DHA, or docosahexaenoic acid, is an essential fatty acid that is found inside the meat of cold-water fish. Mackerel, tuna, halibut, salmon and herring are all excellent sources of DHA, as are whale and seal blubber. Meat and eggs have low levels of this fatty acid, and new mothers also produce DHA in breast milk while lactating. DHA is commercially packaged into widely available fish oil supplements.
Docosahexaenoic acid is a popular fish oil supplement that is included in some infant formula to promote proper infant brain, eye and nerve development. Eye and nerve tissue development requires DHA. Doctors use DHA to treat depression, migraines, and attention deficit hyperactivity disorder as it has properties that assist central nervous system functions. Known for its anti-inflammatory properties, DHA is often prescribed to patients who have rheumatoid arthritis and lupus.
Studies suggest that DHA may be beneficial in the treatment of certain cancers as it inhibits tumor development. The US National Library of Medicine reports that fish oil may decrease the spread of tumor cells, whereas a long-chain n-6 fatty acid called arachidonic acid increases their spread. Therefore, oncologists recommend a diet that is high in cold-water fish and DHA supplementation for the prevention of cancer and other ailments.