Vitamin consumption 'moderately reduces' pancreatic cancer risk: Chinese meta-analysis
Pancreatic cancer is among the most malignant of cancers, with a five-year survival rate of a mere 5%. In China, where the incidence of pancreatic cancer has been rising in recent years, nearly 80% of sufferers are already in the late stages of the illness by the time they are first diagnosed.
The effects of vitamin intake on pancreatic cancer risk has attracted attention but continues to be disputed. As such, a meta-analysis led by China's Qiqihar Medical University was conducted to investigate the link between vitamin intake and pancreatic cancer risk.
The researchers assessed 25 correlative studies on the subject, with a total of 1.21 million participants. They examined relative risks using either a random- or fixed-effect model, and used sub-group, dose-response, sensitivity and meta-regression analyses to analyse the studies.
The vigour of vitamins
Subsequently, they reported that a 25% decrease in pancreatic cancer risk among the study participants who had taken vitamin D, and a 27% decrease among those who had taken vitamin B12.
They wrote that vitamin D could up-regulate p21 and p27 proteins during the growth inhibition of pancreatic cancer cell lines, and vitamins A, C and E could help to lower the incidence of pancreatic cancer in hamsters.
Furthermore, vitamin E was shown to induce apoptosis in human pancreatic cancer cells and activate EGR-1, a known tumour suppressor gene. It was also found to restrict pancreatic cancer cell growth in humans by obstructing certain inflammatory pathways.
Vitamin K was reported to inhibit pancreatic cancer cell survival through a caspase-dependent pathway, and thiamine to reduce proliferation in pancreatic cancer cell lines.
A cautious conclusion
Despite the results of the reviewed studies having generally shown the favourable effects of various vitamins on pancreatic cancer risk, the researchers concluded that although "vitamin intake can moderately reduce the risk of pancreatic cancer — particularly the consumption of vitamin D and vitamin B12 — the mechanisms of vitamins reducing the risk of pancreatic cancer needs further investigation".
Source: Medicine
http://dx.doi.org/10.1097/MD.0000000000010114
"Vitamin intake and pancreatic cancer risk reduction: A meta-analysis of observational studies"
Authors: Ying Liu, et al.
