Whole-grain and a high-fiber diet intake are routinely recommended for the prevention of many diseases, there are however few comprehensive and quantitative assessments of available data how this diet affects humans.

This has however changed with this study “Greater Whole-Grain Intake Is Associated with Lower Risk of Type 2 Diabetes” published in the The Journal of Nutrition and done at the University of California, Los Angeles.

The aim of the study was to systematically examine longitudinal studies investigating whole-grain and fiber intake in relation to the risk of type 2 diabetes (T2D), cardiovascular disease (CVD), weight gain, and metabolic risk factors.

The study researchers noted that an increase in dietary whole grain is directly linked to a decrease in diabetes, cardiovascular disease, and overall weight gain. Reducing the risk of diabetes by about 26% and vascular disease with approximately 21%.

“Whole-grain and high-fiber intake are routinely recommended for prevention of vascular diseases; however, there are no comprehensive and quantitative assessments of available data in humans. The aim of this study was to systematically examine longitudinal studies investigating whole-grain and fiber intake in relation to risk of type 2 diabetes (T2D), cardiovascular disease (CVD), weight gain, and metabolic risk factors. We identified 45 prospective cohort studies and 21 randomized controlled trials (RCT) between 1966 and February 2012 by searching the Cumulative Index to Nursing and Allied Health Literature, Cochrane, Elsevier Medical Database, and PubMed. Study characteristics, whole-grain and dietary fiber intakes, and risk estimates were extracted using a standardized protocol. Using random effects models, we found that compared with never/rare consumers of whole grains, those consuming 48–80 g whole grain/d (3–5 serving/d) had an ~26% lower risk of T2D [RR = 0.74 (95% CI: 0.69, 0.80)], ~21% lower risk of CVD [RR = 0.79 (95% CI: 0.74, 0.85)], and consistently less weight gain during 8–13 y (1.27 vs 1.64 kg; P = 0.001). Among RCT, weighted mean differences in post-intervention circulating concentrations of fasting glucose, total and LDL-cholesterol comparing whole-grain intervention groups with controls indicated significantly lower concentrations after whole-grain interventions [differences in fasting glucose: −0.93 mmol/L (95% CI: −1.65, −0.21), total cholesterol: −0.83 mmol/L (−1.24, −0.42); and LDL-cholesterol: −0.72 mmol/L (−1.34, −0.11)]. Findings from this meta-analysis provide evidence to support beneficial effects of whole-grain intake on vascular disease prevention. Potential mechanisms responsible for whole grains’ effects on metabolic intermediates require further investigation in large intervention trials.”

________________________________
Greater Whole-Grain Intake Is Associated with Lower Risk of Type 2 Diabetes, Cardiovascular Disease, and Weight Gain. J. Nutr. May 30, 2012.
________________