Docosahexaenoic Acid (DHA)


DHA is a member of the omega-3 group of fatty acids. DHA is also one of the most abundant fatty acids in the brain. In the fetus and young infants, DHA is essential for proper growth and development of the brain, (1) , (2) nervous system, and the retina of the eye. Because DHA is present in breast milk and not in cow’s milk, many physicians recommend breast-feeding or the use of infant formula that contains DHA.

The richest dietary sources of DHA are the oils from cold water fish such as salmon, mackerel, herring, sardines, and other marine animals. DHA is also produced in the body, but it must be derived from alpha-linolenic acid, which is found in flaxseed oil.

Dosage Info

Dosage Range

250-1,000mg daily.

Most Common Dosage

500mg daily.

Dosage Forms

Capsules and tablets.

Interactions and Depletions


Reported Uses

Scientists think DHA is primarily involved in the growth and development of the brain and nervous system, (3) as well as the retina. However, these functions may make it useful for the treatment and support of a number of health conditions.

Studies suggest that children with attention deficit disorder (ADD) and attention deficit hyperactivity disorder (ADHD) may be deficient in DHA. (4) However, DHA supplementation in ADHD individuals may not be as effective as once thought. (5) People with schizophrenia may also be deficient (6) , (7) and DHA has improved some of the symptoms associated with the disease. (8) Other studies suggest that omega-3 fatty acids like DHA may exhibit mood-stabilizing properties in patients with bipolar disorder, also known as manic-depressive illness. (9) Researchers found that bipolar mood disorder patients had lower levels of DHA than control subjects and that supplementation may be beneficial to the patients. (10)

DHA and other omega-3 fatty acids may help reduce the risk of breast cancer. They may also suppress factors that can contribute to the growth of breast tumors. (11) Animal and cell studies have demonstrated decreased tumor size and decreased cancer cell growth with DHA use. (12) Animal studies also suggest that supplementation with DHA can make several types of chemotherapy, including mitomycin C and cyclophosphamide, both more effective and less toxic. (13) , (14)

The importance of DHA for pre-term and full-term infants cannot be overemphasized. Studies suggest that infants receiving supplemental DHA in their infant formulas scored significantly higher in mental development, as gauged by memory, problem solving, and related skills. (15) , (16) DHA is also essential for the development of the brain (17) and eyes in infants and has shown benefit in vision studies. (18) Physicians stress that pre-term infants should be supplemented with DHA since these infants are often incubated and not breast-fed. (19) It is also important that mothers breast-feeding their infants be educated about the importance of obtaining optimal intakes of DHA. DHA may also help ease the symptoms for women who experience painful menstruation. (20)

A study evaluated a group of patients suffering from sickle cell disease while providing them with a fish oil that contained 12% EPA and 18% DHA. This treatment decreased the number of pain episodes requiring hospitalization by almost one-half. (21)

Results from several studies indicated that supplementation of DHA may be of benefit to X-linked retinitis pigmentosa patients. (22) , (23) Also, a study provided information as to the safety of DHA supplementation over a long period of time. (24)

Individuals with a genetic disorder known as Zellweger syndrome are known to have low levels of DHA. (25) Patients treated with DHA had improved vision and muscle function, as well as MRI-documented improvements in myelination, a coating found on nerves that enhances the conduction of nerve impulses. Treatment has been most successful when initiated before 6 months of age. (26)

As with other omega-3 fatty acids, DHA may support long-term health of the cardiovascular system. More specifically, DHA may help prevent heart disease and help lower harmful fat levels in the blood stream. (27) , (28) , (29) , (30) One study noted that DHA not only lowered the harmful fat and cholesterol levels in the body, but also improved the elastic nature of the arteries. (31) Arteries that have poor elasticity may indicate cardiovascular disease.

Toxicities & Precautions


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People who take supplemental DHA are advised to take additional antioxidants, especially vitamin E, to protect against free radical damage to DHA in the body.

Side Effects

People who take a fish oil form of DHA may experience belching that causes a “fishy" odor. (32)

Pregnancy / Breast Feeding

To date, the medical literature has not reported any adverse effects related to fetal development during pregnancy or to infants who are breast-fed. Yet little is known about the use of this dietary supplement while pregnant or breast-feeding. Therefore, it is recommended that you inform your healthcare practitioner of any dietary supplements you are using while pregnant or breast-feeding.

Age Limitations

To date, the medical literature has not reported any adverse effects specifically related to the use of this dietary supplement in children. Since young children may have undiagnosed allergies or medical conditions, this dietary supplement should not be used in children under 10 years of age unless recommended by a physician.


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  27. View Abstract: Simon J, et al. Serum Fatty Acids and Risk of Coronary Heart Disease. American Journal of Epidemiology. 1995;142(5):469-476.
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  30. View Abstract: Lovegrove JA, Lovegrove SS, Lesauvage SV, et al. Moderate fish-oil supplementation reverses low-platelet, long-chain n-3 polyunsaturated fatty acid status and reduces plasma triacylglycerol concentrations in British Indo-Asians. Am J Clin Nutr. Jun2004;79(6):974-82.
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