Don’t waste your money on “food sensitivity” tests
© 2018 Roy Benaroch, MD
Ah Facebook. Where else could I stumble on a video of a baby hippo taking a bath, or Toto’s Africa performed on solo Harp? But among the shares and silliness and talent, there’s a dark side to Facebook. It’s become a fast way for quacks to push their scams and empty your wallet.
Just today in my feed I received a “promoted” post about a “Food Sensitivity Test”. I’m not going to link directly to the company – feel free to do a Google or Facebook Search, you can find them along with dozens of other companies that push a similar product. What they’re selling, they claim, is an easy, at-home test that will reveal your “food sensitivities”. They say their test won’t diagnose allergies (which is absolutely true), but it will help you find out which foods might be causing things like “dry and itchy skin, other miscellaneous skin problems, food intolerance, feeling bloated after eating, fatigue, joint pain, migraines, headaches, gastrointestinal (GI) distress, and stomach pain.”
This is absolute nonsense. Their test can’t in any way determine if any of these symptoms are possibly related to food. What they’re testing for in your blood, they say, are IgG antibodies that react to each of 96 different foods in your body. But we know that these IgG antibodies are normal – all of us have some or most of these if we’ve ever eaten the food. IgG antibodies are a measure of exposure, not a measure of something that makes you sick or makes you feel ill. Having a positive IgG blood test for a food means that at some point you ate the food. That’s it. Nothing more.
This isn’t something that we just now discovered. IgG antibodies to food have been a known thing for many years. We know why they’re there and we know what they do. And we know testing them is in no way indicative of whether those foods are making you sick. Recommendations from the American Academy of Allergy Asthma & Immunology, The Asthma and Allergy Foundation of America, the American College of Allergy, Asthma, and Immunology, and the European Academy of Allergy and Clinical Immunology all unequivocally recommend against food IgG testing as a way to evaluate possible food sensitivities. The testing just doesn’t work to reveal if a food is making you sick.
But that doesn’t stop quacks from direct-marketing on Facebook. If you’re offered IgG-based food sensitivity testing, either through the mail, at a physician’s, or at a chiropractor or naturopath, I’ll tell you exactly what it means: Save your money and run the other way. Whoever is pushing the test is either deliberately deceiving you or doesn’t understand basic, medical-school level immunology. It’s a scam.
More details about the (lack of) science behind IgG food testing
Tags: allergy, diet, immunology
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The Pediatric Insider 
September 20, 2018 at 8:56 pm
There are two kinds of primary reaction to a food that one has an allergy to, full blown anaphylaxis on a sliding scale of severity (my wife is moderately sensitive to shellfish proteins, our youngest is nearing a full blown level of sensitivity due to repeated exposures to proteins in the air while things like shrimp is being cooked, as she’s a professional chef and autoimmune reactions, as was mentioned in the fine article you linked to.
Indeed, I’ve had a full blown anaphylaxis episode, complete with shock, from only two doses of amitriptyline.
There is another sensitivity, where the lack of an enzyme could actually kill someone. I know that you’re aware of it, but many a reader wouldn’t likely be, save if they’ve known of someone with the deficiencies in question, so I mention it to add some knowledge.
An example that is moderately common is G6PD, I’ll avoid the full name, as Google can retrieve it for an interested reader, but the common name is favism. Exposure to fava beans (also known of as broad bean), certain relatively common drugs and even lighter fluid can cause severe hemolytic anemia. The red blood cells literally rupture, en masse. OK, not quite all at once, it depends upon the severity of sensitivity, amount of exposure and a few other factors. But, it’s a case where food can kill.
Oddly, one area where fava bean consumption is significant is also known to have a significant number of the population that cannot enjoy those tasty beans (personally, I love them in my falafel (that family recipe uses chickpeas and fava beans)). Considering my ethnicity (Sicilian-American), it’s a pleasant surprise that I am not deficient in that important enzyme. Considering the common drugs that could have caused a problem and my liking for that bean, I’m quite fortunate!
For those interested, hopefully this link will survive to the Wikipedia article, which is quite good (B class article, for fellow Wikipedians).
https://en.wikipedia.org/wiki/Glucose-6-phosphate_dehydrogenase_deficiency
That certainly contrasts against what the woo peddlers are trying to sell as a “food sensitivity”!
Real allergies range from my hay fever when someone mows grass near me, nose runs like a faucet, causing a cough, which if I don’t get inside quickly, leads to projectile vomiting (pretty much the only form of vomiting I do, due to a non-functional esophageal sphincter, which gives me severe GERD) if I don’t get a drink of water to get peristalsis going back in sync after the insult of pressures induced by the coughing. OK, maybe it’s barely functioning, I only know that tooth erosion has been severe enough for significant tooth loss. Certain black molds will leave me running outside, to bend over and let it flow out, rather than where it could drown me or cause my stomach to object. Yeah, bad scene.
Allergy season/heating season still on, brings epistaxis (aka nosebleeds) that can leave the room that has a drain (bathroom or kitchen) looking like a murder scene, losing at least a pint of blood in one episode. People like me made the Red Cross change their tilt the head back directions many years ago, as that causes the blood to go straight down the throat, to threaten drowning in one’s own blood.
Fortunately, I’m rather good at clotting, if left to my own devices, I bleed out into a sink or toilet, then have to wash a mess out of said receptacle, then the floor and possibly the walls. Give it a half hour post clotting, I can blow the clot from my sinus.
I’m sure someone’s selling woo to “prevent” that as well, maybe vitamin C overdoses, to send the unsuspecting G6PD patient into the ICU… 😉
Do read the Wikipedia article if you failed to understand that really, horrific joke. True, but horrific.
To more fully understand the horror, you’d need to know the behavior of CO2 in the presence of water under even fairly modest pressure, carbonic acid, well, turning blood into weak soda pop and the bad things that acid and toxin does, adding in CO2 as a toxin and well, a lot more. Red blood cells are critical in that entire life thing for humans and well, most vertebrates.
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