Researchers say consumption of artificial sweeteners such as saccharin, sucralose and aspartame led to increased risk of glucose intolerance, a condition linked to diabetes. Sweet ‘N Low contains saccharin. Equal original contains aspartame. Splenda contains sucralose. (iStockPhoto) 
 
 Artificial sweeteners might be triggering higher blood-sugar levels in some people and contributing to the problems they were designed to combat, such as diabetes and obesity, according to new findings published Wednesday in the journal Nature. 
 
 Although the precise reasons behind the blood-sugar changes remain uncertain, researchers suspect that artificial sweeteners could be disrupting the microbiome, a vast and enigmatic ecosystem of bacteria in our guts. 
 
 In a series of experiments, researchers found that several of the most widely used types of non-calorie sweeteners in food and drinks — saccharin, sucra­lose and aspartame — caused mice to experience increased risk of glucose intolerance, a condition that can lead to diabetes. 
 
 “We are talking about very dramatic increases,” said one of the study’s co-authors, Eran Segal, a computational biologist at the Weizmann Institute of Science in Israel. 
 
 The same scientists also monitored what happened to seven human volunteers who did not typically use artificial sweeteners but were given regular doses of saccharin over the course of a week. Four developed significant glucose intolerance. Separately, the researchers analyzed nearly 400 people and found that the gut bacteria of those who used artificial sweeteners were noticeably different from people who did not. 
 
 View Graphic Using some artificial sweeteners might increase blood sugar 
 
 “This huge and poorly understood microbial world, which resides in each and every one of us starting from birth, has been shown to play a fundamental role in many aspects of our physiology, as well as in [our] susceptibility to common human diseases,” said Eran Elinav, another of the study’s co-authors and an immunologist at the Weizmann Institute. 
 
 Wednesday’s findings add an intriguing new dimension to the long-running, contentious debate over the potential health benefits and risks of artificial sweeteners, which are among the most common food additives and are consumed by hundreds of millions of people around the globe. 
 
 While some past studies have found that the products pose no health risks and effectively help people cut calories and sugar intake, other research has suggested that certain artificial sweeteners might actually contribute to obesity and other problems, including cancer. 
 
 Segal and Elinav insisted that their findings are preliminary and shouldn’t be taken as a recommendation on whether people should reconsider using artificial sweeteners. 
 
 “We do not view that as our role,” Segal said. “Rather, as scientists, we simply point to the immense body of experiments that we carried out in both humans and in mice. . . . This study and these results should prompt additional debates and study into what is currently a massive use of artificial sweeteners.” 
 
 Elinav added: “This issue is far from being resolved.” 
 
 Lisa Lefferts, a senior scientist at the nonprofit Center for Science in the Public Interest, agreed. She praised the rigor behind Wednesday’s study and the “very provocative results” it produced, but she said the findings don’t negate past studies showing that people are more likely to gain weight when drinking sugar-sweetened beverages than when using artificial sweeteners. 
 
 Rather, she said, the various ways the scientists measured the effect of saccharin on the gut microbiota suggest a definite, if unresolved, link. 
 
 “We have more confidence now that there really is something going on, at least in animals,” Lefferts said. “What does that mean over the long term for the population? We still don’t have that answer.” 
 
 In addition, Lefferts and the study’s authors said people shouldn’t see the findings as a suggestion that sugar-sweetened drinks are somehow preferable to artificial sweeteners. 
 
 “We must stress, by no means are we saying that sugary drinks are healthy and that sugary drinks should be brought back as a healthy part of our nutrition,” Elinav said 
 
 The Food and Drug Administration has approved six different types of sugar substitutes, or “high-intensity” sweeteners, with the most recent coming this year. The three types included in Wednesday’s study involving mice — saccharin, sucralose and aspartame — are more commonly known by the popular brand names Sweet n’ Low, Splenda and Equal, respectively. However, the researchers relied primarily on saccharin in their mouse and human experiments. 
 
 Perhaps no sweetener has proven more controversial than saccharin, which was discovered not long after the end of the Civil War. In 1977, the FDA tried to ban saccharin because of safety concerns after studies showing that rats had developed bladder cancer after receiving high doses of the chemical sweetener. 
 
 Congress blocked that effort, instead passing legislation that required a warning label on products containing saccharin. In 2001, federal legislation removed the requirement for a warning label altogether. 
 
 The American Medical Association and the American Diabetes Association have cautiously backed the use of non-caloric sugar substitutes as a way to fight obesity and diabetes, saying that the products can be part of a healthy diet as long as the calories saved aren’t replaced by consuming more food over the course of a day. ||||| When artificial sweeteners are in the news, it’s rarely positive. In the last few years, sweeteners have been linked to everything from Type 2 diabetes to cardiovascular disease, high blood pressure, and stroke. Still, products like Splenda and Sweet‘N Low remain a cornerstone of many a weight-loss strategy, mostly because doctors don’t quite understand how sweeteners contribute to disease. That may soon change, however, as results from a study, published today in Nature, point to a possible mechanism behind these adverse health effects. 
 
 "Our results suggest that in a subset of individuals, artificial sweeteners may affect the composition and function of the gut microbiome" in a way that would lead to high blood-sugar levels, said Eran Elinav, an immunologist at the Weizmann Institute of Health in Israel and a co-author of the study, during a press conference yesterday. This, the researchers say, is bad for human health because when sugar levels are high in the blood, the body can’t break it down, so it ends up being stored as fat. 
 
 High blood sugar ends up being stored as fat. 
 
 To reach these conclusions, Elinav and his team first tested the effect of three common artificial sweeteners — aspartame, sucralose, saccharin — on rodents. They found that each of the sweeteners induced a change in blood sugar levels that surpassed that of the mice who consumed actual sugar. And later tests involving the main sweetening agent in Sweet‘N Low, saccharin, yielded similar results in both lean and obese mice. 
 
 But mammals don’t actually digest artificial sweeteners — that’s why they’re "calorie-free" — so the reasons why these mice were experiencing blood-glucose alterations was still mysterious, Elinav said. Still, the researchers had an idea: maybe the bacteria that lived in the guts of the mice were interacting with the sweeteners. 
 
 So the researchers performed several experiments to test their idea. In one, they gave antibiotics to mice who had been fed sweeteners regularly. Antibiotics kill gut bacteria, and when these mice had their microbial guests cleaned out, their blood sugar levels went back to normal. In another experiment, the scientists transplanted feces — a rich source of gut microbes — from sweetener-fed mice into rodents that had never consumed artificial sweeteners. The procedure caused the recipient mice to experience oddly high blood glucose, like the mice in the sweetener group. Finally, Elinav and his colleagues used genetic analysis to reveal that alterations in the composition of microbial colonies were also accompanied by changes in bacterial function — changes that could very well explain why the mice were experiencing such high blood sugar. 
 
 Findings in mice aren't nearly as convincing as findings in people 
 
 But findings in mice aren’t nearly as convincing as findings in people, so the researchers set out to investigate human sweetener consumption. In the first experiment, the researchers analyzed the blood-sugar levels and gut bacteria colonies of 381 participants. And, as expected, Elinav and his colleagues found that people who consumed sweeteners in large quantities also showed disturbances in several metabolic parameters — including increased weight — as well as distinct microbial changes in their guts. 
 
 The results from the second, much smaller human experiment might actually be the most illuminating. 
 
 "We followed for a single week a group of seven human volunteers who do not consume sweeteners as part of their normal diet," Elinav said. During that period, the researchers gave them a single dose of saccharin, and monitored their vitals. After just four days, half the participants showed microbial alterations and increases in blood sugar levels, he explained, "while the other subset had no meaningful effect immediately following the consumption of sweeteners." 
 
 In other words: some people are more susceptible to the effects of artificial sweetener than others. 
 
 A causal link 
 
 The handful of studies suggest that consuming non-caloric artificial sweeteners boosts the risk glucose intolerance in both humans and mice, as a result of changes in gut microbe function, the researchers wrote in their report. Yet, because of the preliminary nature of their results and the small number of human participants involved, they stopped short of suggesting that people change their eating habits. "By no means are we prepared to make recommendations as to the use and dosage of artificial sweeteners based on the results of this study," said Eran Segal, a study co-author also at the Weizmann Institute of Health. 
 
 Other researchers, however, were more forthcoming. 
 
 "People need to be much more mindful of what they are eating and drinking and make efforts to avoid products that have added sweeteners in any form" said Susan Swithers, a behavioral neuroscientist at Purdue University who wasn’t part of the Nature study, in an email to The Verge. The studies showed not only a causal link between the changes in the gut and artificial sweeteners, but that the observed changes happen quickly, she wrote. 
 
 "People need to be much more mindful of what they are eating and drinking." 
 
 Not everyone agrees with the design the researchers used to address the question about artificial sweeteners and weight gain. Christopher Gardner, a food scientist at Stanford University who didn’t participate in the study, says that the fact that the researchers gave the FDA's maximal acceptable daily intake of saccharin to the human participants — about 5 mg / kg body weight per day — isn’t ideal. In a real-life setting, that dose would be the equivalent to a 150-pound person consuming 42 12-ounce sodas per day, or 8.5 packets of pink Sweet 'n Low per day. "That may be ‘acceptable’ according to some set of guidelines," Gardner wrote in an email, "but it should be noted that realistically this is a very high dose they are using and one that wouldn't be consumed by a typical consumer." 
 
 Still, the idea that we might finally have an explanation for the adverse health effects seen in certain sweetener studies is worth paying attention to. Should the findings prove reproducible, doctors will be tasked with understanding why some people are susceptible to microbiome alterations, while others aren’t. And sweetener companies will have to address the criticism — in addition to rethinking their marketing strategies. "The work is important," Swithers said, "because it underscores the role that artificial sweeteners may play in contributing to the very problems they were designed to help." ||||| Photo: CorrieMiracle (Pixabay) 
 
 For as long as artificial sweeteners have existed, people have been warned about their supposed health risks such as cancer and multiple sclerosis. But while these claims are routinely debunked as nothing more than junk science, some research—including a new study presented this week at the annual Experimental Biology conference—is beginning to indicate that sweeteners could actually contribute to health problems like type 2 diabetes. 
 
 Researchers at the Medical College of Wisconsin and Marquette University used rats vulnerable to developing diabetes for their experiments. For three weeks, different groups were fed high doses of two sugars, glucose and fructose, and two common artificial sweeteners, aspartame and acesulfame potassium. They then studied the rats’ blood using a large-scale technique that tracks minute metabolic changes, known as metabolomics. 
 
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 “Just after three weeks of giving these sweeteners and sugars to our diabetes-susceptible rats, we saw biochemical changes in the blood that could potentially lead to alterations in fat and energy metabolism,” lead author Brian Hoffman, a biomedical engineer at both institutions, told Gizmodo. 
 
 Diabetes is what happens when our bodies become unable to maintain proper glucose levels in the body—a process that’s largely regulated by the hormone insulin. This breakdown causes people to either stop responding to insulin as easily as they once did, or to stop producing insulin altogether. Excessive sugar in our diets is thought to help cause diabetes by overtaxing the body’s insulin-producing machinery, since it’s used to bring high blood glucose levels back to normal. 
 
 Because of that, artificial sweeteners have long been advertised as a way for people to eat treats and soft drinks safely and lose weight, without raising the risk of diabetes. But rates of diabetes and obesity have continued to skyrocket regardless, even as sweetener-rich foods and drinks became widely available starting in the 1950s. (There are currently six FDA-approved artificial sweeteners.) 
 
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 As a result, Hoffman and his team have not only tried to understand how sugar sparks the chain of events that leads to diabetes, but also tried to suss out whether sweeteners could do the same. 
 
 If sweeteners can raise our risk of diabetes, Hoffman says, they probably do it differently than sugar. Rather than overwhelming the body’s machinery, his and others’ research suggests, fake sugar wears it out. “Sweeteners kinda trick the body. And then when your body’s not getting the energy it needs—because it does need some sugar to function properly—it potentially finds that source elsewhere,” Hoffman said. 
 
 In the rats’ blood, his team found evidence of protein breakdown, likely meaning their bodies turned to burning away muscle as a source of energy. They also found higher levels of lipids and other fats, which over time could contribute to obesity and diabetes. Other research has suggested sweeteners alter the community of bacteria that call our guts home—the microbiome—in a way that could lead to harmful metabolic changes. And still more research has shown that diets high in artificial sweeteners are associated with a greater risk of diabetes and obesity. 
 
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 Hoffman is well aware of past efforts to tie sweeteners to dire health risks, but he says things are different in this case. 
 
 “Most of these sweeteners were approved well before we had the technology to perform studies like my lab is doing. So they weren’t able to look as in-depth at some of the potential effects being caused,” he said. “By knowing what biochemical changes these are causing through these large-scale studies, we can take a unbiased approach and see what’s changing to give us a better direction.” 
 
 Hoffman’s team plans to submit their current findings for consideration in several peer-reviewed journals, but they’re already in the middle of studying their sweetener-fed rats for longer periods of time. Future studies are likely to involve taking a peek at the rats’ microbiomes too. Ultimately, he believes their study method could be relatively easy to use with people, since all that would be needed is a blood sample to study small metabolic changes. 
 
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 In the meantime, though, he doesn’t necessarily want to scare anyone away from their diet drink habit. 
 
 “What I like to tell people is that most things in moderation are going to be fine. So if you enjoy your diet soda here and there, than have your diet soda here and there. If you like your normal soda here and there, have it here and there,” he said. “It’s when people start to chronically consume these—say, a person drinks two, three, four of [these drinks] everyday, that we should start to be concerned. Because you’re starting to introduce these biochemical changes and the body has no time to recover.” 
 
 
 
 [EB 2018] 
 
 Update: The American Beverage Association, a trade group that represents the non-alcoholic beverage industry, reached out to Gizmodo after this article was published, and offered this response to the study’s findings: 
 
 “Low-calorie sweeteners have been proven safe by worldwide government safety authorities as well as hundreds of scientific studies and there is nothing in this research that counters this well-established fact.”
– If you're drinking diet soda or consuming other products with artificial sweeteners to cut your risk of obesity and diabetes, a new study published in Nature has some bad news: You might be doing more harm than good. Researchers found that sweeteners such as saccharin, sucralose, and aspartame can interact in a complex way with bacteria in our gut and lead to higher blood-sugar levels, reports the Wall Street Journal. Scientists say studies on both mice and people back up the assertion, though the findings may not apply to all. In one of the human experiments, for example, researchers gave foods with such sweeteners to seven people who normally never consumed them and found that four of the subjects had markedly higher blood-sugar levels in just four days. "In other words: Some people are more susceptible to the effects of artificial sweetener than others," explains the Verge. It all depends, apparently, on your particular microbiome, which the Washington Post describes as the "vast and enigmatic ecosystem of bacteria in our guts." The sweetener industry is already disputing the research, but "the scope of our discovery is cause for a public reassessment of the massive and unsupervised use of artificial sweeteners," says a study co-author at Israel's Weizmann Institute of Science. Far more research is needed before it's definitive, but NPR grabs this quote from the director of the Human Microbiome Program at New York University: "I can just tell you ... as a middle-aged man who's concerned about his diet and his waistline—and [as] somebody who drinks diet soda—I didn't drink any yesterday." (Meanwhile, US bellies are getting bigger.)