The age you gain weight plays a role in Alzheimer's risk

If you have put on weight during the pandemic and are worried about an increased risk of developing Alzheimer’s disease, you may not need to worry.

Earlier this year, YourLifeChoices reported on a study that found being overweight put more pressure on brain health and resulted in a greater risk of developing Alzheimer’s, but new research has suggested that it is much more complicated than that.

The latest research suggests that the age at which you put on weight plays an important role in your Alzheimer’s risk and that those who gain weight later in life have less to worry about than those who increase their body mass index (BMI) in midlife.

Read more: How to keep your brain fighting fit

The study, which zeroed in on BMI and genetic variants as risk factors for Alzheimer’s disease, found that a higher BMI later in life didn’t necessarily translate into a greater chance of developing the disease.

But before you get too excited and start tucking into a packet of Tim Tams, the findings do not suggest that people should consider gaining weight in their later years as a preventative effort.

Instead, researchers speculate that the analysis, which showed having a higher genetic risk combined with a lower BMI leading to a higher chance for progression to Alzheimer’s, was likely a consequence of progressive damage to the brain that is a hallmark of the disease.

Read more: Obesity weighs on Alzheimer’s

Professor Jasmeet Hayes from Ohio State University explained that brain regions affected by Alzheimer’s were also involved in controlling eating behaviours and weight regulation. 

“We don’t want people to think they can eat everything they want because of this lower BMI association,” she said.

“We know that maintaining a healthy weight and having a healthy diet are extremely important to keeping inflammation and oxidative stress down – that’s a risk factor that is modifiable, and it’s something you can do to help improve your life and prevent neurodegenerative processes as much as possible.

Read more: Study links dementia to poor kidney function

“If you start to notice rapid weight loss in an older individual, that could actually be a reflection of a potential neurodegenerative disease process.”

Previous research has found a link between obesity and negative cognitive outcomes, but in older adults closer to the age at which Alzheimer’s disease is diagnosed, the results have been mixed, Prof. Hayes said. 

She has focused her research program on looking at multiple risk factors at the same time to see how they might interact to influence risk – and to identify health behaviours that may help reduce the risk. 

“We’re trying to add more and more factors,” she said. “That is my goal, to one day build a more precise and better model of the different combinations of risk factors.

“Genetic risk is important, but it really explains only a small part of Alzheimer’s disease, so we’re really interested in looking at other factors that we can control.”

Statistical analysis showed that individuals with mild cognitive impairment who had both a lower BMI and higher genetic risk for Alzheimer’s were more likely to progress to Alzheimer’s disease within 24 months compared to people with a similar mild cognitive impairment diagnosis and a higher BMI, explained Jena Moody, another of the study authors.

“We think there’s interaction between the genetics and lower BMI, and having both of these risk factors causes more degeneration in certain brain regions to increase the likelihood of developing Alzheimer’s disease,” she said.

The relationship between low BMI and high genetic risk and progression to Alzheimer’s was stronger in males than in females.

Because brain changes can begin long before cognitive symptoms surface, a better understanding of the multiple risk factors for Alzheimer’s could open the door to better prevention options, Ms Moody said. 

“If you can identify people at higher risk before symptoms manifest, you could implement interventions and prevention techniques to either slow or prevent that progression from happening altogether,” she said. 

To date, scientists have suggested preventive steps include maintaining a healthy weight and diet and participating in activities that reduce inflammation and promote neuro-functioning, such as exercise and mentally stimulating activities. 

“We’re finding again and again how important inflammation is in the process,” Prof. Hayes said. “Especially in midlife, trying to keep that inflammation down is such an important aspect of maintaining a healthy lifestyle and preventing accelerated ageing.”

How have you managed your weight during the pandemic? Are you concerned about your weight or your Alzheimer’s risk? Share your thoughts in the comments section below.

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Written by Ben