Debunked: Food emulsifiers cause colorectal cancer?

Hey everyone. Steve Milloy here. I was watching TV Sunday morning and I heard a TV host saying something about food emulsifiers causing colorectal cancer. Is there anything to that claim?
Food emulsifiers, like carrageenans and polysorbates, are food additives used to improve the texture and shelf-life of food. The Food and Drug Administration long ago classified emulsifiers as “generally recognized as safe” or GRAS. But earlier this year, an epidemiology study published in PLOS Medicine reported that, in a French population of 92,000 people, emulsifiers as a group were weakly correlated with increases in all cancers, breast cancer and prostate cancer.
Note that I used the word ‘correlated.’ Correlation just means a coincidental statistical relationship. Correlations by themselves are meaningless. If you’ve taken a statistics course, you know that mere correlation is not the same as causation. Moreover, the correlations in the study are very weak - where “weak” means not impressive enough to be even considered as evidence of causation. And when you consider that the researchers don’t really know how much of any emulsifier any study subject consumed and that the study subjects were only followed for less than 7 years on average, the weak correlations are just totally meaningless. But it gets worse.
For epidemiologic correlations to have meaning, they must be supported by biological plausibility, which is a technical way of saying the correlation must make some sort of physical sense. That smokers have a higher rate of lung cancer than nonsmokers makes sense and so the correlation has the requisite biological plausibility. But there is no biological plausibility for why emulsifiers would increase the rate of all cancers, let alone breast cancer or prostate cancer. How would that work? What would the physical mechanism be?
Recall that the issue of interest in this video is that emulsifiers were claimed to be linked with colorectal cancer. And the epidemiology study, in an effort to demonstrate biological plausibility, cites a lab rat study. Past the fact that labs rats are not little people, in that study, high doses of emulsifiers were directly injected into the rats’ intestines. The rats were then euthanized, their intestinal tissue put under a microscope, where some tissue inflammation was reported. Past the biologically implausible means of exposing the rats to emulsifiers - normally they go through the acids in your stomach first -- mere tissue inflammation is not cancer. Not even close.
But here’s the real killer of the claim we’re focusing on. The epidemiology study actually reported no correlation between emulsifiers and colorectal cancer, in the first place. And there are no other epidemiology studies that make such a link. Weak correlations with no biological plausibility are bad enough as a basis for a health scare. But no correlations and no biological plausibility is just beyond the pale. There is no credible evidence to link emulsifiers with colorectal cancer. People who make claims to the contrary area just makin’ it up.
Stay up with the latest in junk science. Follow me on X at @JunkScience and at my web site JunkScience.com. Thanks for watching.