We do not yet have medications that can halt or reverse dementia, but there are plenty of ways to help lower the chances of developing it—including some steps you may already be taking. That’s the main message from a new report from the Lancet Commission, a panel of experts gathered by The Lancet medical journal to review the latest evidence on dementia prevention. It estimated that nearly half of dementia cases worldwide could be avoided, or at least delayed, by tackling 14 risk factors.

Many of the risk factors probably sound familiar, because they’re notorious contributors to cardiovascular disease and other major ills (and most have previously been linked to dementia). But some others might surprise you. The full list includes smoking, being sedentary, excessive alcohol intake, obesity, high blood pressure, high cholesterol, diabetes, depression, brain injury, social isolation, hearing loss, untreated vision problems, lack of mental stimulation, and exposure to air pollution.

Published in August, the report is based on an analysis of dementia research conducted over the past several years, since the Commission’s last publication in 2020. That report pointed to 12 potentially changeable risk factors for dementia. This latest update adds two more—namely, poor vision and high cholesterol—and says the evidence is stronger than ever that addressing these risk factors can go a long way toward preventing dementia.

Here’s a summary of the specific actions the Commission recommends for supporting your brain health:

• Take care of your heart to take care of your brain. As the saying goes, what’s good for the heart is good for the brain. So if you have high blood pressure, high cholesterol, or diabetes, get them under good control—whether through lifestyle changes, medication, or both. Those conditions may take a toll on cognition (memory and thinking skills) by damaging the small blood vessels that feed the brain. They also raise the risk of suffering a stroke, which is a major cause of vascular dementia (the second most common type of dementia, after Alzheimer’s disease). Beyond that, research suggests diabetes may contribute to inflammation of the brain tissue, while an overload of cholesterol in the brain might help promote the abnormal protein deposits that are seen in Alzheimer’s.
• Maintain a healthy weight. A number of studies have linked obesity in middle age to an increased risk of dementia later in life. Part of that connection might be explained by high blood pressure and diabetes, which are more common among people with obesity. But it’s also possible there’s something about excess body fat itself (like diabetes, it may fuel inflammation in the brain, for example). The good news is, research suggests that losing even a few of those extra pounds, through diet changes and exercise, may help improve cognitive function.
• Speaking of exercise, it might help shield your brain regardless of your weight. Research suggests that regular physical activity at any age helps people stay mentally sharper—possibly by aiding blood flow to the brain and reducing inflammation, among other benefits. Strive for at least 30 minutes of moderate exercise, like brisk walking, on most days of the week.
• If you smoke, now is the time to quit. Smoking raises the risk of heart disease and stroke, and the toxins in tobacco smoke might harm brain cells directly. Again, there’s encouraging news here: Studies suggest that kicking the habit, especially before age 65, reduces smokers’ excess dementia risk.
• Keep your mind active. Higher education levels are tied to a lower risk of dementia, and the theory is that education offers people more “cognitive reserve”—the ability of the brain to keep functioning well, even after damage from the dementia process begins to set in. Research suggests that people can also boost their cognitive reserve by continuing to learn new things and challenge their minds as they age—by reading, playing games, doing crafts, and having an active social life, to name a few ways.
• Mind your mental and social well-being. Depression is linked to dementia in a complicated way: Studies suggest it can be a symptom of early dementia, a reaction to waning cognitive abilities, or a cause of those declines (particularly depression during middle age). One theory is that depression-linked stress hormones might injure the brain. Other possibilities are less direct: People who are clinically depressed may neglect their physical health or become socially isolated—which, itself, is on the list of risk factors for dementia. The “why” isn’t completely clear, but when people lack social connections, it can rob them of a source of mental stimulation and a buffer against stress. Fortunately, there’s some evidence that depression treatment can help mitigate the excess dementia risk linked to the disorder.
• Wear a helmet if you ride a bike or take part in other activities where head injury is a risk. Serious brain injuries may raise the odds of developing dementia, or hasten its onset; the evidence is mixed as to whether concussions (which are considered a mild brain injury) are linked to dementia risk later in life.
• If you drink, do so only in moderation. Heavy drinking is well known to harm the brain.
• Have vision and hearing problems treated. Both have now been tied to heightened risks of dementia, though the reasons aren’t clear. It’s possible that brain areas regulating hearing or vision are damaged at some point during the early dementia process. On the other hand, people with poor vision or hearing might become socially withdrawn and have fewer ways of staying mentally stimulated.
• The last risk factor is a hard one for people to address on their own: air pollution. Studies suggest that living in areas with poorer air quality raises the odds of dementia, possibly because fine particles in dirty air can be inhaled into the lungs and get absorbed into the bloodstream and the brain. The Lancet Commission advocates for policies to improve air quality globally.

BOTTOM LINE: Dementia is incredibly complex—and it also involves genetics and other factors that, unfortunately, you can’t change (like getting older). Each of the factors discussed above, on their own, probably have a fairly small effect on one’s likelihood of developing dementia. That’s why it’s so important to look at your health and lifestyle habits as a whole. Some studies are doing that, too—testing interventions that target multiple lifestyle factors at once, with the goal of slowing down cognitive decline in older adults, or even reversing it. One recent clinical trial, for example—by Dr. Dean Ornish—has yielded promising short-term results with a program that combines a plant-based diet, exercise, stress reduction, and social support (watch for our interview with Dr. Ornish that will be published in December). All this goes to show that dementia does not have to be an inevitable part of aging, and there are many ways we can support our lifelong brain health.