Some of my patients, determined to get sugar out of their diets completely, have gotten me to take a closer look at the sugar-cancer connection.  I’ve never been a big fan of sugar. Like many people, I have a hard time avoiding it entirely and always felt that advising people to do so would take away much of their enjoyment in eating.  I’ve compromised, but over time, have edged closer to the no-added sugar (or high-fructose corn syrup) side.

Here’s how the sugar-cancer connection is laid out, based on current research:

Cancer cells do rely on sugar (glucose) to produce energy but all cells use sugar. Cancer cells are no different in that regard except that they use even more sugar than regular cells because they are so “energetic.”

It’s high insulin levels that really seem to promote cancer cell growth. High insulin levels are most likely to come from insulin resistance, where cells can’t allow insulin to bring glucose into the cell. As a result, the pancreas makes more insulin, until, finally, it poops out and you need to take insulin injections.

What exactly causes insulin resistance isn’t known. The big risk factors are the same ones that cause type 2 diabetes: obesity, lack of exercise, lack of muscle, and a high-carbohydrate, high-sugar, excess-calorie diet. Even some nutrient deficiencies, like magnesium, chromium, vitamin D and B vitamins are associated with insulin resistance. Not surprisingly, a high-sugar diet depletes your body of these nutrients.

How does insulin promote cancer?  According to Craig Thompson, M.D., a world-renown cancer researcher, and now, president of Memorial Sloan-Kettering Cancer Center in New York, the more insulin they get, the better cancer cells do. Cancer cells rely on what’s called “insulin signaling” to develop, and they can develop mutations to take full advantage of insulin, increasing its influence on the cell.  Dr. Thompson has said he 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.

So the bottom line, as I see it, is how do we reduce insulin resistance and high insulin levels? The same way we control or even reverse type 2 diabetes. Here’s what I tell my patients to do:

Get regular exercise, both aerobic and muscle-building.

  • Attain a normal body weight, or, at least, a weight at which you can be physically active and feel good.
  • Avoid concentrated sources of sugar, such as soda, sweetened fruit juices and teas, candy, and desserts. Even be careful how much real fruit juice you consume (no more than 6 ounces a day.) Eat fruit instead.
  • Get away from refined carbohydrates such as white flour. Focus on whole grains, beans, lentils, brown rice, sweet potatoes, nuts and seeds, and vegetables like carrots for your carbohydrates. If you think you are intolerant of gluten, don’t eat it!
  • Replenish micronutrients as needed.  You may benefit from supplements of magnesium, chromium, vitamin D, B vitamins and other nutrients found in a multi-vitamin if your diet or absorption ability has been lacking.

By Gale Maleskey, MS, RD


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