One of the hazards of living longer is the specter of Alzheimer’s disease. This thief of memory is relatively uncommon before age 60, but then increases with each passing half-decade, eventually afflicting just under half of those over age 85.
Numbers like these make it look as though losing your memory is part of normal aging. It isn’t. There is growing evidence that you might be able to prevent it, or at least push it back, with the same steps that help protect you from a heart attack or stroke.
Types of memory loss
The term dementia is an umbrella for damage to the brain that leads to memory loss, confusion, and changes in personality or speech. This damage can arise from a variety of causes, including head injury, malnutrition, and disease. Among older people, the most common causes are Alzheimer’s disease and vascular dementia.
Alzheimer’s is a progressive degeneration of the brain. Tangled strands of hairlike protein accumulate inside brain cells. Outside, clumps of a protein called beta-amyloid and debris from broken-down brain cells cluster around the connections between brain cells. The protein tangles and clumps kill brain cells and make it difficult for them to communicate with one another, leading to loss of memory, confusion, and other changes.
Degeneration is also a hallmark of vascular dementia. In this case it arises because lack of oxygen kills cells in one or more sections of the brain. This happens when small strokes disrupt blood flow or narrowed arteries seriously restrict it.
Some people have only Alzheimer’s disease, and some have only vascular dementia. But about half of those with memory loss and other symptoms have both.
Research suggests that similar scenarios – involving cholesterol-clogged arteries, inflammation, and risk factors for heart disease and stroke – contribute to both Alzheimer’s disease and vascular dementia.
Restricted blood flow in the brain may contribute to the cascade of events that leads to the tangles and clumps of Alzheimer’s. Deposits of beta-amyloid in blood vessels supplying the brain make them more fragile and likely to burst, which would cause a hemorrhagic stroke.
Some people develop the tangles and clumps associated with Alzheimer’s without showing signs of dementia. Autopsies show that memory loss and changes in thinking skills and personality are more likely to have occurred when tangles and clumps are accompanied by signs of strokes and restricted blood flow in the brain.
In other words, improving blood flow to the brain and working to prevent strokes may maintain memory well into old age.
Reverse the curse
A handful of studies link harmful habits or health issues in midlife with memory loss or declining thinking skills later on. In a 2005 report in the journal Neurology, researchers with a large California HMO found that 40-year-olds with four common cardiovascular risk factors – high cholesterol, high blood pressure, diabetes, and smoking – were more than twice as likely to develop dementia as those with none of these factors. In a more positive light, there’s growing evidence that healthful habits and changes are good for the brain and the mind.
Exercise. Walk, run, swim, cycle, garden, dance – better yet, do them all – to keep both brain and body in shape. Long-term regular physical activity has been linked with better cognitive function and less aging-related decline. A report from the Cardiovascular Health Cognition Study suggests that the variety of exercise, not just how much or how hard you exercise, may help ward off dementia. Exercise also looks like a way to prevent, and even treat, depression.
Blood pressure. Untreated high blood pressure speeds aging-related decay in thinking skills and memory. Pressure-lowering drugs may help, although it isn’t clear if one kind is better than another.
Dietary fat. Eating a lot of saturated and trans fat may promote dementia, while omega-3 fats may protect against the buildup of sticky beta-amyloid clumps in the brain. Omega-3 fats may also be a good way to prevent depression. Good sources of these healthful fats include salmon, mackerel, and other cold-water fish, as well as plant sources such as walnuts, canola oil, and flaxseed.
Cholesterol-lowering statins. A few studies suggest that people who take a statin (Lipitor, Zocor, generic lovastatin, etc.) are less likely to develop Alzheimer’s disease than those who don’t take this type of drug. If true, this would be an important “side effect” of statins, which are popular medications for fighting heart disease. At the same time, reports of statin-associated memory loss have appeared in medical journals.
The intersection of cardiovascular health and brain health is a relatively new field of research. So far there are tantalizing hints – but no guarantees – that doing what you can to keep your heart and blood vessels in good shape will do the same thing for your brain and your mind.
It’s a gamble worth taking.