Written by Marcia J. Egles, MD. The study concluded that both fish and fish oil capsules are equally useful in bolstering omega-3 concentrations in the body.
Omega-3 fatty acids, also known as n-3 fatty acids, are important nutrients which the body needs and cannot make from other food sources. Omega-3 fatty acids have been shown to be beneficial to heart and vascular health (1). The omega-3 group of fatty acids includes alpha-linolenic acid (ALA), eicopentenoic acid (EPA) and docosahexenoic acid (DHA). Oily ocean fish like salmon and tuna are rich in omega-3 fatty acids.
This study sought to examine whether or not the consumption of fish oil capsules is biologically equivalent to the same amount of oil obtained by eating cooked fish. Only scant information from previous studies addresses the presumption that both sources would be the same. After analysis of the blood of two study groups, one fed fish oil and one fed fish, this study found no significant differences.
Twenty-three healthy pre-menopausal female volunteers, ages 21 to 49, were randomly assigned to each of two groups for a sixteen week study. One group was to ingest one to two fish oil capsules per day. The other group was to eat fish. In the fish group, the women ate three six-ounce portions of canned tuna plus one six- ounce Atlantic (farmed and frozen) salmon fillet during each two-week period of the study. They were to eat only the fish provided in the study, but they could prepare it at home any way they wished. The two groups were designed to receive the same type and amounts of omega-3 fatty acids. The average daily amount of the omega-3 fatty acids, EPA plus DHA, was estimated to be 485 milligrams for each participant in both groups.
At baseline and every two weeks thereafter for sixteen weeks, the participants’ blood was collected and analyzed. The researchers looked at the fatty acid composition of both the red blood cells and the cell-free part of the blood, the plasma. They monitored how well the red blood cell membranes and the plasma lipids became enriched by the omega-3 fatty acids in the two groups. They found that during the first month of the study, the EPA content of the red blood cell membranes of the fish group rose 7 per cent faster than the capsule group. After the first month however, there were no significant differences detected between the two groups, and the early rise in the fish group was considered inconsequential.
For prevention of heart disease, the American Heart Association has in general recommended the intake of two servings of fish per week (2), the same amount used in this study. For those with known heart disease, they recommend twice this amount. The study concluded that both fish and fish oil capsules are equally useful in bolstering omega-3 concentrations in the body. They noted the additional benefit of fish in providing protein and trace minerals such as selenium. Fish oil capsules offer freedom from the mercury contamination that can occur with fish. Capsules are also convenient. Both fish and fish oil capsules would be expected to help lower the risk of heart disease.
Source: Harris, William S., et al. “Comparison of the effects of fish and fish-oil capsules on the n–3 fatty acid content of blood cells and plasma phospholipids.” The American journal of clinical nutrition 86.6 (2007): 1621-1625.
© 2007 American Society for Nutrition
Posted July 2, 2008.
References:
- Kris-Etherton PM, Harris WS, Appel LJ. Fish consumption, fish oil, omega-3 fatty acids and cardiovascular disease. Circulation 2002; 106: 2747-57.
- American Heart Association www.americanheart.org/presenter.jhtml?identifier=4632
