Clarifying media coverage of a recent study on sugars and cancer

A new study examining how glucose is processed for energy in yeast and cancer cells was recently published in Nature Communications. Not surprisingly, the study received heightened media attention since the press release for the study stated, “Scientists reveal the relationship between sugar and cancer”.

While the study does provide novel findings in understanding basic metabolic pathways in cancer cells, it does not show any evidence that dietary glucose or other sugars are linked to cancer. This was a basic experimental study conducted in the lab that tested a theory about how glucose may be used to regulate the growth of cancer cells. Below are brief highlights of the study:

• The study was conducted in yeast cells, which were cultured in the laboratory to learn more about basic cellular biology and how cells respond under different conditions. Cell culture studies provides the lowest level of evidence among all research types and do not provide conclusions about human metabolism.

• A specific yeast cell model was used to mimic the pathway of glucose usage in cancer cells. It has an inherent defect by providing an unlimited influx of glucose into the cell, which is different from the tight regulation of glucose influx present in normal cells. As a result, the model already had pre-existing features of cancer cells and cannot be used to study any “causal” effect on cancer (i.e. transforming normal cells to cancer cells).

• The study found that glucose (in theory representing blood glucose) activated certain proteins in yeast cells that enable cancer cells to grow and multiply faster. However, in humans, blood glucose concentration is determined by the sum of all factors such as dietary intake of sugars and starch, blood insulin levels, glucose synthesis in the body from other sources, glucose usage and storage in different organs.

• The scientists conducting this study have cautioned that “Some people are interpreting that we have found a mechanism for how sugar causes cancer, but that is certainly not the case.”

There is no one single cause of cancer. Diet is one factor among many that may play a role in cancer initiation or development.

For a more in-depth review of the study, please see:

• International Food Information Council “Fast Take: Does a new study show that sugar causes cancer?”
• WIRED “Cutting Carbs Won’t Save You From Cancer”.