Wednesday, July 27, 2011

Obesity causes cancer

According to the American Institute for Cancer Research, more than 100,000 cancer cases in the U.S. are linked to excess body fat - most of them are preventable. Obesity accounts from between around 50 to10 % of various types of cancer.

49% of endometrial cancers (20700 cases per year)
35% of esophageal cancers (5800 cases per year)
28% of pancreatic cancers ( 11900 cases per year)
24% of kidney cancers ( 13900 cases per year)
21% of gallbladder cancers (2000 cases per year)
17% of breast cancers (33000 cases per year)
9% of colorectal cancers (13200 cases per year)

Fat cells used to be thought of as inert stores of calories. We now know that fat is a complex and multifaceted organ system. Recent theory suggests that we put on increased weight over winter as a part of our immune system response to assist in the protection against bacteria and viruses. Short term inflammation is essential for our response to toxic invaders. However, in obese people fat becomes a major producer of inflammatory and chronic inflammation is closely linked with most (if not all ) forms of chronic illness including cancer. Additionally, in obese people, the adipose cells have the incredible capacity to increase their diameter 10- to 15- fold. The enlarged adipose size results in greater production of regulatory factors and unbalances the normal metabolic pathways, resulting in systemic chronic inflammation.

Recent research has found that infiltration of macrophages (white blood cells which are part of the immune system) in subcutaneous adipose tissue is greatly increased in obese people by up to 50% of cell content compared to 10% in lean subjects. The small number of macrophages in lean subjects are also category M2 whereas the recruited macrophages in obese persons are of category M1. M1 are responsible for the production of pro inflammatory cytokines (messengers) such as Interleukin 6 (IL6), Tumor Necrosis Factor alpha (TFNα) and monocyte-chemoattractant protein-1 (MCP-1). All of which have been linked with increased risk of cancer and have shown to be responsible for the activation of factors know to be active in several tumour types in humans.

Recent research has also demonstrated a close a link between inflammation and tumour growth. Including studies showing increased weight gain significantly associated with increased death rates for all cancers. Other studies have also demonstrated that dietary and genetic obesity strongly enhances the development of cancers in laboratory animals.

The research is now overwhelming. Obesity is a major and avoidable cause of many cancers.

Also check out my blog on What is cancer

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