Sugar Molecule Links Red Meat Consumption and Elevated Cancer Risk in Mice | Hacker News Reader

Sugar Molecule Links Red Meat Consumption and Elevated Cancer Risk in Mice

health.ucsd.edu

37 pointsspankalee16 comments

Articles like this drive panic and speculation among those who don't have enough scientific competency to ascertain the significance of differences between mice and men.(humans)

https://www.quora.com/What-are-examples-of-drugs-that-showed...

The problem with the word 'cancer' and 'consumption' in biology is that it is a combinatorially complex issue.

There are many different types of cancer and many more types of gut bacteria for 'consumption.' https://www.quora.com/How-many-types-of-gut-bacteria-exist-i...

Except these mice were knockouts for Neu5Gc, making them much more like us, for purposes of this study. Also, humans and mice are both omnivorous mammals, so not radically different with regards to diet, potentially (squeak).

Correlation, not causation.

With 500-1000 identified/unidentified species of gut bacteria floating around, mimicking one is a bad data set.

Corollary example, we've not proved that H.Pylori causes Ulcerative Colitis, yet they coexist frequently.

This is not a study, this is a press release based on a study. Always, always, always go to the actual study.

The actual study is http://www.pnas.org/content/early/2014/12/25/1417508112.abst... and it is paywalled. The main thing that jumps out about it, is that it is not just a dietary intervention; they also injected the mice with antibodies to Neu5Gc, supposedly to reproduce the levels found in the human immune system. Bad things happened only to those mice who were both fed Neu5Gc (at a concentration an order of magnitude higher than humans would encounter) and also gave them these antibodies. While this looks potentially promising, the human immunology would need to be studied, and what the effect size would be for a more typical diet is completely unknown.

There's been a lot of research and people interested in grass-fed beef. I'd love to learn more about the results of this study compared to the discoveries about grass-fed beef, omega 3 and the omega 3/6 balance stuff.

On one hand you have people like this study, which did a small 1 time study indicating that there is an inflammatory effect in mice. On the other hand, you have people like Dave Asprey who have spent years testing the 'grass fed beef is less inflammatory' hypothesis in humans. One of these has a stronger indication to my own health than the others.

"Neu5Gc accumulated in the tumors."

I'm not sure that that makes sense from a biological perspective, for many reasons. Neu5Gc itself is not terribly likely to be carcinogenic, its mode of action is to enervate the immune system. If anything, accumulation of Neu5Gc in tumors should mitigate cancer by triggering antibody-directed cell-mediated cytotoxicity.

I like the fact that the there is an explicit disclosure at the end.

Also this: “Of course, moderate amounts of red meat can be a source of good nutrition for young people. We hope that our work will eventually lead the way to practical solutions for this catch-22.”

I think this is important. What amount of red meat is OK to consume? Its really hard to get people to stop eating what they've developed a taste for. But limitation would be a much more achievable strategy.

Serious question: is there any reason to think that mice would be a good proxy for human health results re: meat consumption?

Can't claim to know personally but a quick search turns up numerous results claiming that mice and rats are similar to humans in anatomy, genetics, internal processes, etc. I think they become even better candidates when you compare them to other possible test subjects, especially factoring in the cost/value. They are relatively cheap and easy to breed with almost no genetic variation (good for testing), accelerated lifespans, small, etc.

You do have to keep in mind that they're not a perfect model, though. For example, the "has been known to cause cancer in laboratory animals" label that used to be required on saccharin-containing products was removed after it turned out to be related to some unique characteristics of rodents' urinary tracts

That, and they were feeding the rats ridiculous quantities of saccharin, as I recall.

Did you even read the article?

> the scientists found that feeding Neu5Gc to mice engineered to be deficient in the sugar (like humans) significantly promoted spontaneous cancers

I don't think they're just refering to this specific study though, they're asking it in a more general term.

Mice are far from perfect proxies for humans, but when it comes to dietary and nutrition studies, they are surprisingly good matches. Others have pointed out the cost/quantity/ease advantages of working with mice. Another big advantage is that some mice (and many rats) are opportunistic omnivores, like humans. As such, their digestive systems have evolved to be reasonably similar to ours. (Key word here being "reasonably").

That makes sense. Thanks.

Let me know when you guys figure out whether or not salt is bad for me.

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