According to the National Cancer Institute, obesity is a condition in which a person has an abnormally high and unhealthy proportion of body fat. Obesity is measured by calculating a person’s BMI. Years of research prove that there are connections between obesity and cancer risk.
Research shows us that an increase in body weight increases insulin levels in the blood, which promote the development of certain tumors and tumor regulators. Fat cells also produce adipokine hormones, which stimulate cell growth. Leptin, which is abundant in obese people, acts on a receptor on the brain where a person exhibits appetite and promotes cell proliferation, or cell growth. Essentially, excess body weight is the catalyst for hormones in the body to not function properly while additionally promoting cell growth, which is the major cause of cancer spread.
In 2007 research found 34,000 new cases of cancer in men and 50,500 new cases in women due to obesity. It is estimated that 1:5 cancer related deaths are due to overweight and obesity. Obesity is associated with several cancers in the body, including in the esophagus, pancreas, colon and rectum, kidney, thyroid, gallbladder, breast (after menopause) and endometrium (the lining of the uterus). Weight gain affects the body’s immune system, certain hormones including insulin and estrogen, and factors that regulate cell division.
Scientists in the American Cancer Society admit that research is limited in learning whether or not weight loss can reduce cancer risk. There is growing evidence to suggest that a reduction in weight may diminish the risk of breast cancer, after menopause, as well as more aggressive forms of prostate cancer. However, obese people who lose weight often reduce certain hormone levels that relate to cancer risk, such as insulin and estrogen.
Cites:
National Cancer Institute
http://www.cancer.gov
The American Cancer Society
http://www.cancer.org
The PubMed Data base
http://www.ncbi.nlm.nih.gov/pubmed