Yes, I am going to keep riding this one. Aaron Carroll (already my favorite physician-cum-blogger) takes a nice, thorough look at the risks of added sugar versus added artificial sweeteners in the Upshot. Given that I’m sharing it, you will not be surprised at to its conclusions:
A 1998 randomized controlled trial could detect no neuropsychologic, neurophysiologic or behavioral effects caused by aspartame. Even a dose at 10 times the normal consumption had no effect on children with attention deficit disorder. A safety review from 2007, published in Critical Reviews in Toxicology, found that aspartame had been studied extensively and that the evidence showed that it was safe. [emphases mine]
It is true that people with phenylketonuria, a rare genetic disorder, need to limit their consumption of aspartame, since phenylalanine is one of its components. But for most people, aspartame isn’t a concern, even outside of cancer. It’s also true that some of the sugar alcohol sweeteners, like sorbitol or mannitol, can have a laxative effect or cause bloating when eaten in large amounts by some people. In normal use by most people, though, all of the approved artificial sweeteners are safe.
When I argue these facts with my friends, they want to know if I put my money where my mouth is. I do. My wife and I limit our children’s consumption of soda to around four to five times a week. When we let them have soda, it’s almost always caffeine-free, because we want them to sleep. It’s also almost always sugar-free. There’s a potential, and probably real, harm from consuming added sugars; there are most likely none from artificial sweeteners.
In fairness, I’m not actually trying to convert anybody to diet soda. Drink water! But I get so tired of people who are convinced about how bad diet soda is for you despite the lack of any strong evidence.
So, I was originally going to end the post there, but a friend shared on FB, and a reply came back with, “but aspartame is bad for your gut bacteria!” Well, you know me, that had to be investigated. Well, on closer inspection, it appears it is only saccharin that is bad for your gut bacteria. If you are a mouse. Of course, mouse models are important and I very much believe we should pay attention to how various foods and additives affect our microbiome, but even with this study, it’s hard to make the case against aspartame.
Am I going to change the minds of any diet soda skeptics? As Drum points out in his take… no. Just ask yourself if you are motivated reasoning your way out of this one:
Anyway, that’s what science says. Unfortunately, science also says that presenting facts to people almost never changes their minds. In fact, it can do just the opposite as people respond defensively to the notion that they’ve been wrong for a long time. So I suppose no one reading this is actually going to switch to diet sodas. Instead they’ll cherry-pick studies that support their previous point of view. Or claim that all the studies exonerating artificial sweeteners are funded by big business and not to be trusted. Or perhaps make an outré claim about how aspartame interacts with gluten and animal fat to produce….something or other.
Of course, as somebody who drinks liters of diet soda per day, maybe this is all motivated reasoning on my part. Maybe, but I still think its mostly just science.