Don't Believe the Headlines: Artificial Sweeteners Not Conclusively Better Than Sugar

A New York Times article proclaimed on Monday that, based on scientific evidence, artificial sweeteners are safer to consume than sugar. But experts say only part of the story is being told here. (Photo: Getty Images)

You’ve heard it repeatedly: Sugar is bad for you. But then you’ve also heard that artificially sweeteners aren’t great either.

So … what are we supposed to think?

A pediatrician is attempting to answer that question in an article published Monday in The New York Times. In it, Dr. Aaron E. Carroll, a professor of pediatrics at Indiana University, presents compelling evidence on why, when he does allow his kids to have soda, he gives them the sugar-free bubbly stuff vs. traditional versions made with sugar. His reasoning: Artificial sugar is better for you than the real stuff.

“The available evidence points to the fact that there appears to be a correlation between sugar consumption and health problems; none can be detected with artificial sweeteners,” Carroll boldly states in the article.

Among other research, Carroll cites a 2004 review article published in The Annals of Oncologythat points out that, of the more than 50 studies that have been published that investigated the side effects of saccharin — a controversial sugar substitute found in many diet sodas — on rats, 20 didn’t look at the effect on the rats’ offspring. “In only one of those studies did huge amounts of saccharin produce cancer, and it was in a type of rat that is frequently infected with a bladder parasite that would leave it susceptible to saccharin-induced bladder cancer,” he writes. However, studies that looked at the impact on saccharin on rats and their offspring found that bladder cancer was significantly more common in second-generation rats. That prompted action by several countries.

Carroll argues that some rats are just more prone to bladder cancer, and that the link has never been found in humans. And that’s why he says he has no problem giving his kids four or five sugar-free sodas a week.

Carroll makes a strong argument, but other experts say he has left out some important facts.

“I’m blown away by this,” Dr. Robert Lustig, professor of pediatrics in the Division of Endocrinology at University of California, San Francisco, and president of the Institute for Responsible Nutrition, tells Yahoo Health. “This is not okay.”

Behavioral neuroscientist Susan E. Swithers, a professor of psychological sciences at Purdue University who has studied the effect of artificial sweeteners on the body, doesn’t agree with Carroll either. She says that research associates artificial sweeteners with increased risks of developing Type 2 diabetes, cardiovascular disease, high blood pressure, and stroke.

“I would argue artificial sweeteners are not harmless, but may instead contribute to produce the very outcomes people are trying to avoid,” she tells Yahoo Health.

While Lustig says research does not definitively say that artificial sweeteners are bad for us, he also says there is compelling evidence that they’re not good for us, either.

He says there isn’t a lot of long-term data on the health risks to humans of ingesting artificial sweeteners. “The FDA isn’t asking for it, and the NIH won’t pay for it,” says Lustig. “We just don’t have the data … so how is Dr. Carroll so sure that he’s right?”

The short-term data doesn’t exactly rule in favor of artificial sweeteners, though. The fake stuff can interfere with the way our body reacts to a sweet taste, says Swithers. She notes that our bodies anticipate the arrival of sugar and energy after we have a sweet taste, and hormones are released in anticipation of sugar.

But artificial sweeteners break the rules; the mouth gets the sweet taste but the body doesn’t get the sugar it’s expecting — yet the body still produces insulin to absorb it. When the insulin doesn’t find sugar, it essentially tells the brain that you’re hungry. As a result, Lustig says, you can end up overeating other foods.

Recent research published in the journal Diabetes Careconducted on obese people found that, when they were given the artificial sweetener sucralose (found in Splenda) to drink before taking a glucose challenge test, their blood sugar peaked at a higher level than when they drank only water before the test. Their insulin levels also rose by about 20 percent, which researchers say could lead to weight gain and type 2 diabetes if the response happens repeatedly.

Artificial sweeteners have also been shown to alter the bacteria in our guts. A rat study published last year in the journal Nature found that the sweetener aspartame promoted glucose intolerance in rats, regardless of what they ate. (Glucose intolerance is linked to Type 2 diabetes.)

While Lustig notes that we don’t have similar data from humans, he says it would be a “big issue” if the same outcome can be proven in people: “If you screw up your intestinal microbiome, you’re going to get sick.”

But, before you freak out, know this: Dr. David Katz, director of the Yale University Prevention Research Center, tells Yahoo Health it’s probably OK to consume artificial sweeteners on occasion. “I don’t think any one dietary indulgence makes or breaks a diet,” he says.

However, he points out that taste buds are adaptable, and they learn to love the foods you give them — including wholesome, nutritious grub. With that in mind, he says, there’s really no reason to have a soda (diet or otherwise) in the first place.

So, are artificial sweeteners good for you? Definitely not. Are they better for you than sugar? Despite what you may have read, the jury’s still out on that one.