Scientists learn why Alzheimer's is more common in women

A new study reports that women with Alzheimer’s have fewer unsaturated lipids and more saturated ones in their blood. The same pattern did not show up in men with the disease.

Almost two thirds of Americans living with Alzheimer’s are women. That gap has puzzled researchers for years.

Lipids and Alzheimer’s disease

Dr. Cristina Legido-Quigley of King’s College London led the research. Her team analyzed blood from adults who were cognitively healthy, had mild cognitive impairment, or had Alzheimer’s.

The scientists used lipidomics, which is a detailed chemical scan of fat molecules, to quantify 268 individual lipids. They then compared patterns by sex to see whether specific lipids tracked with memory loss.

The team focused on families of lipids that carry or build cell membranes, including phospholipids and triglycerides. Finally, they related lipid patterns to common Alzheimer’s biomarkers and cognitive test scores.

Women with Alzheimer’s showed lower levels of lipids rich in omega fatty acids, which are highly unsaturated. At the same time, women with the disease had higher levels of more saturated lipids.

The shift was not detected in men when compared with healthy male peers. That split points to a biological difference tied to sex rather than to age alone.

Why lipids might matter

Unsaturated lipids help keep brain cell membranes flexible and support synapses. When those lipids dip, cellular signaling and transport can suffer.

The study also connected lipid changes to measures of brain injury and inflammation. Lower unsaturated lipids tracked with worse cognitive scores in women, which adds clinical weight to the findings.

The team ran the analysis separately for women and men. Associations between lipid profiles and Alzheimer’s were concentrated in women and largely absent in men.

The results suggest that risk pathways may look different across sexes. They also show why sex specific analyses are not optional in brain research.

What this does not prove

Observational data cannot prove cause and effect. The authors used statistical tools to probe whether cholesterol related pathways explained the results, and the core signal in women persisted in several tests.

“There’s an indication that having less of these compounds could be causal in Alzheimer’s, but we need a clinical trial to confirm that,” said Dr. Legido-Quigley.

She explained that the next step is to see if changing lipid intake can alter the course of the disease.

Alzheimer’s, lipids, and diet

The data point toward omega fatty acids as a candidate to watch. They sit inside many of the unsaturated lipids that were reduced in affected women.

“Our study suggests that women should make sure they are getting omega fatty acids in their diet, through fatty fish or via supplements,” said the doctor. She also stressed that trials are needed to test whether diet can alter disease risk.

Lipids are types of fats in the body that store energy, form cell walls, and help cells communicate. Some lipids are simple, while others are more complex and act as building blocks for cells.

Phospholipids make up most of the cell wall and control what moves in and out. Triglycerides mainly act as storage fats, carrying fatty acids through the blood when the body needs fuel.

What the statistics add up to

The analysis covered hundreds of lipids with precise chemical formulas. It found that larger, highly unsaturated lipids were consistently lower in women with Alzheimer’s.

More saturated and monounsaturated phospholipids were higher in women with the disease. That combination links both the type and the degree of unsaturation to cognitive status.

The researchers assessed whether common blood measures, such as cholesterol and low density lipoprotein, could explain the results.

For several lipid groups, the sex specific signal remained even after those markers were considered in the models.

Genes can also affect how the body manages fats. The study considered APOE ε4, a common risk gene for Alzheimer’s, to separate genetic effects from the fat changes linked to the disease.

Focus of future studies

These results do not justify medical claims about supplements. They do justify paying attention to sex in both diagnosis and trial design.

Experts note that learning how the disease affects women differently could help doctors design more personalized treatments and health advice, leading to faster progress.

Future studies will test whether adding omega rich foods or supplements changes women’s lipid profiles before symptoms begin. They will also track whether those changes align with slower cognitive decline.

Diverse cohorts will matter. The current data are strongest in European participants, so broader sampling will show how universal these patterns are.

Lipids, Alzheimer’s, and future health

The researchers compared fats in the blood with proteins that show brain damage or stress. These proteins, called neurofilament light chain and glial fibrillary acidic protein, are often used to track Alzheimer’s.

In women, higher levels of certain healthy unsaturated fats were tied to better thinking test scores. This connects changes in fats more directly to memory and brain health.

It is unusual to see an analysis that goes down to individual lipid molecules while keeping a large human cohort. It is also rare to see sex stratified statistics carried through to the end.

The takeaway is clear. In women with Alzheimer’s, unsaturated fats are consistently lower, and future clinical trials will show whether addressing this shortage can make a difference.

The study is published in the Journal of the Alzheimer’s Association.

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