Nutrition and health

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

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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

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Find more information/studies on tea consumption and cardiovascular disease right here.

Objectives:
Is there a causal relationship between dietary anthocyanins and reduced levels of systemic and vascular inflammation?

Study design:
This review article included 32 RCTs.

Results and conclusions:
The investigators found that dietary anthocyanins significantly decreased levels of C-reactive protein (CRP) [-0.33 mg/L, 95% CI = -0.55 to -0.11, p = 0.00], interleukin-6 (IL-6) [-0.41 ρg/mL, 95% CI = -0.70 to -0.13, p = 0.004], tumor necrosis factor-alpha (TNF-α) [-0.64 ρg/mL, 95% CI = -1.18 to -0.09, p = 0.023], intercellular adhesion molecule-1 [-52.4 ng/mL, 95% CI = -85.7 to -19.1, p = 0.002] and vascular adhesion molecule-1 (VCAM-1)  [-49.6 ng/mL, 95% CI = -72.7 to -26.5, p  0.001]. 

The investigators found that dietary anthocyanins significantly increased adiponectin level [0.75 μg/mL, 95% CI = 0.23 to 1.26, p = 0.004].

The investigators found subgroup analyses showed that administration of higher doses of anthocyanins (>300 mg/day) significantly decreased levels of CRP, IL-6, TNF-α and VCAM-1.

The investigators concluded that >300 mg/day dietary anthocyanins reduce the levels of systemic and vascular inflammation in the subjects.

Original title:
Impact of dietary anthocyanins on systemic and vascular inflammation: Systematic review and meta-analysis on randomised clinical trials by Fallah AA, Sarmast E, […], Jafari T.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31669599

Additional information of El Mondo:
Find here more information/studies about inflammation and anthocyanins.

Inflammation in the body can be measured by the following biomarker; the pro-inflammatory cytokines. The pro-inflammatory cytokines are the C-reactive protein (CRP), IL-1, interleukin-6 (IL-6), IL-8, MCP-1, the vascular adhesion molecule-1 (VCAM-1) and tumor necrosis factor alpha (TNF-α).

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

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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:
Is there a causal relationship between intake of pomegranate and decreased risk of getting inflammation in adults?

Study design:
This review article included 16 randomized controlled trials (RCTs) involving 572 subjects.

Results and conclusions:
The investigators found when compared to placebo, that pomegranate supplementation significantly reduced hs-CRP levels [WMD = -6.57 mg/L, 95% CI = -10.04 to -3.10, p = 0.000].

The investigators found when compared to placebo, that pomegranate supplementation significantly reduced IL-6 levels [WMD = -1.68 pg/mL, 95% CI = -3.52 to -0.157, p = 0.000].

The investigators found when compared to placebo, that pomegranate supplementation significantly reduced TNF-α levels [WMD = -2.37 pg/mL, 95% CI = -3.67 to -1.07, p = 0.00].

The investigators found no association between pomegranate supplementation and CRP levels [WMD = 2.19 mg/dL, 95% CI = -3.28 to 7.67, p = 0.61], E-selectin levels [WMD = 8.42 ng/mL, 95% CI = -22.9 to 39.8, p = 0.599], ICAM levels [WMD = -17.38 ng/mL, 95% CI = -53.43 to 18.66, p = 0.107], VCAM levels [WMD = -69.32 ng/mL, 95% CI = -229.26 to 90.61, p = 0.396] or MDA levels [WMD = 0.031 μmol/L, 95% CI = -1.56 to 0.218, p = 0.746].

The investigators concluded pomegranate supplementation reduces hs-CRP levels, IL-6 levels and TNF-α levels in adults.

Original title:
The effects of pomegranate supplementation on biomarkers of inflammation and endothelial dysfunction: A meta-analysis and systematic review by Wang P, Zhang Q, [...], Yao G.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32147056

Additional information of El Mondo:
Find here more information/studies about fruit and chronic diseases.

Inflammation in humans can be measured by biomarkers, such as highly sensitive C-reactive protein (hs-CRP), interleukin-6 (IL-6) and the tumor necrosis factor alpha (TNF-α).

Inflammation in humans can lower the resistance. A low resistance makes the body susceptible to diseases.
 

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.

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:
Find more information/studies on tea consumption and colorectal cancer right here.

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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Find more information/studies on heart failure and dementia right here.
 

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

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

Objectives:
The activity of hepatitis B virus (HBV) as a risk factor for the incidence and progression of chronic kidney disease (CKD) has not been clarified. Therefore, this review article has been conducted.

Does hepatitis B virus infection increase risk of chronic kidney disease?

Study design:
This review article included 33 studies with a total of 7,849,849 patients.

Results and conclusions:
The investigators found in 11 cohort studies with 1,056,645 patients, that a positive HBV serologic status (hepatitis B virus infection) significantly increased risk of incidence of chronic kidney disease with 40% [adjusted HR = 1.40, 95% CI = 1.16 to 1.69, p 0.001, I2 = 49.5%, p 0.0001].

The investigators found in 10 cross-sectional studies with 3,222,545 patients, no relationship between hepatitis B virus infection and prevalence of chronic kidney disease [adjusted OR = 1.04, 95% CI = 0.90 to 1.218, p = 0.5].

The investigators found meta-regression analysis reported a relationship between positive HBsAg status and incidence of chronic kidney disease in the general population [p 0.015].

The investigators concluded hepatitis B virus infection increases risk of developing of chronic kidney disease in the adult general population. Studies aimed to understand the mechanisms responsible of such association are underway.

Original title:
HBV infection is a risk factor for chronic kidney disease: Systematic review and meta-analysis by Fabrizi F, Cerutti R, […], Messa P.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32037008

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Find here more information/studies about kidney disease.
 

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:
Lead is a known risk factor for amyotrophic lateral sclerosis (ALS). However, the results of studies exploring the relationship between lead exposure and the occurrence of ALS are inconsistent. Therefore, this review article has been conducted.

Does a high lead exposure increase risk of ALS?

Study design:
This review article included 11 case-control studies.

Results and conclusions:
The investigators found a high lead exposure significantly increased risk of ALS with 28% [OR = 1.28, 95% CI = 1.02 to 1.63].
Subgroup and sensitivity analyses showed stable results.

The investigators concluded a high lead exposure increases risk of ALS.

Original title:
Population-based study of environmental/occupational lead exposure and amyotrophic lateral sclerosis: a systematic review and meta-analysis by Meng E, Mao Y, […], Jin W.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31578652

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Find here more information/studies about chronic diseases.
 

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

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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:
Many studies have been reported that dietary meat intake may be associated with the risk of asthma in children, but the results are inconsistent. Therefore, this review article has been conducted.

Does dietary meat intake increase asthma in children?

Study design:
This review article included a total of 9 articles.

No publication bias was detected.

Results and conclusions:
The investigators found dietary meat intake 3 or more times per week compared with never/occasionally intake had no significant association with asthma risk among children [OR = 1.27, 95% CI  =  0.80-2.01, p =  0.308].
Not significant because OR of 1 was found in the 95% CI of 0.80 to 2.01. OR of 1 means no risk/association.

The investigators found, similarly, daily dietary intake of meat did not affect the risk of asthma in children when compared with never/occasionally intake [OR  =  1.13, 95% CI  =  0.93-1.37, p  =  0.234].

The investigators concluded dietary meat intake is not a risk factor for asthma in children. Due to some limitations that exist in this review article, more studies are needed to further assess the association between dietary meat intake and asthma risk in children.

Original title:
Dietary meat intake and risk of asthma in children: evidence from a meta-analysis by Zhang D, Cao L, [...], Wang Z.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31895767

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Find here more information/studies about meat consumption and chronic diseases.
 

Objectives:
The morbidity of eczema has increased in the recent years and the methods to prevent or ameliorate its effects are becoming more important. Therefore, this review article has been conducted.

Do vitamin supplements reduce risk of eczema?

Study design:
This review article included 10 RCTs with a total of 456 patients.
The sample sizes ranged from 5 to 57. The studies were published from 2008 to 2018.
5 studies were conducted on atopic dermatitis, 3 studies were conducted on pediatric atopic dermatitis and 2 studies were conducted on winter-related atopic dermatitis.

Results and conclusions:
The investigators found that the SCORAD index or EASI scores significantly decreased in patients given vitamin D3 (cholecalciferol) supplements [mean difference = -5.96, 95% CI = -7.69 to -4.23, I2 = 33%].

The investigators found that the SCORAD index significantly decreased after the topical application of vitamin B12-containing cream [mean difference = -3.19, 95% CI = -4.27 to -2.10, I2 = 0%]. 

The investigators found that the SCORAD index significantly improved after vitamin E supplementation [mean difference = -5.72, 95% CI = -11.41 to -0.03, I2 = 0%]. 

The investigators concluded vitamin D3, B12 and E supplements could be important therapeutics to help manage eczema patients.

Original title:
Assessment of the Effectiveness of Vitamin Supplement in Treating Eczema: A Systematic Review and Meta-Analysis by Zhu Z, Yang Z, [...], Liu H.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6875217/

Additional information of El Mondo:
Find here more information/studies about vitamin B12, D and E and chronic disease.

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

Additional information of El Mondo:
Find more information/studies on vitamin K, significantly/review article and cardiovascular disease right here.

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

Objectives:
Low-potassium diets are recommended to reduce serum potassium (Sk) and prevent complications of chronic kidney disease (CKD), but evidence underpinning this recommendation has not been systematically reviewed and synthesized. Therefore, this review article has been conducted.

Do patients with chronic kidney disease benefit from low-potassium diets?

Study design:
This review article included 7 studies  with 3,489 participants.

Results and conclusions:
The investigators found in very-low-quality studies that restricted (1,295 mg/d) versus unrestricted (1,570 mg/d) dietary potassium lowered serum potassium by 0.22 mEq/L [95% CI = -0.33 to -0.10, I2 = 0%].

The investigators found in very-low-quality studies that lower (1,725 mg/d) versus higher (4,558 mg/d) dietary potassium was not significantly associated with disease progression [HR = 1.14, 95% CI = 0.77 to 1.70, I2 = 57%].

The investigators found in very-low-quality studies that lower (1,670 mg/d), compared with higher (4,414 mg/d) dietary potassium intake was associated with a 40% reduction in mortality hazard [HR = 0.60, 95% CI = 0.40 to 0.89, I2 = 56%].

The investigators concluded very-low-quality evidence supports consensus that dietary potassium restriction reduces serum potassium in normokalemia and is associated with a reduced risk of death in those with chronic kidney disease. However, high-quality randomized controlled trials are needed to confirm these findings.

Original title:
Effect of Dietary Potassium Restriction on Serum Potassium, Disease Progression, and Mortality in Chronic Kidney Disease: A Systematic Review and Meta-Analysis by Morris A, Krishnan N, […], Lycett D.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31734057

Additional information of El Mondo:
Find here more information/studies about potassium and kidney disease.

Objectives:
Parkinson's disease (PD) is the most common neurodegenerative disease after Alzheimer's dementia. Whereas the exact etiology of Parkinson's disease remains unknown, risk of developing Parkinson's disease seems to be related to a combination of genetic and environmental factors. This also includes abnormal exposure to trace elements of nutritional and toxicological interest. Therefore, this review article has been conducted.

Is there a relationship between exposure to trace elements and Parkinson’s disease risk?

Study design:
This review article included 56 case-control studies reporting data for selenium (cases/controls: 588/721), copper (2,190/2,522), iron (2,956/3,469) and zinc (1,798/1,913) contents in cerebrospinal fluid (CSF) and blood.

Results and conclusions:
The investigators found patients with Parkinson's disease had significantly higher levels of selenium in cerebrospinal fluid compared with controls [+51.6%, WMD = 5.49, 95% CI = 2.82 to 8.15], while levels in serum were similar [-0.2%, WMD = -0.22, 95% CI = -8.05 to 7.62].

The investigators found patients with Parkinson's disease had non-significantly higher levels of copper in cerebrospinal fluid compared with controls [+4.5%, WMD = 1.87, 95% CI = -3.59 to 7.33] and non-significantly lower levels of copper in serum [WMD = -42.79, 95% CI = -134.35 to 48.76].

The investigators found patients with Parkinson's disease had significantly higher levels of iron in cerebrospinal fluid compared with controls [+9.5%, WMD = 9.92, 1.23 to 18.61] and significantly lower levels of iron both in serum/plasma [-5.7%, WMD = -58.19, 95% CI = -106.49 to -9.89] and whole blood [-10.8%, WMD = -95.69, 95% CI = -157.73 to -33.65].

The investigators found patients with Parkinson's disease had significantly lower levels of zinc in cerebrospinal fluid compared with controls [-10.8%, WMD = -7.34, 95% CI = -14.82 to -0.14] and significantly lower levels of zinc in serum/plasma [-7.5%, WMD = -79.93, 95% CI = -143.80 to -16.06].

The investigators found a longer duration of the disease tends to be associated with overall lower trace element levels in either cerebrospinal fluid or blood.

The investigators concluded higher levels of both selenium and iron in cerebrospinal fluid increase Parkinson's disease, while higher levels of zinc in cerebrospinal fluid decrease Parkinson's disease.

Original title:
Selenium and Other Trace Elements in the Etiology of Parkinson's Disease: A Systematic Review and Meta-Analysis of Case-Control Studies by Adani G, Filippini T, […], Vinceti M.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31454800

Additional information of El Mondo:
Find here more information/studies about iron, zinc, selenium and chronic disease
 

Objectives:
Does omega-3 fatty acids supplementation improve serum levels of inflammatory biomarkers (C-reactive protein [CRP], high-sensitivity CRP [hs-CRP], tumor necrosis factor-alpha, interleukin-6) and albumin in patients on hemodialysis?

Study design:
This review article included 8 RCTs comprising 371 patients on hemodialysis.

Results and conclusions:
The investigators found omega-3 supplementation significantly decreased serum levels of CRP in patients on hemodialysis [SMD = -1.95 mg/dL, 95% CI = -3.09 to -0.80] and hs-CRP [SMD = -2.09, 95% CI = -3.62 to -0.56].

The investigators found, however, omega-3 supplementation did not significantly improved albumin [SMD = 0.91, 95% CI = -0.78 to 2.59], tumor necrosis factor-alpha [SMD = -1.51, 95% CI = -3.24 to 0.22] and interleukin-6 levels [SMD = 0.72, 95% CI = -0.56 to 1.99] in patients on hemodialysis.

The investigators concluded omega-3 supplementation leads to a significant decrease in serum levels of CRP and hs-CRP in patients on hemodialysis.

Original title:
The Effect of Omega-3 Supplementation on Serum Levels of Inflammatory Biomarkers and Albumin in Hemodialysis Patients: A Systematic Review and Meta-analysis by Dezfouli M, Moeinzadeh F, [...], Feizi A.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31420233

Additional information of El Mondo:
Find here more information/studies about omega-3 fatty acids and kidney disease.  
 

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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Find more information/studies on fruits, meta-analysis and cholesterol right here.
 

Objectives:
Does green coffee bean extract (GCBE) supplementation reduce blood pressure?

Study design:
This review article included 9 RCTs.

Results and conclusions:
The investigators found a significant reduction in systolic blood pressure (SBP) [WMD = -3.093 mmHg, 95% CI = -3.914 to -2.273, I2 = 0.0%] and diastolic blood pressure (DBP) [WMD = -2.170 mmHg, 95% CI = -2.749 to -1.590, I2 = 46.5%] after green coffee supplementation with low heterogeneity among the studies.

The investigators found in subgroup analysis, a significant reduction in systolic blood pressure and diastolic blood pressure in studies with hypertensive patients, green coffee dosage 400 mg per day and administered for 4 weeks.

The investigators concluded 400 mg coffee bean extract supplementation per day during 4 weeks reduces systolic blood pressure and diastolic blood pressure in hypertensive patients.

Original title:
The effect of green coffee extract supplementation on blood pressure: A systematic review and meta-analysis of randomized controlled trials by Han B, Nazary-Vannani A, […], Kord-Varkaneh H.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31429515

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Find more information/studies on coffee and reducing blood pressure right here.
 

Objectives:
Environmental risk factors regrading rheumatoid arthritis (RA) have not been explored extensively. Selenium (Se), zinc (Zn) and copper (Cu) nutrients were reported to associate with rheumatoid arthritis, but the results were inconsistent. Therefore, this review article has been conducted.

Is there a relationship between serum selenium, zinc and copper levels and rheumatoid arthritis risk?

Study design:
This review article included 41 studies.

Results and conclusions:
The investigators found meta-analysis of 16 studies involving 806 rheumatoid arthritis patients and 959 health controls showed that serum selenium levels [SMD = -1.04, 95% CI = -1.58 to -0.50] were significantly decreased in rheumatoid arthritis patients.

The investigators found meta-analysis of 23 studies involving 1,398 rheumatoid arthritis patients and 1,299 health controls showed that serum zinc levels [SMD = -1.20, 95% CI = -1.74 to -0.67] were significantly decreased in rheumatoid arthritis patients.

The investigators found meta-analysis of 26 studies involving 1,723 rheumatoid arthritis patients and 1,451 health controls showed that serum copper levels [SMD = 1.26, 95% CI = 0.63 to 1.89] were significantly increased in rheumatoid arthritis patients.

The investigators found meta-regression reported that steroid use was positively related to serum level of selenium in rheumatoid arthritis [β = 0.041, 95% CI = 0.002 to 0.079].

The investigators found differences in serum selenium, zinc and copper between rheumatoid arthritis patients and controls were all related with the geographical distribution.

The investigators concluded patients with rheumatoid arthritis have significant decreased serum selenium and zinc levels and increased serum copper levels than health controls, suggesting potential roles of selenium, zinc and copper in the pathogenesis of rheumatoid arthritis. Patients and rheumatologist should give enough attention to the monitor of these elements during follow up.

Original title:
Common trace metals in rheumatoid arthritis: A systematic review and meta-analysis by Ma Y, Zhang X, […], Pan F.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31442958

Additional information of El Mondo:
Find here more information/studies about selenium, zinc and copper and chronic disease.