May 19, 2017
The findings come from two studies presented here at the European Congress on Obesity (ECO) 2017 during a symposium sponsored by the International Sweeteners Association.
There has been some concern that using low-calorie sweetened drinks increases food intake by disrupting the responses to sweet taste and the "conditioned" satiety response, said Marc Fantino, MD, of CreaBio Rhone-Alpes research center, Lyon-Givors Hospital Center, France.
He presented a randomized controlled study showing that subjects who drank diet drinks (and who had previously never used them) did not eat more than those who drank water. And Charlotte A Hardman, PhD, of University of Liverpool, United Kingdom, presented preliminary data that indicate that diet drinks might help people to control sugar cravings.
The results overall add to a body of data that indicate that low-calorie sweetened beverages are an option for some people trying to reduce calorie intake and control their weight, say experts.
And despite many negative stories in the press indicating harm from such drinks, the scientific evidence suggests otherwise, they believe.
"All of the evidence for harm is from animal or epidemiological/correlation studies," said Richard Black, PhD, of Quadrant Consulting, West Harrison, New York. "When you do a tightly controlled interventional study [of diet drinks], the findings are neutral or beneficial," he told Medscape Medical News.
"Diet soft drinks do not lead to a healthier diet, but they can help you to minimize or avoid consumption of unhealthier products. That's a huge win," Dr Black added.
And John L Sievenpiper, MD, PhD, of St Michael's Hospital, Toronto, Ontario, a medical biochemist who has conducted a number of studies in this area, said: "Our preferred gold standard [to drink] is water. That's what we advocate. But there has to be some recognition that that's not going to work for everyone, it's not going to fit with their values and preferences."
Meanwhile Paolo Sbraccia, MD, PhD, an internal medicine physician who treats many patients with obesity and diabetes but who has not been involved in any trials of diet beverages, told Medscape Medical News that he thinks they can be most useful for the younger generation.
"Diet drinks might have a role in children. But I doubt that in [obese] adults, they will help much," he observed. Nevertheless, he doesn't harbor any concerns about their safety: "Overall, I'm not concerned about harm."
Diet Drinks a Viable Option
Dr Fantino reported his trial in which 80 women and 86 men who hadn't previously consumed diet drinks were randomized to low-calorie sweetened beverages or water and then were allowed to eat as much as they wanted.
"The daily intake of beverage sweetened with low-calorie sweeteners (660 mL/day) for 4 weeks by healthy normal-weight men and women who were not regular consumers of intense sweeteners did not promote selection and intake of more sweet foods" nor increase the intake of calories, he reported.
The results are in line with the conclusions from a study published by Rogers et al last year (Int J Obes [Lond]. 2016;40:381-394), said Dr Fantino.
This systematic review concluded that "the preponderance of evidence from all human randomized controlled trials indicates that low-energy-sweetener consumption does not increase energy intake or body weight, whether compared with caloric or noncaloric (for example, water) control conditions."
These data should reassure doctors and consumers, said Dr Hardman, who is a psychologist and who noted that negative press about possible harms of diet drinks has had an impact.
"If the message can become beneficial, it takes something away from the negative stories," she observed.
She cautions, however, "Diet drinks can aid weight loss, but they are not a solution for everyone. For those who don't like sweet-tasting foods, low-calorie sweetened drinks are not going to be useful. It's all about individual preferences."
Dr Sievenpiper agrees. He told Medscape Medical News: "Diet drinks are a viable option, so let's not take them off the table."
Dr Black said: "Some people use [a diet drink] as a tool to satisfy the cravings. It will not lead to weight loss by itself, but it can be used to support your weight-loss efforts."
However, all of the experts in Porto said that while they would be confident their comments apply when talking about diet beverages, the issue becomes much more complex when talking about solid foods containing sweeteners, so they would not extrapolate any of their conclusions to such products.
What About Sweeteners' Effects on the Gut Microbiome?
Asked also for his opinion on a Nature paper a few years ago that suggested artificial sweeteners may unfavorably alter the gut microbiome, leading to insulin resistance (Nature. 2014;514:181-186), Dr Sievenpiper said: "This paper has a lot of issues and is often misrepresented. Suez et al looked at sucralose, aspartame, and saccharin but investigated only saccharin ("as a prototypical artificial sweetener") in humans at the max FDA acceptable daily intake (5 mg/kg body weight/day which is equivalent to 45 table-top sweeteners)."
In addition, the research was not controlled (ie, there was no group receiving placebo with which to compare the effect of saccharin); rather, it was simply a "before-after" study.
And "to show an effect, they also had to divide the very small number of subjects (n=7) into responders (four of seven) and nonresponders (three of seven), showing an effect only in the 'responders.' This approach is highly dubious, especially given the already-weak design."
The conclusions are therefore "extremely speculative," he said, and extrapolating these to all low-calorie sweeteners "is a further massive leap of inference." These sweeteners are a "heterogeneous group of compounds that are handled differently by the body in terms of their absorption, metabolism, distribution, and excretion."
This study "clearly needs replication in a randomized controlled trial using "real-world" (not maximum acceptable daily intake) doses and sweeteners that are actually used in beverages (such as aspartame, sucralose, and acesulfame K)," he noted.
Indeed, Dr Sievenpiper's group has just been funded by the Canadian Institutes of Health Research to conduct just such a trial, he concluded.
Dr Fantino and Dr Hardman consult for the International Sweeteners Association. Dr Sievenpiper reports speaker fees or honoraria from PepsiCo, Dr Pepper Snapple Group, and the International Sweeteners Association and ad hoc consulting for Tate and Lyle and research support from the Calorie Control Council. Dr Black and Dr Sbraccia report no conflicts relating to the beverage or sweetener industry.