What is IgG testing and is it a good tool for use with digestive disorder patients? On Instagram @AndreaHardyRD, I talk all about how important it is to critically review the evidence on IgG testing before considering it’s uses in patients with digestive disorder.

Image of @andreahardyrd Instagram post about IgG testing for digestive issues

Good research STARTS with a hypothesis, or question.⁠

BAD research starts with the outcome you want, and builds it’s study around trying to prove that outcome.⁠

IgG test kits & research are unequivocally bad, in my opinion. ⁠

They’ve: ⁠
✖️developed and monetized a technology based on a theory⁠
✖️sold it as a health promoting tool⁠
✖️got called out on their bullshit⁠
✖️and now has to back track to design studies to ‘prove’ its utility⁠


There are better ways I can think of to spend $500 on your health. ⁠

???? IgG is an immune marker in your body. Everyone assumes you don’t want your immune system to ‘react’. Realty is, a functioning immune system requires the perfect balance of recognition and reaction.⁠

????Allergies & sensitivities occur when you have something called a ‘loss of tolerance’ – meaning your immune system no longer recognizes that food antigen as safe.⁠

????IgG antibodies play a CRUCIAL role in recognizing recognizing that food antigen – ‘immune tolerance’⁠

???? so the measurement of IgG antibodies is a marker of immune tolerance and recognition, NOT a sensitivity ⁠

????the foods that will most often test highest are the ones we consume the most. This often validates the test in our minds ⁠
“of COURSE this makes sense, these are foods I eat all the time, no WONDER I’m sick” – is what I hear. ⁠

????In the 1 RCT on IgG & IBS (NOTE: not a great design, missed the mark in the discussion), a large portion of control patients responded to the sham diet. The placebo effect of dietary elimination, especially when you’ve paid a lot of money, is significant. Not to mention, when put on a restrictive diet, there’s often more whole foods, more eating at home, and better diet quality. ⁠

????I have yet to see an IgG test result that doesn’t eliminate wheat, milk, or legumes of some sort. Many foods eliminated are high FODMAP foods. Do we need to take a sledge hammer (and an extra $500) to kill a mosquito? probbbbbably not – we have a more tailored, less restrictive approach to manage IBS, that doesn’t require any expensive testing, called the low FODMAP diet! ⁠

So. Save your money folks. Skip IgG testing. ⁠⠀⁠