Is aspartame consumption bad for your health? It seems many people think so. What does the evidence say?

Aspartame and health

Aspartame is an artificial sweetener made up of phenylalanine and aspartic acid. The sweetener is marketed under a few trademark names, including Canderel, Equal and NutraSweet, and can be found in approximately 6000 products, including diet beverages, supplements, tabletop sweeteners, teas, and deserts. It isn't absorbed by the body and is completely broken down in the intestine, where it yields it’s constituent amino acids, phenylalanine and aspartic acid, and free methanol.

Anti-aspartame proponents claim free methanol and phenylalanine present health risks. They may be surprised to find out that the phenylalanine and methanol released from aspartame is small compared to the amount of these substances found in some other dietary sources. An aspartame sweetened drink contains 20 mgs of methanol, an equivalent serving of fruit juice produces 40 mgs, and an alcoholic beverage contains 60–100 mgs (1). A diet soda contains 100 mgs of phenylalanine compared with 300 mgs for an egg, 500 mgs for a glass of milk, and 900 mgs for a large hamburger.

Clinical studies have shown no evidence of toxic effects when aspartame is consumed in dosages of 50 mg/kg/d. This is equivalent to a 154-lb person drinking 17 cans of diet soda per day. From the American Council of Science and Health, “Numerous authorities, including the Food and Drug Administration, the Joint Expert Committee on Food Additives of the FAO/WHO, the European Community, and the American Medical Association have concluded that aspartame is a safe product, except in the rare cases of phenylketonuria.” Phenylketonuria is a rare inherited disease that prevents phenylalanine from being properly metabolized.

The FDA says aspartame is, “one of the most thoroughly tested and studied food additives the agency has ever approved.” Furthermore, “the more than 100 toxicological and clinical studies it has reviewed confirm that aspartame is safe for the general population” (3). The weight of existing scientific evidence indicates that aspartame is safe at current levels of consumption as a non-nutritive sweetener.

Aspartame and appetite

Some individuals in the fitness industry promote the claim that aspartame consumption increases appetite. A study conducted by Drewnowski and colleagues et al. (2) examined the effects of four breakfast preloads of different sweetness and energy content on motivational ratings, taste preferences, and energy intakes. The participants were 12 obese women and 12 lean women. The preloads consisted of creamy white cheese and were plain, sweetened with sucrose or aspartame, or sweetened with aspartame and supplemented with maltodextrin. However, energy intakes at lunch, snack, or dinner did not vary as a function of preload type, and no compensation was observed for the energy consumed at breakfast. Taste preferences weren't affected by preload ingestion or by preload type. The study provided no evidence that aspartame promotes hunger or results in increased energy intakes in obese or in lean individuals.

Anton et al. (2010) tested the effect of preloads containing stevia, aspartame, or sucrose on food intake, satiety, and postprandial glucose and insulin levels. Self-reported hunger and satiety levels did not differ by condition. Stevia preloads significantly reduced postprandial glucose levels compared to sucrose preloads and postprandial insulin levels compared to both aspartame and sucrose preloads. When consuming stevia and aspartame preloads, participants did not compensate by eating more at either their lunch or dinner meal and reported similar levels of satiety compared to when they consumed the higher calorie sucrose preload.

Epidemiological data have demonstrated an association between sugar substitutes and weight gain. However, there is a sparsity of evidence showing a causal relationship. The preponderance of evidence does not support the claims made by many in the fitness industry, "sugar substitutes will make you eat more." It is important to understand that appetite isn't the only thing that motivates food consumption. Many other factors drive us to eat when we aren't even really hungry.

References

  1. Hale J (2010) Nutrition: Fact or Fiction. PowerPoint presentation.
  2. Hale J (2011) Sugar substitutes and appetite. Retrieved on March 29, 2011. From: http://maxcondition.com/comment.php?comment.news.86.
  3. Henkel J (2004) Sugar Substitutes: Americans Opt for Sweeteners and Lite. U.S. Food and Drug Administration. Retrieved on March 29,2011. From: http://web.archive.org/web/20071214170430/www.fda.gov/fdac/features/1999/699_sugar.html.