So much misinformation out there. And so many phony tests being pushed by the Internet.
I like this article, Common intolerance myths by Julie Deardorff of the Tribune Newspapers. I've cited her articles before and I'm happy to see that she's still on the job.
As always, I'm quoting selectively from the article for fair use. Please click on the link if you want to read the whole thing.
Claim: Food intolerances are caused by eating a repetitive diet; this overloads the immune system and the body responds by rejecting those foods.
Reality: "The gut-associated immune system is well-equipped to deal with loads of antigenic material, and there is just no evidence that it may become overloaded by exposure to large amounts of the same antigen," said Stefano Guandalini, founder and medical director of the University of Chicago Celiac Disease Center. Although the amount you eat never causes food intolerances, "if you are intolerant you will clearly have more symptoms if you eat more of that food," added Robert Wood, professor of pediatrics and chief of pediatric allergy and immunology at Johns Hopkins.
Claim: Hair sampling is a safe and noninvasive method of revealing nutritional deficiencies.
Reality: Hair is made up of a protein, keratin, that can be analyzed to determine its mineral content. That data can be used to find out if the body is lacking in certain minerals, but it can't tell you whether you have food intolerances, allergist Lee Freund wrote in "The Complete Idiot's Guide to Food Allergies." Double-blind studies haven't shown any diagnostic value for this test.
Claim: The IgG blood test is 95 percent reliable.
Reality: The test is prone to false positives and not considered reliable by any U.S. or European allergy or immunology society.