Nutritional advice

Objectives:
Several previous meta-analyses show a consistent inverse association between nut consumption and all-cause mortality, but the associations with cause-specific mortality remain uncertain. Therefore, this meta-analysis (review article) has been conducted.

Does nut consumption reduce all-cause and cause-specific mortality?

Study design:
This review article included 18 prospective cohort studies with 81,034 deaths.

Results and conclusions:
The investigators found random-effects meta-analysis of 18 studies with 81,034 deaths showed a significant reduced risk of 19% [summary RR = 0.81, 95% CI = 0.78-0.84] for all-cause mortality for high compared with low nut consumption. This significant reduced risk was broadly consistent within subgroups according to various study and population characteristics and within sensitivity analyses that took into account potential confounders.

The investigators found random-effects meta-analysis of 17 studies with 20,381 deaths showed a significant reduced risk of 25% [summary RR = 0.75, 95% CI = 0.71-0.79] for cardiovascular mortality for high compared with low nut consumption. This significant reduced risk was broadly consistent within subgroups according to various study and population characteristics and within sensitivity analyses that took into account potential confounders.

The investigators found random-effects meta-analysis of 14 studies with 10,438 deaths showed a significant reduced risk of 27% [summary RR = 0.73, 95% CI = 0.67-0.80] for coronary heart disease mortality for high compared with low nut consumption. This significant reduced risk was broadly consistent within subgroups according to various study and population characteristics and within sensitivity analyses that took into account potential confounders.

The investigators found random-effects meta-analysis of 13 studies with 4,850 deaths showed a significant reduced risk of 18% [summary RR = 0.82, 95% CI = 0.73-0.91] for stroke mortality for high compared with low nut consumption. This significant reduced risk was broadly consistent within subgroups according to various study and population characteristics and within sensitivity analyses that took into account potential confounders.

The investigators found random-effects meta-analysis of 11 studies with 21,353 deaths showed a significant reduced risk of 13% [summary RR = 0.87, 95% CI = 0.80-0.93] for cancer mortality for high compared with low nut consumption. This significant reduced risk was broadly consistent within subgroups according to various study and population characteristics and within sensitivity analyses that took into account potential confounders.

The investigators found peanut (5 studies) and tree nut (3 studies) consumption were similarly associated with mortality risks.

The investigators found dose-response analyses suggested evidence for nonlinear associations between nut consumption and mortality [p-nonlinearity 0.001 for all outcomes except cancer mortality], with mortality risk levelling off at the consumption of about 3 servings per week (12g/day).

The investigators concluded that nut consumption is associated with reduced all-cause and cause-specific mortality, with the strongest reduction for coronary heart disease (CHD) mortality. Both tree nuts and peanuts lower mortality and most of the survival benefits could be achieved at a relative low level of nut consumption (up to 12g/day).

Original title:
Nut consumption in relation to all-cause and cause-specific mortality: a meta-analysis 18 prospective studies by Chen GC, Zhang R, [...], Qin LQ.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28875220

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Objectives:
Anthocyanins are of interest due to their anti-oxidative and vasodilatory properties. Earlier reviews have shown that berries and other anthocyanin rich foods or extracts can improve vascular health. However, the effect of anthocyanins on vascular function has not yet been reviewed. Therefore, this review article (meta-analysis) has been conducted.

Does anthocyanin supplementation improve vascular function?

Study design:
This review article included 29 RCTs (15 were parallel and 14 were crossover designs).
Anthocyanin intakes ranged from 1 to 724 mg/day.
Most studies (n = 19) involved participants in the middle to older age group (mean age ≥ 40 years).
The number of participants that completed each study ranged from 10 to 146.
Intervention durations ranged from 1 h to 6 h in the acute studies and one week to six months in the chronic studies.

There was no publication bias.

Results and conclusions:
The investigators found compared to placebo-control, acute anthocyanin supplementation (1-8 h post consumption of anthocyanin doses between 7 and 724 mg) significantly improved FMD [SMD = 3.92%, 95% CI = 1.47 to 6.38, p = 0.002, I2 = 91.8%].
No improvements were observed in PAT-RHI [SMD = 0.08, 95% CI = -0.34 to 0.50, p = 0.71, I2 = 0%].
Collectively, (i.e., the pooling of studies using FMD and/or PAT-RHI) anthocyanins may improve vascular reactivity [overall SMD = 2.41, 95% CI = 0.91 to 3.91, p = 0.002, I2 = 92.6%].

The investigators found compared to placebo-control, acute anthocyanin supplementation (1-8 h post consumption of anthocyanin doses between 7 and 724 mg) also significantly improved arterial stiffness, using PWV [SMD = -1.27 m/s, 95% CI = -1.96 to -0.58, p = 0.000, I2 = 17.9%].

The investigators found pulse wave velocity was improved following acute anthocyanin supplementation only [SMD = -1.27 m/s, 95% CI = -1.96 to -0.58, p = 0.000, I2 = 17.8%]. 

The investigators found compared to placebo-control, chronic anthocyanin supplementation (one week to six months and used anthocyanin doses of 12 to 320 mg/day) significantly improved FMD [SMD = 0.84%, 95% CI = 0.55 to 1.12, p = 0.000, I2 = 62.5%].
Collectively (i.e., the pooling of studies using FMD and/or PAT-RHI), chronic anthocyanin supplementation may improve vascular reactivity [overall SMD = 0.77, 95% CI = 0.37 to 1.16, p = 0.000, I2 = 85.3%].

The investigators concluded that both acute and chronic anthocyanin supplementation improve vascular health, particularly with respect to vascular reactivity measured by FMD. However, more research is required to determine the optimal dosage and the long-term effects of anthocyanin consumption.

Original title:
The Effect of Anthocyanin-Rich Foods or Extracts on Vascular Function in Adults: A Systematic Review and Meta-Analysis of Randomised Controlled Trials by Fairlie-Jones L, Davison K, […], Hill AM.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5579701/

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Objectives:
Whether iron is associated with the development of gestational diabetes mellitus (GDM) is not clear. Therefore, this review article (meta-analysis) has been conducted.

Do increased dietary intake of iron and body iron status increase risk of gestational diabetes mellitus in pregnant women? 

Study design:
This review article included 12 case-control  studies, 9 cohort studies and  2  randomized  controlled  studies (RCT) with in total, 3,034 gestational diabetes mellitus pregnant women and 26,344 non-gestational diabetes mellitus pregnant women.

Results and conclusions:
The investigators found high dietary intake of heme iron was significantly associated with a 65% gestational diabetes mellitus risk [RR = 1.65, 95% CI = 1.28 to 2.12, I2 = 0%].

The investigators found for each 1 mg/day increment of dietary heme iron intake a significantly 38% gestational diabetes mellitus risk [RR = 1.38, 95% CI = 1.19 to 1.61, I2 = 0%].

The investigators found higher body iron stores, as represented by serum ferritin level, were correlated with a significantly increased gestational diabetes mellitus risk of 64% [RR = 1.64, 95% CI = 1.27 to 2.11, I2% = 7%].

The investigators found no association between gestational diabetes mellitus and the intakes of nonheme iron, total iron or supplemental iron.

The investigators concluded increased dietary intake of heme iron (at least 1 mg/day) and body iron status are positively associated with the risk of gestational diabetes mellitus development in pregnant women. Future studies are warranted to better understand the role of iron in gestational diabetes mellitus development.

Original title:
Dietary intake of heme iron and body iron status are associated with the risk of gestational diabetes mellitus: a systematic review and meta-analysis by Zhao L, Lian J, [...], Wang F.

Link:
http://apjcn.nhri.org.tw/server/APJCN/26/6/1092.pdf

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Gestational diabetes mellitus is a condition in which a woman without diabetes develops high blood sugar levels during pregnancy. Gestational diabetes mellitus affects between 2% and 5% of pregnant women.

Objectives:
Although epidemiological studies have examined the role of chocolate in preventing cardiometabolic disease, the results remain inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Does chocolate consumption reduce risk of coronary heart disease (CHD), stroke and diabetes?

Study design:
This review article included 14 prospective cohort studies, with 508,705 participants from six countries and 7,267 coronary heart disease (CHD) cases, 8,197 stroke cases and 13,271 diabetes cases.
The follow-up duration of the studies ranged from 5 to 16 years.
One serving was defined as 30g of chocolate.
The majority of chocolate consumed in the included studies was milk or dark chocolate.

Results and conclusions:
The investigators found in 6 cohort studies for the highest versus lowest intake of chocolate a significant reduced risk of 10% for coronary heart disease [pooled RR = 0.90, 95% CI = 0.82-0.97, I2 = 24.3%, p = 0.25]. Leave-one-out sensitivity analysis had no significant influence on the pooled results.

The investigators found regarding CHD subtype, a significant reduced risk of 14% [RR = 0.86, 95% CI = 0.77-0.96] for myocardial infarction.

The investigators found for studies with follow-up duration of 10 years a significant reduced risk of 28% for coronary heart disease [RR = 0.72, 95% CI = 0.57-0.92].

The investigators found for studies with follow-up duration of ≥10 years a significant reduced risk of 8% for coronary heart disease [RR = 0.92, 95% CI = 0.86-0.99].

The investigators found in dose-response meta-analysis of 5 studies a curvilinear association between chocolate consumption and risk of coronary heart disease [p for nonlinearity = 0.006].

The investigators found in dose-response meta-analysis, compared with no intake, a significant reduced risk of 6% for coronary heart disease for 1 serving (30g) chocolate per week [RR = 0.94, 95 CI = 0.90-0.99].   

The investigators found in dose-response meta-analysis, compared with no intake, a significant reduced risk of 9% for coronary heart disease for 3 servings (90g) chocolate per week [RR = 0.91, 95 CI = 0.85-0.97].   

The investigators found in dose-response meta-analysis, compared with no intake, a significant reduced risk of 11% for coronary heart disease for 7 servings (210g) chocolate per week [RR = 0.89, 95 CI = 0.83-0.95].   

The investigators found in dose-response meta-analysis, compared with no intake, a significant reduced risk of 12% for coronary heart disease for 10 servings (300g) chocolate per week [RR = 0.88, 95 CI = 0.81-0.95].   

The investigators found in 8 reports from 7 studies for the highest versus lowest level of chocolate consumption a significant reduced risk of 16% for stroke [pooled RR = 0.84, 95% CI = 0.78-0.90, I2 = 0%, p = 0.49]. The pooled risk of total stroke was not obviously modified in the sensitivity analysis by excluding one study at a time
Egger’s test suggested the presence of publication bias [p = 0.008]. However, after introducing the “trim and fill” method to adjust this bias, the overall risk estimate remained significant in favor of chocolate intake [RR = 0.86, 95% CI = 0.79-0.92].

The investigators found with regard to stroke subtypes, a significant reduced risk of 13% [RR = 0.87, 95% CI = 0.78-0.96] for cerebral infarction and a significant reduced risk of 17% [RR = 0.83, 95% CI = 0.71-0.97] for hemorrhagic stroke.

The investigators found in the stratified analysis by gender, a significant reduced risk of 13% of total stroke for male [RR = 0.87, 95% CI = 0.79-0.97] and a significant reduced risk of 16% of total stroke for female [RR = 0.84, 95% CI = 0.74-0.94].

The investigators found a significant reduced risk of 44% for studies with follow-up durations of 10 years [RR = 0.56, 95% CI = 0.37-0.85].

The investigators found a significant reduced risk of 15% for studies with follow-up durations of ≥10 years [RR = 0.85, 95% CI = 0.79-0.91].

The investigators found in 7 reports from 6 studies a nonlinear correlation between chocolate intake and risk of stroke [p for nonlinearity = 0.001].

The investigators found in dose-response meta-analysis, compared with no intake, a significant reduced risk of 9% for stroke for 1 serving chocolate per week [RR = 0.91, 95% CI = 0.86-0.97].   

The investigators found in dose-response meta-analysis, compared with no intake, a significant reduced risk of 13% for stroke for 3 servings chocolate per week [RR = 0.87, 95% CI = 0.81-0.94].   

The investigators found in dose-response meta-analysis, compared with no intake, a significant reduced risk of 15% for stroke for 7 servings chocolate per week [RR = 0.85, 95% CI = 0.76-0.93].   

The investigators found in dose-response meta-analysis, compared with no intake, a significant reduced risk of 17% for stroke for 10 servings chocolate per week [RR = 0.83, 95% CI = 0.72-0.94].   

The investigators found in 4 studies using “trim and fill” method, for the highest versus lowest intake of chocolate, a non-significant reduced risk of 8% for diabetes [pooled RR = 0.92, 95% CI = 0.78-1.08].

The investigators found in stratified analysis by sex, a significant reduced risk of 21% [RR = 0.79, 95% CI = 0.65-0.96] for men and a non-significant reduced risk of 8% [RR = 0.92, 95% CI = 0.72-1.17] for women.
Similarly, the risks of diabetes were not different between subsets of studies with follow-up durations of below or over 10 years [p for interaction = 0.51].

The investigators found in dose-response meta-analysis of 6 reports, a curvilinear association between chocolate intake and risk of diabetes [p for nonlinearity 0.001].

The investigators found in dose-response meta-analysis, compared with no intake, a significant reduced risk of 20% for diabetes for 1 serving chocolate per week [RR = 0.80, 95% CI = 0.71-0.91]. Significant means that there is an association with a 95% confidence.

The investigators found in dose-response meta-analysis, compared with no intake, a significant reduced risk of 24% for diabetes for 3 servings chocolate per week [RR = 0.76, 95% CI = 0.63-0.91]. Significant because RR of 1 was not found in the 95% CI of 0.63 to 0.91. RR of 1 means no risk/association.

The investigators found in dose-response meta-analysis, compared with no intake, a non-significant reduced risk of 17% for diabetes for 7 servings chocolate per week [RR = 0.83, 95% CI = 0.67-1.03]. Non-significant means it cannot be said with a 95% confidence that 7 servings chocolate per week really decreased the risk of diabetes with 17%.

The investigators found in dose-response meta-analysis, compared with no intake, a non-significant reduced risk of 11% for diabetes for 10 servings chocolate per week [RR = 0.89, 95% CI = 0.69-1.16].   

The investigators found in general, the dose-response pattern was J-shaped and the peak reduction in diabetes risk occurred at an intake of 2 servings/week [RR = 0.75, 95% CI = 0.63-0.89], with no protective effects observed when consuming chocolate > 6 servings/week.

The investigators concluded that chocolate consumption confers reduced risks of coronary heart disease, stroke and diabetes. Consuming chocolate in moderation (1-6 servings/week or 30-180g) may be optimal for the prevention of these burdensome diseases. However, additional large prospective studies are required to confirm the observed benefits of chocolate in populations with different characteristics and to establish the optimum frequency of chocolate intake for preventing cardiometabolic disease.

Original title:
Chocolate Consumption and Risk of Coronary Heart Disease, Stroke, and Diabetes: A Meta-Analysis of Prospective Studies by Yuan S, Li X, […], Lu J.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5537803/

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Objectives:
The association between vitamin D deficiency and early spontaneous pregnancy loss (SPL) is unclear. Therefore, this review article (meta-analysis) has been conducted.

Does a vitamin D deficiency increase risk of early spontaneous pregnancy loss?

Study design:
This review article included 5 studies (case-control and cohort studies), including 10,630 pregnant women.

Results and conclusions:
The investigators found no significant association between a low 25(OH)D level (vitamin D level in blood) and an increased risk of early spontaneous pregnancy loss.

However, the investigators found in subgroup analysis, an extremely low 25(OH)D level (20 ng/mL) was significantly associated with an 124% increased risk of early spontaneous pregnancy loss in the first trimester [relative risk = 2.24, 95% CI = 1.15-4.37, I2 = 0.0%, p = 0.355].

The investigators concluded that severe vitamin D deficiency (20 ng/mL) could be detrimental to early embryonic development and increases risk of early spontaneous pregnancy loss.

Original title:
Meta-analysis of the effect of the maternal vitamin D level on the risk of spontaneous pregnancy loss by Zhang H, Huang Z, [...], Wei Y.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28500757

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Objectives:
Are there differences in serum ceruloplasmin levels between patients with preeclampsia and healthy controls?

Study design:
This review article included 15 studies, with a total number of 1927 women.

Results and conclusions:
The investigators found that maternal serum ceruloplasmin concentration was significantly higher in preeclamptic than in the healthy pregnant women [MD = 12.57 mg/dL, 95% CI = 8.81 to 16.33].

The investigators found that ceruloplasmin levels were significantly higher both in mild [MD = 13.8 mg/dL, 95% CI = 2.64 to 23.53] and severe [MD = 21.84 mg/dL, 95% CI = 0.97 to 42.71] preeclampsia, when compared to the control group.

The investigators found that the severity of the disease did not significantly affect the levels of protein [MD = -9.34 mg/dL, 95% CI = -20.93 to 2.26].

The investigators concluded that serum ceruloplasmin may be a useful screening and follow-up tool for the evaluation of pregnant women with an indicative history of developing preeclampsia. Future studies are needed to evaluate the levels of this specific protein throughout the pregnancy course and provide data on its sensitivity and specificity by introducing cut-off values.

Original title:
Serum ceruloplasmin levels in preeclampsia: a meta-analysis by Bellos I, Papantoniou N and Pergialiotis V.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28605950

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Ceruloplasmin carries 65% to 90% of the copper found in blood.

Objectives:
The clinical benefits of perioperative antioxidant vitamin therapy in cardiac patients remain controversial. Therefore, this review article (meta-analysis) has been conducted.

Do patients undergoing cardiac surgery benefit from perioperative antioxidant vitamin therapy?

Study design:
This review article included 12 RCTs with 1584 cardiac patients.

Results and conclusions:
The investigators found compared with placebo or no antioxidant vitamin therapy that administration of antioxidant vitamin therapy resulted in a significant reduction:
-in postoperative atrial fibrillation (POAF) [RR = 0.55, 95% CI = 0.42 to 0.73, p  0.0001];
-duration of hospital stay [MD = -0.68, 95% CI = -0.98 to -0.39, p  0.00001];
-intensive care unit length of stay [MD = -0.21, 95% CI = -0.30 to -0.12, p  0.00001] and;      
-intubation time [MD = -2.41, 95% CI = -3.83 to -0.98, p = 0.001].

The investigators also found a trend towards a decrease in postoperative complications [RR = 0.72, 95% CI = 0.48-1.08, p = 0.11] and duration of postoperative atrial fibrillation [MD = -1.950, 95% CI = -3.28 to 0.29, p = 0.10].

The investigators concluded that perioperative antioxidant vitamin therapy in patients undergoing cardiac surgery reduces the incidence of postoperative atrial fibrillation, duration of hospital stay, intensive care unit length of stay and intubation time.

Original title:
The clinical benefits of perioperative antioxidant vitamin therapy in patients undergoing cardiac surgery: a meta-analysis by Geng J, Qian J, […], Shen Z.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28645181

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Objectives:
Studies implicate choline and betaine metabolite trimethylamine N-oxide (TMAO) in cardiovascular disease (CVD). Therefore, this review article (meta-analysis) has been conducted.

Is there an association between choline and betaine dietary intake and cardiovascular disease?

Study design:
This review article included a total of 6 prospective cohort studies comprising 18,076 incident cardiovascular disease events, 5,343 cardiovascular disease deaths among 184,010 participants.

There was no evidence for heterogeneity among studies.
Only 2 studies provided data on phosphatidylcholine and cardiovascular disease mortality.

Results and conclusions:
The investigators found in random effects meta-analysis, incident cardiovascular disease was not associated with choline [RR = 1.00, 95% CI = 0.98-1.02] or betaine [RR = 0.99, 95% CI = 0.98-1.01] dietary intake.
Results did not vary by study outcome (incident coronary heart disease, stroke, total cardiovascular disease).

The investigators found random effects meta-analysis did not support an association between choline and cardiovascular disease mortality [RR = 1.09, 95% CI = 0.89-1.35], but one study supported a positive association and there was significant heterogeneity [I2 = 84%, p 0.001].

The investigators concluded that there is no association between dietary choline/betaine intake with incident cardiovascular disease, but further research into choline and cardiovascular disease mortality are needed.

Original title:
Dietary Choline and Betaine and Risk of CVD: A Systematic Review and Meta-Analysis of Prospective Studies by Meyer KA and Shea JW.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28686188

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Objectives:
Controversy exists on the association between alcohol consumption and risk of heart failure (HF). Therefore, this review article (meta-analysis) has been conducted.

Is there an association between alcohol consumption and risk of heart failure?

Study design:
This review article included a total of 13 prospective cohort studies, with 13,738 heart failure cases among 355,804 participants.

Results and conclusions:
The investigators found light alcohol drinking (0.1-7 drinks/week) significantly reduced risk of heart failure with 14% [RR = 0.86, 95% CI = 0.81-0.90]. However, there was no statistically significant association between moderate (7.1-14 drinks/week), high (14.1-28 drinks/week), or heavy (>28 drinks/week) alcohol consumption and heart failure risk.

The investigators found former drinking significantly increased risk of heart failure with 22% [RR = 1.22, 95% CI = 1.11-1.33] compared with never or occasional drinking.

The investigators concluded that light alcohol drinking (0.1-7 drinks/week) is associated with a lower risk of heart failure, while former drinking is associated with a higher risk of heart failure.

Original title:
Alcohol consumption and risk of heart failure: Meta-analysis of 13 prospective studies by Susanna C. Larsson, […], Alicja Wolk

Link:
http://www.sciencedirect.com/science/article/pii/S0261561417301681

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Objectives:
Epidemiological studies evaluating the associations between serum copper and ratios of copper/zinc (Cu/Zn) and the preeclampsia (PE) risk in Asian population have produced inconsistent results. Therefore, this review article (meta-analysis) has been conducted.

Do a higher serum copper and ratios of Cu/Zn increase the preeclampsia risk in Asian population?

Study design:
This review article included relevant studies up to November 2016.
Pooled standardized mean difference (SMD) was calculated with random effects model.

Results and conclusions:
The investigators found that preeclampsia patients significantly had a higher serum copper level [SMD = 1.05, 95% CI = 0.34 to 1.77, I2 = 96.9%, p 0.0001] compared with healthy pregnancy controls.

The investigators found in subgroup analyses, a higher serum copper level in preeclampsia patients was observed in case-control studies [SMD = 1.39, 95% CI = 0.44 to 2.34]. However, no significant difference was found between preeclampsia patients and healthy pregnancy controls for ratios of Cu/Zn [SMD = 0.26, 95% CI = -0.77 to 1.29, I2 = 95.8%, p 0.0001].

The investigators concluded that a higher serum copper level is associated with an increased risk of preeclampsia in Asian population. However, further studies are needed to confirm these results.

Original title:
High serum copper level is associated with an increased risk of preeclampsia in Asians: A meta-analysis by Song X, Li B, [...], Zhang D.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28385285

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Objectives:
Low glycaemic index (GI) diets are beneficial in the management of hyperglycemia. Cardiovascular diseases are the major cause of mortality in diabetes therefore it is important to understand the effects of GI on blood lipids. Therefore, this review article has been conducted.

Does a low GI diet lower the cholesterol levels?

Study design:
This review article included 28 RCTs comparing low with high GI diets over at least 4 weeks. These 28 RCTs contained 1272 participants with studies ranged from 6 to 155 participants, one was powered on blood lipids and 3 had adequate allocation concealment.

Results and conclusions:
The investigators found that compared to high GI diet low GI diet significantly reduced total cholesterol by 0.13 mmol/L [95% CI = -0.22 to -0.04, p = 0.004, 27 trials, 1441 participants]. Significantly means, it can be said with 95% confidence that low GI diet really lowered the total cholesterol levels with 0.13 mmol/L.

The investigators found that compared to high GI diet low GI diet significantly reduced LDL-cholesterol by 0.16 mmol/L [95% CI = -0.24 to -0.08, p 0.0001, 23 studies, 1281 participants]. Significantly, because the p-value was less than 0.05.

The investigators found subgroup analyses suggested that reductions in LDL-cholesterol were greatest in studies of shortest duration and greatest magnitude of GI reduction. Furthermore, lipid improvements appeared greatest and most reliable when the low GI intervention was accompanied by an increase in dietary fiber.

The investigators found sensitivity analyses, removing studies without adequate allocation concealment, lost statistical significance but retained suggested mean falls of 0.10 mmol/L in both.

The investigators found no effects on HDL-cholesterol [MD = -0.03 mmol/L, 95% CI = -0.06 to 0.00, I2 = 0%], or triglycerides [MD was 0.01 mmol/L, 95% CI = -0.06 to 0.08, I2 = 0%].

The researchers concluded that low GI diets reduce total and LDL-cholesterol (bad cholesterol) but had no effect on HDL-cholesterol (good cholesterol) or triglycerides.

Original title:
Low glycemic index diets and blood lipids: A systematic review and meta-analysis of randomized controlled trials by Goff LM, Cowland DE, [...], Frost GS.

Link:
http://www.sciencedirect.com/science/article/pii/S0939475312001524

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High LDL-cholesterol levels and high triglyceride levels increase the risk of getting cardiovascular diseases whereas high HDL-cholesterol levels decrease the risk of getting cardiovascular diseases.

A low GI diet is a diet with a GI value of 55 or lower.

Objectives:
Recent evidence has suggested that flavonoid and lignan intake may be associated with decreased risk of chronic and degenerative diseases. Therefore, this review article (meta-analysis) has been conducted.

Does dietary flavonoid intake reduce risk of all-cause and cardiovascular disease mortality?

Study design:
This review article included 22 prospective cohort studies.

Results and conclusions:
The investigators found when compared with lower consumption, high consumption of total flavonoids was associated with a significant decreased risk of 26% for all-cause mortality [risk ratio = 0.74, 95% CI = 0.55-0.99].

The investigators found a 100-mg/day increment in dietary total flavonoids intake led to a (linear) decreased risk of 6% and 4% of all-cause and cardiovascular disease mortality, respectively.

The investigators found among flavonoid classes, significant results were obtained for intakes of flavonols, flavones, flavanones, anthocyanidins and proanthocyanidins.

The investigators found limited evidence was available on lignans intake and all-cause mortality.

The investigators concluded that higher dietary flavonoids intakes - at least 100-mg/day of flavonols, flavones, flavanones, anthocyanidins or proanthocyanidins - are associated with decreased risk of all-cause and cardiovascular disease mortality.

Original title:
Dietary Flavonoid and Lignan Intake and Mortality in Prospective Cohort Studies: Systematic Review and Dose-Response Meta-Analysis by Grosso G, Micek A, […], Giovannucci EL.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28472215

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Objectives:
Zinc sulfate may be a promising approach to treat neonatal jaundice. However, the results remain controversial. Therefore, this review article (meta-analysis) has been conducted.

Does zinc sulfate supplementation reduce neonatal jaundice?

Study design:
This review article included 5 RCTs involving 645 patients.

Results and conclusions:
The investigators found overall, compared with placebo, zinc sulfate supplementation failed to significantly reduce total serum bilirubin on 3 days [mean difference = 0.09 mg/dL, 95% CI = -0.49 to 0.67, p = 0.77]. Non-significant because p-value of 0.77 was greater than p-value of 0.05.

The investigators found overall, compared with placebo, zinc sulfate supplementation failed to significantly reduce total serum bilirubin on 7 days [mean difference= -0.37 mg/dL, 95% CI= -98 to 0.25, p  = 0.25].

The investigators found overall, compared with placebo, zinc sulfate supplementation failed to significantly reduce the incidence of hyperbilirubinemia [OR = 1.14, 95% CI = 0.74 to 1.76, p = 0.56].

The investigators found overall, compared with placebo, zinc sulfate supplementation showed no influence on phototherapy requirement [OR = 0.90, 95% CI = 0.41 to 1.98, p = 0.79]. Non-significant because OR of 1 was found in the OR of 0.41 to 1.98. OR of 1 means no risk/association.

The investigators found overall, compared with placebo, zinc sulfate supplementation significantly decreased duration of phototherapy [mean difference = -16.69 h, 95% CI = -25.09 to -8.3 h, p 0.000].

The investigators concluded zinc sulphate supplementation does not reduce the total serum bilirubin on 3 days and 7 days, the incidence of hyperbilirubinemia and phototherapy requirement, but significantly decreases duration of phototherapy.

Original title:
The influence of zinc sulfate on neonatal jaundice: a systematic review and meta-analysis by Yang L, Wu, [...], Tang J.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28372469

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Neonatal jaundice occurs when a baby has a high level of bilirubin in the blood. Bilirubin is a yellow substance that the body creates when it replaces old red blood cells. The liver helps break down the substance so it can be removed from the body in the stool.

A high level of bilirubin makes a baby's skin and whites of the eyes look yellow. This is called neonatal jaundice.

Jaundice is a common and usually harmless condition in newborn babies.
The symptoms of neonatal jaundice usually develop 2 to 3 days after the birth and tend to get better without treatment by the time the baby is about 2 weeks old.

Objectives:
The association between elevated serum phosphorus concentration and cardiovascular or all-cause mortality yielded conflicting results. Therefore, this review article (meta-analysis) has been conducted.

Does an elevated serum phosphorus concentration increase cardiovascular and all-cause mortality in the general population?

Study design:
This review article included 6 prospective cohort studies involving 120,269 subjects.

Results and conclusions:
The investigators found when compared the highest with the reference concentration of serum phosphorus, a significant increased risk of 36% for cardiovascular mortality [pooled RR = 1.36, 95% CI = 1.07-1.72]. Significant because RR of 1 was not found in the 95% CI of 1.07 to 1.72. RR of 1 means no risk/association.

The investigators found when compared the highest with the reference concentration of serum phosphorus, a significant increased risk of 33% for all-cause mortality [pooled RR = 1.33, 95% CI = 1.15-1.58]. Significant means that there is an association with a 95% confidence.

The investigators found stratified analyses revealed that elevated serum phosphorus significantly increased all-cause mortality risk with 33% among men [RR 1.33, 95% CI = 1.11-1.60], but not in women [RR = 1.09, 95% CI = 0.89-1.33].

The investigators concluded elevated serum phosphorus concentration is independently associated with excessive risk of cardiovascular and all-cause mortality in the general population without chronic kidney disease. Serum phosphorus on all-cause mortality risk appears to be pronounced in men but exhibits no clear effect on women. However, gender difference of elevated serum phosphorus on mortality risk should be verified by more prospective cohort studies.

Original title:
Serum phosphorus, cardiovascular and all-cause mortality in the general population: A meta-analysis by Bai W, Li J and Liu J.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/27475981

Additional information of El Mondo:
Find more studies/information on elderly and phosphorus right here.

Objectives:
Increased dietary potassium intake is thought to be associated with low blood pressure (BP). Whether potassium supplementation may be used as an antihypertensive agent is a question that should be answered. Therefore, this review article (meta-analysis) has been conducted.

Does potassium supplementation reduce blood pressure among patients with essential hypertension (SBP ≥140 mmHg and DBP ≥90 mmHg)?

Study design:
This review article included 23 trials (9 parallel and 14 crossover randomized placebo-controlled clinical trials with a minimum of 4 weeks of therapy to ensure that the intervention had sufficient time to produce an effect) involving 1,213 patients with essential hypertension (SBP ≥140 mmHg and DBP ≥90 mmHg).

The result of meta-regression revealed that the association between potassium dosage, follow-up period and mean age were not statistically significant; therefore they did not play an important role in the heterogeneity across studies.

There was no publication bias.

Results and conclusions:
The investigators found that potassium supplementation significantly reduced systolic blood pressure (SBP) of patients with essential hypertension with 4.25 mmHg [95% CI = -5.96 to -2.53, I2 = 41%].

The investigators found that potassium supplementation significantly reduced diastolic blood pressure (DBP) of patients with essential hypertension with 2.53 mmHg [95% CI = -4.05 to -1.02, I2 = 65%].

The investigators found in 8 RCTs when compared to baseline, the mean changes in systolic blood of patients with essential hypertension was -8.89 mmHg [95% CI = -13.67 to -4.11] significantly higher in the intervention group (group taking potassium supplements) than the control group. 

The investigators found in 8 RCTs when compared to baseline, the mean changes in diastolic blood pressure of patients with essential hypertension was -6.42 mmHg [95% CI = -10.99 to -1.84] significantly higher in the intervention group (group taking potassium supplements) than the control group. 

The investigators found in subgroup analysis that the mean difference in systolic blood of patients with essential hypertension was -2.64 mmHg [95% CI = -5.25 to -0.03] in America, -4.56 mmHg [95% CI = -6.51 to -2.62) in Europe and -5.21 mmHg [95% CI = -9.63 to -0.79] in Asia.

The investigators found a dose-response relationship between potassium intake and reduction in systolic and diastolic blood pressure (low-dose (50 mmol/day), moderate-dose (50-99 mmol/day) and high-dose (≥100 mmol/day)).

The investigators concluded that potassium supplementation for at least 4 weeks reduces blood pressure of patients with essential hypertension and therefore, can be recommended as an adjuvant antihypertensive agent for patients with essential hypertension (SBP ≥140 mmHg and DBP ≥90 mmHg).

Original title:
Oral potassium supplementation for management of essential hypertension: A meta-analysis of randomized controlled trials by Poorolajal J, Zeraati F, […], Maleki A.

Link:
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0174967

Additional information of El Mondo:
Find more information/studies on hypertension and potassium right here.

Objectives:
An increased intake of magnesium might lower blood pressure (BP), yet evidence from clinical trials is inconsistent, perhaps as a result of small sample size or heterogeneity in study design. Therefore, this review article (meta-analysis) has been conducted.

Are there dose-dependent effects of magnesium supplementation on blood pressure?

Study design:
This review article included 20 RCTs included 14 of hypertensive and 6 of normotensive persons totaling 1220 participants.
The doses of magnesium ranged from 10 to 40 mmol/day (median: 15.4 mmol/day or 370 mg per day).

Results and conclusions:
The investigators found magnesium supplementation resulted in only a small overall non-significant reduction in blood pressure. The pooled net estimates of blood pressure change were -0.6 mmHg [95% CI = -2.2 to 1.0] for systolic blood pressure and -0.8 mmHg [95% CI = -1.9 to 0.4] for diastolic blood pressure.

However, the investigators found an apparent dose-dependent effect of magnesium, with significant reductions of 4.3 mmHg systolic blood pressure [95% CI = 6.3 to 2.2, p 0.001) and non-significant reductions of 2.3 mmHg diastolic blood pressure [95% CI = 4.9 to 0.0, p = 0.09) for each 10 mmol/day (240 mg/day) increase in magnesium dose.

The investigators concluded there is a dose-dependent blood pressure reductions, especially systolic blood pressure from magnesium supplementation. However, adequately powered trials with sufficiently high doses of magnesium supplements need to be performed to confirm this relationship.

Original title:
The effect of magnesium supplementation on blood pressure: a meta-analysis of randomized clinical trials by Jeea SH, Miller ER, [...], Klagb MJ.

Link:
http://www.sciencedirect.com/science/article/pii/S0895706102029643

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

Objectives:
The findings of prospective cohort studies are inconsistent regarding the association between dietary magnesium intake and serum magnesium concentration and the risk of hypertension. Therefore, this review article (meta-analysis) has been conducted.

Do dietary magnesium intake and serum magnesium concentrations reduce risk of hypertension?

Study design:
This review article included 10 cohort studies, including 20,119 cases of hypertension and 180,566 participants.

The range of dietary magnesium intake was 96-25 mg/day and serum magnesium levels were 0.66-0.95 mmol/L.

The funnel plot showed reasonable symmetry, with no evidence of publication bias (Egger’s test p = 0.95 and Begg’s test p = 0.71).

Results and conclusions:
The investigators found when comparing the highest to the lowest category of dietary magnesium consumption, a significant reduced risk of 8% for hypertension [pooled RR = 0.92, 95% CI = 0.86-0.98].

The investigators found for every 100 mg/day increment in dietary magnesium intake a significant reduced risk of 5% for hypertension [pooled RR = 0.95, 95% CI = 0.90-1.00, I2 = 39.3%, p = 0.13].
The reduced hypertension risk associated with 100 mg/day was tended to be observed when the duration of follow-up was more than 8 years and when the results were adjusted separately for calcium, sodium, fiber, cholesterol, saturated fat intake or smoking.

The investigators found the dose-response meta-analysis suggested a marginal linear relationship between dietary magnesium intake and hypertension risk [p for linearity = 0.057].

The investigators found no association between serum magnesium concentrations and reduced risk of hypertension [pooled RR = 0.91, 95% CI = 0.80-1.02, p = 0.10, I2 = 0%, p = 0.48].

The investigators concluded that increased dietary magnesium intake is associated with lower risk of hypertension in a linear dose-response pattern. However, there is no association between serum magnesium concentration and risk of hypertension.

Original title:
Dose-response relationship between dietary magnesium intake, serum magnesium concentration and risk of hypertension: a systematic review and meta-analysis of prospective cohort studies by Han H, Fang X, […], Cao Y.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5420140/

Additional information of El Mondo:
Find more information/studies on hypertension and magnesium right here.

Objectives:
Heart failure (HF) remains a major health problem affecting 5.7 million adults in USA. Data on the association of egg consumption with incident heart failure have been inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Does egg consumption increase incident heart failure in the general population?

Study design:
This review article included 4 prospective cohort studies with a total of 105,999 subjects and 5,059 cases of new onset heart failure.

There was no evidence of publication bias on funnel plot analysis as supported by the Egger’s test (p = 0.68).

Results and conclusions:
The investigators found when comparing the highest (≥1/day) to the lowest category of egg consumption, a significant increased risk of 25% [pooled RR = 1.25, 95% CI = 1.12-1.39, p = 0.00, I2 = %] for heart failure.

The investigators found that sensitivity analysis (stratification by excluding studies with men/women, 20 years of follow-up duration, US/Non-US studies) did not alter the main conclusion.

The investigators concluded that at least 1 egg per day increases heart failure risk in the general population. Further studies are warranted to explore the underlying biological mechanisms.

Original title:
Egg Consumption and Incidence of Heart Failure: A Meta-Analysis of Prospective Cohort Studies by Khawaja O, Singh H, […], Djoussé L.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5367008/

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

Objectives:
Does a low salt intake reduce blood pressure?

Study design:
This review article included 34 randomized trials with 3230 participants (the median age was 50 (range 22-73)), of which 22 were in hypertensive individuals and 12 in normotensive individuals. Of the 34 trials, 23 used crossover design and 11 used paralleled comparisons. 22 of the 34 trials were double blind, in 11 the observer was blind to blood pressure and one did not report any blinding procedure.

The study duration varied from 4 weeks to 3 years (median 4 weeks). With the usual salt intake the median 24 hour urinary sodium was 160 mmol (range 125-200 mmol), equivalent to a salt intake of 9.4 g/day (range 7.3-11.7 g/day) and the median blood pressure was 141/86 mmHg.

Despite the fact that only 7 out of 34 trials performed intention to treat analysis, the percentage of participants lost to follow-up after randomization was small (6.7% on average).

Results and conclusions:
The investigators found meta-analysis showed that the mean change in urinary sodium (reduced salt v usual salt) was -75 mmol/24 h (equivalent to a reduction of 4.4 g/day salt), and with this reduction in salt intake, the mean change in blood pressure was -4.18 mmHg [95% CI = -5.18 to -3.18, I2 = 75%] for systolic blood pressure and -2.06 mmHg [95% CI = -2.67 to -1.45, I2 = 68%] for diastolic blood pressure.

The investigators found meta-regression showed that age, ethnic group, blood pressure status (hypertensive or normotensive) and the change in 24 hour urinary sodium were all significantly associated with the fall in systolic blood pressure, explaining 68% of the variance between studies.

The investigators found a 100 mmol reduction in 24 hour urinary sodium (equivalent to a reduction 6 g/day salt) was associated with a fall in systolic blood pressure of 5.8 mmHg [95% CI = -2.5 to -9.2,  p = 0.001] after adjustment for age, ethnic group and blood pressure status.
For diastolic blood pressure, age, ethnic group, blood pressure status and the change in 24 hour urinary sodium explained 41% of the variance between studies.

The investigators found meta-analysis by subgroup showed that in people with hypertension the mean effect was -5.39 mmHg [95% CI = -6.62 to -4.15, I2 = 61%] for systolic blood pressure and -2.82 mmHg [95% CI = -3.54 to -2.11, I2 = 52%] for diastolic blood pressure.
In normotensive people, the figures were -2.42 mmHg [95% CI = -3.56 to -1.29, I2 = 66%] and -1.00 mmHg [95% CI = -1.85 to -0.15, I2 = 66%], respectively.

The investigators found further subgroup analysis showed that the decrease in systolic blood pressure was significant in both white and black people and in men and women.

The investigators found meta-analysis of data on hormones and lipids showed that the mean change was:
0.26 ng/mL/h [95% CI = 0.17 to 0.36, I2 = 70%] for plasma renin activity;
73.20 pmol/L [95% CI = 44.92 to 101.48, I2 = 62%] for aldosterone;
187 pmol/L [95% CI = 39 to 336, I2 = 5%] for noradrenaline (norepinephrine);
37 pmol/L [95% CI = -1 to 74, I2 = 12%] for adrenaline (epinephrine);
0.05 mmol/L [95% CI = -0.02 to 0.11, I2 = 0%] for total cholesterol;
0.05 mmol/L [95% CI = -0.01 to 0.12, I2 = 0%] for low density lipoprotein cholesterol (LDL-cholesterol or bad cholesterol);
-0.02 mmol/L [95% CI = -0.06 to 0.01, I2 = 16%] high density lipoprotein cholesterol (HDL-cholesterol or good cholesterol) and:
0.04 mmol/L [95% CI = -0.02 to 0.09, I2 = 0%] for triglycerides.

The investigators concluded a modest reduction in salt intake of 4.4 g/day for 4 or more weeks causes, from a population viewpoint, important falls in blood pressure in people with both raised and normal blood pressure.
Salt reduction is associated with a small physiological increase in plasma renin activity, aldosterone and noradrenaline and no significant change in lipid concentrations.
The current recommendations to reduce salt intake from 9-12 to 5-6 g/day will have a major effect on blood pressure, but a further reduction to 3 g/day will have a greater effect and should become the long term target for population salt intake.

Original title:
Effect of longer term modest salt reduction on blood pressure: Cochrane systematic review and meta-analysis of randomised trials by He FJ, Li J and MacGregor GA.

Link:
http://www.bmj.com/content/346/bmj.f1325

Additional information of El Mondo:
Find more studies/information on sodium intake and hypertension right here.
A daily diet with a maximum of 3 grams salt per day is a diet with a maximum of 0.15 gram salt per 100 kcal.
A daily diet with a maximum of 0.15 gram salt per 100 kcal is a diet with mainly products/meals with a maximum of 0.15 gram salt per 100 kcal.

Objectives:
Approximately 5.7 million Americans carry the diagnosis of systolic heart failure (HF), a major health care burden. Heart failure is a known manifestation of thiamine deficiency (TD). Therefore, this review article has been conducted.

Is thiamine deficiency (vitamin B1 deficiency) a risk factor of systolic heart failure?

Study design:
This review article included 9 studies (observational studies and RCTs).

Results and conclusions:
The investigators found systolic heart failure patients had a higher risk of 153% of getting a thiamine deficiency [odds ratio = 2.53, 95% CI = 1.65-3.87].

The investigators found diuretic use, changes in dietary habits and altered thiamine absorption and metabolism were identified as possible mechanisms of thiamine deficiency in heart failure patients.

The investigators found small observational studies and randomized control trials suggested that thiamine supplementation in heart failure population could improve ejection fraction and reduce symptoms.

The investigators concluded thiamine deficiency is more prevalent in heart failure population, and its supplementation may be beneficial. The therapeutic role of thiamine in heart failure warrants further study.

Original title:
Determining the Role of Thiamine Deficiency in Systolic Heart Failure: A Meta-Analysis and Systematic Review by Jain A, Mehta R, […], Winchester DE.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/26497757

Additional information of El Mondo:
Find more information/studies on cardiovascular disease and vitamin B1 (thiamine) right here.

Objectives:
Previous systematic reviews and meta-analyses have evaluated the association of dairy consumption and the risk of cardiovascular disease (CVD). However, the findings were inconsistent. No quantitative analysis has specifically assessed the effect of yogurt intake on the incident risk of cardiovascular disease. Therefore, this review article (meta-analysis) has been conducted.

Is yogurt intake associated with a lower incident risk of cardiovascular disease?

Study design:
This review article included 9 prospective cohort studies involving a total of 291,236 participants. Follow-up durations ranged between 10.2 and 17.3 years. The baseline age of the participants ranged from ≥21 to ≥55 years. Yogurt intake was assessed by a food-frequency questionnaire (FFQ).

There was no publication bias.

Results and conclusions:
The investigators found when compared with the lowest category, highest category of yogurt consumption was not significantly related with the incident risk of cardiovascular disease [RR = 1.01, 95% = 0.95-1.08, I2 = 52%]. Not significantly because RR of 1 was found in the 95% CI of 0.95 to 1.08. RR of 1 means no risk/association.

The investigators found in the stratified analysis by type of outcome, the pooled RR of yogurt consumption was 1.04 [95% = 0.95 to 1.15] for CHD, RR = 1.02 [95% CI = 0.92 to 1.13] for stroke and RR = 0.87 [95% CI = 0.77 to 0.98] for the incident CVD events.

However, the investigators found intake of ≥200 g/day yogurt was significantly associated with a lower risk of 8% [RR = 0.92, 95% CI = 0.85 to 1.00] for cardiovascular disease in the subgroup analysis.

The investigators concluded that a daily dose of ≥200 g yogurt intake is associated with a lower incident risk of cardiovascular disease. Further cohort studies and randomized controlled trials are still demanded to establish and confirm the observed association in populations with different characteristics.

Original title:
Consumption of Yogurt and the Incident Risk of Cardiovascular Disease: A Meta-Analysis of Nine Cohort Studies by Wu L and Sun D.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5372978/

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

Objectives:
Does iron supplementation during pregnancy improve maternal haematological status and birth weight?

Study design:
This review article included 48 RCTs (17,793 women) and 44 cohort studies (1,851,682 women).

The dose of iron in RCTs ranged from 10 mg to 240 mg daily. Duration of supplementation varied from 7 to 8 weeks up to 30 weeks during pregnancy.

Significant heterogeneity existed for several outcomes that could not be explained substantially by pre-specified subgroups.

Results and conclusions:
The investigators found iron supplementation during pregnancy increased maternal mean haemoglobin concentration by 4.59 g/L [95% CI = 3.72 to 5.46] compared with controls.

The investigators found iron with folic acid was associated with a significant increase in mean haemoglobin concentration of 10.41 g/L [95% CI = 5.36 to 15.46, I2 = 0%, 9 trials] and reduction in risk of anaemia in the third trimester or at delivery of 56% [95% CI = 0.37 to 0.53, I2 = 44%, 5 trials]. Significant means there is an association with a 95% confidence.

The investigators found iron supplementation during pregnancy significantly reduced the risk of anaemia with 50% [95% CI = 0.42 to 0.59] compared with controls.

The investigators found iron supplementation during pregnancy significantly reduced the risk of iron deficiency (of the mother) with 41% [95% CI = 0.46 to 0.79] compared with controls.

The investigators found iron supplementation during pregnancy significantly reduced the risk of iron deficiency anaemia with 60% [95% CI = 0.26 to 0.60] compared with controls.

The investigators found iron supplementation during pregnancy significantly reduced the risk of low birth weight (2500 g) with 19% [95% CI = 0.71 to 0.93] compared with controls.

However, the investigators found iron supplementation during pregnancy non-significantly reduced the risk of preterm birth with 16% [95% CI = 0.68 to 1.03] compared with controls. Non-significant means there is no association with a 95% confidence.

The investigators found in cohort studies that anaemia in the first or second trimester was significantly associated with a higher risk for low birth weight of 29% [adjusted odds ratio 1.29, 95% CI = 1.09 to 1.53] and preterm birth with 21% [adjusted odds ratio = 1.21, 95% CI = 1.13 to 1.30].

The investigators found in exposure-response analysis that for every 10 mg increase in iron dose/day, up to 66 mg/day, the relative risk of maternal anaemia was significantly 0.88 [95% CI = 0.84 to 0.92, p for linear trend 0.001].

The investigators found in exposure-response analysis that birth weight increased by 15.1 g [95% CI = 6.0 to 24.2, p for linear trend = 0.005] and risk of low birth weight significantly decreased by 3% [relative risk = 0.97, 95% CI = 0.95 to 0.98, p for linear trend 0.001] every 10 mg increase in dose/day.

Furthermore, the investigators found for each 1 g/L increase in mean haemoglobin, birth weight increased by 14.0 g [95% CI = 6.8 to 21.8, p for linear trend = 0.002]. However, mean haemoglobin was not associated with the risk of low birth weight and preterm birth.

The investigators found no evidence of a significant effect on duration of gestation, small for gestational age births and birth length and duration of iron use was not significantly associated with the outcomes after adjustment for dose.

The investigators concluded daily prenatal use of iron substantially improved birth weight in a linear dose-response fashion, probably leading to a reduction in risk of low birth weight. An improvement in prenatal mean haemoglobin concentration linearly increased birth weight and a linear decrease in maternal anaemia with higher doses of iron, up to 66 mg/day.

Original title:
Anaemia, prenatal iron use, and risk of adverse pregnancy outcomes: systematic review and meta-analysis by Haider BA, Olofin I, […], Fawzi WW.

Link:
http://www.bmj.com/content/346/bmj.f3443

Additional information of El Mondo:
Find more information/studies on iron and pregnancy right here.

Iron deficiency anaemia occurs when there isn't enough iron in the body. Anaemia is a condition where the amount of haemoglobin in the blood is below the normal level.
Iron deficiency anaemia has been defined as haemoglobin 110 g/L and serum ferritin 12 µg/L.

Objectives:
Previous systematic reviews suggest beneficial effects of flavonoids on biomarkers of cardiovascular disease (CVD) risk, but have overlooked the impact of dose response or food complexity. Therefore, this review article has been conducted.

Do taking flavonoid supplements improve flow-mediated dilation (FMD) and blood pressure?

Study design:
This review article included 63 RCTs.

Results and conclusions:
The investigators found meta-analyses of combined flavonoid subclasses showed significant improvements in FMD [chronic: 0.73%, 95% CI = 0.17 to 1.30, 14 RCTs and acute: 2.33%, 95% CI = 1.58 to 3.08, 18 RCTs].

The investigators found meta-analyses of combined flavonoid subclasses showed significant improvements in blood pressures [systolic: -1.46 mmHg, 95% CI = -0.38 to -0.53, 63 RCTs and diastolic: -1.25 mmHg, 95% CI = -1.82 to -0.67, 63 RCTs].

The investigators found similar benefits were observed for the flavan-3-ol, catechol flavonoids (catechins, quercetin, cyanidin etc.), procyanidins, epicatechin and catechin subgroups.

The investigators found dose-response relationships were non-linear for FMD (R2 ≤ 0.30), with greater associations observed when applying polynomial regression analyses (R2 ≤ 0.72). However, there was no indication of a dose response for blood pressure.

The investigators concluded flavonoid subclasses supplements show significant improvements in FMD and blood pressure. However, the flavonoid bioactivity does not follow a classical linear dose-response association and this may have important biological implications.

Original title:
Relative impact of flavonoid composition, dose and structure on vascular function: A systematic review of randomised controlled trials of flavonoid-rich food products by Kay CD, Hooper L, […], Cassidy A.

Link:
http://onlinelibrary.wiley.com/doi/10.1002/mnfr.201200363/abstract;jsessionid=2CCB9E4E779A221E42AA38998C865DA6.d02t03?deniedAccessCustomisedMessage=&userIsAuthenticated=false

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

The optimal blood pressure for a healthy adult is120 mmHg systolic pressure and 80 mmHg diastolic pressure.

When blood flow increases through a vessel, the vessel dilates. This phenomenon has been coined flow-mediated dilatation (FMD). Flow-mediated dilation is an accepted technique to quantify endothelial function and has shown to have prognostic value for future cardiovascular disease (CVD). 

Objectives:
Hypertension is a major risk factor for cardiovascular disease, myocardial infarction, stroke and renal failure. Sesame consumption may benefit blood pressure (BP) due to its high polyunsaturated fatty acids, fibre, phytosterol and lignans content. To clarify this association, this review article (meta-analysis) has been conducted.

Does sesame consumption reduce blood pressure?

Study design:
This review article included 8 controlled trials with a total of 843 participants.

Results and conclusions:
The investigators found that sesame consumption significantly reduced systolic blood pressure with 7.83 mmHg [95% CI = -14.12 to -1.54, p  0.05, I2 = 99%].

The investigators found that sesame consumption significantly reduced diastolic blood pressure with 5.83 mmHg [95% CI = -9.58 to -2.08, p  0.01, I2 = 98%].

However, to reduce the heterogeneity, the meta-analysis was limited to high methodology quality trials (n = 4), which resulted in a significant reduction of 3.23 mmHg in systolic blood pressure [95% CI = -5.67 to -0.79, I2 = 33%] and a non-significant reduction of 2.08 mmHg in diastolic blood pressure [95% CI = -4.85 to 0.69, I2 = 62%].

The investigators concluded that sesame consumption reduces the systolic blood pressure but not the diastolic blood pressure. However, further investigations with larger sample sizes and better methodology quality are required to confirm the blood pressure lowering effect of sesame consumption.

Original title:
Can sesame consumption improve blood pressure? A systematic review and meta-analysis of controlled trials by Khosravi-Boroujeni H, Nikbakht E, [...], Khalesi S.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28387047

Additional information of El Mondo:
Find more information/studies on cardiovascular diseases and how to reduce a high blood pressure right here.
 

Objectives:
The aim of this review article was to assess the relation between the level of habitual potassium intake and the incidence of cardiovascular disease (CVD).

Study design:
This review article included 15 cohort studies involving a total of 247510 male and female participants, 7,066 strokes, 3,058 coronary heart disease (CHD) events and 2,497 total CVD events.
The weighted average follow-up time was 12.2 years (range 5 to 19 years).
There was significant heterogeneity among studies in terms of sample size, duration of observation, number of events and difference in dietary potassium intake between the groups being compared. This heterogeneity led to a reduced statistical power in detecting a possible association between dietary potassium and coronary heart disease and cardiovascular disease.

There was no evidence of publication bias by the Egger test.

Potassium intake was assessed by 24-h dietary recall (n = 2), food frequency questionnaire (n = 6) or 24-h urinary excretion (n = 3).

Results and conclusions:
The investigators found in a pooled analysis, a dietary intake of 1.64g (42 mmol) potassium per day was significantly associated with a 21% lower risk of stroke [RR = 0.79, 95% CI = 0.68 to 0.90, p = 0.0007]. Significant means it can be said with a 95% confidence that a daily intake of 1.64g potassium really decreased the risk of having a stroke.

The investigators found a trend toward an inverse association between higher potassium intake (average weighted difference = 1.38g or 35.3 mmol/day) and risk of coronary heart disease [RR = 0.92, 95% CI = 0.81 to 1.04], which was not statistically significant [p = 0.18].
Not significant means it cannot be said with a 95% confidence that a daily intake of 1.38g potassium really decreased the risk of coronary heart disease with 8%. 

The investigators found a trend toward an inverse relationship between higher potassium intake (average weighted difference = 1.30g or 33.4 mmol/day) and cardiovascular disease risk [RR = 0.85, 95% CI = 0.62 to 1.16], which was not statistically significant [p = 0.31].

The investigators found a trend toward lower risk of CHD [RR = 0.93, 95% CI = 0.87 to 0.99, p = 0.03] and total CVD [RR = 0.74, 95% CI = 0.60 to 0.91, p = 0.0037] that attained statistical significance after the exclusion of a single cohort, based on sensitivity analysis.

The results of meta-regression analyses indicated that potassium intake difference, length of follow-up, quality score, recruitment year and population potassium intake at baseline were not significant sources of heterogeneity in the relationship of the potassium intake effect on the risk of CHD.

The results of meta-regression analyses indicated that the length of follow-up (coefficient: -0.064, 95% CI = -0.112 to -0.015, p = 0.01) and quality score (coefficient: -0.165, 95% CI = -0.287 to -0.043, p = 0.01) were significant sources of heterogeneity.

The investigators concluded that 1.64g dietary potassium per day decreases the risk of having a stroke and might also reduce the risk of coronary heart disease and total cardiovascular disease. This result applies to the general population, not only to specific subgroups at higher risk.
The favorable effects of dietary potassium were documented at least to some extent independently of other factors.
The results of this meta-analysis support recommendations for higher consumption of potassium-rich foods to prevent vascular diseases.

Original title:
Potassium Intake, Stroke, and Cardiovascular Disease : A Meta-Analysis of Prospective Studies by D'Elia L, Barba G, [...], Strazzullo P.

Link:
http://www.sciencedirect.com/science/article/pii/S0735109710049764

Additional information of El Mondo:
Find more information/studies on potassium right here.
The protective effect of potassium against the risk of stroke may conceivably relate to its blood pressure lowering effect.