The study he links is by Gallus and colleagues (2006), who actually found that artificial sweeteners were NOT linked to any of those cancers. There was a positive association for total artificial sweetener consumption only with laryngeal cancer, but an inverse with breast and ovarian cancer. So do artificial sweeteners prevent cancer too? No – the authors concluded:
“In conclusion, therefore, this study provides no evidence that saccharin or other sweeteners (mainly aspartame) increase the risk of cancer at several common sites in humans.”
As for diabetes, the research is mixed (negative: Schulze et al. (2004), de Koning et al. (2011) ; positive: Fagherazzi et al. (2013), Nettleton et al. (2009), Dhingra et al. (2007). and Dr. Oz doesn’t acknowledge this. There is limited research on how artificial sweeteners could increase diabetes risk. I have written in detail on several studies examining associations between artificial sweeteners and metabolic syndrome which is closely associated with diabetes. These are also mixed but the better study designs seem to show no risk. It is very difficult to accurately tease out a single dietary factor because different datasets often have different lifestyle and dietary variables. Almost all of the papers I have read give a note of caution in the discussion when interpreting because of the potential of confounding dietary or lifestyle variables, and note a need for randomized controlled trials and mechanistic studies.
Dr. Oz also writes that “many of us may not realize that common artificial sweeteners like aspartame (found in NutraSweet or Equal), saccharin (found in Sweet’N Low) or sucralose (found in Splenda) can actually cause weight gain.”
This is not an accurate characterization of the current evidence. It is known that there is generally some compensation in calories from other sources when sugars are replaced with artificial sweeteners, but it is likely incomplete (resulting in a small negative caloric balance). The American Heart Association and American Diabetes Association recently published a nice review on this. They write:
“The evidence reviewed suggests that when used judiciously, NNS [nonnutritive sweeteners] could facilitate reductions in added sugars intake, thereby resulting in decreased total energy and weight loss/weight control, and promoting beneficial effects on related metabolic parameters.”
However, they note that evidence is currently insufficient to be confident that substituting artificial sweeteners for sugar would result in long term energy deficits and weight change.
In addition, Piernas et al. (2013) recently published data that suggests artificial sweeteners do not increase intake of total or added sugar, and in fact both groups (those who drank artificially sweetened drinks and those who drank water similarly reduced total calories over the 6 month period.
It is mind-boggling that Dr. Oz is considered a credible nutrition resource by many, and relatively speaking to the other nonsense he promotes, this is one of his least objectionable acts.
(hat tip David Despain)