Mediterranean Diet Linked to Lower Depression Risk in Older Women, Study Finds

Of the 798 older adults enrolled in an Italian cohort study, roughly one in five reported depressive symptoms. The split by sex was stark: 28% of the 473 women, against 8% of the 325 men. That gap is the backdrop to a new paper in the British Journal of Nutrition, which asks whether what older people eat is linked to how they feel.

The data come from the NutBrain cohort, short for Nutrition, Gut Microbiota, and Brain Aging, a population-based group of community-dwelling older people. The work ran from October 2019 to January 2023. The mean age was 73, and 60% of participants were between 65 and 74. About 66% were married and living with others, and 50% were considered underprivileged. Researchers used a food frequency questionnaire to score adherence to the Mediterranean diet, producing a Mediterranean diet score, and paired it with a depression measurement scale.

The context is a heavy one. About 5% of the world's population has depression, and it ranks among the leading causes of disability. Prevalence rises with age, affecting a third of older people. Women face higher risk from adulthood, and it climbs further after 60. In Italy, 10% of people over 65 report depressive symptoms, and up to 14% of women aged 85 and over experience depression. Because biological, psychological, social, and environmental factors all play a part, diet is treated as one modifiable piece of the picture.

Those in the top third of diet scores were 55% less likely to report depressive symptoms. Among women alone, the reduction was 60%. Each one-point rise in the score cut the risk by 16% overall and 18% in women. In men, the effect was not significant. About 33% of men adhered to the diet, compared with 25% of women.

Fish stood out. High fish consumption was tied to a 44% lower risk across the cohort, and 56% lower among women. Each additional gram of fish lowered the likelihood of depression by 2% overall and in women, but not in men. Eating three or more weekly servings of shellfish, sole, trout, sea bream, cod, hake, or sea bass was linked to a 62% reduction overall. Women eating two to three servings of these fish a week had a 43% lower risk, and those eating three or more had a 70% lower risk than women eating two or fewer. Again, no such pattern appeared in men.

Other foods mattered too. Women whose diets had a high ratio of monounsaturated to saturated fat were 42% less likely to report symptoms. Across both sexes, nut and fruit consumption was associated with reductions of 82% and 42%, respectively. Among women, depressive symptoms were also more common in those who were unmarried, lived alone, took more medications, considered themselves sicker, or ate less fish, vegetables, and healthy fats relative to saturated fat. Among men, the only difference between those with and without depression was that those with depression used significantly more medications.

The authors offer possible explanations for the fish finding: less inflammation, regulation of hypothalamic and pituitary hormones, lower oxidative stress, gut microbiota differences, and other metabolic pathways. For the stronger effect in women, they point to the higher prevalence of vitamin D deficiency among women and to omega-3 fatty acids altering brain cell membranes. They stress that further research is needed to confirm these ideas.

The study is observational, so it cannot prove that diet changes depression, and participant selection may carry biases. The authors note, however, that the cohort represented the older community in each locality. They conclude that public health efforts to promote healthy eating in older people are likely to be productive while studies continue to probe the biology.