Docosahexaenoic acid (DHA) is an omega-3 fatty acid, and the DHA oil derived from it is often used as a dietary supplement. Some research suggests that it may improve brain and eye development in babies, reduce the risk of heart disease, and help to treat Alzheimer's disease and certain types of cancer. Fish oils and certain types of algae contain high levels of DHA, and both can be taken as dietary supplements to increase DHA levels in the body. DHA oil can be added directly to food or taken as a capsule, and it is an added ingredient in certain types of infant formula. DHA that comes from algae is known as vegetarian DHA.
DHA oil has become a popular dietary supplement for pregnant and breastfeeding women, and some prenatal vitamins contain DHA oil. Although there is not conclusive scientific proof of its benefits, some research has shown that DHA can improve brain development and visual acuity in infants and young children. The vegetarian form of DHA oil is often used in prenatal vitamins because it does not have the odor that is sometimes present in fish oil. This strong odor can be difficult for pregnant women, especially those with morning sickness, to tolerate. Certain brands of children's vitamins also contain DHA.
In addition to pregnant women and young children, vegetarians and vegans may also benefit from taking DHA oil. A vegan diet can sometimes be deficient in DHA, because fish is a primary source of it. Vegans and vegetarians who are concerned about getting enough DHA can take a plant-derived form of the supplement. It is not known if lower levels of DHA in the body can lead to health problems.
Some research studies have suggested that DHA may be effective in slowing the growth of cancer cells or making cancer treatments more effective. One study found DHA to be effective in preventing colon cancer, but further research may be needed to validate this use of the supplement. Other studies have shown that DHA can help to make chemotherapy more effective in treating prostate cancer.
Research is still being conducted into DHA oil and its possible health benefits. Some studies suggest that it may be useful in treating or preventing Alzheimer's disease and heart disease. It is also believed to help support cognitive function.