Too much iron in diet can trigger bowel cancer, warn experts

Too much iron in your diet can increases the risk of developing bowel cancer, Scottish doctors have discovered.

They have found that high levels of iron in food can 
adversely affect a person’s anti-cancer gene, called APC.

Experts at Glasgow’s Beatson Institute for Cancer Research say patients with faulty APC genes are up to three times more likely to develop the cancer.

The study could also explain why iron-rich foods, such as red meat and fortified cereals, can increase a person’s risk.

Iron is needed to help red blood cells deliver oxygen to the rest of the body and too little can cause illnesses such as anaemia.

This is the first study to illustrate too much of the mineral can increase the risk of bowel cancer – the third most common cancer in Scotland.

The team found the cancer was more likely to develop in mice with a faulty APC gene that were fed high amounts of iron compared with mice who still had a working APC gene. In contrast, mice with a faulty APC gene fed a diet low in iron did not develop bowel cancer at all.

Study author Professor Owen Sansom, deputy director at the Beatson Institute, said: “We’ve made a huge step in understanding how bowel cancer develops.

“The APC gene is faulty in around eight out of 10 bowel cancers but until now we haven’t known how this causes the 
disease.

“It’s clear iron plays a critical role in controlling the development of bowel cancer in people with a faulty APC gene. Intriguingly, our study shows that even very high levels of iron in the diet don’t cause cancer by itself, but rely on the APC gene.” He said the results showed iron could be raising the risk of bowel cancer, by increasing the number of cells in the bowel with APC faults.

The more of these cells in the bowel, the greater the chance that one of these will become a starting point for cancer, according to a study published today in medical journal, Cell Reports.

Prof Sansom said the Glasgow centre, along with scientists from the University of Birmingham, would now begin developing treatments to reduce the amount of iron in the bowel.

He hopes drugs will be available within the next few years.

Dr Julie Sharp, of Cancer Research UK said: “These findings suggest a potentially effective way of reducing the chances of bowel cancer developing in people who are at high risk.

“Finding ways of ‘mopping up’ the iron in the bowel could have a real impact on the number of people who develop the disease.”