A way to slash your risk?

To see what effect vitamin C, vitamin E, and multivitamins had on liver cancer risk, researchers from the Shanghai Cancer Institute investigated the dietary and supplement intake habits of 132,837 people as part of the Shanghai Women's Health Study and the Shanghai Men's Health Study for an average of 11 and 6 years, respectively.

• During the follow-up period, 267 people developed liver cancer.
• Higher vitamin E intake from diet and supplements was associated with a significantly lower risk of liver cancer in men and women.
• Vitamin C and multivitamin supplements were associated with a higher risk of liver cancer in people with liver disease or a family history of liver cancer.
• Vitamin C and other vitamins from dietary sources didn't seem to affect liver cancer risk.

"We found a clear, inverse dose-response relation between vitamin E intake and liver cancer risk," the authors said.

Vitamin E is an antioxidant nutrient that can help prevent DNA damage and facilitate DNA repair, boost the immune system, and inhibit cancer formation. It's found in wheat germ oil, whole grains, nuts, seeds, egg yolks, and leafy green vegetables. In dietary supplements, the natural (and more absorbable) type of vitamin E is listed as the "d" form.

More research is needed

The results of the new study are encouraging, but need to be repeated in controlled trials. The study was observational, meaning that the investigators relied on people's reporting of their dietary and supplement intake habits to draw conclusions. In a controlled trial, the participants are randomly assigned the study substance or placebo. Conclusions drawn from observational studies are not as meaningful or reliable as those from controlled trials.

(J Natl Cancer Inst 2012;DOI:10.1093/jnci/djs277)