People aged 65 and older who eat lots of vegetables have a slower slowdown in age-related mental function, researchers report in Neurology.
The findings come from Martha Clare Morris, ScD, and colleagues at Chicago's Rush University Medical Center.
They studied more than 3,700 Chicago blacks and whites who were at least 65 years old in 1993-2002.
Participants took tests of mental skills including memory and attention when the study started, and again three and six years later.
They also completed surveys about the foods they ate, including a list of 28 vegetables and 14 fruits, and their vitamin use.
The researchers split participants into five groups based on average daily vegetable servings, which ranged from less than one daily serving to four daily servings.
Keeping the Mind Sharp
All participants had some mental slowdown as they aged.
But the yearly slowdown was 40% slower for people who ate the most vegetables -- three or four servings daily -- compared with those who ate less than one serving daily.
No such pattern was seen with fruit, which surprised the researchers.
"This was unanticipated and raises some questions," Morris says in a news release from the American Academy of Neurology.
She and her colleagues aren't sure why vegetables, but not fruits, were linked to a slower decline in mental function.
It will take more work to figure that out. Meanwhile, the researchers say vitamin E may play a role.
They note that past studies from the same Chicago group have linked vitamin E to slower decline in mental function.
Vegetables contain more vitamin E than fruits, and veggies are more likely to be eaten with fats -- including salad dressing -- that help the body absorb vitamin E, according to Morris' team.
Researchers' Shopping List
Ready to eat more vegetables? Here are some of those listed in the study survey:
- Tossed salad
- Greens (such as mustard and turnip greens)
- Cabbage in coleslaw
- Lima beans
- Beans, lentils, soybeans (legumes)
- Carrots (cooked or raw)
- Sweet potatoes
- Summer squash
But the data did include participants' vitamin use.
People who consume 2,000 calories per day should eat two cups of fruit and 2.5 cups of vegetables daily, according to the U.S. government's Dietary Guidelines for Americans 2005.
For instance, six baby carrots are half a cup. A small apple is a cup.
A cup of raw, leafy greens actually counts as half a cup of vegetables. So to make a salad that provides a one-cup veggie serving, toss a cup of lettuce with a half a cup of other vegetables.
The government's guidelines recommend eating a variety of fruits and vegetables daily.
A simple method is to "eat your colors," picking fruits or vegetables from every hue in the rainbow.
Here are some vegetables for each color, noted on the nonprofit Produce for Better Health Foundation's "5 A Day the Color Way" Web site.
- Blue/purple: Purple cabbage, eggplant
- Green: Spinach, broccoli, green beans
- White: Cauliflower, garlic, onions
- Yellow/orange: Carrots, yellow squash, sweet potatoes
- Red: Beets, red peppers, tomatoes
SOURCES: Morris, M. Neurology, Oct. 24, 2006; vol 67: pp 1370-1376. U.S. Deparment of Health and Human Services and U.S. Department of Agriculture: "Dietary Guidelines for Americans 2005 -- Key Recommendations for the General Population." 5ADay.gov: "What Counts as a Cup?" 5ADay.org: "5 a Day the Color Way." News release, American Academy of Neurology.
By Miranda Hitti
Reviewed by Louise Chang