Ingredients in oily fish may protect against cancer risk

A team of investigators from Leeds University examined the impact of omega-3 polyunsaturated fatty acid on people with a rare inherited condition believed to be responsible for about one in 100 bowel cancers.

They uncovered a significant reduction in pre-cancerous growths during a six-month trial of the omega-3 preparation in people who suffer from the condition known as familial adenomatous polyposis (FAP).

Those who were not given the treatment saw a 10 per cent increase in the number of growths, compared to a 12 per cent fall in the other group. The size of growths went up by 17 per cent in the non-treated group compared to a 12.5 per cent fall in those taking the treatment.

The scientists say further research will be needed to see if products derived from oily fish, such as salmon, mackerel and herring, could help prevent non-inherited bowel cancer which affects 37,000 people each year in the UK.

But early evidence suggests it could be as effective and safer than existing drug treatments for those prone to inherit the condition.

Prof Mark Hull, who led the study, said: "There is definitely a clinical need for an effective, preventative therapy that is both safe and well tolerated as the existing drug therapy for FAP can be associated with an increased risk of heart attack in older individuals.

"A safe and effective drug therapy may reduce the number of invasive check-up procedures, which can be unpleasant and always involve a small amount of risk."

He said the omega-3 preparation given to patients delivered about four times as much beneficial polyunsaturated fatty acid per day as from eating two to three portions of fish a week.

"The drug is also designed to be released into the small intestine, minimising nausea and halitosis often associated with taking over-the-counter fish oil supplements," he added.

Further research will now be needed to find out if the new preparation is a safe and effective treatment for the large number of patients who are found to have asymptomatic bowel growths and who are at increased future risk of recurrence and bowel cancer.

But the researchers say that omega-3 preparations are generally safe and even good for cardiovascular health and could be especially suitable for older patients who are at greater risk of bowel cancer and heart disease.

The research is published today in the journal Gut.