DEAR DR. BLONZ: Is it possible that consuming local honey can help build an immunity to local allergens? -- S.T., Berkeley, California

DEAR S.T.: Honey can contain trace amounts of proteins from the flowers serviced by the bees, but there is little data that consuming this honey can prevent, or even lessen, allergic reactions to those flowers.

If it worked, eating honey would be a convenient way to get desensitized to local allergens, and desensitization therapy -- also called immunotherapy -- is considered to be a good preventative treatment for some allergies. Unfortunately, there is no evidence that the body's immune system, the one responsible for most allergic reactions, can respond to honey in that way.

Traditional immunotherapy usually involves injecting an allergen into the skin of the arm. The process is carefully orchestrated, starting out with minute amounts -- below the threshold of sensitivity -- and then gradually increasing the exposure until it's up to a level likely to be encountered in real life. It can take weeks or months to complete the regimen, and even then, there is no guarantee.

Local honey is likely to contain a "wild card" of allergens of unknown concentration. There would also be seasonal variations, making it difficult to project which allergens would be present, and in what amounts.

Absent the tenets of folklore, there is little objective evidence that eating local honey helps desensitize one to local allergens. It is a concept, however, that has its adherents. The practice is unreliable at best, and certainly not recommended for those with severe allergies.

One final note: Honey of any kind is not recommended for infants under 1 year of age. Honey can contain small amounts of botulism spores from dirt or dust, picked up by honeybees. This small amount isn't a hazard to older children or adults, but it does present a risk to an infant's immature immune system.

DEAR DR. BLONZ: You recently talked about vitamin names, and I was wondering: Is there a vitamin O? I suffer from migraines, and I have been reading literature that explains how this vitamin can help me. I believe that the "O" stands for the substance's oxygen-releasing ability. The vitamin is sold in a liquid form. The product is expensive, so I don't want to buy it if it isn't going to work. -- W.R., Madison, Wisconsin

DEAR W.R.: Vitamin "zero" would be a more appropriate name, because that's the number of studies I could find affirming its existence, or its theoretical effects. I did find a number of websites selling this stuff, which is strange when you consider there is no such compound. The Federal Trade Commission penalized a company in 2000 for making false health claims for "vitamin O" (tinyurl.com/q9k8cvr).

It's always best to investigate miraculous-sounding compounds, as you did, before you send in your money.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 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: Calcium citrate and calcium carbonate are sold as supplements to build strong bones and prevent osteoporosis. I would appreciate your help in understanding the advantages or disadvantages of these and other types of calcium supplements. Are they equal in benefits? -- P.S., San Diego

DEAR P.S.: I receive many questions about calcium supplements, and as you point out, there are no shortage of options. The key is to get the calcium from the digestive tract into the rest of the body; that means that the calcium will have to be in solution so that it can pass through the absorptive surface of the intestines. A pill should dissolve in the stomach within 30 minutes if uncoated, or 45 minutes if coated.

Once the calcium compound breaks down, the next step is for it to meet up with the body's vitamin D-dependent calcium binding protein. This protein attaches itself to calcium and escorts it through the intestinal wall. As is obvious by its name, vitamin D is needed to stimulate the production of this binding protein. Although D does not need to be in the stomach at the same time as the calcium, the body has to be adequately nourished with vitamin D for the process to work effectively. The recommended dietary allowance (RDA) for vitamin D is 600 IUs (International Units) per day for those aged 1 to 70, and 800 IUs per day for those over 70. (The body can make its own vitamin D when it's exposed to sunlight, but for those who use sunscreens -- hopefully all of us! -- consuming foods that contain, or are fortified with, vitamin D is important.)

There are many different calcium compounds, each with varying amounts of elemental calcium per unit weight. Be sure to look at the Nutrition Facts or Supplement Facts label on any product, as this will list the actual amount of calcium per serving. The RDA for calcium is 1,000 milligrams per day for those aged 19-50 years of age. Recommended levels for other age groups can be found at: tinyurl.com/nrem7yj.

The calcium in dairy products is readily absorbed; here are some typical calcium-containing compounds found in supplements:

Calcium carbonate: poorest absorption; most calcium per pill (40 percent by weight), which means fewer pills to take; least expensive; most common form of calcium found in supplements; found in antacids. Can cause gastric acid rebound if taken on an empty stomach.

Calcium gluconate and calcium lactate: better absorption, less calcium per pill (9 percent and 13 percent respectively), so more pills needed to get an effective dose; more expensive; less commonly found in supplements.

Calcium citrate and calcium citrate-malate: best absorption; less elemental calcium per pill than carbonate (calcium citrate is 21 percent calcium by weight), so more pills needed; more expensive; gentler to the stomach.

The choice is yours, as any one of these can work as a calcium supplement. It is generally agreed that it is best to take calcium supplements at mealtime.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 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 always wondered about the letters and numbers used to identify vitamins. Why do they skip some letters, and why are there so many different B's? -- S.Y., San Jose, California

DEAR S.Y.: The word "vitamin" was coined in 1912 by Polish scientist Casimir Funk, who was searching for a cure for beriberi -- a paralyzing disease that was common in regions where white rice was the main dietary staple.

Contemporary research had suggested that the rice husk and bran might contain a substance that could combat the dreaded disease. Funk identified the key compound -- now called thiamin -- and dubbed it a "vital amine." This term was eventually shortened to "vitamin," and came to signify an entire class of essential compounds that are needed by the body in trace amounts.

All vitamins can be found in food. They do not provide energy (calories) and they are all "organic," in that they are constructed using the element of carbon. They perform specific metabolic functions in the cell, our basic unit of life, and they cannot be made by the body in amounts sufficient to meet its needs.

The absence of a vitamin from the diet can lead to a failure to thrive and the development of a deficiency disease, though the length of time it takes for problems to develop differs with each vitamin. It is interesting to note that not all animals require the same vitamins. Humans, for example, cannot manufacture their own vitamin C (ascorbic acid), which many animals can; this explains why our dogs and cats don't need this vitamin like we do.

Back in 1913, scientists came up with a naming system that was based on two groupings: those that would dissolve in fat were called "fat-soluble A" vitamins, and those that would dissolve in water were referred to as "water-soluble B" vitamins. The naming then proceeded in order of discovery. Many times, a substance thought to be a vitamin was later determined not to be essential. When this happened, that letter ceased being used.

In some cases, the first letter of the compound's function was used in its name. For example, vitamin K comes from the German "koagulation" (coagulation), or the clotting of blood -- a process in which vitamin K plays a role.

The "B" vitamin, originally found in yeast, was originally thought to be only one compound. When it was later found that there were many different compounds, they were given the names vitamin B1, B2 and so forth. This is now referred to as the vitamin B complex.

At present, there is no universally accepted naming system, and letters have apparently lost some of their appeal. Some compounds are called by their chemical name, as opposed to a letter/number designation. Examples include biotin (vitamin B7) and folic acid/folate (vitamin B9).

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 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.