Aspartame is a popular sugar substitute found in diet sodas, snacks, yogurts, and other foods. Since its approval by the Food and Drug Administration (FDA), the sweetener has been plagued with controversy from certain parts of popular culture and scientific communities. Some are concerned that aspartame poisoning can lead to health problems like multiple sclerosis (MS) and lupus.

Is it really possible that an artificial sweetener approved by the FDA could be that dangerous?

Aspartame is a manmade substance. It is a combination of two ingredients:

1. Aspartic acid. This is a nonessential amino acid naturally found in the human body and in sugar cane. (Amino acids are the building blocks of protein in the body.) The body uses aspartic acid to create hormones and to support normal function of the nervous system. Other sources include beans, nuts, seeds, beef, eggs, and salmon.

2. Phenylalanine. This is an essential amino acid found naturally in the breast milk of mammals, but it’s not naturally produced in the body. Humans have to get it from food. The body uses it to make proteins, brain chemicals, and hormones. Sources include lean meats, dairy products, nuts, and seeds.

When these two ingredients are combined, they create a product that is about 200 times as sweet as regular sugar. That means manufacturers can use very little to make a product taste sweet. The result is a food that tastes good but delivers very few calories.

A number of websites claim that aspartame (also sold as Equal and NutraSweet) causes a lot of health problems, including:

  • MS
  • lupus
  • seizures
  • fibromyalgia
  • depression
  • memory loss
  • vision problems
  • confusion

The FDA approved aspartame as a nutritive sweetener in 1981 and for use in carbonated beverages in 1983. At the time, some scientists objected to the approval. They were concerned about an animal study that showed the amino acids might cause mental retardation, brain damage, and potential brain tumors.

A safety board decided that humans would likely never consume the extremely high amount of aspartame that had been linked to potential health problems. They added that the animal study was flawed, and that the sweetener was safe.

The FDA’s website states that over 100 studies support the safety of aspartame. The American Cancer Society adds that the FDA has set an “acceptable daily intake (ADI)” for the ingredient. This is about 100 times less than the smallest amount that was found to cause health concerns in animal studies.

What have we found since the 1980s? For the best information, we turn to scientific studies. Here’s some of what we’ve discovered so far:

Phenylketonuria (PKU)

People with this rare genetic condition can’t properly metabolize phenylalanine, one of the ingredients in aspartame. For that reason, they should avoid the sweetener. If they ingest it, it builds up in the body. Without treatment, it can cause brain damage.


Some animal studies found a link between aspartame and leukemia and other blood cancers. A 2007 study, for example, found that rats given low doses of aspartame every day of their lives, including fetal exposure, were more likely to develop cancer.

A 2012 study found that more than one daily serving of diet soda increased risk of non-Hodgkin’s lymphoma in men. But the study also found an increased risk for non-Hodgkin’s lymphoma in men who consumed high amounts of regular soda. Scientists couldn’t say for sure if it was aspartame or something else causing the risk. It is imperative to note that the same scientists later issued an apology for the study. They stated the data from the study was weak.

According to the American Cancer Society, a large study of over 500,000 adults found no connection between aspartame and increased risk of lymphomas, leukemias, or brain tumors.

Multiple Sclerosis

According to the National MS Society, no studies support a link between aspartame and MS.


The Lupus Foundation of America states that, so far, there is limited scientific research on aspartame and Lupus. Past studies have shown conflicting results. So far, there is no reliable scientific evidence that aspartame increases the risk for Lupus.


Does aspartame increase risk of headaches? A 1987 study reported on the issue. Researchers found that people taking aspartame didn’t report any more headaches than those who took a placebo.

However, a small 1994 study found different results. Researchers suggested that some people may be susceptible to headaches from aspartame. This study was later criticized because of its design.


In a 1995 study, researchers tested 18 people who said they experienced seizures after consuming aspartame. They found that even with a high dose of about 50 mg, aspartame was no more likely to cause seizures than a placebo.

An earlier 1992 study on epileptic and nonepileptic animals found similar results. A report by the European Food Safety Authority stated that the vast majority of studies looking into the issue have found no link between aspartame and seizures.


In 2010, scientists published a small case study report about two patients and the adverse effect of aspartame. Both patients experienced relief from fibromyalgia pain by removing aspartame from their diets.

A later study of 72 female patients found no evidence to support a connection. Removing aspartame from the participants’ diets had no effect on their fibromyalgia pain.

Mood Changes

Could aspartame increase risk of mood disorders like depression? In one study, scientists compared those with and without a history of mood disorders. They found that aspartame did seem to increase symptoms in patients with a history of depression. It had no impact in patients without such a history.

A 2014 study of healthy adults found similar results. When participants consumed a high-aspartame diet, they suffered from more irritability and depression.

The list above cites only a few of the studies published on aspartame and health conditions. In most cases, besides potentially being linked with mood disorders, aspartame had no connection to seizures, MS, lupus, or other illnesses.

The following organizations all agree that aspartame is a safe sugar substitute:

  • FDA
  • Joint Expert Committee on Food Additives
  • United Nations Food & Agriculture Organization
  • European Food Safety Authority
  • World Health Organization

None of these organizations put any credence into the idea of “aspartame poisoning.”

Because of increased public concern, however, more food and drink manufacturers have chosen to avoid aspartame. If you think you may be sensitive to it, you can easily avoid it by reading labels and choosing aspartame-free products.