Does Diet Pop Cause Cancer?

First of all, I’m from Pittsburgh and we call it POP, not soda.

Second of all, the above question is a bit too broad. The question we should be asking is, “Does the artificial sweetener, aspartame, cause cancer”? Found in Diet Coke, Diet Pepsi, and Diet Mountain Dew, aspartame is one of the most common artificial sweeteners used in today’s food industry.

diet coke

What Is Aspartame?

Aspartame is also commonly known as NutraSweet or Equal. It is comprised of a methyl ester of aspartic acid and phenylalanine dipeptide. The majority of use for aspartame is in low-calorie, low-carbohydrate, sugar-free beverages. Gram for gram, aspartame has the same caloric content as sucrose (4 calories/gram). However, because aspartame is nearly 200 times sweeter than sucrose (table sugar), much less is needed in order to obtain the desired sweetness in foods and drinks. So much less, in fact, that companies can claim “zero calories” on food labels.

Physiologically, aspartame is digested by becoming hydrolyzed in the intestinal lumen by esterases and peptidases into aspartic acid, methanol, and phenylalanine, where these individual components are then absorbed into the general circulation. Aspartame is a white powder that is stable under dry conditions, but degrades in high temperatures.

aspartame chemical structure

Artificial sweeteners, such as aspartame, are regulated by the U.S. Food and Drug Administration (FDA). The FDA approved the use of aspartame for use in dry foods in 1981 and for general purposes in 1996. The first use of aspartame in carbonated beverages was in 1983. Today, aspartame can be found in more than 6,000 foods and pharmaceuticals worldwide.

What Products Contain Aspartame?

You may be surprised at the extensive and varied list of products that contain aspartame.

  • NutraSweet
  • Equal
  • diet or sugar-free soft carbonated soft drinks
  • breath mints
  • cereals
  • chewing gum
  • flavored syrups for coffee
  • flavored water
  • frozen ice cream novelties
  • fruit spreads
  • sugar-free gelatin
  • hard candies
  • ice cream toppings
  • no-sugar-added or sugar-free ice cream
  • iced tea
  • instant cocoa mix
  • jams and jellies
  • juice drinks
  • maple syrups
  • meal replacements
  • mousse
  • nutritional bars and drinks
  • puddings
  • sugar-free cookies
  • sugar-free ketchup
  • vegetable drinks
  • yogurt (drinkable, fat-free, sugar-free)

How Much Is Too Much?

The FDA has set an “acceptable daily intake”, or ADI, for each artificial sweetener. The ADI is set as the maximum amount considered safe for consumption each day during a person’s lifetime.

The U.S. ADI for aspartame is 50 mg per kg of body weight (mg/kg). The European Food Safety Authority has recommended a slightly lower ADI at 40 mg/kg.

To put this into perspective…

The average 12 oz can of diet pop contains 180 mg of aspartame.

For an average individual weighing 68 kg (or 150 pounds), the ADI level would be 3409 mg of aspartame

That is nearly 19 cans of diet pop per day!

It is safe to say that even the most avid diet beverage drinkers consume well below their ADI for aspartame. To prove this, diet soft drink consumption has increased over the past 20 years from 4.8 oz per person per day in 1984 to 5.5 oz per person per day in 2004 (see graph below). Nevertheless, the 5.5 oz is WELL below the FDA approved ADI for aspartame consumption.

diet drinks graph

Does Aspartame Increase the Risk for Cancers?

This is a question that has been debated for over the past 20 years. The overall consensus from most national health agencies is that, NO, there is no conclusive evidence that aspartame consumption increases the risk for cancer.

In a 100-page scientific review paper, the safety of aspartame was evaluated on several parameters. In regards to cancer, “There is no evidence to support an association between aspartame and brain or hematopoietic tumor development”. This extensive journal article reviewed both animal and human studies and found that most of the animal studies used aspartame levels well above the ADI, often in doses up to 4,000 mg/kg of body weight.

In a study published in 2012 in the American Journal for Clinical Nutrition, researchers prospectively evaluated and assessed the diets of >125,000 individuals over a 22-year period (from the Nurses Health Study and Health Professionals Follow-Up Study). Results found that, in men, >1 serving of diet soda increased the risk of non-Hodgkin lymphomas (RR: 1.31, 95% CI) and multiple myeloma (RR: 2.02, 95% CI) compared to men who reported no diet soda consumption. There was no significant difference found in women subjects. Interestingly, however, researchers also found a significantly greater risk of men (not women) developing non-Hodgkin lymphoma in subjects who consumed regular sugar-sweetened sodas. In summary, because of the differential effects on men vs. women and because of the apparent cancer risk in individuals who consume regular soda, it is difficult to interpret these results and put the full blame on aspartame as the cancer culprit.

In conclusion, the following are statements made by several national health agencies and associations regarding the consumption of aspartame and cancer:

  • The American Cancer Society states, “There are no health problems that have been consistently linked to aspartame use”.
  • The National Cancer Institute states, “There is no clear evidence that the artificial sweeteners available commercially in the United States are associated with cancer risk in humans”.
  • In a position paper by The Academy of Nutrition and Dietetics, “Studies have found no evidence of a wide range of adverse effects of aspartame, including hypersensitivity reactions, elevated blood methanol or formate levels, and hematopoietic or brain cancers”.
  • The FDA states, “The food additive aspartame may be safely used in food”.


Magnuson BA, et al. (2007). Aspartame: a safety evaluation based on current use levels, regulations, and toxicological and epidemiological studies. Crit Rev Toxicol. 37(8):629-727.

Schernhammer, et al. (2012). Consumption of artificial sweetener and sugar-containing soda and risk of lymphoma and leukemia in men and women. Am J Clin Nutr. 96(6):1419-28.