Writing in the journal Clinical Nutrition, an international group of researchers reviewed the records of more than 217,000 adults from the UK Biobank, a large-scale database that stores extensive personal and medical data from volunteers to facilitate research on numerous health conditions and diseases.
The scientists who conducted the study showed that objectively measured omega-3 status is linked to an up-to 40% lower risk of dementia diagnosed before age 65.
“Most prior research has focused on older populations,” Aleix Sala‑Vila, PhD, lead author of the study, said in a statement. “Our findings strongly suggest that omega-3 intake earlier in midlife may play a meaningful role in brain health decades before dementia typically appears.”
The protective association was documented not only for DHA—the most common omega-3 fatty acid in the brain—but was even stronger for non-DHA omega-3 fatty acids. The study authors also noted it is important to consider the full range of omega-3s rather than focusing on DHA alone.
The study was carried out by researchers from the Fatty Acid Research Institute (South Dakota), Hospital del Mar Research Institute (Spain), Instituto de Salud Carlos III (Spain), University of Illinois-Chicago and the University of South Dakota.
A plausible, low-cost strategy
Mostly supplied by fatty fish and fish oils, omega-3 fatty acids may hold promise in preserving cognition. Preclinical studies show the fatty acids are likely to increase neurogenesis and regulate inflammation and neuroinflammation. Omega-3 fatty acids may also be associated with a lower risk of late-onset dementia.
“We were not necessarily expecting to find a relationship with omega-3 levels,” said Bill Harris, PhD, president of the Fatty Acid Research Institute (FARI) and investigator on the paper. “The fact that we did was exciting because it suggests—certainly does not prove—that getting your omega-3 levels high and keeping them there throughout at least adulthood could forestall both early and late onset dementia.”
According to the study, EOD is diagnosed before the age of 65, with 370,000 new cases appearing globally each year. EOD incidents may be associated with a person’s environment and lifestyle, but research on those areas is scarce. Some studies show consuming a Mediterranean-DASH diet may decrease EOD risk.
Of the patient data included in the large-scale analysis, the researchers studied omega-3 biomarkers and incidence of EOD. They also examined the percentage exposure to total omega-3s, DHA and non-DHA omega-3s by focusing on directly measured levels of plasma. Findings indicated a 35% to 40% reduced risk of EOD when omega-3s were consumed. Ultimately, the study followed adults aged 40 to 64 for an average of 8.3 years and identified 325 cases of EOD.
“The number of UK Biobank participants with available baseline fatty acid data allowed us to examine the association with adequate statistical power in this under-explored population segment,” the researchers wrote. “We observed inverse associations in EOD, similarly to what has been observed in late-onset dementia.”
Omega-3 levels can be safely and effectively increased through diet and supplementation. The researchers suggest this represents a plausible, low-cost strategy that could help reduce the burden of early-onset dementia.
“When a safe, accessible lifestyle factor is consistently associated with lower disease risk, it deserves serious consideration as part of a broader prevention strategy,” Dr. Sala-Vila said.
Source: Clinical Nutrition. doi: 10.1016/j.clnu.2025.106559. “Blood omega-3 is inversely related to risk of early-onset dementia”. Authors: Aleix Sala-Vila et al.
