People who eat lots of bread are twice as likely to suffer from kidney cancer compared to people who eat little bread, say researchers from the Mario Negri Institute for Pharmacological Research, Milan, Italy, after looking at the dietary habits of kidney cancer patients.

You can read about this study in the International Journal of Cancer.

The researchers said further studies are needed to confirm the link between bread intake and renal cell carcinoma (kidney cancer).

The researchers looked at details on 2301 adult participants, aged 24 – 79. 767 (494 men and 273 women) of them had kidney cancer while 1,534 (988 men and 546 women) of them did not. Information was gathered on their eating and drinking habits, lifestyle, BMI and medical histories (personal and family).

They found that those who consumed the most bread had a 94% higher risk of developing kidney cancer compared to those who consumed the least bread. Bread consumption ranged from 9 to 28 portions each week.

What exactly does 28 portions of bread mean?

A portion is about one to one-and-a-half slices of bread (50gms or 1.7 ounces). So, 28 portions means between 14 to 20 sandwiches a week, depending on how thick the slices are.

The researchers also found:

— High intake of pasta and rice raises kidney cancer risk 27%
— High intake of milk and/or yoghurt raises kidney cancer risk by 29%
— High intake of poultry lowers risk by 26%
— High intake of processed meat lowers risk by 36%
— High intake of vegetables lowers risk by 35%
— The high intake of the following foods made no difference to risk: coffee, tea, soups, red meat, eggs, cheese, fish, pulses, potatoes, desserts, sugars and fruits

The researchers suggest that the blood sugar raising effects of bread could be playing a factor in increasing the kidney cancer risk. Insulin-like growth factor levels, which play a role in cancer risk, may be affected if a person eats lots of bread. Switching from a high-bread diet to a high vegetable diet could lower a person’s risk, say the researchers.

Comment by Editor of Medical News Today

As the researchers, say, further research is needed. If the high-bread consumers had eaten just high-fiber wholemeal bread, I wonder whether the findings would have been the same. If the researchers suggest the bread is raising the blood-sugar levels, and this may be a factor in raising the risk, why didn’t other starchy foods raise the risk? Was the percentage of smokers (or people who smoked up to diagnosis) the same for the kidney cancer group as for the non-kidney cancer group?

“Food groups and renal cell carcinoma: A case-control study from Italy”
Francesca Bravi, Cristina Bosetti, Lorenza Scotti, Renato Talamini, Maurizio Montella, Valerio Ramazzotti, Eva Negri, Silvia Franceschi, Carlo La Vecchia
International Journal of Cancer – DOI: 10.1002/ijc.22225
Published online: 20 Oct 2006
Click here to see abstract online

Written by: Christian Nordqvist
Editor: Medical News Today