Red meat is a source of animal fats
Eating a diet high in red meat and dairy products is linked to an increased risk of pancreatic cancer, a US study has suggested.
Researchers followed 500,000 people who had completed a food diary for an average of six years.
The Journal of the National Cancer Institute paper found those who had the most animal fats in their diet had a higher risk of developing the cancer.
UK experts said cutting down on the fats was a way of reducing risk.
There has previously been confusion over whether there was a link between animal fats and pancreatic cancer, with different studies reaching opposite conclusions.
About 7,000 people are diagnosed with pancreatic cancer in the UK each year, with smoking being the biggest risk factor.
The prognosis is poor - the time between diagnosis and death is usually about six months.
This latest research was carried out by the National Cancer Institute in Bethesda, Maryland, which felt earlier studies had been too small to give reliable results.
The participants were being followed to see if they developed a range of diseases.
Of the half a million studied, 1,337 developed pancreatic cancer.
Men who consumed the highest amount of total fats had a 53% higher relative rate of pancreatic cancer compared with men who ate the least.
In women, there was a 23% higher rate of the disease in those eating the most fat compared with those who ate the least.
Overall, people who consumed high amounts of saturated fats had 36% higher relative rates of pancreatic cancer compared with those who consumed low amounts.
Writing in the Journal of the National Cancer Institute, the researchers led by Dr Rachel Stolzenberg-Solomon, said: "We observed positive associations between pancreatic cancer and intakes of total, saturated, and monounsaturated fat overall, particularly from red meat and dairy food sources.
"We did not observe any consistent association with polyunsaturated or fat from plant food sources.
"Altogether, these results suggest a role for animal fat in pancreatic carcinogenesis."
In an editorial in the journal, Dr Brian Wolpin, of the Dana Farber Cancer Institute in Boston, and Dr Meir Stampfer, of the Harvard School of Public Health, said the study was a "welcome addition to the understanding of a disease that is in great need of new insights".
Josephine Querido, senior science information officer for Cancer Research UK, said: "This large study adds to the evidence that pancreatic cancer is more common in people who eat too much fat, particularly saturated fat.
"Understanding ways of reducing the risk of pancreatic cancer is very important because it can be very difficult to treat.
"Apart from stopping smoking, the best way to reduce your risk of cancer is to eat plenty of fruit vegetables and fibre, and to cut down on fatty foods, red and processed meat and limit your intake of alcohol."