Fatty fish such as tuna, herring, mackerel, sardines, pilchards, trout and salmon are thought to be beneficial to the health because they contain polyunsaturated fatty acids. Docosahexanoic acid (DHA) and eicosapentanoic acid (EPA) are both long chain polyunsaturated fatty acids present in fish and have been investigated with reference to their ability to protect humans from a number of degenerative diseases. In research EPA and DHA have shown promise for their ability to prevent cardiovascular disease, cancer, dementia and diabetes. The Mediterranean diet and Japanese diet are thought to be protective of cardiovascular disease in part because of their high intakes of long chain fatty acids from fish. Both EPA and DHA are available in supplements which are becoming increasingly popular. However, questions arise as to the most effective method of increasing the cellular levels of EPA and DHA.
Research published in the American Journal of Clinical Nutrition in 20071, compared the enrichment of red blood cell (RBC) membranes with long chain fatty acids from fish or supplements. Healthy female subjects were fed 485 mg of EPA and DHA from either 2 servings of oil fish per week or equivalent from 1 to 2 capsules per day. The results showed that after 16 weeks the group consuming the fatty fish and capsules had a similar increase in EPA and DHA in RBC (from 4 to 6.2 % and from 4.3 to 6.2 % of total fatty acids, respectively). The accumulation of EPA in RBC was faster for the first 4 weeks in those subjects consuming fatty fish compared to the capsules, but after this time the rates stabilised, such that there was no significant difference subsequently.
These results indicate that fish oil supplements are as effective as fish at raising RBC membrane levels of long chain polyunsaturated fatty acids. The current recommendation for cardiovascular health is to eat fatty fish more than two times a week, but this viewpoint has been under scrutiny recently because of the growing amount of pollutants found in these fish. Some fatty fish may accumulate environmental toxins present in the water from industrial waste, including mercury, polychlorinated biphenyls (PCB) and dioxins. Generally the higher up the food chain the greater the pollution found in the fish. Fish oil supplements are an effective way to attain the benefits of fatty fish, but without the pollution. However, in order to take advantage of this a high quality fish oil supplements that has been treated to remove the toxins must be consumed.
RdB
