Eating three portions of fish a week significantly lowers the chances of bowel cancer, a major new study suggests.

Data from nearly half a million people showed a 12 per cent lower risk among regular fish eaters of the UK’s fourth most common form of cancer.

Oily fish, such as mackerel, salmon and herring, are already thought to reduce the risk of heart disease and protect against brain degeneration, due to the anti-inflammatory properties of their omega-3 fatty acids.

However, the new research is the first of its kind to examine the links between wider fish consumption and bowel cancer in such a large population.

Scientists at the International Agency for Research on Cancer followed 476,160 people from across Europe for 15 years.

Both lean and oily fish were associated with a reduction in colorectal cancers, however no link was observed in the case of shellfish.

Dr Anna Diaz Font, Head of Research Funding at the World Cancer Research Fund, which funded the research, said: “This large study adds to the scientific evidence suggesting that consuming fish could reduce the risk of bowel cancer.

“The biological reasons by which fish consumption potentially lowers risk are not fully understood but one of the theories include specific fatty acids such as omega-3, found almost exclusively in fish, being responsible for this protective effect via their anti-inflammatory properties.”