Low- and no-calorie sweeteners (LNCS) provide sweetness to foods and beverages without the added calories contained in sugar. LNCS have a long history of safe use and are some of the most studied ingredients in the history of our food supply. Yet they are also among the most scrutinized. Debate often ensues about the safety and health implications of consuming LNCS—sometimes because of valid scientific inquiry, but mostly due to incorrect or misleading information. This article addresses and helps clarify some of the conflicting information you may come across online.

For more in-depth information about the safety of LNCS and how our bodies process them after consumption, check out our free one-hour webinar.

Who approves the use of low- and no-calorie sweeteners in the U.S.?

U.S. law requires the Food and Drug Administration (FDA) to approve the use of food additives, including LNCS such as aspartame and sucralose, before they are authorized for use in foods and beverages. For the review of other food ingredients such as stevia and monk fruit sweeteners, the FDA uses its Generally Recognized As Safe (GRAS) notification program. A GRAS determination does not require pre-market approval by the FDA but does require FDA to scientifically evaluate and publicly respond to submissions made to the agency that supports an ingredient’s safety.

Despite our government’s long-standing oversight authority, uncertainty remains among some Americans about how LNCS are regulated in the U.S. In the IFIC 2023 Food & Health Survey, 20% of respondents said they were unsure who was responsible for approving the use of LNCS.

There are nine types of LNCS permitted by the FDA for use in foods and beverages:

• Acesulfame potassium
• Advantame
• Aspartame
• Monk fruit sweeteners
• Neotame
• Saccharin
• Stevia sweeteners
• Sucralose
• Thaumatin

LNCS are also independently evaluated and carefully regulated by international authorities such as the European Food Safety Authority (EFSA) and the Joint FAO/WHO Expert Committee on Food Additives (JECFA). Decades of published scientific research have repeatedly documented that the LNCS permitted for use in the U.S. and around the world are safe for human consumption within the Acceptable Daily Intake (ADI) established for each type of LNCS. The ADI is the average daily amount of an ingredient that is expected to be safe for a person to consume every day over a lifetime. The ADI varies by body weight and is expressed in milligrams of a substance per kilogram of body weight per day. It is generally established prior to the FDA approving or permitting the use of the proposed food ingredient. In some cases, like for monk fruit sweeteners, the FDA has concluded that an ADI is not necessary if there is “evidence of the ingredient’s safety at levels well above the amounts needed to achieve the desired effect (e.g., as a sweetener) in food.”

The ADI is considered a conservative number because it has a large margin of safety built into it. The ADI is typically set 100 times lower than the amount found to have no adverse health effects in toxicology studies conducted in multiple species of animals. The ADI is not a recommended level of consumption. Instead, the ADI is a range, starting at zero, that can be safely consumed.

Most people consume LNCS in amounts that are well below the ADI. Take aspartame, for example. Even among those who have been documented to consume the most aspartame, there are no reports of people consuming more than the ADI. To exceed the aspartame ADI established by the FDA, a person who weighs 150 pounds would have to consume more than an average of 19 cans of diet soda or more than 85 individual packets of aspartame every day over the course of their lifetime.

Are low- and no-calorie sweeteners safe for children, people with diabetes, and pregnant or breastfeeding women?

ADIs are established to ensure that LNCS are safe for all ages, life stages, and people with health conditions such as diabetes. There is one exception, however. People with phenylketonuria (PKU), a rare hereditary health condition, should avoid or limit their consumption of aspartame and other foods that contain the amino acid phenylalanine.

Children

Proper nutrition early in life is critical for development and helps put us on the path toward maintaining good health throughout our lifetime. Children can safely consume foods and beverages sweetened with LNCS as part of a healthy diet. Although the safety of LNCS is not disputed by professional organizations and official dietary guidance, recommendations have been made about the consumption of LNCS by children. The American Heart Association recommends regular consumption of water and other unsweetened beverages such as plain milk instead of beverages sweetened with LNCS, with some exceptions made for children with diabetes. The American Academy of Pediatrics recognizes that consuming foods and beverages sweetened with LNCS in place of sugar-sweetened varieties may benefit children with diabetes and obesity and may also reduce tooth decay. The 2020–2025 Dietary Guidelines for Americans do not recommend the consumption of LNCS by children younger than two years of age, so that infants and toddlers do not develop a preference for overly sweet foods during these formative years.

People with Diabetes

Diabetes is a serious health condition that affects nearly 40 million Americans. To help control blood glucose levels, people with diabetes are encouraged to carefully monitor their carbohydrate and sugar intake. LNCS are sweet-tasting alternatives to sugar that do not raise blood glucose levels. Experts in medicine and nutrition, along with leading diabetes-focused health authorities such as the American Diabetes Association, Diabetes Canada and Diabetes UK, are in agreement that LNCS can be safely consumed by people with diabetes as part of a healthy diet that provides the appropriate amount of calories and carbohydrates.

Pregnant and Breastfeeding Women

Healthy eating is important during all stages of life, including during pregnancy and while breastfeeding. LNCS can be included in healthy diets during these times, as their safety for pregnant and breastfeeding women has been confirmed by leading health agencies from around the world, including the EFSA, the FDA and the JECFA. However, concerns have been raised about the potential presence of some LNCS in breast milk. Small amounts of sucralose are absorbed into the bloodstream, so it is possible for extremely low levels of sucralose to end up in breast milk. Aspartame will never be present in breast milk because it is rapidly metabolized after consumption into the amino acids phenylalanine and aspartic acid and a small amount of methanol. In sum, regardless of the type, LNCS are considered safe to consume during pregnancy and while breastfeeding, as there are no documented side effects of their consumption within the ADI among expecting and nursing mothers, their fetuses, or nursing babies.

People with Phenylketonuria

Phenylketonuria (PKU) is a rare hereditary condition that makes it difficult for people to metabolize phenylalanine, an amino acid that is part of aspartame and naturally found in many common foods such as cheese, meat, milk, and nuts. People with PKU should avoid or limit sources of phenylalanine in their diet, including aspartame. To help with this monitoring, all packaged food and beverage products in the U.S. that contain aspartame must carry a statement on the label warning people with PKU about the presence of phenylalanine.

Do low- and no-calorie sweeteners cause cancer?

When concerns about the possibility of LNCS causing cancer surfaced in the early 1970s, the news gained the attention of governments, scientists and the general public. Initial studies suggested that saccharin caused bladder cancer in male rats and may similarly affect humans. Through subsequent research, however, it was determined that saccharin does not cause cancer in humans. The biological mechanisms responsible for the development of cancer from saccharin consumption are specific to rats and do not apply to humans.

Since that time, scientists have continued to study potential associations between LNCS and cancer. A few studies over the decades have claimed to demonstrate that LNCS cause cancer, prompting extensive reviews of the methods used to support such conclusions. Independent government and expert evaluations have repeatedly found these studies to be significantly flawed and not of the caliber to be considered in official safety assessments. Government agencies base their safety evaluations on the highest-quality scientific studies, and these studies have consistently shown that consuming LNCS does not cause cancer, nor does it increase the risk of developing cancer.

In 2023, aspartame safety was independently evaluated by two subsidiaries of the World Health Organization: The International Agency for Research on Cancer (IARC) and the Joint FAO/WHO Expert Committee on Food Additives (JECFA). Ultimately, the two entities came to competing conclusions. Based on “limited evidence,” the IARC designated aspartame as “possibly carcinogenic to humans.” This is the same designation that IARC has given aloe vera and pickled vegetables. The JECFA concluded that consuming aspartame does not lead to adverse health effects, including cancer. In its conclusion, the JECFA did not change their previously established ADI and reaffirmed their past scientific reviews that aspartame is safe to consume within the ADI.

Because the two 2023 aspartame evaluations from IARC and JECFA caused confusion, the U.S. FDA weighed in to provide much needed clarity. The U.S. FDA supports the JECFA’s more rigorous scientific review process and disagrees with the IARC conclusion due to the “significant shortcoming in the studies on which IARC relied.”

For more information about research on LNCS and cancer, visit the American Cancer Society and the National Cancer Institute.

Low- and no-calorie sweeteners at a glance

LNCS are often referred to collectively, but each type has unique characteristics. Here’s a quick breakdown of the six most common LNCS that are permitted by the FDA.

Table Source: U.S. Food and Drug Administration