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Diet and Nutrition Critically Important for African-Americans

2011-09-20 09:33

Every racial or ethnic group has specific health concerns due to genetics, cultural or environmental factors or access to care. Researchers are just beginning to consider the impact of gene-diet interactions, for example, to promote best practices for disease prevention and treatment in specific populations. Scientists with Wake Forest Baptist Medical Center have discovered that African-Americans, who are at increased risk for obesity and high blood pressure, process a certain fat differently which cause increased inflammation leading to chronic disease.

Polyunsaturated fatty acids (PUFA) are chemical molecules that contain more than one double bond. Where this bond is located gives the nutrient a particular chemical property. Two essential PUFAs are omega-3 fatty acids and omega-6 fatty acids.

A balance in the dietary intake of these two fatty acids is essential for good health. However, the usual diet in western countries today contains much less omega-3 fatty acids found in oily fish and flaxseed and much more omega-6 fatty acids found in vegetable oils and animal fats. Experts estimate that over the last 75 years, we have increased our daily intake of omega-6 PUFAs from 2.8% of calories to nearly 8%.

Floyd H. Chilton PhD, a professor of physiology and pharmacology and the director of the Center for Botanical Lipids and Inflammatory Disease Prevention, and Rasika Mathias ScD, an assistant professor of medicine and epidemiology at Johns Hopkins School of Medicine, have discovered that Americans of African ancestry more often have a gene variant located in a small region of chromosome 11, known as the FADS cluster (fatty acid desaturase).

The FAD enzyme normally helps to break down fatty acids so they can be used for energy. Genetic interruption to this process has negative impacts on health and development. In the case of African-Americans, the variation causes a conversion of omega-6 fatty acids into inflammatory messengers more often than in European Americans. An increase in inflammation is linked to cardiovascular disease, arthritis, allergies, asthma and diabetes.

“I believe observations such as this begin to address the critical question of why western diets seem to differentially impact African Americans with cardiovascular disease and diabetes at a higher rate than their Caucasian counterparts,” said Chilton. “Understanding which nutrients may be healthy for one population, but not for another will be essential to optimizing public health.”

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Currently, the generalized recommendation from the American Heart Association is to limit the consumption of omega-6 fatty acids to 5 to 10% of total calories. However, this latest research suggests that African-Americans could reduce their risk of chronic diseases by keeping intake of processed and animal foods at the lower end of the recommended range, and focus on obtaining more omega-3 fatty acids from sources such as fish - especially tuna, mackerel and salmon.

“It is critical to study groups such as African Americans because they bear a large proportion of the public health burden of many of the chronic complex diseases of inflammation,” Chilton said.

Journal Reference:

Floyd H. Chilton, Susan Sergeant, et al. “Differences in arachidonic acid levels and fatty acid desaturase ( FADS) gene variants in African Americans and European Americans with diabetes or the metabolic syndrome.” British Journal of Nutrition, Available on CJO 2011 doi:10.1017/S0007114511003230

Additional Reference:
American Heart Association (2009, February 2). Omega-6 Fatty Acids: Make Them Part Of Heart-healthy Eating, New Recommendations Say. ScienceDaily. Retrieved September 20, 2011, from http://www.sciencedaily.com¬/releases/2009/01/090126173725.htm

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