Oily fish may reduce risk of death from bowel cancer
Just a few mouthfuls of oily fish a day could reduce the risk of bowel cancer patients dying from the disease, a new study suggests.
Patients appeared to cut their chance of death by up to 70 per cent just be upping their intake of marine omega-3 fatty acids, found in fish like sardines and mackerel.
It is thought that omega-3 can suppress tumour growth and block blood supply to cancer cells.
Crucially, even small amounts seemed to make a difference. A normal portion of oily fish contains around 1.8g of omega-3 but just 0.3g a day lowered the risk of death within 10 years of diagnoses by 41 per cent.
It suggests that just a few mouthfuls a day, or one or two portions a week might be beneficial.
Those people who upped their intake by a further 0.15g after diagnosis lowered their risk by 70 per cent. However those who cut the amount of fish raised their risk of death by 10 per cent.
Although the researchers say that the findings were observational and no firm conclusions can be drawn, they conclude that it provides the first evidence that omega-3 fatty acids could impact bowel cancer survival.
“If replicated by other studies, our results support the clinical recommendation of increasing marine omega-3 fatty acids among patients with bowel cancer,” said lead researcher Dr Andrew Chan, Clinical and Translational Epidemiology Unit, Massachusetts General Hospital, Boston.
The researchers looked at nearly 200,000 people from two large cohort studies which monitored diet and cancer prevalence.
Regular intake seemed to be especially beneficial for those who were tall, had a BMI below 25, and who did not take a regular aspirin, who lowered their risk of death by 85 per cent, 90 per cent and 88 per cent respectively.
Most of those with regular intakes of fish oil ate fish rather than supplements, so it is unknown if the link would also work for capsules.
Dr Alister McNeish, Lecturer in Pharmacology at the University of Reading said: “The paper provides interesting and robust evidence that high omega-3 intake is associated with improved colorectal cancer survival in those who have been diagnosed with the condition.
“Omega-3 fish oils are generally considered to improve blood flow so the idea that fish oils reduce tumour blood flow seems paradoxical.”
Prof Tom Sanders, Professor emeritus of Nutrition and Dietetics, King’s College London, said: “This is an observational study and it is not possible to attribute the lower risk of bowel cancer specifically to omega -3 fatty acids because vitamin D may also have protective effects against colorectal cancer.
“This study provides no support of taking omega-3 supplements but does support to the notion that eating oily fish once/twice a week is good for health especially if it replaces red and processed meat.”
The research was printed in the BMJ journal Gut.