What do fizzy drinks and TV watching have to do with brain health?
We often talk about brain health and dementia risk on this blog, and how it’s a complex mix of age, our genes and the lifestyles we lead. It’s also a highly active area of research, with scientists across the globe working to understand why some people develop dementia and others don’t.
This week at the Alzheimer’s Association International Conference (AAIC) 2018 in Chicago, researchers are presenting some of the latest research in this area, and there is a theme emerging. Many studies are now looking at lifestyle factors in early adulthood and midlife, to see how they are related to brain health and dementia in later life.
Here is a snapshot of some of the research developments presented so far:
What’s good for your heart is good for your brain. This old saying was backed up by more research this week after a new study looked at how heart health risk affect the size of a person’s brain – a indicator of healthy brain ageing. Scientists found that risk factors for heart disease in midlife, rather than later life, were most strongly linked to smaller brain size in older age. This suggests that it is never too early to start looking after your heart health, and have knock-on benefits for your brain too.
Researchers working on our groundbreaking Insight 46 study shared their work looking at how blood pressure in midlife relates to brain health at the age of 70. They showed that higher blood pressure in midlife is linked with areas of damage in the brain and a smaller brain size at 70 years old. The team also found that a greater decline in blood pressure after 53 years old was linked to a smaller hippocampus – part of the brain affected in the early stages of Alzheimer’s disease. As they are looking at healthy older people, we don’t yet know what effect these blood pressure changes have on dementia risk, but future work by the group hopes to help answer this important question.
Being overweight or obese is a known risk factor for dementia, but how changes in our weight in midlife impact our brain health is less clear. Carol Franz from the University of California found that people who went from being in the normal BMI range at age 20 to being obese by age 62 had greater thinning of key areas of the brain. While they didn’t look at which people went on to develop dementia, other studies have linked brain thinning to an increased dementia risk. She suggested that maintaining a normal BMI throughout adulthood could help increase the brain’s resistance to disease processes associated with Alzheimer’s and other dementias.
Over recent decades, people’s lives have become increasingly sedentary, and one of the most sedentary activities out there is watching TV. To explore how sedentary behaviours affect brain health in midlife, Tina Hoang and colleagues used data recorded over a 25-year period, comparing how many hours of TV people watched a day with results from MRI brain scans taken at the end of the long study. They saw that long-term high levels of TV watching during adulthood were linked with a reduction in the size of key brain areas in midlife, suggesting that our increasingly sedentary lives could be impacting our brain health.
Fish oils and fatty acids
Claudia Satizabal discussed a new study looking at how levels of omega-3 fatty acids, commonly found in fish oils, were associated with brain health. Looking at a group of middle-aged people without dementia, she found that high levels of fatty acids in the blood were linked to better brain health. Although this study didn’t look at who went to go on to develop dementia, or the specific diet that volunteers were eating, previous research has linked a Mediterranean diet, which is high in fatty acids, to healthy brain ageing. With your help, we’re supporting a clinical trial at the University of Oxford looking at the impact of omega-3 and aspirin on dementia risk in those at high risk of the condition.
Although it can be hard to resist, we are regularly advised to limit the amount of sugar in our diets for important health reasons. One common way people consume sugar is through drinks like soft drinks, fruit juices and adding sugar to tea and coffee. Researchers based in New York set out to explore how these drinks could affect the risk of developing dementia. They found that the more sugary drinks someone has, the higher the risk of Alzheimer’s disease. In contrast to previous studies, they did not find that artificially sweetened or ‘diet’ drinks were linked to Alzheimer’s risk.
French researchers shared their work looking at how a person’s neighbourhood could influence their risk of dementia. Looking at groups of people living in France, the scientists were able to calculate how advantaged or deprived different neighbourhoods were and see how often people living in these areas went on to develop dementia. The researchers found that more people living in deprived neighbourhoods went on to develop dementia than those in advantaged areas. There could be many complex reasons behind this link, but the researchers suggested that differences in social activities available to people in each neighbourhood could be a player in influencing this higher risk.
Research suggests that a person’s ethnic background could also influence their dementia risk, and one factor that has not been explored before is how discrimination could play into this. Laura Zahodne spoke about the links between discrimination and brain changes associated with Alzheimer’s disease. She found that higher levels of perceived discrimination were linked to worse performance on memory and thinking tests, with African Americans and other non-hispanic ethnic minorities reporting the highest levels of discrimination. Her team explored the possible biological reasons for this link, finding markers of biological stress that could partially explained the link between discrimination and memory and thinking.
These are just some of the lifestyle and environmental risk factors that researchers have been discussing at AAIC 2018. Many of them are strengthening existing evidence, that what is good for your heart is good for the brain and that a physically and socially active lifestyle can also support a healthy brain as we age.
While there is no sure-fire way to prevent dementia, studies like these are shedding more light on the factors that affect the risk of diseases like Alzheimer’s, helping us to develop informed approaches to support better brain health at a population level. As more studies now look at the links between lifestyle in midlife and later life dementia risk, it’s becoming clearer that it is never too early to start looking after your brain.
With your kind support, Alzheimer’s Research UK last year injected an additional £2.4m into four brand new projects studying dementia risk, you can find out more about them here.
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