To keep your brain healthy as you get older, focus on your heart health now. That is the conclusion of a recent study by scientists at Karolinska Institutet in Stockholm, Sweden. Bottom Line Personal spoke with one of the study’s lead researchers, Chengxuan Qiu, PhD, about the ways in which heart health directly influences how our brain ages.
In 2010, the American Heart Association (AHA) created Life’s Simple 7—seven modifiable health metrics that can positively influence heart health and reduce risk for heart disease. Four of those metrics are behavioral—being physically active, eating a healthy diet, having a normal body mass index (BMI) and not smoking. Three are biological—normal or well-controlled total cholesterol, blood pressure and fasting blood sugar. (Editor’s note: The AHA added getting adequate sleep to this list after the study was underway.) You have control of all of these metrics…and taking control of them benefits your heart and supports your brain health!
The heart, the brain and the mind (or cognition) all are connected, especially during the aging process. Cognitive decline and heart disease share many risk factors, including smoking, high blood pressure and diabetes. What’s more, heart disease can contribute to cognitive decline by causing inadequate blood supply to the brain, and that sets the stage for forms of dementia. The Karolinska Institutet study looked specifically at how adhering to Life’s Simple 7 could influence the structural changes of brain aging among older people.
Most of us know about the link between amyloid and tau brain lesions and dementia…and about how plaque buildup in large arteries increases stroke risk. But perhaps you are not aware that damage to micro vessels, the smaller blood vessels in the brain, can deprive the brain of vital oxygen and nutrients. Called microvascular lesions (MVLs) or small vessel disease (SVD), this damage can cause three different types of impairment—physical, such as slowed walking speed and balance problems…cognitive, including problems with memory, language and executive function…and emotional, which can show up as symptoms of depression. The damage to these vessels shows up on brain MRI scans as a higher volume of white matter hyperintensity, or WMH…lacunes, or small deep lesions or cavities…and a new biomarker of damage, the appearance of perivascular spaces that appear outside the roots of very small vessels. Another common MRI marker of cerebral SVD are microbleeds, small areas of hemosiderin deposits (hemosiderin is derived from the disintegration of red blood vessels).
To assess the protective role of Life’s Simple 7 on brain health, the study followed 317 participants from the Swedish National Study on Aging and Care, a multidisciplinary study of aging and health among people 60 and older in the Kungsholmen district of Stockholm. Among the participants were people who were genetically more susceptible to metabolic risk factors, such as diabetes and high cholesterol, so researchers could determine whether having such genes increases risk for faster vascular brain aging.
The participants were followed for an average of 5.5 years. For each of the seven health metrics, they were given a score of 0, 1 or 2, depending on how well they adhered to them, with 14 being the highest total score possible. Examples: For the metric of smoking, current smokers were given a score of 0…previous smokers who had stopped at least five years earlier got a 1…and those who never smoked, 2. People with a BMI of 30 or higher were given 0…those who were overweight, 1…and those at a healthy weight, 2. Participants’ overall scores fell into three groups—unfavorable (with a mean score of 5.31)…intermediate (a mean of 7.5)…and favorable (a mean of 9.78). Participants had repeated MRI scans to measure the signs of MVLs.
Results: The findings showed the impact that cardiovascular health can have on maintaining vascular brain health in older adults. Overall, having an intermediate or favorable score was linked to slower progression of WMH volume versus having an unfavorable score. Intermediate to favorable scores on the biological metrics in particular (normal or well-controlled total cholesterol, blood pressure and fasting blood sugar) were related to slower progression of WMH among people ages 60 to 72 years, though not among people 78 years or older. (Why the brain of a person in his/her late 70s or older doesn’t respond in the same way is complicated. There may be existing damage that limits the brain’s abilities. Having low blood pressure or low LDL cholesterol has been linked to increased WMH volume in old age, and low total cholesterol late in life can accelerate the brain aging process.)
Having a higher genetic predisposition to the metabolic risk factors (diabetes and high cholesterol) was linked with faster accumulation of WMH among people with an unfavorable or intermediate score but not among those with a favorable score, and in particular, with favorable scores on the behavioral metrics (not smoking, being physically active, eating a healthy diet and having a normal BMI).
What that means: Healthy behaviors may counteract the detrimental effects of these genes and, in turn, slow the progression of vascular brain aging.
The way to keep your brain healthy is to prevent MVLs…and the way to do that is to adhere to Life’s Simple 7, now Life’s Essential 8—being physically active, eating a healthy diet, having a normal BMI, not smoking and getting good sleep as well as keeping total cholesterol, blood pressure and fasting blood sugar under control.
The sooner you take action, the better. If you don’t protect your heart health—say, your blood pressure isn’t controlled in midlife—heart disease and stroke risk will start at a much younger age, perhaps in your 40s or 50s, and then start to affect your brain by your 70s. If you have high blood pressure, cholesterol and/or blood sugar, controlling your numbers is essential, and that means working with your doctor on a plan and sticking to it.
Reminder: It is important for brain health to maintain or boost your cognitive reserve—that bank of cognitive abilities that you add to throughout your life with education and continued learning, mentally demanding activities at leisure time or work, and social engagement. The greater your reserve, the better your brain is able to function, even with microvascular damage.
