They're both very different medical conditions and we tend to think of them in very different ways. Heart disease is often talked about as preventable through diet and lifestyle habits. But dementia is often thought of as left up to chance; a stroke of bad luck or family history leaving the cards stacked against you.
But doctors and scientists are increasingly speaking up that dementia is largely just as preventable as heart disease—and may be preventable in the same exact ways. Neurologist and renowned brain health expert Vladimir Hachinski, MD, was the lead author on a paper published by the World Stroke Organization stating that stroke doubles the chance of developing dementia and more than a third of dementias could be prevented by preventing stroke.
Behavioral neurologist, neuroscientist, and author of The 30-Day Alzheimer's Solution ($27) Dean Sherzai, MD, PhD, agrees whole-heartedly (no pun intended) that the connection between heart health and brain health deserves more attention. "In the past, heart health and brain health have been thought of as separate, but they are profoundly connected and integrated," he says. The connection offers encouraging news: Not only is heart disease preventable, but it means dementia could be largely preventable, too.
The heart-brain connection
The reason why both doctors say stroke prevention is key for dementia prevention comes down to two words: blood flow. "The brain only lives on glucose and oxygen; it needs a fresh supply of both," Dr. Hachinski says. "The brain is a very vascular organ with a lot of blood vessels." He explains that high blood pressure damages blood vessels, which can cause strokes, heart attacks, heart disease, and cognitive decline, including dementia. In the heart, high blood pressure can narrow and damage the vessels supplying blood to your heart—increasing the risk of heart attack and coronary artery disease. In the brain, damaged blood vessels can leak, depriving your brain of the nutrients it needs to function—leading to stroke. (High blood pressure can also cause blood clots, which is another cause of stroke.)
Dr. Sherzai adds that blood vessel damage happens over time. "Small vascular lesions accumulate over time, and that is what contributes to the risk of dementia," he says. "We now know that these vascular changes happen 10 to 15 years before any clinical signs of dementia or Alzheimer's start to [outwardly] show."
Unfortunately, it can be really difficult to see the effects of damaged blood vessels on the brain. "It's actually quite common for people to have little strokes in the brain without them even realizing it," Dr. Hachinski says. "[An estimated] 3 percent of people in their 40s have already had a stroke, which affects their ability to think. By the time people reach their 70s, 18 percent of people have had these little strokes." While Dr. Sherzai says the vascular lesions in the brain can be picked up through an MRI or CT scan, people often only undergo these (expensive) tests after some major health problem has already occurred. Monitoring other signs such as cholesterol or high blood pressure is an alternative way to detect blood vessel damage in the body that is easier.
Both doctors say that excessive sugar intake also damages both the heart and the brain, which means that protecting against diabetes could also protect against dementia. "One study of 33,000 people that excluded people with diabetes and only included people who were prediabetic showed that people who had insulin resistance also had a lower cognitive state," Dr. Sherzai says. "Insulin resistance, sugar, and glucose regulation directly affect neurons in the brain."
Actionable ways to protect your heart and brain
So how do you reduce your stroke and dementia risk? One way, both doctors say, is to eat foods high in antioxidants, which are good for blood flow. Berries, leafy greens, beans, coffee, and black tea are all high in antioxidants. Other foods that are good for heart health (and therefore, brain health) include fish, nuts, and whole grains.
Here's what else they say helps with blood flow: exercise. "As long as you're moving, you're getting the benefit," Dr. Hachinski says. "Whatever you think you can do, start. If that's 4,000 steps a day, great." Cardio exercise in particular has been shown to benefit the brain because as heart rate goes up, more oxygen is being delivered to the brain.
What about the age-old advice of doing crosswords to ward off dementia? Both doctors do emphasize the importance of continuing to learn new skills and test your memory. "Complex cognitive activities like learning a new language, musical instrument, dancing, or a book club involve multiple domains of the brain, which helps protect against dementia," Dr. Sherzai says. "It takes all of this—a healthy diet, exercise, and continuing to learn new skills—to protect the brain."
Both doctors reiterate the powerful link between heart and brain health and say it should be encouraging news to people who previously believed developing dementia was solely left to chance or family history. "You can profoundly reduce your risk of dementia by protecting your heart," Dr. Sherzai says. "And you can do that with the actions you take every single day."
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