More than 2 million Americans are 90 years of age or older, making them part of the fastest growing age segment of the American population. It is estimated that by 2050 this age group will increase to 10 million Americans.

This expected demographic change is already shifting job needs and will definitely challenge many aspects of health care.

For those who are in this "Young at Heart" age group and still active, the most concerning issue often is how to maintain a healthy and functional brain.

In today’s fast-paced lifestyle, we all have "senior moments." As these "senior moments" increase or balancing a checkbook becomes more of a challenge, thoughts of how to maintain a good memory occupy more of our thoughts.

Longevity research is being done throughout the nation, but a study that appears to be at the forefront is called "The 90+ Study." Dr. Claudia Kawas and Maria Corrada at the University of California, Irvine are the lead investigators and what they have uncovered will cause many researchers to rethink healthy aging and particularly brain health.

In 1981, more than 14,000 residents living in a large retirement community in Orange County, Calif., responded to a research questionnaire. All were over 50 years old — the requirement to live in that community.

In 2003, The 90+ Study began and started by following up to find each questionnaire respondent. The goals of the study focused on food, activity and lifestyle factors related to living longer. They also set out to better understand which factors affect memory function as well as physical changes in brain anatomy.

Question: What were the major findings of The 90+ Study related to diet?

Answer: Although some might expect that the active 90+ group was focused on eating healthfully, results were not consistent. What was found is that those who consumed moderate amounts of alcohol or coffee lived longer than those who did not drink these beverages. Additionally, those who were overweight (but not obese) in their 70s tended to live longer than those who were of normal weight or underweight.

Q: Did exercise play a role in healthy aging?

A: The 90+ Study results showed that exercise is a key component to staying both physically and mentally fit. The exact mechanism is not known but from animal studies, it appears that as we age nerve connections in the brain decrease.

Both physical and cognitive stimulation improve the connections and in turn improve cognitive functioning of the brain. The amount of physical exercise that benefited the 90+ oldsters was only about 20 minutes a day and could be a combination of walking and gardening or other activity.

Q: What about Alzheimer’s?

A: This aspect of the research is quite interesting. Now that there is technology to evaluate the brain for the tangles so often associated with cognitive loss, the previous anatomy issues no longer seem to be the major issue.

Some individuals with lots of brain anatomy issues did not have memory problems, whereas some without anatomy issues had much more of the problems associated with an aging brain. One finding indicated that many individuals with memory loss may have had multiple transient ischemic strokes often called mini-strokes.

Having a reasonable social network was important, as was keeping blood pressure from being too low. There is still a great deal to learn.

Alan Titchenal, Ph.D., C.N.S., and Joannie Dobbs, Ph.D., C.N.S., are nutritionists in the Department of Human Nutrition, Food and Animal Sciences, College of Tropical Agriculture and Human Resources, University of Hawaii-Manoa. Dobbs also works with University Health Services.