Cancer refers to the condition characterized by the rapid growth and multiplication of malignant cells in the body that could be confined to one or more organs or organ systems. There have been several studies that attempt to determine the etiological factors that lead to cancer. One of the most shocking causes has been the consumption of milk and other milk products. Since emphasis is given to the fact that a balanced diet can be the best tool to prevent cancers, the inclusion of dairy products becomes a dilemma. Studies, however, remain unclear and milk, as a carcinogenic agent, is debated.A 1997 research review assembled collectively by the World Cancer Research Fund and the American Institute for Cancer Research found that milk is a strong causative factor for cancer.
The link between milk consumption and cancer:
- Prostate, bladder, and breast cancers: Milk contains insulin-like growth factor (IGF-1) that circulates normally in the blood stream as a protein fragment. It is known to cause prostate cancer in men when elevated beyond the normal ranges as per Cohen’s 1998 study. Another study by Colditz and co-researchers in the same year projected the association of increased IGF-1 levels with breast cancer occurrence in women. Another 2001 study by Anette and co-authors concluded that milk and calcium are beneficial in preventing even premenopausal breast cancer. Since IGF-1 is a protein fragment, or a peptide, increased protein intake through the diet can be a contributing factor in causing these cancers.
- Colorectal cancers: Eunyoung Cho and co-researchers concluded through their study that calcium sources of food, especially milk, are helpful in preventing incidences of colorectal cancer. The World Cancer Research Fund and the American Institute for Cancer Research also reported similar findings and additionally concluded that calcium and milk may play a role in reducing the likelihood of developing bladder cancers.
- Hormone dependent cancers: Ganmaa, a Scientist from Harvard Institute of Public Health, also explained through her study the link that exists between hormones in dairy products, especially estrogen, and cancer. Milk was also said to cause testicular cancer, and the highest prevalence was in Switzerland and Denmark, areas where dairy products are a staple. Algeria, on the other hand, projected the lowest incidence and has been one of the nations that do not consume much dairy products. She also mentions that butter, cheese, and milk were found to be associated with higher rates of cancers that are hormone dependent.
- Recombinant Bovine Growth Hormone: This is a synthetic hormone that is marketed to dairy farmers in order to facilitate enhanced milk production. It is also called bovine somatotropin and is similar to the natural hormone produced in cows with slight differences in the constituent amino acids. This increases IGF-1 circulation in the blood and leads to mastitis and cancers. The FDA has approved the use of bovine somatotropin in the United States; however, it is not permitted in Canada and the European Union.
Though research evidence is strong, currently a balanced diet needs to include dairy products, as they are rich nutritional storehouses providing proteins, carbohydrates, fats, calcium, phosphorous, and some B vitamins. Meeting calcium requirements is definitely a concern and dairy products help attain the right balance.