mortality?

Study design:
This review article included 40 prospective cohort studies (22 studies investigated the association between fish consumption and coronary heart disease incidence (28,261 persons with coronary heart disease and 918,783 participants) and 27 studies investigated the association between fish consumption and coronary heart disease mortality (10,568 events and 1,139,553 participants)).

No evidence of publication bias was found.

Results and conclusions:
The investigators found higher fish consumption was significantly associated with a 9%-lower coronary heart disease risk [RR = 0.91, 95% CI = 0.84 to 0.97, I2 = 47.4%].

The investigators found a significant correlation between fish consumption and coronary heart disease risk in the female subgroup [RR = 0.85, 95% CI = 0.78 to 0.92, I2 = 5.6%], the subgroup with a follow-up period of ≥10 years [RR = 0.91, 95% CI = 0.84 to 0.99, I2 = 51.5%] and the subgroup with an article quality of ≥7 points [RR = 0.90, 95% CI = 0.83 to 0.98, I2 = 50.6%].
However, it was not found in the male subgroup, the subgroup with a follow-up period of 10 years and the subgroup with an article quality of 7 points.

The investigators found higher fish intake was significantly associated with a 15%-lower coronary heart disease mortality risk [RR = 0.85, 95% CI = 0.77 to 0.94, I2 = 51.3%].

The investigators found the summary results did not change significantly in sensitivity analysis.

The investigators found dose-response analysis showed that the coronary heart disease incidence and mortality were reduced by 4%, respectively, with a 20 g/day increment in fish consumption.

The investigators concluded that a higher dietary intake of fish reduces coronary heart disease incidence and mortality. This finding has important public health implications in terms of the prevention of coronary heart disease. Since most of the research was conducted in male groups and Western countries, further research needs to be performed in female groups and other regions.

Original title:
Fish Consumption and Coronary Heart Disease: A Meta-Analysis by Zhang B, Xiong K, […], Ma A.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7468748

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In practice, higher fish consumption means at least twice a week of fish consumption (150 grams of fish at a time).

Objectives:
There are numerous trials reported the effect of alpha-lipoic acid (ALA) on obesity measurements; while no summarised dose-response meta-analysis is available to address the effects of dose and duration of ALA supplementation on obesity measurements. Therefore, this review article has been conducted.

Does alpha-lipoic acid supplementation improve obesity measurements including weight, body mass index (BMI), waist circumference (WC), waist to hip ratio (WHR) and fat mass (FM)?

Study design:
This review article included 18, 21 and 8 RCTs of ALA-weight, ALA-BMI, ALA-WC, respectively.

Results and conclusions:
The investigators found in two-class meta-analysis, alpha-lipoic acid supplementation significantly reduced weight [WMD = -2.29 kg, 95% CI = -2.98 to -1.60, p 0.01] and BMI [WMD = -0.49 g/m², 95% CI = -0.83 to -0.15, p = 0.005] but had no effect on waist circumference [WMD = -2.57 cm, 95% CI = -8.91 to 3.76, p = 0.426].

The investigators found while the dose-response meta-analysis revealed that the duration of alpha-lipoic acid supplementation was a significant factor affecting waist circumference reduction [p non-linearity = 0.047].
While no evidence of departure from linearity was observed for other variables; moreover, subgrouping also revealed that gender could be an important factor affecting the alpha-lipoic acid impact on waist circumference, which was significant among women [WMD = -4.099, 95%CI = -7.837 to -0.361, p = 0.032].

The investigators concluded that alpha-lipoic acid supplementation reduces BMI, weight in a two-class meta-analysis without evidence of departure from linearity in terms of dose or duration. While the association of alpha-lipoic acid supplementation on waist circumference is dependent to the duration of the study. Although further trials evaluating the other obesity measurements specially central obesity will be helpful to infer a more reliable result.

Original title:
Alpha-lipoic acid supplementation significantly reduces the risk of obesity in an updated systematic review and dose response meta-analysis of randomised placebo-controlled clinical trials by Vajdi M and Farhangi MA.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32091656

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Objectives:
Observational studies regarding the putative associations between dietary intake of homocysteine metabolism-related B-vitamins (vitamin B6, folate and vitamin B12) and stroke risk have yielded inconsistent results. Therefore, this review article has been conducted.

Does dietary intake of vitamin B6, folate or vitamin B12 reduce stroke risk?

Study design:
This review article included 1 nested case-control study and 11 prospective cohort studies comprising 389,938 participants and 10,749 cases (persons with stroke).

The studies were published from 2002 through to 2019 and the follow-up period ranged from 4.2 to 19 years.

All 12 studies provided risk estimates adjusted for cigarette smoking and most studies also adjusted for other conventional risk factors, including BMI, energy intake, alcohol consumption, hypertension and/or physical activity.

Study quality scores ranged from 5 to 9; the mean quality score was 7.4.

There was no evidence of publication bias.

Results and conclusions:
The investigators found for the highest versus the lowest category of dietary vitamin B6 intake, a significantly reduced risk of 16% for stroke [RR = 0.84, 95% CI = 0.73 to 0.97, I2 = 48.8%].

The investigators found in dose-response analysis that each 0.5 mg/d increment in vitamin B6 dietary intake was associated with a 6% reduction in the risk of stroke [RR = 0.94, 95% CI = 0.89 to 0.99, I2 = 77.0%].

The investigators found for the highest versus the lowest category of dietary folate intake, a significantly reduced risk of 15% for stroke [RR = 0.85, 95% CI = 0.78 to 0.94, I2 = 11.5%].

The investigators found in dose-response analysis that each 100 μg/d increase in dietary folate intake was associated with a 6% reduction in the risk of stroke [RR = 0.94, 95% CI = 0.90 to 0.98, I2 = 46.8%].

The investigators found, in contrast, no significant association between dietary vitamin B12 intake and the risk of stroke, with an RR of 1.01 [95% CI = 0.97 to 1.06] per 3 μg/d increase.

The investigators concluded increased dietary intake of vitamin B6 (at least 0.5 mg/d) and dietary folate intake (at least 100 μg/d) is associated with a reduced risk of stroke, supporting the notion that increasing habitual folate and vitamin B6 intake may provide a small but beneficial effect with respect to stroke.

Original title:
Dietary Intake of Homocysteine Metabolism-Related B-Vitamins and the Risk of Stroke: A Dose-Response Meta-Analysis of Prospective Studies by Chen L, Li Q, [...], Wang F.

Link:
https://academic.oup.com/advances/advance-article/doi/10.1093/advances/nmaa061/5854025

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Objectives:
Hypertension is regarded as a major and independent risk factor of cardiovascular diseases and numerous studies observed an inverse correlation between vitamin C intake and blood pressure. Therefore, this review article has been conducted.

Does a high serum vitamin C reduce blood pressure?

Study design:
This review article included 11 cross-sectional studies and 7 case-control studies. These studies comprised 22,200 observational subjects and were conducted from the year 1990 to 2017. Of the 18 articles, 14 were published in the English language and 4 were in Chinese.

Assessed with NOS, all the case-control studies yield a high quality averaging with 7.143 scores. And the result of AHRQ indicates a moderate quality with all cross-sectional studies scoring between 4 and 7.

Results and conclusions:
The investigators found random-effects model showed serum level of vitamin C of hypertensive subjects was 15.13 μmol/L lower than the normotensives [MD = -15.13, 95% CI = -24.19 to -6.06, p = 0.001, I2 = 98%].

The investigators found subgroup analysis showed that hypertensive subjects who took antihypertensive drugs had a 15.97 μmol/L lower serum vitamin C compared with normotensive ones.

The investigators found serum vitamin C had a significant inverse relation with both systolic blood pressure [Fisher′s Z = -0.17, 95% CI = -0.20 to -0.15, p 0.00001] and diastolic blood pressure [Fisher′s Z = -0.15, 95% CI = -0.20 to -0.10, p 0.00001].

The investigators concluded people with hypertension have a relatively low serum vitamin C and vitamin C is inversely associated with both systolic blood pressure and diastolic blood pressure.

Original title:
Association between Serum Vitamin C and the Blood Pressure: A Systematic Review and Meta-Analysis of Observational Studies by Ran L, Zhao W, […], Bu H.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7211237/

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Objectives:
Is there a causal relationship between black or green tea consumption and lowering blood pressure in subjects with elevated blood pressure (BP) or hypertension?
 
Study design:
This review article included 5 RCTs with 408 individuals.

None of the studies reported any side effects.

Results and conclusions:
The investigators found regular tea consumption significantly reduced systolic blood pressure [WMD = -4.81 mmHg, 95% CI = -8.40 to -1.58, p = 0.004] in subjects with elevated blood pressure (BP) or hypertension.

The investigators found regular tea consumption significantly reduced diastolic blood pressure [WMD = -1.98 mmHg, 95% CI = -3.77 to -0.20, p = 0.029] in subjects with elevated blood pressure (BP) or hypertension.

The investigators found, however, excluding the most heterogeneous trials showed that regular tea intake significantly reduced systolic blood pressure and diastolic blood pressure by about -3.53 and -0.99 mmHg, respectively.

The investigators found based on meta-regression findings, the longer the duration of tea intake (≥3 months), the higher the decrease in both systolic blood pressure and diastolic blood pressure.

The investigators found categorized studies, according to the tea type, revealed that the hypotensive effects of green tea were more pronounced compared to black tea.

The investigators concluded regular tea consumption, particularly green tea during ≥3 months reduces systolic blood pressure and diastolic blood pressure in subjects with elevated blood pressure (BP) or hypertension. Hence, it may be applicable to physicians, health care providers and particularly hypertension patients.

Original title:
The Effects of Regular Consumption of Green or Black Tea Beverage on Blood Pressure in Those With Elevated Blood Pressure or Hypertension: A Systematic Review and Meta-Analysis by Mahdavi-Roshan M, Salari A, […], Ashouri A.

Link:
https://www.sciencedirect.com/science/article/abs/pii/S0965229919316899?via%3Dihub

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Objectives:
Epidemiologic studies, including trials, suggest an association between potassium intake and blood pressure (BP). However, the strength and shape of this relationship is uncertain. Therefore, this review article has been conducted.

What is the strength and shape of the relationship between potassium intake and blood pressure (BP)?
 
Study design:
This review article included 32 RCTs with a duration ≥4 weeks using the recently developed 1‐stage cubic spline regression model. This model allows use of trials with at least 2 exposure categories.
Most trials were conducted in adults with hypertension using a crossover design and potassium supplementation doses that ranged from 30 to 140 mmol (1173 and 5474 mg) per day.

Results and conclusions:
The investigators found a U‐shaped relationship between 24‐hour active and control arm differences in potassium excretion and blood pressure (BP) levels, with weakening of the blood pressure reduction effect above differences of 30 mmol/d and a blood pressure increase above differences ≈80 mmol/d.

The investigators found achieved potassium excretion analysis also identified a U‐shaped relationship. The blood pressure lowering effects of potassium supplementation were stronger in participants with hypertension and at higher levels of sodium intake.

The investigators found blood pressure increased with high potassium excretion in participants with antihypertensive drug‐treated hypertension but not in their untreated counterparts.

The investigators concluded that an adequate intake of potassium (≤30 mmol (1173 mg) per day) is desirable to achieve a lower blood pressure level but excessive potassium supplementation (>80 mmol (3128 mg) per day) should be avoided, particularly in specific subgroups.

Original title:
Potassium Intake and Blood Pressure: A Dose‐Response Meta‐Analysis of Randomized Controlled Trials by Filippini T, Naska A, […], Whelton PK.

Link:
https://www.ahajournals.org/doi/full/10.1161/JAHA.119.015719?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub++0pubmed&

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Objectives:
Does coenzyme Q10 supplementation reduce body weight and body mass index (BMI) of patients in randomized controlled clinical trial studies (RCTs)?

Study design:
This review article included 17 RCTs.

Results and conclusions:
The investigators found results of random-effect size meta-analysis showed that supplementation with coenzyme Q10 had no significant decreasing effects on body weight [WMD = 0.28 kg, 95% CI = -0.91 to 1.47, p = 0.64] and BMI [WMD = -0.03, 95% CI = -0.4 to 0.34, p = 0.86] of study participants.
No significant because the calculated p-value of 0.64 was larger than the p-value of 0.05.
Subgroup analysis revealed that dosage of Q10 and trial duration could not differ the results of Q10 supplementation.

The investigators concluded that coenzyme Q10 supplementation has no decreasing effects on body weight and BMI.

Original title:
Effect of Q10 supplementation on body weight and body mass index: A systematic review and meta-analysis of randomized controlled clinical trials by Saboori S, Rad EY, […], Falahi E.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31336462

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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/

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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/

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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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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

Additional information of El Mondo:
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

Additional information of El Mondo:
Find more information/studies on fruit consumption and lowering of cholesterol levels 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

Additional information of El Mondo:
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:
Results regarding the association between fish intake and risk of metabolic syndrome (MetS) are ambiguous. Therefore, this review article has been conducted.

Does fish consumption reduce risk of metabolic syndrome?

Study design:
This review article included 10 cross-sectional studies and 6 cohort studies.

Results and conclusions:
The investigators found fish consumption significantly reduced risk of metabolic syndrome with 20% [OR = 0.80, 95% CI = 0.66 to 0.96, p = 0.017, I2 = 62.9%] in cohort studies.
However, this reduced risk was not significant in cross-sectional studies [OR = 0.80, 95% CI = 0.70 to 1.02, p = 0.085, I2 = 50.1%].
Significantly because OR of 1 was not found in the 95% CI of 0.6 to 0.96. OR of 1 means no risk/association.

The investigators found a significant non-linear association between fish intake levels and risk of metabolic syndrome [p for non-linearity = 0.010].

The investigators concluded that fish consumption reduces risk of metabolic syndrome when combining data from prospective cohort studies. Further studies are needed to confirm such an effect.

Original title:
A systematic review and meta-analysis of the association between fish consumption and risk of metabolic syndrome by Karimi G, Heidari Z, [...], Haghighatdoost F.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32127332

Additional information of El Mondo:
Find more information/studies on fish consumption and obesity/overweight 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:
Find here more information/studies about flaxseed and heart disease.

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/

Additional information of El Mondo:
Find more information/studies on lowering of blood pressure, vitamin C and cardiovascular disease right here.

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

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