Can you save your memory and stay sharp as you get older?

As we age, most of us will find our short-term memory and ability to process new information "not what it used to be." This is the cognitive equivalent of creaky knees — an inconvenient reminder that we're getting older.

Dementia, though, is something different. With dementia, multiple areas of thinking are compromised and the deficits are likely to get worse. By definition, dementia means memory and other cognitive areas deteriorate to the point that everyday tasks and decisions become difficult, and sometimes impossible. The causes of dementia are many, but in this country, Alzheimer's disease is responsible for between 60% and 80% of dementia cases.

Are there ways to avoid Alzheimer's disease? Not according to the 2010 National Institutes of Health conference on preventing Alzheimer's disease and cognitive decline. The group's consensus statement said there is no evidence of "even moderate scientific quality" that nutritional supplements, herbal preparations, diet, or social and economic factors can reduce the chances of getting Alzheimer's. Interventions intended to delay the onset of Alzheimer's didn't fare much better.

But it's not all bad news: Physical activity and cognitive engagement may help keep cognitive decline at bay

In terms of staying sharp (versus developing dementia) as we get older, the outlook was a little better, according to the group. Diet and nutritional supplements still didn't pass muster, and no medication was billed as preventing cognitive decline, but physical activity and cognitive "engagement" seem to hold some promise.

Why the difference? For one thing, by the time people are diagnosed with Alzheimer's disease (even mild or moderate cases), there may already be too much brain damage for exercise and other interventions to do much good.

In some studies depression has been associated with mild cognitive impairment and cognitive decline. Successful treatment of depression may not alter Alzheimer's, but the aspects of a person's thinking clouded by depression may improve with treatment.

To stay at the top of your game, stay on top of your health

A healthy mind relies on a healthy body. Elevated blood pressure and cholesterol, diabetes, excess weight, smoking, and a sedentary lifestyle all contribute to cognitive declines. Working to stay healthy helps you stay sharp.

Stop smoking. In 2010, a National Institutes of Health panel noted that current smokers were 41% more likely to exhibit cognitive declines than former smokers or nonsmokers.

Challenge your mind. Engaging in challenging board games, reading, working crossword puzzles, playing a musical instrument, and acquiring new skills may help keep your mind fit. These activities seem to expand the web of neuronal connections in the brain and help keep neurons nimble and alive.

Challenge your body. Brain cells crave a steady diet of oxygen. Physically active people lower their risk for developing dementia and are more likely to stay mentally active.

Get your rest. Too little sleep can affect memory. Six hours may be the minimum needed, although researchers testing college students found those who had eight hours were better able to learn new skills.

Watch your weight. Staying within a normal weight range lowers your risk for illnesses such as diabetes, hypertension, metabolic syndrome, and stroke, which can compromise the brain to varying degrees.

Check with your doctor. Are there any factors — such as medication side effects, vitamin deficiencies, depression, or chronic conditions — that could be better managed to help you stay as mentally sharp as possible? Discuss these issues with your doctor.