DEAR DR. BLONZ: My daughter has been having heavy periods, and she also has iron-deficiency anemia. She told me she takes oral contraceptives, but these do not seem to be helping much. What iron supplement would you recommend? -- N.N., Portland, Ore.

DEAR N.N.: Heavy periods are not unusual, especially in teens who are not yet ovulating regularly and in women approaching menopause. Having said that, I am not a medical doctor, as you know, so keep in mind that other factors can be involved. If your daughter routinely experiences heavy periods, especially those that last longer than a week, it would be wise to have her check with her physician or gynecologist. Do this before you resort to iron supplements.

As for iron, the most efficient way to get it into the body is through food. The body does not efficiently absorb dietary iron, the one exception being the heme iron that is present in meats. Assuming she is not a vegetarian, a reasonable first step would be to include lean meats in your daughter's diet.

In terms of supplements, iron comes in two forms: ferrous and ferric. Of the two, the ferrous form is better absorbed, and it tends to be less irritating to the stomach.

The difficulty with iron supplements is that iron doesn't dissolve easily, and it must be in solution before it can be absorbed. Studies have shown iron supplements tend to work best when they are taken with a glass of orange juice on an empty stomach. This can be a problem for some, however, because iron supplements may irritate an empty stomach.

Whenever your daughter takes her iron pills, try to include acidic foods such as citrus juices or tomato sauce. Even a vitamin C (ascorbic acid) pill will help. The presence of the acid helps to get the iron into solution and maximize the amount your body will absorb.

As all this being said, I want you to be very aware that excess iron intake can be dangerous. Do not start your daughter on iron without first consulting her physician, and make sure that you keep all supplements out of the reach of children.

DEAR DR. BLONZ: What is the difference between a vegetable and a fruit? Also, I'm interested in becoming a certified dietary manager; what are the requirements for this, and how would I go about getting certified? -- S.F., Richmond, Calif.

DEAR S.F.: A vegetable is an edible part of a plant with a soft stem, including leaves (lettuce), roots (carrot), bulbs (garlic), stalks (celery), seeds (peas), tubers (potato) and flowers (cauliflower). A fruit is the mature ovary in a flowering plant -- that fleshy part of the plant that contains the seeds. This means that tomatoes, eggplants, peppers and squashes are technically fruits, even though they are commonly thought of as vegetables.

As for your interest in becoming a certified dietary manager, there are a number of resident and correspondence schools for this field. Once you have the credentials, there are career requirements and a nationally recognized credentialing exam involved with gaining and maintaining certification. For more information, contact the Association of Nutrition and Foodservice Professionals (anfponline.org).

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.

DEAR DR. BLONZ: Is folate the same as folic acid? I read about the importance of folate, but when I look at the label of my multivitamin, it says "folic acid." -- S.I., San Diego

DEAR S.I.: They are both the same. Throughout its history, the vitamin we call folic acid or folate has gone by many names, including Wills Factor, anti-anemia factor, SLR factor, PGA, factor U and factor R, not to mention vitamins M, Bc, U, B9, B10 and B11. The explanation is that many different laboratories were doing research on the same substance at the same time, and many were working on related compounds that had the same vitamin activity.

Folate, it turns out, is a generic term referring to a family of related compounds, the simplest of which is folic acid. We usually don't find folic acid in nature; instead, we find one of the folates, which you can think of as being forms of folic acid with different lengths of a particular side chain attached.

Folate is usually associated with food, therefore, while folic acid is usually associated with supplements. Folic acid appears to be a key compound in human nutrition. The increasing frequency of articles on the benefits of folate reflect the fact that an inadequate intake of this nutrient is now being associated with a number of different ailments, including heart disease and certain birth defects. What's of interest here is that you don't need megadoses to avoid problems. One can get all the folate they need from a healthy diet. Good sources include green leafy vegetables, organ meats, legumes, orange juice, beets, avocado and broccoli.

DEAR DR. BLONZ: I had been in search of the perfect fancy butter dish, and I just found one at an estate sale. I learned that it is made of leaded crystal (24 percent lead), and when showing off my dish to a friend, she told me about your column on leaded crystal. Are you saying that I should pitch this new treasure -- or at least not put any butter on it and then into my digestive system? I only want to use it as a serving dish, but not if it's going to poison my body. -- M.B., Danville, Calif.

DEAR M.B.: Lead is a toxic substance, and the risk with this type of crystal is that the lead is not tightly bound. When in contact with liquids (water or alcohol), small amounts of the lead can slowly dissolve or leach into the liquid. Dried grains would not be an issue -- not that many would choose to store rice or whole wheat in leaded glass. Butter is primarily fat, but it does contain a small amount of water (as does margarine). There would be negligible risk to using your leaded crystal as a serving dish, so go ahead, enjoy, and congratulations on your find.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.

DEAR DR. BLONZ: I was shopping for an upcoming party and considered purchasing grated cheese to save prep time in the kitchen. I have gotten into the habit of reading the labels of any packaged foods that I buy, and this one gave me pause. I know that fresh cheese is usually made from some type of milk along with salt and enzymes, but the package of grated cheese listed natamycin as an ingredient. I have no idea what that is. There was also powdered cellulose listed, which is a bit more familiar, but I am not certain why it is required either. Are these things I need to be concerned about? -- N.Z., via email

DEAR N.Z.: Finding unknown ingredients on your food labels can be troubling, especially if they have imposing-sounding names. It's easy to become concerned that something unwholesome is in the package. Ingredients -- even entirely wholesome ones -- often sound more onerous than they actually are, and in this case, there is little cause for concern.

When cheese is grated, there is a great increase in surface area, and with this increased area comes more space for unwanted molds or yeasts to grab on and make themselves at home. The natural moisture present in cheese can also create a friendly environment. Grated cheeses are usually packaged under a controlled atmosphere to inhibit the growth of such organisms, but that would not prevent them from being introduced and growing after the package is opened.

Natamycin is a naturally occurring preservative compound that helps prevent the growth of undesirable molds or yeasts. It is often used with cheeses because it doesn't work against the friendly bacteria that are essential for flavor development during the ripening process. You can find products that don't contain this preservative, but it is doubtful that it is cause for concern. It, along with the protein in the cheese, will be denatured and destroyed during the digestive process.

The powdered cellulose, a naturally occurring carbohydrate from plants, is there to prevent the grated cheese from clumping together. Cellulose, which is not digested, is the most plentiful carbohydrate substance in nature. It is actually considered to be dietary fiber, but such a small amount is needed for anti-caking purposes that the fiber won't even register on the nutrition label.

Regarding food additives in general, you can limit the problem by sticking to whole or minimally processed foods, but even this is no guarantee. As a group, food additives are a mixed lot, containing a variety of substances that accomplish some rather amazing things. They are all chemicals -- one and all -- but the same can be said for all foods, whether they come fresh from the garden or from a package on the shelf.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.