People who eat a lot of bread are at greater risk of kidney cancer, Italian research has suggested.
Eat vegetables rather than bread, the research suggests
The study of more than 2,300 people also claimed pasta and rice could moderately raise the risk, while vegetables and poultry reduced it.
Cancer Research UK said it was the first time such a claim had been made and warned people not to be alarmed.
A spokesman for the charity said smoking and being overweight were the only well-established avoidable causes.
More than 6,600 people are diagnosed with kidney cancer each year in the UK.
Lifestyle and diet
In the study, researchers from the Institute of Pharmacological Research in Milan, matched each of the 767 adults with kidney cancer with two control patients, who did not have the disease.
They then looked at their personal and family medical history, lifestyle and diet over the past two years.
The scientists were trying to discover which foods increased the risk of renal cell carcinoma.
The research, published in the International Journal of Cancer, found patients who ate more bread had a higher risk of kidney cancer.
It said there was a modest rise in the risk with pasta and rice, but a reduction among patients who ate more poultry, processed meat, and vegetables, whether raw or cooked.
Other products, including coffee, tea, eggs, red meat, fish, cheese, potatoes and fruit, appeared to have no bearing.
The report suggested the high glycaemic index of bread, pasta and rice could be a factor in raising the risk.
High GI foods raise blood sugar levels dramatically which is thought could feed the growth of tumours in some way.
But Ed Yong, of Cancer Research UK, said the study involved patients remembering what they had eaten over two years which could have led to inaccuracies.
"So, we will need more evidence from much larger studies before we can say if this link is real," he said.
"At the moment, the only well-established avoidable causes of kidney cancer are being overweight or obese, which accounts for one in four cases, and smoking, which accounts for one in five cases."