Once again, I’d like to thank everyone for their commentary, feedback, and questions regarding the two sweeteners I’ve recently written about: Splenda and Nectresse. Due to popular demand, I’ve decided to extend my series and focus this week on another standby, aspartame.
Aspartame is one of the older nonnutritive sweeteners, having been discovered in 1965. However, it has only been used in the US since the 1980’s. Sold under the brand names Equal and NutraSweet, It’s also one of the most commonly used sweeteners. Its patent expired in 1992, so generic versions of aspartame are now sold as well. This sweetener is made up of two amino acids, aspartic acid and phenylalanine. If you recall high school biology or chemistry, you’ll remember that amino acids are the building blocks of proteins. Amino acids are found naturally in many foods, including milk, meat, poultry, and beans.
Aspartame is about 200 times sweeter than regular sugar, and as you likely know, this sweetener is used in thousands of foods, candies, and beverages. It’s also used in some medicines and vitamins. One of the drawbacks of aspartame is that it’s not particularly heat stable, which means that it’s really not suitable for cooking or baking.
People who have a rare genetic condition called phenylketonuria (PKU) should not use aspartame or any product containing this sweetener. That’s because people with PKU can’t properly metabolize phenylalanine and levels of this amino acid can build up, causing intellectual disability and other serious health problems. PKU occurs in 1 in 10,000–15,000 newborns in the US, and most cases are detected shortly after birth.
Like other nonnutritive sweeteners, aspartame is regulated by the US Food and Drug Administration (FDA). This means that the FDA requires numerous studies showing its safety. In addition, the FDA has established an acceptable daily intake (ADI) for nonnutritive sweeteners, which is the maximum amount of a sweetener that can be safely consumed every day over the course of a person’s lifetime. The ADI for aspartame is 50 milligrams per kilograms (mg/kg) of body weight. So, for an adult weighing 75 kg (165 pounds), the ADI for aspartame would be 3,750 mg per day. To give you some perspective, a can of diet soda contains about 180 mg of aspartame; this person would need to drink 21 cans of diet soda every day to reach the ADI.
Aspartame is probably one of the most studied ingredients ever. More than 200 scientific studies have proven its safety. Nevertheless, much criticism and skepticism about this sweetener abounds. Countless Web sites on the Internet extol its danger; one Web site is named AspartameKills.com. Why is there such hype about this sweetener? According to many people (experts and nonexperts alike), aspartame causes the following issues (I’ll just list a few):
• Muscle spasms
• Heart palpitations
• Slurred speech
• Vision and hearing problems
• Brain tumors
• Memory loss
• Multiple sclerosis
In addition, aspartame is believed (by some) to worsen existing conditions, including the following:
• Alzheimer disease
• Multiple sclerosis
• Parkinson disease
Understandably, most people would probably pause and think twice about using a product that is supposedly the cause of the above symptoms and conditions. However, most of these claims are unproven or unfounded by clinical studies. Anecdotal reports are one thing (and by the way, if you believe that any food or product causes a particular symptom, it’s wise to avoid it), but there is little credible scientific evidence that aspartame causes any of the above.
Studies have been done investigating whether aspartame causes cancer. These studies are done with lab animals (and remember that results in rats and mice often do not apply to humans). An Italian study suggested that aspartame caused leukemia and lymphoma in rats; however, the results have been questioned by other researchers, so the study is inconclusive. As far as human studies, researchers look at the incidence of certain types of cancer in populations of people. Again, there is little evidence that aspartame is the cause of any type of cancer.
One of the concerns about using aspartame is that when it’s broken down in the body into its two amino acids, methanol is formed. Methanol, better known as wood alcohol, is a toxic compound. It’s used in paint thinner, antifreeze, and glass cleaners. Obviously, it’s disturbing to think that drinking a can of diet soda sweetened with aspartame is like drinking paint thinner. But that’s not the case. Methanol is found naturally in fruit and vegetable juices, whiskey, wine, and beer. A glass of tomato juice provides about six times more methanol than a beverage sweetened with aspartame. The liver is very well equipped to handle the amount of methanol that we consume from foods and beverages.
What does all of this mean for you? Hopefully by now you know that I don’t endorse products and that I believe the decision to use a product is an individual one. Assess your own degree of comfort with using aspartame (or any sweetener, for that matter). And keep in mind the practice of moderation: Drinking a can of diet soda here and there is likely no cause for alarm. But if you’re uncomfortable with that, avoidance is the safest bet!