DEAR DR. BLONZ: There are always discussions this time of year about the annoyance of mosquitoes and how I seem to be their favorite target. A while ago, I was advised to take 100 milligrams of vitamin B1 twice a day to help repel the critters, and it seems to have worked. I received similar positive feedback at the time from others when they tried it. But I am now concerned about whether this is something I could recommend for my 10-year-old granddaughter, who is about to head to overnight camp. -- S.F., Anderson, South Carolina
Advertisement
DEAR S.F.: Some people seem more attractive to mosquitoes than others. To make oneself uninviting to mosquitoes would be an asset, no doubt. There are anecdotal reports that some people achieved benefits from taking vitamin B1 (thiamine); however, these are casual reports and not the result of any rigorous, objective data collection. To achieve any level of reliability, studies examining the efficacy of a mosquito repellant should compare the treatment with an inactive placebo in a blind study.
Thiamine had its moment, but objective, double-blind studies failed to affirm that it works to prevent mosquito bites with any reliability. You asked whether to recommend thiamine for your granddaughter at camp. The RDA (recommended dietary allowance) for a 10-year-old is 0.9 mg per day, so the 100 mg twice-a-day regimen you mention represents a megadose -- 222 times her recommended level. So the answer to your query is "Nope, not recommended." I'm glad you asked.
Unfortunately, no dietary supplement has proven effective at repelling mosquitoes. Mosquitoes and other biting insects are attracted to perfumes, food and brightly colored clothing. Eliminating stagnant water -- which is a mosquito breeding ground -- from around your house and yard can help. (For more information on how to choose an insect repellant, check out b.link/vtpbxnf. If possible, get a sample before purchasing a repellant, as some people find certain scents to be disagreeable.)
DEAR DR. BLONZ: I have read articles that say combining calcium with vitamin C at the same meal is not good, as one counteracts the other. This notion creates a problem for me at breakfast. I like to enjoy my fresh-squeezed orange juice with a serving of yogurt or cottage cheese. If these nutrients are incompatible, why are some orange juices fortified with calcium? I appreciate your answer. -- D.W., Scottsdale, Arizona
DEAR D.W.: No incompatibility here; these nutrients go well together. If anything, the vitamin C helps keep the calcium in solution and facilitate its absorption.
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.