Xylitol: A “ Tooth friendly “ Sweetener
Xylitol is not only a safe, natural sweetener, it may also be good for your teeth.
WHAT IS IT?
Xylitol is a naturally occurring sweetener that is found in agricultural and forest products (e.g. raspberries, plums and cauliflower)and it is produced by the human body during its normal metabolism of glucose at the rate of about 10 to 15 grams daily. It is a five-carbon sugar alcohol, or polyol (chemical formula: C5 H12 O5) that can be synthesized from a number of natural products such as corn cobs or the bark of birch trees. Even though commercial xylitol is synthesized, it is considered a natural substance because its chemical composition is identical to the naturally occurring substance. It is an odorless white crystalline powder with nearly the same sweetness as sugar, but having 40% less calories. It is metabolized in the liver as a normal carbohydrate, but at a much slower rate than sucrose. Xylitol has a glycemic index of 7 as compared to that of sugar which is 64 and glucose which is 100. It has no aftertaste and also has a very pleasant cooling sensation when it dissolves in the mouth.
Xylitol was discovered in 1891 by a chemist named Emil Fischer. It was used chiefly as a research chemical until World War II resulted in a shortage of sugar in some European countries such a Finland. Finnish researchers and engineers succeeded in developing an industrial method for xylitol production on a small scale to provide an alternative. The first xylitol chewing gum was produced and distributed both in Finland and the United States in 1975. Today, is found in many products such as mints, toothpastes, mouthwashes, confections, pharmaceuticals, and dietetic and diabetic foods as well as bulk form.
HOW DOES XYLITOL WORK
Xylitol’s unique 5-carbon structure prevents many types of bacteria such as Streptococcus mutans from metabolizing it. This is the key reason that xylitol has been found to be effective in preventing or reducing cavities.
The different varieties of oral bacteria have different ways of dealing with xylitol. Some aggressive types including Streptococcus mutans eagerly gobble up the xylitol and apply their sugar-processing machinery to work phosphorylating and dephosphorylating but not getting anywhere in the fermentation process. The bacteria gives up and expels the intact xylitol (instead of the usual acid) back onto the teeth where it can be snapped up by the next unlucky bug. This “futile cycle” takes a lot of effort and ultimately decreases the number of Steptococcus mutans. The long term survivors are generally a group that just ignores xylitol and are often referred to as “xylitol-insensitive”. Over time, in the presence of xylitol this group is favored and these bacteria tend not to be very acidogenic. The usual pattern is a rapid decline of xylitol-susceptible acidogenic bacteria and a replacement by a less harmful bacterial strains that can ferment xylitol slowly, produce very little acid and gain no competitive advantage in the mouth.
A number of research studies conducted over more than 30 years have confirmed that using xylitol in the form of chewing gum from 3 to 5 times a day (about 6 to 12 grams a day) will increase the protective factors in saliva and help to maintain the pH in the safe range above 5.7. This translates into fewer cavities for individuals using xylitol daily in the recommended dosages. In Finland, an ambitious study (later known as “Turku Sugar Studies) was proposed to test the hypothesis that replacing dietary sucrose with another sweetener could reduce the incidence of tooth decay. The dental results showed the xylitol substitution group had an astounding caries reduction of at least 85%!!!
Xylitol is considered safe for human consumption and is an approved food additive. The Federation of American Societies for Experimental Biology confirmed this in a study in 1986 prepared at the request of the U.S. Food and Drug Administration, which approved its uses as a sweetener in 1963. The Joint Expert Committee on Food Additives not only verified that xylitol was safe for humans, but also discounted adverse findings in a 1970 animal study by stating that a review of the results were found not to be relevant to humans. This committee, which is an advisory body to the World Health Organization and the United Nations, allocated an Acceptable Daily Intake of “not specified” which is the safest category that a food additive can be given. In addition, the European Union has accepted xylitol as acceptable for human dietary use. According to the American Society for the Prevention of Cruelty to Animals Poison Control Center, xylitol, when ingested by dogs, can pose a considerable risk of toxicosis to them due to an increase of blood insulin levels that results in significantly diminished blood glucose levels.
There are some minor disadvantages to using xylitol. Xylitol is not currently available in the pharmacies and grocery stores in Canada. As a result, the dental office or the internet will have to be the main supplier of the products for patients needing the dental benefit. If xylitol has never been used before, ingesting a large amount at one time (approximately 100 grams) may result in temporary gastrointestinal discomfort. However this problem disappears quickly because the body not only produces xylitol during normal metabolism but also produces the enzymes necessary to break it down. The gastrointestinal discomfort is not a concern when xylitol is used at the dental recommendation of 6 to 12 grams daily.
Xylitol and Oral Health
Tooth decay and gum disease are serious problems for many people. Studies have proven that as many as 75% of adults over the age of 35 suffer from some form of periodontal disease. Needless to say, diet plays a major role in dental health. When there is an excess of sugar in the diet, this weakens the immune system and creates an acidic environment; thus oral health suffers. The mouth is home to over 400 strains of bacteria. Most these are benign, but when sugar enters the scene, it feeds the destructive strains, allowing them to proliferate.
Periodontal disease is basically caused by bacteria. These deposits permit the growth of bacteria that cause inflammation of the gums. The bacteria also release minute amounts of toxins that break down tissue, thereby helping the infection to progress. Plaque is an invisible, sticky film of saliva and food residue that constantly forms on the teeth. Ongoing low-grade bacterial infection also burdens the immune system.
Bacteria help to create plaque and they also thrive within it. Unless removed, plaque formed along the gum-line can lead to gum disease. When left untreated, plaque at or below the gum-line hardens into tartar. Periodontal disease takes two forms: simple gum inflammation, called gingivitis, and a more severe gum infection, called periodontitis, which may lead to tooth loss and receding gums. Gum infection can also lead to other serious health problems.
Eating sugar causes tooth decay by creating a highly acidic condition in the mouth. Acidity strips tooth enamel of minerals, causing it to weaken and making it more vulnerable to attack by bacteria, leading to tooth decay or demineralization. Ordinarily, saliva bathes the mouth with an alkaline solution that neutralizes all acidity and actually remineralizes the teeth. Saliva also washes away leftover bits of food and helps the digestion process. But when saliva turns acidic because of too many sweets, bacteria in the mouth have a feeding frenzy. These nasty bacteria, along with carbohydrate waste, stick to the teeth and tongue and hold the acid close to the teeth where it eats away enamel. Virtually whatever food you ingest, the remaining particles become food for plaque-producing bacteria. Using xylitol helps to raise plaque pH, thereby reducing the time that teeth are exposed to damaging acids, as well as starving harmful bacteria of their food source.
Xylitol is non-fermentable and therefore cannot be converted to acids by oral bacteria, thus it helps to restore a proper alkaline/acid balance in the mouth. This alkaline environment is inhospitable to all the destructive bacteria, especially the worst variety, Streptococcus mutans. It also inhibits plaque formation.
Regular xylitol use leads to lower plaque accumulations. Xylitol forms weak interactions with calcium in solution, helping to prevent precipitation. This stabilizing effect of xylitol make salivary calcium available for remineralization of enamel while slowing the rate of tartar formation. Less placque is, by itself, a useful xylitol effect.
Using Xylitol right before bedtime, after brushing and flossing, protects and heals the teeth and gums. Unlike sugar, it can even be left on the teeth overnight. With proper use, xylitol actually stops the fermentation process leading to tooth decay. Long-term use suppresses the most harmful strains of oral bacteria, making a long-lasting change in those bacterial communities.
Consistently using small amounts of xylitol tends to increase protective factors in saliva. Xylitol stimulates saliva flow and helps keep salivary minerals in a useful form. Prolonged xylitol use increases the buffering capacity and protective factors in saliva. Increased saliva protection is especially important for people suffering with a dry mouth due to illness, aging, or drug side-effects.
Since the oral environment becomes less acidic with continued xylitol use, it is advisable to chew xylitol gum or suck a xylitol mint after every meal or after eating sweet snacks. The best news is that studies have shown that xylitol’s effect is long-lasting.