Friday, March 22, 2013

The Myth of Sugar-Loving Tumors

I went out to dinner with a friend of mine last night who asked me if sugar feeds tumors. He had seen some sort of presentation where someone showed sugar being taken up by tumors.   I see these kinds of things on Facebook posts all the time and scroll by.  But when friends pose these questions to me over a plate of pasta, I take the concern a little more seriously.  
                So what are the facts here? Well, cancer cells and tumors need calories and nutrients just like the healthy cells in our bodies.  While cancer cells do feed off sugar, healthy cells do too. So yes, if you give a tumor sugar in a petri dish it will surely be taken up by the cancer cells – but so will all the other cells of your body.  It also makes for some nice scary pictures to post on Facebook and for an overly simplistic message about how cancer cells operate.
                Research shows that eating sugar doesn’t speed up cancer growth.  If you want to shut off what feeds cancer, you have to shut off what feeds all of your cells. You would starve and kill the cancer cells but you would also starve and kill healthy cells and die.  Some research shows that there may be some sort of link between high insulin levels and growth of some cancers.  Some people pump out too much insulin when they eat too many carbohydrates.  But many of us have normal insulin levels. 
                We do know that obesity may be a risk factor some cancers. So eating too much sugar and other calorie dense foods could be an indirect factor in some cancers. In fact, one of the first recommendations by the American Institute for Cancer Research for cancer prevention is to be as thin as possible without being underweight.  They also recommend eating fewer calorie dense foods – including sugar sweetened beverages. These foods can increase weight.  It’s the weight gain that can lead to many problems – including too much insulin – and that increases the risk of some cancers.
                But notice I said some cancers.  And this is another area of misconception about cancer. Cancer is not just one disease. While there are common themes to all cancers – such as all cancers start with some sort damage to genes –  risk factors and causes of each of the cancers are not always the same. For instance, the human papilloma virus is a cause of cervical cancer and possibly some oral cancers but not of other types of cancers.  Weight gain seems to be a risk factor for cancers in the esophagus, pancreas, colon/rectum, endometrium, kidney, gallbladder, and postmenopausal breast cancers. It may not be much of a risk factor for cancers in the lung, ovaries, or stomach.
                The bottom line is that we should all be moderate with sugar. But it is the not the tumor-feeding fiend a lot of people make it out to be.  You can also check out this excellent explanation of this myth on the Mayo Clinic website.
Beth Kitchin PhD RD
Assistant Professor, Nutrition Sciences
University of Alabama at Birmingham 


  1. The common denominator in all of these bandwagons people are so willing to jump on is that it provides The Answer and The Answer is always to eliminate a "bad food". There is a real need for a simple explanation for complex diseases that, for all our medical advancement, can still kill us.

  2. You mean to tell me that you think Americans eat a "normal" amount of sugar for what their body is designed to handle?

  3. No Bradley - that's not what I said in this blog at all. I'm not sure where you got that impression.