A Healthy Heart Keeps the Brain Sharp
New research shows a wholesome lifestyle can prevent cognitive decline
Revealing just how connected the heart and mind are, a new study finds poor health at age 50 — on measures like physical activity, diet, and blood pressure — is linked to more than double the risk of dementia decades later. The result builds on other research showing that healthy living as early as age 18 affects brainpower later in life.
Dementia is a general term referring to impaired thinking, memory, and decision-making. Alzheimer’s disease is the most common type. There is no known cure.
“It is now widely accepted that dementia involves changes in the brain over the course of 15 to 20 years,” explains Archana Singh-Manoux of the University of Paris-Saclay in France, who conducted the new research with colleague Séverine Sabia. “Therefore, it is important to assess risk factors before the beginning of the disease process.”
The study, published August 7 in the journal BMJ, examined existing data on 7,899 British women and men who were 35 to 55 at the start of the 25-year study. Each person was given a cardiovascular health rating at the outset — poor, intermediate, or optimal — based on seven measures linked to heart health: smoking, diet, physical activity, body mass index, blood sugar, blood cholesterol, and blood pressure. Dementia cases were determined based on subsequent medical records and death registers. In all, 347 cases of dementia were recorded. The rate of dementia was more than double among those with poor initial heart health scores compared to those with optimal scores.
The implications from this study and many others are that the healthier the vascular system is in midlife, the lower the risk of subsequent dementia.
“The thrust of much of the research in dementia is on curative solutions,” Singh-Manoux says in an email. “The failure of all drug trials so far makes it important to consider prevention. For prevention to be effective we need to accept the long course of dementia.”
“The implications from this study and many others are that the healthier the vascular system is in midlife, the lower the risk of subsequent dementia,” Carol Brayne of the University of Cambridge and Fiona Matthews of the University of Newcastle write in an accompanying BMJ editorial.
Other research suggests the earlier that one adopts a healthy lifestyle, the better it is for the brain.
Scientists looked at data on 3,381 U.S. residents who were between 18 to 30 at the start of a long-term research project. 25 years later, the subjects took tests measuring memory, thinking speed, and mental flexibility. Those who started with higher than recommended levels of blood pressure, blood sugar, and cholesterol scored significantly lower on the cognitive tests in their forties and fifties, the researchers reported in Circulation in 2014.
“It’s amazing that as a young adult, mildly elevated cardiovascular risks seem to matter for your brain health later in life,” said study team member Kristine Yaffe, a neuropsychiatrist and professor at the University of California-San Francisco. “We’re not talking about old age issues, but lifelong issues.”
Several other studies have linked specific health issues to dementia.
A 2017 study in JAMA Neurology, involving 15,744 people in the United States over 25 years, found high blood pressure (defined as 140/90 or higher the time) linked to a 39% higher risk of dementia later on, while even slightly elevated blood pressure (120/80 or higher) was linked to a 31% higher risk of dementia.
In another study, researchers reviewed data on more than 1 million people across 38 years to find a 16% to 33% difference in dementia risk among those who were overweight versus normal weight, and an additional similar percentage increase among the obese.
Early-onset dementia, before the age of 65, is linked to chronic heavy drinking (4 or more daily drinks for men, three for women) in 57% of cases, researchers revealed last year in Lancet Public Health. “Alcohol-induced brain damage and dementia are preventable,” says study team member Jürgen Rehm.
Some 50 million people around the world have dementia, according to the World Health Organization, and each year 10 million more are afflicted. By 2050, the percentage of the elderly is projected to double, and dementia is expected to be one of several factors that strain society and its care systems.
“While age is the strongest known risk factor for cognitive decline, dementia is not a natural or inevitable consequence of aging,” WHO states in an overview of the problem.
What can you do? Studies suggest a plant-based diet rich in fruits and vegetables is best for the body and mind. Experts recommend avoiding white flour, white rice, added sugar, and highly processed foods. WHO advises limiting alcohol consumption and not smoking.
Physical activity, even just walking, has been shown to be good for the brain. In one study earlier this year, people who were not exercising were split into two groups: One did moderate aerobic exercise four times a week; the other did just stretching. After six months, they all took a test, and those who’d exercised tested as if they were several years younger cognitively. Also, the outer layers of the brains of the exercise group thickened, a sign of improved brain function.
As with other research, the new study does not prove that poor heart health causes dementia, but it shows that avoiding the known risks early in life helps stave off dementia later in life.
