Artificial sweeteners are considered safe for most people, but researchers are investigating their effects on gut microbiome health.

Artificial sweeteners may disrupt gut health

Some research suggests that certain sweeteners can throw off the balance of beneficial bacteria in the gut and shift the composition of the microbiome. Such changes, depending on an individual's specific gut flora and levels of sweetener consumption, could potentially affect metabolism and glucose tolerance or lead to bloating and diarrhea.

Fake sugars may disrupt metabolic health

Alternative sweeteners such as stevia and sucralose are 100 times sweeter than common table sugar. New research suggests these "high-intensity" sweeteners significantly disrupt the composition of the gut microbiome, affecting overall health. (Some users may encounter a paywall.)

Artificial sweeteners aren't very helpful for weight loss

Research published in 2014 from a randomized controlled study found that, on average, people only lost about two pounds if they switched to consuming artificial sweeteners instead of sugar. Some individuals using artificial sweeteners also have gained weight. Scientists theorize one potential explanation for this is that the sweeteners alter gut microbiomes in ways that reduce beneficial flora that would help promote digestion.

Aspartame was a surprise discovery from a lab working on gastric ulcers

As with saccharin and cyclamate, the aspartame discovery arose from its discoverer tasting something sweet from his workplace. In 1965, American chemist James Schlatter licked a white powder off his finger as he picked up a piece of paper and was startled to discover it tasted sweet. He applied for a patent for the substance, and received it in 1970. It is now one of the most popular artificial sweeteners. (Some users may experience a paywall.)

Multiple sugar substitutes were accidental discoveries when lab workers didn't wash their hands

Saccharin, aspartame, and cyclamate all have origin stories from lab workers tasting something sweet on their hands. A Johns Hopkins University worker in the late 1800s, for example, tasted something sweet on his (unwashed or poorly washed) hands during dinner, prompting him to then taste everything on his lab bench in order to identify that the sweetness was a compound derived from his overheated coal tar—a substance he later named saccharin. (Some users may encounter a paywall.)

The WHO labeled aspartame as 'possibly carcinogenic' but US regulators consider it safe

The International Agency for Research on Cancer, an arm of the World Health Organization, labeled aspartame—the artificial sweetener in Diet Coke—as one of several hundred possible cancer-causing substances in 2023. The determination was based on animal and human studies and "limited" evidence linking it to liver cancer. The WHO and US Food and Drug Administration both say the substance is safe at moderate levels. The FDA says a person weighing about 132 pounds would need to have 75 packets daily to reach an unsafe level.

See how sugar stacks up against the sweetness of sugar alternatives

This US Food and Drug Administration graphic compares different approved sugar alternatives to give the public a sense of just how intensely sweet these sweeteners are compared to table sugar. Aspartame (NutraSweet and Equal), for example, is 200 times sweeter, Sucralose (Splenda) is 600 times sweeter, and Saccharin (Sweet'N Low) is between 200 and 700 times sweeter.

Saccharin was banned in Canada in the 1970s, but regulators may allow its use once again

The product, commonly known as Sweet'N Low, was banned in Canada in the late 1970s due to research indicating that the sweetener could cause cancer in lab rats. Subsequent studies have found that the rodent findings didn't hold true for humans, and so Canadian regulators state that they are considering updating their stance to allow the product to be added to certain foods (the product is currently allowed in the US).

Xylitol, a sugar alcohol, is sometimes added to foods at 1,000 times the level seen naturally in foods

This article covers the latest research in sugar alcohols and heart health. Some work indicates that after consuming sugar alcohols erythritol or xylitol people are at an elevated risk of developing blood clots, which can cause heart attacks and strokes. Both substances occur in low levels naturally in fruits and vegetables and are also produced by the human body, but as sweeteners in foods they are present at exponentially higher levels.

See how much daily sugar substitute intake the FDA considers to be safe

The agency states in this PDF graphic that a person weighing about 132 pounds would have to consume roughly a couple dozen sweetener packets daily—or more—to reach unsafe levels of consumption. The accumulated consumption would be across all sources, including diet beverages, sugar-free candies, and actual packets added to coffee.

Saccharin was widely used in WWI when sugar was rationed

The substance was discovered by chemists in 1878, but its use became more common during World War I and also afterward as a result of sugar rationing. It had become a typical household item in the US and Europe by 1917. During World War II, the artificial sweetener again saw significant popularity.

Stevia has been used to treat burns and indigestion

The substance, which is roughly 300 times sweeter than sugar and scientifically known as Stevia rebaudiana, comes from a plant that grows in Paraguay and Brazil. It has long been used medicinally and as a sweetener by indigenous communities in those locations.

Gummy vitamins have candy-level sugar—and that sweetness is linked to overdoses

A typical gummy vitamin contains about the same amount of sugar in a single serving as one Sour Patch candy. It's linked to the increase in pediatric overdoses for products including multivitamins and melatonin. Gummy formulations also degrade quickly, so they often include much higher levels of the product in each serving than the label advertises—boosting overdose risks due to this unchecked variability. (Some users may experience a paywall.)

Cats have a mutation preventing them from tasting sugar

When certain tastes (sweet, umami, bitter) become irrelevant due to a species' diet or lifestyle, the genes for those tastes degrade. In felines, scientists believe a shift to a protein-heavy diet put evolutionary pressure on the genes responsible for tasting sweetness. (Some users may encounter a paywall.)

The dark side of modern sugar production

Humanity's ancestors evolved to wring more calories from sugary fruits by storing excess sugar as fat, an adaption that's culminated in many peoples' palettes preferring calorie-rich sweet. Now, the desire for sugar has both contributed to a widespread health crisis and been at the center of atrocities around the world.

Gut microbiome rewrites may help reduce allergies

Researchers are investigating different strategies to determine if one day they could give people a combination of gut microbes to set them up for fewer allergies. In animal research, scientists have already prevented severe allergic responses in allergy-prone mice—supplying them with gut microbes from healthy, non-allergic human babies.

The myth of sugar rushes vs. the reality of sugar crashes

It's generally accepted that sugar rushes are a myth, and that hyperactivity is a more psychological experience. However, there is real science behind the rare sugar crash that primarily impacts those with diabetes. Read this article to understand how historical and cultural factors have shaped sugar perceptions, and how low blood sugar can trigger shakiness, fatigue, weakness, and more in diabetes patients.

Teddy Roosevelt was given a daily dose of saccharin

America's 26th president was prescribed a sugar-free diet by his clinician, so when the chief chemist for the US Department of Agriculture approached him with concerns about the product's safety in the early 1900s, the duo clashed over how to regulate it.

Kava, kratom, St. John's Wort, and green tea extract present health concerns

Consumer Reports, which tests supplements for safety, urges consumers to avoid these four supplements due to safety warnings from researchers and public health authorities.

Monosodium glutamate is a sodium salt form of a naturally occurring amino acid

Monosodium glutamate myths originate from a 1968 letter to the New England Journal of Medicine, in which unpleasant symptoms after eating Chinese food were dubbed Chinese restaurant syndrome without medical data. Subsequent studies show this savory flavor enhancer—found in tomatoes, mushrooms, and other foods—is safe in moderation.

BPA-free plastics often contain other harmful 'forever chemicals'

These molecules are widely used in single-use plastics, may leach into food, resist breakdown, and can build up in the human body. They have been linked to obesity, heart disease, and neurological issues, particularly when heated.

Acrylamide forms naturally during high-heat cooking through the Maillard reaction

While studies have shown it can damage DNA and potentially cause cancer in mice, humans absorb and metabolize acrylamide at different rates, introducing uncertainty in the research's applicability to humans. Some international health agencies have nonetheless recommended avoiding darker roasts when cooking starchy foods.

The research that led to sour

Scientists are trying to figure out if there are unique receptors that respond to the molecules that make up flavors we associate with calcium, blood, batteries, and other items that often escape dinner menus. Taste researcher Dr. Danielle Reed says the minimum evidence for a taste category typically involves identifying dedicated receptors and then removing them to show the taste vanishes.

Probiotics, which are living bacteria and yeasts, are not recommended for most patients

The American Gastroenterological Association in 2020 concluded that although almost 4 million American adults have taken some form of probiotics, health claims about them are not backed in strong evidence. They only recommend their use for a few specific situations: to prevent Clostridioides difficile infection in people taking antibiotics that kill gut bacteria, to prevent necrotizing enterocolitis in preterm infants, and for the management of a complication of inflammatory bowel disease called pouchitis.

Natural toxins produced on plants or consumed by animals may cause food poisoning

When humans eat plants with certain natural toxins on them—including a family of toxins called aflatoxins that fungi produce on crops like peanuts and corn— they can become ill with food poisoning. Toxins can still harm humans even if animals or plants appear fine to the human eye. The World Health Organization advises that we should throw away moldy or discolored foods, refrain from eating wild plants or mushrooms that aren’t definitively nonpoisonous, and remember that just because something is “natural” it’s not always safe to eat.

GMOs sound scary, but you eat them every day

Why are GMOs bad? They aren’t. We’ve been eating them for decades with no ill effects, which makes sense, because a genetically modified organism is simply an organism, like every other organism, produces hundreds of thousands of proteins, but one or two of them are proteins that were chosen specifically by humans. Watch this 11-minute video for more.

Can the gut microbiome drive addiction?

New research suggests an imbalance of gut microorganisms may influence the likelihood of addiction and addictive behaviors by increasing the severity of withdrawal symptoms, triggering brain inflammation in regions of impulse control, and more.

What constitutes a 'healthy' diet?

A natural diet, typically high in plant-based foods and low in processed foods, appears to be the main contributor to a healthy, diverse gut microbiome.

Investigation finds 'influencer' dietitians paid to promote sugar, supplements on social media

A joint investigation by The Examiner and The Washington Post found that food, beverage, and supplement corporations and groups have paid registered dietitians on social media to promote content that goes against decades of scientific evidence on...

Most people breathe fungal spores daily without getting sick

Most people breathe in hundreds of Aspergillus fumigatus spores daily without getting sick—it’s a common microscopic fungus in our environment. But people who are severely ill, including those who have undergone an organ transplant, are at risk of developing infections from these spores.

The risks of bioremediation, from intermediate products to ecological disruption

A step in the series of complex biochemical reactions involved in the implemented bioremediation process may produce dangerous molecules—sometimes more toxic than the initial pollutants—that require ongoing monitoring to ensure optimal conditions for processing these intermediates toward the eventual, safe outputs. Introducing non-native nutrients or species, including GMOs, may alter existing food webs and gene pools.

Ultraprocessed foods include preservatives, dyes, sweeteners, and more

Processed foods are those that have been altered from their original state, which includes numerous processes that we consider natural, such as cooking or salting. Ultraprocessed foods contain at least one item that wouldn’t be found in a kitchen, like hydrogenated oils or high-fructose corn syrup. It’s estimated that nearly 75% of all foods consumed in the US are ultraprocessed, though that doesn’t mean that all of them are unhealthy. In fact, some, such as prepackaged whole wheat bread and soy milk, are recognized for their health benefits.

The FDA claims microplastics have not yet been shown to pose a health risk

Although microplastics and nanoplastics are found in many foods and environments, their presence does not violate regulations. Additionally, as of 2025, the administration believes evidence does not confirm that detected levels harm humans.

Learn the history of food science breakthroughs from the 20th century

Long after humans developed the means to produce sufficient food to feed civilizations, scientific research focused on a wide variety of objectives, such as developing methods to preserve food quality (accomplished via frozen food), speeding up cooking (leading to the microwave), and lowering the cost of sweetening food, which high fructose corn syrup provides.

Supplements often have issues with impurities, toxins, and inaccurate labels

Consumer Reports' tests of more than 20 supplement powders and shakes in 2025 found that more than two-thirds of them contain unsafe levels of lead. Some contained 10 times the amount of lead that's considered acceptable to ingest in a day. The levels they found, in some cases, were even higher than when they tested the products 15 years earlier.

Reporting if supplements make you ill helps FDA know what products to investigate

The US Food and Drug Administration regulates supplements like foods and can only take action about a supplement if they learn that there are problems with it after it's on the market. This website allows consumers, industry, and others to file a complaint about a product that made them ill or raised other concerns.

Adults are developing food allergies that they didn’t have as children

Research published in 2019 found that almost half of 40,000 surveyed adults with food allergies developed a new food allergy as adults, underscoring that our immune systems may newly misclassify substances later in life.

Tick bites can fuel an allergy to a sugar molecule in red meat

Alpha-gal syndrome is on the rise globally as ticks spread due to climate shifts. Bites from some ticks can trigger a sensitivity to a sugar molecule called alpha-gal found in mammal meat, which can lead to allergic responses to hamburgers and steak, among other products. Listen to an expert’s tips for avoiding this allergy, including quickly removing any ticks to limit exposure to their saliva or vomit.

What's next for gut microbiome science?

A Stanford microbiologist explores what we don't yet know about the gut microbiome—such as whether we can engineer the bacterial species within it—and the current scientific advances in the field.

Differences in the ratio of sugars help distinguish Mexican and American Coke

Mexican Coke is sweetened with cane sugar (sucrose), which dissolves into equal amounts of fructose and glucose, whereas American Coke, which uses high-fructose corn syrup, contains more fructose than glucose.

Not everyone who is a candidate for GLP-1 is choosing to use the drug

One person writes about why, although she's a good fit for the medication on paper, she's decided not to take GLP-1 due to concerns about mental health and other side effects, among other reasons.

Exposing fetuses to certain flavors in the womb could lead to children being less picky eaters

A new study found that 3-year-olds were less averse to the smell of vegetables they had been repeatedly exposed to in utero, suggesting that what mothers eat in late pregnancy can leave a lasting imprint on their children's tastes.

There are up to 100 trillion bacteria in the gut, and maintaining the relative balance of microbes in this ecosystem is important for our health.

Research links the gut microbiome and rheumatoid arthritis

Arthritis is a potentially disabling joint condition that currently affects nearly one in five adults across the globe. Doctors still don't know what causes rheumatoid arthritis, but the answer may be partly determined by chemicals produced by bacteria in the gut.

Even if you have some ASD-linked gene variations you may not develop ASD

Individual environment and life experiences affect how genes perform in the body, potentially adding methyl groups to DNA that affect their function and turning genes on and off—which may heighten or reduce disease risk.

The US FDA issued a 2025 warning about BPC-157 and other popular peptides

BPC-157, which mimics a naturally occurring gut peptide involved in soft tissue repair, has been marketed for various regenerative properties. But the FDA warned in July 2025 that it doesn't have enough data to assess its safety in humans and that such products may also pose risks related to contamination.

Psychedelic side effects, including worsening mental health for some patients, give pause

This article explores whether the therapeutic potential of psychedelic drug use is really as good as current research suggests. Scientists are exploring its applications for conditions ranging from the existential crisis that can accompany terminal diagnoses to chronic mental health conditions, including anxiety and PTSD.

Semaglutides trigger the release of the appetite-suppressing hormone incretin

We've all heard about these new weight loss drugs. But what are they actually doing inside the human body to help people manage their weight? Health news site STAT has created a clear, concise video that explains what GLP-1 RAs are and how semaglutide works.

In the 19th century, ice-cream-related illnesses were somewhat regular in America

Ice cream was a popular dessert, but it was also a dangerous one, with numerous reports of vomiting, diarrhea, and—in some cases—death. Historians argue this was likely due to vendors' poor hygienic practices.

Gut microbiome experiments involving transfers of gut microbes from depressed people to rodents indicate that the rodents may then display depression-like symptoms, underscoring that gut microbes may influence behavior and personality more than previously known.