In 1989, a large-scale study of omega-three fatty acid supplementation with fish oil in MS was completed. The results of the study showed a trend towards improvement in the treatment group, but this trend was not statistically significant.
Another, smaller study combined supplements with glatiramer acetate (Copaxone) or interferons (Rebif, Betaseron, Avonex). Conventional MS medications and low-fat diets were combined with either olive oil intake or fish oil intake. Emotional and physical functioning in the fish oil group trended towards improvement, although the trend was not statistically significant. Both groups benefited from a decrease in attack rates.
Other immune diseases have seen benefits from omega-three fatty acid supplements. In rheumatoid arthritis, omega-three fatty acids may decrease joint swelling and stiffness.
Omega-three fatty acids may also have the potential to prevent or treat heart disease, as they mildly decrease blood pressure and triglycerides levels.
Sources of Omega-Three Fatty Acids.
Fish and other seafood are amongst the most common food sources of omega-three fatty acids. Fatty fish, such as salmon, Atlantic mackerel, Atlantic herring, sardine, bluefin tuna, and cod liver, are especially good sources of omega-three fatty acids. It is sometimes recommended that two or three servings of fish be consumed weekly.
It is also possible to consume omega-three fatty acids in supplements. As with omega-six fatty acids, the optimal dose is not known, nor is the appropriate ratio of omega-six to omega-three fatty acids.
Omega-three fatty acids are available as supplements. Both fish oil and cod liver oil are available in liquid form or in capsules. It is also possible to buy concentrated EPA and DHA. It is believed that doses of three grams or less a day are safe.
Risks of Omega-Three Fatty Acids.
Consumption of large amounts of fish raises about mercury toxicity. Women who are pregnant or may become pregnant should be especially wary of excessive fish intake. Relatively high levels of mercury are found in shark, king mackerel, and swordfish. Mercury contamination does not appear to be an issue with fish oil supplements.
The U.S. Food and Drug Administration (FDA) determined fish oil supplements to be safe when doses of DHA and EPA were kept below 3 grams daily. One seven-year study found no adverse effects associated with long-term use of fish oil.
Cod-liver and flaxseed oil have unpleasant tastes, which can be mitigated by cooling. Intake of more than 45 grams of flaxseed oil a day can have a laxative effect.
Omega-three fatty acids can produce vitamin E deficiency. As a result, supplemental vitamin E may be indicated. Although fish oil products do not usually contain vitamin A, shark, halibut, and cod-liver oils may contain large amounts of vitamin A. High levels of vitamin A can be toxic, especially for women who are pregnant. As a result, excessive intake of these oils should be avoided.
In people who are aspirin-sensitive, omega-three fatty-acid supplements can impair lung function. People with diabetes may experience increases in blood sugar levels. In people with manic-depressive illness and depression, these supplements may produce hypomania, a condition characterized by excessive mental and physical activity. The safety of these supplements for women who are pregnant or breast-feeding has not been established.
Fish oils, especially EPA, may interfere with blood-clotting and thus should be avoided by people with blood-clotting disorders, people who are taking blood-thinning medications (including high doses of aspirin), and those who are undergoing surgery.
Vitamin E and Polyunsaturated Fatty Acids
It is important to note that polyunsaturated fats may decrease levels of vitamin E in the body. If large quantities of polyunsaturated fat are taken, vitamin E intake must be increased. High doses are not necessary—in fact, as an antioxidant, they may even have negative consequences for people with MS. Many suggest that 0.6 to 0.9 international units (IU) of vitamin E be consumed for every gram of polyunsaturated fatty acid.
References and Additional Reading
Bowling AC. Complementary and Alternative Medicine and Multiple Sclerosis. New York: Demos Medical Publishing, 2007.
Bowling AC, Stewart TS. Dietary Supplements and Multiple Sclerosis: A Health Professional’s Guide. New York: Demos Medical Publishing, 2004.
Jellin JM, Batz F, Hitchens K, et al. Natural Medicines Comprehensive Database. Stockton, CA: Therapeutic Research Faculty, 2009.
Ulbricht CE, Basch EM, eds. Natural Standard Herb and Supplement Reference: Evidence-Based Clinical Reviews. St. Louis: Elsevier-Mosby, 2005.