Obesity in Developing World Leads to ‘Fat Cancers’

Increasingly the developing world is suffering from the ‘fat cancers’ that have come to be associated with wealthy countries, says this article in the Huffington Post.

It appears that the elevated levels of insulin and other hormones associated with a processed diet and obesity promote the growth of cancer cells.

From the NY Times Magazine a few weeks ago, from a controversial article “Is Sugar Toxic?”:

In 1984, Canadian physicians published an analysis of 30 years of cancer incidence among Inuit in the western and central Arctic. While there had been a “striking increase in the incidence of cancers of modern societies” including lung and cervical cancer, they reported, there were still “conspicuous deficits” in breast-cancer rates. They could not find a single case in an Inuit patient before 1966; they could find only two cases between 1967 and 1980. Since then, as their diet became more like ours, breast cancer incidence has steadily increased among the Inuit, although it’s still significantly lower than it is in other North American ethnic groups. Diabetes rates in the Inuit have also gone from vanishingly low in the mid-20th century to high today.

Now most researchers will agree that the link between Western diet or lifestyle and cancer manifests itself through this association with obesity, diabetes and metabolic syndrome — i.e., insulin resistance. This was the conclusion, for instance, of a 2007 report published by the World Cancer Research Fund and the American Institute for Cancer Research — “Food, Nutrition, Physical Activity and the Prevention of Cancer.”

So how does it work? Cancer researchers now consider that the problem with insulin resistance is that it leads us to secrete more insulin, and insulin (as well as a related hormone known as insulin-like growth factor) actually promotes tumor growth.

As it was explained to me by Craig Thompson, who has done much of this research and is now president of Memorial Sloan-Kettering Cancer Center in New York, the cells of many human cancers come to depend on insulin to provide the fuel (blood sugar) and materials they need to grow and multiply. Insulin and insulin-like growth factor (and related growth factors) also provide the signal, in effect, to do it. The more insulin, the better they do. Some cancers develop mutations that serve the purpose of increasing the influence of insulin on the cell; others take advantage of the elevated insulin levels that are common to metabolic syndrome, obesity and type 2 diabetes. Some do both. Thompson believes that many pre-cancerous cells would never acquire the mutations that turn them into malignant tumors if they weren’t being driven by insulin to take up more and more blood sugar and metabolize it.

What these researchers call elevated insulin (or insulin-like growth factor) signaling appears to be a necessary step in many human cancers, particularly cancers like breast and colon cancer. Lewis Cantley, director of the Cancer Center at Beth Israel Deaconess Medical Center at Harvard Medical School, says that up to 80 percent of all human cancers are driven by either mutations or environmental factors that work to enhance or mimic the effect of insulin on the incipient tumor cells. Cantley is now the leader of one of five scientific “dream teams,” financed by a national coalition called Stand Up to Cancer, to study, in the case of Cantley’s team, precisely this link between a specific insulin-signaling gene (known technically as PI3K) and tumor development in breast and other cancers common to women.At a minimum, we should make sure we get age-appropriate screening, such as mammograms and colonoscopies.  I got my first colonoscopy after I turned 50 – no fun (the procedure was fine – it was the “prep” that was a challenge) – but I was glad to know that it was notmal.

Over the course of the last thirty years obesity rates worldwide have doubled. Obesity has hit the West especially hard, but developing countries are suffering too. Obese people are thought to be at a higher risk for ‘fat cancers,’ such as breast and colon cancer. Instances of these cancers, common in obese wealthy countries, are now becoming more prevalent in the developing world.

“Sadly, changing ways of life, such as reduced physical activity, are making people unhealthier and in turn prone to such diseases as cancer,” Dr. Eduardo Cazap, president of the Union for International Cancer Control, said in a statement released by the World Health Organization.

In order to combat instances of cancer, the World Health Organization recommends 2.5 hours of moderate physical activity a week. Don’t think that this is just a Third World problem. The American Institute for Cancer Research/World Cancer Research Fund estimate that 340,000 cases of cancer could be prevented here in the United States by people eating better, exercising, and keeping their weight down.

At a minimum, we should get age-appropriate screening, such as mammography and colonoscopy.  These generally start at age 50 for those without a family history.  I got my first colonoscopy when I turned 50.  It wasn’t fun – the procedure wasd fine; it was the prep that was rough – but I was glad to get a clean bill of health there. 

 

Dr John Ellis MD

Board-certified anesthesiologist, with expertise in cardiovascular anesthesia and the implications of obesity and sleep apnea in anesthesia. See vascularanesthesia.com for professional information. Dr. Ellis has used the strategies in here to: (1) lose 120 lbs over 18 months, (2) stop all antihypertensive medicines, and (3) no longer need CPAP treatment for sleep apnea.

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