The Nutrition Society Paper of the Month for July is from Proceedings of the Nutrition Society and is entitled ‘Diet, nutrition and the ageing brain: current evidence and new directions’ by authors: Katie Moore, Catherine F. Hughes, Mary Ward, Leane Hoey and Helene McNulty.
Worldwide populations are ageing and mental health is considered to be one of the greatest global challenges. Advancements in the treatments of these mental health conditions have been somewhat limited, consequently there is an urgent need to identify modifiable factors for targeted interventions to promote better brain health in our ageing populations.Emerging evidence supports a role for certain dietary factors in brain health, opening up new potential avenues for prevention of dementia and depression in older adults. Within our review, we explored the influence of ageing on brain health and the emerging evidence linking diet and specific nutrients with cognitive function and depression in older people.
Evidence linking certain dietary patterns, particularly the Mediterranean diet, with a reduced risk of dementia and depression is accumulating however further well-designed randomised controlled trials are required to more fully investigate its role. Specific dietary components such as n-3 PUFA, polyphenols, vitamin D and B-vitamins have also been investigated in relation to brain health. The strength of the evidence for these particular components varies but the totality of evidence is strongest for folate and the metabolically related B-vitamins. Randomised trials have shown that B-vitamin supplementation reduces the rate of cognitive decline and may reduce the risk of depression in ageing.
We also considered the role of novel imaging technologies and their application in nutrition research. The use of these technologies in combination with questionnaire assessments can provide an objective and highly robust means of assessing brain function and activity. The literature suggests that studies incorporating new technologies, such as MRI and magnetoencephalography, offer much promise in establishing effective nutrition interventions that could reduce the risk of cognitive and mental disorders.
In summary, nutrition is a modifiable factor that has important roles in preserving cognition and reducing the risk of late-life depression. Emerging evidence in this area implicates subclinical deficiencies of certain nutrients in cognitive decline and depression in older adults, with the strongest evidence coming from B-vitamin randomised trials that have also incorporated brain-imaging outcomes. Future well-designed studies incorporating imaging technologies are required to provide more robust evidence, which could influence policy, ultimately reducing the burden on the health service and improving quality of life for older adults.