The FDA recently required statin drugs to carry a warning stat- ing they may increase the risk of type 2 diabetes and developing impaired memory. A study that followed more than 2,500 adults found that drinking diet sodas daily may increase the risks for heart attack and stroke and other vascular events by 43 percent, but no such threat exists with regular soft drinks or with less frequent consumption of diet soda. The results were published online in the Journal of General Internal Medicine on January 30, 2012. Media reports may lead some to switch to regular sodas and stop their statins even though these data were not from well-designed studies. There is no known plausible mechanism by which diet sodas or non-caloric sweeteners might cause more heart attacks or strokes nor is there any reason to believe statins might lead to diabetes or dementia. Science tells us correlation alone does not prove causation. The observational data that recently linked statin use with an increased risk of developing type 2 diabetes and memory loss and led the FDA to require a warning label on all statins even though it may prove to be of no real concern.Observational studies are notoriously unreliable because without randomization there may well be real differences between those who end up being prescribed statins or choosing to drink diet colas and others the same age. For example, it seems likely that those being put on statins by their MDs would have been more likely to have had more CVD risk factors than other patients not prescribed cholesterol-lowering statins. Insulin resistance (IR) is known to be associated with more CVD risk factors such as an increased waist, and higher blood pressure, blood triglyceride and glucose levels and/or a lower HDL-Cholesterol level. And IR is also a known risk factor for the development of type 2 diabetes. Therefore, it is more than likely that patients prescribed statins were done so in part because they were diagnosed with the metabolic syndrome were deemed by their MDs to be at increased CVD. However, they were also likely to be significantly more likely to end up with type 2 diabetes than other people whose MDs did not think their risk of CVD was high enough to justify the use of statins.Are people who chose to drink diet sodas the same as those who chose to drink regular sodas? Probably not. Common sense tells us that people electing to drink diet sodas are more likely to be struggling to keep their weight down than those who indulge in regular colas. If so diet soda intake may just be a marker for people who are more likely to be more prone to gain weight in the future. We already know people who gain weight are more likely to end up with more CVD than those who do not gain weight. So diet soda consumption may just a marker for (rather than a cause of) weight gain or increased CVD risk. Again those who gain weight are more likely to end up with insulin resistance, the metabolic syndrome, and more heart attacks and strokes.Of course, diet sodas provide no nutritional value and especially consumed in large amounts might cause some health concerns. Diet colas can be high in phosphoric acid and artificial caramel coloring. This artificial caramel coloring used in most colas is made with ammonia, sulfites, and sugar and is not the same as real caramel made from browning sugar. There is data in animals that at least two of “caramel coloring” components (methylimidazoles) can promote cancer in animals. The occasional diet coke may provide little cancer risk but it may be that a steady diet of several diet (or regular) cokes daily for decades could pose a modest risk for human cancer too. And large amounts of phosphoric acid may be bad for bone metabolism and contribute to hyperparathyroidism and osteoporosis.Bottom Line: So people interested in a healthier calorie-free beverage should perhaps switch from diet sodas to iced tea sweetened with Splenda. Tea drinking is known to reduce the risk of CVD and perhaps also the risk of type 2 diabetes and some types of cancer. If one must do a diet soda then they should be encouraged to choose one that has little or no phosphoric acid and does not have other potentially questionable additives like the artificial “caramel coloring” used in most colas and root beers.By James J. Kenney, PhD, FACN.For more information on diet and heart disease and diet and type 2 diabetes, visit foodandhealth.com and click on CPE at the top in the blue bar. You may read Dr. Kenney’s research on many topics for free. CPE points are available to members for a discount.