Nutrition and health

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

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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

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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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Lycopene is a carotenoid and is responsible for the yellow colour in tomatoes. Carotenoids are antioxidants.

Objectives:
Is supplementation of formula milk with LCPUFA (long-chain polyunsaturated fatty acids) both safe and beneficial for full-term infants, while focusing on effects on visual function, neurodevelopment and physical growth?

Study design:
This review article included 15 RCTs (n = 1889).
9 studies assessed visual acuity, 6 of which used visual evoked potentials (VEP), 2 Teller cards and 1 both. 4 studies reported beneficial effects and the remaining 5 did not.
GRADE analysis of the outcomes indicated that the overall quality of evidence was low.

Results and conclusions:
The investigators found a meta-analysis of 3 RCTs (n = 244) showed significant benefit for sweep VEP acuity at 12 months (log of the minimum angle of resolution) [MD = -0.15, 95% CI = -0.17 to -0.13, I2 = 0%, low-quality of evidence].
However, the meta-analysis of 3 other RCTs (n = 256) showed no benefit for visual acuity measured with Teller cards at 12 months (cycles/degree) [MD = -0.01, 95% CI = -0.12 to 0.11, I2 = 0%, low-quality of evidence].

The investigators found meta-analysis of 4 RCTs (n = 661) revealed no significant differences between LCPUFA and placebo groups in BSID Mental Developmental Index scores at 18 months [MD = 0.06, 95% CI = -2.01 to 2.14, I2 = 75%, low-quality of evidence] and no significant differences in BSID Psychomotor Development Index scores at 18 months [MD = 0.69, 95% CI = -0.78 to 2.16, I2 = 61%, low-quality of evidence].

There were also no significant differences between the two groups in BSID-II scores at one year and two years of age.

The investigators found meta-analysis of 5 RCTs (n = 521) showed that the supplemented group had lower weight (z scores) at one year of age [MD = -0.23, 95% CI = -0.40 to -0.06, I2 = 83%, low-quality of evidence] and that the two groups showed no significant differences with respect to length and head circumference (z scores).

The investigators found meta-analysis at 18 months and at two years revealed no significant differences between the two groups with respect to weight (kg), length (cm) and head circumference (cm).

The investigators concluded there are no beneficial effects or harms of LCPUFA supplementation on neurodevelopmental outcomes of formula-fed full-term infants and no consistent beneficial effects on visual acuity. Therefore, routine supplementation of full-term infant milk formula with LCPUFA cannot be recommended at this time.

Original title:
Long chain polyunsaturated fatty acid supplementation in infants born at term by Jasani B, Simmer K, […], Rao SC.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28281303

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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

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Objectives:
Is a low maternal circulating 25 hydroxyvitamin D (25-OHD) associated with an increased risk of preterm birth or spontaneous preterm birth and can vitamin D supplementation alone during pregnancy reduce risk of preterm birth?

Study design:
This review article included 6 RCTs and 18 observational studies.

Results and conclusions:
The investigators found maternal circulating 25-OHD deficiency significantly increased risk of preterm birth with 25% [pooled OR = 1.25, 95% CI = 1.13-1.38]. However, maternal circulating 25-OHD insufficiency was not associated with an increased risk of preterm birth [pooled OR = 1.09, 95% CI = 0.89-1.35]. Not associated because OR of 1 was found in 95% CI of 0.89 to 1.35. OR of 1 means no risk/association.

The investigators found vitamin D supplementation alone during pregnancy significantly reduced risk of preterm birth with 43% [pooled RR = 0.57, 95% CI = 0.36-0.91]. Significantly because RR of 1 was not found in 95% CI of 0.36 to 0.91. RR of 1 means no risk/association.

The investigators found maternal circulating 25-OHD 50 nmol/L significantly increased risk of spontaneous preterm birth with 45% [pooled OR = 1.45, 95% CI = 1.20-1.75]. 

The investigators concluded a maternal circulating 25-OHD 50 nmol/L increases risk of spontaneous preterm birth and vitamin D supplementation alone during pregnancy reduces risk of preterm birth. However, extrapolation of the results must be done with caution and there is urgent need for larger, better-designed RCT to confirm this effect.

Original title:
Vitamin D and risk of preterm birth: Up-to-date meta-analysis of randomized controlled trials and observational studies by Zhou SS, Tao YH, […], Tao FB.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28150405

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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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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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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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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.