DEAR DR. BLONZ: I am concerned about my magnesium intake, and I have read that it’s a nutrient that many fail to get enough of in their diet. One site extols the virtues of taking 400 to 600 milligrams of magnesium glycinate or magnesium citrate every day. I have seen magnesium supplements, but none that mention glycinate or citrate. Is there anything special about these forms? What is your opinion of such supplements? -- S.F., New York City

DEAR S.F.: Nothing special; assuming it gets dissolved, it’s the magnesium that is key. And the way magnesium gets compounded affects the ease with which it dissolves. “Glycinate” signifies that the mineral -- in this case, magnesium -- is combined with the nonessential amino acid glycine. “Citrate” indicates that magnesium is a salt made from citric acid (citrate).

Getting the mineral into solution is essential. After taking a supplement, the churning action of the digestive system helps the magnesium ions come into contact with the absorptive surfaces of the intestines, which, of course, is the goal. Taking a magnesium compound with a meal can provide liquid and an acid environment to help this happen.

Magnesium is an essential element needed for healthy bones -- in fact, half of the body’s magnesium is in our bones -- but also for nerve transmission, muscle relaxation and normal heart rhythm. The Daily Value for magnesium is 400 milligrams a day. Good dietary sources include avocado, nuts, bananas, legumes, whole grains, dark leafy greens, milk and oysters.

A plant-based, whole-foods diet is the priority. As a supplement, magnesium comes in a number of forms, including gluconate, aspartate, chloride, carbonate, hydroxide, lactate, orotate, sulfate and, as you report, glycinate and citrate. There are health conditions and medications that can affect the body’s ability to absorb magnesium, so check with your health professional or pharmacist to see if there might be an issue for you.

A couple of articles for follow-up: First, one from the National Institutes of Health that includes a discussion of groups at higher risk for magnesium deficiency: shorturl.at/mC358. Next, check out this ConsumerLab article about dietary supplement pills and how they dissolve: b.link/7bhpk.

DEAR DR. BLONZ: I have read that drinking a combination of one teaspoon of vinegar and one teaspoon of honey in a glass of water helps promote fat-binding so that fat is passed out of the body as waste. Any truth to this? -- W.W., via email

DEAR W.W.: Nope. The “fat-binding” and “passing out of the body as waste” is unsupported nonsense. There is nothing dangerous or wrong with this regimen, but the only way that a mixture of vinegar and 20 calories’ worth of honey could promote weight loss would be if you had that in place of higher-calorie foods.

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: Hyperactivity and behavioral issues in children are often thought -- by parents, staff and some health professionals -- to be associated with certain foods. However, there has been no clear clinical evidence that food causes behavioral issues in children. I work with children as a registered dietitian in a psychiatric facility, and am interested in your comments. -- S.F., Phoenix

DEAR S.F.: You have my respect and admiration for your work in this important area. There is no question that food allergies exist, but attributing food allergies with childhood behavior issues remains controversial. That said, it is not unreasonable to at least consider foods as a possibility if other avenues have been unproductive.

It is essential to proceed cautiously, reviewing patient history and calling upon a clinician experienced in this area. Consider that connections between behaviors and offending substances do not always display in a manner that makes it easy to connect the dots. You want to avoid placing the blame on the wrong substances without evidence. Jumping to conclusions can change parental behavior, which then gets learned by -- or should I say foisted upon -- their child in the form of statements like, “You shouldn’t eat that; it will make you sick.” All this can become a march down an unproductive path with ever-growing limits placed on the child’s ability to eat and enjoy their life.

The ironic thing is that a parent might observe improvements in their child’s behavior even if the wrong substance is identified. It might be a case of the child “growing out” of the problem during the “treatment period,” and the dietary switch getting the credit. Improvements can also take place because they are expected; this is the essence of the placebo effect. If the underlying problem was not food-allergy-related, though, it could remain. If the symptoms resurface at a later date, other foods or food categories might get added to the “banned” list, further restricting the child and the parents.

This is only a scenario, but I bring it up because it highlights the importance of an accurate diagnosis. The parents can assist the process by maintaining a log of foods consumed and reactions observed, and this can aid a trained health professional in compiling the likely foods for further testing.

Once nutritional “suspects” are identified, testing in a controlled clinical environment is essential to remove any possible bias from all concerned parties. The gold standard is the double-blind, placebo-controlled food challenge.

Keep in mind that 60% to 80% of children with allergies to milk or egg outgrow them by age 16, which suggests a need for repeat allergy testing as a child ages. I would encourage you to discuss this with your patients’ parents and the physicians on staff.

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: We are doing a project on nutrition labeling at school. I have noticed that fruits or foods (such as tuna) can be packed with a liquid that contains calories from sugar or oil. Does the listing of calories per serving include the calories from the liquid? If I drained most of the juice or oil off the food before eating it, approximately how many calories (or fat grams if appropriate) would be saved? Here's the info from a single-serving can of peaches: serving size 1 cup; calories: 120; total fat: 0 grams; sodium: 15 milligrams; potassium: 150 milligrams; total carbohydrates: 29 grams; fiber: 2 grams; sugars: 27 grams. Here is the ingredient list: peach slices, water, sugar, natural flavor, citric acid and ascorbic acid. -- B.T., Tulsa, Oklahoma

Dear B.T.: The Nutrition Facts panel describes the portion upon which the numbers are based. There may be brand-to-brand differences. If there is no statement that the nutrition information is based on drained contents, it should be assumed that the serving is a portion of the entire contents. In the example you provide, it would be the entire contents of the can, including the juice.

There is, of course, the option of draining the liquid to avoid some of the sugar calories. You can also decrease sugar and carbohydrate calories by using fresh fruits or fruits packed in water, rather than heavy syrup, or doing a fresh-water rinse of fruits packed with the syrup. With tuna, a similar goal would be achieved by draining the oil, but there will always be some oil left. (Be aware that the oil used in canned tuna is usually vegetable oil, not the omega-3-rich oil found in tuna.) You can select a brand of tuna that is packed in water.

Although not in the case you cite, products often list the nutritional value of the drained contents. For your project, consider creating a table that lists the nutrition facts between similar serving sizes of drained fruit from different liquids. By comparing the same portion from brands packed in light syrup, juice and heavy syrup, and comparing these with one packed in water, you can see the number and type of calories the accompanying liquid leaves behind after draining. For tuna, you can do this with the drained oil-pack vs. water-pack cans.

Dear Dr. Blonz: I read an article written by a respected scientist who said that that dairy foods and beef contain trans fatty acids naturally. I had thought that they were the result of hydrogenation or high processing temperatures. -- W.P., Sun City, Arizona

Dear WP: Small amounts of trans fatty acids can be formed by the bacteria that normally live in the rumen of the digestive system of cattle. (The rumen is the part of the bovine digestive system that helps break down the grasses, shrubs and grains consumed by the cow.) These are different from the ones formed during the commercial process of partial hydrogenation of vegetable oils. There is no evidence that the naturally formed trans fats represent a health risk, especially given the small amount present.

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.