TL;DR
Get health and wellness essentials delivered free with Prime
- Fast, free delivery on millions of items
- Prime Video, Amazon Music and more included
- Member-only deals all year
In a two-year randomized trial, older adults at elevated Alzheimer’s risk who took daily DHA supplements had no measurable cognitive advantage over those given a placebo. DHA levels in cerebrospinal fluid rose, but researchers found no protection against shrinkage of the hippocampus. The findings apply to the study group and do not establish whether fish eaten as part of a broader diet has the same effects.
A two-year clinical trial found that daily fish oil supplements did not measurably improve memory or other thinking abilities, or prevent shrinkage in a brain region important for memory, among 365 older adults at elevated Alzheimer’s risk. The study, led by researchers at Keck Medicine of USC and published in eBioMedicine, found that DHA levels rose in participants’ cerebrospinal fluid, but that increase did not translate into a detectable benefit compared with placebo.
Participants were 55 to 80 years old, rarely ate fish and were considered at increased risk of Alzheimer’s disease. Nearly half, or 47%, carried the APOE4 gene variant, which is associated with higher risk of late-onset Alzheimer’s. Carrying APOE4 does not mean a person will necessarily develop the disease.
Researchers randomly assigned participants to take either a daily supplement providing 2,000 milligrams of DHA, an omega-3 fatty acid, or a placebo. The trial was double-blind, meaning participants and researchers did not know who was receiving the active supplement while the study was underway.
After six months, cerebrospinal fluid measurements showed an average 17% increase in DHA among those taking supplements. At the two-year assessment, however, cognitive test results did not show a significant advantage over placebo. Brain imaging also found no evidence that the supplements prevented shrinkage of the hippocampus, a region involved in forming and organizing memories.
What the Results Mean for Supplement Users
The results challenge the expectation that taking fish oil will, by itself, protect memory as people age. The trial tested a specific supplement and dose in older adults who rarely ate fish and had elevated Alzheimer’s risk; it found no measurable benefit on the outcomes studied over two years, even though DHA reached the central nervous system.
That distinction matters: the finding does not show that omega-3 fatty acids have no role in the body or brain, nor does it establish that fish or a balanced dietary pattern has no relevance to health. Rather, the results do not support using this daily DHA supplement as a proven way to prevent Alzheimer’s or preserve cognition in a group like the one studied. People considering supplements for their own health can discuss their circumstances with a qualified health professional.
DHA omega-3 fish oil supplements 1000 mg softgels
As an affiliate, we earn on qualifying purchases.
As an affiliate, we earn on qualifying purchases.
How Researchers Tested DHA in the Brain
Omega-3 fatty acids are nutrients found in foods including fish, and DHA is a major component of brain cell membranes. The study authors noted that DHA supports the structure and communication of nerve cells, providing a biological reason to investigate whether increasing it might help maintain cognition. That rationale, however, is not the same as evidence that a supplement prevents disease.
The researchers measured DHA in cerebrospinal fluid to check whether the supplement affected levels in the central nervous system. The observed increase showed that DHA levels rose in that fluid; the subsequent cognitive tests and imaging addressed a separate question: whether the change produced a detectable improvement in brain health. In this trial, it did not.
The study report says the researchers are investigating whether the brain’s handling of omega-3s varies with factors such as age, genetic risk, health and overall diet. It also describes a Mediterranean-style dietary pattern, which includes fish alongside vegetables, fruits, whole grains, legumes, nuts and olive oil, as a possible area for further study. The trial did not test that dietary pattern against a placebo.
third-party tested omega-3 fish oil supplement EPA DHA
As an affiliate, we earn on qualifying purchases.
As an affiliate, we earn on qualifying purchases.
Questions the Trial Did Not Answer
The findings do not establish whether a longer trial, a different dose, or supplements taken by people with different diets or health profiles would produce another result. The study was limited to older adults who rarely ate fish and were at elevated risk; its results should not automatically be applied to all ages, dietary habits or levels of Alzheimer’s risk.
The trial also does not determine whether eating fish or following a Mediterranean-style diet affects cognitive outcomes. Those were not the intervention being tested. The available report provides no evidence that the supplement reduced Alzheimer’s diagnoses, and the reported measures were cognitive test performance and hippocampal shrinkage over two years. How differences in diet, age, health and genetics might affect the brain’s use of DHA remains under investigation.
omega-3 rich canned sardines in olive oil
As an affiliate, we earn on qualifying purchases.
As an affiliate, we earn on qualifying purchases.
Researchers Examine Diet and DHA Use
Yassine and colleagues are investigating how the brain absorbs, processes and uses omega-3 fatty acids, according to the study report. They are exploring whether factors such as dietary pattern, age, genetic risk and general health may change the effects of DHA. The report does not give a timetable for additional findings or identify a next clinical trial.
For now, the clearest conclusion is limited to the tested regimen and group: daily DHA supplementation did not produce measurable cognitive or hippocampal benefits over two years. Further research would be needed to determine whether other approaches, including omega-3s as part of a broader diet, change that outcome.
omega-3 rich canned salmon wild caught
As an affiliate, we earn on qualifying purchases.
As an affiliate, we earn on qualifying purchases.
Key Questions
Did fish oil improve memory in the trial?
No measurable improvement was found. Over two years, participants taking DHA performed no better on cognitive tests than participants receiving a placebo.
Did the supplement reach the brain?
DHA levels in participants’ cerebrospinal fluid rose by an average of 17% after six months. That increase did not lead to a measurable advantage in cognitive tests or protection against hippocampal shrinkage.
Who took part in the study?
The trial enrolled 365 adults aged 55 to 80 who rarely ate fish and were considered at elevated risk of Alzheimer’s disease. Forty-seven percent carried APOE4, a genetic risk variant.
Does this prove that eating fish does not support brain health?
No. The trial tested a daily DHA supplement, not fish or a Mediterranean-style diet. Its findings do not answer whether omega-3s consumed as part of food or an overall dietary pattern affect cognition.
Does carrying APOE4 mean someone will develop Alzheimer’s?
No. APOE4 is associated with increased risk of late-onset Alzheimer’s, but carrying the variant does not mean a person will necessarily develop the disease.
Source: rss
Cold & flu season Picks
humidifiers
As an affiliate, we earn on qualifying purchases.
