Polyphenols and probiotics for oral health? Original paper

In this narrative review, various polyphenols and the probiotic Lactobacillus reuteri were associated with a reduced risk of dental cavities, oral infection, and oral cancers. However, most evidence was collected from cell studies, animal studies, or nonclinical human studies.

The effects of polyphenols or Lactobacillus reuteri on the risk of dental cavities or oral cancers.

Many of the reviewed studies were performed in vitro (e.g., in human cancer cells^[1]) or in animals (e.g., in rats^[2]). Some of the included studies were conducted with human participants.^[3]

As examples, some in vitro studies assessed the effect of epigallocatechin gallate extract when applied to cancer cells.^[1] Some animal studies treated rats with resveratrol to reduce dental root resorption^[2]. The human studies tended to be observational studies or other narrative reviews (rather than randomized controlled trials or meta-analyses).

For example, a narrative review on general dietary consumption of berries (for berry polyphenols) for cardiovascular disease and esophageal cancer was included.^[3] An example of an included randomized controlled trial tested the effect of supplementing with Lactobacillus reuteri on the oral microbiota (bacterial species profile).^[4]

Numerous polyphenols were associated with health outcomes ranging from cardiovascular disease to various cancers. For example, one pilot study found that the equivalent of 10 cups of green tea per day reduced the risk of recurrence of colorectal adenoma by 51%.^[5]

Some polyphenols may reduce risk of dental cavities. For example, certain isoflavones produce hydroxyl compounds that are very reactive to certain microorganisms such as Streptococcus mutans. This bacteria can ferment sugars in food particles that are stuck to the teeth, producing acid, demineralizing the teeth, and creating dental cavities.^[6]

For Lactobacillus reuteri, there was some evidence for improved oral health. For example, one randomized controlled trial found that supplementation with this probiotic induced general positive shifts in the oral microbiota. However, the biological relevance of these changes are not firmly established.^[4]

Polyphenols encompass a wide variety of plant compounds, from the resveratrol found in grapes and red wine to the procyanidins found in cocoa and dark chocolate).

Lactobacillus reuteri is a widely studied bacteria (probiotic) that naturally occurs in the human body and is commonly found in the mouth and other parts of the gastrointestinal tract.^[7]