Evelyn Tribole, RD
The USDA Dietary Guidelines for Americans 2005 recommends that most
Americans get six ounces of grains daily, and that half of that — at least three
one-ounce servings (one slice of bread equals about one ounce)– should be
from whole-grain sources. Of course, eating only whole grains to meet the
quota is even better.
Breads can be a source of whole grains, but knowing which ones are most
healthful is difficult. Bottom Line/Health spoke to nutritionist Evelyn Tribole, RD,
Whole versus refined
Grain products, including pasta, oatmeal, hot and cold breakfast cereals and bread, are
divided into two subgroups — whole and refined. Whole grains, by definition, contain
the entire grain — the bran (outer coating), germ (seed embryo) and endosperm
(also called the kernel, it makes up most of the seed). Examples include whole-wheat flour,
cracked wheat (bulgur) and brown rice.
Whole grains are rich in fiber, which has been shown to reduce risk for heart disease, diabetes
and some cancers. They provide large amounts of vitamins and minerals that are sometimes
lacking in our diet, including magnesium, selenium, potassium, zinc, vitamin E and chromium.
Refined grains are milled to remove the bran and germ, which gives them a finer texture and
lengthens their shelf life. This process is also nutritionally devastating — it removes the healthful
fiber, iron and many B vitamins and other vitamins and minerals found in whole grains.
Since refined grains are digested more quickly than whole grains, they can cause spikes in blood
sugar and insulin secretion, which can increase hunger and diabetes risk. Refined grains include
white flour, white rice and white bread.
(Part #2 to follow)