What We Eat May Affect How Our Brains Age
By Carolina B. Castro1,2,3,4, , Samantha L. Gardener2,5,6 , Manohar L. Garg4, Ralph N. Martins2,4,5 and Hamid R. Sohrabi1,2,3
1 Centre for Healthy Ageing, Health Futures Institute, Murdoch University, Murdoch, WA 6150, Australia;
2 Alzheimer’s Research Australia, Nedlands, WA 6009, Australia;
3 School of Psychology, Murdoch University, Murdoch, WA 6150, Australia;
4 Macquarie Medical School, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia;
5 The UWA Medical School, The University of Western Australia, Perth, WA 6009, Australia;
6 Edith Cowan University, Joondalup, WA 6027, Australia.
Dementia is now the leading cause of death in Australia, and while there is no simple way to prevent dementia, growing research suggests that some of the factors that influence our risk may be within our control. One area attracting increasing attention is diet.
Rather than looking at individual nutrients, researchers are increasingly examining dietary patterns: the combination of foods people regularly eat. This provides a more realistic picture of how diet affects our health and may offer practical lessons for supporting brain health as we age.
One important area of research is brain glucose metabolism. The brain uses glucose as its main source of energy, and reduced glucose metabolism is an early feature of Alzheimer’s disease. These changes can occur years before noticeable symptoms develop and are particularly evident in areas of the brain involved in memory, attention and other cognitive functions.
Research from the Western Australian Memory Study (WAMS) has provided new insight into the relationship between diet and these changes in the brain. The study found that females with greater adherence to a Western dietary pattern experienced a faster decline in brain glucose metabolism over time, particularly in areas of the brain vulnerable to Alzheimer’s disease.
A Western dietary pattern is generally characterised by higher consumption of ultra-processed foods, refined carbohydrates, red and processed meats, added sugars and saturated fats.
By contrast, healthier dietary patterns tend to include more vegetables, fruit, whole grains, legumes, fish and unsaturated fats such as those found in olive oil and nuts.
The findings are important because they suggest that diet may be associated not just with general health or cognitive performance, but with underlying changes in the brain itself.
For people working in dementia care, this highlights the importance of looking at nutrition as part of a broader approach to healthy ageing. It also reinforces the value of focusing on overall diet quality rather than individual nutrients or complicated dietary rules.
Of course, changing the way we eat is not always easy, particularly for older people experiencing cognitive impairment. Changes in appetite, taste and smell, difficulties preparing meals and changing food preferences can all make healthy eating more challenging. Caregivers and aged care staff therefore have an important role to play.
Small, practical changes may be more achievable than major dietary overhauls. Increasing the availability of vegetables, fruit, whole grains and other minimally processed foods, while reducing reliance on ultra-processed foods, can be incorporated into everyday meals and routines.
In residential aged care, the wider food environment also matters. Menu design, nutrition screening, individualised care plans, staff education and enjoyable mealtime environments can all help support better nutrition.
Diet is only one part of maintaining brain health, alongside factors such as physical activity and overall metabolic health. But the emerging evidence provides another reason to consider what we eat as we age.
Healthy eating may not provide a guarantee against dementia, but supporting better dietary patterns could be one practical way to support brain health and healthy ageing.
You can find out more about the potential impacts of diet on dementia risks by subscribing to the Australian Journal of Dementia Care.