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Comment by bmeski | Hacker News Reader

I have a degree in the biomedical sciences and I often see CS majors/software/math folks insert clear cut divisions between terms and things than could possibly correlate.

I feel like a lot of people don’t understand how continuous certain parts of biology are (and aren’t).

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Different human populations have different microbiomes. Different mouse strains do too (presumably rats as well). Never mind the other (significant) differences between mice/rats and humans, wrt nutrition. The fat and protein content of rat milk is quite different to that of human milk, for example (yes, early development in these animals is also quite different, so it's not a simple "they need high protein, we need low" story -- it's just an example of the kind of meaningful differences that exist).

So I think it's pretty important to note "this is just in rats so far". It doesn't mean 0 predictive power. But it's far from solid that the effect transfers to your average US citizen, for example. IMO, these types of animal studies are useful guides for further (hopefully human) research, but shouldn't influence your day to day behavior, or the choices you make for your child. There's ample reason to avoid empty calories from sugar for pure nutritional reasons anyway, based on human studies.

But what is the likelihood that this result applies to humans vs. doesn't apply to humans? It doesn't sound like you can say. There are also differences even between two different humans. Simply being different is not enough to discount a result using a model that has otherwise proven successful.

I'm absolutely confident I can discount it in the sense of "reduce its predictive power" compared to a study in humans, but I already said I'm not discounting it in the sense of dismissing it entirely.

> It doesn't mean 0 predictive power.

BTW, I also think that most of the time you shouldn't change your daily behavior based on one single human study.

I have a degree and I'm extremely suspicious of any study that wants to extract strong statements from only experimental evidence connecting (1) a very basic ingredient of just about any foodstuff (2) the gut microbiome and (3) "memory function" as only observed through further experiments.

You could make your career from studying just tiny tiny parts of 2 or 3 but instead we got a study that is trying to solve for the world.

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