One of the major issues regarding the safety of soft drinks is their adverse effect on teeth due to the acids present as well as the sugar content in them. While frequent mouth washing can remove most of the sugar adhering to the gums and the teeth, acids are supposed to be corrosive causing tooth erosion and hyper sensitivity. Many campaigns of the past against Cola giants Coke and Pepsi were based on the presence of the mineral acid phosphoric acid in the formula which is considered one of the most corrosive chemicals. In other synthetic flavored drinks, organic acids like citric, malic etc are used and many feel comfortable because of their belief that these acids are mild and non-corrosive. But this may be a misplaced hope if the findings by some researchers are taken at their face value.
Carbonated non-alcoholic beverages are generally sweetened, flavored, acidified, colored, artificially, carbonated and some times chemically preserved. In such beverages sugar concentration can be between 8-14% while acid levels may vary from 0.1% to 0.2%, the pH range being 2.6-4.0. In aerated drinks CO2 itself lowers the pH by dissolving in the syrup at the low temperature used in processing while addition of acids like phosphoric, citric,fumaric, tartaric and malic acids, is common. Sports drinks are specialty products targeted at athletes and other personnel engaged in heavy exercises regularly for more than an hour each day. They are mostly isotonic solutions containing 5-7% glucose and optimal levels of electrolytes designed to recoup water and nutrients lost through sweating during the work out. Some drinks are hypotonic while few hypertonic drinks are also available for use under certain conditions. Sweating is a natural phenomenon that is intended to maintain the body temperature constantly at 37 C and significant amounts of water and nutrients are lost during sweating. 2% loss in body weight during sweating can cause impaired performance, 4% loss reduces work capacity, 5% loss results in heat exhaustion, 7% loss can create hallucination and 10% loss leads to circulatory collapse and heat stroke.
A typical male athlete has 90 gm of glycogen stored in the liver while the muscle stores another 400 gm of glycogen. During vigorous exercise body loses 3-4 gm of glucose per minute and prolonged exercise an deplete the glycogen level severely which may take 24-48 hours to replenish. Normally 300-400 ml of sports drink is consumed in a day with 5-6 sips every 15 minutes, creating a situation where the teeth are in constant contact with the beverage for prolonged time and their consequent erosion over a period. Erosive Tooth Wear (ETW) is a common dental disease condition, different from caries as the former affects only the enameled surface of the teeth. Appearing as a yellow patch at first ETW can dissolve the minerals in the dendrite underneath and cause considerable damage, eventually leading to loss of the tooth, unless treated properly. The reported finding that citric acid present in the sports drink can cause ETW is based on studies conducted on Cow teeth which was immersed in sports drink for 75-90 minutes and evaluating its impact. Whether these results can be applied to human beings and how far they will be realistic require deeper consideration. It is debatable whether any athlete will keep the drinks in the mouth for such a long time to have ETW and validation is necessary through actual human studies to subscribe to such a conclusion.
It is rather scary when one hears that 45.9% of American children have ETW of varying severity and such tooth ailments in early phase of growing, can have serious health consequences at later stages in life. As a precaution drinking soft drinks or juices with a straw and not swirling the drink in the mouth before swallowing will reduce the chances of prolonged contact with the teeth significantly. Brushing immediately after drinking a beverage can cause further damage as most tooth pastes are abrasive in nature. Frequent consumers of soft drinks, who cannot chuck this undesirable practice, are better advised to use neutralizing/remineralizing tooth paste to help re-hardening of the soft enamel.