Fish oil supplements could dramatically improve the lives of some cancer patients, according to a study.
Fish like mackerel are a good source of Omega 3 oils
British researchers say fish oils may prevent cachexia - the severe wasting and weight loss associated with some types of advanced cancer.
It can cause illness and contribute to the death of these patients because of its effects on metabolism and appetite.
Writing in the journal Gut, the researchers said fish oil supplements may be able to reverse the weight loss.
Professor Kevin Fearon and colleagues at Edinburgh Royal Infirmary studied 200 patients with pancreatic cancer, who tend to suffer most from cachexia.
They were divided into two groups - 105 were given a high calorie, high protein supplement and 95 were given a high calorie, high protein supplement with omega 3 essential fatty acid and vitamins E and C.
Omega 3 essential fatty acids are found in fatty fish, such as salmon and herring.
Each group was asked to drink two cans a day of their assigned supplement for eight weeks. In the case of the second group, this equated to 2.2g of omega 3 fatty acid per day.
Before the study started, patients had lost on average 17% of their body weight and were losing 3kgs of weight a month.
By the end of the study, all of the patients had stopped losing weight.
However, the researchers found that not all patients had drunk their two cans each day. On average, they consumed 1.5 cans daily.
Further analysis showed that those patients who had consumed most of their drinks on a regular basis gained the most.
However, this was only found in patients whose supplements included omega 3 fatty acids.
While these patients did not live longer compared with those in the first group, their quality of life was better.
"If taken in sufficient quantity only the n-3 (Omega 3 fatty acid enriched energy and protein dense supplement results in net gain of weight, lean tissue and improved quality of life."
The researchers acknowledged that further study is needed but they added that the findings suggest that fish oils could be used to treat cancer patients with cachexia.
Robert Grimble, professor of human nutrition at the University of Southampton, said other studies also needed to examine whether Omega 3 supplements could help patients with other forms of cancer.
Writing in an accompanying editorial, he said: "It remains to be seen whether this effect is achieved by an anti-inflammatory mechanism and whether cancers in which cachexia is not as severe as in pancreatic cancer will respond favourably to similar nutritional therapy."