En español | The search for effective treatments, not to mention a cure, for Alzheimer's disease and other memory disorders has been a frustrating path of disappointment. Thirty-three investigational drugs have made it to the final stage of experimental testing, and every one has failed. In fact, doctors are still treating the symptoms of Alzheimer's with the same medications they've had since 2003.
But as treatment research struggles, data on prevention continue to soar. Multiple lines of evidence from all around the world show that it is possible to reduce the risk of dementia as we age — just not with drugs.
"We would all like to just take a pill to solve challenging medical problems,” says Kirk R. Daffner, M.D., chief of cognitive and behavioral neurology at Boston's Brigham and Women's Hospital and a professor of neurology at Harvard Medical School. “And a one-and-done approach is certainly attractive. But that is probably not going to happen with Alzheimer's disease.”
What does seem to work, however, is a healthy lifestyle. Here are seven habits that can boost your brain health in your 50s and beyond.
1. Keep your blood pressure under control
Recommendations that promote heart health also promote brain health. But the story is more complicated than just ensuring good blood flow to the brain.
Heart and brain health are woven together not only by lifestyle factors but by genetics, cholesterol metabolism, and the health and integrity of the cardiovascular system — from major vessels to the tiniest capillaries — says Marwan Sabbagh, M.D., director of translational research at the Cleveland Clinic's Lou Ruvo Center for Brain Health in Las Vegas.
Blood pressure management — which can be achieved with steps including a well-balanced diet, exercise and medication — is Sabbagh's top recommendation to ensure healthy cognitive aging. “It's one of the best ways to optimize brain health,” he says.
A 2019 study, “SPRINT MIND,” assessed dementia risk in patients who had either intensive (120 mmHg) or standard (140 mmHg) blood pressure control. Patients in the intensive control group were 19 percent less likely to develop mild cognitive impairment (considered to be pre-Alzheimer's) and 17 percent less likely to develop all-cause dementia. Their brains also had fewer lesions — indications of tiny damaged areas.
If you notice that your blood pressure is creeping up, talk with your health care provider about the best treatment plan.
2. Get regular exercise
Beyond increasing blood flow to the brain, exercise — particularly running — can be a boon for brain health because it generates the release of a protein called brain-derived neurotrophic factor (BDNF), which promotes the growth of the cells that send and receive signals from the brain, called neurons. BDNF also “increases the connections between neurons, and it sustains them in the face of environmental and other challenges,” Daffner explains.
One study even found that exercise increased the size of the hippocampus (the brain region destroyed by Alzheimer's disease) by 2 percent; that's the equivalent of “reversing” age-related volume loss by one to two years.
National guidelines recommend that older adults get two to five hours of exercise each week. But the best exercise program is the one you can consistently do, Daffner says. He likes Fitbit and step-tracking phone apps so you can see your progress in real time. Group exercise can also be helpful because it combines the benefits of working out with important social connections.
"Being physically active is one of the most important things that we have control over,” Daffner says. “And it's not just for brain health — it promotes better sleep, lower stress, improved cardiovascular health and even lessens the chance of falls as we get older."
3. Eat a heart-healthy diet
This is a diet that keeps cholesterol in check and promotes normal insulin activity — both of which reduce your dementia risk. But which diet is the most effective?
"We have nice data that people who adhere to more of a Mediterranean-style diet are less likely to develop dementia,” Sabbagh says. “And now there are a few interventional studies that show positive effects on cognition."
In early May a German team published the strongest-yet evidence on this. A Mediterranean diet, which is rich in vegetables, fish and heart-healthy fats, 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 diet is another approach, combining a Mediterranean-style plan with the American Heart Association's 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.
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.
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 randomized 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. There are dozens of brain-training programs for sale, and not all are created equal. The Alzheimer's Association has some brain fitness recommendations. Your health care provider may be able to suggest some, too.
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., according to the American Sleep Association, affecting 50 to 70 million Americans. Obstructive sleep apnea (OSA) — 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. It's also linked to obesity, increasing age and poor muscle tone — good reasons to lose weight and get some exercise. Sleep physicians can help with medication, OSA equipment and psychological training systems that are designed to 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 can explain the benefits of mindfulness meditation and how to get started.