It’s estimated that there are currently 50 million people living with dementia globally. Major risk factors for dementia include age, genetics and family history. For example, people who have a gene called APOE4 are at much higher risk of developing Alzheimer’s disease – the most common form of dementia. As explained by Prof. Jennie Brand-Miller in FOOD FOR THOUGHT, there’s also increasing evidence for a link between diabetes and dementia, particularly type 2 diabetes. In fact, some researchers have described Alzheimer’s disease as type 3 diabetes.
The good news is that there are many things you can do to reduce your risk. In fact, evidence suggests that at least half of the risk of dementia can be attributed to lifestyle factors including diet, exercise and smoking. What’s more, studies show that people at higher risk of Alzheimer’s disease due to having the ApoE4 genotype may benefit even more from making lifestyle changes.
This was demonstrated in a study published last year in the Journal of the American Medical Association which followed more than 196,000 adults aged 60 year or older for around 8 years. They were divided into low, intermediate or high-risk categories, based on measurement of their genetic risk. The researchers then gave participants a healthy lifestyle score based on whether they smoked, drank alcohol only in moderation, ate a healthy diet and were physically active, dividing them into favourable, intermediate, and unfavourable lifestyle groups. Not surprisingly, those at higher genetic risk were more likely to develop dementia. However, the study found that in those at high genetic risk, following a favourable lifestyle reduced the risk of developing dementia by 32% compared to an unfavourable lifestyle.
In this study, a healthy diet was classified as one that included higher intakes of fruit, vegetables, wholegrains and fish but lower intakes of processed meats, red meats and refined grains. Other research has shown that a higher intake of saturated fat can increase the risk of dementia, particularly in those with the APOE4 gene, while unsaturated fat intake appears to be protective. However, the types of carbohydrate (starches and sugars) in our diet may also play a role. A 2017 study found that in older adults with normal cognitive function (meaning they didn’t have dementia), those consuming a high glycaemic load diet had higher levels of amyloid plaques in their brain. Amyloid plaques are thought to play a role in the development of Alzheimer’s disease. A previous study found an association between the glycaemic load of the diet, blood glucose levels and cognitive performance.
- Association of Lifestyle and Genetic Risk With Incidence of Dementia.
- A high-glycemic diet is associated with cerebral amyloid burden in cognitively normal older adults.
- Blood glucose, diet-based glycemic load and cognitive aging among dementia-free older adults.
Kate Marsh is an is an Advanced Accredited Practising Dietitian, Credentialled Diabetes Educator and health and medical writer with a particular interest in plant-based eating and the dietary management of diabetes and polycystic ovary syndrome (PCOS).
Contact: Via her website www.drkatemarsh.com.au.