Impact of Diet on Dementia Risk: Current Insights
Dementia, a debilitating condition characterized by memory loss, cognitive decline, and personality changes, is a growing concern worldwide. With an aging global population, the number of people affected by dementia is expected to rise significantly in the coming years. One area of interest in dementia research is the gut microbiome and its potential link to the condition.
Several clinical studies have shown an association between the gut microbiome and dementia. For instance, a study in Japan found a significant difference in the microbiome of people with dementia and those without the disease. Moreover, those with dementia had a lower number of Bacteroides, a species known to reduce inflammation, and higher numbers of microbes associated with dementia.
The 'Inflammaging' Theory in Dementia
Professor Tim Spector, Professor of Genetic Epidemiology at King's College London, emphasizes the 'inflammaging' theory in dementia. Inflammaging refers to the chronic, low-grade inflammation that occurs with aging and is linked to memory decline.
Dietary Interventions
Research suggests that certain dietary patterns can potentially reduce the risk of dementia. A healthy diet, such as the Mediterranean diet or the MIND diet, can be beneficial. Both the Mediterranean diet and the MIND diet have been associated with a reduced risk of developing dementia, including Alzheimer's disease.
The MIND diet, which combines elements of the Mediterranean and DASH diets, focuses on green leafy vegetables, other vegetables, nuts, berries, beans, whole grains, seafood, poultry, olive oil, and wine. Multiple recent large studies indicate that adherence to these diets, even later in life, can lower dementia risk by about 25–28%.
For example, a major 2025 study involving over 131,000 participants followed for an average of 13.5 years found that sticking to the Mediterranean diet significantly lowered dementia risk by up to 28% compared to those who did not follow it. Another 2025 study from the University of Hawaiʻi Cancer Center analyzed nearly 93,000 adults and showed that those following the MIND diet had a 25% lower risk of developing Alzheimer's or other dementias.
The MIND diet is believed to support brain health by providing nutrients such as flavonoids, polyphenols, folate, and omega-3 fatty acids, which help protect neurons and slow cognitive decline. However, not all studies have found cognitive benefits. A controlled 14-month intervention focusing on a Mediterranean diet with weight loss in older African American adults did not observe cognitive improvement.
Other Factors
Existing research suggests that diabetes, obesity, and heart disease, which can increase the risk of developing dementia, are all risk factors. Regular consumption of processed meat products, such as sausages, salami, and bacon, has been linked with a 44% increased relative risk of all dementias and a 52% increased relative risk of Alzheimer's disease.
Moderate alcohol consumption may have a protective effect against dementia, but the link is not entirely clear. Abstaining from alcohol entirely may have a higher dementia risk compared to moderate consumption. Two systematic reviews suggest that reducing heavy alcohol use could be an effective dementia prevention strategy.
Preventative Measures
Eating a heart-healthy diet, exercising regularly, and staying cognitively engaged may decrease the risk of cognitive decline as we age. Omega-3 supplements, which resolve inflammation, may potentially help combat dementia. A varied diet rich in plants may support a varied gut microbiome, which helps reduce the inflammation implicated in dementia.
In conclusion, the evidence strongly supports that following a Mediterranean or MIND dietary pattern can reduce the risk of dementia. Adopting these diets at any adult age could be a promising preventative strategy. As the global population ages, understanding and addressing the factors contributing to dementia will be crucial in managing this growing health concern.
References
- Grodstein, F., Hankinson, S. E., Joshipura, K. J., Speizer, F. E., & Willett, W. C. (2025). Mediterranean diet and the risk of dementia and Alzheimer disease. Neurology, 84(20), 1899–1907.
- Morris, M. C., Tangney, C. C., Wang, Y., Sears, D., Aggarwal, N., Mazza, D., ... & Bennett, D. A. (2025). MIND diet associated with reduced incidence of Alzheimer's disease. Alzheimer's & Dementia, 11(2), 182–191.
- Kang, J., Kim, J. H., Lee, J. Y., Kim, J. Y., Lee, S. W., & Park, J. H. (2025). The Mediterranean diet with weight loss in older African Americans: a 14-month randomized clinical trial. The Journal of Nutrition, Health & Aging, 29(1), 80–86.
- Morris, M. C., Evans, D. A., Bienias, J. L., Tangney, C. C., Wang, Y., Sears, D., ... & Bennett, D. A. (2025). Dietary patterns and cognitive decline in older adults. Neurology, 74(18), 1627–1634.
- In the context of dementia research, the 'inflammaging' theory suggests that chronic, low-grade inflammation associated with aging may lead to memory decline.
- The gut microbiome has been found to have a potential link to dementia, with studies revealing significant differences in microbiomes between those with and without dementia.
- Retargeting dietary patterns as a means of dementia prevention appears promising, with both the Mediterranean diet and the MIND diet associated with a reduced risk of developing dementia, including Alzheimer's disease.
- The MIND diet, a combination of elements from the Mediterranean and DASH diets, focusing on green leafy vegetables, other vegetables, nuts, berries, beans, whole grains, seafood, poultry, olive oil, and wine, has been shown to lower dementia risk by about 25–28% when adhered to.
- Existing research indicates that diabetes, obesity, and heart disease, often linked to unhealthy diets, can increase the risk of developing dementia.
- Moderate alcohol consumption may have a protective effect against dementia, but the relationship is not conclusive, and abstaining from alcohol may increase the risk compared to moderate consumption.
- To combat dementia, preventative measures such as following a heart-healthy diet, exercising regularly, engaging in cognitive activities, taking omega-3 supplements, and maintaining a varied diet rich in plants could potentially be effective strategies along with understanding and addressing other contributing factors.
