The unhealthy effects of carbonated drinks is not in the carbonation per se, but instead in other additives, namely, fructose, phosphoric acid, and sugar substitutes. Such drinks can also push healthier drinks, such as milk, and healthier sources of fructose, such as fruit, out of the diet. Carbonated drinks are also commonly a source of sodium. This is not to say that a healthy carbonated drink is not possible. For example, according to a McGill University study, carbonated mineral water with high levels of calcium and magnesium and low levels of sodium are available to consumers and would make for ideal carbonated drinks.
Carbonation
Carbonation comes from the dissolving of carbon dioxide (CO2) in water. Despite common misconceptions, carbonation is not the harmful element in carbonated drinks. The CO2 creates carbonic acid, but this is mild enough to be insignificant even in the role of tooth enamel erosion. (The stronger acids added to some sodas are another matter.)
Some think that, since we exhale CO2 from our lungs, ingesting CO2 in another form must be toxic. However, gas is absorbed very slowly through the walls of the gastrointestinal tract, at a lower rate than CO2 is created by normal metabolism in the cells and respired out of the lungs. In other words, ordinary metabolic processes are in place to get rid of CO2 at far faster rates than it can be ingested through the gastrointestinal tract.
Acid
Carbonated drinks often contain added acid. The stomach, however, is much more acidic, with a pH around 1 or 2. This overwhelms the acidity of any carbonated drinks, which get down to a pH of about 3 when phosphoric acid is added. A pH of 3 is only a tenth as strong as a pH of 2.
Before the acid of sodas reaches the stomach, it does pass through the teeth, however, which are eroded by a pH of less than 5.2. Having a pH as low as 3, soda has a corrosive effect effect on tooth enamel 100 times that of carbonated water.
Fructose
The true culprit of carbonated drinks is not the carbonation, but instead a fruit sugar called fructose. Fructose is quickly taken up by the liver, where it is turned into fat. Aside from increased fat levels, an Israeli study in the August 2009 Journal of Hapatology reported that fructose also leads to cirrhosis of the liver and liver cancer. Far better is to eat fruit whole, because fibers in the fruit inhibit fructose absorption into the liver.
A study reported in the British Medical Journal in January 2008 even linked the increase in gout in recent decades to the fructose in soft drinks.
Sugar Substitutes
Fructose in sodas is bad; unfortunately, diet drinks are no refuge. Sugar substitutes break down into toxins. For example, aspartame breaks down into the toxin formaldehyde. Formaldehyde is linked to breast cancer, damage to memory proteins in the brain, and multiple sclerosis.
Another artificial sweetener, sucralose, is glucose with three chlorine atoms attached. The idea is that this chemical form of glucose is not digested. According to the FDA, 11 percent to 27 percent of sucralose is digested. The Japanese Food Sanitation Council asserted in January 1999 that up to 40 percent of sucralose is digested, which means your body is processing glucose and the toxin chlorine.
Another artificial sweetener, saccharin, is a much older sugar substitute. Despite going through a phase of being considered a carcinogen, the U.S. National Institute of Environmental Health Sciences has removed it from a list of known cancer agents. It is now believed to be what proponents claim sucralose is: a sugar substitute that does not break down in the human body.
More Soda, Less Milk
Caffeine leaches calcium from the body. Furthermore, if a youngster is drinking lots of soda, milk is likely being pushed out of the diet. Carbonated drinks have been blamed for reducing calcium and weakening bones, but the problem is not carbonation per se, but instead the caffeine in sodas and the milk-avoidance that goes along with drinking carbonated drinks.
