Summary
I occasionally suffer from advice on the consumption of diet cola drinks, warning me of negative health effects. This is intended to provide me with a summary of information to point others to when I get in these arguments. Most of this is quickly cribbed statements from reliable sources. I didn’t include source citations, but if you want to copy and paste a sentence into google, you’ll find a source.
<tldr>Almost everything bad you’ve heard about diet soda is from attention-seeking journalists. When they have scientific evidence, it is generally based on epidemiological studies which cannot measure other factors (i.e. fat people gain weight, fat people drink diet soda…doesn’t mean diet soda causes weight gain). The rest of the time, it’s mostly hand-waving about toxicity. Yes things are toxic. But remember, 3,000 mg/kg of table salt will kill 50% of the people you feed it to.</tldr>
Diet Coke
Carbonated Water
Carbonated water erodes tooth enamel, though the effect is negligible. Intake of carbonated beverages has not been associated with increased bone fracture risk in observational studies. A 2004 article in the Journal of Nutrition found that fizzy waters with higher sodium levels reduced cholesterol levels and the risk of cardiovascular problems in postmenopausal women.
Caramel Color
Barring food alergy, no negative effects noted.
Aspartame
FDA has set its acceptable daily intake for aspartame at 50 mg/kg. For a 75 kg (165 lb) adult, it takes approximately 21 cans of diet soda daily to consume the 3,750 milligrams (0.132 oz) of aspartame that would surpass the FDA’s 50 milligrams per kilogram of body weight ADI of aspartame from diet soda alone. Even with ingestion of very high doses of aspartame (over 200 mg/kg), no aspartame is found in the blood due to the rapid breakdown. Clinical studies have shown no signs of neurotoxic effects, and studies of metabolism suggest it is not possible to ingest enough aspartic acid and glutamate through food and drink to levels that would be expected to be toxic. Reviews have found no association between aspartame and cancer. Review of the biochemistry of aspartame has found no evidence that the doses consumed would plausibly lead to neurotoxic effects. Claims that aspartame contributes to weight gain and obesity are not supported by the medical literature. Although there have also been claims that aspartame contributes to hunger or increased appetite, there have been few studies directly addressing the effect of aspartame on appetite. The data show no increased appetite with aspartame use, and this is an area of possible future research. Studies looking at caloric intake found that aspartame consumers consumed as many calories as or fewer calories than non-aspartame consumers, but not more. (See also: http://healthpsych.psy.vanderbilt.edu/2009/AspartameAppetite.htm, http://www.ncbi.nlm.nih.gov/pubmed/8451310/, http://www.ncbi.nlm.nih.gov/pubmed/19056571/, http://examine.com/faq/does-aspartame-increase-appetite.html). A double blind study subjected 55 overweight youth to 13 weeks of a 1,000 Kcal diet accompanied by daily capsules of aspartame or lactose placebo. Both groups lost weight, and the difference was not significant. Of the 4 studies from the meta-analysis that used beverages alone, the compensation was just 15% for the subsequent 24 hours; that is, the data suggest there is less compensation in beverages than foods, resulting in a more effective net reduction in calories when replacing sweetened beverages with Nonnutritive Sweeteners beverages.
Phosphoric Acid
The authors of this study conclude that the skeletal effects of carbonated beverage consumption are likely due primarily to milk displacement (another possible confounding factor may be an association between high soft drink consumption and sedentary lifestyle)
Potasium Benzoate
Potassium benzoate was recently described by the Food Commission, who campaign for ‘safer, healthier food in the UK’, as “mildly irritant to the skin, eyes and mucous membranes”.
Natural Flavors
Unknown, but likely a synthetic vanilla oil.
Citric Acid
Generally classified as healthful.
Caffeine
See http://en.wikipedia.org/wiki/Caffeine for well known positive and negative effects.
Diet Rite
Carbonated Water
See above.
Caramel Color
See above.
Phosphoric Acid
See above.
Sucralose
Results from over 100 animal and clinical studies in the FDA approval process unanimously indicated a lack of risk associated with sucralose intake. In a small scale study of 17 obese test subjects, sucralose was found to affect glycemic and insulin responses to an oral glucose load in obese people who do not normally consume NNS.
Citric Acid
See above.
Potasium Benzoate
See above.
Acesulfame Potasium
At 10x ADI, injected Acesulfame K may produce insulin secretion analogous to a similar amount of injected glucose.
Natural Flavors
See above.
Acacia Gum
Used to change the surface tension of the water used in the soda. Makes it more fizzy. Mostly organically inert.
Potasium Citrate
Buffering agent. Reduces ph impact of other acids in the drink. Used in some health treatments. No studied negative side effects.