People at the highest genetic risk for Alzheimer’s disease benefit the most from following a Mediterranean-style diet, research has shown.
People with greater risk of developing the condition showed a greater reduction in dementia risk if they followed a Mediterranean diet, compared to those at lower genetic risk.
Researchers from MIT and Harvard explained: “One reason we wanted to study the Mediterranean diet is because it is the only dietary pattern that has been causally linked to cognitive benefits in a randomised trial.
“We wanted to see whether this benefit might be different in people with varying genetic backgrounds, and to examine the role of blood metabolites, the small molecules that reflect how the body processes food and carries out normal functions.”
Alzheimer’s disease and other dementias are some of the most common reasons for cognitive decline in older people. There is known to be a strong genetic component in Alzheimer’s disease, with heritability thought to be up to 80%.
One gene, apolipoprotein E (APOE), carries the greatest genetic risk for developing sporadic Alzheimer’s (the more common type develops in older age and is not directly inherited in a predictable pattern).
People with one copy of the APOE4 variant have a three to four greater chance of developing Alzheimer’s, while those with two copies have a 12-fold higher risk of Alzheimer’s than those without it.
Researchers examined data from 4,215 women from 1989 to 2023 (average age 57 at baseline) and similar data from 1,490 men from 1993 to 2023.
They found that the protective effect of following a Mediterranean-style diet was strongest in the high-risk group with two copies of the APOE4 gene variant. This suggests the diet could help to offset genetic risk.
Study first author and research fellow Yuxi Liu, PhD, said: “These findings suggest that dietary strategies, specifically the Mediterranean diet, could help reduce the risk of cognitive decline and stave off dementia by broadly influencing key metabolic pathways.
“This recommendation applies broadly, but it may be even more important for individuals at a higher genetic risk, such as those carrying two copies of the APOE4 genetic variant.”
Read more in Nature Medicine