DEAR DR. BLONZ: The calcium supplement sold at my local pharmacy is oyster shell calcium. I recall reading that there is something wrong with this form, such as that it used to contain some kind of contaminant, but I cannot remember the specific problems. Is this form now safe? - M.A., San Diego, Calif.

DEAR M.A.: Calcium supplements from natural sources are the ones at higher risk for lead contamination, mainly because they tend to form in areas where lead is also hanging around. These sources include oyster shell, dolomite and bone meal. Oyster shell calcium becomes a problem when the oysters have been in lead-contaminated waters. Dolomite, also called dolomitic limestone, is a mined mineral that's composed primarily of calcium carbonate and magnesium carbonate, plus some other elements. If the mineral happens to be in areas that contain elevated amounts of lead, this "natural source" would also have its share of that unwanted mineral. Bone meal makes sense as a

calcium supplement because, in addition to the calcium, it contains the other trace elements used to make bones. The problem is that bones are often a storage tissue for heavy-metal contaminants. Animals allowed to graze near sources of industrial pollution can become sources of higher-than-normal levels of these contaminants in their bones and other tissues.

This doesn't mean that all natural sources of calcium are contaminated. It simply means that when you choose a calcium supplement made from any of these compounds, you need to check the source and opt only for those brands that state that their product is low-lead or lead-free, or bears any other testing you need to be comfortable prior to purchase.

DEAR DR. BLONZ: A friend of mine sent me an article from a San Diego newspaper that contained your comments about the problems with taking fish oil capsules while on Coumadin. I have been diagnosed with chronic deep vein thrombosis that requires medications to adjust how my blood clots. As a result, I have been on Coumadin for many years. I read your article with interest, but I question the last sentence as follows: "Once the dose is decided upon, you don't want to introduce factors that can ruin that recipe." The key requirement for me is to maintain my clotting within a narrow margin. As it was explained to me at the Coumadin clinic, "You select your diet and we will adjust your Coumadin dosage." For me, the goal is to reduce my need for Coumadin, and if I can do that by taking garlic, flaxseed oil, olive oil, vitamin E and fish oil, then that's the way I want to go! The less of this drug I put into my body, the happier I'll be! Is there a problem with that philosophy? - R.R.,

no city or state given

DEAR R.R.: I have no problem whatsoever with your philosophy. The key is consistency, and that translates into making consistent decisions regarding dietary components that can affect clotting. This, however, is after your Coumadin dose is set. If you want these components to be a part of the formula, that's great. Keep your physician and the clinic informed and make sure they know this is the way you will be eating. Follow their lead as to how long you would have to eat this way before its effect on clotting is normalized. Your monitoring will pick up any trends indicating a need for adjustment. Rely on the guidance of those handling your health care, and you can have your Coumadin and eat your desired foods, too.

For those in need of assistance integrating this new dimension into their life, check out "The Coumadin Cookbook" (Marsh, 2003) by Rene Desmarin, M.D.

Send questions to: "On Nutrition," Ed Blonz, c/o Newspaper Enterprise Association, 200 Madison Ave., New York, NY 10016. For e-mail, address inquiries to: ed@blonz.com. Due to the volume of mail, personal replies cannot be provided.

Ed Blonz, Ph.D., is a nutrition scientist and the author of "Power Nutrition" (Signet, 1998) and the "Your Personal Nutritionist" book series (Signet, 1996).

Copyright 2005, Newspaper Enterprise Assn.