DEAR DR. BLONZ: You tend to go negative about products sold through network marketing. In my view, if a particular product has health benefits, these marketing programs allow people to join a company, help their friends and others, and make a profit at the same time. It is such a natural way to help and participate, and I am troubled by your typical rejections. -- S.T., Casa Grande, Arizona

DEAR S.T.: Any nutritional product sold should be able to support its claims with published research in real-world situations. I search for evidence that the directions for use and amounts provided are consistent with the claims being made. These claims are the ones that tend to attract prospective customers (and network marketers) in the first place.

Consider the regulatory context -- namely, that there is none. There is currently no regulatory requirement that dietary supplements demonstrate they are safe, or that they work as claimed, before they are marketed. If misconduct is suspected, the companies can be challenged by those charged with consumer protection, such as state attorneys general, the Federal Trade Commission or the Food and Drug Administration. But the up-front bill is paid by the taxpayer, as these challenges occur AFTER the product is already on the market.

I consider it a red flag when there is no objective evidence, but plentiful praise from those profiting from the sale. We must decide for ourselves, and mine is not an automatic condemnation. If you or a loved one has taken a product and it has appeared to have worked, it would be reasonable to consider joining the company and spreading the word. Ideally, a profitable business entity of this type would invest in independent (not in-house) research to test all their claimed effects. I encourage you to inquire if this has been done at the company you are considering. For more on network marketing, check tinyurl.com/q9dw95b.

DEAR DR. BLONZ: I have had a run-in with health issues, and I am attempting to make changes. I recently began taking a statin, but I confess to craving meat, eggs and cheese. With the pills, my cholesterol numbers have improved, but I am not confident that things are actually getting better. -- S.E., Hayward, California

DEAR S.E.: I have heard many express a “craving” for certain foods that had a central place in their diet. Many are successful at slowly transitioning from one style to another as they integrate a big-picture understanding of the connection between diet, activity, health and longevity. I am not talking about your physician telling you to cut back on meat or fat as an end in itself; I refer to gradually gaining an appreciation for how eating a healthful variety of foods contributes to health.

We are so over-specialized in this country. While there are exceptions, dietary changes usually don’t have to be all-or-nothing. What we have become good at is throwing a pill at a problem to make it go away. There is a definite interconnectedness that needs to be understood, and once you gain that essential bit of savvy, you will realize that you can eat the foods you love as long as your diet and lifestyle are in good shape. My advice is that you take the time to educate yourself. Read more about nutrition and health. Stick around, and I will attempt to push you a bit further along on that road.

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: Do carbonated beverages, such as soda water, interfere with the absorption of calcium or other vitamins and minerals? -- S.F., Berkeley, California

DEAR S.F.: Carbonated beverages are made by dissolving carbon dioxide gas in water under pressure. While these liquids tend to be slightly acidic, the body is designed to maintain the balance between acid and base (alkaline).

The key measure is pH: In chemistry, a pH of 7.0 is considered neutral; this is the pH of distilled water. The human body is slightly alkaline, and in good health, it will remain in a very narrow range -- between 7.35 and 7.45. Variations outside of this range can affect the chemical reactions essential for life. The master controller is our kidneys, the organs charged with removing/adjusting levels of substances in the blood while helping maintain ideal pH conditions within the body. The pH of our urine changes reflecting not only our state of health but also what we have recently consumed. Note that the body needs to be adequately hydrated for the kidneys to do their job.

Most foods measure on the acid side of the scale. Corn, for example, has a pH of 6.3; a carrot, 5.0; a typical salad-dressing vinegar, 3; cola soft drinks, about 2.4; and lemon juice, 2.3. The hydrochloric acid in our stomachs, used to break down foods, is a very strong acid with a pH of 1.0. On the alkaline (basic) side, baking soda and egg whites each have a pH of 8.0.

Regardless of its pH, soda’s (or any food’s) actual effect on the inner workings of the body depends on what gets done with the food’s chemical components. All things being equal, if you are adequately hydrated and eat anything that resembles a balanced diet, there is no need to be concerned about the effect that carbonated water might be having on the absorption of vitamins and minerals.

DEAR DR. BLONZ: The cereal my kids like says that it is made with whole grains, but when I checked the Nutrition Facts label, it says the dietary fiber is only 1 gram! What does “whole grain” on the label mean, nutritionally? -- S.P., Hayward, California

DEAR S.P.: A cereal product can be made with the whole grain or with parts of the grain. For food to state “made with whole grain,” the FDA requires that there be at least 8 grams of whole grain per labeled serving. If the product states “100 percent whole grain,” there cannot be any refined flour in the product.

Fiber tends to be in the fibrous outer coat (bran) portion of the grain, rather than the inside (flour) portion. Some grains have more fiber per unit weight than others. Also, some cereals use more of the non-fiber portion of the grain. Puffed cereals, for example, tend to use more of the flour portion than bran-based cereals.

The key comes from checking the entire ingredient list as well as the Nutrition Facts. I usually have cereal or granola with fresh fruit for breakfast and always look at this information before I buy. A good resource for information on whole grains and the various types of label terminology is the Whole Grains Council (wholegrainscouncil.org), an organization formed by the Oldways Preservation and Trust, a nonprofit food think tank.

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: 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.