A new study says sugar substitutes make for an effective weight loss tool—but are they safe?
Image by Raysonho @ Open Grid Scheduler / Grid Engine via Wikimedia Commons
Americans are caught in a confusing, potentially high-stakes debate on how we ought to feel about the proliferation of artificial sweeteners. A discrete phenomenon, from the outside this might seem like a petty concern that could easily be resolved with a few decisive statements form respected authorities. But that’s just not the case. Almost every year, some new op-ed or study comes out worrying about the potential medical risks of these substances or trying to assuage such fears—and the public and wider media sphere inevitably pounce upon it with vitriolic commentary and seemingly contradictory evidence. It’s a mess of a debate, and it’s been that way for decades now.
Now, a new meta-study seems like it could jump-start the debate once again. Synthesizing the results of 330 previous scholarly investigations on the effects of artificial sweeteners on weight, University of Bristol researchers suggest this month in the International Journal of Obesity that artificial sweeteners are actually pretty decent weight management tools. So why is this debate so persistent, anyway? How did artificial sweeteners get so controversial? Taking a cue from the new study’s comprehensive approach, we decided to recap the literature on artificial sweeteners. It seems safe to say that, although they require more study, artificial sweeteners are not a real health risk, and could indeed be a helpful public health stopgap.
It’s worth differentiating between artificial sweeteners and other sugar alternatives. Although consumers will always find something to take issue with in any food, the debate over artificial sweeteners does not encompass the use of natural sugars like agave, date sugar, fruit juice concentrate, honey, maple syrup, or molasses, all caloric alternatives to refined white sugars, which have become public health enemy No. 1 in America in recent years. Nor do these debates usually encompass sugar alcohols, which are either naturally occurring or modified sugars often used for making reduced-calorie and tooth-friendly candies, cookies, and gums.
Usually when we talk about artificial sweeteners we’re talking about the six U.S. Food and Drug Administration-approved synthetic additives: advantame, aspartame, acesulfame potassium (ace-k), neotame, saccharin, and sucralose. Increasingly, though, the conversation encompasses supposedly natural sugar alternatives like stevia, a sweet compound made from the leaves of a Paraguayan shrub, or mogrosides, made from the Chinese monk fruit, which are often marketed by the same companies that produce synthetic sweeteners. These recent additions to the sweetener family have come under fire for marketing themselves as wholly natural although they involve a great deal of laboratory tweaks and synthetic modifications to function for an American palate. Each of these substances works a bit differently, but they’re all metabolized (or not) in such a way as to sweeten our foods—usually drastically more efficiently than refined white sugar by volume—without contributing empty calories to our diet.
We like to think about artificial sweeteners as a very modern phenomenon, but saccharin has been around since 1879 and came into heavy rotation in the food industry in the early 1900s to alleviate the stress of wartime rationing. In the latter half of the 20th century, food manufacturers and then health proponents re-engaged with these substances to mitigate concerns about added sugars, especially in soft drinks; today up to 60 percent of artificial sweeteners consumed are in beverages, as we have come to understand the threat that sweet drinks pose to our waistlines. The first diet drink, a soda developed in 1904 by a doctor in New York City so that his diabetic patients could enjoy sweet things without a risk to their blood sugar levels, went viral in 1952, marketed to wider audiences as a weight-loss miracle.
Unfortunately for the artificial sweetener industry, the additive used in these first beverages, cyclamate, while approved for human consumption by the FDA in 1951, was banned in the United States in 1969 for reliably causing bladder cancer in rats. This set up a sense of mistrust between consumers and the FDA—a mistrust that was only augmented in the ‘70s as new artificial sweeteners like aspartame and saccharin came onto the market and saccharin came under fire for its own correlations with cancer in rats. Over the next few decades, a flurry of rumors, commonsense arguments, and controversial studies linked all the major artificial sweeteners to cancer and improper or insufficient FDA testing. The most prominent of these studies was perhaps a 1996 article suggesting that the rise of aspartame use correlated to an increase in brain tumors. But even more recently, a study from about a decade ago argued that drinking artificially sweetened sodas every day could be linked to a notably increased risk of blood-born cancers like non-Hodgkin lymphoma in men.
Image by Mike Mozart via Flickr
In recent years, these concerns have been bolstered by new studies arguing that artificial sweeteners don’t even accomplish what they set out to do—manage our weight. Over the past decade, numerous rat and human studies have suggested that those who use these sugar substitutes might actually gain more weight, consume more food, or even suffer greater risks of diabetes and heart failure than the general population. The mechanisms behind these effects are unclear, but many think they have to do with the fact that artificial sweeteners rewire our association between sugars and calories, prime us to eat more sweet things, have cascading metabolic effects on how our bodies deal with other sugars, or maybe even alter our gut’s bacterial biome in adverse and frightening long-term ways.
Yet for all this gloom and doom, most major health organizations stand behind the safety of artificial sweeteners from a cancer-risk perspective. And many academics and health officials question the validity of studies suggesting both cancer links and wider ill effects. Many studies, like the famous paper linking aspartame and brain tumors, are based on circumstantial and poor evidence, or, like the blood cancer paper, use weak and inconsistent findings to make their arguments. Many more, like those on gut biome changes, extrapolate data from rats, whose metabolic systems are radically different from those of humans—a jump even the researchers in those studies caution against making wantonly. Still more studies show an adverse effect from sweeteners on humans only when there’s an insanely high level of product intake. There is no convincing link between any of these sweeteners and cancer at accepted doses. And while people with a rare condition called phenylketonuria are cautioned against consuming aspartame, there are no other widely recognized health complications associated with artificials save individual sensitivities causing headaches or upset stomachs. Beyond that we just have correlations, not causations—limited concerns that could well be caused by some other factor and that deserve further study, but do not yet merit more than commonsense caution.
Conversely, a number of studies over the past five years support the idea that artificial sweeteners actually do achieve their intended purpose—managing weight and caloric intake amongst those who would otherwise consume a ton of added sugars. The recent study mentioned at the top of this piece makes a very convincing argument, based on a synthesis of hundreds of other studies, that using artificial sweeteners correlates strongly to reduced calorie intake and body weight compared to sugar consumption. Even when compared to water consumption in place of sugary beverages, artificially sweetened drinks seemed like an effective weight loss aid, as these sweetened drinks may better satiate our cravings.
There are almost inevitably flaws within these meta-studies as well. Most of the sub-studies’ results seem to support the industry that sponsored them—studies sponsored by the artificial sweetener industry favored the safety of their products and those paid for by the sugar business tend to cast doubt on that safety. So even a powerful meta-synthesis article, like the recent University of Bristol project, is limited by the material with which it’s working. In order to make truly convincing claims either way about artificial sweeteners, we need more independent and robust clinical and controlled studies on the effects of consuming each individual product in mass human populations.
But barring those studies, which would take years to complete even if the money and support for them were to kick into gear right now, the existing evidence seems to tip in favor of a moderate use of artificial sweeteners. That’s not an endorsement of these sweeteners as “good for you.” It’s an endorsement of artificial sugars as a less harmful and a mostly inert replacement for added sugars, which have a ton of known, frightening effects on our health and for which we desperately need effective alternatives. It’s a simple claim that these products do seem, in humans and in most studies, to work as necessary weight management stopgaps.
Even so, weight management and health concerns would both be better served if Americans could cut down on their intake of sweets and sweetened products in general. Tempering our sweet teeth is the only way to truly mitigate the known dangers of refined sugars and hypothetical dangers of artificial sweeteners. We may be witnessing that shift, as sweetened soda intake continues to drop dramatically in the United States (consumption fell 12 percent from 2008 to 2014) and as we become more aware of the risks posed by excess sugar consumption. But culture-wide behavioral and taste changes like these are piecemeal and gradual. This ideal solution will not come online for at least a generation—perhaps longer. In the meantime, although it may not be a popular opinion, it seems like an inevitable necessity that we embrace artificial sweeteners and acknowledge the evidence supporting their merits as a tool to mitigate the risks of refined sugars. If we treat them simply as that—a culinary methadone—rather than as miracle chemicals, we may just be able to extricate ourselves from these endless debates and refocus our attention on the real, wider health concerns.