More fiber may lower risk for heart disease

Each additional 7 g of total fiber consumed per day may lower risk for CHD and CVD by 9%.

This finding comes from a systematic review and meta-analysis of 22 prospective studies that reported associations between fiber intake and CHD or CVD. The studies were published from January 1990 to August 2013, and each had a minimum follow-up of 3 years.

Total dietary fiber intake was associated with reduced risk for CVD (RR per 7 g/day increase=0.91; 95% CI, 0.88-0.94) and CHD (RR per 7 g/day increase=0.91; 95% CI, 0.87-0.94).

The strength of the association depended on the source or type of the fiber, the researchers reported.

Intake of insoluble fibers, fiber from cereal sources, and fiber from vegetable sources were associated with lower risk for CHD and CVD. Intake of fiber from fruit sources was associated with lower risk for CVD, but not for CHD. Intake of soluble fibers was not associated with lower risk for CHD or CVD, although there was a nonsignificant reduction, according to the study.

There were not enough data to draw conclusions about other sources of fiber, the researchers wrote. “Our findings relate only to fiber from food intake rather than from fiber isolates or extracts, and any public health messages must therefore reflect this.”

To achieve a 9% risk reduction for CHD and CVD by consuming an additional 7 g of fiber per day, healthy adults can consume one portion of whole grains plus a portion of beans or lentils, or eat two to four servings of fruit and vegetables, the researchers wrote.

In a related editorial, Robert B. Baron, MD, MS, of the University of California, San Francisco, said “clinicians should enthusiastically and skillfully recommend that patients consume more dietary fiber.” Besides the present findings on fiber and CHD and CVD, there is research showing that increased dietary fiber is associated with reduction in lipids and blood sugar, less constipation and diverticular disease, and increased satiety. There also may be benefits in terms of all-cause mortality, he wrote.

A challenge, according to Baron, is that food labeling often does not make it easy to identify which foods are whole grains. He recommended looking for foods with whole grain listed as the first ingredient or calculating the ratio of grams of carbohydrates to grams of dietary fiber. Breads with a ratio of less than 10:1 and cereals with a ratio of around 5:1 are consistent with a higher-fiber product, he wrote.

For more information:

Baron RB. BMJ. 2013;doi:10.1136/bmj.f7401.

Threapleton DE. BMJ. 2013;doi:10.1136/bmj.f6879.

Disclosure: One researcher received sponsorship from Kellogg Marketing and Sales Co. (UK). The other researchers and Baron report no relevant financial disclosures.