DEAR READERS: There are many letters in the queue with questions involving homeopathy. Rather than responding to each, this column addresses homeopathy as a general topic.

Homeopathy is a system of medicine that came into prominence when medical practice included bloodletting and the use of leeches -- not its most shining hour. This new approach claimed an ability to stimulate the body's innate defenses and healing mechanisms, activating a vital force to help make the body well.

Traditional medicine sees symptoms as being caused by an underlying condition. Its medicines can have two separate types of effects: direct and reactive. The direct effect is what the drug is designed for. For example, the direct effect of an antibiotic would be to destroy a bacterial invader responsible for an infection. Reactive effects are also known as side effects or adverse reactions, because they are not desirable in most cases. A reactive effect of that same antibiotic might include nausea, abdominal pain or diarrhea.

Homeopathic medicines claim to be curative in nature, but to do so in a different way. Its medicines are formulated to encourage the body to heal itself. Such remedies do not have a direct effect of relieving symptoms, nor of addressing the underlying health problem responsible for them. Rather, homeopathic remedies are designed for their reactive effects: their purported ability to stimulate the body's healing powers. The body, stimulated in this way, heals itself, the theory goes -- and the symptoms are no longer present.

Key to homeopathic medication selection is the concept of "like cures like," also referred to as the "Law of Similars." According to this principle, an extremely dilute amount of a substance is used to treat symptoms that it would cause if taken at full strength.

For example, ipecac serum was once used to induce vomiting in cases of accidental ingestion of certain poisons. (Be aware that ipecac is no longer recommended: see b.link/4a4hbg.) Ipecacuanha is the name of the plant from which ipecac is derived. The active ingredients undergo 60x serial dilutions in a typical homeopathic preparation of ipecacuanha to treat nausea and vomiting.

Such homeopathic preparations are not recognized as effective by the Food and Drug Administration. Imagine the difficulty of investigating the effectiveness of homeopathic preparations in which the solution is so dilute that it is unlikely there's even one molecule of the original substance. This is one reason that evidence-based medicine remains skeptical about homeopathy: the lack of reproducible research that homeopathic preparations are effective for any clinical condition.

In 2016, the Federal Trade Commission began taking action against claims touting the efficacy of homeopathic drugs, holding them to the same standard as other products making the same claims -- a "prove it before you claim it" policy.

Although homeopathy medications may be safe, the theoretical danger is that someone with a treatable illness could bypass proven methods in favor of homeopathy, only to find that their ailment had grown in severity during homeopathic treatment.

Homeopathy has been around for about 200 years, but it remains theoretical, its underpinnings defying scientific logic. Consider that homeopathic products with totally different formulations can claim the same anti-disease effect. One thing they share is a lack of objective, placebo-controlled evidence supporting their efficacy. While different prescription drugs can be prescribed for the same problem, in such cases, evidence would have been submitted, and approval granted prior to the drugs' sale.

The bottom line is that homeopathy is based on a mysterious force scientists have yet to observe or quantify. Science is full of discoveries that transform the way we see the world, but until there is conclusive evidence to say otherwise, we are left to conclude that homeopathy and homeopathic medicines represent placebos.

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 read the ingredient lists on the products I buy, in addition to the Nutrition Facts labels, and stick to whole foods whenever possible. I would like some background information about natural color additives versus artificial ones. -- M.Q., Evanston, Illinois

DEAR M.Q.: The purpose of adding coloring is to make the item more appealing; when it comes to food, we are suckers for good looks. Would there be any consumer interest in gray hot dogs, brownish maraschino cherries or colorless colas, even if these are the actual colors of these processed foods?

Once, food coloring was used unscrupulously to hide the defects of spoiled merchandise. For example, small amounts of copper sulfate, now a known poison, were added to bring pickles to a brighter shade of green, and lead-containing dyes were formerly used to give candies their bright colors. It took the passage of the Federal Pure Food and Drug Act of 1906 to outlaw such practices.

Our brains have a hard time when food colors are wrong. One study demonstrated that volunteers couldn't correctly identify strawberry flavoring when it was tinted green. And in a classic test in the 1970s, people were fed a meal of steak, peas and French fries under lighting that concealed the foods' appearance. When the lights were raised to reveal blue steak, red peas and green French fries, several volunteers became ill despite assurances that the food was wholesome, just tinted.

Artificial colors have come and gone over the years. A notable case involved the 1976 ban of red dye No. 2, a widely used food and cosmetic coloring. Large amounts of the dye -- many times greater than would ever be used in food -- were found to cause cancer in laboratory animals. The ban focused public attention on artificial food dyes, and many companies shifted toward using natural colors.

While the name might suggest differently, natural colors are rarely natural to the foods to which they're added. Instead, they are color-rich chemicals from animal, vegetable or mineral sources. Natural red food coloring, for instance, can be extracted from beets or might come from carmine, a crimson pigment from the shell of a Central American insect. Both are considered "natural" red colors, and they're used in everything from fruit drinks to candy to strawberry ice cream.

Whenever colors are added, it must be indicated on the label, but the terminology for natural colors can be confusing. If a natural color is not "natural" to the food to which it's added, such as beet powder used to tint strawberry yogurt, the food cannot claim to be naturally colored. But since that beet coloring is natural, the yogurt could claim to have no artificial colors.

While there can be rare sensitivities to color additives, they are generally safe, given the small amounts used. There had been early reports about food colorings contributing to behavior issues in children, but these have not stood the test of further research and study. (Check the FDA page answering consumer questions at b.link/t2b2kg.)

It is always best to base our diets on whole foods that don't use color additives; such foods don't need help in the appearance department.

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: A recent letter asked about eating corn -- the writer, also from Tulsa, related a fear of eating corn stemming from some "doctor videos" they had seen. You replied that eating corn isn't a problem. I would like to share my experience.

In my teens, in the 1950s, I worked in the Iowa cornfields detasseling corn. Unknown to the average layperson, the fields were full of pesticides and herbicides, primarily DDT, dioxins and others. These chemicals persist in the soil for many years. We ate a lot of sweetcorn and popcorn.

Then in my 60s, I was diagnosed with non-Hodgkin lymphoma. The doctors stated that it is a known scientific fact that non-Hodgkin lymphoma is one of the cancers caused by pesticides and other chemicals used in farming. Consequently, I now only eat organic corn products, and try to stick to organic with other foods whenever possible. Perhaps wise advice for anyone. -- S.W. Tulsa, Oklahoma

DEAR S.W.: My regards for sharing your unfortunate experiences. We have learned much since the 1962 publication of "Silent Spring" by Rachel Carson helped identify and ban DDT and other pesticides. Public concern about pesticides typically focuses on potential dangers from eating the foods grown with their use -- but what about the workers who apply such chemicals? And what of our environment, which becomes the chemicals' final resting place?

America's obsession with perfect-looking produce is one of the key factors behind the continued demand for pesticides. In a report entitled "Alternative Agriculture" (available at b.link/9fz4gr), the National Academy of Sciences detailed how the food industry encourages the use of pesticides solely to maintain high cosmetic standards. Surveys about citrus fruits conducted by Public Voice and by the American Farm Bureau Federation found that, in some cases, over half of pesticides are used for cosmetic reasons, such as preventing minor external blemishes that have nothing to do with the taste or nutrition of the fruit.

Many health experts place the hazards from pesticides well behind other dangers in our food supply, such as bacterial contamination and naturally occurring toxins. They say that the major risks in our food supply are placed there by nature, not technology.

However, numerous unanswered questions remain. For example, there is no practical way of measuring how, or if, an amount of residue deemed safe today might affect your health down the road. We also have no way of judging the effects of residues in combination with each other, or what happens when pesticide exposure occurs in conjunction with other health problems or medications. That may be why, despite assurances, surveys reveal that American consumers continue to be wary.

There are alternatives to the continued use of pesticides. One, as you correctly point out, involves organic agriculture. Organically grown crops, which generally cost more to produce than most conventional foods, are raised without synthetic chemicals, such as pesticides, fertilizers, animal feed additives or growth regulators.

A reasonable bottom line: There's little question that it's better to eat conventionally grown produce than not to eat fruits and vegetables at all. Our produce market is not a hazardous place where we need to fear every bite. Yet this does not justify blind support for the use of unnecessary synthetic pesticides.

We should eat as though our life depends on it, and at the same time, we need to be aware of the environmental impact of our food choices.

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.