New research is shedding light on a long-standing mystery in Alzheimer’s disease: why women are more likely than men to develop this devastating condition. A recent study suggests that differences in omega-3 fatty acid levels may help explain this disparity, offering a new angle on the biological mechanisms behind cognitive decline. This emerging evidence underscores the importance of understanding sex-based differences in brain health, particularly as they relate to lipid metabolism and Alzheimer’s risk.

Alzheimer’s disease has long been associated with hallmark features like tau tangles and amyloid plaques. However, this study, led by researchers at King's College London, points to another potential culprit—lipid imbalances in the brain. Specifically, the researchers found that women with Alzheimer’s had significantly lower levels of healthy unsaturated fats, such as omega-3 fatty acids, compared to cognitively healthy women. This pattern was not observed in men, suggesting that fatty acid metabolism may influence Alzheimer's disease differently based on sex.

Omega-3 fatty acids are often praised for their role in promoting heart and brain health. Found in fatty fish like salmon and mackerel, as well as in dietary supplements, these unsaturated fats are considered beneficial for reducing inflammation and supporting cognitive function. The new findings raise the possibility that maintaining adequate omega-3 levels could be particularly important for women in reducing Alzheimer’s risk.

The study analyzed lipid profiles from 841 individuals across six European countries, comparing those with Alzheimer's, mild cognitive impairment, and healthy cognition. In women with Alzheimer’s, researchers observed a notable drop in lipoproteins that carry omega fatty acids in the blood. At the same time, these women exhibited higher levels of saturated fatty acids—fats typically considered less healthy. Interestingly, these lipid alterations were not mirrored in men with Alzheimer’s, suggesting a sex-specific biological pathway at play.

“Our study suggests that women should make sure they are getting omega fatty acids in their diet – through fatty fish or via supplements,” said Cristina Legido-Quigley, a pharmaceutical scientist from King's College. While this recommendation aligns with general dietary advice, the researchers emphasize that more evidence is needed. Clinical trials will be essential to determine whether adjusting lipid intake can actually alter the course of Alzheimer’s disease.

The implications of this research are significant. According to a recent Lancet Commission for Dementia, about 7 percent of Alzheimer’s risk is linked to low-density lipoprotein (LDL), which transports cholesterol and fatty acids throughout the body. If LDL and other lipid carriers interact differently in women, this could partly explain why women are nearly twice as likely as men to develop Alzheimer’s. Although women tend to live longer, the higher prevalence of the disease among women cannot be fully attributed to age alone. Even among older adults, men are less likely to develop Alzheimer’s than women of the same age.

One of the more striking aspects of this study is how it reinforces an often-overlooked hypothesis: that fat droplets and lipid metabolism may be key contributors to Alzheimer’s. These elements have historically received less attention than plaques and tangles, but they are also present in the brains of individuals with the disease. This research adds to a growing body of evidence suggesting that the brain’s handling of fats is intricately linked to cognitive health.

What I found particularly compelling is how this study highlights the need for more sex-specific research in neuroscience. Julia Dudley, Head of Research at Alzheimer’s Research UK, who was not involved in the study, pointed out that “further work is needed” to understand the mechanisms behind the observed differences. She added that lifestyle factors, including diet, could play a role, but more investigation is essential to draw definitive conclusions.

Unfortunately, the field has a history of overlooking sex differences. In 2019, only 5 percent of neuroscience and psychiatry studies analyzed the influence of sex, despite clear evidence that men and women may experience brain aging differently. Many clinical trials for Alzheimer’s treatments still fail to examine these differences, which limits our understanding of how the disease progresses and how best to treat it in diverse populations.

Understanding how Alzheimer’s manifests differently in women could pave the way for more personalized treatment strategies. As Dudley noted, this knowledge could help healthcare providers tailor future treatments and health advice more effectively. The hope is that, by identifying specific biological pathways that differ between men and women, researchers can develop targeted interventions that are more effective for each group.

While the findings are promising, the researchers caution against jumping to conclusions. The association between omega-3 levels and Alzheimer’s in women is compelling, but it remains to be seen whether dietary changes can significantly alter disease outcomes. Clinical trials will be crucial in determining whether increasing omega-3 intake can help delay or prevent the onset of Alzheimer’s, particularly in women who may be at higher risk due to lipid imbalances.

As the scientific community continues to investigate the complex interactions between diet, sex, and brain health, studies like this one serve as important reminders of the need for inclusive, nuanced research. By considering the unique biological factors that affect women, we move closer to understanding Alzheimer’s in all its complexity—and, hopefully, to finding more effective ways to combat it.

Read more at sciencealert.com