Healthy Diet Helps Prevent Alzheimer's

July 20, 2004 -- Remember frowning at your spinach and broccoli as a kid at the dinner table? Maybe you still do it today. But eating these veggies may benefit your mental functioning in the long run.

New findings show that eating green leafy vegetables and cruciferous vegetables such as broccoli, cauliflower, and brussels sprouts can preserve mental functioning in later years, possibly delaying the onset of Alzheimer's disease.

A study, presented at this week's Ninth International Conference on Alzheimer's Disease and Related Disorders, shows that women who ate green leafy and cruciferous vegetables during their middle ages maintained more of their mental capabilities as they entered their 70s than those who ate less of these vegetables.

Those who ate the highest amount functioned one to two years younger mentally in comparison to those who ate less.

The study's lead researcher, Jae Hee Kang, D.Sc., instructor in medicine at Harvard Medical School in Boston, says that by delaying the onset of Alzheimer's disease by just one year in the future could reduce the number of cases of the disease by 800,000. And by delaying the onset by two years further reduces the number of cases by 2 million.

Eating Your Fruits and Veggies

According to researchers, cognitive decline in memory, judgment, and awareness, such as forgetting where you put your keys or not being able to perform everyday tasks like making a meal, is considered a risk sign for Alzheimer's disease — a disease which affects around 4.5 million Americans.

Diets rich in fruits and vegetables have been known to play a role in decreasing the risk of heart disease, doctors say. Now they might play a role in decreasing the risk of Alzheimer's disease as well.

"There is ample data that fruits and vegetables are protective against various chronic conditions," says Kang. "And because of those things there is a very good chance that there is cause that it would be protective against Alzheimer's disease."

Leafy greens and cruciferous vegetables are both high in folate and antioxidants. Kang says these vitamins have been shown to protect against memory decline.

Leafy Greens, ‘Cruciferous’ Veggies Rule

During the Nurses Health Study, Kang and fellow researchers evaluated the diet and health status of more than 13,000 women over a 27-year period. The women were also given tests over the telephone to assess their attention, thinking, and memory skills.

Researchers found that increasing the overall amount of fruits and vegetables in one's diet did not affect the overall decline in mental functioning. Also, there was little relationship between eating fruits and cognitive decline, note the investigators.

They then looked at only vegetables.

"We looked at a lot of different fruits and vegetables. We looked at them together and separately. All vegetables were associated with a lower rate of decline," says Kang.

They found that cognitive decline was slower among those who ate the most vegetables, particularly of the green, leafy and cruciferous variety.

Those in the study who consumed high amounts of green leafy vegetables ate eight servings a week, while a high consumption of cruciferous vegetables was five servings a week.

Romaine lettuce and spinach protected more against cognitive decline because of their dark, nutrient dense makeup in comparison to other green, leafy vegetables such as iceberg lettuce.

Kang notes that even though dark leafy greens and cruciferous vegetables were the most beneficial, they were the least consumed foods in the study. Because of the findings, Kang advises that the public should be educated on eating more of these particular vegetables.

What’s Good for You

Dr. John Messmer, associate professor of family and community medicine at Penn State College of Medicine in Hershey, Pa., agrees that dark leafy greens and cruciferous vegetables are beneficial.

Messmer says that eating vegetables decreases the risk of atherosclerosis, or hardening of the arteries. Moreover, he states that preventing atherosclerosis, by controlling blood pressure and cholesterol, will also reduce the risk of Alzheimer's disease.

He suggests not smoking and getting regular exercise. He also suggests eating a diet rich in dark green vegetables, tomatoes, whole grains, and fish high in omega-3 fatty acids. Messmer says that beer, chocolate and red wine may be consumed as well, but not to exceed normal weight.

Despite the study's support for vegetables, Kang cautions that since this is one of the first studies to examine produce consumption and cognitive decline, more research still needs to be done to further confirm the results.

Dr. Leon Thal, professor of neurosciences at the University of California, San Diego also thinks that more research needs to be done. He warns that epidemiological studies, such as Kang's, often show an association that cannot be duplicated in controlled clinical trials. He feels that associations may be caused by other factors.

The number of people with Alzheimer's disease is expected to climb to 16 million by the year 2050, according to the Alzheimer's Association.