Red meat, fish, fibre, and colorectal cancer

Message

Eating large amounts of red meat, without much in the way of fibre or fish, increases the risk of colorectal cancer. Eating fish appears to reduce the risk.

Reference

T Norat et al. Meat, fish, and colorectal cancer risk: the European prospective investigation into cancer and nutrition. Journal of the National Cancer Institute 2005 97: 906-916.


Background

High consumption of red or processed meat has been associated with increased risk of colorectal cancer in previous analyses. The problem is one of confounding, where people who eat lots of red or processed meat eat less of other things, particularly fibre. It needs a very large study to adequately investigate the various interactions.

The EPIC study is a prospective cohort designed to investigate relationships between diet, lifestyle, and environmental factors and cancer. It includes about 360,000 men and 153,000 women mostly aged 35 to 70 years recruited in 10 European countries.

Results

The 478,000 participants contributed 2.2 million person years of follow up, with an average of 4.8 years. There were 1329 diagnosed cases of colorectal cancer (0.6% per year), 95% of which were histologically verified.

There were trends for higher risk of colorectal cancer with increased red meat and processed meat. Consumers in the highest band of processed meat consumption (more than 80 grams a day) has a significantly raised risk (Hazard ratio 1.4, 95% CI 1.1 to 1.9).

There was a strong trend for reduced risk of colorectal cancer with increased fish consumption, with significantly reduced risk for those consuming an average of 40 grams a day or more (Hazard ratio 0.76, 95% CI 0.5 to 0.8). There was no relationship for different levels of poultry consumption.

Significant interactions occurred between consumption of red or processed mean, and consumption of fish, and of fibre. There was no significant increased risk of colorectal cancer with high intake of red or processed meat in the presence of high intake or fish (Figure 1) or fibre (Figure 2).

Figure 1: Relationship between red or processed meat consumption and fish consumption

Figure 2: Relationship between red or processed meat consumption and fibre consumption

Comment

This extraordinarily large and detailed study emphasises that sensible eating can result in sensible risks. Eating some red meat, some fish, in a diet with sensible amounts of fibre makes very good sense.