Having more arm and belly fat is linked to an increased risk of dementia, Parkinson's, a new study finds. Is there anything you can do about it?

Regular exercise and a balanced diet are well known to benefit your mental health on a day-to-day basis, but building strength while reducing excess fat may also protect your brain, reducing risks of dementia and Parkinson’s disease, new research suggests. The study, published in the journal Neurology, is the latest research to link belly fat to neurodegenerative diseases. But it goes a step further, breaking down the relationship between memory and motor function and various body compositions for men and women.

Here’s what to know about the new research, and the steps you can start taking today to protect your brain health as you age.

What did the new study find?

Over the course of the nine-year study, 8,224 out of more than 412,000 people developed some form of dementia or Parkinson’s disease (another neurological condition that can cause memory loss, as well as motor function issues). Among them, both men and women with more belly fat were 13% more likely to develop one of these neurodegenerative diseases, compared to those with low levels of fat around their middles. While the increase in risk was similar across the sexes, men of all body compositions were at greater risk for dementia and Parkinson’s disease than women.

But it’s not just the belly that matters to memory loss, according to the study. In fact, arm fat appeared to be slightly more predictive of dementia development. Those with high levels of arm fat had an 18% greater risk of being diagnosed with Parkinson’s, Alzheimer’s or another form of dementia.

The findings aren’t all bad news, though. People with “high muscle strength” faced a 26% lower risk of these neurodegenerative diseases.

What does body fat have to do with brain health?

“In [simple] terms, fat accumulation in the abdomen and arms appears to have a ‘poisonous’ and ‘inflammatory’ effect on other organs, including the cardiovascular system and neurological health, leading to a higher risk of degenerative diseases,” study author Huan Song, a professor of epidemiology at Sichuan University in China, tells Yahoo Life.

Scientists, including Song, believe that high levels of fat, especially around someone’s middle, influence dementia risks indirectly. “Central obesity, characterized by excessive abdominal fat, is associated with metabolic syndrome, inflammation and insulin resistance, all of which contribute to the risk of cardiovascular diseases and, consequently, neurodegenerative diseases,” Dr. Thomas Holland of the RUSH Institute for Healthy Aging tells Yahoo Life.

It’s not yet entirely clear exactly how heart disease and conditions like Alzheimer’s are related. It may be that the same risk factors — including obesity, lack of exercise, high cholesterol and smoking — raise risks for both, or that one can lead to the other. But, according to a review published in the Journal of the American Heart Association, the prevailing theory is that the link has something to do with high blood pressure and the hardening of the arteries, which trigger cell-damaging inflammation and a reduced supply of oxygen to the body and brain. In turn, these problems are thought to contribute to the development of problems such as plaques in the brain, while simultaneously limiting our biological ability to clear out these toxic deposits.

And while any form of obesity puts a person at greater risk for cardiovascular disease, belly fat is more predictive of deeper, systemic inflammation. “The location of fat, particularly around the abdomen, indicates a higher likelihood of … metabolic complications” that damage the cardiovascular system and, consequently, the brain, Holland says. Arm fat’s link to heart and brain diseases is less established, but Song and her team suspect it, coupled with low levels of strength, may be useful predictors of dementia risks too.

How is strength linked to memory loss?

Grip strength, which was among the factors examined in the new study, has long been considered a predictor of dementia and other chronic health conditions, including cardiovascular disease and death. Researchers think that grip strength — how much force you can generate, and keep generating, when squeezing an object — is affected by many of the same risk factors that contribute to dementia, including inflammation, making it a good stand-in for memory loss odds. “On the other hand, higher muscle strength is associated with better overall health, including cardiovascular health,” Holland says. “Muscle strength helps maintain metabolic efficiency, reduce inflammation and support healthy blood circulation, which are protective factors against neurodegenerative diseases.”

How to reduce fat and build strength to combat dementia and Parkinson’s

The study’s findings suggest that simple modifications to reduce belly and arm fat while improving strength can go a long way toward reducing your risks of both dementia and Parkinson’s. “To reduce the risk of neurodegenerative diseases, it is crucial to focus on a balanced diet,” says Holland. “Limiting the intake of foods high in trans and saturated fats — such as dark red meat, baked goods, fried foods, fast food, butter and high-fat dairy products — can significantly improve your health,” including by helping to reduce the amount of fat that accumulates around your belly.

But it’s not just about eliminating highly processed and fatty foods from your diet, Holland adds. It’s equally important to work on adding heart- and brain-healthy ingredients to your meals. These include nuts, extra virgin olive oil and fish such as salmon, all of which are rich in omega-3 and omega-6 fatty acids that help maintain brain health. Antioxidant-rich leafy greens and berries also support overall cognitive and cardiovascular health.

And incorporating regular exercise into your routine can both help improve strength and burn fat, helping to lower dementia risks. Holland recommends aiming to get 150 minutes of moderate to vigorous physical activity a week, which you can get by doing a 30-minute session of exercise for five days. “This routine should include weight training exercises two to three times a week to build muscle strength, along with stretching and balance exercises to enhance flexibility and stability,” Holland says. “These activities collectively contribute to better cardiovascular health and a lower risk of developing neurodegenerative diseases.”