Nutrition and health

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:
Prostate cancer (PCa) now remains the 2nd most frequently diagnosed cancer. In recent years, chemoprevention for prostate cancer becomes a possible concept. Especially, many phytochemicals rich foods are suggested to lower the risk of cancer. Among these foods, green tea is considered as effective prevention for various cancers. However, clinical trials and previous meta-analyses on the relationship between green tea consumption and the risk of prostate cancer have produced inconsistent outcomes. Therefore, this review article (meta-analysis) has been conducted.

Does green tea intake reduce prostate cancer risk?

Study design:
This review article included 4 cohort studies, 3 case-control studies and 3 RCTs. The cohort studies and case-control studies which investigated the association between green tea intake and prostate cancer risk included 1435 cases among 96,332 individuals and the 3 RCTs studied the relationship between EGCG and prostate cancer incidence included 87 volunteers in EGCG arms of 179 individuals.

No publication bias was found.

Results and conclusions:
The investigators found in observational studies (4 cohort studies and 3 case-control studies) for the highest versus lowest category of green tea intake a non-significant reduced prostate cancer risk of 8% [RR = 0.92, 95% CI = 0.77-1.11, I2 = 0%, p = 0.46] for all studies;

a non-significant reduced prostate cancer risk of 2.3% [RR = 0.977, 95% CI = 0.80-1.19] for cohort studies and;
a non-significant reduced prostate cancer risk of 27.7% [RR = 0.623, 95% CI = 0,368-1.056, I2  = 0%, p =  0.46] for case-control studies.

The investigators found no association between 1-5 cups of green tea per day and prostate cancer risk.

However, the investigators found 7 cups of green tea per day significantly reduced prostate cancer risk with 19% [RR = 0.81, 95% CI = 0.67-0.97]. The significant reduced prostate cancer risk increased to 26% [RR = 0.74, 95% CI = 0.59-0.93] for 9 cups and to 44% [RR = 0.56, 95% CI = 0.35-0.92) for 15 cups.

The investigators found in 3 RCTs when compared to placebo green tea catechins significantly reduced prostate cancer risk  with 62% [RR = 0.38, 95% CI = 0.16-0.86, p  =  0.02].

The investigators concluded that at least 7 cups/day green tea intake reduces prostate cancer. This is further confirmed by the potential protective effect of green tea catechins on prostate cancer. Further prospective study with accurate measurement of green tea intake is required to substantiate these conclusions.

Original title:
Green tea and the risk of prostate cancer: A systematic review and meta-analysis by Guo Y, Zhi F, […], Zhang X.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5380255/

Additional information of El Mondo:
Find more information/studies on green tea consumption and cancer 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:
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 association between meat consumption and the risk of hepatocellular carcinoma (HCC) is still inconclusive. Therefore, this review article has been conducted.

Does meat consumption increase risk of hepatocellular carcinoma?

Study design:
This review article included 7 cohort studies and 10 case-control studies.

Results and conclusions:
The investigators found for the highest vs. lowest consumption levels a non-significant increased risk for hepatocellular carcinoma of 10% [RR = 1.10, 95% CI = 0.85-1.42] for red meat, a non-significant increased risk of 1% [RR = 1.01, 95% CI = 0.79-1.28] for processed meat and a non-significant decreased risk of 3% [RR = 0.97, 95% CI = 0.85-1.11] for total meat. Non-significant means, there is no association with a 95% confidence.

The investigators found for the highest vs. lowest consumption levels a significant decreased risk for hepatocellular carcinoma of 31% [RR = 0.69, 95% CI = 0.58-0.81] for white meat and a significant decreased risk of 22% [RR = 0.78, 95% CI = 0.67-0.90] for fish. The results remained quite stable after stratification by the confounding factors.
Significant means, there is an association with a 95% confidence.

The investigators concluded a high level of white meat or fish consumption reduces the risk of hepatocellular carcinoma, while intake of red meat, processed meat or total meat is not associated with hepatocellular carcinoma risk. These results suggest that dietary intervention may be a promising approach for prevention of hepatocellular carcinoma, which still need to be confirmed by further well-designed prospective studies and experimental research.

Original title:
Systematic review with meta-analysis: meat consumption and the risk of hepatocellular carcinoma by Luo J, Yang Y, [...], Zhu Y.

Link:
http://www.ncbi.nlm.nih.gov/pubmed/24588342

Additional information of El Mondo:
Find more studies/information on fish consumption, meat consumption and cancer right here.

A review article of cohort studies or case-control studies will answer the following question:
"Should I change my diet?".

Objectives:
Is there an association between meat intake and risk of esophageal cancer?

Study design:
This review article included 7 cohort studies and 28 case-control studies.

Results and conclusions:
The investigators found for the highest versus lowest total meat consumption categories a non-significant increased risk of 19% [95% CI = 0.98-1.46] for esophageal cancer.

The investigators found for the highest versus lowest red meat consumption categories a significant increased risk of 55% [95% CI = 1.22-1.96] for esophageal cancer.

The investigators found for the highest versus lowest processed meat consumption categories a significant increased risk of 33% [95% CI = 1.04-1.69] for esophageal cancer.

The investigators found for the highest versus lowest white meat consumption categories a significant decreased risk of 28% [95% CI = 0.60-0.86] for esophageal cancer.

The investigators found for the highest versus lowest poultry consumption categories a significant decreased risk of 17% [95% CI = 0.72-0.96] for esophageal cancer.

The investigators found for the highest versus lowest fish consumption categories a non-significant decreased risk of 5% [95% CI = 0.76-1.19] for esophageal cancer.

The investigators found when stratified by histological subtype, positive associations among esophageal squamous cell carcinoma and red meat, white meat and poultry and esophageal adenocarcinoma with total meat and processed meat.

The investigators concluded red meat and processed meat consumption increase risk of esophageal cancer, while white meat and poultry decrease risk of esophageal cancer. Fish consumption is not associated with incidence of esophageal cancer.

Original title:
Meat consumption is associated with esophageal cancer risk in a meat- and cancer-histological-type dependent manner by Zhu HC, Yang X, […], Sun XC.

Link:
http://www.ncbi.nlm.nih.gov/pubmed/24395380

Additional information of El Mondo:
Find more studies/information on meat consumption and cancer right here.
 

Objectives:
Epidemiological studies assessing the relationship between dietary vitamin B2 and the risk of breast cancer have produced inconsistent results. Therefore, this review article (meta-analysis) has been conducted.

Does dietary vitamin B2 intake reduce breast cancer risk?

Study design:
This review article included 10 epidemiologic studies (cohort or patient-controle studies) comprising totally 12,268 breast cancer patients.

No publication bias was found.

Results and conclusions:
The investigators found comparing the highest to the lowest dietary vitamin B2 intake a significant reduced risk of 15% for breast cancer [pooled relative risk = 0.85, 95% CI = 0.76-0.95, I2 = 40.7%].

The investigators found dose-response analysis showed that an increment of 1 mg/day dietary vitamin B2 intake significantly reduced risk of breast cancer with 6% [relative risk = 0.94, 95% CI = 0.90-0.99].

The investigators concluded that dietary vitamin B2 intake, at least 1 mg/day, is related to the reduced risk of breast cancer. However, additional research is also necessary to further explore this association.

Original title:
Dietary vitamin B2 intake and breast cancer risk: a systematic review and meta-analysis by Yu L, Tan Y and Zhu L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28035488

Additional information of El Mondo:
Find more information/studies on vitamin B2 and breast cancer 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.

Objectives:
Is there an association of intake of different vitamins and multiple-vitamin supplements and the incidence of colorectal cancer?

Study design:
This review article included 47 articles (cohort studies).

There was unacceptable heterogeneity for studies of multiple-vitamin supplements, so findings were inconclusive.

Results and conclusions:
The investigators found a significant reduced risk of 12% [multivariable-adjusted RR = 0.88, 95% CI = 0.81-0.95] for colorectal cancer when comparing the highest versus lowest dietary vitamin B9 (folate) intake. Significant means that there is an association with a 95% confidence.

The investigators found a significant reduced risk of 13% [multivariable-adjusted RR = 0.87, 95% CI = 0.77-0.99] for colorectal cancer when comparing the highest versus lowest dietary vitamin D intake. Significant because RR of 1 was not found in the 95% CI of 0.77 to 0.99. RR of 1 means no risk/association.

The investigators found a significant reduced risk of 12% [multivariable-adjusted RR = 0.88, 95% CI = 0.79-0.99] for colorectal cancer when comparing the highest versus lowest dietary vitamin B6 intake.

The investigators found a significant reduced risk of 14% [multivariable-adjusted RR = 0.86, 95% CI = 0.76-0.97] for colorectal cancer when comparing the highest versus lowest dietary vitamin B2 intake.

The investigators found, however, no association between both dietary vitamine A, C, E, B3 and B12 and the risk of colorectal cancer.

The investigators concluded high dietary vitamin B9 (folate), D, B6 and B2 intake reduces risk of colorectal cancer, but further study is needed.

Original title:
Vitamin and multiple-vitamin supplement intake and incidence of colorectal cancer: a meta-analysis of cohort studies by Liu Y, Yu Q, […], Li K.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/25491145

Additional information of El Mondo:
Find more studies/information on vitamines and colorectal cancer right here.

Objectives:
Red meat intake has been associated with risk of colorectal cancer, potentially mediated through heterocyclic amines. The metabolic efficiency of N-acetyltransferase 2 (NAT2) required for the metabolic activation of such amines is influenced by genetic variation. The interaction between red meat intake, NAT2 genotype and colorectal cancer has been inconsistently reported. Therefore, this review article has been conducted.

Is there an interaction between red meat intake, NAT2 genotype and colorectal cancer?

Study design:
This review article included 11 retrospective case-control studies with 8,290 colorectal cancer cases and 9,115 controls (subjects without colorectal cancer).

Results and conclusions:
The investigators found the highest quartile of red meat intake was associated with a 41% increased risk of colorectal cancer compared with the lowest quartile [OR = 1.41, 95% CI = 1.29-1.55].
However, a significant association was observed only for studies with retrospective diet data, not for studies with diet prospectively assessed before cancer diagnosis.

The investigators found when combining all studies, high red meat intake was similarly associated with colorectal cancer in those with a rapid/intermediate NAT2 genotype [OR = 1.38, 95% CI = 1.20-1.59] as with a slow genotype [OR = 1.43, 95% CI = 1.28-1.61, p interaction = 0.9].

The investigators concluded high red meat intake was associated with increased risk of colorectal cancer only from retrospective case-control studies and not modified by NAT2 enzyme activity.

Original title:
Red Meat Intake, NAT2, and Risk of Colorectal Cancer: A Pooled Analysis of 11 Studies by Ananthakrishnan AN, Du M, […], Chan AT.

Link:
http://cebp.aacrjournals.org/content/cebp/24/1/198.full.pdf

Additional information of El Mondo:
Find more studies/information on red meat consumption and colorectal cancer right here.

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

Additional information of El Mondo:
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Lycopene is a carotenoid and is responsible for the yellow colour in tomatoes. Carotenoids are antioxidants.

Objectives:
The association between dietary carbohydrate intake and colorectal cancer risk remains controversial. Therefore, this review article (meta-analysis) has been conducted.

Does higher dietary carbohydrate intake increase colorectal cancer risk?

Study design:
This review article included 8 case-controle studies en 9 prospective cohort studies involving 14,402 colorectal cancer patients among 846004 participants; 17 studies with 9,235 cases were to assess the association on colon cancer and 13  studies with 3,272 cases were to  assess the association on rectum cancer. 

No publication bias was found.

Results and conclusions:
The investigators found no association between dietary carbohydrate intake and colorectal cancer risk [pooled RR = 1.08, 95% CI = 0.93-1.23, I2 = 68.3%, p-heterogeneity 0.001]. No association because RR of 1 was found in the 95% CI of 0.93 to 1.23. RR of 1 means no risk/association.

The investigators found no association between dietary carbohydrate intake and colon cancer risk [pooled RR = 1.09, 95% CI = 0.95-1.25, I2 = 48.3%].

The investigators found no association between dietary carbohydrate intake and rectum cancer risk [pooled RR = 1.17, 95% CI = 0.98-1.39, I2 = 17.8%].

The investigators found in subgroup analyses for study design, a non-significant association for both case-control studies [summary RR = 1.40, 95% CI = 0.93-2.09] and cohort studies [summary RR = 0.99, 95% CI = 0.85-1.15].  

The investigators found in stratified analysis by geographic locations, higher dietary   carbohydrate intake had no significant association on colorectal cancer risk among American populations [summary RR = 1.08, 95% CI = 0.89-1.30], European populations [summary RR = 1.23, 95% CI = 0.91-1.64] or Asian population [summary RR = 0.98, 95% CI = 0.65-1.46].

The investigators found higher dietary carbohydrate intake significantly increased risk of colorectal cancer with 23% in men populations [summary RR = 1.23, 95% CI = 1.01-1.57], but not in women populations.

The investigators concluded that higher dietary carbohydrate intake increases colorectal cancer risk in men populations. Further studies are wanted to confirm this relationship.

Original title:
A meta-analysis between dietary carbohydrate intake and colorectal cancer risk: Evidence from 17 observational studies by Huang J, Pan G, [...], Zhu Z.

Link:
http://www.bioscirep.org/content/ppbioscirep/early/2017/03/15/BSR20160553.full.pdf

Additional information of El Mondo:
Find more information/studies on carbohydrates and colorectal cancer right here.
 

Objectives:
Previous observational studies regarding the existence of an association between folate intake and the risk of breast cancer have been inconsistent. Therefore, this review article has been conducted.

Does a higher dietary folate intake reduce breast cancer risk?

Study design:
This review article included 14 prospective cohort studies that reported data on 677,858 individuals.
The participant follow-up period ranged 4.7-17.4 years and the number of individuals per study ranged 11,699-88,818.
There was no publication bias.

Results and conclusions:
The investigators found no association between dietary folate intake and breast cancer risk for highest versus lowest category  [RR =  0.97, 95% CI = 0.90-1.05, p  = 0.451, I2 =  57.5%, p = 0.004].

The investigators found dose-response meta-analysis findings showed no association between the risk of breast cancer and a 100 µg/day increase in dietary folate intake [RR = 0.99, 95% CI = 0.98-1.01, p = 0.361, I2 = 66.2%, p 0.001].

The investigators found evidence of a nonlinear relationship between dietary folate intake and the risk of breast cancer.

A daily dietary folate intake of 200-320 µg was associated with a reduced risk of breast cancer. However, daily folate intake levels >400 µg was associated with a increased risk of breast cancer.

The investigators found overall folate intake level was associated with a reduced breast cancer risk of 36% if the patients had a daily alcohol intake >10 g [RR for highest versus lowest category = 0.64, 95% CI = 0.43-0.97].

The investigators concluded there are no effects of increased dietary folate intake on the incidence of breast cancer. But, a daily dietary folate intake of 200-320 µg was associated with a reduced risk of breast cancer. However, daily folate intake levels >400 µg was associated with a increased risk of breast cancer. Future studies should focus on specific populations in order to analyze primary breast cancer prevention.

Original title:
Folate Intake and the Risk of Breast Cancer: A Dose-Response Meta-Analysis of Prospective Studies by Zhang YF, Shi WW, […], Zhou YH.

Link:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4059748/

Additional information of El Mondo:
Find more studies/information on folate intake and breast cancer right here.
 

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

Additional information of El Mondo:
Find more information/studies on GL and GI diet right here.

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:
There is no published systematic review and meta-analysis regarding the effect of olive oil consumption on cancer occurrence. Therefore, this review article has been conducted.

Does olive oil consumption reduce cancer risk?

Study design:
This review article included 19 case-control studies (13800 cancer patients and 23340 controls).

Random effects meta-analysis was applied in order to evaluate the research hypothesis.
Heterogeneity of the effect-size measures was observed in studies performed in the Mediterranean region (n = 15, p = 0.0002), whereas no heterogeneity was observed in non-Mediterranean studies (n = 4, p = 0.12).

Results and conclusions:
The investigators found when comparing with the lowest, the highest category of olive oil consumption was significantly associated with lower odds of having any type of cancer [log odds ratio = -0.41, 95% CI = -0.53 to -0.29, Cohran's Q = 47.52, p = 0.0002, I2 = 62%].

The investigators found both Mediterranean and non-Mediterranean people reported olive oil intake were less likely to have developed any type of cancer.

The investigators found olive oil consumption was significantly associated with lower odds of developing breast cancer [logOR = -0.4,  95% CI = -0.78 to -0.12] and a cancer of the digestive system [logOR = -0.36, 95% CI = -0.50 to -0.21] compared with the lowest intake.

The investigators concluded olive oil consumption probably reduces risk of any type of cancer, especially breast cancer and cancer of the digestive system. Probably, because this review article only included case-control studies and there was heterogeneity.
The reduced risk is similar to studies performed in Mediterranean as well as non-Mediterranean countries. However, it is still unclear whether olive oil's monounsaturated fatty acid content or its antioxidant components are responsible for its beneficial effects.

Original title:
Olive oil intake is inversely related to cancer prevalence: a systematic review and a meta-analysis of 13800 patients and 23340 controls in 19 observational studies by Psaltopoulou T, Kosti RI, […], Panagiotakos DB.

Link:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3199852/

Additional information of El Mondo:
Find more studies on olive oil consumption and fat.

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

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

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

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

Objectives:
Many studies suggest that high-fat diets are linked to the etiology of non-Hodgkin's lymphoma (NHL). However, the findings are inconsistent and therefore the association between fat and non-Hodgkin's lymphoma remains unclear. Therefore, this review article (meta-analysis) has been conducted.

Does a high fat dietary intake increase non-Hodgkin's lymphoma risk?

Study design:
This review article included two cohort studies and eight case-control studies.

The funnel plot revealed no evidence for publication bias.

Results and conclusions:
The investigators found a significant higher risk of 26% for non-Hodgkin's lymphoma for total fat consumption [RR = 1.26, 95% CI = 1.12-1.42]. Significant because RR of 1 was not found in the 95% CI of 1.12 to 1.42. RR of 1 means no risk/association.

The investigators found subgroup analysis showed a significant higher risk of 41% for diffuse large B-cell lymphoma for total fat consumption [RR = 1.41, 95% CI = 1.08-1.84]. However, there was no significant association between total fat consumption and increase risk of follicular lymphoma [RR = 1.21, 95% CI = 0.97-1.52], small lymphocytic lymphoma/chronic lymphocytic leukemia [RR = 0.91, 95% CI = 0.68-1.23] nor with T cell lymphoma [RR = 1.12, 95% CI = 0.60-2.09].
No significant because RR of 1 was found in the 95% CI of 0.60 to 2.09. RR of 1 means no risk/association.

The investigators concluded that total fat consumption increases non-Hodgkin's lymphoma; especially diffuse large B-cell lymphoma.

Original title:
Dietary Fat Consumption and Non-Hodgkin's Lymphoma Risk: A Meta-analysis by Han TJ, Li JS, [...], Xu HZ.

Link:

https://www.ncbi.nlm.nih.gov/pubmed/28094569

Additional information of El Mondo:
Find more information/studies on fat and cancer right here.

Lymphoma is the most common blood cancer. The two main forms of lymphoma are Hodgkin lymphoma and non-Hodgkin lymphoma (NHL). The human body has two main types of lymphocytes that can develop into lymphomas:

1. B lymphocytes (B cells) and;
2. T lymphocytes (T cells).

B-cell lymphomas are much more common than T-cell lymphomas and account for approximately 85 percent of all non-Hodgkin lymphomas. Diffuse large B cell lymphomas (DLBCLs) are the commonest subtype of non-Hodgkin's lymphoma. They constitute about 30 to 40% of adult non-Hodgkin's lymphoma.

A high total fat consumption corresponds to a diet with >35 En% fat and/or >10 En% saturated fat. A diet with >35 En% fat is a diet with a lot of products/meals providing >35 En% fat.
 

Objectives:
Several epidemiological studies investigating the association between dietary vitamin E intake and the risk of lung cancer have demonstrated inconsistent results. Therefore, this review article (meta-analysis) has been conducted.

Does dietary vitamin E intake reduce lung cancer risk?

Study design:
This review article included 9 cohort studies with 4,164 lung cancer cases among 435,532 participants.

The Egger’s test showed no evidence of publication bias [t = 1.24, p = 0.246].

Results and conclusions:
The investigators found for the highest versus lowest categories of dietary vitamin E intake a reduced risk of 16% for lung cancer [pooled RR = 0.84, 95% CI = 0.76-0.93, I2 = 41.1%].

The investigators found in subgroup analysis by geographic location a significant inverse association of dietary vitamin E intake with lung cancer for the European and American populations [pooled RR = 0.85, 95% CI = 0.75-0.95), but not for the Asian population. Significant means that there is an association with a 95% confidence.

The investigators found every 2 mg/d increase in dietary vitamin E intake statistically decreased the risk of lung cancer by 5% [RR = 0.95, 95% CI = 0.91-0.99, p linearity = 0.0237].

The investigators concluded that higher dietary vitamin E intake; at least 2 mg per day exerts a protective effect against lung cancer.

Original title:
Association of dietary vitamin E intake with risk of lung cancer: a dose-response meta-analysis by Zhu YJ, Bo YC, [...], Qiu CG.

Link:
http://apjcn.nhri.org.tw/server/APJCN/26/2/271.pdf

Additional information of El Mondo:
Find more information/studies on vitamin E and cancer right here.
 

Objectives:
Epidemiological studies suggest that soya consumption as a source of phyto-oestrogens and isoflavones may be associated with a reduced risk of colorectal cancer. However, findings have not yet been synthesised for all groups of phyto-oestrogens. Therefore, this review article (meta-analysis) has been conducted.

Does soya consumption reduce colorectal cancer risk?

Study design:
This review article included 16 studies (case-control studies and cohort studies).

Results and conclusions:
The investigators found in case-controle studies a significant reduced risk of 24% [pooled RR = 0.76, 95% CI = 0.69-0. 84] for colorectal cancer when comparing the highest phyto-oestrogens with the lowest intake category. However, the reduced risk for colorectal cancer was not significant in cohort studies [pooled RR = 0.95, 95% CI = 0.85-1.06].

The investigators found in case-controle studies a significant reduced risk of 23% [pooled RR = 0.77, 95% CI = 0.69-0. 85] for colorectal cancer when comparing the highest isoflavones with the lowest intake category. However, the reduced risk for colorectal cancer was not significant in cohort studies [pooled RR = 0.94, 95% CI = 0.84-1.05].

The investigators found in case-controle studies a significant reduced risk of 30% [pooled RR = 0.70, 95% CI = 0.56-0. 89] for colorectal cancer when comparing the highest lignans with the lowest intake category. However, the reduced risk for colorectal cancer was not significant in cohort studies [pooled RR = 1.00, 95% CI = 0.64-1.57].

The investigators found dose-response analysis yielded an 8% reduced risk of colorectal neoplasms for every 20 mg/d increase in isoflavones intake in Asians [pooled RR = 0.92, 95% CI = 0.86-0.97].

The investigators found dose-response analysis showed a non-linear inverse association with colorectal cancer risk for lignans intake, but no association for circulating enterolactone concentrations was observed.

The investigators concluded every 20 mg/d increase in isoflavones dietary intake reduces risk of colorectal neoplasms with 8% in Asians.

Original title:
Phyto-oestrogens and colorectal cancer risk: a systematic review and dose-response meta-analysis of observational studies by Jiang R, Botma A, […], Chang-Claude J.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28091359

Additional information of El Mondo:
Find more information/studies on isoflavones, colorectal cancer and cohort study/review article right here.

Objectives:
Some observational studies have shown that elevated serum selenium levels are associated with reduced prostate cancer risk. However, not all published studies support these results. Therefore, this review article (meta-analysis) has been conducted.

Does an elevated serum selenium level reduce prostate cancer risk?

Study design:
This review article included 12 case-control studies, 4 cohort studies and 1 RCT with 6,136 prostate cancer cases among 34,901 participants.

Results and conclusions:
The investigators found elevated serum selenium levels significantly decreased prostate cancer risk with 24% [pooled OR = 0.76, 95% CI = 0.64 to 0.91, I2  =  60.8%, p  =  0.001].  Significant means that there is an association with a 95% confidence.

The investigators found in subgroup analysis, an inverse association between elevated serum selenium levels and prostate cancer risk in case-control studies, current and former smokers, high-grade cancer cases, advanced cancer cases and different populations. However, such correlations were not found among cohort studies, nonsmokers, low-grade cancer cases and early stage cancer cases.

The investigators concluded that elevated serum selenium levels may decrease high-grade prostate cancer among current and former smokers. May decrease because the inverse relationship between elevated serum selenium levels and prostate cancer risk was not significant among cohort studies. Therefore, further cohort studies and randomized control trials based on non-Western populations are required.

Original title:
Serum selenium levels and prostate cancer risk: A MOOSE-compliant meta-analysis by Cui Z, Liu D, […], Liu G.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5293444/

Additional information of El Mondo:
Find more information/studies on selenium and cancer right here.