August 28, 2024
Older men and women at high risk for Alzheimer’s disease may benefit from fish oil supplements, according to a new report. The study found that daily fish oil supplements appeared to help protect the brain in older people who carried the APOE-E4 gene variant, which puts people at increased risk of developing Alzheimer’s disease.
The study was small, involving 102 men and women aged 75 and older. But the findings add to growing evidence that fish and the “good” fats they contain, known as omega-3 fatty acids, are good for the brain.
Those in the study did not have serious memory problems, though all had relatively low blood levels of omega-3 fatty acids, the “good” fats found in fish. Half were randomly assigned to take a daily fish-oil supplement over the three-year course of the study, while the others took a placebo pill. The fish oil supplement contained 1.65 grams of omega-3s, including 975 milligrams of EPA and 650 milligrams of DHA. Both EPA (eicosapentanoic acid) and DHA DHA (docosahexaenoic acid) contribute to the beneficial effects of fish oils.
Study participants also underwent brain scans at the start and over the course of the study period. The researchers used MRI to measure brain abnormalities called white matter lesions, which are thought to play a role in the development of cognitive decline and dementia, including Alzheimer’s disease. Increased levels of white matter lesions indicate an increasing breakdown of brain cells. They also looked at the integrity of the white matter directly using a technique called DTI-FA imaging.
The researchers found that across all the participants, taking fish oil did not provide a statistically significant benefit for brain health compared to placebo. But among those who carried the APOE-E4 gene variant, fish oil led to a significant reduction in the breakdown of nerve cells in the brain, as detected with DTI-FA.
“The fact that neuronal integrity breakdown was slowed in people randomized to omega-3 treatment who are also at high risk for Alzheimer’s disease is remarkable and warrants a larger clinical trial in more diverse populations in the future,” said study author Gene Bowman, director of clinical trials and instructor of neurology at the McCance Center for Brain Health at Massachusetts General Hospital and Harvard Medical School. The findings were published in the journal JAMA Network Open.
Lynne Shinto, the study’s lead author and a professor of neurology in the Oregon Health & Science University’s School of Medicine, added that for the general population, “I wouldn’t say you need to take fish oil to prevent dementia,” though “I don’t think it would be harmful.” Though more study is needed, the findings suggest that fish oil supplements could be helpful for those who are at increased genetic risk for developing Alzheimer’s disease.
Other research has shown that fish oils may be good for the brain. One study from 2022, for example, found that people in their 40s and 50s with high levels of omega-3s tended to have a larger hippocampus, a brain region critical for memory. The hippocampus is among the first areas affected by Alzheimer’s disease. Those who had high levels of omega-3 also scored higher on tests of logic and reasoning than their peers with low levels of the healthy fats.
Other research has found that among people who carry the APOE-E4 gene, higher omega-3 levels are associated with greater health of small blood vessels. Impaired small blood vessels in the brain are tied to an earlier onset of symptoms of Alzheimer’s disease and other forms of dementia. Omega-3s also fight inflammation, which may damage organs throughout the body, including the brain.
Greater dietary consumption of fish and other seafood, a staple of the heart-healthy Mediterranean diet, might also reduce the intake of other less healthy fats. For example, a serving of fish might substitute for less healthy choices like a cheeseburger or a slice of pepperoni pizza that are high in artery-clogging saturated fats.
Regardless of your age, it’s never too early or too late to eat foods that may promote better brain health. The easiest way to increase omega-3 intake is to eat more fatty fish, such as salmon, tuna, anchovies or trout. For vegetarians, good plant sources of omega-3 fats are ground flaxseeds, chia seeds and walnuts.
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Eric Schmidt, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Source: Lynne H. Shinto, ND, MPH; Charles F. Murchison, PhD; Lisa C. Silbert, MD, MCR; et al: “Omega-3 PUFA for Secondary Prevention of White Matter Lesions and Neuronal Integrity Breakdown in Older Adults: A Randomized Clinical Trial.” JAMA Network Open, August 1, 2024
