Expert: Dr. Henry Boyter, Jr. - 3/5/2005

Question
Hello. I have been working on a research project entitled "Prevention of Cancer Through Antioxidants." For my project, I wanted to prove that antioxidants had the capability of preventing cancer. For my project, I used medaka fish eggs. I kept the fish eggs in different types of solutions. Some eggs were kept in just normal water. Another set of eggs were kept in water that had 1 mg of ascorbic acid (Vitamin C - the antioxidant) in it. Another set off eggs were kept in water that had 1 mg of urethane(a known carcinogen that causes cancer). And a final set of eggs were kept in water that had both Vitamin C AND urethane.
I monitored the development of the embryos inside the eggs (Because the eggs are clear). I expected that the urethane would cause the embryos to die or grow abnormally. I expected that the Vitmani C would cause the empryos to grow extra well, and I expected that the affect of the Vitamin C would cancel out the negative affect of the toxic urethane.
On the contrary, my results were totally different. All the eggs that were exposed to Vitamin C were dead after  about 5 days (both the eggs that were exposed to just vitamin C, and the eggs that were exposed to vitamin C and urethane). Also, the eggs that were kept in the solution that had just urethane grew perfectly normal. They developed basically the same way the eggs in plain water developed. I am very confused as to why this happened. Vitamin C, which is supposed to benefit organinsms, was deadly, But the known cancer-causing carcinogen had no effect. I would really appreciate it if you could share some insight on why this could have happened. Thank you.

Answer
Vitamin C above certain levels is acutely toxic. ALL CHEMICALS CAN BE TOXIC ABOVE CERTAIN LEVELS.  On the other hand cancer can take a long time to develop, 10-40 years for humans (a chronic effect).  I am not familiar with the eggs you used, but I think you have shown they are acutely sensitive (due to toxicity) to Vitamin C and that they either do not get cancer from this environment or you didn't wait long enough.  Carcinogens do not cause cancer in all species in all situations.