Flashback Friday: What’s the Best Mouthwash?

The effects of a vegetarian diet on systemic diseases like cancer, diabetes and heart diseases have been studied, and revealed predominantly less systemic diseases in vegetarians, but there have only been a few studies on oral health, which I covered in previous videos… but what’s the latest? In a study of 100 vegetarians compared to a 100 nonvegetarians, the vegetarians had better periodontal conditions: less signs of inflammation like gum bleeding, less periodontal damage and a better dental home care, brushing and flossing 2.17 times a day compared to 2.02 times a day, not that much of a difference, so maybe it was something about their diet, though vegetarians may have a healthier lifestyle overall beyond just avoiding meat. They controlled for smoking, but other things like obesity can adversely affect oral health, so there may be confounding factors. What we need is an interventional study, where they take people eating the standard Western diet, improve their diets, and see what happens, but no such study existed, until now.

With professional support of nutritionists, the participants of the study with existing periodontal disease changed their dietary patterns to so-called wholesome nutrition, a diet emphasizing veggies, fruits, whole grains, potatoes, beans, peas, lentils, and spices with water as the preferred beverage. (What a concept.) To make sure any changes they witnessed were due to the diet, they made sure they maintained their same oral hygiene before and after the dietary change. What did they find? They found that eating healthier appeared to lead to a significant reduction of probing pocket depth, gingival inflammation, and levels of inflammatory cytokines, which mediate the tissue destruction in periodontal disease. So it may be concluded that wholesome nutrition may improve periodontal health. Why though? Yes, plant based diets have a number of nutritional benefits in terms of nutrient density, but it also may be about improving balance between free radicals and our antioxidant defense system.

Traditionally, dietary advice for oral health was just about avoiding sugar, which feed the bad bacteria on our teeth, but now we realize some foods and beverages, like green tea, possess antimicrobial properties to combat the plaque producing bacteria directly.

Streptococcus mutans has been identified as oral enemy #1. If plaque is caused by bacteria, why not just use antibiotics? Many such attempts have been made, however undesirable side-effects such as antibiotic resistance, vomiting, diarrhea and teeth stains have precluded their use. In a petri dish, green tea phytonutrients effectively inhibit the growth of these bacteria, but what about in our mouth? They found that rinsing with green tea strongly inhibited the growth of the plaque bacteria on our teeth within minutes. Seven minutes after swishing with green tea, the number of these bacteria in the plaque scrape from people’s teeth was cut nearly in half. So if you have people swish sugar water in their mouths, within three minutes the pH on our teeth can drop into the cavity formation danger zone. But if 20 minutes before swishing with sugar water, you swished with some green tea, you wipe out so many plaque bacteria that the same sugar water hardly has any effect at all. So, they conclude, using green tea as a mouthwash or adding it to toothpaste could be a cost-effective cavity prevention measure, especially in developing countries, because here in the civilized world we have antiseptic mouthwashes with fancy chemicals like chlorhexidine, considered the gold standard anti-plaque agent.

If only it didn’t cause genetic damage. DNA damage has been detected in individuals who rinsed their mouths with chlorhexidine-containing mouthwashes, and not just to cells in the mouth. 13 volunteers rinsed their mouths with the stuff for a few weeks and there was an increase in DNA damage both from the cells lining their cheeks as well as their peripheral blood cells, suggesting it was absorbed into their bodies. Yes, it reduced plaque better than other antiseptic chemicals, however, it might be doubtful whether chlorhexidine can still be considered the golden standard when considering how toxic it is to human cells.

So are we left with having to decide between effectiveness or safety? How about a head to head test between chlorhexidine and green tea? Green tea worked better than chlorhexidine at reducing plaque. So using green tea as a mouthwash may work cheaper, safer, and better. And if as a bonus you want to sprinkle some amla powder into it, dried Indian gooseberry powder, it evidently shows an outstanding cavity-stopping potential not by killing off the bacteria like green tea, but just by suppressing its plaque forming abilities. Here’s how much plaque is formed without amla, Here’s how much is formed with.

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Katie Schloer.

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Images thanks to treobenny via Flickr.