What’s the Buzz

What is Aspartame? 

Aspartame is an artificial sweetener and sugar substitute. Researchers discovered it in the 1960s, but large-scale production and human consumption of aspartame did not begin in the United States in the 1980s. 

Aspartame is available as a tabletop sweetener (brand names: Equal and Nutrasweet) and as a food additive. It is sometimes preferred over refined sugar (sucrose) because a small amount of aspartame can give the same sweetness as sugar. However, consuming aspartame has been potentially linked to health risks. 

Chemical Structure of Aspartame 

Aspartame is made of two amino acids: phenylalanine and aspartic acid. It is digested in the human gastrointestinal tract into three substances, phenylalanine, aspartic acid, and methanol, which are absorbed into the bloodstream. Researchers have found that these byproducts of aspartame metabolism are more toxic than aspartame itself and can be harmful at high doses. Therefore, prolonged or high-dose consumption of aspartame can be dangerous.

How Aspartame Compares with Sugar

Aspartame contains 4 calories per gram, the same as sugar. However, because aspartame is about 200 times sweeter than sugar, a much smaller amount can be used to achieve the same sweetness as sugar. Aspartame can be useful if you are trying to reduce your calorie intake from sugar.

Aspartame's taste and flavor differ from sugar’s. It also has an aftertaste that some people find unpalatable.

Aspartame is decomposed by heat and is not recommended for cooking and baking.

Uses of Aspartame in Human Food Supply

Aspartame is widely used in thousands of food products as a tabletop sugar substitute and artificial sweetener. 

It is frequently present in foods and beverages labeled as “low-sugar” or “sugar-free,” including diet sodas and other low-calorie beverages. In addition to soft drinks, aspartame is also present in sugar-free or low-calorie cold breakfast cereals, dairy products such as flavored yogurts, milks, ice creams, popsicles, puddings, salad dressings, ready-mixes, and more. 

Additionally, aspartame is present in some toothpaste, chewing gums, chewable vitamins, multivitamins, sugar-free cough drops, and other over-the-counter medicines and prescription drugs.

Aspartame Consumption: Acceptable Daily Intake

The U.S. Food and Drug Administration (FDA) regulates aspartame and other artificial sweeteners for safety. The FDA has set an acceptable daily intake (ADI) for aspartame of 50 milligrams per kilogram of body weight per day (mg/kg/day), the maximum amount of aspartame a person can safely consume daily. 

Other international and European authorities have set a lower ADI for aspartame of 40 mg/kg/day.

For example, if you weigh 70 kg (154 lbs), the amount of aspartame you could consume in a day is 3500 mg. Therefore, you would have to drink 10-15 cans of diet soda, each containing 200-300 mg of aspartame, to reach or exceed 50 mg/kg/day. 

Note: The Calorie Control Council says more than 6,000 products contain aspartame. Therefore, there is a risk that you may unintentionally consume larger amounts than the daily intake of FDA-approved aspartame. 

Health Concerns and Scientific Debate

Phenylketonuria (PKU)

Phenylketonuria is a rare genetic disorder in which a person has low levels of an enzyme that converts the amino acid phenylalanine to tyrosine. As mentioned, aspartame is broken down into phenylalanine in the body. In people with phenylketonuria, aspartame consumption can lead to a buildup of phenylalanine in the body, which can affect the dermatologic, reproductive, and nervous systems. 

High levels of phenylalanine can cause adverse effects such as eczema, skin and hair discoloration, small head size, cognitive dysfunction, behavioral problems, intellectual disabilities, and developmental delay. 

Aspartame consumption is a major concern in pregnant women who have phenylketonuria. The baby’s brain and heart are particularly vulnerable to high maternal phenylalanine concentrations. 

Cancer Risk

Some scientific evidence has pointed to links between aspartame and cancer risk, including blood cancers and liver cancer. However, the results of various studies are not consistent. The overall conclusion is that there are no major safety concerns at regular doses of aspartame. Nonetheless, researchers continue to conduct further studies to understand the potential links between aspartame and cancer.

Body Weight and Obesity

No-calorie sweeteners such as aspartame are marketed as a healthy alternative to sugar, especially for overweight or obese individuals who are trying to lose weight. However, scientific evidence does not fully support this claim. 

Replacing sugar-sweetened foods and beverages with artificial sweeteners can actually increase consumption, according to the results of some studies. Researchers believe this is because people tend to compensate for the calorie deficit from artificial sweeteners by eating excess calories from other food sources. 

Limited evidence also exists related to the flavor of artificially sweetened drinks, which can increase hunger and lead to weight gain. Overall, the effect of aspartame on body weight, obesity, and metabolic health needs to be further investigated. 

Type 2 Diabetes and Metabolic Syndrome

The link between non-nutritive sweeteners such as aspartame and type 2 diabetes mellitus remains unclear. In other words, we don’t know for sure whether sugar substitutes have a favorable or harmful effect on diabetes. Some studies have actually suggested that aspartame may cause type 2 diabetes due to an increase in pro-inflammatory markers. However, these data are not strong, and more randomized controlled trials are needed to understand these links better.

Pregnancy and Lactation

Some studies suggest that consumption of aspartame during pregnancy could result in preterm delivery and allergic conditions in the baby. However, no such link has been confirmed. Low-calorie sweeteners are considered safe to consume during pregnancy and lactation as long as the recommended daily levels are not exceeded.

Neurological and Behavioral Disorders

Aspartame has been suspected to contribute to neurological disorders such as headaches, depression, and convulsions. It is theorized that the breakdown products of aspartame— phenylalanine and aspartate— can affect the levels of neurotransmitters in the brain that regulate mood and behavior. 

Studies also suggest that aspartame consumption can increase the risk of neurodegenerative disorders such as Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, and brain tumors. This effect has been linked to the aspartame metabolite methanol, which can form free radicals and cause oxidative damage to brain cells. However, further research is needed to understand these adverse reactions.

Autism Spectrum Disorder

The significant increase in autism in the 1980s coincided with the rise in the consumption of aspartame in diet sodas and has continued to do so, suggesting a possible link. Studies have shown that autism is more frequent in children whose mothers were obese or had diabetes and who had higher aspartame consumption.

Skin Problems and Allergies

Researchers have not found a link between aspartame consumption and allergic reactions such as urticaria (hives) or angioedema (swelling). However, some studies suggest that aspartame may cause skin problems such as contact dermatitis (inflammation). 

Positions of Leading Organizations on Aspartame Safety

World Health Organization (WHO) 

International Agency for Research on Cancer (IARC)

The IARC is the WHO’s cancer research agency. They use “strength of evidence” to group carcinogenic (cancer-causing) substances as follows:

• Group 1: Carcinogenic to humans

• Group 2A: Probably carcinogenic to humans

• Group 2B: Possibly carcinogenic to humans

• Group 3: Not classifiable regarding carcinogenicity in humans

Aspartame has been classified as group 2B or “possibly carcinogenic to humans” by the IARC.

Joint FAO/WHO Expert Committee on Food Additives (JECFA)

JECFA is an international committee of experts run jointly by WHO and the Food and Agriculture Organization (FAO). They say that the evidence supporting links between aspartame consumption and cancer risk in humans is not convincing. JECFA believes that aspartame is not a health concern based on the current estimated dietary exposures.

U.S. Food and Drug Administration (FDA) 

The FDA has concluded that based on scientific evidence, aspartame is safe for consumption by the general population, provided it is manufactured using approved practices and used under approved conditions.

European Food Safety Authority (EFSA)

EFSA says that based on its risk assessment, aspartame, and its breakdown products are safe for human consumption at the current estimated levels of exposure.

Controversies and Bans: Aspartame in the Spotlight

Why the FDA Reviewed Aspartame’s Safety

The FDA reviewed aspartame’s safety after the IARC labeled it as “possibly carcinogenic to humans” in 2023. However, the FDA disagrees with the IARC's conclusion. The FDA’s review found significant shortcomings in the studies that IARC relied on to reach this conclusion. Notably, another WHO agency, JECFA, did not raise safety concerns about aspartame at the current levels of exposure and did not change the ADI.

Misconceptions and Myths About Food Additives

Common misconceptions and myths about food additives and sugar substitutes such as aspartame include:

• They trigger cravings

• They make you gain weight

• They cause insulin resistance

• They turn good bacteria in the gut into bad bacteria

The truth is that the U.S. FDA has found aspartame to be safe for human consumption. You can, therefore, use it instead of sugar if you are trying to eat a reduced-calorie diet and lose weight. Artificial sweeteners also generally do not raise blood sugar levels and may be a good choice if you have prediabetes or diabetes.

Aspartame Alternatives

The U.S. Food and Drug Administration (FDA) has approved six non-nutritive sweeteners, including aspartame. You can choose from the following low-calorie sweeteners based on your personal preferences:

• Aspartame (Nutrasweet, Equal)

• Acesulfame potassium (Sunett, Sweet One)

• Sucralose (Splenda)

• Saccharin (Sweet’N Low, Necta Sweet, Sweet Twin)

• Advantame (Advantame)

• Neotame (Newtame)

Note: Neotame and advantame are made from aspartame but are considerably sweeter. Compared to aspartame (which is 200 times sweeter than sugar), neotame is approximately 13,000 times sweeter, and advantame is 20,000 times sweeter than sugar.

If you don’t want to consume artificial sweeteners, you can consider eating foods that are natural sweeteners, such as maple syrup, honey, dates, agave nectar, and molasses.

Common Questions About Aspartame

Is aspartame really that bad for you?

No, aspartame is not really bad for you, provided you don’t exceed the ADI of 50 mg/kg/day.

What's worse: Sugar or aspartame?

Sugar is worse than aspartame in terms of calories for sweetness. While sugar and aspartame both contain 4 calories per gram, aspartame is 200 times sweeter than sugar. As a result, you only need a very small amount of aspartame to get the same sweetness as sugar. 

Why did the FDA ban aspartame?

The FDA did not ban aspartame. The FDA has said aspartame is safe for human consumption as long as one does not exceed the ADI of 50 mg/kg/day.

Why is aspartame banned in Europe?

Aspartame is not banned in Europe. However, the European Food Safety Authority (EFSA) and Joint FAO/WHO Expert Committee on Food Additives (JECFA)

recommend a lower acceptable daily intake (ADI) for aspartame at 40 mg/kg/day compared to the U.S. Food and Drug Administration (FDA), which recommends an ADI of 50 mg/kg/day.