DHA

Docosahexaenoic acid (DHA) is an omega-3 fatty acid with 22 carbons and six double bonds (22:6n-3). It is a major structural lipid in neural tissue and the retina, where it is incorporated into phospholipids and supports membrane function. In humans, DHA is highly enriched in brain and visual tissues and is linked to brain development and maintenance of membrane properties and signaling.

Endogenous synthesis from alpha-linolenic acid (ALA) is possible but limited, making dietary DHA an important source. Dietary DHA comes mainly from fatty fish and other seafood, as well as algae-derived supplements and foods fortified with DHA. Algae-based DHA provides a vegetarian or vegan option and is commonly used for infant formula fortification.

In nutrition and health, DHA is often discussed with EPA (eicosapentaenoic acid). The evidence for DHA’s role in preventing cognitive decline or cardiovascular disease is mixed, with guidelines varying by region. Some organizations recommend daily intakes around 200–300 mg DHA for healthy adults, and higher amounts during pregnancy and lactation to support fetal and infant development.

Safety and intake considerations include potential exposure to environmental contaminants in certain fish, so choosing lower-mercury sources or algae-based DHA can mitigate risk. DHA supplements are available in triglyceride or ethyl ester forms and are generally stable but susceptible to oxidation; proper storage in a cool, dark place is advisable.