7 Things to Do for a Healthier Brain After 50

3. Eat a heart-healthy diet

This is a diet that keeps cholesterol in check and promotes normal insulin activity — both of which can help reduce your dementia risk. But which diet is the most effective?

A new scientific statement from the American Heart Association ranks the DASH (Dietary Approaches to Stop Hypertension) diet at the top of the list. Designed to help people manage their blood pressure, DASH emphasizes vegetables, fruits, whole grains, legumes, low-fat dairy, and nuts and seeds. It limits red meat, sodium and sweets. Also ranking high on the new AHA list is the well-known Mediterranean diet, which emphasizes vegetables, fruit, whole grains, legumes, fatty fish, extra-virgin olive oil, and nuts and seeds.

“We have nice data that people who adhere to more of a Mediterranean-style diet are less likely to develop dementia,” Sabbagh says. In a 2021 study, a team of German researchers found that the Mediterranean diet was associated with larger brain volume and less beta-amyloid — the protein that forms the neuron-killing clumps that are a hallmark of Alzheimer’s disease.

The MIND (Mediterranean-DASH Intervention for Neurodegenerative Delay) diet is another approach, combining a Mediterranean-style plan with the DASH diet. It’s rich in neuroprotective foods (nuts, berries, green leafy vegetables, fish and olive oil). A landmark study showed that people around the age of 80 who followed it for five years had a surprisingly large cognitive advantage over those who didn’t. And a more recent study, published in March 2023 in the journal Neurology, found that people who followed the MIND or Mediterranean diets had fewer signs of Alzheimer’s disease in their brains.

4. Manage your weight

Obesity is a well-established risk factor for dementia. In a 2020 study, subjects with obesity were 34 percent more likely to develop dementia than those who were normal weight; the risk for women was even higher (39 percent). But how are the two linked?

Neurons, like all cells, use glucose for their energy source. But they can’t take it up without normal insulin function. Excess body weight (especially around the belly), not exercising, smoking and short sleep make it harder for insulin to move into cells, leading to insulin resistance. That’s a stepping stone to type 2 diabetes, and those with that condition have about a 60 percent increased risk of developing dementia, research suggests.

Losing weight is the best way to prevent, or even reverse, insulin resistance. According to the American Diabetes Association, losing as little as 5 to 7 percent of your body weight can be enough. If you’re taking an insulin-regulating medication like metformin, staying on track with it is extremely important for long-term cognitive health. A 2020 study found that people with type 2 diabetes who didn’t take metformin were more than five times more likely to develop dementia over six years.

5. Learn new things

Just like bodies, brains are meant to be active, Daffner says. Even animals benefit from brain stimulation. “We have beautiful animal work showing that mice who live in enriched, interesting environments have more neurons in the brain, more connections between neurons and a greater ability to resist or compensate for neuronal damage.”

One of the most important human studies on this subject was ACTIVE, which randomly assigned participants to three kinds of cognitive training (memory, speed and reasoning). Ten years later, when participants were around 82 years old, those who had taken the training still retained their gains. Compared with controls, they were doing better in their daily activities, including maintaining independence and driving, and had better thinking skills. Those assigned to the processing-speed training were 29 percent less likely to have dementia.

Crossword puzzles and sudoku, often suggested as brain exercises, may not offer the best training, Daffner points out, especially if they are too easy and don’t require “mental sweat.”

“The trick is to challenge yourself, but not with something so difficult that you give it up,” he says.

6. Get good sleep

We’re all familiar with the dopey fog of insomnia that resolves with an afternoon nap. But chronic short sleep — particularly in midlife — can damage the brain. Lack of sleep interferes with the brain’s nightly cleaning cycle. During deep sleep neurons produce less beta-amyloid and tau (proteins at the heart of Alzheimer’s) and secrete more of them as waste.

Sleep disorders are rampant in the U.S., affecting 50 to 70 million people, according to the American Sleep Association. Obstructive sleep apnea — a temporary cessation of breath, followed by gasping — is a common problem, and it has been associated with cognitive impairment and structural changes in the brain. The risk of developing sleep apnea is linked to obesity, increasing age and poor muscle tone — good reasons to lose weight and get some exercise.

If you’re having trouble sleeping, talk to your doctor. There are treatments, including therapy, that can help you get better rest.

7. Manage stress

“Stress is not just a state of mind but a state of body, and it exerts powerful physical changes in the brain.

Stress has direct adverse effects on health, including blood sugar, blood pressure and abdominal obesity,” Sabbagh says. “And it's a very serious disruptor of sleep.”

The stress hormone cortisol, which puts the body in fight-or-flight mode, also travels to the part of the brain known as the hippocampus. Animal studies have shown that cortisol can shrink the hippocampus. Other studies show that it actually changes the structure of neurons.

This work has now been extended to humans. One study of older adults found that those with more self-reported stress had significantly lower hippocampal size; another found that the risk of dementia rose by 2 percent for every stress symptom reported.

Mindfulness meditation can reverse some of those changes — and quickly. A study showed positive changes in a number of brain regions after just 40 days of the practice. Participants’ brain waves changed, too, and they reported improvements in depression. Interested in learning more? The American Psychological Association explains the benefits of mindfulness meditation and how to get started.

Editor’s note: This story, first published May 18, 2021, has been updated to reflect new research findings and new drug developments.