Cancer: Driven By Sugar & Carbs

Memorial Sloan Kettering President and CEO Craig B. Thompson discusses how cancer cells grow and spread, and explains the link between cell growth and metabolism. He also discusses the link between excess sugar in the diet and cancer, a focus of his laboratory research. He explains that sugar supplies nutrients that tell the cells to divide “and then you’re off to the races of initiating the formation of a human cancer.”

Uncle Pete’s summary notes from these videos:

  1. The most exciting biological event in our lifetime is the sequencing of the human genome. Knowledge about how cancer works is now growing exponentially. We have learned something very important while investigating the human genome over the last five years: you do not inherent cancer!  Only a very small percentage of people have inherited genes that predispose them to cancer. Environmental factors are the number one determination of cancer risk.
  2. Human genome researchers have sequenced the genomes of Sloan Kettering cancer patients and have found the common mutations among all cancers. These mutations are all in the genes that control glucose uptake.
  3. In 2012 the National Cancer Institute announced that a new #1 cause of preventable cancer has emerged: diet and obesity have replaced tobacco as the leading cause of preventable cancer. 
  4. Overeating carbohydrates is the issue. As you become obese you can no longer properly store glucose in muscle and fats cells, so you distribute the overabundance of glucose to all the other cells in your body (note: even skinny people accumulate visceral fat).  This sets in motion the genetic mutations for glucose uptake and you are off to the races in forming cancer.
  5. The type of food you eat matters. Food consists of fats, proteins and carbohydrates. We have spent the last 40 years as a community trying to convince ourselves that fat is the cause of all problems. Every study has failed to do so. Limiting fats does not reduce the incidence of cancer, however if you vary the carbohydrates of the diet the cancer incidence goes up with every percentage increase of the carbohydrates that you overeat. Fats have no effect on cancer, carbohydrates do and proteins are somewhere in the middle.
  6. Armed with this information we have to change the nutritional advice. We are starting to think about how we limit the cancer’s fuel supply (glucose). Hopefully we will take that into the clinic.
  7. NYC mayor Bloomberg has it right by trying to limit the consumption of sugary drinks.

Here are some quotations from Craig B. Thompson and Lewis Cantley, Director of the Cancer Center at Beth Israel in Boston in a New York Times Magazine article published in 2011:

Is Sugar Toxic?

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…. 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.

If it’s sugar that causes insulin resistance, they say, then the conclusion is hard to avoid that sugar causes cancer — some cancers, at least — radical as this may seem and despite the fact that this suggestion has rarely if ever been voiced before publicly. For just this reason, neither of these men will eat sugar or high-fructose corn syrup, if they can avoid it. “I have eliminated refined sugar from my diet and eat as little as I possibly can,” Thompson told me, “because I believe ultimately it’s something I can do to decrease my risk of cancer.” Cantley put it this way: “Sugar scares me.”


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