Fatty acids can prevent chemotherapy drugs from working, researchers in the Netherlands have found.

In a study, published in the journal Cancer Cell, scientists identified two fatty acids which, in minute quantities, can cause tumours to become immune to treatment.

The fatty acids, known as platinum-induced fatty acids, can be found in fish oil supplements and are produced by stem cells in the blood.

Tests on mice with tumours under skin showed that the animals became insensitive to cisplatin, a form of chemotherapy, once they had been injected with the fatty acids.

Professor Emile Voest, a medical oncologist at University Medical Center Utrecht said, “Whilst waiting for the results of further research, we currently recommend that these products should not be used whilst people are undergoing chemotherapy.

“Where resistance to chemotherapy is concerned, we usually believe that changes in the cancer cells themselves have occurred. Now we show that the body itself secretes protective substances into the blood that are powerful enough to block the effect of chemotherapy.”