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@ The Dread Slender Gnome
2025-02-23 10:23:56
(I intended to just write a couple of lines, but then ended up geeking out about it... so, long post.)
My point is that there's loads of attention paid on cardio-vascular diseases and their contributors in Finland, because it's such a problem. And that lots of attention has also been paid on xylitol there. That not even an inkling of a connection has cropped up makes me start out skeptical of big claims such as this one.
So I tried to do searches on this, but came up with VERY little further info. Partially because the articles tended to be behind paywalls.
What I did come up with is that the research talked about xylitol (or its derivatives) in the blood stream. However, that was apparently in reference to foods and drinks sweetened with xylitol. Several people pointed out that we don't know to what extent xylitol in a chewing gum translates into xylitol in blood stream, as chewing gum is typically not swallowed. And expert from the article Feart linked said, also referring to tablets, " [i]n fact, the majority of xylitol is not absorbed but is excreted in the feces". If xylitol is not absorbed, it or its derivatives can't show up in the blood stream either. The article also states "[t]he study unfortunately did not assess how much xylitol was consumed by the subjects". This is very important, because dose always makes the poison. I should note here, that to the best of my knowledge, xylitol has not been a very popular sweetener for foods and drinks in Finland, presumably because it's not as sweet as others. Sugar-free products typically list other sweeteners, and my impression is that most xylitol would therefore have been consumed as chewing gum.
Now, for the study itself. It seems I only have access to the abstract, and frankly it raises more questions than it answers.
The introduction specifically mentions "[l]ow-calorie sweeteners are widely used sugar substitutes in processed foods". So we are talking about xylitol as consumed in foods and drinks, not used in chewing gum or tablets. This matters, because they're talking about its effects in the blood stream, and for that, absorption matters.
This is a badly written and unclear abstract.
The methods mention human blood sample analysis, platelet and blood response analysis, and animal models. And a study on "effects of xylitol consumption on platelet function". They say they took blood samples from a cohort undergoing elective (!) diagnostic cardiac evaluations, and also on an independent validation cohort, though they seem to imply the procedures done on the latter samples weren't the same as those done on the first set. It does NOT seem to mention them taking histories, or following up on patient outcomes in any way.
In addition, they did analysis on platelet and blood behaviour, and had an animal model for testing the incidence of actual C-V events.
Now the results. Here's the thing. I can't see where they got the connection from their methods to their stated results. The first sentence reads: " In initial untargeted metabolomics studies [...], circulating levels of a polyol tentatively assigned as xylitol were associated with incident (3-year) major adverse cardiovascular event (MACE) risk". This SOUNDS like they observed the outcomes of the patients, or took careful histories in addition to blood samples. But the methods mention neither. And if they're relying on histories to produce this effect, how can they be confident that the xylitol metabolite levels were on the same level in the patients at the time of their C-V events?
Now they do say they found actual increase in C-V events in their animal model. I'll give them that. And I have nothing against using animal models as a basis. But it seem they have taken the animal model results AND the C-V cohort mentioned above, and used them together to state that xylitol unequivocally raises C-V risks, and to imply that this is the case in humans. They do also mention interventional studies showing a change in plasma behaviour in subjects taking xylitol-sweetened drinks, and are probably using that as further support. But again, note that it was drinks, not mouth-health products such as chewing gum or tablets.
As for the conclusions, much like the title of the article, they make a very bold claim of established association, without caveats. I was taught that this is bad form, even taking into the account the limited form of an abstract. The one sentence in the conclusions I can agree is supported by the information provided in the abstract is "[f]urther studies examining the cardiovascular safety of xylitol are warranted".
And then the obvious point. This is one (1) study. All the articles I found appear to be referring to this single study.
One study is always just one study. Until this effect is repeated multiple times, I'm not going to conclude more than "further research is warranted".
(now I'm out of letters)