Food Sensitivities
You paid for a panel, it came back with eighteen foods highlighted, and you have been avoiding most of them since. You feel somewhat better, your diet has narrowed considerably, and you are not sure which of those two facts explains the other.
This is one of the most common situations women arrive with, and it is worth explaining carefully, because the test that produced that list does not measure what it is sold as measuring.
Three different things, routinely confused
Allergy. An IgE mediated immune response. Fast, reproducible, and potentially dangerous. Hives, swelling, breathing difficulty, anaphylaxis. This is tested properly and taken seriously.
Intolerance. Not immune at all. Lactose intolerance is the clearest example: the enzyme that breaks down lactose declines, the lactose ferments, and you get symptoms. Dose dependent, uncomfortable, not dangerous.
Celiac disease. An autoimmune condition triggered by gluten, with real intestinal damage and real long term consequences. Not a sensitivity, and it needs diagnosing properly.
What gets sold as a "food sensitivity test" usually addresses none of these three.
What an IgG panel actually tells you
IgG antibodies to a food are a normal record of exposure. Producing IgG to the foods you eat is what a healthy immune system does. It is, in a sense, a dietary diary written in blood.
Which is why these panels so reliably flag the foods you eat most. Eggs, wheat, dairy, yeast. Not because they are harming you, but because they are what is on the list of things you have eaten.
The major allergy and immunology bodies have repeatedly advised against using IgG testing to guide food elimination, and they are right to. The result is a long list, a narrowed diet, and no better understanding of what is going on.
There is a second problem, which is that narrowing the diet is not free. Restricting the range of plants you eat reduces microbiome diversity, which is one of the clearest things we know about gut health. The test can therefore make the situation worse in a way that is slow enough not to be obvious.
Before eliminating anything, have these considered
- Celiac disease must be tested while you are still eating gluten. Cutting gluten out first makes the test unreliable, and getting a diagnosis afterwards means months of deliberately eating it again.
- Any reaction involving swelling of the lips, tongue or throat, difficulty breathing, or widespread hives is an allergy question and needs urgent medical assessment, not a dietary experiment
- Blood in the stool, unexplained weight loss, or persistent vomiting
- Iron deficiency anemia with no obvious cause, which is a common first sign of celiac disease
How to find your actual triggers
The thing that works is slower and less satisfying than a printout, which is precisely why the printout sells.
- Keep a symptom and food record for two to three weeks first. Not to find the answer, but to see whether symptoms genuinely track food at all. Frequently they track sleep, stress or the time of the month more closely, and that is useful to know before you start removing things.
- Exclude the diagnosable causes. Celiac disease, and where relevant thyroid function and iron status. These are cheap, standard, and they change what you do.
- If food does seem to be involved, do a structured elimination. A short, defined period, a small number of foods, and a planned reintroduction. Reintroduction is the part that produces the information. Without it you have only removed things.
- Reintroduce one food at a time, properly. A reasonable quantity, over two or three days, with a few days before the next. Rushing this produces false conclusions in both directions.
- Consider whether it is the food or the fermentable carbohydrate. A great many apparent wheat and dairy reactions are FODMAP reactions, which behave differently and are dose dependent rather than absolute.
- Do it with support if the diet is already narrow. Elimination on top of restriction is how people end up eating twelve foods and feeling worse.
The honest summary
Food genuinely does affect how people feel, and dismissing that is as unhelpful as overselling it. The problem is not the idea that food matters. The problem is a test that converts normal immune activity into a list of prohibitions and charges for it.
The aim is the widest diet you can comfortably eat, not the narrowest one you can tolerate.
Back to gut health in midlife, or see the R.E.N.E.W. Foundation, which includes a structured reintroduction rather than an open ended elimination.
