Cod Liver and Flax Oil

Cod liver oil and flax oil both contain omega-3 essential fatty acids; however, the omega-3 fatty acids in cod liver oil appear to be more potent, according to Artemis P. Simopoulos, M.D., F.A.C.N. of the Center for Genetics in Washington. Cod liver oil also provides important vitamins. That said, flax oil offers a decent source of omega-3 fatty acids for vegetarians and people who prefer not to eat fish, and compounds in flax oil may act as a cancer preventative.

EPA and DHA

Cod liver oil provides abundant sources of the omega-3 fatty acids eicosapentaenoic acid, or EPA, and docosahexaenoic acid, or DHA. According to a December 2002 article published in the "Journal of the American College of Nutrition," EPA and DHA reduce the level of interleukin-1, an inflammatory protein associated with many serious diseases including coronary heart disease and cancer. EPA and DHA also minimize the symptoms of inflammatory autoimmune diseases such as lupus, arthritis, Crohn's disease and psoriasis.

ALA

ALA stands for alpha-linolenic acid, a form of omega-3 essential fatty acids derived from plants. Flax oil is a rich source of ALA. Once ingested the body converts ALA into EPA and DHA; however, the rate of conversion appears to be quite low, according to a 1998 Swiss study published in the "International Journal for Vitamin and Nutrition Research." Researchers learned that ALA conversion results in a net gain of only 6 percent EPA and less than 4 percent DHA.

Lignans

Flax oil contains important phytonutrients known as lignans; lignans are phytoestrogens, or plant compounds that mimic the action of estrogen in the body. According to the NYU Langone Medical Center, the lignans in flax oil evacuate excess estrogen from the cells and so inhibit the ability of hormone-dependent cancers such as breast cancer to take root and grow.

Vitamin A

Cod liver oil also provides a good source of vitamin A. This vitamin regulates immune system function, promotes healthy vision and healthy bones, and strengthens the mucus membranes against bacteria. One tbsp. of cod liver oil contains 270 percent of the daily recommended value of vitamin A.

Vitamin D

One tbsp. of cod liver oil offers 338 percent of the recommended daily allowance of vitamin D. This important vitamin facilitates the absorption of calcium to maintain strong bones and teeth. Vitamin D also supports neuromuscular function and immune system function; according to the National Institutes of Health Office of Dietary Supplements, vitamin D also suppresses chronic inflammation in the body.