April 17, 2019

expert reaction to red and processed meat consumption and risk of colorectal cancer

Research published in International Journal of Epidemiology argues that people who eat red and processed meat within department of health guidelines are still at increased risk of bowel cancer.

Prof David Spiegelhalter, Winton Professor for the Public Understanding of Risk, University of Cambridge, said:

“The bottom line is that, if these results are correct, then the cancer risks of bacon are around double that reported before. That means 100 people would need to eat a bacon sandwich every other day for their whole lives, for one extra case of bowel cancer.  Using the previous estimates, it would have to be every day.”

Dr Gunter Kuhnle, Associate Professor in Nutrition and Health, University of Reading, said:

“This is a very thorough analysis of the link between meat intake and colorectal cancer, and the largest study ever undertaken in the UK. In contrast to previous studies, such as those include in the WHO/IARC opinion, it focuses exclusively on a UK population and is therefore much more relevant for us. It also has a very large sample size and re-measured diet to get a better estimate of meat intakes.

“The results confirm previous findings that both, red and processed meat consumption, increase the risk of colorectal cancer. The increase in risk of approximately 20% per 50g increase of red and 25g of processed meat intake is in line with what has been reported previously. This is largely in agreement with previous findings, although current authors have used 25g increments instead of 50g increments as previous studies have used. The larger reported magnitude of increased risk at 25g of processed meat is likely due to the better methods used to measure meat intake, as better dietary measurement methods usually provide more reliable estimates of risk

“The 20% risk increase with processed meat is not really extremely different to previous findings. The EPIC study has found ~20% for the group consuming 20-40 g. The authors refer to a meta-analysis by the Word Cancer Research Fund, and their estimate is 20% for 50g per day increments (although there seems to be a misprint in the paper as the figures don’t agree). So overall, the findings here (20% for 25g) follow roughly what has been known before.

“The results of this study also question the recent focus on nitrite as the main culprit for colorectal cancer: the authors found very small differences between red and processed meat in this study, even though only processed meat contains nitrite. A reduction or removal of nitrite from meat products would therefore have only little impact on cancer risk. The study also shows that dietary fibre reduces the risk of colorectal cancer An increased consumption of fibre, as shown by this study, would be of considerably more benefit.”

“The importance of the study is not the novelty of the results, but that it confirms previous findings, based largely on dietary data from the 90s, with much more recent dietary data and exclusively in a UK population. So any criticism that was made at previous studies regarding the transferability of results to the UK is being addressed.”

‘Diet and colorectal cancer in UK Biobank: a prospective study’ by Kathryn Bradbury et al. was published in International Journal of Epidemiology at 00.01 UK time Wednesday 17 April.

Declared interests

Dr Gunter Kuhnle: “I have been working on an EU funded project “PHYTOME” to investigate methods to remove nitrite from meat. But otherwise I don’t have anything to declare here.”

None others received.