Xylitol:  Sweet Answer to Healthy Teeth

    Xylitol is a natural sweetener found in many fruits and vegetables.  It was discovered in 1891 and has been used as a sweetening agent in food since the 1960s.  The human body also produces it during normal carbohydrate metabolism.  It is a white, odorless, crystalline powder with a pleasant, sweet taste.  It has the same sweetness as sucrose, but with 40% fewer calories.  The cooling sensation created as it dissolves makes it a great sweetener for many  types of products.  Xylitol is presently approved for use in foods, pharmaceuticals, and health products in 35 countries.  It is used in chewing gum, mints, hard candies, and in other health care products such as throat lozenges, cough syrups, children's chewable multivitamins, toothpastes and mouthwashes.  In the US, xylitol is approved as a direct food additive for use in dietary foods.

     The importance of xylitol in dentistry became evident almost 40 years ago when a study showed that the consumption of xylitol caused a sharp reduction in the formation of dental cavities, even for those individuals who brushed and flossed religiously.  Since that time numerous clinical studies have attempted to determine how and why xylitol can help prevent tooth decay.

     It has long been known that pathogenic bacteria (primarily mutans streptococci) cause cavities by fermenting sugar and producing acid.  They also make a sticky polysaccharide that holds the acid and bacteria on the surface of the tooth, forming a cavity producing biofilm (commonly referred to as plaque).  Studies have shown that when xylitol is used as a sweetener, the mutans streptococcus cannot ferment this sweetener to form acid nor can it produce the sticky polysaccharide.  Because the bacteria can no longer make the glue that allows them to stick to teeth, the pathogenic bacteria are more easily brushed off the teeth and more easily washed off by saliva.  So with xylitol, acid and polysaccharide are not produced and the number of mutans streptococci in the biofilm declines substantially.  The remaining biofilm is a healthier mix of beneficial or at least harmless bacteria.  The result is a dramatic reduction in the number of dental cavities.

     Children acquire the decay-causing bacteria from their mothers (vertical transmission) via shared utensils, kissing, etc.  Studies have shown that if mothers start consuming xylitol when their babies are young, there is little transmission of bacteria to infants and therefore a much lower rate of tooth decay.  In one study, mothers started chewing xylitol gum three months after delivery and continued for 21 months.  Their children (who never consumed xylitol) had much lower levels of mutans streptococci and greatly reduced tooth decay (70%) compared to children whose mothers never consumed xylitol.  This benefit continued for up to 4 years after the children's mothers discontinued xylitol consumption.  Another study involved women consuming xylitol starting at the sixth month of pregnancy and continuing for 13 months.  Again, the results were a lower rate of transmission of bacteria from mother to child.  Maternal xylitol consumption is therefore a wonderful way to start your newborn off with healthy teeth.

     Most of the early studies on xylitol consumption and tooth decay were carried out with xylitol gum.  Since chewing gum elicits an increase in salivation, it was uncertain if the xylitol or the stimulated saliva flow accounted for the decrease in decay rate.  Increased salivation does exert a cleansing influence on teeth, has a buffering effect on the bacterial acids, and results in an increase of calcium and phosphate, which causes a healing or hardening of tooth enamel.  This question was answered when chewing gums sweetened with different sweeteners were compared in a field study of 4th-grade students in Central America.  The highest decay rate was found in children who chewed sugar-containing gum, even higher than those children who did not chew gum.   Sugar-free gum did  lower the decay rate, but the most dramatic drop in the decay rate was observed in children chewing 100%-sweetened xylitol gum.  

     Another study involving 10-year-olds in Estonia compared the efficacy of xylitol candies and xylitol gum in reducing tooth decay to a control group that did not consume xylitol.  The results for the candy and gum were the same:  both reduced tooth decay by 35 - 60%.  So xylitol appears to be the key in reducing decay whether in candy or in gum.  Even when present in toothpaste with fluoride, the results showed a greater reduction in tooth decay when compared against regular fluoride toothpaste.

     The question of how much xylitol and how frequently it needs to be consumed was confirmed at the University of Washington.  Their results showed that increasing doses of xylitol caused an increasing reduction in mutans streptococci with the effect leveling off between 6.88 grams per day and 10.32 grams per day.  A dose of 3.44 grams per day had only a slight effect.  A follow-up study indicated a frequency of at least 3 times per day was necessary for clearly observable results.  Therefore consuming xylitol at least three times a day for a period of at least 5 minutes per episode to a total dose of 6 - 10 grams per day will cause a substantial decrease in mutans streptococci levels, does not alter the overall normal oral bacteria, and results in a concomitant substantial reduction in tooth decay.

     Xylitol  use has been shown to be safe for consumption even by infants and nursing mothers.  The main side effect is diarrhea and that only occurs at levels 4 to 5 times the dose recommended to reduce tooth decay.  In fact, xylitol is recommended and used in diabetic foods because it is absorbed slowly and has a low glycemic index (it does not cause a rapid increase in blood glycose).  In addition, children who take xylitol have been reported to experience 40% fewer middle ear infections.

     The health benefits of xylitol have not been overlooked by the market place.  There has been an explosion of new products that claim the use of xylitol as a sweetener.  However, many of these products do not contain enough xylitol to prevent tooth decay.  After all, xylitol is much more expensive to produce.  Furthermore, most products do not state the amount of xylitol they contain, making it impossible to know how much product to consume to maintain great dental health.  Therefore only products that state explicitly the exact amount of xylitol present (preferably 100% xylitol) should be purchased.  www.epicdental.com and www.drjohns.com are two websites that are useful in this regard.

     One's goal in the mouth, as well as in other areas of the body, is to cultivate a healthy protective biofilm (probiotics).  Last year, research out of UCLA showed that a healthy, normal oral biofilm does indeed greatly reduce colonization by mutans streptococci.  Xylitol can be used to selectively reduce mutans streptococci and to yield such a beneficial biofilm.  By consuming xylitol at least 3 times a day for at least 5 minutes per consumption, to a total dose of 6 - 10 grams per day, the result will be fewer cavities and a healthier dentition.

     Incidentally, even though xylitol is safe for humans, it can be extremely harmful and even fatal for dogs

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