Some recent studies question whether diet sodas sweetened with artificial sweeteners like NutraSweet and Splenda actually help keep off the weight.
This month’s Journal of the American Geriatrics Society published research from a long-term study of hundreds of people 65 years old and up in San Antonio, some who drank diet soft drinks regularly. The study found that the waists of diet soda drinkers grew three times as much as those who avoided soft drinks sweetened with artificial sweeteners.
“What these are telling us is that obesity is far more complex than we have ever thought,” said Leanne Redman, a scientist at the Pennington Biomedical Research Center who studies weight gain and obesity in women.
Doctors involved with the study concluded that “increasing diet soda intake was associated with escalating abdominal obesity,” which can lead to higher risk of heart disease, stroke and diabetes. While the study does not directly prove that diet drinks cause weight gain, researchers have more questions. Artificial sweeteners’ effect on the body are just not that well understood, Redman said.
Researchers and consumers have long been suspicious of artificial sweeteners such as aspartame, used to create NutraSweet and Equal, and saccharin, an ingredient in Sweet’N Low. Regulators have not been shown proof that they are any more dangerous than sugar, Redman said.
“You can obtain a sweetened food without having the calories of sugar,” she said. “They were believed to be a more healthful choice. Believe it or not, they are still viewed that way for the most part.”
For people with glucose intolerance, including diabetics, artificial sweeteners are the best recommendation for sweet foods and drinks.
“They don’t affect things like blood sugar levels, which is what diabetics and people with insulin resistance need to be paying close attention to,” Redman said. “Whether you think they are healthy or not, they still have that benefit.”
A glaring question raised by the San Antonio study is, what else did the participants eat? Did the diet soda drinkers eat more fast food? Or did they grab their no-calorie sodas at a convenience store along with a bag of potato chips?
Diet sodas are still recommended as healthier alternatives than the empty calories of sugary Cokes and Dr Peppers. “Now by doing that, we’re taking people who are soda drinkers and providing them with a more healthful option,” Redman said, “but we’re not talking to them about the things they consume at the same time they are drinking the soda.”
Redman and other scientists also question what artificial sweeteners do the good bacteria in the human gut. Research published in the journal Nature last fall showed that mice fed artificial sweeteners in their water developed a glucose intolerance, a condition similar to that of Type 2 diabetics.
Researchers decided the sweeteners affected the gut bacteria when they transplanted fecal matter from the glucose-intolerant mice to mice raised in a germ-free environment. Those germ-free mice developed the same condition as those fed the sweeteners.
“I think there is something to this, that sweeteners are potentially affecting what’s going on in the gut,” Redman said.
While artificial sweeteners have been understudied, researchers have only begun to understand how the gut microbiome — the millions of bacteria in our gastrointestinal tract — functions in the past decade.
“The gut microbiome is so intriguing,” Redman said. “As scientists we are just starting to scratch the surface.”
Redman said she still uses artificial sweeteners occasionally and gives food products containing them to her children, but she doesn’t drink soda. She wonders why modern eaters desire sweetened drinks on a regular basis. They don’t slake thirst better than water, she said.
“We’re just drinking to satisfy something else,” she said.