More signs found that Mediterranean eating reduces brain disease risk

Greek yoghurt, fresh tomatoes and greens, fish so fresh it drips seawater, little by way of saturated fats or processed food and of course everything cooked in olive oil: a "Mediterranean” diet has long been lauded for helping prevent or curb diabetes, high blood pressure, heart disease and obesity.

In recent years, some indications published have suggested such a diet could also slow cognitive decline. A new British Medical Journal study carried out by a multinational team of nutritionists and doctors has found possibly the clearest indications to date that eating Mediterranean can be “favourably linked to lower risk of neurodegenerative diseases".

Led by Changzheng Yuan of Zhejiang University School of Medicine, the researchers assessed health information for 1,647 “middle-aged and older” people over a median follow-up period of around 12 years.

The data suggest “greater adherence” to a Mediterranean diet “was associated with slower decline in total grey matter volume", according to the team, which included researchers from Harvard T.H. Chan School of Public Health, Boston University School of Medicine, Harbin Institute of Technology and the University of Edinburgh.

The scientists say that while prior research “implied” the diet's "beneficial associations with brain imaging markers", any association with “long-term brain structural changes remained unclear".

In a study covering around 92,000 people and published by the American Medical Association in 2024, a Harvard T.H. Chan School of Public Health researchers say they found higher olive oil intake to be “associated with a lower risk of dementia-related mortality, irrespective of diet quality".

The latest BMJ-published findings suggest that people who stick to a Mediterranean diet show “slower signs of brain ageing", according to Jacqui Hanley of Alzheimer’s Research UK.

Hanley cautions that the study "cannot prove a direct protective effect and did not measure impacts on memory or thinking” and warns that “more long term studies in diverse groups are still needed to untangle the role of diet, genetics and other factors".

But the latest research “add[s] to growing indications that eating a balanced diet, staying active and taking other healthy steps may support our brain health as we age,” she says.