What are the dangers of colorectal cancer?
Colorectal cancer (otherwise known as bowel cancer, rectal cancer or colon cancer) is the 4th most prevalent cancer in the UK liable for 12% of all new cases. In 2015 there were 41,804 new cases of bowel cancer affecting most prominently those aged 85-89. Colorectal cancer is first cancer that was associated with diet due to evidence from ecological studies, dating back to the 1950’s, which suggest a migrant’s risk of developing colorectal cancer can be changed depending on the duration spent in the host country. This was first acknowledged when observations of the Japanese who had migrated to Hawaii had increased incidences of bowel cancer risks compared to those still living in Japan. This was further investigated by the same researcher who conducted another study later on that showed evidence that the incidence of bowel cancer exhibits low risk in Japan but high incidences in America and Western Europe. It is suggested the difference in incidence could be due to significant inter-country differences between food habits, stimulating the investigation of colorectal cancer and its link to environmental factors. These environmental factors include a high intake of processed and red meat, refined grains and carbohydrates, fat, alcohol intake and sugars.
Amongst them, a high iron intake has also been linked with an increased risk of colorectal carcinoma.
This could be due to iron being an essential component in the rapid multiplication of normal and abnormal cells. This is not a new association, as iron has long been thought of as a carcinogenic due to its pro-oxidative qualities and its ability to encourage the production of free radicals and the peroxidation of lipids. It is haem iron in particular which has undergone speculation due to it having a higher bioavailability than non-haem iron. It has been thought that haem iron also increases cytotoxicity and mucosal proliferation and thus has a greater risk of inducing cancer compared to other forms of dietary iron.