07/19/2013 11:22 EDT | Updated 09/18/2013 05:12 EDT

The Best Way to Prevent Dementia

Three independent studies from Europe confirmed what experts suspected all along but had not been able to say with certainty, namely that both physical health and mental activity are both contributing factors in the slowing, if not the prevention, of age-related cognitive decline.

One study from the United Kingdom found that dementia rates in seniors (age 65 years and older) from England and Wales dropped by an astounding 25 percent just over the last decade.

Another, this one from Denmark, discovered that nonagenarians (90 and older) scored substantially higher on mental fitness tests than their predecessors just a decade ago.

In the same week, French researchers published a study showing that workers in their 60s who postponed retirement, even for only a few years, were less likely to develop Alzheimer's disease and other forms of mental health problems than their earlier retiring counterparts.

The findings somewhat contradict repeated warnings of the past that age-related dementia was on the rise and would affect the now retiring baby boomer generation in unprecedented numbers. While these predictions still may come true for parts of this population, it seems now that better dietary and lifestyle choices can indeed help reduce the risk of cognitive decline later in life. As other studies have shown before, education also plays a key role.

Some experts have warned that the study results from Europe may not necessarily be applicable to other parts of the world, not even to the United States. One of the reasons for this could be that the health status of the participants may have been superior from the start due to easier access to medical care, higher education levels, and greater public awareness of important health matters in these countries.

The Danish study seems to confirm these assessments. It's primarily the populations of countries with higher standards of living that are surviving into their tenth decade in rapidly increasing numbers. The study findings suggest that these people not only live longer, but that they also continue to function better overall.

The French study, which involved almost half a million men and women who kept working beyond their official retirement age, found that staying in the workforce can produce significant benefits for mental health.

"For each additional year of work, the risk of getting dementia is reduced by 3.2 percent," said Dr. Carole Dufouil, an epidemiologist at the Institut National de la Santé et de la Recherche Médicale (INSERM) and author of the study report to CBS News.

Critics have cautioned against the conclusion that retiring per se can cause cognitive decline. While remaining active and engaged, both intellectually and socially, is undoubtedly of great importance for healthy aging, it must also be said that work-related stress can take a heavy toll, especially as people grow older. Meaningful retirement filled with positive experiences like tending to hobbies or traveling can be more healthful than hanging on to boring routines.

All these studies essentially point to the same thing: Although there is no guarantee that anyone of us can escape mental decline as we age, we are not completely helpless in trying to prevent it from happening. But preserving of our mental capacities, like our physical abilities, must not begin in the later stages of life but as early as possible. It's a lifetime's work.

Food and Health with Timi Gustafson, RD