DEAR DR. BLONZ: I have a severe reaction to shellfish like crab and lobster, but eating shrimp doesn't bother me at all. My question relates to scallops: I want to be able to eat them, but am unsure if I can do so safely. The nutritionist I consult with said that my allergy was probably due to iodine, but I am not sure how this could be the case. -- S.I., San Jose, Calif.
DEAR S.I.: While some people may react to iodine, that is usually only when it's applied in large amounts as a disinfectant, as in surgery or other medical procedures. The typical shellfish allergy is not due to the presence of iodine. Iodine is an essential mineral needed by the body to make the thyroid hormone. It is found in most seafood, and is also present in foods made with iodized salt, which includes many restaurant foods.
When there is insufficient iodine, the thyroid gland, which is located in the throat, becomes enlarged and the condition referred to as "goiter" results. Goiter used to be common in the Great Lakes regions of the United States, but the condition was virtually eliminated following the addition of iodine to table salt in 1924.
Rather than iodine, allergies to shellfish -- including clams, crabs, lobster, oysters, shrimp and scallops -- tend to be caused by a protein found in the shellfish. It is unusual that you would tolerate shrimp when crab and lobster set you off. Because scallops are in that shellfish group, I suggest you refrain from any experimentation -- especially because you classify your reaction as "severe." What you need to do is to speak with your physician -- not a nutritionist -- and undergo a standard allergy test conducted by an allergist. In these tests, you will be exposed to very diluted extracts of shellfish, along with other substances that may be suspect. The test is done in a safe, controlled setting.
DEAR DR. BLONZ: I have been advised to seek a holistic medical doctor who uses a technique called "muscle testing" to determine which nutritional supplements I should be taking. In this type of testing, the doctor places supplements under my tongue. Then, while I am on my back, he has me raise my right leg about 10 inches. If he can press my leg down, he recommends that the supplement be taken. If he cannot force my leg back down on the table, he says I don't need the supplement. What is your opinion of this technique? -- B.R., Coolidge, Ariz.
DEAR B.R.: My opinion is that this test is questionable to say the least. I have never found any evidence to support the reliability of such a technique. I would approach with caution any other advice from the individual who told you to seek such stuff.
Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to email@example.com. Due to the volume of mail, personal replies cannot be provided.