DHA is short for docosahexaenoic acid. This substance is in the family of omega-3 fatty acids. It plays a role in the proper functioning of the brain. The human body naturally produces DHA, however it does not make enough to meet its own needs. People who consume diets that include small amounts of omega-3 fatty acids may choose to take DHA supplements.
This omega-3 fatty acid is naturally found in many cold-water fish. Salmon and bluefin tuna have abundant amounts of natural DHA, as do sardines and mackerel. DHA supplements contain this extracted acid.
The supplements are commonly available in the form of fish oil capsules. These also typically contain another omega-3 fatty acid, called eicosapentaenoic acid (EPA). Consumers may also choose to use DHA supplements that are extracted from algae. These supplements generally do not contain EPA.
While there is no standardized dosage for DHA supplements, an adult may take between 3,000 to 4,000 milligrams (mg) each day. Users should check the label of the specific product for the correct dosage of omega-3 acids. For example, a supplement that advertises 1,200 mg of fish oil may only contain 720 mg of DHA.
Consumers who use DHA supplements that are extracted from algae may take 200 mg daily. While pregnant women are often advised to take 200 mg of DHA daily, they — or those that are nursing — should consult with a doctor before taking any such product. Parents and guardians should check with a pediatrician about appropriate dosages before administering supplements to a child.
In addition to maintaining overall health and brain function, a patient may take these supplements for specific health concerns. For instance, some people may use this acid as complementary therapy for treating attention deficit hyperactivity disorder (ADHD). It may also be taken for depression and menstrual pain. Evidence supporting these possible benefits is inconclusive, however.
It has also been suggested that DHA supplements may ease the symptoms of rheumatoid arthritis. There is stronger evidence regarding the use of fish oil supplements to help prevent heart disease. Omega-3 fatty acids may help lower triglycerides. They may also help lower blood pressure and reduce the accumulation of plaque in a patient's arteries.
Patients should not neglect traditional medical care in favor of supplements. Those who take medications should exercise caution. These capsules may interact with aspirin, blood-thinners, and diabetes medications, as well as blood pressure medications and cyclosporine.
Fish oil supplements may also result in some side effects. These can include prolonged bleeding after an injury and abdominal discomfort. Some patients may experience loose stools. Patients who experience side effects, have a medical condition, or take medications, should consult with a doctor.