The point is that this particular study was not simply an association study. It is one of the very few that adds prospective experimental investigations to examine the causation of the observed association.

With respect to the toxicity of xylitol for dogs: It is unlikely that a different absorption rate is the cause. In dogs, xylitol peaks after about 40 minutes of consumption with symptoms appearing within 1.5 hours.

In comparison to humans, xylitol causes a spike in insulin secretion leading to dose-dependent hyperinsulinemia and hypoglycemia. It also leads to a depletion of ATP in hepatocytes which, if sever enough, causes necrosis of liver cells. The hypoglycemia is the main reason for the observable symptoms of xylitol poisoning in dogs.