What Are the Symptoms of Aspartame Poisoning?

Aspartame is an artificial sweetener that is much sweeter than sugar but has fewer calories. It is used as a sugar substitute in many packaged foods and drinks. While it's considered safe to eat for most, some people need to be careful about how much they get in their diet.

Here's the breakdown on which foods contain aspartame as well as the causes and symptoms of aspartame poisoning.

Aspartame is about 200 times sweeter than sugar and is used to sweeten foods and drinks without adding sugar and calories to the nutrition facts, according to the International Food Information Council.

It can often be found in:

• Diet sodas
• Juices labeled "diet" or "low-sugar"
• Flavored waters
• "Light" flavored yogurt
• Flavored milk
• Sugar-free drink mixes, such as hot chocolate

• Some protein or nutrition bars
• Puddings or gelatins labeled "low-sugar" or "sugar-free"
• "Light" popsicles and ice cream
  
• Some breakfast cereals
• Some sauces, syrups and other condiments
• Chewing gum

• Equal
• Nutrasweet
• Sugar Twin
• Canderel
• Pal Sweet

• Chewable or gummy vitamins
• Cough drops
• Some prescription and over-the-counter medications

You can always check a food's ingredients list to see if it contains aspartame.

Aspartame is approved for use by the Food & Drug Administration (FDA), and there are more than 100 studies that support its safety for most people. However, people with phenylketonuria (PKU) need to be careful about their aspartame intake.

PKU is a rare genetic disease that makes it hard to digest the amino acid phenylalanine, per the Mayo Clinic. When a person with PKU gets too much phenylalanine in their diet, it can build up in their body, causing serious side effects. Because aspartame contains phenylalanine, getting too much when you have PKU could be called aspartame poisoning.

While some studies have linked aspartame to side effects not related to PKU, there's no evidence that aspartame poisoning is a concern for people without the disease.

The FDA says the acceptable daily intake (ADI) of aspartame is 50 mg per kilogram of body weight. A kilogram is equal to about 2.2 pounds, so using this math, a 132-pound person should be able to safely take in 3,000 mg of aspartame each day — that's about 75 packets of aspartame sweetener.

To add some perspective, the FDA estimates that if all of the added sugar eaten daily by that same 132-pound person were replaced by aspartame, they would be getting between 8 and 9 mg/kg each day — a far cry from the 50 mg/kg ADI.

For people with PKU, a buildup of phenylalanine in the body from too much aspartame or other sources may cause the following symptoms, according to the Mayo Clinic and Nemours:

• A musty odor in the urine, skin or breath
• Seizures and other neurological problems
• Eczema or other skin rash
• Hyperactivity
• Intellectual disability
• Growth problems and developmental delays
• Behavioral, emotional and social problems
• Psychiatric disorders

Some people without PKU claim to have an intolerance or sensitivity to aspartame that causes side effects like headache or digestive problems, but there's only anecdotal evidence to support this idea.

Only a few studies have been done in this area, all of which have been either small or designed poorly (or both), and they have come up with conflicting results. So, there doesn't seem to be any weight behind the idea that some people are sensitive to aspartame.