Docosahexaenoic Acid
Docosahexaenoic acid (DHA) is a long-chain omega-3 fatty acid found in fatty fish and algae. It is especially concentrated in the brain and retina.
Also listed as DHA, DHA (Docosahexaenoic Acid)
Does DHA improve memory?
A 2015 review found a small benefit for episodic memory, the recall of events, in adults with mild memory complaints, but not a clear benefit across all participants. Working and semantic memory did not improve relative to controls. Studies used DHA alone or with EPA; the review had omega-3 industry funding. 1
Can it slow Alzheimer disease?
In 402 adults with mild to moderate Alzheimer disease, 2 g of algal DHA daily for 18 months did not slow cognitive or functional decline compared with placebo. This treatment trial does not answer whether lifelong dietary intake affects disease risk. 2
What does pregnancy research show?
A Cochrane review of 70 trials found fewer births before 37 weeks with added long-chain omega-3s: 11.9% versus 13.4%. Pregnancies beyond 42 weeks probably increased. The interventions included different omega-3 foods and supplements, so the pooled result is not an isolated-DHA estimate. 3
Added long-chain omega-3 intake reduced preterm birth in the review; product and pregnancy context still matter. 3
Does DHA lower cholesterol?
A review of six studies using more than 2 g/day of highly purified EPA or DHA found lower triglycerides with both. DHA also raised LDL cholesterol. Lower triglycerides therefore should not be described as an across-the-board cholesterol improvement. 4
Does its role in the eye translate into prevention?
DHA is concentrated in the retina, but a trial of combined EPA and DHA in healthy people did not prevent dry eye over 5.3 years. 5
What is outside this review?
This page does not evaluate DHA for inflammation, attention disorders or low energy; eye findings here concern dry eye prevention only.
Effects by health goal
Open an effect to see the studies behind its rating. Bars show the size of the effect; the letter grades the evidence.
Cardiovascular1 effect
Organ Function1 effect
Women's Hormones1 effect
Cognition4 effects
Fertility1 effect
All studies
19 publications are linked to Docosahexaenoic Acid, newest first.
Sources
- Omega-3 fatty acid addition during pregnancy Cochrane, 2018
- Omega-3 Fatty Acids: Consumer Fact Sheet NIH Office of Dietary Supplements