Q: I have a friend who seems to succumb to advice from the health-food store. Recently she bought a supplement containing something called bioflavonoids. Are they of any value?

A: In a word, no. Bioflavonoids, once known as vitamin P, are a group of naturally occurring compounds, the first of which was isolated from citrus rind about 50 years ago. Studies conducted at that time indicated that citrin, as it was called, decreased the fragility of tiny blood vessels and heightened the effectiveness of vitamin C in treating guinea pigs for scurvy. That observation led to the suggestion that citrin and other bioflavonoids might be useful in reducing hemorrhages in hypertension and other diseases.

The results of the original experiments were never duplicated. Nonetheless, over the years bioflavonoids have been suggested as treatments for everything from retinal hemorrhages to the common cold. In fact, no nutritional function or therapeutic use for bioflavonoids has ever been demonstrated. Logically, then, there is no reason to take them as nutritional supplements.

I have read conflicting advice about whether it is possible to freeze cheese. Can you tell me?

A: Cheeses can be frozen, but how long they can be stored before deterioration will vary. Specific data on the length of time different cheeses will keep is sparse. According to one study, cream cheese showed no quality loss after six months, while cheddar began to lose color and undergo texture changes after just six weeks. But while it became crumbly and difficult to serve, it was still fine for use in cooking.

Q: My 9-year-old daughter is a bit overweight. After school closed in June, she put herself on a reasonable diet and slowly shed a few pounds. The pediatrician said she is doing just fine and that, given her expected growth, all she needs to do is maintain her current weight and she will have the problem under control. Now that fall is back, my concern is school lunches. She really wants to buy her lunch as all her friends do. But some of the menus are high in calories. Should I forbid her to buy lunch and go back to packing it myself?

A: That's probably not necessary. In fact, some schools offer low-calorie options on days when the menu contains too many calories for children who must watch their weight. If your school doesn't offer this choice, consider suggesting that they start doing so. Your daughter is not the only student who is concerned about her weight.

Even if this is not feasible, your daughter can continue to buy her lunch at school. She will benefit from the opportunity to make wise choices on her own. If she can learn to do it, she will have made great strides in gaining independence and in harnessing her weight problem.

To get her started, it might be a good idea to review the week's menus, which are sometimes printed in the local newspaper or sent home. Together, you can decide how to choose lower-calorie foods from available options. She can ask the person serving to leave the gravy off her turkey or to omit the french fries. If both green beans and peas are offered, she can choose the beans, and she can eat a sandwich "open-faced," reserving the calories from the extra slice of bread for an after-school snack. As a beverage, she will probably want to choose skim milk.

And by now, she must know that if it is available, fresh fruit is the preferred choice. If, on the other hand, canned fruit is served, she will want to leave the syrup (a source of nothing but calories) in the dish. If sweet desserts are the only option, bring a piece of fresh fruit from home -- or wait until she gets home and have it as a snack.

One situation may make it necessary to resort to carrying lunch at least some of the time. In schools where prepackaged meals are served, some of the menus may not fit with your daughter's attempt to restrict her lunch-time calories. Again, by checking the week's menu, you may be able to send along replacements for foods too high in calories to fit into her diet plan.