Front-Page News Flashes on Fiber

Dietary fiber made front-page news flashes again during the past couple of months, raising the question: “Is it really worth the effort it takes to chomp down that oatmeal, celery, or Fiber-One?”  In December, the FDA[1] confirmed its conviction that soluble fiber is beneficial in preventing cardiovascular disease (CVD), issuing a final ruling authorizing barley products to carry a health claim on the relationship between soluble fiber and reduced risk of coronary heart disease (CHD). Evidence from five clinical trials demonstrated that consuming whole grain barley and dry milled barley products – such as barley bran, flakes, flour, and pearled barley, providing at least 3 g beta-glucan fiber per day – effectively lowered serum total and LDL-cholesterol levels, which in turn may reduce the risk of CHD. Therefore, in addition to certain oat products, whole grain barley and certain dry milled barley grain products are appropriate sources of beta-glucan soluble fiber for the health claim. In the December issue of the American Journal of Clinical Nutrition, D. Lairon and coworkers[2] reported that the insoluble fiber from cereals also reduces risk factors of CVD, including being overweight and having a high body mass index. These findings suggest that it is time to “fiber-up” if your concern is CHD.

However, if it is colon cancer, the news was not so convincing. A meta-analysis of 13 prospective colon cancer studies by Yikyung Park and colleagues[3]  – involving over 725 thousand participants and reported in the Journal of the American Medical Association –

found that although dietary fiber intake was inversely associated with risk of colorectal cancer in age-adjusted analyses, the association between dietary fiber and risk of colon cancer was no longer significant, after accounting for other dietary risk factors. So if you need a p<0.05 to make you eat fiber to prevent colon cancer, you are off the hook for now. But overall, adding both soluble and insoluble fiber to your diet still would be a smart resolution for good health in 2006.

References

[1] http://www.cfsan.fda.gov/~lrd/fr051223.html

[1] Lairon et al., Am. J. Clin. Nutr. 2005. 82:1185-94.

[1] Park et al., JAMA 2005. 294:2849-57.