From The July 2001 Issue of Nutrition Science News

Cutting Fat No Heart Disease Relief

For years, the reduction of fat and cholesterol intake has been the foundation for the prevention of heart disease. To find if it is an effective preventive, researchers at University Dental Hospital of Manchester, UK, conducted a comprehensive review of all randomized, controlled intervention studies that showed reduced total fat, saturated fat, or cholesterol for six months. Researchers analyzed 27 studies, which included 1,430 deaths and 1,216 cardiovascular events, such as heart attack or stroke. No studies on trans fatty acids were found.

The meta-analysis showed that modifying fat intake caused a 9 percent protection from cardiovascular deaths and a 16 percent reduction in cardiovascular events. One of the studies, the Oslo Diet Heart Trial, provided fatty fish as a source of omega-3 fats to the intervention group. When the results of this trial were omitted, cardiovascular mortality risk dropped to 6 percent and cardiovascular events dropped to 14 percent. A low-fat diet, tracked for longer than two years, showed greater protective benefits. The results were similar for participants with a high initial cardiovascular risk and those with a low cardiovascular risk. However, participants initially classified as "low risk" were subsequently found to have a cardiovascular event rate of more than 2.5 events per 100 people per year, which is quite high. Only two of the trials included women.

The trials included may not reflect current information, because studies that focused on omega-3 fats were omitted as was the Lyon Diet Heart Study, which showed the benefit of a Mediterranean diet. The modest results of this meta-analysis show that the "standard" medical approach to dietary prevention of cardiovascular disease needs further investigation.

—British Medical Journal 2001 March 31; 322(7289):757-63.