Does the artificial sweetener aspartame cause cancer?

Aspartame is a synthetic, nonnutritive sweetener. In 1981, the United States Food and Drug Administration FDA approved it for use in dry foods, and approval was extended in 1983 to include carbonated soft drinks. Since then, aspartame and other artificial sweetenershave remained the subject of many different debates about their safety and potential benefits.

The focus of these debates is whether aspartame use causes cancer.

What happens after aspartame enters the body?

Aspartame taken orally as a sweetener is converted in the gastrointestinal tract into aspartic acid, phenylalanine and methanol. Methanol, one of these components, is converted first into formaldehyde and then into formic acid. Formaldehyde is one of the substances known to be carcinogenic in its effects.

The European Carcinogenicity Study on Aspartame and the FDA Statement

A long-term carcinogenicity study of aspartame was initiated in rats in Europe. Experimental cancer was induced in these rats; half were given aspartame daily at doses proportional to their weight and similar to those in humans, while the other half served as controls. Consumption began within 8 weeks and continued throughout their natural lifespans. All animals underwent a complete autopsy after death.

The last mouse died in week 159. There was no difference in overall survival between males and females among the animals given aspartame. The study concluded that tumor sizes in mice given aspartame were significantly larger than in the control group.

FDA reviewed the data in this study and requested additional data for a more detailed examination, but could access only part of the study data despite that request. The research team did not allow FDAto review the pathology blocks. Therefore, FDAdecided that the results of this study were not sufficiently reliable.

Aspartame and cancer risk in population-based epidemiological studies

A case-control study conducted between 1984-1991 in patients with brain cancer or healthy patients found no association between the artificial sweetener aspartame and brain cancer.

Another study reviewed dietary questionnaires from people aged 50-71, totaling 473.984 participants. It found no effect of aspartame consumption on cancer risk. However, those consuming approximately 200 mg of aspartame daily more often had a history of diabetes and higher body mass indexes. These results were interpreted as showing that people already diabetic or obese used more aspartame, rather than aspartame causing diabetes or obesity.

A study conducted in Italy between 1991 and 2004 found no association between aspartame use and cancers of the head and neck, esophagus, colon, rectum, breast, ovaries, prostate or kidneys.

Another study involving 125 thousand people found that consumption of aspartame-containing (diet) carbonated drinks increased the risk of non-Hodgkin lymphoma and multiple myeloma in men by approximately 1.3 and 2 times, respectively. It increased leukemia risk by 1.4 times in both sexes. It was also noted that risk was greater among those consuming more aspartame-containing diet carbonated drinks. The greater increase in risk in men was attributed to greater activity in men of the enzyme alcohol dehydrogenase type-1, which converts methanol into formaldehyde.

To confirm the results of this striking study, the Cancer Prevention Study-II Nutrition Cohort followed 100.442 people for 10 years. It found that aspartame consumption did not increase the risk of any blood and bone marrow (hematological) cancers, including non-Hodgkin lymphoma.

Conclusion

Many studies have shown that there is no significant association between consumption of the artificial sweetener aspartame and different cancers.

However, a recent study showed that using sweeteners instead of sugar does not help with weight loss, as reported in this study and demonstrated by its findings.