As there is still no cure for dementia, reducing our risk of cognitive decline in later life through dementia prevention strategies becomes increasingly important. Dementia is a complex disease and can be influenced by a number of risk factors, some of which are modifiable (such as diet and lifestyle) and some cannot be modified (age and genetics). Those that are modifiable pose the greatest possibility for dementia prevention.
Recently, researchers have found that up to 40% of dementia cases worldwide are linked to modifiable risk factors, many of which are nutrition and lifestyle dependent such as depression, obesity, high blood pressure and type 2 diabetes. These risk factors can be prevented, making these findings extremely promising especially when dementia has been historically viewed as an inevitable, and unavoidable, part of the ageing process. But, why is this particularly important for those living in low- and middle-income countries (LMIC’s)?
Globally, there are approximately 50 million people living with dementia. It is estimated that this number could nearly triple by 2050, rising significantly in LMICs where around two-thirds of people with dementia currently live. Recently some high-income countries have seen a reduction in the proportion of people with dementia, mainly due to improvements in health and social care, nutrition and lifestyle behavioural changes. It is therefore important to understand how this might be feasible in a LMIC context, and how these countries can be supported to implement dementia prevention initiatives to reduce the disease burden in these settings.
The role of diet in dementia prevention
Eating a healthy, balanced diet and limiting consumption of foods high in saturated fat, refined sugar and salt have long been established as beneficial for health. Researchers are investigating how certain foods and dietary patterns can have a role in prevention of cognitive decline. Accumulating evidence supports the role of the Mediterranean diet in improving cognitive function; a diet rich in olive oil, oily fish, fruit, vegetables, wholegrains and low in red meat and confectionary. Studies have shown that greater adherence to a Mediterranean diet is associated with reduced dementia risk.
Research into diet and dementia is constantly evolving. Researchers are working to better understand how specific dietary components can influence cognition, how these foods affect brain health when consumed together and how to tailor dietary advice to specific countries, cultures and settings. When we think about making changes to our diets and lifestyles, we know that “one size does not necessarily fit all”. It is important to understand the food cultures and available resources of different countries in order to provide tailored, needs-specific dietary advice and support.
Case study: Spotlight on Malaysia
The Global Health Dementia Prevention and Enhanced Care project (DePEC) is funded by the National Institute for Health Research, UK and is led by researchers from Newcastle University, UK together with Monash University, Malaysia. The research project includes a work stream that aims to understand how Malaysian adults at risk of cognitive decline can make changes to their diet. Malaysia is a diverse country; the myriad of ethnicities within the population make the Malaysian food scene unique with Malay, Indian and Chinese cuisines traditionally popular. However, Malaysia is experiencing a rapid economic growth and a shift in food consumption. Changes in individual eating and lifestyle patterns influenced by Westernised dietary practices have been linked to significant increases in the prevalence of chronic diseases. The Global Burden of Disease Study in 2019 highlighted that the key dietary risks in South-East Asia are related to a high sodium (salt) intake and low intakes of fruit and vegetables. Consequently, the Ministry of Health in Malaysia has taken action towards reducing salt intake, introducing a five-year Salt Reduction Strategy to Prevent and Control Non-Communicable Disease for Malaysia. This is an important stepping stone to help improve the health of the nation and reduce the burden of disease in Malaysia.
Effective public health interventions for the prevention of dementia are challenging in countries like Malaysia where limited social and healthcare resources are unable to meet the growing demands of ageing populations. A recent systematic review of nutritional interventions for dementia prevention in South-East Asia showed some evidence to support the role of nutritional supplements, particularly B vitamins and fatty acids, as promising strategies to reduce the risk of cognitive decline. However, more research is needed to identify which dietary interventions are most feasible and effective to decrease dementia in these settings. The DePEC project includes a dietary intervention study among middle-aged and older adults in Malaysia who have high blood pressure (and therefore are at increased risk of cognitive decline) and aims to understand their ability to make changes to their diet. Participants received education on how to reduce salt and eat more green leafy vegetables, and the study will provide important feedback on the acceptability and implementation of this type of intervention. This will help to understand the challenges and opportunities faced by at-risk middle-aged and older individuals when changing their dietary habits in this LMIC setting and allow the intervention to be tailored for a larger, follow-on trial to continue this research. Although impacted by COVID-19, the DePEC study is currently ongoing and we hope to publish the findings later this year.
The future for dementia prevention research is bright and I am excited for what this future will bring, with new avenues constantly being explored and some large-scale diet and lifestyle studies currently underway. Now is the time to think about investing in dementia prevention, prioritising research efforts and to consider what we can do to maintain our brain health as we age.
This research was funded by the National Institute for Health Research (NIHR) (16/137/62 – Dementia Prevention and Enhanced Care (DePEC), Newcastle University, United Kingdom), using UK aid from the UK Government to support global health research. The views expressed in this blog are those of the author(s) and not necessarily those of the NIHR or the UK Department of Health and Social Care.