A 2002 UCLA study found that consuming excessive amounts of sugar reduces the production of the brain chemical called brain-derived neurotrophic factor, or BDNF. “Without BDNF, our brains can’t form new memories and we can’t learn (or remember) much of anything,” according to an article in Forbes
Another study from the University of Copenhagen found that low BDNF levels are linked to depression and dementia. What’s more, when BDNF levels are reduced, the body begins to become resistant to insulin, which kicks off a cascade of other health problems. But there’s a more immediate problem from consuming too many sweets: According to a 2010 study from the University of Minnesota, chronic sugar consumption dulls the brain’s mechanism for knowing when to stop eating.
Sugar is not the only harmful substance in soda that affects dental health. A 2006 study published in the Academy of General Dentistry journal found that drinking soda is nearly as harmful for your teeth as drinking battery acid. That’s because soda actually contains acid (most commonly citric and/or phosphoric), which corrodes tooth enamel. And with a pH of 3.2, diet sodas are even more acidic than regular sodas. According to the Colgate Oral and Dental Health Resource Center, soft drinks are among the most significant dietary sources of tooth decay. “Acids and acidic sugar byproducts in soft drinks soften tooth enamel, contributing to the formation of cavities. In extreme cases, softer enamel combined with improper brushing, grinding of the teeth or other conditions can lead to tooth loss.”
Recent research has shown a correlation between soda consumption and heart disease. Most recently, a 2012 Harvard study found that one daily 12-ounce serving of regular soda “was linked to a 19 percent increase in the relative risk of cardiovascular disease,” according to the New York Times. Some researchers say the blame can be placed on high fructose corn syrup, which has been linked to an increased risk of metabolic syndrome, a condition associated with an elevated heart disease risk. However, others say diet sodas with artificial sweeteners are much worse on the heart. A study from the University of Miami found that those who had a daily diet soda habit had a 61 percent increased risk of “cardiovascular event,” including heart attack and stroke, than those who drank no soda — even when factors such as smoking, physical activity, alcohol consumption and diet were controlled.
A recent study by the University of Adelaide found that drinking too much soda can increase the risk for developing asthma or chronic obstructive pulmonary disorder, or COPD. The more soda a person consumes, the greater the risk of developing those diseases. Other studies suggest sodium benzoate, a preservative in soda, may directly affect the lungs: It increases the amount of sodium in the body while reducing the availability of potassium, causing asthma as well as eczema.