Aspartame Safety: ADI, Metabolism and Common Concerns

“Aspartame is one of the most thoroughly studied food ingredients, with more than 200 scientific studies confirming its safety. ”

Aspartame Safety: ADI, Metabolism and Common Concerns

Aspartame is one of the most thoroughly studied food ingredients, with more than 200 scientific studies supporting its use. It is used in more than 6,000 products around the world.

Discovered in 1965 and approved for use by the U.S. Food & Drug Administration (FDA) in 1981, aspartame is permitted for use in food and beverage products in more than 100 countries around the world. Authorities that have recognized and/or approved aspartame include the Joint FAO/WHO Expert Committee on Food Additives (JECFA), the U.S. Food and Drug Administration (FDA), the European Food Safety Authority (EFSA) and the Agence Française de Sécurité Sanitaire des Aliments (French Food Safety Agency – AFSSA). In 2013, EFSA reaffirmed the safety of aspartame, following the “most comprehensive review of aspartame that has ever been undertaken.”

Aspartame is safe for use by nearly all populations. The only exception is people born with a rare genetic disorder called phenylketonuria (PKU). People with PKU cannot metabolize a common amino acid called phenylalanine and therefore need to avoid foods and beverages that contain it. Phenylalanine is primarily found in protein foods, including milk, milk products, eggs and meats. It is also a component of aspartame. The regulations of most countries require that aspartame-containing foods and beverages carry a statement on the label alerting people with PKU to the presence of phenylalanine.

Acceptable Daily Intake (ADI)

Before any food additive, including aspartame, is allowed to be used in foods and beverages, independent scientific experts established an Acceptable Daily Intake (ADI) for the ingredient. The ADI is based on a detailed review of all the available scientific data from both human and animal studies and is defined as the maximum daily dietary level of the ingredient that can be ingested daily over a lifetime without appreciable risk to human health. The ADI is an “acceptable” level of daily intake. It includes a large margin of safety to ensure that it is virtually certain that no harm would result even if the sweeteners are consumed at that ADI level every day for an entire lifetime.

In the U.S., the FDA is responsible for setting the ADI for all food additives, including aspartame. In other countries, ADIs are established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and the European Food Safety Authority (EFSA). The US FDA has set the ADI for aspartame at 50 mg/kg body weight for adults and children. The amount of low- and no-calorie sweeteners used to sweeten foods and beverages is very small, and far below ADI levels. For example, a 154-pound (70 kg) person would need to drink about 18 12-fl. oz. cans per day of a diet soda sweetened solely with aspartame in order to exceed the ADI (assuming no other sources of aspartame are in the diet).

Consumption of food additives is monitored. Research on aspartame showing that amount consumed by all population groups in the U.S. and globally is far below ADI levels.


Aspartame is fully metabolized into compounds that are commonly found in other foods and beverages.

When aspartame is digested, the body breaks it down into its three components: the amino acids aspartic acid and phenylalanine and methanol. The aspartic acid and phenylalanine derived from digesting aspartame are chemically the same as those obtained from protein-rich foods such as eggs, meat, fish, cheese, dairy products and nuts. Methanol is also a common component of many foods, including ripening fruit and juices, and is also present and permissible in various other foods, including spices and spice extracts.

In its 2013 review of aspartame safety EFSA also evaluated the effects of aspartame’s metabolite, methanol. It found that: “By far the largest amount of methanol in humans (some 90% on average) is produced naturally by the body from the consumption of pectin-containing fruits such apples and citrus fruits. Methanol is a safety concern when exposure is extremely high, such as from consumption of some home-distilled alcoholic spirits.

Based on the available scientific evidence, EFSA’s experts concluded that dietary exposure to methanol including from aspartame would not cause adverse effects as it constitutes only a very small portion compared to the natural production by the body. They also concluded that methanol from aspartame is processed by the body in the same way as methanol derived from other dietary sources.” (Read full EFSA report here)

Phenylalanine, Aspartic Acid & Methanol Content of Common Foods (mg)

Food/Beverage Portion Size Phenylalanine* Aspartic Acid* Methanol
Diet Coke 8 fl. oz. (240 ml) 60 48 12
Milk 8 fl. oz. (240 ml) 404 592
Tomato juice 8 fl. oz. (240 ml) 39 231 71
Banana medium 58 146 21

* Amino acids

How much aspartame do people consume?

Food safety experts routinely monitor the amount of aspartame and other food additives consumed relative to their ADI to ensure consumption is well within safe levels, even at highest estimated intakes by adults and in children. The chart below shows the estimated daily intakes of aspartame around the world are well below the ADI.

Aspartame Intakes (Estimated) vs. ADI

United States¹

Low- and No- Calorie Sweetener Users Est. Aspartame Intake
mg/kg bw/day
Percent of ADI
(ADI=50 mg/kg bw/day) FDA ADI
All Low-Calorie Sweetener Users
50th Percentile 4.8 10%
95th Percentile 13.3 27%
Children, 6-11 yrs (subgroup)
50th Percentile 5.5 11%

Low- and No- Calorie Sweetener Users Est. Aspartame Intake
mg/kg bw/day
Percent of ADI
(ADI=40 mg/kg bw/day) JECFA ADI
All Low-Calorie Sweetener Users
50th Percentile 3.4 9%
95th Percentile 10.4 26%
Children, 1-5 yrs
90th Percentile 2.8 7%

Low- and No- Calorie Sweetener Users Est. Aspartame Intake
mg/kg bw/day
Percent of ADI
(ADI=40 mg/kg bw/day)
All Low-Calorie Sweetener Users
50th Percentile 0.14 0.35%
90th Percentile 4.6 12%
Children, 6-11 yrs (subgroup) 0.6 1.5%

Low- and No- Calorie Sweetener Users Est. Aspartame Intake
mg/kg bw/day
Percent of ADI
(ADI=40 mg/kg bw/day)
All Low-Calorie Sweetener Users
50th Percentile 2.56 6%
90th Percentile 5.3 13%
New Zealand4

Low- and No- Calorie Sweetener Users Est. Aspartame Intake
mg/kg bw/day
Percent of ADI
(ADI=40 mg/kg bw/day)
All Low-Calorie Sweetener Users
50th Percentile 1.69 4.2%
90th Percentile 3.9 10%

Chart References:

  1. 2001-2002 US National Health and Nutrition Examination Survey (NHANES)
  2. Scientific Committee on Food. (2002) Opinion of the Scientific Committee on Food:Update on the safety of aspartame. SCF/CS/ADD/EDUL/222 Final. Brussels:European Commission.
  3. Chung MS, et al. Daily intake assessment of saccharin, stevioside, D-sorbitol and aspartame from various processed foods in Korea. Food Additive Contaminants 2005;22 (11): 1087-97
  4. New Zealand Food Safety Authority

Aspartame Safety Affirmed

In 2013, the European Food Safety Authority (EFSA) reaffirmed that aspartame is safe, following the most comprehensive review of aspartame that has ever been undertaken. EFSA had previously confirmed the safety of aspartame in 2006, 2009, and 2011.

Cancer: In its 2013 review, EFSA reported that “Aspartame has been tested for genotoxicity in a number of in vitro and in vivo studies” and that “Overall, the (Expert) Panel concluded that the available data do not indicate a genotoxic concern for aspartame.” The Panel also noted “there was no epidemiological evidence for possible associations of aspartame with various cancers in the human population.” Previously in 2011, EFSA investigated suggestions by two studies published in 2010 that alleged an association between aspartame exposure in mice with the development of carcinogenic tumors [Soffritti et al.] and an association between the consumption of artificially-sweetened drinks with premature birth [Halldorsson et al. (2010)]. With regard to the Soffritti study, EFSA concluded that “the validity of the study and its statistical approach cannot be assessed and that its results cannot be interpreted. Furthermore, in view of the generally recognised lack of relevance for human risk assessment of the type of tumours observed in Swiss mice when they are induced by non-genotoxic compound, EFSA concluded that the results presented in Soffritti et al. (2010) do not provide a sufficient basis to reconsider the previous evaluations by EFSA on aspartame.” With regard to Halldorsson et al. study, the agency stated that “EFSA assessed this study and concluded that there is no evidence available to support a causal relationship between the consumption of artificially sweetened soft drinks and preterm delivery” and that “ (o)verall EFSA concluded that the information available from the Soffritti et al. (2010) and Halldorsson et al. (2010) publications do not give reason to reconsider the previous evaluations of aspartame or of other food additive sweeteners authorised in the European Union.”

An analysis by the National Cancer Institute (NCI) in 1996, conducted to address questions regarding the safety of aspartame raised by a report suggesting that an increase in brain tumor rates between 1975 and 1992 might be associated with the introduction of aspartame in the United States, “showed that the overall incidence of brain and central nervous system cancers began to rise in 1973, 8 years prior to the approval of aspartame, and continued to rise until 1985. Moreover, increases in overall brain cancer incidence occurred primarily in people age 70 and older, a group that was not exposed to the highest doses of aspartame since its introduction.” Subsequently in 2006, the NCI further “examined human data from the NIH-AARP Diet and Health Study of over half a million retirees. Increasing consumption of aspartame-containing beverages was not associated with the development of lymphoma, leukemia, or brain cancer.”

In March 2011, the U.K. Food Standards Agency’s Committee on Toxicity of Chemicals in Food (COT) reviewed the review the scientific evidence on possible effects of long–term, low-level exposure to methanol, and particularly the exposures that might occur from aspartame. The COT report stated that “from the evidence available, the COT concluded that amounts of methanol consumed through food, including from aspartame, would not result in build up of formate and so are unlikely to cause harmful health effects. “

In 2006, the U.S. National Cancer Institute examined data from over a half million retirees and concluded that “[i]ncreasing consumption of aspartame-containing beverages was not associated with the development of lymphoma, leukemia, or brain cancer. The authors of a 2013 independent review concluded, “With reference to epidemiologic data, evidence on low-calorie sweeteners – and specifically aspartame – does not support the existence of a consistent association with hematopoietic neoplasms, brain cancer, digestive sites, breast, prostate and several other neoplasms. The review also found aspartame and low-calorie sweetener use are not related to vascular events and preterm deliveries. (Marinovich et al., 2013)

Headaches: Most studies investigating a relationship between aspartame and headaches show no effect. However, results from some small studies have shown a positive connection between aspartame intake and headaches, suggesting a susceptible population subset, although there is no biological explanation. Inconsistent findings may be caused by lack of objective measurements for headache onset or duration.


Scientific Opinion on the re-evaluation of aspartame (E 951) as a food additive. EFSA Journal 2013;11(12):3496 [263 pp.]. (full-text)

European Food Safety Authority. 9 April 2013. FAQ on aspartame. Available at: (Accessed June 15, 2015)

EFSA explains the Safety of Aspartame. Available at: (Accessed June 15, 2015)

Marinovich M, et al. Aspartame, low-calorie sweeteners and disease: regulatory safety and epidemiological issues. Food Chem Toxicol. 2013;60:109-15. (full-text)

Magnuson BA, et al. Review of the regulation and safety assessment of food substances in various countries and jurisdictions. Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2013;30(7):1147-220. (full-text)

Statement of EFSA on the scientific evaluation of two studies related to the safety of artificial sweeteners. EFSA Journal 2011;9(2):2089. Available at ( Accessed June 15, 2015)
[Statement addresses:
Halldorsson TI, et al. Intake of artificially sweetened soft drinks and risk of preterm delivery: a prospective cohort study in 59,334 Danish pregnant women. Am J Clin Nutr. 2010;92: 626-633.
Soffritti M, et al. Aspartame administered in feed, beginning prenatally through life span, induces cancers of the liver and lung in male Swiss mice. Am J Indust Med. 2010;53:1197-1206.]

Food Standards Agency (U.K.). Committee on Toxicity opinion on methanol safety. 04 April 2011.

U.S. National Cancer Institute. Fact Sheet: Artificial Sweeteners and Cancer. Available at (accessed June 19, 2015)

U.S. Food and Drug Administration. April 20, 2007. FDA Statement on European Aspartame Study. (last accessed Dec 16, 2013)

Magnuson BA, et al. () Aspartame: a safety evaluation based on current use levels, regulations, and toxicological and epidemiological studies. Crit Rev Toxicol. 2007;37:629-727.

Lim U, et al. Consumption of aspartame-containing beverages and incidence of hematopoietic and brain malignancies. Cancer Epidemiol Biomarkers Prevent. 2006; 15(9):1654–1659.

More Information

EFSA explains the Safety of Aspartame (2013). Available at (Accessed June 15, 2015)

2013 Comprehensive Risk Assessment of Aspartame by EFSA Reaffirms Safety

What Health Professionals Need to Know About Aspartame

Q&A About Aspartame (EUFIC)