I read that drinking water may contain a lot of lead. How can I find out about the lead level in my water?

ANSWER - To obtain a lead test, the first step is to locate a qualified laboratory. The Environmental Protection Agency (EPA) Hotline at 1-800-426-4791 will provide you with the phone number of the office in your state that certifies the laboratories. Some state labs do the analysis themselves. It may be possible to take care of the whole thing by mail.The laboratory will give you instructions for collecting the sample, and may even send a bottle for you to fill and send back. Usually the test costs no more than $20, and results take a couple of weeks. It's crucial to follow instructions carefully to get results that accurately reflect the lead level of your own water.

At present, the legal limit for lead is 50 parts per billion. However, because of some concern about the potential dangers of lead exposure, the EPA has proposed tightening the regulation. One way to reduce lead levels is simply to let the water run for several minutes until it becomes as cold as possible before drinking it or using it in food preparation. Certainly this raises the issue of wasting water, especially in areas plagued by drought. In that case, the sensible thing is to catch running water in a bucket and save it for other uses. And if you collect the day's drinking water all at once and store it in the refrigerator for later use, the process of flushing out the lead can be held to a minimum.

QUESTION - It's often said that elderly people living alone havepoorer diets than those who live with someone. Is that really true, or is it just a myth?

ANSWER - For some groups of the elderly, it does appear to be true, though the explanation might surprise you. Rather than consuming a poorer diet because they subsist on nothing but tea or toast, the problem is that they simply eat less food. The foods chosen are nutritionally comparable, but not eaten in sufficient quantity.

This information comes from Maradee A. Davis and her colleagues at the University of California at Berkeley. Using three-day intakes obtained from the 1977-78 National Food Consumption Survey, they classified diets of those 55 and older into two groups: either poorer or higher quality. The rather broad classification was based on whether an individual had consumed less than two-thirds of the RDA for five of nine nutrients, including vitamin A, C, B-6, B-12, thiamin, riboflavin, iron, calcium, and magnesium.

Overall, 13 percent of the participants' diets were classified as poor. Most striking was the finding that 25 percent of men 75 and older living alone consumed diets ranked as poor. Close behind, 22 percent of the women in the age range 55 to 64 who lived alone also subsisted on inferior diets. And in general, poor diets were more likely to be found among women than among men living alone.

As stated, what made the difference was not the nutritional quality of the foods consumed, but the number of calories taken in. That is, poor diets were more likely to be found among those who ate less.

Although the data used are now over 10 years old, there is little reason to think the picture has changed.

QUESTION - My daughter is a vegetarian. She insists that certain algae provide all the vitamin B-12 she needs, but I recall reading that there are questions about whether that's true. We agreed to settle the dispute by asking you for the latest information. Please tell us: Is what she's doing safe, or should she be taking a B-12 supplement?

ANSWER - Current data suggest that relying on algae for B-12 is unwise. The latest evidence against the practice comes from a study conducted in the Netherlands and recently reported in the American Journal of Clinical Nutrition. The investigators analyzed a number of foods thought to have B-12 activity. Of these, just two algae, nori and spirulina, appeared to have B-12. Yet when used by a small group of children from strict vegetarian families as a source of B-12, it did not behave like the true vitamin. That is, when blood levels of the vitamin rose, it did not fulfill its job of helping to build red blood cells. Exactly why remains a matter of conjecture. One possibility is that the vitamin does not come in a form the body can use. Alternatively, it might be that these algae also contain compounds that hinder its activity.

Whatever the explanation, the important point is that vegetarians should take a supplement known to contain B-12 in a form the body can use.

QUESTION - Does the size of a turkey affect the fat content and consequently the caloric content of the meat?

ANSWER - Differences both by size and type of bird are too small to be of practical importance. In white meat, the range of difference in a three-ounce portion is a mere 20 calories. Three ounces of fryer-roaster meat without the skin provides 120 calories, while a similar serving of tom turkey has 130 calories, and of hen turkey, 140 calories. With dark meat, three ounces of fryer-roaster has 140 calories; the same amount of tom turkey contains 160 calories, and of hen turkey, 165 calories.

If you're being extra careful about counting calories, it's probably far more important to use a kitchen scale to weigh your food, thereby eliminating the possibility of overestimating portion sizes, than it is to worry about the type of turkey you prepare.

1991, Washington Post Writers Group