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Our episode on Organic food was a hit, but lots of you had questions in the comments asking about the safety of artificial sweeteners. We live to serve, so this week's episode is about the research in that area. These chemicals get a bad rap, but you might be surprised by what you learn by watching. Send your hate tweets to Aaron. He's used to them.

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Here are references for all the stuff I talk about:

John Green -- Executive Producer
Stan Muller -- Director, Producer
Aaron Carroll -- Writer
Mark Olsen - Graphics


I've been getting a lot of comments and questions about artificial sweeteners. You wanna know if they're safe, we live to serve. Welcome to Healthcare Triage.

(Intro music plays)

People are justifiably suspicious of chemicals. I'm fine with that. But sometimes that suspicion goes to far. Sometimes chemicals, including drugs do some good. There's a definite benefit to artificial sweeteners. Have you seen our collective waistline recently? The important question is are there harms that outweigh the benefit?

 Saccharin (0:32

We have a ton of data on whether artificial sweeteners are harmful. Not all artificial sweeteners are the same. Saccharin is one of the oldest, and made from coal tar according to Mental Floss. There have been more than 50 studies written about the effect of saccharin on rats. About 20 of them were done in rats consuming saccharin for at least one and a half years. 19 of these studies found nothing. One study found an increase rate of bladder cancer, but it was in a type of rat that gets easily infected with a bladder parasite that can leave it more susceptible to cancer.

 Scientists then moved on to see if giving saccharin to two generations of rats would do anything. They fed rats and then their rat children lots and lots of saccharin. They found that male rats in the second generation got more bladder cancer. Because of this some countries banned saccharin and others, like the United States, started labeling products with warnings. There was one problem. The link between saccharin and cancer couldn't be found in humans. Ironically, later work found that often, cancer induced in rats doesn't equal cancer in humans. For instance, if you give rats vitamin C in the same dose as saccharin in similar studies, that causes bladder cancer in rats too, yet no one attempts to ban vitamin C. There's no real evidence, even in the animal models, that saccharin is dangerous.  

 Cyclamate (1:48)                  

Cyclamate was approved by the FDA for use in the United States in 1950. Almost 20 years later, a landmark study found that cyclamate increased the rate of, wait for it, bladder cancer in rats. This led to it being banned in a number of countries. Later the ban was lifted pretty much everywhere except for the US. Always with the rats and their cancerous bladders. But in one of those studies you can't believe they actually did, some scientists fed thirty-seven monkeys either no cyclamate, 100mg per kilogram of cyclamate, or 500 mg of cyclamate everyday for twenty-four years.

By the way, 500 mg per kilogram is like drinking thirty cans of diet soda a day for twenty-four years.

At the end of the study they killed the remaining monkeys and autopsied them. Three animals in the cyclamate receiving group had cancers,  but they were different types of cancer in different parts of the body and they were common cancers in monkeys.

Their conclusion was that there was no apparent risk in consuming that much cyclamate. Did that change our policy? Of course not.

 Aspartame (02:50)

This brings us to aspartame. Today, this seems to be the sweetener of choice when discussing harms. Approved for use in 1981, it took until 1996 for panic to set in. In that year a paper was published that got a lot of attention. It discussed the fact that there had been a recent increase in the incidents of brain tumors and questioned whether this could be linked to aspartame. As usually happens with these kinds of things, the media had a field day.

But here's the thing, further investigations with national cancer institute statistics showed that brain cancer began in 1973; eight years before aspartame was introduced. Also most of the increases in people with brain tumors were seen in people over seventy, who are not huge consumers of diet soda. As with vaccines and autism, once the myth is out there, it's really hard to beat it down.

A double- blinded, randomized, controlled trial of self- reported "aspartame sensitive people" showed that aspartame didn't cause headaches. A similar study showed that it didn't affect memory, behavior, mood, or even EEG changes. Another study, published in 2006, followed more than 285,000 men and almost 190,000 women and couldn't detect any relationship between aspartame and brain or blood cancer.

And don't bring up methanol and artificially sweetened beverages either. Analyses show that there is more methanol in a glass of tomato juice or in fruits and vegetables than there is in diet soda. Some people find diet beverages distasteful for other reasons.

 Other Reasons (4:13)

A few studies have shown that drinking artificially sweetened beverages doesn't promote weight loss, or even promotes weight gain. More often than not, this is because people end up over-compensating for calorie savings they think they're getting for switching beverages. Think of the person who orders dessert as a reward for having diet soda. But in those cases, it's not the diet beverage that caused weight gain; it's the dieter's behavior. You can even find people who postulate that artificially sweetened beverages trick the brain into wanting more calories, but there's really no proof of that.

Finally, some will claim that diet drinks will cause the brain to release insulin, which can change your metabolism and make you hungry. That's a bit hard to swallow. That's like saying if you eat sugared, dense food that tasted terrible, it would trick your brain into not releasing insulin. That doesn't happen, of course. It's the pancreas that releases insulin, anyway, not the brain.

 Bottom Line (05:00)

The bottom line is that artificially sweetened beverages are safe. That doesn't mean you should tons of them. My wife and I limit our kids consumption's of soda to caffeine-free, diet types, but we don't let our children drink them everyday. We stress moderation in everything, including such drinks. A study published just a short while ago in JAMA Internal Medicine found that the added sugar from drinking just one extra 20 ounce Mountain Dew a day is associated with a significantly increased risk of cardiovascular disease.

We shouldn't make the perfect the enemy of the good. Given a choice between a sugared soda and a sugar free soda, I'd chose the latter every time. There's an abundance of evidence that an overconsumption of sugar is contributing to health problems. There's a lack of evidence that artificial sweeteners are doing the same thing.