Debunking Myths on Aspartame, Part I

Young woman is listening at the conference

By Rosanne Rust MS, RDN, LDN  —

Aspartame is a non-nutritive sweetener made of two amino acids (phenylalanine and aspartic acid) and methanol. As it is 200 times sweeter than sugar, only tiny amounts of aspartame are needed to achieve the desired sweetness, reducing the number of calories compared with sugar. When consumed, it’s completely metabolized into these components, which are common in many other foods (or instance, an 8-ounce glass of milk contains about seven times the phenylalanine as a serving of 8 ounces of a beverage sweetened with aspartame). It was discovered in 1965, and its metabolism is well understood which is why the Food and Drug Administration (FDA) approved it for use as a sweetener in 1981. Aspartame is used in low calorie foods such as chewing gum, beverages, yogurt, frozen desserts, powdered drink mixes, cough drops, and table-top sweeteners.

Before a food additive is approved, regulatory bodies, such as the FDA, insist on seeing scientific evidence that the additive is safe. They use a measurement called “Acceptable Daily Intake (ADI)” to put into context amounts that would cause no adverse side effects. The ADI is expressed in milligram (of additive) per kilogram of body weight. The ADI for aspartame is 50 (equivalent to 22 cans of diet soda for a 175 person or 6 cans for a 50 pound child). Market research has shown that typical consumption is below that.

Even though hundreds of research studies have shown no human health risk for aspartame, several myths circulate about this sweetener.

MYTH: Aspartame increases Risk of Cancer

FACTS: The National Cancer Institute  states that aspartame does not cause cancer. Aspartame doesn’t enter the bloodstream and can’t reach essential organs. One study that receives undue attention from the Ramazzini Institute has been widely criticized by many regulatory bodies and leading experts in the field of toxicology. These rat studies were poorly controlled and poorly designed. For instance, many of the rats were already sick with a chronic respiratory disease, which just so happens increase the risk of the same kinds of cancer that Ramazzini attributed to aspartame. As with many studies that correlate a food ingredient to cancer, the amounts delivered to the rats were in massive quantities, completely without correlation to human consumption. However even the long-term rodent studies using large doses (equal to the amount of aspartame in more than 1,000 cans of diet soft drink daily over a lifetime) done prior to its 1981 FDA approval, still found no increase in tumors.

MYTH: Aspartame causes diabetes or affects glucose intolerance

FACTS: Aspartame has been reviewed and determined safe by the FDA and the American Diabetes Association and American Heart Association have issued a joint statement on the use of non-nutritive sweeteners. Studies have demonstrated no effect on glycemia or appetite with normal consumption of aspartame.

MYTH: Aspartame causes weight gain.

FACTS: Changes in body fat are related to many factors including overall calorie intake, exercise, genetics and age. A number of studies have shown aspartame does not increase weight or impact sugar cravings. In fact products sweetened with aspartame can replace high calorie products sweetened with sugar, thereby creating a calorie deficit, which ultimately results in weight loss. The myth that aspartame or other sweeteners may “increase sugar cravings” is not substantiated by evidence.

MYTH: Aspartame increases heart disease risk

FACTS: There are many controllable risk factors for heart disease: obesity, diet, exercise, stress level, and whether or not you smoke (heredity and gender are uncontrollable risk factors). Diet and exercise can help control blood pressure and diabetes risk (both heart disease risk factors). There are however no well-designed studies that can conclude that consuming foods or beverages with aspartame increases your risk for heart disease. One study concluded “an association” with drinking diet beverages and heart disease, but this does not prove aspartame was the risk factor. The study, which reviewed the diet of post-menopausal women (menopause itself can cause metabolic changes in a woman, which naturally increase her risk for heart disease), did not control for other risk factors (body weight, diet, exercise), it only reviewed how many diet beverages the women drank and made a conclusion about this association. Even the study’s authors admit to limitations.

Limitations of this study include its observational nature, and the fact that it involved retrospective analysis of data not collected expressly for the purpose of this paper. It also involves a specific population, that of post-menopausal women, and thus may not be generalizable to other populations. 

When reviewing the literature and popular press about non-nutritive sweeteners like aspartame or other food ingredients, it’s important to closely read the actual studies that are referenced. Correlation does not equal causation, and humans can’t be implicitly compared to rodents. Almost anything can be toxic (including common ingredients such as potassium, sodium or water) if given in excessive dosages, as often the case in rat studies.

Typical use of products containing aspartame is safe, and they can be enjoyed within a balanced diet. The use of diet beverages or foods such as yogurt, can support anyone’s weight loss plan and diet adherence for those with diabetes. Enjoying a diet beverage as part of a healthy lifestyle is not a risk factor. The most effective diet and lifestyle modification involves making changes proven to be effective for wellness: regular physical activity and a diet that includes more vegetables, fruit, nuts, seeds, monounsaturated oils, and whole grains.



Rosanne Rust MS, RDN, LDN is a registered, licensed dietitian-nutritionist with over 25 years experience. Rosanne is a paid contributor for the Calorie Control Council. As a Nutrition Communications Consultant  she delivers clear messages helping you understand the science of nutrition so you can enjoy eating for better health. Rosanne is the co-author of several books, including DASH Diet For Dummies® and the The Glycemic Index Cookbook For Dummies®. A wife, and mother of 3 boys, she practices what she preaches, enjoying regular exercise, good food and festive entertaining. Follow her on Twitter @RustNutrition.

Items of Interest

August 15, 2018 Claims & Myths, Professional Research, Research Summaries