News Release

Genetics, not just diet, influence cholesterol levels

Peer-Reviewed Publication

American Journal of Clinical Nutrition

Some genetic variables can cause individuals to be resistant to a cholesterol-lowering diet or at greater cardiovascular risk from a high-fat diet, according to new research published in The American Journal of Clinical Nutrition. Rantala et al. at the University of Oulu in Finland and the Hebrew University of Jerusalem studied apolipoprotein B ("apo-B"), a protein essential for lipid transport, which can be affected by both diet and genetics. Apo-B lipoproteins in the blood are associated with increased risk of cardiovascular disease. Results of the study demonstrated that subjects with one or more specific genotypes showed much greater rises and falls in cholesterol levels in response to diet than did other genotypes studied.

The 22 male and 22 female volunteers were all Finnish hospital employees and underwent initial screening to determine their lipid-related phenotypes before any dietary intervention began. Five apo B mutation sites were examined for their effects on the fluctuation in subjects' blood lipid concentrations. During the six months of the study, the subjects were rotated from their usual diet ( for 3 months), to a low-fat diet (1 month), a high-fat diet (1 month) and back to their usual diet (1 month). Blood samples collected throughout this period were analyzed for plasma total cholesterol, HDL-cholesterol and LDL-cholesterol levels, and the values were compared with the subjects' various genotypes. One genotype in particular, the "X-/X-" genotype, showed the greatest increase in plasma total and LDL cholesterol during the high-fat diet, as well as the greatest decrease during the low-fat diet. Two other genotypes, "M+/M+" and "R-/R-" also demonstrated greater cholesterol sens itivity in response to the changes in diet.

In addition the authors performed a meta-analysis of 14 previous studies conducted between 1980 and 1998. Although the meta-analysis did not support all of the results of their own dietary trial, it did show some of the same associations between the "M+/M+" and "R-/R-" genotypes and higher plasma total cholesterol concentrations. The authors suggest that there is so much genetic variability among study subjects that a great deal more research in this field will need to be done before genetic counseling for cholesterol-lowering diets becomes a commonplace practice.

###

Rantala, M et al. Apolipoprotein B gene polymorphisms and serum lipids: meta-analysis and the role of genetic variation in responsiveness to diet. Am J Clin Nutr 2000; 71:713-724.

For more information contact: Dr. M. Rantala at Maire.Rantala@oulu.fi

This media release is provided by The American Society for Clinical Nutrition, to provide current information on nutrition-related research. This information should not be construed as medical advice. If you have a medical concern, consult your doctor.


Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.