Q: Does a person's blood type indicate the type of diet he or she should follow?
A: No. You may have heard of a diet based on the idea that blood type indicates whether your genetic ancestors were hunters, farmers or nomads. This in turn tells you whether you should eat meat, chicken, dairy foods, etc. Supposedly, eating appropriately for your blood type helps control weight while preventing cancer and other health problems. Although reports of such a diet may include vague references to someone's "research," no research supporting such claims has appeared in a scientific journal where it could be reviewed by experts.
Any weight loss that results from such a diet is probably due to the menus prescribed by the diet. These menus often contain calorie levels that are quite low, and many foods are restricted. Most experts agree that long-term weight control is best achieved by unrestricted access to a variety of foods, with emphasis on portion control, nutritional balance and regular exercise.
As for cancer prevention, a landmark report from the American Institute for Cancer Research concluded that a diet that emphasizes fruits, vegetables, whole grains and beans is the best approach.
Q: Is corn considered a vegetable or a grain?
A: Botanically and nutritionally speaking, corn is a grain. Corn is more concentrated in starch (carbohydrate) and calories than true vegetables such as broccoli, cucumbers and green beans. Sometimes people who have trouble controlling their weight or blood sugar have been building too much of their meals around starchy foods, including potatoes, bread and starchy vegetables, without including abundant servings of green, red and orange vegetables. Corn is a good source of dietary fiber since it retains all three of its primary layers.
Q: Does the manner by which powdered infant formula is prepared affect its safety?
A: Yes. A survey reported recently in the Journal of the American Dietetic Association found that mothers commonly made several errors in preparing their babies' formula that could pose safety hazards. One-third of mothers routinely mixed formula using warm tap water. Warm tap water can contain lead that leaches out of plumbing pipes. This could result in lead toxicity and affect brain development.
About 15 percent of mothers in the survey left prepared baby bottles standing at room temperature for more than two hours. This encourages growth of bacteria that can cause diarrhea.
Up to 48 percent of mothers heated bottles in a microwave oven. This is discouraged because microwaves heat food unevenly, potentially causing hot spots that you may not detect when you test the temperature. To protect babies' mouths from burns, experts advise place the bottle of formula in a pan of warm water until it reaches the right temperature.
Karen Collins is a nutritionist with the Washington, D.C.-based American Institute for Cancer Research.
