Are artificial sweeteners bad for you?

Despite decades of research attempting to answer this question, most experts aren’t sure.

Some say they’re benign or even somewhat beneficial if they’re substituted for caloric sweeteners like sugar. 

Others claim even the tiniest amounts (like that found in a stick of sugar-free gum) pose a serious health risk.

In this article, we’ll look at what science says about the health effects of eating artificial sweeteners, so you can decide for yourself whether you should consume them. 

What Are Artificial Sweeteners?

Artificial sweeteners, also known as “sugar substitutes” or “high-intensity sweeteners,” are chemicals used to sweeten foods. 

They come in two types: Nutritive and non-nutritive sweeteners. Nutritive sweeteners contain calories, while non-nutritive sweeteners contain few or no calories.

Artificial sweeteners are far sweeter than table sugar (up to 20,000 times sweeter), which means you only need to use a tiny amount to achieve a similar level of sweetness.

There are six FDA-approved artificial sweeteners:

  1. Advantame: Advantame is approximately 20,000 times sweeter than sugar and contains no calories.
  2. Acesulfame potassium: Acesulfame potassium (also called acesulfame K, acesulfame potassium, or Ace-K) is sold under the brand names Sunett and Sweet One. It’s ~200 times sweeter than sugar, contains no calories, and is often combined with other sweeteners.
  3. Aspartame: Aspartame brand names include Nutrasweet, Equal, and Sugar Twin. It’s ~200 times sweeter than sugar and contains 4 calories per gram.
  4. Neotame: Neotame is sold under the brand name Newtame, is ~7,000-to-13,000 times sweeter than sugar, and contains no calories.
  5. Saccharin: Saccharin brand names include Sweet and Low, Sweet Twin, Sweet’N Low, and Necta Sweet. It’s ~200-to-700 times sweeter than sugar and contains no calories.
  6. Sucralose: Sucralose is sold under the brand name Splenda, is ~600 times sweeter than sugar, and contains no calories.

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Are Artificial Sweeteners Bad for You?

People fear that artificial sweeteners harm health in many ways, but the most common concerns are that they cause cancer, diabetes, and weight gain and damage your gut health.

Let’s look at what science says about each of these worries.

Artificial Sweeteners and Cancer

The fear that artificial sweeteners cause cancer dates back to 1970 when a study showed that mice that consumed huge amounts of saccharin and cyclamate (an artificial sweetener that the U.S. regulatory authority subsequently banned) had an increased risk of bladder cancer.

Over the following decades, multiple studies showing no link between artificial sweeteners and cancer risk in humans tempered these concerns.

Recently, a large cohort study conducted by scientists at Sorbonne Paris Nord University rewakened this worry when it found that people who consume artificial sweeteners (particularly aspartame and acesulfame-K) had a higher risk of cancer than those who didn’t.

While a cursory glance at these results paints an unsettling picture, a more thorough reading uncovers a couple of reasons to be wary of the findings.

First, it was an observational study, which means it can only show that artificial sweeteners and cancer are correlated, not that one causes the other. 

Given that the artificial sweetener consumers with the highest cancer risk were also more likely to smoke, be less physically active, have diabetes, and eat less fruit, fiber, vegetables, and whole grains and more salt and sugar than those who didn’t eat artificial sweeteners, other confounding variables likely contributed to their higher cancer risk.

Second, the researchers found that people who ate artificial sweeteners in small amounts had a higher cancer risk than those who ate them in large amounts. This is strange since if artificial sweeteners “cause” cancer, you’d expect to see a dose-response relationship, where the more you eat, the higher your risk of cancer—but this isn’t the case.

It’s also worth putting the findings of this study into perspective. 

Based on the findings, many media outlets reported that artificial sweeteners “increase cancer risk by 13%,” which is a scary thought. This isn’t exactly what the study found, though.

The results actually showed that people who consume artificial sweeteners have a 13% relative increase in cancer risk compared to those who don’t. A relative increase, however, isn’t the same as an absolute increase.

For example, if you usually have a 5% risk of cancer, and you eat artificial sweeteners, causing a relative increase in cancer risk by 13%, your overall cancer risk is now 5.65% (your overall cancer risk would only jump to 18% if it were an absolute increase).

In other words, even if we were to take these results at face value, the effect of artificial sweeteners on cancer risk is relatively small—smaller than the effect of eating red meat on cancer risk, according to some research.

At bottom, most studies suggest there’s no link between artificial sweetener intake and cancer, and those indicating otherwise show that any risk is negligible. As such, it’s probably safe to conclude that artificial sweeteners have either no or minimal effect on cancer risk.

Artificial Sweeteners and Diabetes

While there appears to be an association between artificial sweeteners and diabetes, we don’t yet understand whether artificial sweeteners contribute to or help prevent diabetes.

For instance, several studies have shown that artificial sweeteners don’t raise blood sugar or insulin levels in humans. This is typically beneficial for metabolic health (and thus diabetes risk) since maintaining relatively low blood sugar and insulin levels is generally better than having high levels.

Conversely, several observational studies have linked consuming artificial sweeteners with an increased risk of developing type 2 diabetes. 

Again, observational studies can’t tell us that artificial sweeteners cause diabetes, only that people who develop diabetes also regularly consume artificial sweeteners. Nonetheless, this suggests a connection between consuming artificial sweeteners and diabetes risk.

Animal research muddies the waters further.

Some studies on rodents and animal cells show that artificial sweeteners “disrupt” the gut microbiome (the microbes in your intestines), triggering the release of inflammatory proteins that interfere with insulin’s ability to remove glucose from the blood, which could lead to insulin resistance and diabetes.

Others, however, show that rats given artificial sweeteners produce more short-chain fatty acids.

Short-chain fatty acids are compounds produced by the “friendly bacteria” in your gut that are crucial for maintaining optimal metabolic and intestinal health and that may increase fat burning, limit fat storage, and fight inflammation, all of which can help you avert diabetes.

Since most human research suggests that artificially sweetened food and drinks are generally better for metabolic health than sugary alternatives, it’s likely safe to consume them in moderation. 

Still, we need more long-term human research before we can definitively say that artificial sweeteners positively affect diabetes risk.

This is really the biggest rub with artificial sweeteners: we just aren’t sure what the long-term effects are for all of them. 

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Artificial Sweeteners and Weight Gain

Artificially sweetened food and drinks typically contain fewer calories than sugary alternatives, so many people use them to aid weight loss. Research on how artificial sweeteners affect body weight isn’t always clear, though.

For example, while there’s evidence that artificial sweeteners increase your appetite and cravings for sweet treats and thus contribute to weight gain, other research shows that people who substitute sugar-sweetened food and drinks with artificially sweetened fare feel less hungry, eat fewer calories, and find losing weight easier.

What’s more, multiple observational studies have uncovered a link between consuming artificial sweeteners and obesity. However, most randomized controlled trials (the “gold standard” of scientific research) show consuming artificial sweeteners in place of sugar aids fat loss.

Given the results of the highest-quality research, it’s safe to assume that artificial sweeteners aid weight loss for most people.

Artificial Sweeteners and Gut Health

Your gut microbiome and the fermented products it creates are key to numerous aspects of your health, including your body weight, insulin sensitivity, metabolic health, immune function, and sleep.

Most human and animal studies show that artificial sweeteners alter the composition of your gut microbiome, which means they could affect your health—though not necessarily negatively.

For example, as we’ve already seen, artificial sweeteners increase short-chain fatty acid production. While research suggests this reduces appetite and increases calorie and fat burning in animals, some human research has tentatively linked it to obesity. One way it might do this is by enabling the body to “extract” more energy (calories) from foods that would otherwise pass through your body undigested.

That said, other human and human cell studies have found that short-chain fatty acids may regulate appetite and increase energy expenditure. This would likely improve body weight and thus insulin sensitivity and metabolic health. 

There are three more studies in living humans worth mentioning.

In one, researchers found that the gut microbiome of 4 out of 7 healthy people changed after consuming large amounts of saccharin, which inhibited how their bodies’ controlled blood sugar for as long as 7 days after the trial.

In another, researchers found that saccharin, sucralose, aspartame, and stevia altered the gut microbiome in healthy people, and that saccharin and sucralose elevated blood sugar levels.

And in the last, researchers found that feeding people large amounts of saccharin had no effect on the gut microbiome or blood sugar control.

Given the conflicting evidence, it’s too early to say whether artificial sweeteners damage gut health or not. Until scientists conduct more research in humans, the safest bet is to consume artificial sweeteners in moderation or not at all.

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Research on how artificial sweeteners affect human health is still early days, so it’s hard to draw firm conclusions about their long-term effects.

That said, current evidence suggests that artificial sweeteners aren’t the health hazard many claim they are. If they increased disease risk and ruined our metabolic health the way some suppose, long-term trials probably would have served up more hints this is the case—but they haven’t.

In most cases, studies report negligible effects on metabolic health, with some suggesting artificial sweeteners offer some benefits.

Still, there are plenty of tip-offs in the literature to suggest artificial sweeteners aren’t all good. Thus, the best thing to do for now is to consume them in moderation or not at all. 

It’s also important to remember that every artificial sweetener is a unique molecule with its own effects on the body. Just because one artificial sweetener is proven to be relatively safe or unsafe doesn’t mean you can apply those findings to the rest of them. 

In other words, you need to look at each one individually when deciding what the risks and benefits are. 

+ Scientific References