Association of whole grain intake with all-cause, cardiovascular, and cancer mortality: a systematic review and dose–response meta-analysis from prospective cohort studies

Introduction: Whole grain intake has been associated with lower risks of multiple chronic conditions, but its association with mortality warrants further evaluation. Hypothesis: We performed a meta-analysis of prospective cohort studies on the association of whole grain intake with all-cause and cause-specific mortality, and tested the hypothesis that they followed inverse dose-response pattern. Methods: Published studies reporting relative risks (RRs) between whole grain consumption and mortality from Medline and Embase through August, 2015. Original results from National Health and Nutrition Examination Survey (NHANES) III and NHANES 1999-2004 were included. Whole grain ingredients (gram/day) were estimated among studies reporting RRs for ≥3 categories of whole grain intake. Results: Fourteen unique analyses were included, which consisted of 786,076 participants, 97,867 all-cause deaths, 23,957 CVD deaths, and 37,492 cancer deaths. Pooled RRs (95% confidence intervals) comparing high with low whole grain categories were 0.84 (0.80, 0.88; P <0.001, I2=74%, P heterogeneity<0.001) for all-cause mortality, 0.82 (0.79, 0.85; P <0.001, I2=0%, P heterogeneity=0.53) for CVD mortality, and 0.88(0.83, 0.94; P <0.001, I2=54%, P heterogeneity=0.02) for cancer mortality. Whole grain consumption was <50 grams/day among most studies. Dose-response meta-analysis showed strong monotonic associations between whole grain and mortality (All P nonlinearity > 0.05): RRs (95%CIs) for each 16 grams/day increase (approximately 1 serving/day) in whole grain were 0.93(0.92, 0.94) for all-cause mortality, 0.91(0.90, 0.93) for CVD mortality, and 0.95(0.94, 0.96) for cancer mortality. These findings were robust in several stratified analyses and/or sensitivity analyses. Egger’s test did not suggest significant publication bias. Conclusions: Our findings supported health benefit of increasing current whole grain intake of <1 serving/day to ≥3 servings/day as recommended by current Dietary Guidelines for Americans.

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Dietary intake and biomarkers of alpha linolenic acid and risk of all cause, cardiovascular, and cancer mortality: systematic review and dose-response meta-analysis of cohort studies

BMJ ◽

10.1136/bmj.n2213 ◽

2021 ◽

pp. n2213 ◽

Cited By ~ 1

Author(s):

Sina Naghshi ◽

Dagfinn Aune ◽

Joseph Beyene ◽

Sara Mobarak ◽

Masoomeh Asadi ◽

...

Keyword(s):

Systematic Review ◽

Cohort Studies ◽

Dose Response ◽

Cancer Mortality ◽

Prospective Cohort ◽

Lower Risk ◽

Meta Analysis ◽

Response Analysis ◽

Prospective Cohort Studies ◽

Risk Of Cancer

Abstract Objective To examine the associations between dietary intake and tissue biomarkers of alpha linolenic acid (ALA) and risk of mortality from all causes, cardiovascular disease (CVD), and cancer. Design Systematic review and meta-analysis of prospective cohort studies. Data sources PubMed, Scopus, ISI Web of Science, and Google Scholar to 30 April 2021. Study selection Prospective cohort studies that reported the risk estimates for death from all causes, CVD, and cancer. Data synthesis Summary relative risks and 95% confidence intervals were calculated for the highest versus lowest categories of ALA intake using random effects and fixed effects models. Linear and non-linear dose-response analyses were conducted to assess the dose-response associations between ALA intake and mortality. Results 41 articles from prospective cohort studies were included in this systematic review and meta-analysis, totalling 1 197 564 participants. During follow-up ranging from two to 32 years, 198 113 deaths from all causes, 62 773 from CVD, and 65 954 from cancer were recorded. High intake of ALA compared with low intake was significantly associated with a lower risk of deaths from all causes (pooled relative risk 0.90, 95% confidence interval 0.83 to 0.97, I 2 =77.8%, 15 studies), CVD (0.92, 0.86 to 0.99, I 2 =48.2%, n=16), and coronary heart disease (CHD) (0.89, 0.81 to 0.97, I 2 =5.6%, n=9), and a slightly higher risk of cancer mortality (1.06, 1.02 to 1.11, I 2 =3.8%, n=10). In the dose-response analysis, a 1 g/day increase in ALA intake (equivalent to one tablespoon of canola oil or 0.5 ounces of walnut) was associated with a 5% lower risk of all cause (0.95, 0.91 to 0.99, I 2 =76.2%, n=12) and CVD mortality (0.95, 0.91 to 0.98, I 2 =30.7%, n=14). The pooled relative risks for the highest compared with lowest tissue levels of ALA indicated a significant inverse association with all cause mortality (0.95, 0.90 to 0.99, I 2 =8.2%, n=26). Also, based on the dose-response analysis, each 1 standard deviation increment in blood concentrations of ALA was associated with a lower risk of CHD mortality (0.92, 0.86 to 0.98, I 2 =37.1%, n=14). Conclusions The findings show that dietary ALA intake is associated with a reduced risk of mortality from all causes, CVD, and CHD, and a slightly higher risk of cancer mortality, whereas higher blood levels of ALA are associated with a reduced risk of all cause and CHD mortality only. Systematic review registration PROSPERO CRD42021229487.

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