Researchers Have Bad News About the Health Benefits of Non-Sugar Sweeteners

With the rising popularity of low-carb diets, sugar substitutes are experiencing a resurgence, but it turns out their advantage may be overstated. Sure, non-sugar sweeteners — including artificial sweeteners like aspartame or sucralose and natural, non-caloric sweeteners like stevia — might seem like healthier alternatives to sugar since they ostensibly deliver fewer carbohydrates and calories, but there’s no comprehensive research to help consumers and healthcare professionals make well-informed choices about these substances. That picture is about to get a bit clearer, though. To illuminate how non-sugar sweeteners actually stack up, the World Health Organization commissioned a systematic review of all the available research on sugar alternatives, and the results came out on Wednesday.

In a paper published in The BMJ, a team of researchers outlined what the available evidence shows and — perhaps just as importantly — does not show about non-sugar sweeteners. To put it simply, the team found there isn’t good evidence showing that non-sugar sweeteners are actually good for you. Corresponding author Joerg Meerpohl, M.D., director of the Institute for Evidence in Medicine at the University of Freiburg in Germany, says much of the available research on the topic is inconsistent in terms of how the studies were conducted, what effects they were measuring, and how long the studies lasted.

“Despite the fact that [non-sugar sweeteners] are available for many many years, and widely used and promoted, overall there is currently only limited data of mostly low or very low certainty available to assess health benefits and potential harms of [non-sugar sweetener] use,” he tells Inverse. “Unfortunately, we need more and better research on this topic.”

To assess the state of evidence on non-sugar sweeteners, Meerpohl and his team combed through 56 different studies. Here’s what they found in the current state of evidence on how non-sugar sweeteners affect various aspects of human health:

Body Weight

Out of the randomized controlled trials — the gold standard of evidence in medical research — examining the relationship between non-sugar sweeteners and body weight in adults, there was no significant effect on body weight in subjects who consumed non-sugar sweeteners as opposed to sugar or a placebo. A few other studies did show small amounts of weight loss, but not in people who were actually trying to lose weight.

Diabetes or Glycemic Control

Two randomized controlled trials showed slightly lower blood glucose levels in people who used non-sugar sweeteners versus sugar, but these studies included a relatively small number of people, so they aren’t considered strong evidence. Other studies, though, showed no improvement.

Eating Behavior

Studies examining whether non-sugar sweeteners helped people consume fewer calories showed mixed results. One large study did show significantly reduced caloric intakes, while others did not. In obese participants, those consuming non-sugar sweeteners did eat less sugar — a fairly obvious conclusion. But another study showed no difference in sugar intake.

Cancer

The cancer risk in people who consumed non-sugar sweeteners did not seem to be much different than those who didn’t, though the researchers note that these studies showed a very low certainty of evidence. In other words, just because the studies found no strong effect, that doesn’t mean it’s not there.

Blood Pressure

Again, this category was a mixed bag. Some studies showed that people who used non-sugar sweeteners had lower blood pressure, whereas other studies showed no significant difference between them and sugar eaters.

So What Does This All Mean?

All in all, this paper shows that the evidence for or against non-sugar sweeteners is inconclusive. Some studies show that replacing sugar with non-sugar sweeteners can improve certain aspects of your health, while other studies suggest that it doesn’t make a major difference. This conclusion comes down to the study designs, in a lot of cases. Some of the researchers didn’t follow enough people, some of them didn’t follow people for long enough, and some of them simply didn’t collect data very well.

Meerpohl and his colleagues note that they initially identified nearly 14,000 studies on non-sugar sweeteners, but only ended up including 56 once they had screened them for quality and relevance. And even among the studies that remained, the evidence that remained generally wasn’t of very high quality.

“I would say that there is no convincing evidence of clear health benefits in the general population,” Meerpohl says. “There might be a small benefit on weight, but we don’t have high-quality data with long-term follow-up that definitely confirm this effect.”

Right, but What Should I Do?

For anyone who’s trying to decide whether to switch from sugar to non-sugar sweeteners in order to lose weight, Meerpohl advises avoiding the whole mess with a simple piece of advice: Just steer clear of sweets altogether.

“Water, and non-/less-sweetened foods,” he counsels. “In other words, there is no need to either add additional sugar or sweeteners in most instances.”