Whole-Grain Oats Lower Cholesterol

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April 18, 2007 (Middlesbrough, UK) – New data from a meta-analysis reviewing the effect of whole-grain foods or diets on coronary heart disease (CHD) has shown that whole-grain cereals can reduce CHD risk factors, with specific reductions in total- and LDL-cholesterol levels [1]. The studies, however, are small and of short duration, and, as a result, the effect of whole-grains on CHD deserves further study, say investigators.

"While there is growing evidence from observational studies that whole grains have benefits for coronary heart disease, there is insufficient evidence available from randomized controlled trials [RCTs] to make any conclusions about whole grains in general and coronary heart disease, except whole-grain oats," writes lead investigator Dr Sarah Kelly (University of Teesside, Middlesbrough, UK) in the analysis, published online April 18, 2007 in the Cochrane Database of Systematic Reviews. "There is some evidence from RCTs that whole-grain oats can lower LDL- and total-cholesterol levels in those with preexisting risk factors for CHD. This effect was seen at four weeks for total cholesterol so may be effective even with short interventions."

Further study is needed

Whole-grain and whole-meal cereal foods are grain foods that include the outer layers of the grain, including the bran and germ. Previously, there have been a few epidemiological studies that examined the association between the intake of whole-grain foods and risk of CHD, including the Iowa Women's Health Study and Nurses' Health Study, with both of these studies showing a benefit with whole-grain consumption.

The purpose of this review, write the authors, was to examine the current evidence from RCTs to assess the relationship between whole-grain-food consumption and the various effects on CHD mortality, morbidity, and CHD risk factors in subjects with coronary disease or those with risk factors for coronary disease.

In total, 10 studies were included in the meta-analysis, of which eight trials studied the effects of whole-grain oats. The trials were short-term, ranging from four to eight weeks in length, and included a small number of patients. Overall, 914 subjects were included in the meta-analysis. None of the studies identified reported the effect of whole grains on CHD mortality or CHD events. However, in seven of the eight studies using oats, significantly lower LDL- and total-cholesterol levels were reported in those randomized to the whole-grain arm. The absolute reduction in total and LDL cholesterol was roughly 7 mg/L.

"Despite the consistency of the effects in trials of whole-grain oats, the positive findings should be interpreted cautiously," conclude Kelly and colleagues. "Many of the trials identified were short-term, of poor quality, and had insufficient power. Most of the trials were funded by companies with commercial interests in whole grains. There is a need for well-designed, adequately powered, longer-term randomized controlled studies in this area. In particular, there is a need for randomized controlled trials on whole-grain foods and diets other than oats."

1. Kelly SAM, Summerbell CD, Brynes A. Whole-grain cereals for coronary heart disease. Cochrane Database Syst Rev 2007; DOI: 10.1002/14651858.CD005051.pub2. Available at: http://www.mrw.interscience.wiley.com/cochrane/clsysrev/articles/CD005051/frame.html.

Source: http://www.medscape.com/viewarticle/555398?src=mp