Women are twice as likely as men to develop Alzheimer’s disease — and new research may have uncovered an important clue as to why.

According to the Alzheimer’s Association, an estimated 7.2 million Americans age 65 and older are living with Alzheimer’s. Nearly two-thirds of them are women.

One explanation is that women tend to live longer than men, and age is the greatest risk factor for dementia. But researchers are also investigating biological and genetic differences that may play a role.

Now, a study from King’s College London has found that women with Alzheimer’s have lower levels of unsaturated fats in their system, especially omega-3 fatty acids. Strikingly, the researchers noted “no difference on these lipids in healthy and cognitively impaired men.”

These fats make up about one-third of the brain’s weight, according to The Telegraph. The findings suggest that something unique is happening in the brains of women who develop Alzheimer’s. While scientists don’t yet know why, they advise women to consume more foods rich in omega-3 fatty acids — or consider supplements — as a protective step.

Smart Strategies to Lower Risk

Here are additional ways experts say women can reduce their chances of developing Alzheimer’s:

1. Build Up Cognitive Reserve

Studies show that challenging your brain can help lower dementia risk. Even those who develop Alzheimer’s disease tend to maintain mental function longer if they’ve built strong cognitive reserve. Think of it as a “use it or lose it” function of the brain. The key is variety — learn a new language, take up painting, or volunteer to expand your social circle.

2. Guard Your Mental Health

Barbara Sahakian, a clinical neurologist at the University of Cambridge, says women are more prone to depression than men, and that can raise dementia risk. “Suffering from depression after the age of 75 is strongly associated with dementia,” she explains. Treat depression and anxiety through medication or therapy, and avoid isolation by engaging in daily conversations and social activities.

3. Consider Hormone Replacement Therapy (HRT)

Sahakian notes that more research is needed on how menopause affects the brain. However, since stress is a known risk factor for dementia, managing menopausal symptoms with HRT may help. “Menopause can be stressful for women and since we know that stress is a risk factor for dementia, HRT may alleviate the symptoms, so it’s worth discussing with your doctor,” she says.

4. Exercise Regularly

Even modest amounts of exercise make a big difference. Johns Hopkins researchers found that just 35 minutes of moderate to vigorous activity per week was linked to a 41% lower dementia risk over four years. For women, being fit in midlife is especially protective — those who are very fit are 90% less likely to develop dementia than those who are moderately fit. “It boosts your mood, improves cognition and improves your immune system as well,” says Sahakian.

5. Eat More Eggs and Fatty Fish

The King’s College London findings highlight the importance of diet. Aim for oily fish like salmon or mackerel twice a week to get enough omega-3s. If you choose supplements, make sure they contain both DHA and EPA. Eggs are also valuable since they contain phosphocholine, which helps the body use omega-3s more efficiently.