November 23, 2015
346 Obesity & Cancer [23 Nov 2015]
Obesity is a growing problem worldwide. Recent data show that 69% of US adults are overweight and half of these are obese. Being overweight causes, or is linked to, increases in many different adverse health markers – blood pressure, blood glucose and insulin levels, insulin resistance, dyslipidemia, and inflammation. Obesity increases the risk or worsens the outcomes of several chronic diseases including diabetes, heart disease and cancer.
The impact of obesity on cancer is significant – it has just overtaken smoking as the top preventable cause of cancer death in the US. About 20% of cancer deaths in that country can be attributed to obesity. The ten types of cancers linked to obesity are: esophagus, postmenopausal breast, liver, kidney, gallbladder, pancreas, colon, prostate, ovary and uterus. Obesity not only increases the risk of developing these cancers but also increases the rate of progression, increases the rate of metastasis, lowers the response to treatment, and reduces survival rates.
The relationship between obesity and cancer is complex with many possible causes for the link. Since I last wrote on this topic (#199 January 2013) based on a 2005 article in Cancer Prevention, researchers have learned more about these factors.
High insulin levels promote cancer growth by interacting with tumor cells’ insulin and IGF-1 receptors. Adipocytes near a tumor are more active in obese people, secreting various cancer-promoting hormones and chemical signals called cytokines.
Inflammation is another process that plays a role in the obesity-cancer link. Obesity increases levels of the COX-2 enzyme which promotes production of prostaglandin E2 (PGE2) which increases inflammation (described in my article #85 October 2010). PGE2 is known to promote progression of breast cancer and the conversion of androgens to (cancer-promoting) estrogens.
Animal studies have found that reducing fat weight isn’t as important as reducing the obesity markers associated with higher cancer risks, particularly insulin, cytokines and IGF-1. So while losing excess fat is still a desirable goal, how you lose it may be more important. A ketogenic diet that normalizes insulin levels (which is at the root of most if not all of the other markers) would be ideal.
Source: "Breaking the Obesity-Cancer Link" by S.D. Hursting et al, The Scientist, 2015
For more information on this or other natural health topics, stop in and talk to Stan; for medical advice consult your licensed health practitioner.