All foods both exhibit toxicity, and provide nutrients. I think the goal of nutrition is to choose the right foods in the right amounts to balance nutritional needs with toxic effects.
Unfortunately, this is easier said than done. When you really look into it we don't know much about human nutrition, but some choices are still better than others with the information we do have. The problem is I am having trouble finding a rigorous way to weigh these different choices. I guess the real question isn't "is gluten toxic?" but "are gluten containing foods more or less toxic than other alternatives which meet the same nutritional requirements?"
That's a great point about the lead cups, and smoking. It certainly makes me wonder what other things are hurting our health right now, that we potentially have the clues to identify but haven't managed to connect the dots yet.
"are gluten containing foods more or less toxic than other alternatives which meet the same nutritional requirements?
Nutritional and economic requirements. I'd guess gluten-free foods are no cheaper than otherwise-equivalent regular foods, so unless you're willing to spend an arbitrarily large amount of money on food that's also relevant.
Nutrition is a case where we have to try to make the best possible use of the data we have no matter how terrible, because we have to eat something now to sustain us while we plan and conduct more experiments.
I want to apply Bayes theorem to make rational health decisions from relatively weak data. I am generally wondering how one can synthesize historical human experiences with incomplete scientific data, in order to make risk-adverse and healthy decisions about human nutrition given limited research.
Example question/hypothesis: Does gluten cause health problems (ie exhibit chronic toxicity) in non-coeliac humans? Is there enough evidence to suggest that avoiding gluten might be a prudent risk-adverse decision for non-coeliacs?
We have some (mostly in vitro) scientific data suggesting that gluten may cause health problems in non-coeliac humans (such as these articles http://evolvify.com/the-case-against-gluten-medical-journal-references/). Let's say for the sake of arguing, that I can somehow convert these studies into a non-unity likelihood ratio for gluten toxicity in humans (although suggestions are welcome here too).
However, we also have prior information that a population of humans has been consuming gluten containing foods for at least 10,000 years, without any blatantly obvious toxic effects. Is there some way to convert this observation (and observations like this) into a prior probability distribution?