Feature articles

Diet and dementia

Ngaire Hobbins is an Accredited Practising Dietitian and authority on nutrition, ageing and brain health. She offers sensible, practical guidance on eating to help the body meet the challenges of later age, prevent premature physical and cognitive decline and reduce the risk of dementia. Ngaire is the author of three books, speaks widely to both professional audiences and community groups, is a regular contributor on radio and in print media.

How big a problem is dementia in Australia and New Zealand? 
Approximately 10% of people over 65 and 30% over 85 live with dementia. But that means 90% over 65 and 70% over 85 don’t – and there are things that can be done to help reduce the risk of developing dementia as we age.

What is the evidence that diet plays a role in the development of dementia?
There is growing evidence that diet is an important lifestyle factor influencing brain health as we age. The DASH and Mediterranean diets have been found to be associated with reduced risk and intervention studies are now testing these dietary patterns. As well as healthy eating, maintaining physical activity throughout life, staying socially connected and learning new things are also protective.

What dietary components or patterns are protective?
It comes down to trying to eat foods as often as possible that have been through minimal change since they came from the tree, the ground, the farm, river or ocean. This can help reduce the chronic inflammation thought to contribute to changes in the brain which are considered to be part of the development of dementia. As well, eating plenty of vegetables, legumes, fruits, nuts and seeds of different colours contributes useful, cell-protective antioxidants, while eating oily fish and good oils (from olives, nuts and seeds) adds important Omega 3 fats.  

What dietary components or patterns are risky?
Opposite to the above. Eating more food that has undergone many steps in production ('highly processed' in everyday terms) seems to add to your risk. As people age beyond their mid 60s, it’s also increasingly important to maintain body muscle to help support brain health: that means combining regular exercise with ensuring there's a good source of protein at each meal. Therefore sedentary lifestyles, the 'tea and toast' routine and unintentional weight loss should be avoided.

Is there any evidence that sugar contributes to the risk of dementia?
It is not sugar itself that is the issue, but eating a large number of foods to which sugar has been added during processing may increase risk. The ideal diet to reduce dementia risk has good protein, plenty of vegetables, wholegrains, legumes, nuts, seeds and good oils: occasionally adding sweetness from sugar in recipes using these foods is not likely to create problems.

What do you believe is the biggest nutrition issue facing our ageing population?
As people move into older age, things are quite different from a nutrition point of view than they are for younger adults. Appetite often declines so food intake can fall too low to provide adequate nutrients to support the body and brain; and weight loss becomes more of a concern than weight gain. Losing weight at later age without a good exercise regime to support muscle maintenance, will cause muscle loss which ultimately impacts the health of the body and the brain. The advantage older people have now is that they have lived lives eating mostly fresh, unprocessed foods which is often locally sourced. What remains is the challenge to stay active, eat a good variety of foods, avoid unintentional weight loss and keep the appetite going. For the frail elderly with dwindling appetites, sweet treat foods (often frowned upon for younger adults and children) can be very useful to prop up energy intakes. 

NEXT: Global causes of death 

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