Eating three portions of fish a week reduces risk of bowel cancer, research suggests

Study examined the dietary habits of almost half a million people

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Eating three or more portions of fish per week cuts the risk of bowel cancer, new research suggests.

Researchers from the University of Oxford and the International Agency for Research on Cancer (IARC), examined the dietary habits of 476,160 people who had filled in questionnaires about how often they eat certain foods.

The surveys included detail on the participants’ fish intake, including white, fatty, oily and lean fish.

The results showed that eating 359.1g of any fish per week led to a 12 per cent decreased risk of bowel cancer compared with eating less than 63.49g a week.

Meanwhile, people eating just 123.9g a week of oily fish, such as salmon and sardines, experienced a 10 per cent lower risk of bowel cancer. A typical portion of fish is around 100g.

The researchers concluded: “Consumption of fish appears to reduce the risk of colorectal (bowel) cancer and should be encouraged as part of a healthy diet.”

The team said fatty and oily fish is an extremely rich source of long-chain n-3 polyunsaturated fatty acids (n-3 LC-PUFA), which are believed to have a protective effect in the body and prevent inflammation. Non-fatty fish also contains these particular fatty acid compounds.

However, shellfish appeared to have no effect on the risk of bowel cancer.

Over the next 15 years, 6,291 people involved in the study were found to have developed bowel cancer.

The study was published in the journal Clinical Gastroenterology and Hepatology and was funded by the World Cancer Research Fund (WCRF) in order to help strengthen its advice to the public on bowel cancer.

Dr Marc Gunter, the lead researcher from the IARC, said that the findings demonstrate that eating fish should be encouraged as part of a healthy diet.

However, Gunter highlighted one downfall of the study was that dietary data collected from participants did not include information on fish oil supplement intake.

“This unmeasured fish oil supplementation may also have an effect on bowel cancer, so further studies will be needed to see if fish or fish oil influence bowel cancer risk,” Gunter said.

Previous research by the WCRF has found only limited evidence that consuming fish may be linked with a reduced risk of bowel cancer.

Dr Anna Diaz Font, head of research funding at the WCRF, said: “This large study adds to the scientific evidence suggesting that consuming fish could reduce the risk of bowel cancer.”

Font went on to explain that while the biological reasons by which fish consumption potentially lowers risk are not fully understood, 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”.

Lisa Wilde, director of research and external affairs at Bowel Cancer UK, welcomed the study but called for further research.

“Making simple changes to your lifestyle can help stack the odds against bowel cancer,” Wilde said.

“Including wholegrains, fibre and fish in your diet, being of a healthy body weight, having regular physical activity, avoiding processed meats and limiting red meat, can all make a real difference.”

Bowel cancer is the fourth most common cancer in the UK and has the second highest death rate of all cancers.

Around 42,000 people in the UK are diagnosed with bowel cancer every year, Bowel Cancer UK states.

This equates to around 115 new cases of bowel cancer every day.

Symptoms of bowel cancer can include a change in your bowel habits, blood in stool, weight loss, pain in your abdomen or back, fatigue and feeling as though you need to strain your back package, even after going to the toilet, Cancer Research UK outlines.