How to use human history as a nutritional prior?

It also took a while to notice the effects of cigarette smoking.

While tobacco was used by Europeans in some quantity since the early colonization of North America, it was the mass-production of cigarettes in the late 19th century that made heavy smoking a possibility for a large number of people. The first medical work showing a link between smoking and cancer came out in 1912 and 1929.

But smoking didn't get really huge in the U.S. until the mid-20th century, the era of mass media marketing of cigarettes (L.S./M.F.T.!); the British Doctors Study in 1956 was statistically pretty darned conclusive from a Bayesian standpoint, but was famously opposed by R. A. Fisher. Much of the later controversy on the subject of tobacco and cancer was manufactured by the tobacco industry, well after the matter was scientifically settled.

Sources:
http://en.wikipedia.org/wiki/Health_effects_of_tobacco_smoking
http://www.cdc.gov/tobacco/data_statistics/tables/economics/consumption/
http://en.wikipedia.org/wiki/British_Doctors_Study

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.

Yes, it exists: http://genomera.com

They're actively running experiments and collecting data but are in "beta testing" and are very exclusive on whom they allow to join. I'm disappointed they didn't choose me when I filled out their request for a beta invite.

A huge problem with collecting data like this in the US population, is that everyone has a similar diet. There's so few people totally excluding gluten, you can't expect to measure it's effects with epidemiological diet surveys: you need to actually do a controlled trial where you tell people to avoid it.

In China where only about half of people eat foods with gluten the biggest epidemiological study ever performed (the China Study) did find that wheat intake was independently correlated with overall mortality (http://rawfoodsos.com/the-china-study/). They never published this finding themselves, but the correlation is clearly there in the data.

There's a lot of question about their methodology- they didn't keep or report data on individuals, but lumped whole communities together as single data points. There's likely a lot of highly correlated regional habits that weren't on the questionnaire, and I tend to find the whole study pretty questionable. For the most part, it's just comparing the health of rural farmers with wealthier urban Chinese- the two groups have radically different health, lifestyle, and diets and we can only control for the few questions they actually asked.

Perhaps now that gluten avoidance seems to be becoming a "fad diet" in western countries, suddenly it will be possible to actually collect good data on this.

The folk wisdom of "eat a bit of everything" seems to go well with humans being omnivores and with not overdosing on any particular harmful ingredient. That was before pollution and allergies were rampant, of course.

This would seem to require that most of the 'wisdom' being embedded in the 'everything' in question.

That only makes sense in cases where you have no additional data suggesting that some foods are healthier than others.

Also, if a few foods exist which exhibit chronic toxicity at low doses, but you don't know which foods those are, wouldn't it be safer to limit the total number of different foods you consume, as to limit the chance of consuming a particularly bad one by chance? While atypical, there could be cases where the toxicity curve is relatively flat, and lower doses don't really protect you. For example, an endocrine toxin that simulates a hormonal signal even at a low dose.

It's not quite that the toxicity effects don't go to zero at low doses for things like radiation — the effects of low radiation exposure may indeed be zero. The toxicity may be zero at even relatively high doses. Rather, the value of radiation's dosage curve at the low end is stochastic, where for chemical toxins the value of the dosage curve on the entire domain is the severity of toxicity.