DHA is crucial for adult brain function, and for the development of our nervous system and visual abilities during the first six months of life. Insufficient DHA is associated with a host of mental and visual functioning issues, including, in children, attention-deficit hyperactivity disorder (ADHD) in childred and depression and Alzheimer's disease.

While prescription of fish oil for heart attack survivors is standard practice in Europe, American doctors have been slow to accept the therapy: "Because prescription fish oil is not licensed to prevent heart disease in the United States, drug companies may not legally promote it" the Times states, adding that his disconnect between what is known about fish oil and its underuse "highlights the central role that drug companies play in disseminating medical information, experts said."

Fish oil has also shown promise as an anti-inflammatory treatment for conditions such as rheumatoid arthritis, menstrual pain, and lupus. In addition, it may be helpful for various psychiatric conditions.

The Food and Drug Administration has allowed supplements containing fish oil or its components to carry a label that states: "Supportive but not conclusive research shows that consumption of EPA and DHA omega-3 fatty acids may reduce the risk of coronary heart disease."

Pregnant or nursing women may want to seek out algae-based DHA supplements, which do not contain EPA, which can impact the DHA / EPA balance, crucial for intfant development.