Research shows that brain health is promoted by maintaining our weight in a healthy range.

 

A special thanks to this month's contributors. Carol Wham is a dietitian and professor of public health nutrition at Massey University in Auckland. Joke van Staveren and Jane Hobson are physiotherapists with the Canterbury District Health Board in Christchurch.

Being under-weight
  • While being underweight has been associated with higher rates of dementia, this is complicated because people with early dementia can often report changes in appetite and diet.
  • Becoming under-weight can be a special problem for people living with dementia because the illness can cause impaired appetite, taste and smell as well as difficulties with planning meals, shopping for food, cooking, and eating.  Food energy requirements may also be higher as sometimes dementia illnesses give rise to much-increased physical activity, such as through restlessness. 
  • When being under-weight is a problem, we need to consume more energy from foods and drinks by eating small amounts often, to build our body up more than we burn off through physical activity.
  • A medical assessment of any underlying medical causes and dietitian advice for ways to increase healthy calorie intake can be helpful.  The problem may be simple to solve such as eating together with other people, fixing some ill-fitting dentures, altering a medication that is lowering appetite, arranging pre-prepared meals from family or a service such as “Meals on Wheels”, or providing a high-energy snacks and drinks.
A healthy weight
  • On the other hand, over-eating and drinking too much alcohol can result from our modern lifestyle with limited opportunity for physical activity.  This means that maintaining a healthy weight can be a challenge.  Two thirds of adults were found to be overweight (35.3%) or obese (30.9%) in the latest New Zealand Health Survey 2019/20. 
  • To check whether you or someone you care about has a healthy weight compared to height, use the Heart Foundation body mass index (BMI) calculator. 
How might high weight increase the risk of dementia?
  • A large overview of studies found that being obese (BMI ≥30) was associated with late-life dementia.
  • As body weight increases it seems blood flow and activity in the brain decrease, which is associated with developing Alzheimers disease. 
  • High BMI can increase your blood pressure and the risk of type 2 diabetes,. These factors are both linked to a higher risk of Alzheimer's disease and vascular dementia.
Losing weight
  • Losing even a small amount of weight when we start from a position of being over-weight can improve our quality of life and make us more mobile and more energetic. 
  • Avoid fad diets; they don’t work long term. If a diet sounds too good to be true, the chances are it is! Losing weight is not achieved via a ‘quick fix’ solution.
  • One way we can think about this is to aim to improve our diet step by step every few months rather than aim to completely overhaul it in one go.  Here’s a guide to following a heart-healthy way of eating in the right amounts from the NZ Heart Foundation.
  • It’s about consuming less energy from foods and drinks than we burn off through physical activity.  The main ways to do this are to choose healthier foods, to eat a bit less of most things (except all those colourful non-starchy vegetables and fruit), and to move more. The best plan is to set realistic goals we can stick to.  
  • The May calendar tip will be about physical activity.