Low omega fatty acid levels linked to Alzheimer’s in women

Women with Alzheimer’s disease have omega fatty acid levels up to 20 per cent lower than healthy women, while men show no such pattern, new research shows.

The finding points to sex differences in how the disease develops and affects the body, prompting researchers to advise women to ensure enough omega fatty acids through diet.

Blood samples from 306 people with Alzheimer’s, 165 with mild cognitive impairment and 370 cognitively healthy individuals revealed the gender divide.

The research was carried out at King’s College London, with results published in the Alzheimer’s & Dementia journal.

Women with Alzheimer’s had higher levels of saturated lipids – fatty compounds generally considered unhealthy – and lower levels of unsaturated lipids, including omega fatty acids, compared to cognitively healthy women. This pattern was not seen in men.

Dr Cristina Legido-Quigley, a senior author on the study, said: “The difference between the sexes was the most shocking and unexpected finding.

“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.”

Alzheimer’s is twice as common in women as in men.

Factors such as women’s longer lifespan, hormonal differences, immune responses and educational opportunities may all contribute.

If liver or metabolic changes are behind the lower omega levels, fewer of these essential fatty acids would reach women’s brains.

Diets rich in omega-3 fatty acids, such as the Mediterranean diet, have long been linked with heart and brain health.

A 2022 study found middle-aged people with higher blood omega-3 levels had better cognitive function.

However, trials giving older people omega-3 supplements have not improved cognition in those already diagnosed with dementia.

Legido-Quigley wants clinical trials to test whether supplements can delay Alzheimer’s specifically in women with low unsaturated fatty acid levels, adding that the drop may start to appear when women reach their 50s.

Three essential omega-3 fatty acids exist: ALA, found in chia seeds, flaxseed and walnuts; and DHA and EPA, mainly from fish.

The NHS recommends two 140g portions of fish a week, including one oily fish.

Dr Julia Dudley at Alzheimer’s Research UK, which co-funded the study, said more work was needed to understand the mechanisms behind the sex difference.

She said: “Understanding how the disease works differently in women could help doctors tailor future treatments and health advice.”