Recent comments in /f/science

1thenumber t1_jbc5c0m wrote

Epidemiology cannot speak to causation, so you are jumping too far ahead. It can generate a hypothesis that can then be tested in a controlled trial. But asking people to self-report on habits over a long period is not going to tell us cause; it is going to tell us what every similar study does - that healthy people are healthy, and unhealthy people are unhealthy.

The healthy group in this case might be simply healthy because they care about being healthy - they are "adherers" or "compliers". There's a really fascinating study that was done in 1980 on a cholesterol drug called clofibrate, where the initial results were unspectacular when compared to placebo. The clofibrate showed no improvement over the placebo group in terms of mortality.

However, when those two groups were split again between "adherers" and non-adherers, the adherers in BOTH groups saw almost the exact same reduction in mortality that the mouthwash study saw - about 50%. This means in a placebo group, where no actual intervention was being taken, simply adhering to the instructions given by the study was enough to almost halve your mortality risk.

https://www.nejm.org/doi/full/10.1056/NEJM198010303031804

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UterineTemple t1_jbc3guc wrote

Oh dear, would not Xylitol hurt your gut flora if taken orally? I assume if used for just mouth washing it's not so bad, but there are loads of studies praising the role of healthy gut bacteria.

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CogitusCreo t1_jbbzt9d wrote

This study didn't dig that deep, but a similar study about alzheimers and oral hygiene speculated that bacteria can enter the bloodstream and end up in the brain. I think they may have been looking at the use of mouthwash with xylitol. I can't find that exact study now, but you might like these:https://www.sciencedaily.com/releases/2019/04/190407144231.htm

https://www.nia.nih.gov/news/large-study-links-gum-disease-dementia

Edit: I'm talking about mouthwash below. Edit 2: Keep xylitol away from your dog! It's fatal to them.
Xylitol is great, BTW. A scientist friend of mine said that bacteria absorb it like sugar, but can't metabolize it, so they die (that may be a massive oversimplification). More info here: https://orlcares.com/blogs/orl-cares-blog/exploring-the-science-behind-xylitol-s-cavity-fighting-power

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