I've talked about IgG testing previously, but in case you need a refresher, an IgG test is a blood test that proposes to improve your health by identifing food "intolerances" (not necessarily allergies). I'll leave the rest of the primer to Scott Gavura, a Canadian pharmacist who writes for both Skeptic North and Science Based Medicine:
IgG blood tests like Hemocode and YorkTest are clinically useless for diagnosing food intolerances, yet pharmacies imply otherwise. These tests claim to identify sensitivity to hundreds of products – yet not one has been validated. That’s because there no proven correlation between positive results on an IgG blood test and a true food intolerance. Not only are these tests use to shape dietary modification, they’re also used to sell supplements – another unproven use of IgG testing. Yet despite recent cautions against this testing, it continues to be offered.
A host of professional organisations including the American Academy of Allergy, Asthma and Immunology, the Australasian Society of Clinical Immunology and Allergy, the British Dietetic Association, and many more have all recommended that consumers avoid using these tests to diagnose allergies or intolerances, because the evidence just isn't there.
In response to my previous post about Dr. Elaine Chin's scientifically bankrupt endorsement of IgG testing, a reader going by the pseudonym "Still Searching" had this to say:
Many people suffer from chronic conditions that traditional medical practitioners have been unable to alleviate. [Although] the relationship between chronic health conditions and IgG response and use of IgG test results may not be proven, there is a significant amount of anecdotal evidence of dramatic improvements in health through use of elimination diets and similar. Should we wait decades for medical proof before investing $200 in a simple test that might lead to a change in diet that might significantly reduce chronic depression? Pharmaceutical companies will gladly invest the millions of dollars to fund scientific studies because they stand to make 100′s of millions of dollars in profits from successfully patented drugs. Who is going to fund expensive scientific studies that result in reduced drug use and changes in diet? Such studies will come slowly. Meantime, I think this is a small investment, with much better odds than, say, continuing to seek advice from doctors who have been unable to help for years. It’s important to know this testing is unproven, but we all need to inform ourselves before choosing any course of treatment, and make our own informed choices.
While I'm sympathetic to some of the sentiments that this person has expressed (and I certainly appreciate the courteous and thoughtful manner in which it was done—it's a rarity hereabouts), I do not share the commenter's apparent optimism that the results of IgG tests are at all useful in determining intolerance to foods, for reasons that I think are quite clear by now.
Should we wait decades for medical proof before investing $200 in a simple test that might lead to a change in diet that might significantly reduce chronic depression?
The $200 is a reference to the fact that another commenter mentioned that he or she wasted that much money on an IgG test that proved worthless. For many people, $200 is rather a lot to pay, but potentially worse is the fact that any given IgG test is sure to prompt the customer to eliminate certain foods from their diet, probably unnecessarily, which is a major inconvenience at the very least.
And a change in diet might significantly reduce chronic depression? Well, whether it's worth the $200 depends on how likely it is that you'd see an improvement. And for that, we want to see clinical data. If you disagree, I have a rock for sale that may interest you: it might prevent tiger attacks.
Pharmaceutical companies will gladly invest the millions of dollars to fund scientific studies because they stand to make 100's of millions of dollars in profits from successfully patented drugs. Who is going to fund expensive scientific studies that result in reduced drug use and changes in diet? Such studies will come slowly.
They're certainly not going to bother funding such studies when they realise that they can just sell the service to people whether it works or not. That's why so many companies that sell nutritional supplements are owned by major pharmaceutical corporations: because of the way the these products are regulated (hint: very, very poorly), they don't have to invest the research dollars before they turn a profit. (Alacer Corporation, the manufacturer of "Emergen-C", is owned by Pfizer for example.) Which brings up another point: While patented drugs are great for the bottom line, you can still turn a tidy profit on something that is not patentable (or whose patent has expired). Vitamins and supplements aside, Aspirin still makes quite a lot of money for Bayer, despite the fact that Bayer's patent on acetylsalicylic acid expired 96 years ago.
I find it troubling that while this commenter is quick to point out the profit motive of major pharmaceutical companies, he or she seems to ignore the fact that the companies who provide these testing services are making boatloads of cash from selling these tests, all without bothering to do all of that pesky science to make sure they actually work.
Because the relationship between chronic health conditions and IgG response and use of IgG test results may not be proven, there is a significant amount of anecdotal evidence of dramatic improvements in health through use of elimination diets and similar.
I'm curious as to why this person is so quick to dismiss the many professional associations in relevant medical and nutritional fields (those qualified to assess the state of the evidence) that have determined that IgG tests are worthless. More details are provided by Scott Gavura over at Science Based Medicine.
As for there being "significant anecdotal evidence" for the efficacy of IgG tests, I'll simply point out that there also seems to be "significant anecdotal evidence" against the efficacy of IgG tests. (Not to mention actual, non-anecdotal evidence to that effect.) While anecdotes are certainly useful in pointing research in new and potentially fruitful directions, they are not in and of themselves especially useful in determining efficacy.
When you get right down to it, this is an argument about health freedom and informed consent, but everyone isn't going to be well-informed on every topic all the time. For this reason, I'm of the opinion that health products should be subjected to robust regulation, with emphasis placed on both safety and efficacy (and without dubious exemptions for products marketed as "natural"). There will always be Kevin Trudeaus* and Leonard Coldwells trying to sell nonsense disguised as medicine, and we should be trying to make it as difficult as possible for them to do it.
It's important to know this testing is unproven, but we all need to inform ourselves before choosing any course of treatment, and make our own informed choices.
I could not agree more.
* Or would the proper plural of "Kevin Trudeau" be "Kevin Trudeaux"? Perhaps "Kevins Trudeau"?