Veggies Lose Nutrients in the
An article from the Oct.
16, 2003 issue of the "HealthDayNews" reports on new research that shows
different ways of preparing, storing and processing vegetables can affect
how good they are for you. The data for this article came from two
studies that appeared in the November issue of the Journal of the Science
of Food and Agriculture. The studies report that several different
processing procedures and cooking can reduce antioxidants, which are
cancer-fighting compounds, normally found in vegetables.
are plentiful in vegetables and work to eliminate free radicals, which can
damage cell DNA and contribute to various diseases. That's why eating
fiber, fruits, and vegetables, all of which contain antioxidants, can help
prevent cancer and cardiovascular disease.
One of the studies showed that broccoli, for
instance, lost 97 percent of flavonoids, 74 percent of sinapics and 87
percent of caffeoyl-quinic derivatives (three different types of
antioxidants) when it is zapped in the microwave. When boiled the
conventional way (i.e., not in a pressure-cooker), broccoli lost 66
percent of its flavonoids; when tossed in a pressure cooker, it lost 47
percent of its caffeoyl-quinic acid derivatives. Steamed broccoli, on the
other hand, lost only 11 percent, 0 percent and 8 percent, respectively,
of flavonoids, sinapics, and caffeoyl-quinic derivatives.
Cristina Garcia-Viguera, lead author of the
research paper noted that the advantage of steaming vs. conventional
boiling is that you're "Not using water directly in contact with the
vegetable. The nutritional compounds don't go into the water. Once the
compounds are in the water, the temperature destroys them much easier."
The damage from a microwave occurs because it heats the inside of the
vegetable. That, combined with the fact that you normally use water when
microwaving, can cause the destruction of the valuable nutrients.
Vegetables that are blanched before freezing (a
common processing technique) can lose up to one third of their
antioxidants. Frozen storage can also cause losses, though these losses
are much smaller.
Samantha Heller, a senior clinical nutritionist at
New York University Medical Center in New York City states that not all of
the healthy properties of vegetables are being eliminated. "You're still
getting plenty of healthy compounds as well as fiber, so there's
absolutely no reason not to eat vegetables -- although, of course, the
fresher the better." She goes on to say, "If people are willing to have
vegetables anyway, shape or form, even if they are going to nuke then, I'd
rather have them do that."