DEAR DR. BLONZ: I was looking up information on juicing “prescriptions” for arthritis and other maladies, but I found different information on different sites. These were mainly commercial sites, and many included customer testimonials. Is there anything consistent on the research side of this topic? -- J.F., New Rochelle, New York

DEAR J.F.: The lack of research to provide a scientific basis for “juice prescriptions” opens the door for an advice free-for-all. One site might endorse pineapple juice for arthritis; another pushes broccoli, kale and spinach; and yet another recommends celery, cherry, bean sprouts, carrots and cucumbers. While such foods all have nutritious attributes, prescribing them for specific ailments is a dubious proposition. (Testimonials are not objective evidence.)

Unfortunately, the focus on curing specific diseases overshadows the value of juicing. It’s a bit shocking that in 2018, soft drink consumption in the U.S. averaged about 38 gallons per person (see b.link/pce8f). Our bodies would be better off if we got our refreshment from water, or fresh vegetable or fruit juices, instead. Not only do juices have wonderful flavors, they also contain valuable nutrients not available in soft drinks. For example, a 6-ounce glass of fresh carrot juice contains only 73 calories and is loaded with healthful phytochemicals. Fresh apple, pineapple or melon juices yield flavors and aromas unmatched by any other beverage.

The beneficial effects of eating more fruits and vegetables are not disputed. And it’s a lot easier to drink a pound of carrots than to eat the same amount of vegetables. But because juice doesn’t have fiber and other solids, the goal should be to have juice in addition to, not instead of, fresh fruits and vegetables. And, although proponents of juicing might swear you get all the essential goodness (except the fiber), it’s unclear what proportion of the nutrients are left behind when the pulp is not included.

There are three basic types of juicers. Extractors, the most popular kind, grind the food with a high-speed spinning dish that traps the pulp. They often have an ejector that deposits the pulp in a convenient bin. Masticator-type juicers “chew up” the food at a slower speed and make juice by mechanically pressing the ground-up produce against a screen. Finally, there are specialized blender/juicers that grind the entire fruit or vegetable. This is the one type of machine that doesn’t remove the pulp, and as a result, juices from these machines retain the food’s fiber. The tradeoff, however, is that the output can end up as slush rather than juice.

Here are some tips for the juicer-to-be:

-- Taste a range of fresh juices before you spend money on a juicer. Find a juice bar in your area, or arrange for a demonstration so that you can sample a variety of freshly made juices. Make a note of the juicing method used.

-- When shopping for a juicer, find a model that’s easy to clean. If cleaning is a bother, the machine is likely to sit unused.

-- To avoid any possible digestive problems, don’t overdo it at first. Introduce new fruits and vegetables gradually.

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 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.