Perhaps most important of all are those studies that examine all the anti oxidants working in tandem. In a way, the Chinese results, where only the group with the highest number of antioxidants had improved cancer survival, suggests that antioxidant nutrients rely on an interaction with each other to produce the best results.
Although much of the laboratory and clinical evidence is spectacular, some of the studies that have been done to treat human cancer patients with nutrients have been small or inconclusive. In a companion trial done in the same province of China on 3000 people with esophageal cancer there was no significant survival difference between the group given 26 vitamins and those given a placebo. Again, this may be because treatment requires megadoses, and the study group was only receiving two or three times the RDA. While epidemiologic evidence consistently shows that people eating lots of fresh fruit and vegetables reduce their risks of cancer by as much as a half (Epidemiology, Cancer Causes Control 2:325-57, 1991), we still have much to learn about the dosage in treating people once they have the disease.
Sandra Goodman, Ph.D. has compiled the Nutrition and Cancer Database for the Bristol Cancer Help Centre which laypersons and professionals may contact on (0272) 743216.