A Mediterranean diet of nuts, seafood, whole grains and vegetables could lower the risk of dementia by almost a quarter, according to promising early research that could pave the way for new preventive treatments.
The data suggests eating lots of plant-based foods may have a “protective effect” against dementia, regardless of a person’s genetic risk, which the researchers said could form the basis for future public health strategies if further research confirms their findings.
Joint lead author of the study Dr Janice Ranson, a senior research fellow at the University of Exeter, said: “The findings from this large population-based study underscore the long-term brain health benefits of consuming a Mediterranean diet, which is rich in fruits, vegetables, whole grains, and healthy fats.
“The protective effect of this diet against dementia was evident regardless of a person’s genetic risk, and so this is likely to be a beneficial lifestyle choice for people looking to make healthy dietary choices and reduce their risk of dementia.”
The findings, published in the journal BMC Medicine, are based on data from more than 60,000 individuals from the UK Biobank, an online database of medical and lifestyle records from more than half a million Britons.
The researchers scored individuals using two measures for adherence to the Mediterranean diet, and took into account each individual’s genetic risk for dementia. Over the course of nearly a decade, there were 882 cases of dementia, but those who followed a strict Mediterranean diet had a 23% lower risk of developing the condition, compared with those who ate differently.
Dr Oliver Shannon, a lecturer in human nutrition and ageing at Newcastle University and lead author on the study, said finding ways to reduce the risk of developing dementia was a “major priority” for public health. “Dementia impacts the lives of millions of individuals throughout the world, and there are currently limited options for treating this condition,” he said.
Susan Mitchell, head of policy at Alzheimer’s Research UK, agreed that the research was “intriguing” but needed further investigation, which should extended to include people from black, Asian and minority-ethnic backgrounds, particularly since dementia was stigmatised in some communities.
She said there were “no sure-fire ways” to prevent dementia yet. “There is a wealth of evidence that eating a healthy, balanced diet can help reduce the risk of cognitive decline. But the evidence for specific diets is much less clearcut.”
Prof David Curtis from UCL’s Genetics Institute said the study did not reflect the fact that people who ate a Mediterranean diet were more likely to have a generally healthy lifestyle, making it unclear whether the diet itself reduced dementia risk, “although it is plausible that it might do so”.
He added: “It is important to note that the study concerns all forms of dementia, not specifically Alzheimer’s disease. In my opinion if there is an effect of diet then it is more likely to be on cardiovascular health in general and hence to impact dementia due to vascular disease rather than Alzheimer’s disease.”
There are limitations to the results, which are based mainly on people with European ancestry, with further studies needed across a wider range of populations.
Dr Duane Mellor, a dietician and lecturer at Aston University, noted that the food questionnaire used did not reflect British eating habits, for example that potatoes are eaten differently in the UK compared with in the Mediterranean.
Mellor added that it also did not cover the social aspect of eating, which is considered a core feature of the Mediterranean diet, and may have a protective effect against dementia by increasing interactions with people.
• This article was amended on 14 March 2023. An earlier version said that Dr Janice Ranson was a study co-author, rather than joint lead author, omitted her title and said that she was a research fellow rather than a senior research fellow.
