DEAR DR. BLONZ: There is a chelation dietary supplement product that I am interested in to help lower my risk of heart disease. I now take a statin for this same purpose. Is oral chelation effective? And if so, how long do you have to take the supplements? -- S.F., Las Vegas

DEAR S.F.: Chelation is indeed a therapeutic technique that has been investigated for heart disease, but that research involves an intravenous (IV) infusion -- not a dietary supplement. (More on that later.)

The concept of chelation relates to the ability of a substance to bind, or chelate (KEY-layt), other compounds and stop them from reacting or causing harm. One main substance used is EDTA, short for ethylenediaminetetra-acetic acid. This is the same substance in the lavender-topped test tubes used when you go in for a complete blood count: The EDTA in those tubes chelates the iron in your blood and prevents it from clotting.

EDTA is very poorly absorbed when taken by mouth. After you swallow it, the EDTA has no choice but to travel the entire length of the digestive tract, its binding ability intact. There have been medical uses of oral EDTA to bind toxic intakes of unwanted heavy metals, such as mercury, arsenic, lead, cadmium or iron, that were inadvertently consumed. In such cases, it must be noted that the EDTA can also bind essential minerals, such as calcium and manganese, and escort them out of the body before they might be absorbed. There is no way to “direct” the EDTA to grab only toxins or certain unwanted substances. Therefore, oral EDTA should be limited to specific uses under medical direction.

The administration of EDTA directly into the bloodstream via an IV bypasses the poor-absorption issue. Intravenous chelation therapy has legitimate uses in systemic heavy metal poisoning, metabolic conditions where minerals accumulate, or diseases where access to certain minerals is key to the progress of the disease.

Your question, however, relates to oral chelation for heart disease. I was unable to find any competent and reliable evidence to support the safety and efficacy of oral chelation therapy for heart disease. As I mentioned above, there was a study looking at this issue: The National Institutes of Health helped fund a major clinical trial using an IV infusion of EDTA to determine if it might have some application to heart disease.

Referred to as TACT (Trial to Assess Chelation Therapy), the study did report a beneficial effect, but only for patients with diabetes. I want to point out, again, that this is EDTA given in an IV, not taken orally. You can read more about this use of chelation at nccih.nih.gov/health/chelation.

At the bottom of that page is a link regarding the FDA’s issuance of warnings to marketers of over-the-counter oral chelation products, and the dangers and false claims associated with such products.

Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 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 have a follow-up suggestion to the recent column on storing bread in the freezer. Like the previous letter-writer, I live alone, and I like to cook and freeze leftovers in single-serving portions. With my bread, I usually double-wrap the loaf: I put the original package in one of the larger plastic sleeves that come with the daily paper, then twist-tie it shut after making sure all the air is out of the bags.

Now for my question: Does freezing milk affect its quality or safety? I balk at paying almost as much for a quart of milk as I do for a gallon. I have a lot of freezer space, and have been freezing milk in quart mason jars. I’m especially careful to leave at least two inches of space at the top, between the milk and the lid, to allow room for expansion of the liquid as it freezes. If you violate this principle, I’ve learned, the glass jar is likely to crack. Is milk safe to drink after having been frozen and then thawed slowly in the refrigerator? -- J.W., Tucson, Arizona

DEAR J.W.: Your bread-freezing technique sounds great. It is always gratifying to find second-generation uses for the serviceable plastic bags that come into our possession.

Freezing is a safe and acceptable way to store milk. Changes in nutritional value are negligible, but there may be a few minor changes in the way the milk appears and tastes. The freezing process can cause a breakdown in the homogenization, which is the process that distributes the milk fat evenly throughout the milk. Of course, this will not be an issue with nonfat milk; with other types, however, an occasional drop of fat may be seen floating around. Give the milk a good shake before drinking.

The taste and appearance changes depend on the speed at which the milk is frozen. A slight change in taste, and/or some loss of color, is possible. These are very minor changes, and the milk remains a wholesome food. A good rule of thumb is: the faster the freeze, the smaller the damage.

I recommend that you put your well-sealed containers next to the freezer wall or on a metal shelf, where they’ll freeze quickly and remain solid for the duration of their storage. Remember, also, that because milk is a rich source of nutrients, it provides an ideal food for bacteria and other microorganisms. Pasteurization helps destroy most, but not all, of the bacteria present at bottling. Freezing doesn’t destroy microorganisms, it just suspends or slows their growth. Keep in mind that the quality of a defrosted milk, or of any other frozen food, will be no better than it was at the time it was frozen.

Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 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 am at a conference about food and cookware, and one chef was leading a discussion on the topic of eating meat. She said that most of the meat we eat is muscle -- for example, steak is cow muscle. During a subsequent conversation, I brought up this subject and another chef immediately disagreed, saying that we are eating the “fleshy part,” whatever that is. (There was no time for any follow-up questions or requests for clarity.) Would you be so kind as to elaborate a little? -- W.L., via email

DEAR W.L.: Steak and other “muscle meats” do come from the muscle tissue of an animal. “Flesh,” as it refers to meat, can mean soft tissue such as muscle, but also fat or organs such as the liver or kidneys. But keep in mind that “flesh,” as a generic term, can refer to animal tissues in general. Hope this helps.

DEAR DR. BLONZ: I was in a natural foods store looking for an alternative to regular coffee. I was told about “ganoderma,” which is made from an extract of ganoderma lucidum -- a concentration of six species of red mushroom. The plus side, as it was explained to me, is that it has excellent nutritional benefits and the flavor of coffee, but with a minimum of caffeine. I am having a difficult time finding much information on ganoderma. While this supplement was flavorful, I would like to know more about what I am ingesting. -- S.C., Milwaukee, Wisconsin

DEAR S.C.: Ganoderma lucidum is the Latin name for a species of reishi mushroom. This mushroom has long been used in Chinese medicine, and other natural medicine traditions, for enhancing the immune system. I have heard of the reishi being taken as a tea or dried as a dietary supplement, but have not tried it roasted as a coffee substitute.

Some thoughts: Mushrooms are complex organisms, and there are many different species. Some types have wonderful culinary uses, while others contain components that have medical effects. And there are a small number of mushrooms that contain powerful toxins. As is often the case with naturally occurring compounds, there can be variations from harvest to harvest. All this translates to a lot of unknowns about the precise identification and level of active ingredients.

Then there are the issues of changes that could take place during roasting. The product is being touted as providing benefits from the fresh mushroom, but is there evidence that the substances in the whole mushroom remain efficacious after roasting? If there are active ingredients, are there possible interactions with health conditions, medications or other dietary supplements?

Finally, if this is to become your regular breakfast beverage, are there issues with chronic usage? All this might come across as overly cautious, but it makes sense to have a cup of consideration when something new is being tossed into the mix. Coffee has had its popularity ups and downs (we are currently in an “up” phase), but its components are well-studied, and it’s been around for a while.

Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 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.