Data from residents in the San Francisco Bay Area found that consuming at least 850 milligrams of omega-3 fatty acids per day was associated with a 53 percent reduction in the risk of pancreatic cancer, compared to intakes of between 330 and 580 milligrams per day.
According to findings published in the International Journal of Cancer, benefits were also observed for intakes of vitamin C and E, the highest average intakes associated with 31 and 33 percent reductions, respectively, compared with the lowest average intakes.
On the flip side, researchers from the University of California San Francisco report that high intakes of saturated fats and certain monounsaturated fatty acids may increase the risk of pancreatic cancer – the fourth most common cause of cancer mortality in the US and the cause of 33,400 deaths among men and women in 2007.
“Results from this large population-based case-control study provide additional evidence that dietary factors and use of supplements may affect risk of pancreatic cancer,” wrote the researchers, led by Paige Bracci from the Department of Epidemiology and Biostatistics.
“Our results showing increased risk of pancreatic cancer with increased saturated fatty acid intake and decreased risk with high intake of long-chain omega-3 fatty acid and of vitamin C and E from supplements contribute new data to the epidemiologic literature on pancreatic cancer,” they added.
Bracci and her co-workers analysed data from 532 people with pancreatic cancer and compared this with data from 1,701 cancer-free individuals.
High intakes of saturated fats were associated with a 60 percent increase in the risk of pancreatic cancer, while intakes of palmitoleic and oleic monounsaturated fatty acids were associated with 60 and 40 percent increases, respectively.
Furthermore, linolenic acid – a polyunsaturated fatty acid – was also associated with an increase in cancer risk, added the researchers.
In terms of benefits, however, the San Francisco-based researchers calculated that increased intakes of omega-3s. Furthermore, high intakes of vitamins C and E from supplements were also associated with a decrease in cancer risk.
Commenting on the potential mechanisms, the researchers noted that the antioxidant properties of the vitamins may explain the benefits since they “are known to have anticarcinogenic effects. Vitamins C and E can block reactive oxygen species, reducing oxidative stress and thus reducing cancer-causing mutations.
“Vitamins C and E may also alter pancreatic cancer risk through their ability to stimulate immune function,” they added.
Regarding the role of fats, Bracci and her co-workers stated that the “biologic mechanisms to explain how dietary fat may affect risk for pancreatic cancer remain to be elucidated”. They did note, however certain fatty acids have been linked to increased production of bile acids which could increase the reflux of bile in the pancreas and promote cancer formation.
Source: International Journal of Cancer
Volume 127, Issue 8, Pages 1893-1904
“Intake of fatty acids and antioxidants and pancreatic cancer in a large population-based case-control study in the San Francisco Bay Area”
Authors: Z. Gong, E.A. Holly, F. Wang, J.M. Chan, P.M. Bracci