Does Fructose Really Cause Cancer?

This week it’s impossible to miss the headlines that fructose causes breast and pancreatic cancer. But does this really mean we have to pour our OJ down the drain and compost our dried dates and raisins, vowing never to approach the fruit aisle at the supermarket again?

What all the reporting is leaving out is the reason why fructose is associated with cancer. The simple reason is that sugar isn’t just burned by cells. Sugar also becomes the backbone of DNA.

DNA is composed in part of incredibly long chains of ribose sugar. It’s easier for those cells to make ribose from fructose than it is for them to make it from any other source. However, the process is not automatic.

The conversion of fructose to pentose only occurs when there are also fluctuations in an enzyme called transketolase. This enzyme responds to excess sugar, not necessarily by fructose sugar. It’s not just the presence of fructose that triggers the production of large amounts of ribose. It’s also consuming too many carbs in general. There is a sudden enthusiasm for the more natural cane sugar, or sucrose, but it’s essential to remember that sucrose is a chemical combination of glucose and fructose. You don’t avoid fructose by eating cane sugar.

But what does all this have to do with cancer, anyway?

In the proliferation stage of cancer development, cancer cells need to make lots of DNA so they can divide to create lots of cancer cells. Fructose does not cause cancer. It does not really “fuel” cancer. It provides the raw materials for cancer cell (and healthy cell) DNA. If
you consume tiny amounts of fructose, you don’t trigger the massive production of ribose in cancer cells.

There is a difference, of course, between high-fructose corn syrup and fructose from fruit. “High” fructose isn’t 100% fructose. It’s also glucose, just in a different ratio than table sugar. The idea for using high-fructose corn syrup is that it doesn’t dry out the same way that cane sugar does, and it’s a nifty excuse for planting lots of corn, selling lots of seed and fertilizer and tractors, creating a new commodity for hedge funds, and so on. Eating no more than about 15 grams (3 spoons) up to twice a day won’t trigger the nasty reactions that accelerate cancer proliferation, and eating a single piece of fruit earlier in the day and another piece of fruit later in the day won’t, either.


Dunking a dozen doughnuts, on the other hand, is practically a prescription for cancer growth. It’s just important to remember that with fructose as with everything else, stay within a healthy limit. And it’s probably best to avoid high-fructose corn syrup altogether, if only to send the hedge fund managers, GMO creators, and pesticide purveyors a lesson.

Robert Rister grew up in a farming family who raised 1,000 acres of cotton, sorghum, vegetables, and corn, in addition to maintaining an herb garden for four generations. Chemist, herbalist, and formulator of natural health products, Robert is the author or co-author over twenty books on natural health, including Healing without Medication and the forthcoming Coconut Grove Diet.

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