Docosahexaenoic acid (DHA) is an omega-3 fatty acid that is a primary structural component of the human brain and retina and is manufactured internally by α-linolenic acid. Although α-linolenic acid (ALA) does convert to DHA in humans, the process is inefficient and very limited even in healthy individuals. Most of the DHA in fish and complex organisms with access to cold-water oceanic foods originates in photosynthetic and heterotrophic micro algae (Crypthecodinium cohnii), and becomes increasingly concentrated in organisms, as they move up the food chain. Dietary DHA may reduce the risk of heart disease by reducing the level of blood triglycerides in humans. During the last 50 years, many infants have been fed formula diets lacking DHA and other omega-3 fatty acids. Its deficiencies are associated with foetal alcohol syndrome, attention deficit hyperactivity disorder, unipolar depression, heart disease, aggressive hostility. A new study found that higher intake of DHA was associated with slower rates of telomere shortening, which is a basic DNA-level marker of aging. Its decrease in the brain is associated with onset of sporadic Alzheimer disease. Epidemiological studies have shown a strong correlation between fish consumption and reduction in sudden death from myocardial infarction. The reduction is approximately 50% with 200 mg per day of DHA from fish. It is available as a supplement in two forms: Fish oil capsule (contains both DHA and EPA i.e. eicosapentaenoic acid) and DHA from algae (contains no EPA). Fish oil reduces triglycerides in the blood, decrease thrombosis, and prevents cardiac arrhythmias, rheumatoid arthritis, menstrual pain, Raynaud’s syndrome, and lupus. Side effects such as loose stools, stomach upset,
and belching may be associated with use of fish oil capsule.
Keywords: Alpha linolenic acid, Fatty acid, Arachidonic acid, Eicosapentaenoic acid.