Can this diet save your life?

People who eat more fiber and whole grains have a significantly lower risk of mortality and non-communicable diseases—including coronary heart disease, stroke, type 2 diabetes, and colorectal cancer—compared with people who eat less fiber and whole grains, researchers reported in The Lancet.

They found that a high-fiber diet was associated with a 15% reduced risk of all-cause mortality, a 16% lower risk of type 2 diabetes and colorectal cancer, a 22% reduced risk of stroke, a 24% lower risk of coronary heart disease, and a 31% reduced risk of death from coronary heart disease.

“Our research indicates we should have at least 25-29 grams of fiber from foods per day, although most of us currently consume less than 20 grams of fiber per day,” said the study’s first author Andrew Reynolds, PhD, MSc, Department of Medicine, University of Otago, Dunedin, New Zealand.

And the more fiber and whole grains you eat, the greater benefit against mortality and chronic diseases. Dr. Reynolds and colleagues found that every extra 8 g of fiber consumed per day led to a risk reduction of 7% for all-cause mortality, 8% for colon cancer, 15% for type 2 diabetes, and 19% for coronary heart disease.

The researchers also determined that fiber’s effect on reduced risk is a direct one.

“The consistency between the trial and prospective study results, together with the dose-response relationships, provide support that the effect [of a high-fiber diet] on cardiometabolic diseases is likely to be causal and not a consequence of confounding variables,” they wrote.

It’s a ‘bran’ new day

With recent public health initiatives focused on consuming fewer carbohydrates—especially in the form of excess sugar—the importance of dietary fiber has been somewhat overlooked lately, Dr. Reynolds and coauthors observed.

“Although nutrition guidelines issued by many governments and professional organizations encourage increased consumption of vegetables, fruit, and whole grains, fewer quantitative guidelines for sources and intakes of dietary fiber and starch are available,” they wrote.

To that end, they performed a series of systematic reviews and meta-analyses that included 4,635 adult participants from 185 prospective studies and 58 clinical trials published in the last 40 years.

Not only did they find that a high-fiber diet was associated with reduced risk of mortality and non-communicable diseases, they also confirmed that eating more fiber reduced bodyweight and cholesterol levels. Consuming more whole grains had similar beneficial effects. However, low glycemic index or low glycemic-load diets were associated with only limited benefits.

“Considering current evidence, dietary glycemic index or glycemic load might be less useful as overall measures of carbohydrate quality than dietary fiber and whole grain content,” the authors wrote.

Dr. Reynolds advised: “Practical ways to increase fiber intake is to plan meals and snacks around whole grains, vegetables, pulses [eg, dry peas, beans, lentils, and chickpeas], and whole fruits.”

Funding for this study came from the Health Research Council of New Zealand, World Health Organization, Riddet Centre of Research Excellence, Healthier Lives National Science Challenge, University of Otago, and the Otago Southland Diabetes Research Trust.