CRN's Background Evaluation

Recent publicity made the following unfounded allegation: "Creatine, a dietary supplement used by many athletes to increase muscle bulk, could lead to cancer" (Reuters, 24 Jan 2001). The story was based on a report from a French government agency, the French Agency of Medical Security for Food (AFSSA). There are two parts of the report and they may be downloaded as follows:

Advice ( http://www.afssa.fr/ ), and the Report( http://www.afssa.fr/ ). The report is available only in French (an English version of the website is "under construction").

The Reuters article makes an issue of potential adverse effects and the ban of creatine by some athletic associations. The AFSSA discusses possible carcinogenic effects and asserts its opinion that use of creatine supplements is against the spirit of sportsmanship and fair competition.

The AFSSA report assertions of possible carcinogenic risk are based on three theoretical possibilities:

1. The first theoretical possibility is that creatine could be involved in formation of carcinogenic nitrosamines, under conditions of high concentrations of sugars and amino acids. These conditions do not apply to oral intakes of creatine, and thus allegations of "lack of safety" for oral creatine cannot be based on this issue.

2. The second possibility is the formation of carcinogenic heterocyclic amines from creatine during charbroiling (pyrolysis) of meats. This possibility is supported by a large body of scientific data, but is not relevant to oral creatine supplementation. It is directly relevant to the safety of charbroiled meats, but not to the safety of creatine used as a dietary supplement. Allegations of "lack of safety" for oral creatine cannot be based on this issue.

3. The third possibility is that creatine itself might be carcinogenic. The AFSSA report cites no studies of any kind to support such a possibility. In fact, there is no available evidence to support the possibility and there is a considerable body of evidence to the contrary. In opposition to a hypothesis that creatine might cause cancer, a strong body of scientific evidence suggests that creatine and some of its chemical analogs may have cancer inhibitory properties (Markus Wyss and Rima Kaddurah-Daouk, Creatine and Creatinine Metabolism,Physiological Reviews, 2000;80:1108-1213).

Experienced creatine researchers from three separate institutions have provided detailed information to support creatine safety:

1. Mark Tarnopolsky, MD, PhD, of McMaster University Medical Center (tarnopol@mcmaster.ca),
2. Drs. Markus Wyss and Rima Kaddurah-Daouk, of the Avicena Group (rima_daouk@avicenagroup.com), and
3. Prof. Theo Wallimann, of the Swiss Federal Institute of Technology Zurich (theo.wallimann@cell.biol.ethz.chand website http://www1.cell.biol.ethz.ch/).