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Comment by olalonde | Hacker News Reader

Excerpt from a book I just read, The Renaissance Diet 2.0:

> What about all those cancer studies [about artificial sweeteners] in rats? The first study that initiated this scare was done in the 1970s, and saccharin at high doses was found to cause bladder cancer in rats. Pretty scary, except that in the early 2000s, it was shown that this reaction to saccharin was unique to rats and mechanistically impossible in humans. To illustrate the point, it has also been shown that vitamin C increases tumor growth in rats and mice, but does not seem to have tumor growth effects in humans.

Just sharing as a reminder that studies on animals do not necessarily translate to humans.

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The translation rate is surprisingly bad.

> Analysis of animal-to-human translation shows that only 5% of animal-tested therapeutic interventions obtain regulatory approval for human applications

https://journals.plos.org/plosbiology/article?id=10.1371/jou...

The "badness" of that number depends on the base rate. The base is getting to regulatory approval by doing exploratory studies on humans tissue (you can't ethically do exploratory studies on human subjects).

If the base rate is 0.5%, then 5% is an order of magnitude improvement and pretty good. If the base rate is 4%, then 5% is pretty bad.

I would suspect that the base rate is far below 0.5%.

But we're not comparing our excitedness about reading results in rats to our excitedness about reading results in human tissue. We're just trying to decide how excited we should be about the rat headlines.

The saccharin research was on both mice and rats, and to this day the jury is still out on manufactured sweeteners and their health impact.

Of course animal models "don't necessarily" translate; a first year med student knows that. Mice are still an excellent model as a step moving closer toward human trials because mice are incredibly similar to us physiologically and genetically, and we have a great deal of understanding about those similarities and differences.

Half the article discusses the challenges involved in trying to move beyond the mouse model to study the phenomenon more.

Do you have a credible source on that? According to the same book:

> The safety of aspartame (a commonly vilified sweetener) is asserted by the independent medical governing bodies of more than 90 countries. It has almost unanimous approval for safety by the top medical and drug safety councils in the world. The FDA has pronounced that aspartame is “one of the most thoroughly tested and studied food additives the agency has ever approved.” The story is much the same for all other major artificial sweeteners, including sucralose, acesulfame potassium, and saccharin. A large amount of calorie-free sweetener can be consumed before an even mild health risk.

The process for such approvals is time and resource intensive. And yet, we have a new & improved artificial sweeteners every few years. Yes, I know the argument... the newest one tastes better. They said the same thing about new Coke.

Seems somewhat odd that something as simple as a sweeter needs to be re-engineered so often.

They are probably re-engineered by different companies so they have a monopoly on that product for the lifetime of the patent. Could also have a different chemical profile in terms of application and taste.

I guess it is like car tires. One variety could service most and it could be made by a single company but every tire manufacture has their own angle.

How is it simple? It's the most obvious taste in most foods or drinks it's in, so any minor change is very obvious

What's odd about it? I'm not sure I understand what you are implying.

We don't get a new salt every X years. And that doesn't need to be tested and approved.

* Just a loose example, you can come up with your own additive or whatever.

p.s. For context, I have bad reactions to Aspartame. It took me a couple exposures to figure it out, with the last one nearly landing me in hospital. I certainly understand that nothing engineered is 100% safe. Nonetheless, I have personal experience with one of the "safe" sweeteners.

So you feel like the companies releasing new artificial sweeteners are wasting their money because there is no real demand for them?

> I certainly understand that nothing engineered is 100% safe.

Nor are non-engineered foods. There exists people who have allergies for virtually any type of food.

I'm saying that in order to introduce a new *artificial* sweetener, it is *very* resource intensive.

I'm saying that, if something was maybe showing sing of being "not safe" there's incentive to move on to something new sooner rather than later. That is, if exposure over time to A adds up, then it makes sense to want to move on from A to B sooner rather than later. Else A's flaws are going to be exposed.

Look at statins. The Healthcare Industrial Complex pushed those HARD. And then eventually it was, "Oh wait. These might not be as safe and as positive as we thought..." Then suddenly that push got pushed under the rug as if it never happened.

The irony of it all? We keep getting new & improved artificial sweeteners, and waistlines keep expanding more and more.

One can just look at the average American and the drink in their hands and pretty easily draw conclusions.

> To illustrate the point, it has also been shown that vitamin C increases tumor growth in rats and mice, but does not seem to have tumor growth effects in humans.

Worth noting that regular (non-GMO) mice can synthesize their own vitamin-C without needing it "pre-made" in their diet, unlike [clarification-edit: some but not all] primates (i.e. humans) and sporadic clusters of animals.

In other words, there are already some pretty important differences between how the two species process normal amounts of that nutrient.

Humans are the only primates that can't make their own vitamin c.

Inability to make vitamin c is a rarity among mammals.

Humans aren't the only primates with this trait. It's all the Haplorhini.

It's yet another thing this kind of lay audience doesn't understand about the scientific process. What should you take from studies like this? Nothing. They probably shouldn't even be getting shared to Hacker News. They're conducted because we can't experiment using novel compounds directly on humans until we've shown there is some reason to do so first. Finding an effect on mice is such a reason. This type of research is published for the sake of other researchers, who can now see if the effect is also seen in humans.

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