Artificial sweeteners are often the cause of heated debate.
On one hand, they're claimed to increase the risk of cancer and negatively affect your blood sugar and gut health.
This article reviews the evidence on artificial sweeteners and their health effects.
Artificial sweeteners, or sugar substitutes, are chemicals added to some foods and beverages to make them taste sweet.
People often refer to them as "intense sweeteners" because they provide a taste that is similar to table sugar but up to several thousand times sweeter.
Although some sweeteners contain calories, the amount needed to sweeten products is so small that you end up consuming almost no calories ().
Bottom Line: Artificial sweeteners are chemicals used to sweeten foods and beverages. They provide virtually zero calories.
The surface of your tongue is covered by many taste buds. Each taste bud contains several taste receptors that detect different flavors ().When you eat, the different food molecules contact your taste receptors.
A perfect fit between a molecule and a receptor sends a signal to your brain, allowing you to identify the taste ().
For example, the sugar molecule fits perfectly into the taste receptor for sweetness, like a lock and key, allowing your brain to identify the sweet taste.
The molecules of artificial sweeteners are similar enough to sugar molecules that they fit on the sweetness receptor.
However, they are generally too different from sugar for your body to break them down into calories. This is why they have a sweet taste without the added calories.
Only a minority of artificial sweeteners have a structure that your body can break down into calories. Because only very small amounts of artificial sweeteners are needed to make foods taste sweet, you consume virtually no calories ().
Bottom Line: Artificial sweeteners taste sweet because they are recognized by the sweetness receptors on your tongue. They provide virtually zero calories because most cannot be broken down by your body.
The following artificial sweeteners are allowed for use in the US and/or the European Union (, ):
- Aspartame: 200 times sweeter than table sugar. Aspartame is known under the brand names Nutrasweet, Equal or Sugar Twin.
- Acesulfame potassium: 200 times sweeter than table sugar. Acesulfame potassium is suited for cooking and baking and known under brand names Sunnet or Sweet One.
- Advantame: 20,000 times sweeter than table sugar, suited for cooking and baking.
- Aspartame-acesulfame salt: 350 times sweeter than table sugar, and known under the brand name Twinsweet.
- Cyclamate: 50 times sweeter than table sugar. Cyclamate is suited for cooking and baking. However, it's been banned in the US since 1970.
- Neotame: 13,000 times sweeter than table sugar. Neotame is suited for cooking and baking and known under the brand name Newtame.
- Neohesperidin: 340 times sweeter than table sugar. It is suited for cooking, baking and mixing with acidic foods. It is not approved for use in the US.
- Saccharin: 700 times sweeter than table sugar. It's known under the brand names Sweet'N Low, Sweet Twin or Necta Sweet.
- Sucralose: 600 times sweeter table sugar. Sucralose is suited for cooking, baking and mixing with acidic foods. It's known under the brand name Splenda.
Bottom Line: Many different types of artificial sweeteners exist, but not all are approved for use everywhere in the world. The most common include aspartame, sucralose, saccharin, neotame and acesulfame potassium.
Artificial sweeteners are often popular among individuals who are trying to lose weight.
However, their effects on appetite and weight vary among studies.
Effects on Appetite
Some people believe artificial sweeteners might actually increase appetite and promote weight gain ().
They think artificial sweeteners may be unable to activate the "food reward pathway" needed to make you feel satisfied after you eat ().
Because they taste sweet but lack the calories found in other sweet-tasting foods, they're thought to confuse the brain into still feeling hungry (, ).
Additionally, some scientists think you'd need to eat more of an artificially sweetened food, compared to the sugar-sweetened version, in order to feel full.
It's even been suggested that sweeteners may cause cravings for sugary foods ().
Although these theories are plausible, many recent studies do not support the idea that artificial sweeteners increase hunger or calorie intake (, , , , ).
In fact, several studies have found that participants report less hunger and consume fewer calories when they replace sugary foods and beverages with artificially sweetened alternatives (, , , , ).
Bottom Line: Recent studies find that replacing sugary foods or drinks with artificially sweetened ones may reduce hunger and calorie intake.
Effects on Weight
Regarding weight control, some observational studies report a link between consuming artificially sweetened beverages and obesity (, ).
However, randomized controlled studies — the gold standard in scientific research — report that artificial sweeteners may actually reduce body weight, fat mass and waist circumference (, ).
These studies also show that replacing regular soft drinks with sugar-free versions can decrease body mass index (BMI) by up to 1.3–1.7 points (, ).
What's more, choosing artificially sweetened foods instead of those with added sugar may reduce the amount of daily calories you consume.
Various studies ranging from 4 weeks to 40 months show that this may lead to weight loss of up to 2.9 lbs (1.3 kg) (, , ).
Artificially sweetened drinks can be an easy alternative for regular soft drink consumers who want to decrease their sugar consumption.
However, opting for diet soda will not lead to any weight loss if you compensate by eating larger portions or extra sweets. If diet soda increases your cravings for sweets, sticking to water might be best ().
Bottom Line: Replacing sugar-containing foods and beverages with artificially sweetened ones may help you lose some weight.
Diabetics may benefit from choosing artificial sweeteners, which offer the pleasure of sweet taste without the accompanying rise in blood sugar levels (, , ).
However, some studies report that drinking diet soda may increase the risk of developing diabetes by 6–121% (, , ).
This may seem contradictory, but it's important to note that all of the studies are observational. They can't prove artificial sweeteners cause diabetes, only that people likely to develop type 2 diabetes also like to drink diet soda.
On the other hand, many controlled studies show that artificial sweeteners do not affect blood sugar or insulin levels (, , , , , ).
So far, only one small study of Hispanic women found a negative effect.
Women who drank an artificially sweetened drink before a sugary drink had 14% higher blood sugar levels and 20% higher insulin levels, compared to those who drank water before the sugary drink ().
However, the participants weren't used to drinking artificially sweetened drinks, which may partially explain the results. What's more, artificial sweeteners may have different effects based on people's age or genetic background ().
For example, research shows that replacing sugar-sweetened beverages with artificially sweetened ones produced stronger effects among Hispanic youth ().
This could be related to the unexpected effect seen on Hispanic women above.
Although not unanimous, the current evidence is generally in favor of artificial sweetener use among diabetics. That said, more research is needed to evaluate the long-term effects in different populations.
Bottom Line: Artificial sweeteners can help diabetics reduce the amount of added sugar in their diets. However, more research is needed into the effects on different populations.
Metabolic syndrome refers to a cluster of medical conditions including high blood pressure, high blood sugar, excess belly fat and abnormal cholesterol levels.
These conditions increase your risk of chronic diseases such as stroke, heart disease and type 2 diabetes.
Some studies suggest diet soda drinkers could have up to a 36% higher risk of metabolic syndrome ().
However, higher-quality studies report that diet soda either has no effect or a protective one (, , ).
One recent study provided overweight and obese participants with either a quarter gallon (1 liter) of regular soda, diet soda, water or semi-skimmed milk each day.
By the end of the six-month study, participants drinking the diet soda had striking differences compared to those drinking regular soda.
They weighed 17–21% less and had 24–31% less belly fat, 32% lower cholesterol levels and 10–15% lower blood pressure ().
Water had the same benefits as diet soda, compared to regular soda ().
Bottom Line: Artificial sweeteners are unlikely to promote metabolic syndrome. Replacing sugary drinks with artificially sweetened ones might actually decrease the risk of several medical conditions.
Your gut bacteria play an important role in health, and poor gut health is linked to numerous problems.
These include weight gain, poor blood sugar control, metabolic syndrome, a weakened immune system and disrupted sleep (, , , , , ).
The composition and function of gut bacteria varies between individuals and seems to be affected by what you eat, including artificial sweeteners (, ).
In one recent study, the artificial sweetener saccharin disrupted the gut bacteria balance in four out of seven healthy participants not used to consuming them.
The four "responders" also showed worse blood sugar control as little as five days after consuming the artificial sweetener ().
What's more, when the gut bacteria from these people were transferred into mice, the animals also developed poor blood sugar control ().
On the other hand, the mice implanted with the gut bacteria from "non-responders" had no changes in their ability to control blood sugar levels ().
Although interesting, this is the only study to date showing these effects in humans. More studies are needed before strong conclusions can be made.
Bottom Line: Artificial sweeteners may disrupt the balance of gut bacteria in some people, which could increase the risk of disease. However, more studies are needed to confirm this effect.
A debate has raged since the 1970s about whether there is a link between artificial sweeteners and cancer risk.
The debate was ignited when animal studies found an increased risk of bladder cancer in mice fed extremely high amounts of saccharin and cyclamate ().
Luckily, the metabolism of saccharin is different in mice and humans.
Since then, more than 30 studies performed in humans have found no links between artificial sweeteners and the risk of developing cancer (, , , ).
One such study followed 9,000 participants for 13 years and analyzed their artificial sweetener intake. After accounting for other factors, the researchers found no link between artificial sweeteners and the risk of developing various types of cancer ().
A recent review analyzed studies that had been published over an 11-year period. It also did not find a link between cancer risk and artificial sweetener consumption ().
This was also evaluated by US and European regulatory authorities. Both agreed that artificial sweeteners, in recommended amounts, do not increase cancer risk (, ).
One exception is cyclamate, which was banned for use in the US after the original mouse bladder cancer study came out in 1970.
Since then, extensive studies in animals have failed to show a cancer link. However, cyclamate was never re-approved for use in the US ().
Bottom Line: Based on the current scientific evidence, artificial sweeteners are unlikely to increase the risk of cancer in humans.
Dental caries — also known as cavities or tooth decay — occur when the bacteria in your mouth ferment sugar. Acid is produced, which can damage tooth enamel.
Unlike sugars, artificial sweeteners do not react with the bacteria in the mouth. This means they do not form acids and therefore do not cause tooth decay ().
Research also shows that sucralose is less likely to cause tooth decay than sugar.
For this reason, the US Food and Drug Administration (FDA) authorizes products containing sucralose to claim that they reduce tooth decay (, ).
The European Food Safety Authority (EFSA) states that all artificial sweeteners, when consumed in place of sugar, neutralize acid and help prevent tooth decay ().
Bottom Line: Artificial sweeteners, when consumed instead of sugar, decrease the likelihood of tooth decay.
Some artificial sweeteners may cause unpleasant symptoms such as headaches, depression and seizures, at least in some individuals.
While most studies find no link between aspartame and headaches, two note that some people are more sensitive than others (, , , , ).
This individual variability may also apply to aspartame's effects on depression.
For instance, individuals suffering from mood disorders may be more likely to experience depressive symptoms in response to aspartame consumption ().
Finally, artificial sweeteners do not increase most people's seizure risk. However, one study reported increased brain activity in children with absence seizures (, , ).
Bottom Line: Artificial sweeteners are unlikely to cause headaches, depression or seizures in most people. However, some individuals could be more sensitive to these effects than others.
Artificial sweeteners are generally considered safe for human consumption ().
They are carefully tested and regulated by US and international authorities to make sure they are safe to eat and drink.
That said, some individuals should avoid consuming them. For example, aspartame contains the amino acid phenylalanine.
Individuals with the rare metabolic disorder phenylketonuria (PKU) cannot metabolize it. People who have PKU should therefore avoid aspartame.
In addition, some people are allergic to the class of compounds that saccharin belongs to, called sulfonamides. For them, saccharin may lead to breathing difficulties, rashes or diarrhea.
Bottom Line: Artificial sweeteners are generally considered safe but should be avoided by people with phenylketonuria or those allergic to sulfonamides.
Overall, the use of artificial sweeteners poses few risks and may even have benefits for weight loss, blood sugar control and dental health.
These sweeteners are especially beneficial if you use them to decrease the amount of added sugar in your diet.
That said, the likelihood of negative effects can vary from one individual to another.
Some people may feel bad or experience negative effects after consuming artificial sweeteners, even if they are safe and well-tolerated by most people.
If you'd like to avoid artificial sweeteners, make sure to check out these four healthy, natural sweeteners that are actually good for you.