March 12, 2015
Here’s another reason to be good to your heart: It may ward off Alzheimer’s disease. A new study from Vanderbilt University Medical Center found that the heart’s ability to pump blood is closely correlated with the risk of developing Alzheimer’s and other forms of dementia.
For the study, published in the journal Circulation, researchers found that people with diminished heart function were two to three times more likely to develop serious memory problems, including Alzheimer’s disease, over the next 10 years.
“Heart function could prove to be a major risk factor for dementia and Alzheimer’s disease,” said study leader Angela Jefferson, director of the Vanderbilt Memory & Alzheimer’s Center. “A very encouraging aspect of our findings is that heart health is a modifiable risk. You may not be able to change your genetics or family history, but you can engage in a heart healthy lifestyle through diet and exercise at any point in your lifetime.”
Other studies have shown that what’s good for the heart is good for the brain. This study looked specifically at the heart’s ability to pump blood, using a measure called the cardiac index that reflects the amount of blood that leaves the heart and is pumped through the body. A low cardiac index value means there is less blood leaving the heart overall.
Dr. Jefferson and her colleagues analyzed data from children of those in the Framingham Heart Study, a landmark study of heart health that began in 1948. The current study followed 1,039 participants for up to 11 years, all of whom were free of dementia or serious memory problems at the start of the study.
During the study, 32 participants developed dementia, including 26 with Alzheimer’s disease. Those with worse heart function — even if they did not have heart disease — were much more likely to develop dementia than those with a normal cardiac index.
Remarkably, almost a third of the study participants had a low cardiac index, putting them at risk of Alzheimer’s and dementia with age.
“For the average adult, the brain accounts for 2 percent of overall body weight but receives as much as 15 percent of blood leaving the heart,” Dr. Jefferson said. “If there are changes in the heart’s ability to pump blood, the brain is resilient and does a great job at regulating blood flow to maintain a consistent level to support brain tissue and activity. But as we age, our vessels tend to be less healthy. They become less adaptable to blood flow changes, and those changes may affect brain health and function.”
Damage to the brain may take decades to develop, Dr. Jefferson said. She notes as well that this research points only to a risk factor.
“At present, there is no proven method for preventing dementia or Alzheimer’s disease,” she said. “But leading a heart healthy lifestyle could help. When 30 percent of the population is exposed to a potential risk factor like low cardiac index, that suggests it may be of significant public health concern.”
Lifestyle factors that may be good for the heart are also likely good for the brain, the results suggest. Many experts recommend a heart-healthy Mediterranean-style diet, key components of which include:
- An abundance of fiber-rich fruits, vegetables, cereals, nuts and beans;
- Choosing “good” fats like olive or canola oil, rather than butter or lard, and limiting dairy products like high-fat cheese and whole milk;
- Eating moderate amounts of fish and poultry, rather than red meat; and
- Drinking a glass or two of red wine a day.
Getting regular exercise and keeping weight down may also help keep the brain young. While many factors besides diet and exercise, including the genes you inherit and advancing age, play an important role in who ultimately develops Alzheimer’s, a heart-healthy lifestyle may help keep the brain young.
Source: Angela L. Jefferson, Alexa S. Beiser, Jayandra J. Himali, et al: “Low Cardiac Index Is Associated With Incident Dementia and Alzheimer’s Disease: The Framingham Heart Study.” Circulation, March 10, 2015