Eat fish -- especially if you drink high levels of alcohol

Results are published in the August issue of Alcoholism: Clinical & Experimental Research.

"Essential fatty acids are important building blocks of living cells, making up a substantial part of cell walls," explained Norman Salem, Jr., chief of the Laboratory of Membrane Biochemistry & Biophysics at the National Institute on Alcohol Abuse and Alcoholism "EFAs also have many biological functions, and a lack of them leads to loss of growth and development, infertility, and a host of physiological and biochemical abnormalities." Salem is also the study's corresponding author.

The most important EFAs are polyunsaturated fatty acids (PUFA), said J. Thomas Brenna, professor of human nutrition and of chemistry & chemical biology at Cornell University. Particularly two types, Brenna noted: the omega-6 PUFA linoleic acid (LA), also called n-6 fats, and the omega-3 PUFA linolenic acid (ALA), also called n-3 fats. "Most Americans consume adequate amounts of LA in their diets through the use of vegetable oils, but tend to have low intakes of ALA," said Brenna.

This imbalance, added Salem, has become pronounced only in the last century and many believe it is a source of the increase of many common diseases in Western society. Salem and his co-authors wanted to investigate what influence alcohol consumption might have on EFA imbalance in the Western diet.

Researchers used data from 4,168 adults who self-reported their alcohol consumption as part of the 2001-2002 National Health and Nutrition Examination Survey. Participants were also interviewed about their EFA intake during a single previous 24-hour period.

Results indicate that EFA intake drops as alcohol consumption increases, particularly among men.

"Our most important finding is the decrease in n-3 EFA intake in binge-drinking men," said Salem. "We really couldn’t evaluate women who binge drink two or more times per week due to the low numbers in this population, although it is quite possible that we would obtain similar findings. The changes we found indicate that those who drink alcohol make food selections in such a way as to decrease foods with this important nutrient. The binge-drinking men have decreases in the longer chain n-3 fatty acids, the ones that we typically get from eating fish, and so this suggests that they eat less fish."

"Previous studies by Dr. Salem and colleagues have shown that requirements for these nutrients actually increase with greater alcohol consumption," noted Brenna. "Considering that the ALA levels are already low compared to the LA levels, these results are further reason for concern over the ALA intake of alcoholics."

"This helps to explain why alcohol abuse leads to losses in polyunsaturated fats in the circulation and organs," said Salem. "However, dietary influence does not explain all of the changes observed in past studies of fatty-acid changes in organs of alcohol abusers. Alcohol also has an effect on fatty acid metabolism, mainly through increasing fat break down."

Furthermore, said Brenna, alcohol has strong, lasting, and deleterious effects on the brain. "The brain depends on a supply of omega-3 PUFA," he said. The brains of men consuming high levels of alcohol, particularly those who regularly binge drink, are further compromised by a low intake of EFA."

"In summary," said Salem, "for those who drink, especially binge drinkers or those who drink more than one drink per day on average: make sure that you obtain your sources of n-3 fatty acids in the diet, that is, eat more fish."

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Alcoholism: Clinical & Experimental Research (ACER) is the official journal of the Research Society on Alcoholism and the International Society for Biomedical Research on Alcoholism. Co-authors of the ACER paper, “Alcohol Consumption and Fatty Acid Intakes in the 2001-2002 National Health and Nutrition Examination Survey,” were: Soo Yeon Kim (first author) of the Laboratory of Membrane Biochemistry and Biophysics at the National Institute on Alcohol Abuse and Alcoholism (NIAAA), Rosalind A. Breslow of the Division of Epidemiology and Prevention Research at NIAAA; and Jiyoung Ahn of the Nutritional Epidemiology Branch in the Division of Cancer Epidemiology and Genetics at the National Cancer Institute.

Contact: Norman Salem, Jr., Ph.D.
nsalem@niaaa.nih.gov
301-443-2393
National Institute on Alcohol Abuse and Alcoholism

J. Thomas Brenna, Ph.D.
jtb4@cornell.edu
607-255-9182
Cornell University

Alcoholism: Clinical & Experimental Research