Could Dairy Products Help Reduce the Risk of Colorectal Cancer?
Colorectal cancer is the third most common cancer worldwide, and the fourth most common cancer in the United States. This cancer can vary from the appendix all the way to the rectum and anywhere in between (the colon). Approximately 95% of colorectal cancers are adenocarcinomas, i.e. cancers of the epithelial tissue that have a glandular origin. The epithelium is a type of tissue that by definition lines “hollow structures” which in this case is the colon/rectum. Glands are defined as “organs that synthesize substances (such as hormones) and release them into the bloodstream.” Because of the glandular nature, these cancers tend to metastasize in the bloodstream, making early detection extremely important.
It has been observed that many colorectal cancers are environmental in nature. Therefore, certain consistent dietary habits inculcated from a young age can have a major effect as you get older. This is evident because the colon and rectum are integral parts of the digestive system. Some cases have a genetic predisposition, but this is a factor in about 25% of all cases. There have been correlations for quite some time that dairy products (milk in particular) can help reduce the risk of colorectal cancer. This article will shed light on these claims with academic journal evidence.
There are three articles of interest we will analyze carefully. The first study was published in 2011 by Aune et al. in the Annals of Oncology journal. It is a meta-study (a research study that summarizes/incorporates other studies to yield a succinct conclusion) that looks at nineteen studies that indicate an inverse correlation between dairy consumption and reduced risk for colorectal cancer. The general conclusion was that milk has the best inverse correlation compared to other dairy products such as cheese. An explanation given in the study is that calcium “binds secondary bile acids and ionizes fatty acids thus reducing proliferative effects in the colonic epithelium.” There are some studies that suggest that high amounts of bile acid could lead to colorectal cancer. Because of the calcium's mechanism, it reduces this factor. In addition, Aune et al. states that calcium creates many pathways within cells causing differentiation (changing from one cell type to another) in normal cells and apoptosis (programmed cell death) in transformed cells meaning that healthy cells are maintained while cells that are prone to become cancerous are reduced.
The second article was published in 2013 by Murphy et al., and looks at differing fat content in dairy products. This paper reinforced the relationship between a higher dairy intake and a lower risk of colorectal cancer. In addition, it experimented with varying fat content (regular milk, skim milk, reduced fat milk, etc.) and analyzed if it affected the risk. The conclusion was that fat content doesn't matter in terms of risk for colorectal cancer. This harks back to the idea that the high levels of calcium in dairy products are what help prevent colorectal cancer. From a public health standpoint, it is beneficial not to incorporate too much fat into one's diet. This will be elaborated more in the conclusion.
If one already has colorectal cancer, could an increased consumption of dairy products help cope with the disease and prevent mortality? The third study of interest, published in 2014 by Yang et al. in the Journal of Clinical Oncology suggests so. In this experiment, a small sample size of just over 2,200 people who had invasive, nonmetastatic colorectal cancer was analyzed. The result was that just above 400 passed away from the illness. Therefore, the study suggests that it may help in these cases as well where the patient has already been diagnosed with colorectal cancer. However, please note that the cancer is invasive, nonmetastatic which means that it hasn't spread (and thus in the smaller stages). There isn't sufficient data on its effect in metastatic cancer, but the fact that Yang et al. went the extra step with this correlation provides promise for future studies.
In conclusion, many research studies have shown that a substantial amount of dairy intake can help reduce the risk for colorectal cancer. However, great care must be taken in implementing this idea. There are other studies which see a correlation between increased dairy consumption and an increased risk for prostate cancer. As a result, it is imperative that you consult your health care professional and/or a certified dietician before starting a strict regimen. Moderation is key. In addition, despite the results from the second study mentioned above, high fat has the potential to be harmful to the rest of the body if not consumed carefully. Based on this information, it is extremely important that we remember that the human body needs to be considered as a whole instead of just parts. By implementing some proper dietary habits (preferably from a younger age), America and the rest of the world may prevent major cancers that afflict us at present. As mentioned in my previous articles, prevention is truly better than cure.
About SC Ali
S.C. Ali is an author/editor. He has a degree in Chemistry, and is interested in the study and practice of medicine. His blog can be found here: http://thebronzelifestyle.com/