Could cancer be linked to lifestyle?

New research in the cancer field indicates that genetics may not play as large a role in cancer risk as once thought. In fact, environmental factors may be a more important contributor to cancer risk than previously thought. Lichtenstein et al. (2000) conducted a study of 44, 788 twins in Finland, Denmark and Sweden to assess cancer risk. Results indicate that while genetics make a small contribution to susceptibility to most types of cancer, environment has a large role in causing cancer. Most types of cancer showed little impact of shared genes. Prostate cancer is one of the cancers with the highest genetic influence but studies have also shown a large environmental component. Rates of concordance were generally higher in monozygotic twins than dizygotic twins, but even for genetically identical twins, there was a less than 15% chance of developing the same cancer.

The authors acknowledge that this study does not take into account specific types and degrees of exposure to environmental risks, such as tobacco use or diet, so issues of gene and environment interaction cannot be fully explored. But they also mention that despite it's limitations, the Lichtenstein et al. study provides "new and valuable information for the nature-versus-nurture debate."

Due to the influence of environment on cancer risk, diet can either reduce or exacerbate a genetic predisposition. There is evidence that a diet high in fruit and vegetables can protect against lung and possibly breast cancer, and a diet that includes plenty of vegetables protects against bowel cancer. On the other hand, diets high in red meat and alcohol may increase bowel cancer risk. Breast cancer risk may also be increased with alcohol consumption, and possibly red meat. Products thought to protect against cancer include fish (due to omega-3 fatty acids or other unknown components), green and oolong tea, and soy based products.

References

Lichtenstein, P., Holm, N.V., Verkasalo, P.K., Iliadou, A., Kaprio, J., Koskenvuo, M., Pukkala, E., Skytthe, A., Hemminki, K. Environmental and Heritable Factors in the Causation of Cancer - Analysis of Cohorts of Twins from Sweden, Denmark and Finland. NEJM. July 13, 2000. Vol343, No. 2.

Hoover, R.N. Cancer - Nature, Nurture or Both. NEJM. July 13, 2000. Vol. 343, No 2.

Better Health Channel - Cancer and Food.

Last Updated: April 5, 2001.