Clinical trial · Supplements / medicine · 18 Jun 2026
High-dose DHA reached the brain but did not slow memory or hippocampal loss in an Alzheimer’s-risk trial
Source: EurekAlert
What the research found
Study (phase 2a RCT). Hussein N. Yassine and Keck Medicine of USC colleagues report in eBioMedicine (NCT03613844) on 365 adults aged 55–80 without dementia (mean age 66.4; 58% female; 47% APOE ε4; low dietary DHA) randomised to 2 g/day DHA or placebo for 24 months. CSF DHA/AA rose at six months (about 17% higher CSF DHA) and the red-cell omega-3 index rose from 4.9% to 11%, showing the fatty acid reached the brain independent of APOE ε4. Over 24 months there were no treatment differences in cognition (RBANS) or hippocampal volume; dropout was 38%, mainly COVID-related. Null result: high-dose fish-oil DHA is not shown here as Alzheimer’s prevention. Food-first omega-3 remains a dietary pattern question. Educational supplement notes, not a prescription to start or stop fish oil, and not a dementia diagnosis.
Evidence level: Clinical trial. This is among the stronger kinds of evidence, but one study rarely settles a question.
More supplements / medicine news
- In mice, the experimental drug KCL-286 reduced DNA breaks and brain inflammation in an Alzheimer's model
- In aged rats, two weeks of the experimental drug cinaciguat cut circulating amyloid-beta about in half and brought LDL down to youthful levels
- In 104 people with a sudden retinal-artery blockage, papaverine use lined up with better functional vision in a retrospective comparison
- A Cell Metabolism letter questions whether a fasting GLP-1 level shows how many gut L-cells a person has
- In FDA reports, caffeine and stimulant supplement use was tied to cardiac arrest about 11 times more often, and 45 percent of those cardiovascular reports were ages 18 to 34