Developing Alzheimer's or another form of dementia might seem inevitable, at least if you live long enough. The latest stats show that about 9% of Americans over the age of 65 suffer from dementia, but if you make it to your 85th birthday your chances jump to nearly 33%. Those numbers are certainly alarming, but there's actually a lot you can do to reduce your risk, says David Perlmutter, MD, a neurologist in Naples, Florida and author of several brain bestsellers, including Grain Brain and Brain Maker.

The key moves to make, says Perlmutter, are centered around living a healthy lifestyle. Although your genes very likely play an important role in whether or not you develop dementia—a constellation of symptoms that includes memory loss and difficulties speaking or writing coherently, recognizing familiar people and places, and performing everyday tasks—taking good care of yourself (or not) is also crucial.

Here are 8 common mistakes to avoid if you're hoping to cut your risk of this dreaded disease.

(Discover the 5 best foods for your brain and other cutting-edge natural tips in Prevention’s Ageless Brain)

Gaining weight

We know you're not intentionally piling on the pounds, but if the scale has been climbing, watch out: People with a high body mass index (BMI) are more likely to develop dementia than those with a normal weight, according to a new UK study published this past November in the medical journal Alzheimer’s & Dementia. Each five-unit increase in BMI (roughly 30 pounds for a person 5’7’’) raises your risk by about a third.

Burn fat with this 10-minute workout you can do at home: 

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Rising blood sugar

Uncontrolled type 2 diabetes has long been linked to dementia, as elevated sugar levels damage all your organs, including your brain. But even a slight rise in blood sugar can be problematic: People whose average blood sugar was 115 mg/dl—in the prediabetes range—were almost 20% more likely to develop dementia than those with normal blood sugar, according to a Harvard study published in the New England Journal of Medicine.

“We know that even slight elevations in blood sugar go lockstep with inflammation, which damages your brain,” says Perlmutter. To make sure you're not creeping into the prediabetes (or diabetes) range, make sure to get screened annually if you’re over age 45; start younger if you’re overweight or have other risk factors. (Here's an easy test that can tell you if you're at risk—and it involves cute animals.) 

Being a couch potato

Breaking a sweat doesn't just help you look more toned. Exercise raises levels of brain derived neurotrophic factor (BDNF), a protein that prevents the death of existing brain cells and helps build new ones, says Perlmutter. People with the highest levels of BDNF have the lowest levels of dementia, according to a Boston University study published in JAMA Neurology.

If you haven't been especially active, don't panic: It's never too late to start, and research has found that people over the age of 50 who reported memory problems but walked about 9,000 steps a week more (roughly four miles) than a control group showed improvements in both memory and cognitive ability. Perlmutter recommends logging about 30 minutes of moderate to vigorous exercise (like brisk walking or jogging) daily.

MORE: The Beginner's Guide To Walking For Fitness

Skimping on foods with fat

Eating fat doesn't necessarily make you fat; it might protect your body and your brain. “People who eat a higher-fat diet tend to eat less carbs, particularly processed carbs, which can cause inflammation that leads to dementia,” says Perlmutter. In fact, people who consumed high levels of fat—more than a third of their total calories—were 42% less likely to experience cognitive impairment than those whose diets contained less than a quarter of fat, according to a 2012 Mayo Clinic study.

Aim to keep your carb intake below 50% of your total calories, and focus on good-for-you, heart-healthy (and thus brain-boosting) fats such as those found in olive oil, flaxseed, nuts, and fatty fish like salmon. (Get started by cooking these 6 recipes with the perfect balance of healthy saturated fats.) 

Being D deficient

Many people don't get enough of this sunshine vitamin, and you actually need more of it as you age. (The RDA for vitamin D is 600 IU for people under the age of 70 and 800 for those over 70.) It's important for a variety of bodily functions, and brain health seems to be among them: People with the lowest levels of vitamin D had a 53% increased risk of developing dementia compared to participants with higher levels, according to a study published in the journal Neurology. And those who were severely deficient had a 125% increased risk. Ask your doctor if you should consider a supplement or take a blood test to check your levels.

MORE: 15 Surprising Ways To Get More Vitamin D

Sipping diet drinks

People who down at least one artificially-sweetened beverage a day are almost three times as likely to develop Alzheimer's disease over a decade than those who abstain, according to a Boston University study published this past April in the journal Stroke. That doesn't mean you should order the regular soda: Other research has found that a daily dose of either a sugary or diet drink is linked to smaller brain volume.

Sweet drinks (whether they contain sugar or artificial sweeteners) seem to trigger inflammation that harms the brain, says Perlmutter. They may also predispose people to diseases that increase dementia risk, such as heart disease and type 2 diabetes. Stick with unsweetened iced tea, plain seltzer (feel free to toss in some fresh fruit), and, of course, water. (These cute, functional water bottles will make it easy to reach your hydration goals.) 

Living in congestion

City dwellers, beware: People who live within 50 meters of high-traffic roads have a 7% higher likelihood of developing dementia compared to those who live more than 300 meters away from them, according to a Canadian study published last January in the Lancet. Previous research has found a link between air pollution and heart disease, so researchers suspect that the air pollution itself gets into the bloodstream and causes inflammation, which impacts your heart and your brain.

MORE: 10 Ways To Prevent Heart Disease

Staying single

Need a nudge to check out match.com? Lifelong singletons are 42% more likely to develop dementia compared to married folks, while widowers are about 20% more likely, according to a study published this past November in the Journal of Neurology Neurosurgery & Psychiatry. One reason, according to researchers, is that people who aren't paired off may feel more lonely and depressed, which are risk factors for dementia.

No matter your relationship status, make sure you have plenty of social support, say Perlmutter. Spend time with friends, volunteer, and generally stay involved in your community. Not only will you have a better chance of staying sharp, but you'll be happier, too.

Lettermark
Hallie Levine

Hallie Levine is a freelance writer who has written about health and fitness for more than 20 national publications, including Glamour, Newsweek, and the New York Post. She lives in in Fairfield, CT with her three kids and dog.