DEAR DR. BLONZ: Could you give me some information, and your opinion, on DHEA being promoted as an anti-aging hormone? I'm a nurse of 26 years and a nutritionist, and have heard very little information on this. -- S.T., Phoenix

DEAR S.T.: DHEA is the abbreviation for a hormone with the tongue-twisting name dehydroepiandrosterone. It is made by the adrenal glands, which sit on top of the kidneys. DHEA, while a hormone itself, serves in the formation of a number of other hormones, including estrogen, testosterone and adrenaline.

Popular interest in DHEA stems from some recent research that has connected higher levels of DHEA with a lower risk of some age-related problems. There was encouraging research in experimental animals, but research using people is limited and inconsistent at best. Despite this, the idea took shape that DHEA might be a miraculous fountain-of-youth "drug." Before you knew it, DHEA supplements began to appear in health food stores and as a keystone product in some multilevel marketing enterprises.

Anyone who is considering DHEA should speak with their physician. It is important to appreciate that DHEA is not a vitamin or a mineral; it is a powerful medicine -- a hormone that can bring forth undesirable as well as desirable effects. This is especially true if the levels used in the animal studies were to be scaled up for our larger bodies. For example, those at risk for prostate cancer could, by taking DHEA, be increasing the amount of testosterone in the body -- the very hormone associated with the spread of prostate cancer.

Our level of naturally produced DHEA decreases as we age, but that does not mean that providing more will reverse the effects of aging. Let's face it: We currently know very little of what DHEA can do, whom it may help and whom it may harm. Until more research is done, taking DHEA is nothing more than a risky roll of one's hormonal dice.

DEAR DR. BLONZ: There are definite concerns about heart disease in our house. Please settle a dispute: Does removing the skin from chicken before you eat it get rid of the cholesterol? -- F.F., San Jose, California

DEAR F.F.: No. Although there is a small amount of cholesterol in the skin and fat of a chicken, most is found in the light and dark meat. This holds true for beef, pork and lamb, as well. And buying leaner cuts does little to reduce the cholesterol.

I would not be that concerned, as research indicates that our intake of dietary cholesterol is not as much an influence on blood cholesterol as is the overall quality of the diet. Keeping your intake of fat to less than 30 percent of your calories, and making sure your diet is balanced with a good proportion of fruits, vegetables, grains, nuts and seeds, are the best dietary ways to move toward preventing heart disease.

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: A tomato carton at a local produce market stated that the tomatoes contained a number of "non-tomato ingredients." It listed petrolatum, paraffin, carnauba wax and food-grade mineral oil. The carton also stated that the fruit had been treated with ortho-phenylphenol to inhibit mold. Are these substances in or on the tomatoes, and are they dangerous to eat? -- P.P., Vallejo, California

DEAR P.P.: Petrolatum, paraffin and carnauba are different types of waxes. Produce growers apply waxes to their fruits and vegetables to retain moisture, slow flavor loss, enhance appearance and prevent mold during packing, shipping and selling. Petrolatum and paraffin are byproducts of petroleum (oil). Carnauba, which comes from the wax palm of Brazil, is also used in car wax.

Waxes are applied to a wide variety of produce, including tomatoes, apples, bell peppers, avocados, cucumbers, sweet potatoes, citrus fruits, peaches, pumpkins, eggplants, squash and hardshell nuts. Waxes are only used in small amounts, and are not considered harmful. Experts estimate that one pound of wax will cover 160,000 pieces of produce.

One potential cause for concern with waxes stems from the possible presence of pesticide and fumigant residues on the surface of the produce before the wax is applied. (In some cases, the pesticide or fumigant is mixed with the wax.) Ortho-phenylphenol is a type of anti-mold fumigant that's often used this way.

Chemicals cannot be washed off if embedded in a wax, but the health risk posed by the presence of such wax-bound pesticides or fumigant residues should be minimal if the chemicals are applied according to regulations. And, of course, it's only an issue for produce in which the skin is consumed.

Although you can try scrubbing these waxes off, it takes more than water to do the trick. A mild detergent, or products that claim to clean the wax off of produce (available at natural food stores) may be helpful. Without these, the only real way to "de-wax" the produce is to take off the peel.

It is important to understand that both conventional and organic growers can apply waxes as a protectant before shipping. All waxed produce should be labeled as such. Organic growers' waxes come from natural sources and do not contain any synthetic pesticides or fungicides. The presence of waxes is yet another reason why it's always best to consume a variety of fruits and vegetables, and change your selection with the seasons, rather than eating the same foods all the time.

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 there any nutritional advantage to goat's milk over cow's milk? What about those who are allergic to cow's milk, or who are lactose-intolerant? -- T.R., La Jolla, California

DEAR T.R.: All things considered, it is a bit of a wash. Goat's milk has a bit more protein, fat, potassium, calcium and magnesium than cow's milk, and even a small amount of vitamin C. But there is less vitamin B12, folate, selenium and riboflavin.

There are differences in taste, but most people are able to digest cow's milk and goat's milk with equal ease. A few may find the softer curd of goat's milk easier on the stomach. Both milks have comparable levels of lactose, but because they are from different animals, their proteins will not be identical.

If you are thinking of trying goat's milk because you're allergic to cow's milk, start with a small amount. There have been cases, especially in young children, of cross-reactions among different types of milk. In other words, a child with an allergy to cow's milk may also react to goat's milk, even without any previous exposure to it.

DEAR DR. BLONZ: When you fry or scramble your eggs, do you destroy more protein than if you were to poach them? I have heard this and wonder if it is true. Also, what goes on during the cooking of the egg white? -- G.G., Berkeley, California

DEAR G.G.: Bottom line first: As long as you do not overcook your eggs, there is no evidence that frying or scrambling will destroy significantly more protein than poaching.

As for egg whites: They are a great source of high-quality protein. Think of individual protein molecules as long chains of amino acids; when viewed three-dimensionally, those in an egg are folded among themselves like crumpled strips of paper. Raw egg white is almost 90 percent water by weight, and the proteins are suspended in the clear, viscous liquid.

When heated, protein globules tend to uncoil a bit. This step helps our digestive process, as it makes it easier for our protein-digesting enzymes to get at the protein and break it into individual amino acids -- a necessary step prior to absorption. Heated egg proteins begin to interconnect, and when this happens, the egg white becomes solid and opaque. Water remains at first, but as more and more heat is applied, the water eventually gets squeezed out and the egg white takes on a harder, eventually rubbery, texture.

The idea, of course, is to cook the egg without overdoing it. Poaching takes place at or below 212 degrees F, the boiling point of water. Frying takes place at higher temperatures: at or slightly above 250 degrees F. Excessive heat from overcooking can destroy any protein. It makes sense that there would be a greater risk of overdoing it with frying or scrambling than with poaching, but the temperatures at which eggs are normally prepared would not be high enough to cause any significant protein destruction.

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.