Dear Doctors: The whitening toothpaste I’ve been using for several years has a pleasant flavor and keeps coffee from staining my teeth. But I just realized it contains xylitol, which I’m hearing can cause heart problems. Do you know if this is true? Do I need to switch?
Dear Reader: Xylitol is an artificial sweetener that falls into a category known as sugar alcohols. Also known as polyols, these compounds contain neither ethanol -- that’s alcohol -- nor sugar. Rather, they are a form of carbohydrate with a chemical structure similar to sugar. In fact, their structure so closely resembles sugar, it triggers receptor proteins on the taste buds that are involved in identifying the flavor of sweetness.
Once activated, those proteins release molecules that stimulate nearby neurons. Signals travel to the region of the brain involved in taste, which interprets sweetness. In an interesting side note, cells from the sweet taste receptor system are scattered throughout the gut. They can detect nutrients and can tell the difference between natural and artificial sweeteners. Some researchers suspect that may play a role in why foods with artificial sweeteners can trigger rather than sate sugar cravings.
Sugar alcohols have from one-half to one-third the calories of natural sugars. Because they are metabolized slowly, they don’t take the same toll on the body’s insulin response as sugar. This has led to their widespread use in diet products, in foods suitable for people living with diabetes and for low-carb diets, such as keto. They are commonly used in diet sodas, sugar-free gum, baked goods and candy and even in some mainstream products.
From the moment these sugar substitutes reached the marketplace, they became a subject of study, debate and also controversy. Polyols occur naturally in small amounts in some fruits and vegetables. But for commercial use, they are lab-made. And as they find their way into a growing array of foods, the increasing intake per person is raising concerns. Investigations into various forms of sugar alcohols have found they can cause gastrointestinal problems such as pain, bloating, flatulence and diarrhea. Two years ago, an observational study linked them to an increased risk of heart attack and stroke.
And that brings us to a new study of xylitol, which pinged your radar. Published in the European Heart Journal, it analyzed blood samples from 3,300 participants who had completed an overnight fast. The researchers analyzed health data three years later, and they found that individuals with the highest blood levels of xylitol had twice the risk of having a heart attack or a stroke as participants with the lowest levels. The risk of death had also doubled.
As always, it is important to note that while an observational study can suggest a connection between certain factors, it can’t prove cause and effect.
In our own practices, we suggest artificial sugars should be used in moderation, and as a temporary aid. Toothpaste is not a significant source of xylitol and should not cause concern. However, if you are worried, you can switch to a natural toothpaste, some of which also have whitening varieties.
(Send your questions to [email protected], or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)
