Fish Oil Helps Cancer Patients Maintain Muscle Mass
Fish oil supplements may help prevent weight and muscle loss during chemotherapy according to results from a small open-label study.
Involuntary weight loss among advanced cancer patients is common. This wasting is a major contributor to poor treatment response, functional decline, and reduced survival.
Vera C. Mazurak, PhD, of the University of Alberta in Edmonton, and colleagues reported the findings of their small study online February 28, 2011 in the journal Cancer.
Forty patients with nonsmall cell lung cancer receiving 10 weeks of chemotherapy completed the study. There were 16 in the fish oil group who were given 2.2 g of eicosapentaenoic acid (EPA) each day. There were 24 patients in the standard of care (SOC; no intervention) group who received no fish oil.
Skeletal muscle and adipose tissue were measured using computed tomography images. Blood was collected and weight was recorded at baseline and throughout chemotherapy.
The study found that those who started taking fish oil when they began chemotherapy actually gained 0.5 kg (1.1 lbs) whereas those receiving only the SOC lost 2.3 kg (5.1 lbs) by the end of their chemotherapy treatments (P
Muscle mass rose or stayed the same for 69% of patients taking the fish oil supplements, compared with only 29% among controls in the small open-label trial.
Fish oil was well tolerated in the study without any serious adverse events.
The researchers note the results didn't appear to be due to differences in tumor progression between the groups as treatment response was similar between the two.
While larger trials are needed to confirm the benefit, the researchers suggested that their findings were encouraging given that the effects of fish oil over about 10 weeks of chemotherapy were seen despite patients presenting with a mean weight loss of 6.3% over the prior six months.
Mazurak and co-authors noted "Patients receiving active treatment may represent an opportunity for timely nutritional intervention because side effects from chemotherapy such as nausea, vomiting, dysphasia, and anorexia often are disabling, and may impact on body weight and composition."
They cautioned that the maintenance of body composition seen in the fish oil group couldn't be entirely attributed to the supplements because other trials have reported improvements in weight during chemotherapy.
While the authors acknowledged that the open-label design may have limited results, they argued that the outcomes were strengthened by the inclusion of a larger reference group (n=104) of NSCLC patients.
Many fish oil supplements contain EPA and docosahexaenoic acid (DHA), which can be synthesized within the body using EPA. The capsules often contain 1000 mg with the recommended dose being 1-3 capsules per day.
EPA and DHA both belong to a category of molecules known as omega-3 fatty acids, which also includes alpha-linolenic acid (ALA). The human body is not able to synthesize omega-3 fatty acids on its own.
ALA is found in many common vegetable oils and fruit seeds, including kiwifruit seeds and flaxseed. Cancer patients often have poor appetites. Chemotherapy can cause nausea, further loss of appetite, or affect the patient’s taste.
Murphy RA, et al "Nutritional intervention with fish oil provides a benefit over standard of care for weight and skeletal muscle mass in patients with nonsmall cell lung cancer receiving chemotherapy" Cancer 2011; DOI: 10.1002/cncr.25709.