What Is Aspartame?

What Is Aspartame?

Aspartame is an artificial sweetener whose presence in our food supply has been clouded with controversy. It’s 200 times sweeter than sugar and is most commonly used in diet drinks and foods under the brand names NutraSweet and Equal. Despite its prevalence and its FDA approval in 1981, the sweetener has been plagued by real health effects, rumors and many misunderstandings.

Artificial sweeteners like aspartame are found in a variety of foods marketed for weight control. Diet sodas are a major source of aspartame, but it is also found in other foods labeled as “sugar-free,” including yogurts, drink mixes, flavored waters, condiments and chewing gum.

A history of aspartame

A chemist named James M. Schlatter discovered aspartame in 1965 while working on an anti-ulcer drug for G.D. Searle & Co. He was in the lab when a solution got on his hand. Later, as he went to pick up a piece of paper, he licked his finger and found a super-sweet flavor. The effect, he would determine, is caused by two amino acids—phenylalanine and aspartic acid—compounds that in isolation taste bitter and slightly sour, but together produce this sweetness. These amino acids, incidentally, are found naturally in many foods.

In the decades following Schlatter’s discovery, Searle faced criticism of its new product. Beginning with a 1975 task force assembled by the U.S. Food & Drug Administration, the research backing aspartame’s safety was called into question. Analyzing a series of studies submitted by Searle, the panel found serious shortcomings in the company’s operations and practices, but ultimately said these deficiencies didn’t necessarily negate the research.

How much aspartame is safe?

The FDA has set the acceptable daily intake of aspartame at 50 milligrams per kilogram of body weight. For an average man weighing 165 lbs., this would be the equivalent of 3,750 milligrams—or 19 cans of diet soda each day.

On the extreme chance someone were to drink 20 cans, or otherwise go over the limit, the FDA says he likely wouldn’t experience ill effects, as they set the limit to be 100 times less than the smallest amount that could cause health problems, according to the American Cancer Society.

Does aspartame cause cancer?

Many of the concerns about aspartame center on its alleged cancer link. So, does the sweetener cause cancer?

There are two ways of testing the aspartame-cancer connection: in animals and in humans. While both methods provide good information, neither type of study has provided proof one way or the other, so conclusions must often be based off a collection of evidence.

Most scientific studies in humans have found no link between aspartame and cancer. Though a few have indicated a possible connection, the conventional belief is that these studies were flawed in one way or another.

For instance, research led by Dr. Morando Soffritti of the Ramazzini Foundation in Bologna, Italy did find higher rates of leukemia, lymphomas and other cancers in rats fed very high doses of aspartame in 2005. This work is widely cited, but has also been criticized for administering aspartame at rates no human would likely ingest. Also, the FDA said the evidence was not significant enough to alter their conclusion that aspartame is safe.

The largest study of the issue, from the National Cancer Institute, analyzed data from nearly 500,000 people and found no increased risk of lymphoma, leukemia or brain cancer with increased aspartame consumption.

Still, aspartame faces criticism. As the Center for Science in the Public Interest reports, many studies on the harmless effects of the sweetener are supported by companies who stand to make money off of the aspartame industry. The CSPI says studies like those from the Ramazzini Foundation in Italy “should be reason enough” for the FDA to ban aspartame, and the organization suggests people avoid it altogether.

Is aspartame bad for you?

For some, sensitivity to the sweetener could cause increased risk of headaches or nausea, commonly referred to as aspartame toxicity. People have blamed symptoms such as seizures, dizziness, depression, irritability, heart palpitations, breathing problems, anxiety and even death on aspartame toxicity, but many, including the FDA, say there is little hard evidence linking the symptoms directly to the sweetener. Still, food sensitivities are real and hundreds of people have reported such aspartame toxicity symptoms over the years. People who experience health problems after consuming aspartame may have reason to steer clear, whether their symptoms are given a concrete medical diagnosis or not.

The FDA does recognize the possible dangers aspartame poses to small segments of the population. People who suffer from a genetic disease known as phenylketonuria, pregnant women with high levels of phenylalanine in their blood and people with advanced liver disease all have difficulty metabolizing phenylalanine, an amino acid found in aspartame. For them, the resulting high levels of phenylalanine could result in brain damage.

Are there side effects of aspartame?

Though aspartame is frequently used in weight-control efforts, there is evidence that it and other sugar substitutes can actually be addictive, increase body weight and lead to more intense food cravings.

The American Psychological Association defines addiction as a condition where a person must have a drug to avoid symptoms of withdrawal, either physical or psychological. In one analysis, H.J. Roberts, M.D., found 33 of 540 study participants to suffer from withdrawal symptoms upon ceasing consumption of aspartame. These 33 patients were consuming massive amounts of aspartame—up to 12 cans of soda or 20 packets of sweetener a day. Their symptoms included irritability, tension, nausea, tremors, sweating and extreme cravings during the withdrawal stages.

A paper published in the journal Neuroscience suggests this aspartame addiction is possible because artificial sweeteners like aspartame do not affect the reward pathways of the brain in the way sugar does. We have an inherent craving for sweetness, the research says, that simply isn’t satisfied with aspartame. This fuels further cravings and “food seeking behavior,” which in turn can lead to weight gain. Also, because it is many times sweeter than sugar, aspartame essentially trains our brain to prefer sweeter foods.

Are there alternatives to aspartame?

Whether you are convinced by some of the existing scientific evidence or you feel you might have an aspartame sensitivity, there are alternatives.

  • Stevia leaf extract is one of the latest, natural alternatives to sugar. It is derived from the stevia plant and, like aspartame, is about 200 times sweeter than sugar. Though it is relatively new and little research has been done, it’s widely accepted as safe.
  • Sugar alcohols, including the most popular forms sorbitol and xylitol, may cause gastrointestinal stress, but are considered safe. These have neither sugar nor alcohol, and contain about half the calories of sugar.
  • Sucralose, sold under the brand name Splenda, has become popular in recent years. But the same research lab in Italy responsible for the aspartame cancer studies indicated a possible link between sucralose and leukemia, causing the CSPI to downgrade their rating of the sweetener from “safe” to “caution.”
  • Going without may seem too lofty a goal for many people with a sweet tooth or concerns about sugar, which is higher-calorie and affects blood glucose. But if you are able to eliminate the need for these additional ingredients in your drinks and foods, the conflicting information on their safety is no longer a concern for you.

There are few simple answers concerning the safety of aspartame. But it is used in more than 90 countries and in more than 6,000 products, indicating that regulators worldwide maintain its safety. For your health, the decision to indulge in the sweet stuff should be made after careful consideration of the evidence and effects.


Diet soda image via Shutterstock.

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