Nutritional advice

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

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

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

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

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

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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

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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

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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:
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:
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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

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The protective effect of potassium against the risk of stroke may conceivably relate to its blood pressure lowering effect.

Objectives:
Does higher lycopene exposure decrease risk of cardiovascular diseases (CVD)?

Study design:
This review article included 14 observational studies.
Subgroup analyses showed that retrospective and low quality studies were statistically significant sources of heterogeneity.

Results and conclusions:
The investigators found higher lycopene exposure significantly reduced risk of cardiovascular diseases with 17% [pooled risk ratio = 0.83, 95% CI = 0.76-0.90]. Findings were similar restricting to dietary studies [RR = 0.87, 95% CI = 0.79-0.96] and biomarker studies [RR = 0.74, 95% CI = 0. 62-0.87].

The investigators found higher dietary lycopene intake significantly reduced risk of coronary heart disease with 13% [RR = 0.87, 95% CI = 0.76-0.98]. However, the reduced risk was not significant for higher lycopene biomarker concentrations.

The investigators found higher dietary lycopene intake significantly reduced risk of stroke with 17% [RR = 0.83, 95% CI = 0.69-0.96].

The investigators found higher lycopene biomarker concentrations significantly reduced risk of stroke with 35% [RR = 0.65, 95% CI = 0.42-0.87].

The investigators concluded both higher dietary lycopene intake and higher lycopene biomarker concentrations are inversely associated with a lower risk of cardiovascular diseases. Further well-designed randomized clinical trials are required to assess the role of lycopene on cardiovascular diseases.

Original title:
Lycopene and risk of cardiovascular diseases: A meta-analysis of observational studies by Song B, Liu K, […], Xu Y.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28318092

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Find more information/studies on cardiovascular diseases and lycopene right here.
Lycopene is a carotenoid and is responsible for the yellow colour in tomatoes. Carotenoids are antioxidants.

Objectives:
Does a high GI or GL diet increase risk of stroke events?

Study design:
This review article included 7 prospective cohort studies with 225000 participants free of diabetes from 6 different countries. 3046 stroke events were included and the follow-up range was 5 to 18 years.

Results and conclusions:
The investigators found a high GI diet was not significantly associated with a 10% increased risk for stroke events [pooled RR = 1.10, 95% CI = 0.99-1.21]. Not significantly means, there is no association with a 95% confidence.

However, the investigators found high GL was significantly associated with a 19% increased risk for stroke events [pooled RR = 1.19, 95% CI = 1.05-1.36].

The investigators found there was no significant association between high carbohydrate intake and stroke risk [RR = 1.12, 95% CI = 0.93-1.35].

The investigators concluded a daily high GL diet (but not GI diet) is the risk factor of stroke event. Further researches are needed to verify the meta-analyses results and study associated mechanisms.

Original title:
Carbohydrate Intake, Glycemic Index, Glycemic Load, and Stroke: A Meta-analysis of Prospective Cohort Studies by Cai X, Wang C, [...], Ding F.

Link:
http://www.ncbi.nlm.nih.gov/pubmed/25593213

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Objectives:
Does garlic supplementation reduce cardiovascular disease risk?

Study design:
This review article included original studies and previous review articles (meta-analyses).

Results and conclusions:
The investigators found in 4 meta-analyses and 2 original studies that garlic supplementation significantly reduced blood pressure by 7-16 mmHg (systolic) and 5-9 mmHg (diastolic). Significant means that there is an association with a 95% confidence.

The investigators found in 8 meta-analyses that garlic supplementation significantly reduced total cholesterol by 7.4-29.8 mg/dL.

The most consistent benefits were shown in studies that used aged garlic extract (AGE).

The investigators found a few small studies that used aged garlic extract also showed favourable effects on C-reactive protein (CRP), pulse wave velocity (PWV), and coronary artery calcium (CAC).

Although garlic is generally safe, rare adverse reactions have been documented with limited causality established.

The investigators concluded garlic supplementation has the potential for cardiovascular protection based on risk factor reduction (hypertension and total cholesterol) and surrogate markers (C-reactive protein, pulse wave velocity and coronary artery calcium) of atherosclerosis. Larger studies are warranted to evaluate these effects further.

Original title:
Garlic and Heart Disease by Varshney R and Budoff MJ.

Link:
http://jn.nutrition.org/content/146/2/416S.long

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

Objectives:
Increasing evidence suggests that the Mediterranean diet can reduce the risk of cardiovascular disease. Olive oil is the hallmark of this dietary pattern. Therefore, this review article has been conducted.

Does olive oil consumption reduce risk of cardiovascular disease?

Study design:
This review article included case-control, prospective cohort studies and a randomised controlled trial investigating the specific association between olive oil consumption and the risk of cardiovascular disease (101,460 participants) or stroke (38,673 participants). The results of all observational studies were adjusted for total energy intake.

Evidence of heterogeneity was apparent for cardiovascular disease, but not for stroke. Both the Egger test (p = 0.06) and the funnel plot suggested small-study effects.

Results and conclusions:
The investigators found in case-controle studies a non-significant reduced risk of 27% [relative risk = 0.73, 95% CI = 0.44-1.21] for cardiovascular disease for a 25g increase in olive oil consumption.

The investigators found in cohort studies a non-significant reduced risk of 4% [relative risk = 0.96, 95% CI = 0.78-1.18] for cardiovascular disease for a 25g increase in olive oil consumption.

The investigators found in cohort studies olive oil consumption significantly reduced risk of stroke with 26% [relative risk = 0.74, 95% CI = 0.60-0.92].

The investigators found random-effects model showed a significant reduced risk of 18% [RR = 0.82, 95% CI = 0.70, 0.96] for combining all cardiovascular events (CHD and stroke).

The investigators concluded available studies support an inverse association of olive oil consumption with stroke and with stroke and cardiovascular disease combined. This finding is in agreement with the recent successful results of the PREDIMED randomised controlled trial.

Original title:
Olive oil consumption and risk of CHD and/or stroke: a meta-analysis of case-control, cohort and intervention studies by Martínez-González MA, Dominguez LJ and Delgado-Rodríguez M.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/24775425

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Objectives:
What is the impact of antioxidants (N-acetylcysteine (NAC), polyunsaturated fatty acids (PUFAs) and vitamins) on incidence of postoperative atrial fibrillation (POAF) and duration of length of hospital stay?

Study design:
This review article included 23 RCTs that reported outcomes of 4278 patients undergoing cardiac surgery.
A total of 10 RCTs with 1,026 patients (513 cases were allocated to the NAC and 513 cases to the control group, with a mean age of 63.2 years and 76.8% being males), 8 RCTs with 2,687 patients (with a mean age of 64.17 years and 77.6% being males), and 5 RCTs with 565 patients (with a mean age of 65.17 years and 73.6% being males) investigated the effect of NAC, PUFA and antioxidant vitamins on POAF, respectively.

There was no publication bias.

Results and conclusions:
The investigators found pooled effects estimates on postoperative atrial fibrillation showed a significant reduction after:
NAC [OR = 0.56, 95% CI = 0.40-0.77, p 0.001, I2 = 15%, p = 0.3];
PUFA [OR = 0.84, 95% CI = 0.71-0.99, p = 0.03] and;
Vitamin C treatment [OR = 0.50, 95% CI = 0.27-0.91, p = 0.02, I2 = 50%].

The investigators found hospital length of stay was not significant reduced after NAC therapy [SMD = 0.082, 95% CI = -0.09 to 0.25, p = 0.3, I2 = 0.0%, p = 0.7], but could be significant decreased with PUFA [SMD = -0.185, 95% CI = -0.35 to -0.018, p = 0.03, I2 = 11%, p = 0.3] and vitamin C [SMD = -0.325, 95% CI = -0.50 to -0.14, p 0.01, I2 = 60.4%, p = 0.056].
Significant because the p-values were less than the p-value of 0.05.

The investigators concluded perioperative antioxidant supplementations with N-acetylcysteine, polyunsaturated fatty acids and vitamin C prevent atrial fibrillation after cardiac surgery. Moreover, polyunsaturated fatty acids and vitamin C are capable to reduce hospital stay, whereas N-acetylcysteine lacks this capacity.

Original title:
Antioxidant supplementations for prevention of atrial fibrillation after cardiac surgery: an updated comprehensive systematic review and meta-analysis of 23 randomized controlled trials by Ali-Hassan-Sayegha S, Mirhosseinia SJ, […], Liakopoulose OJ.

Link:
http://icvts.oxfordjournals.org/content/early/2014/02/19/icvts.ivu020.long

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Find more studies on cardiovascular diseases, antioxidants, NAC, PUFA, vitamin C and p-value of 0.05/95% CI right here. 

Objectives:
Different adiposity measures have been associated with increased risk of atrial fibrillation, however, results have previously only been summarized for BMI. Therefore, this review article (meta-analysis) has been conducted.

Is there an association between different adiposity measures and risk of atrial fibrillation?

Study design:
This review article included 25 prospective studies with 83,006 cases among 2,405,381 participants.

Results and conclusions:
The investigators found every 5 unit increment in BMI significantly increased risk of atrial fibrillation with 28% [RR= 1.28, 95% CI = 1.20-1.38, I2 = 97%].

The investigators found every 10 cm increase in waist circumference significantly increased risk of atrial fibrillation with 18% [95% CI = 1.12-1.25, I2 = 73%, n = 5].

The investigators found every 10 cm increase in hip circumference significantly increased risk of atrial fibrillation with 32% [95% CI = 1.16-1.51, I2 = 91%, n = 3].

The investigators found every 0.1 unit increase in waist-to-hip ratio significantly increased risk of atrial fibrillation with 9% [95% CI = 1.02-1.16, I2 = 44%, n = 4].

The investigators found every 5 kg increase in fat mass significantly increased risk of atrial fibrillation with 9% [95% CI = 1.02-1.16, I2 = 94%, n = 4].

The investigators found every 10% increase in fat percentage nonsignificantly increased risk of atrial fibrillation with 10% [95% CI = 0.92-1.33, I2 = 90%, n = 3]. Nonsignificantly because RR of 1 can be found in the 95% CI of 0.92 to 1.33. RR of 1 means no risk.

The investigators found every 5 kg increase in weight significantly increased risk of atrial fibrillation with 10% [95% CI = 1.08-1.13, I2 = 74%, n = 10].

The investigators found every 5% increase in weight gain nonsignificantly increased risk of atrial fibrillation with 8% [95% CI = 0.97-1.19, I2 = 86%, n = 2]. Nonsignificantly means, there is no association at a 95% confidence.

The investigators found the association between BMI and atrial fibrillation was nonlinear [p nonlinearity 0.0001] with a stronger association at higher BMI levels. However, increased risk was observed even at a BMI of 22-24 compared to 20.

The investigators concluded general and abdominal adiposity and higher body fat mass increase risk of atrial fibrillation.

Original title:
Body mass index, abdominal fatness, fat mass and the risk of atrial fibrillation: a systematic review and dose-response meta-analysis of prospective studies by Aune D, Sen A, […], Vatten LJ.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28194602

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Find here more information/studies about cardiovascular diseases and overweight.

Objectives:
Do consuming tomato products and lycopene supplementation reduce cardiovascular risk among adult subjects >18 years of age?

Study design:
This review article included 21 studies.

Results and conclusions:
The investigators found consuming tomato was associated with a significant reduction of 0.22 mmol/L in LDL-cholesterol [p = 0.006]. Significant means, there is an association at a 95% confidence.

The investigators found consuming tomato was associated with a significant reduction of 0.25 in plasma IL-6 concentration [p = 0.03].

The investigators found consuming tomato was associated with a significant improvement of 2.53% in flow-mediated dilation (FMD) [p = 0.01].

The investigators found lycopene supplementation reduced systolic blood pressure with 5.66 mmHg [p = 0.002].

The investigators found no other outcome was significantly affected by these interventions.

The investigators concluded consuming tomato products and lycopene supplementation had positive effects on blood lipids, blood pressure and endothelial function. These results support the development of promising individualised nutritional strategies involving tomatoes to tackle cardiovascular diseases.

Original title:
Tomato and lycopene supplementation and cardiovascular risk factors: A systematic review and meta-analysis by Cheng HM, Koutsidis G, […], Lara J.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28129549

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Find here more information/studies about vegetable consumption, carotenoids and cardiovascular diseases.

Impaired endothelial function is an early indicator of atherosclerosis. Endothelial function is often quantified by flow-mediated dilation (FMD), which represents the endothelium-dependent relaxation of a conduit artery-typically the brachial artery - due to an increased blood flow. Flow-mediated dilation (FMD) is endothelium-dependent and can be assessed by ultrasound in the brachial artery.