Proof That Sugar Feeds Cancer?

Swedish scientists confirm role played by high blood sugar levels

One in six Britons with high blood-sugar levels faces a greater danger of developing cancer, according to new research.

The findings are worrying because an estimated 10.1 million people in the UK have high blood-sugar, largely as a result of unhealthy lifestyles, especially eating foods containing a lot of sugar, salt or fat.

Excess blood sugar means someone could be more likely both to develop cancer and also to die from it, according to research in the Public Library of Science Medicine journal. Women were more vulnerable than men and high blood sugar is linked to a range of different cancers for each gender, it found .

The 10.1 million people include 2.6 million diagnosed diabetics, 500,000 others who have the disease but do not know it, and a further seven million who have pre-diabetes, a precursor to the full-blown condition.

Scientists at Umea University in Sweden, funded by the World Cancer Research Fund (WCRF), examined blood sugar levels in 274,126 men and 275,818 women from Norway, Austria and Sweden with an average age of 44.8, then followed them up a decade later to see how many had developed or died from cancer.

They write: “Significant increases in risk among men were found for incident and fatal cancer of the liver, gallbladder, and respiratory tract, for incident thyroid cancer and multiple myeloma, and for fatal rectal cancer. In women, significant associations were found for incident and fatal cancer of the pancreas, for incident urinary bladder cancer, and for fatal cancer of the uterine corpus, cervix uteri and stomach.”

Dr Tanja Stock, the lead researcher, said: “The results suggest that, for women, the higher the level of sugar in the blood, the higher the risk. For men, there was still an association, but it was weaker.”

The study is significant because it found that the increased likelihood of cancer occurred regardless of the participants’ body mass index levels. It does not prove that blood glucose of itself leads to cancer, but it suggests that it might promote tumour growth by acting as a source of fuel for tumour cells, especially fast-growing, highly proliferative cells.

Dr Panagiota Mitrou, the WCRF’s science programme manager, said the findings “raise the possibility that controlling blood sugar levels may be a way to reduce risk of some cancers”. A previous South Korean study found the same link, but this is the first research to do so among Europeans.

Dr Iain Frame, director of research at Diabetes UK, said: “This study looked at the link between high blood glucose levels such as those found in people with pre-diabetes and the relative risk of both getting cancer and dying from it. It is important, however, not to oversimplify the findings of this study. It would be wrong to conclude that high blood glucose levels alone are causing the increase in cancer cases and deaths. Nor can we say that, by controlling blood glucose levels alone, we could lower the risk of cancer. There are likely to be other factors at work, such as genetics, diet and levels of physical activity, which are all also linked to both cancer and blood glucose levels,” said Frame.

People could reduce their risk of developing either pre-diabetes or Type 2 diabetes by being more physically active and eating plenty of fruit and vegetables and avoiding foods high in sugar, salt and fat, Frame added.

Dr Laura Bell, Cancer Research UK’s science information officer, said: “This is an interesting study looking at blood-sugar levels and cancer risk, but it’s really only looking at one part of a complicated picture.