The next time you're whipping up
dinner you may want to boil, steam or stir-fry your vegetables. Eating cooked
vegetables -- and even a few fruits -- appears to increase your iron intake,
according to research presented here at the national meeting of the American
Chemical Society.
Although the amount of iron in a vegetable remains unchanged, cooking makes
more of that iron available for absorption by the body, explained Tung-Ching
Lee, a food scientist at Rutgers University in New Brunswick, New Jersey. Lee
presented the findings at the American Chemical Society meeting here.
For example, cooking increases the available iron in cabbage from about 5%
to 15%, and in broccoli from 6% to more than 30%. In comparison, the amount of
iron that can be absorbed from red meat is 25%.
The fruit that benefited most from cooking was peaches, although kiwi was
found to have the most available iron in its fresh form, Lee said. In general,
fruits are not a big source of iron.
Lee tested 48 vegetables in all, purchased fresh from retail groceries in
Taiwan, and found that 37 of the 48 benefited from cooking for approximately 15
minutes.
Some vegetables benefited dramatically while others, such as spinach, are
equally nutritious whether raw or cooked.
Lee also discovered that storing cooked vegetables overnight, even under
refrigeration, results in dramatic losses in the available iron content. So to
get the most out of your veggie meal, "you need to consume it fresh cooked," he
said.
Cooking tomatoes with other vegetables also enhances the nutritional value
of the other vegetables, such as broccoli and cauliflower, Lee added. Blending
vegetables after they are cooked leaves the iron availability unchanged, but
blending vegetables before cooking will lower their iron availability almost to
that of the raw form.
Cooking enhances the body's ability to absorb the iron because in plants,
iron is stored as ferritin, a compound that releases its iron when it is heated.
Blending before cooking disrupts the cell walls of the plant and interferes with
this process.
Iron deficiency anemia is the most prevalent nutritional problem in world
today, Lee said in explaining his motivation for this research.
