New research shows that visceral fat (the fat inside your belly and around organs) makes a protein called fibroblast growth factor-2 (FGF2) in much larger amounts than fat underneath your skin does. FGF2 can convert normal cells into cancerous ones (Oncogene, August 7, 2017). Visceral fat gives you a big belly by forming around the liver, pancreas, and intestines. It also forms around your heart. Many studies show that having excess fat in your belly increases inflammation far more than fat anywhere else, and inflammation increases risk for several cancers (Circulation, 2008;117(13):1658–1667). This new research offers a possible mechanism.
Researchers fattened rats by feeding them a high-fat diet and then caused skin cancers by exposing them to high doses of ultraviolet B rays (UVB). The rats that had the biggest increases in belly fat had the highest levels of FGF2 and the highest rates of skin cancers. The researchers also showed that FGF2 turns skin and breast cells into cancer cells. The study involved both research in mice and tests on human fat cells in the laboratory. The researchers also obtained samples of visceral fat tissue from cancer-free obese human subjects and studied whether incubating this tissue with the epithelial cells that line organs caused cancer. The authors propose that:
• FGF2 levels and abdominal obesity are far better predictors of cancer than just being overweight, and that
• people with big bellies may be able to help prevent cancers by dieting, exercising and avoiding smoking.
Cancers Associated with Excess Belly Fat
A review of 4,641 articles showed that excess belly fat turns on your immunity to cause inflammation which, in turn increases risk for cancers of the colon, rectum, postmenopausal breast, liver, endometrium, esophagus, kidney, stomach, gall bladder, pancreas, ovary, thyroid and multiple myeloma, as well as for heart attacks and diabetes (Cancer Prev Res, September 1, 2017;10(9):494-506). Even those who are not overweight but have big bellies still have significantly increased risk for cancers, heart attacks and diabetes.
The International Agency for Research on Cancer (IARC) reported that being overweight is associated with almost five million cancer deaths each year and increases risk for 17 different cancers: colon, rectum, esophagus, kidney, breast (women), endometrium, stomach, liver, gall bladder, pancreas, ovary and thyroid, as well as fatal prostate cancer and breast cancer in men, meningioma, multiple myeloma and B-cell lymphoma (N Engl J Med, Aug 25, 2016;375:794-798).
Being overweight or obese is the single biggest preventable cause of cancer after smoking. Researchers followed 43,000 participants for an average of 12 years and more than 1,600 people were diagnosed with an obesity-related cancer. They found that adding about 4.3 inches (11 cm.) to your waist increased risk for obesity-related cancers by 13 per cent (breast, bowel, womb, esophagus, pancreas, kidney, liver, upper stomach, gallbladder, ovary, and thyroid). See Excess Weight Raises Cancer Risk.
How to Tell if You Have Excess Belly Fat
Excess belly fat is a sign of too much visceral fat (fat in the liver and around other organs ) that is associated with increased risk for heart attacks, strokes and diabetes as well as many types of cancers. If you can pinch more than three inches of fat under the skin near your belly button, you probably have too much visceral fat. Excess belly fat is generally defined as a waist circumference of more than 35 inches in women and more than 40 inches in men. Your doctor can order an ultrasound test or an X ray of your belly called a CT scan to see if you store excess fat in your liver.
Risk for many types of cancers can be reduced by:
• restricting calories, which lowers insulin and insulin-like growth factor-I (Frontiers in Physiology, 2012;3(318):1–10) and inflammation (Cancer Research, 2012;72(9):2314–2326).
• regular exercise (Nature Reviews Cancer, 2008;8(3):205–211).
• eating lots of fruits, vegetables and other anti-inflammatory foods (Br J Nutr, May 28, 2016;115(10):1699–1710; BMJ, 2006;333(7578):1109–1111 and Nov 10, 2011;343).
If you are overweight, you are increasing your risk for many types of cancer, particularly if you store most of your fat in your belly. I recommend Intermittent Fasting as the most effective way to lose weight and to control weight permanently once you have reached your goal.