Cancer Research UK cautious over fatty fish cancer protection link
Preliminary research has suggested that women who eat fatty fish, such as salmon or mackerel, a few times a month might have a lower risk of a type of kidney cancer.
But Cancer Research UK played down the research, pointing out that it was the only such study to show an effect on kidney cancer, and that the results would need confirming in further studies.
"Several studies have looked at the possible anti-cancer benefits of eating oily fish," said Henry Scowcroft of Cancer Research UK. "Some studies show a link, and some don't."
"This appears to be the first study looking at whether a diet high in oily fish might protect against a particular type of kidney cancer, and the results needs to be repeated before we can draw any firm conclusions."
The study drew data from an observational study of 90,000 Swedish women that was initiated in 1987 and followed up until 2004.
At certain intervals over this period, the women filled in questionnaires about what they ate.
At the end of the study, the researchers looked at cancer rates among the women and compared them with the questionnaires.
They found that women who said they ate fatty fish at least once a week were half as likely to get renal cell carcinoma, a type cancer of the kidney, compared to those who never ate it.
"This is the first time that a link between the consumption of fatty fish and renal cancer has been studied," said researcher Professor Alicja Wolk.
"The reason previous studies have been unable to demonstrate a link between fish consumption and renal cancer is that they made no distinction between fatty and non-fatty fish."
They did speculate that the inconclusive results of previous studies which included non-fatty fish could be due to the amount of omega-3 fatty acids or vitamin D in fatty fish, however. Mr Scowcroft added, "We do know that being overweight or obese and smoking both increase the risk of kidney cancer.
"The best advice we can give is to cut down the calories to maintain a healthy body weight, take regular exercise, and of course, to give up smoking."
The study was conducted by the Karolinska Institute in Sweden and published in the Journal of the American Medical Association.