What research has to say about the risks and benefits of aspartame and other ?fake sugars?
Credit: Roberto Machado Noa/Getty Images
Why drink a soda packed with nearly 40 grams of sugar when there?s a sugar-free alternative that tastes just as sweet? Given the health risks of a diet high in sugar ? experts say consuming too much can pave the way for numerous health problems, from tooth decay to an increased rate of mortality from heart disease ? it?s not surprising that 41% of American adults report consuming at least one artificially sweetened food or drink daily.
While sugary foods and drinks can cause a spike in consumers? blood glucose (which can be risky for diabetics), artificial sweeteners may not cause the same issue in the short-term, making them a good option for anyone who wants or needs to reduce sugar intake. And there?s another draw for anyone who might be concerned about calorie intake or weight: Artificial sweeteners provide fewer calories per gram than sugar. That?s because they are engineered to be sweeter than table sugar or high-fructose corn syrup and can therefore be used in far smaller amounts ? and, according to the USDA, artificial sweeteners aren?t fully absorbed by the digestive system.
Maureen Seel, a registered and licensed dietitian at Johns Hopkins Health in Baltimore, says sweeteners like table sugar and honey, which contain calories, are considered ?nutritive sweeteners,? while calorie-free substitutes are called ?non-nutritive sweeteners.?
?Part of the reason the terminology has changed is that some of the non-sugar sweeteners aren?t necessarily artificial, depending on which ones you buy,? Seel says. ?Things like monk fruit extract or stevia extract are natural and plant-based; however, some of the commercially available products are often blended with chemicals.?
Currently, the FDA has approved eight sugar substitutes: acesulfame potassium (Ace-K or Sweet One), advantame, aspartame (Nutrasweet and Equal), neotame (Newtame), saccharin (Sweet and Low), sucralose (Splenda), siraitia grosvenorii swingle fruit extract (Monk Fruit in the Raw), and steviol glycosides (Stevia or Truvia). (Many diet sodas, like Diet Coke, are sweetened with aspartame, which is 200 times sweeter than sugar.)
According to the FDA, the non-nutritive sweeteners on the market are regarded as safe. But just because these sweeteners are approved for commercial use doesn?t mean they don?t come with any negative effects.
For all the reasons to replace sugar with a non-nutritive sweetener, there are also some objections, including a one-off study on rats that suggested aspartame, the sweetener in Diet Coke, could increase the risk of leukemia and lymphoma. In the study, 1,800 rats were fed aspartame from the age of 8 weeks until their death. Upon examining the rats? bodies after they died, the rats that consumed aspartame had a higher incidence of leukemia and lymphoma.
Follow-up studies haven?t concluded that aspartame causes cancer, and many researchers and nutritionists, including Seel, question the original study?s findings ? one reason is that no human being could drink as many Diet Cokes as it would take to reach a potentially unsafe limit of aspartame consumption (currently, the FDA?s ?acceptable daily intake amount? for aspartame is 50 mg per kg of body weight, so a 150-lb person can allegedly consume 3400 mg daily ? that?s at least 19 cans of Diet Coke.)
?To get the same quantity as the rats in the study, in a human being, would require an IV drip of Diet Coke. You?d have to be drinking it nonstop, 24/7 to get that volume,? says Seel.
More recent research sparked similar, potentially unfounded controversy. In a study (released in 2019) of nearly half a million Europeans over the course of up to 196 years, participants who reported drinking two or more glasses of artificially-sweetened soda daily had a 52% percent higher rate of dying from cardiovascular disease compared with people who drank less than one glass a month.
These stats sound harrowing, but some experts are concerned about these findings, partially because there?s no way to discern whether the diet soda caused the heart-related events or if participants were consuming diet sodas because they were already at a higher risk for heart disease due to obesity.
?One of the things we?re concerned about is reverse causation, which is a bias that happens in observational research,? says Vasanti Malik, ScD, assistant professor of nutritional sciences at the University of Toronto. ?In this case, if you have people who might already be overweight or managing risk factors for cardiovascular disease switching to diet soda, then you could get this ?false positive? for an adverse association with health outcomes.?
?Artificial sweeteners might habituate someone toward a preference for sweets over time, because it could dysregulate how someone perceives ?sweet.??
The jury is still out on the detrimental long-term effects of artificial sweeteners, but Malik says some randomized control trials suggest at least one positive effect: Replacing sugary sodas with diet options can decrease risk factors for major health concerns like cardiovascular disease and diabetes. ?When you compare diet soda to sugar-sweetened drinks, we do see the benefit of replacing sugar,? she says.
As for real, scientifically proven health risks associated with artificial sugar, Malik says reliable data is slim. Part of the concern with diet food products is behavioral: Some people who consume diet drinks might rationalize extra calories elsewhere in their diets, either at the same meal or at another time during the day. (If you?ve ever opted for a large order of fries because you?re drinking a diet soda, you?ve done the same thing.)
Artificial sweeteners can also increase a person?s cravings for sweets ? potentially leading to adverse health outcomes. ?There?s a concern that artificial sweeteners might habituate someone toward a preference for sweets over time, because it could dysregulate how someone perceives ?sweet,?? Malik says. When you increase your threshold for sweetness and an apple no longer satisfies you, you might be more likely to reach for a donut or a cookie to satisfy your craving. Over time, Malik says, heavy sugar consumption can lead to weight gain, which is tied closely to diabetes risk factors.
Artificial sugar has also been linked to adverse changes in gut health in some pilot research. While one study found that saccharine changed rats? microbiome in a way that could contribute to insulin resistance, a smaller study done on humans just implied that it was possible for saccharine to change the gut microbiome, not that there was any particular type of disease risk.
Malik says all of these findings are preliminary, and don?t necessarily provide concrete answers on how non-nutritive sweeteners affect the body: ?In the next five years we will have more answers, but right now the data isn?t consistent.?
One clue to the most significant health risk of non-nutritive sweeteners might be in the name: They simply lack nutrition. Dana Hunnes, senior dietician and adjunct assistant professor in the Department of Community Health Sciences at the UCLA Fielding School of Public Health, says diet foods are often perceived as healthier than other foods, which isn?t always the case. Non-nutritive sweeteners are often found in foods with little to no nutritional value of their own.
?There is some evidence of a ?halo? effect surrounding foods that contain artificial sweeteners in that they are somehow healthier, but often, they are almost as bad or sometimes worse than the original product.?
For example, Hunnes references diabetic patients who eat sugar-free cakes or cookies, even though some of those products have just as many calories and nearly as many carbohydrates as the regular, sugar-sweetened alternatives. The perception that something isn?t as bad could mean overeating calories and generally consuming more processed, chemical-laden food, which does have proven health risks.
But it?s not just diet soda that poses a problem. In general, habitual soda drinking can get in the way of a nutritious lifestyle, especially if it keeps someone from hydrating with water. If you?re drinking a caffeinated beverage in place of water, you?re not only missing out on the hydrating benefits of water; you?re also dehydrating your body.
While Hunnes says she?d probably recommend a patient drink a very small amount of a sugar-sweetened beverage than a large amount of diet soda, in terms of long-term health effects, she says the science just isn?t all there yet. Just as it took time for doctors to discover the link between smoking and cancer, it might take some time for researchers to come up with clear, longitudinal insight on non-nutritive sweeteners. In the meantime, moderation mixed with a bit of caution might be the best approach.