Taken together, meat consists of a few, not clearly defined cancer-promoting and a lot of cancer-protecting factors.
Meat and cancer: meat as a component of a healthy diet.
Konrad Biesalski, a nutrition expert at the University Hohenheim in Stuttgart, also noted the counterintuitive reality that many of the nutrients implicated in protecting against cancer, such as vitamin A, folic acid, selenium, and zinc, for which we have been told to eat more fruits and vegetables, are not only more abundant in meat but are also more “bioavailable,” meaning that they are more easily absorbed by humans into the bloodstream when eaten in meat rather than in vegetables (Biesalski 2002).
Based on epidemiological studies it is assumed that meat, especially red meat, enhances risk for cancer, particularly of the colon, breast and prostate. Meat and meat products are important sources of protein, some micronutrients and fat. High fat intake has been blamed for correlation with different diseases, including cancer. Meat protein is reported to contribute to cancer formation. However, meat, including liver, is not only composed of fat and protein, it contains essential nutrients which appear exclusively in meat (vitamin A, vitamin B12) and micronutrients for which meat is the major source because of either high concentrations or better bioavailability (folate, selenium, zinc). In particular, vitamin A, folate and selenium are reported to be cancer-preventive, with respect to colon, breast and prostate cancer. Taken together, meat consists of a few, not clearly defined cancer-promoting and a lot of cancer-protecting factors. The latter can be optimized by a diet containing fruit and vegetables, which contain hundreds of more or less proven bioactive constituents, many of them showing antioxidative and anticarcinogenic effects in vitro.