Eating Enough Dark Veggies?

Your mother always told you to eat your carrots--they were good for your eyes. Now she may start nagging you to eat just a few more.

A panel of researchers from the Institute of Medicine said last week that a new review of recent research shows that dark vegetables--such as carrots, sweet potatoes and broccoli--provide the body with only half as much vitamin A as previously thought--meaning consumers must be sure to eat enough of these, especially if they shun meat and fortified milk.

“Darkly colored fruits and vegetables are still good sources of vitamin A,” said Dr. Robert Russell, professor of medicine at the Tufts University School of Medicine, who chaired the panel. “But new evidence shows that it takes twice as much of them to yield the same amount of vitamin A in the body as we previously understood.

“This doesn’t mean fruit and vegetable consumption must double,” he added. “Follow the five-a-day rule, and think ‘dark’ and you’ll be fine.”

He was referring to the government’s campaign in recent years to encourage Americans to consume five servings of fruit and vegetables, and stressing that the most nutrient-rich produce is darkly colored. “Generally, the darker the color, the more vitamin A activity,” he said. “If you pick noncolored vegetables, you’ll have a hard time.”

A sufficient serving would mean a half-cup cooked or a full cup raw five times a day, “and if you pick carrot or pumpkin, you can do it with one [serving]” because those two are loaded with the nutrient, he said.

The panel emphasized that strict vegetarians are regarded as most at risk for the consequences of vitamin A deficiency--which include impaired vision and dry, scaly skin-- because they generally avoid meat and fortified milk, which also contain plenty of vitamin A.

The Institute of Medicine, part of the National Academy of Sciences, has been reviewing and revising U.S. guidelines for the intake of vitamins and other nutrients; this was the fifth in a series of such reports.

The group also revised slightly downward its recommendations for iron, saying men and women past menopause risk accumulating too much in their bodies; research has suggested a possible link between elevated iron stores and a higher incidence of heart disease and cancer.

Men and women past menopause need only 8 milligrams a day of iron, while premenopausal women should get 18 milligrams a day and pregnant women 27. No one should consume more than 45 milligrams a day, the report said.

The committee raised slightly the recommended intake of vitamin K, found in leafy green vegetables and important for ensuring that blood clots properly. The recommended intake for men is 120 micrograms and, for women, 90 micrograms.

It said men and women should get 900 micrograms a day of copper and 150 micrograms of iodine. Men should get 35 micrograms of chromium a day, and women should get 25.

The institute reiterated the standard advice that foods can provide sufficient nutrients and that supplements were not needed.