The theory behind artificial sweeteners is simple: If you use them instead of sugar, you get the joy of sweet-tasting beverages and foods without the downer of extra calories, potential weight gain and related health issues.
In practice, it’s not so simple, as a review of the scientific evidence on non-nutritive sweeteners published Monday shows.
After looking at two types of scientific research, the authors conclude that there is no solid evidence that sweeteners like aspartame and sucralose help people manage their weight. And observational data suggest that the people who regularly consume these sweeteners are also more likely to develop future health problems, though those studies can’t say those problems are caused by the sweeteners.
The health effects of artificial sweeteners are important to study, because so many people use them. Another study published earlier this year found that a quarter of U.S. children and 41 percent of adults reported consuming them, most of them once per day. Even more people may be consuming them unwittingly in products such as granola bars or yogurt.
“We were really interested in the everyday person who is consuming these products not to lose weight, but because they think it’s the healthier choice, for many years on end,” says Meghan Azad, lead author of the review and a research scientist at the University of Manitoba. While more research needs to be done, from what we know now, “there is no clear benefit for weight loss, and there’s a potential association with increased weight gain, diabetes and other negative cardiovascular outcomes,” says Azad.
The review, published Monday in the Canadian Medical Association Journal, looked at 37 studies. Seven of them were randomized trials, covering about 1,000 people, and the rest were observational studies that tracked the health and habits of almost 406,000 people over time.
Both types of studies have their pluses and limitations. In the seven trials, people were randomly assigned to receive the sweetener or not, allowing researchers to compare the two groups and say with some confidence whether the substance caused a benefit or harm. But because of the cost and effort involved, randomized trials are typically shorter term and don’t include as many people.
They also may not reflect how people behave in the real world. Observational studies can track far more people for a much longer period, and they better reflect how people actually live. But the links they find between habits and health issues are associations, not direct evidence of cause and effect.
Most of the participants in the randomized trials were on a weight-loss program, and taken together, the results showed no significant impact of sweetener use on body mass index. The observational studies actually found a small increase in BMI associated with use of sweeteners, and a 14 percent higher chance of developing Type 2 diabetes for those who consumed the most artificial sweeteners compared to those who consumed the least (though there was a bias toward publishing studies that indicated a link, the authors noted). There was a 32 percent higher chance of cardiovascular events for the heaviest versus lightest users.
The Calorie Control Council, a trade group whose members include artificial sweetener manufacturers, notes that randomized trials have not confirmed those associations with diseases. It also says that obesity is complex, with many causes and requiring “personalized, multifactorial and multidisciplinary approaches using a variety of tools.”
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SOURCE: NPR – Katherine Hobson