Cancer and Nutrition
After taking MBP Oncology course and learning about cancer survival rates and recurrences, I realized that there is pretty much no effective treatment for cancer (I guess I had a very naïve view of this disease for a scientist). I study replication of DNA, so most of the reagents that I am using are potential carcinogens. Also, throughout my undergraduate and graduate studies I heard about a number of professors who developed cancer. So it looks like I am at a greater risk of developing a cancer than a person who works outside of a research field. Since there is no cure for cancer, the best solution is prevention.
Botanical and nutritional compounds have been used for the treatment of cancer throughout history and may be useful in the cancer prevention. Population studies suggest that high consumption of vegetables and fruits is associated with a reduced risk of cancer. Numerous fruits, vegetables and berries contain cancer chemopreventive compounds. Cabbage, garlic, tomatoes and barriers are some of the examples (see Table 1 for more details).
Several lead compounds, such as genistein from soybeans, lycopene from tomatoes, brassinin from cruciferous vegetables, sulforaphane from asparagus, indole-3-carbinol from broccoli, and resveratrol from grapes and peanuts are in preclinical or clinical trials for cancer chemoprevention 1. This gives us another reason to include as many fruits and vegetables in our diet as possible. I would like to provide more details on the cancer fighting compounds found in foods and I will start with my favourite vegetable (which is according to scientific classification is actually a fruit) – tomato.
Tomatoes contain lycopene which is an antioxidant compound that gives tomatoes and certain other fruits and vegetables their color. The antioxidant activity of lycopene is twice that of beta carotene. The observational case-control studies showed that the risk for some types of cancer is lower in people who have higher levels of lycopene in their blood 2. However, there are other studies that saw no effect.
Since tomatoes also contain vitamins, potassium, and other carotenoids and antioxidants, it may be that other compounds in tomatoes may account for some of the protective effects first thought to be due to lycopene.
To test whether lycopene is responsible for cancer fighting capabilities of tomatoes, one animal study compared lycopene supplements to powdered tomatoes. The rats that received tomato powder had much lower cancer risk, whereas the rats receiving lycopene supplements did not differ significantly from the group that received no special supplements 3.
While the researchers are trying to figure out what is the substance responsible for the cancer fighting power of tomatoes, we can include this vegetable in our daily diet and enjoy its taste and health benefits.
1 Gullett, N. P. et al. Cancer prevention with natural compounds. Semin Oncol37, 258-281, doi:S0093-7754(10)00093-X [pii]
2 Park, E. J. & Pezzuto, J. M. Botanicals in cancer chemoprevention. Cancer Metastasis Rev21, 231-255 (2002).
3 Boileau, T. W. et al. Prostate carcinogenesis in N-methyl-N-nitrosourea (NMU)-testosterone-treated rats fed tomato powder, lycopene, or energy-restricted diets. J Natl Cancer Inst95, 1578-1586 (2003).