\n \u201cOmega-3 supplements as a blunt instrument do not work,\u201d said lead study author Dr. Hussein Yassine, the Volke Endowed Professor of Neurology at the University of Southern California\u2019s Keck School of Medicine in Los Angeles.\n <\/p>\n
\n \u201cEven when we saw high levels of omega-3 in the brains of the treatment group, it did not improve cognition,\u201d said Yassine, who directs Keck\u2019s Center for Personalized Brain Health.\n <\/p>\n
\n What does work? Optimizing your health<\/a> with exercise, stress reduction, quality sleep<\/a> and a plant-based diet<\/a> while adding omega-3s from fatty fish, nuts and seeds, he said.\n <\/p>\n \n \u201cIn the Mediterranean, high omega-3 levels are very strong predictors of good cognition,\u201d Yassine said. \u201cBut people in the Mediterranean are not popping supplements. They\u2019re eating fatty fish, exercising, meeting with friends and living slowly with less stress.\n <\/p>\n \n \u201cIn that context, omega-3s are shining, helping the brain,\u201d he added. \u201cBut if you eat a typical Western diet<\/a> with fast food, don\u2019t exercise, are stressed out all day from work, our study showed having more omega-3 in your brain doesn\u2019t move the needle.\u201d\n <\/p>\n \n After years of public messaging about how fish oil or algae supplements might protect against dementia, it\u2019s time to refine our thinking, said Alzheimer\u2019s prevention researcher Dr. Richard Isaacson, director of research at the Institute for Neurodegenerative Diseases of Florida.\n <\/p>\n \n \u201cOmega-3s are absolutely critical to having optimal brain health, especially for people with the APOE4 gene, which increases the risk of developing Alzheimer\u2019s,\u201d said Isaacson, who was not involved in the new research. \u201cHowever, this study shows they don\u2019t work well in people who have not already optimized their health.\u201d\n <\/p>\n \n CNN reached out to the Global Organization for EPA and DHA Omega-3s, which represents the omega-3 industry, but did not hear back before publication.\n <\/p>\n \n Omega-3 polyunsaturated fatty acids are essential to any animal\u2019s survival. In humans, they lower blood pressure, boost good cholesterol, maintain cell health and reduce the risk<\/a> for cancer, dementia and Alzheimer\u2019s disease.\n <\/p>\n \n Omega-3s are crucial for brain health. Up to 60% of the human brain is made up of lipids, or fats. Some 35% of those fats are omega-3s, experts say<\/a>. Yet the body doesn\u2019t produce omega-3s on its own. Instead, the fatty acids must be obtained from foods such as salmon, herring, mackerel, sardines, walnuts, chia seeds and flaxseeds.\n <\/p>\n \n Many people don\u2019t eat enough fatty fish, seeds and nuts, so supplementation has become widespread. Fish oil supplements provide eicosapentaenoic acid, or EPA, and docosahexaenoic acid, or DHA. The two have different functions \u2014 EPA fights inflammation and supports heart health, while DHA is a core structural building block for the brain, eyes and central nervous system. Vegan supplements contain algal oil made from marine algae, which is also a source of EPA and DHA.\n <\/p>\n \n Chia, hemp and flaxseed oil capsules provide a third type of omega-3 called alpha-linolenic acid, or ALA, an antioxidant with the important job of turning food into energy. It\u2019s also good for the heart \u2014 the risk of dying from heart disease falls by 10% for each gram of ALA eaten per day, according to the Cleveland Clinic<\/a>.\n <\/p>\n \n Raw walnuts are an excellent source. One ounce, or about 14 walnut halves, provides 2.5 grams of ALA, nearly twice the recommended daily amount<\/a>.\n <\/p>\n \n Walnuts also provide magnesium, manganese, copper, vitamin B6 and a host of other nutrients \u2014 a key feature of whole foods that experts say supplements can\u2019t match.\n <\/p>\n \n Wild salmon, for example, contains proteins, vitamins A, D and B-12, and critical minerals such as selenium and potassium \u2014 as well as high-quality omega-3s.\n <\/p>\n \n \u201cWhen you get omega-3s from eating fish, you\u2019re not just getting the single nutrient; you\u2019re getting the whole fish,\u201d Yassine said.\n <\/p>\n \n \u201cBut it has to be part of a healthy lifestyle. If we take that salmon and fry it, it\u2019s not going to count anymore. You can break the omega-3s down by frying the fish, or you can neutralize them by having french fries next to it.\u201d\n <\/p>\n \n The results of the randomized, double-blind, placebo-controlled clinical trial \u2014 considered the gold standard<\/a> of science \u2014 were published Thursday in The Lancet journal ebioMedicine<\/a>.\n <\/p>\n \n The study divided 365 people without dementia between the ages of 55 and 80 into treatment and placebo groups. All had extremely low omega-3 levels and at least one risk factor for dementia, such as obesity, sedentary lifestyle, high blood pressure or cholesterol.\n <\/p>\n \n Nearly 50% had at least one copy of the APOE4 gene \u2014 a group that will be the mostly likely to benefit from supplementation because their brains struggle to process fats efficiently, Isaacson said.\n <\/p>\n \n The treatment group received a high dose omega-3 algae supplement (2,000 milligrams of DHA) each day for 24 months. The control group took a placebo for the same period. Both groups also took a vitamin B complex.\n <\/p>\n \n All participants underwent MRI brain scans, blood draws and cognitive testing at various points throughout the study.\n <\/p>\n \n Testing showed levels of omega-3s in red blood cells climbed from 4.9% to 11% in those taking the supplement. Measures of DHA levels in cerebrospinal fluid, which surrounds the brain, rose by an average of 17% after six months, confirming the omega-3 reached its intended target. The same increases were seen in people with an APOE4 gene, thought to benefit most from supplementation.\n <\/p>\n \n Despite evidence that levels of omega-3 had risen in the brains of people who took the supplement, there were no improvements in cognition or the size of the hippocampus, the brain\u2019s memory center.\n <\/p>\n \n \u201cIn fact, there was no real difference between people taking an omega-3 supplement and those taking a placebo,\u201d Yassine said.\n <\/p>\n \n The results show that omega-3 supplementation is like a \u201cdrop in the ocean\u201d for people who don\u2019t exercise, eat an ultraprocessed food diet and are overweight with signs of chronic disease, Isaacson said.\n <\/p>\n \n \u201cWhat I\u2019m telling my patients is that if a person with one or more copies of the APOE4 genetic variant has low blood levels of omega-3s and is overall healthy, they can still protect against Alzheimer\u2019s and dementia risk by eating fatty fish twice a week and taking a high-quality omega-3 supplement,\u201d he said. \u201cBut if they have an unhealthy lifestyle like the population in this study, an omega-3 supplement just isn\u2019t going to work.\u201d\n <\/p>\n![\"A](\"https:\/\/www.newsbeep.com\/au\/wp-content\/uploads\/2026\/06\/shutterstock-editorial-13939591cc.jpg\")
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