Fish Oil Helps Prevent Weight and Muscle Loss in Cancer Patients

Roxanne Nelson

March 01, 2011

March 1, 2011 — Supplementation with fish oil might help prevent muscle wasting and weight loss in cancer patients undergoing chemotherapy.

In a small study of 40 patients newly diagnosed with nonsmall-cell lung cancer (NSCLC), those who received fish oil supplements maintained weight, muscle mass, and muscle quality.

The study, published online February 28 in Cancer, found that about 69% of the patients who took fish oil gained or maintained muscle mass. In comparison, only 29% of patients in the control group maintained muscle mass; as a group, they lost an average of 1 kg of muscle.

"Fish oil may prevent loss of weight and muscle by interfering with some of the pathways that are altered in advanced cancer," said senior author Vera C. Mazurak, PhD, assistant professor in the Department of Agricultural, Food & Nutritional Science at the University of Alberta in Edmonton, Canada.

"This holds great promise because currently there is no effective treatment for cancer-related malnutrition," she said in a statement.

Dr. Mazurak pointed out that fish oil is safe and nontoxic with virtually no adverse effects, and might benefit patients with other types of cancer or chronic diseases that are associated with malnutrition. It might also be beneficial to elderly individuals who are at risk for muscle loss.

However, in their paper, the authors point out that previous results with fish oils in cancer patients have been mixed. Three large phase 3 trials failed to demonstrate a clear benefit of eicosapentaenoic acid (EPA) on either body weight or lean tissue in cancer patients. But other studies have been positive, and have shown that supplementation with more than 2 g/day of EPA could stabilize weight loss, attenuate lean tissue wasting, and increase survival in patients with advanced cancer.

There have also been numerous studies that reported other health benefits associated with fish oil supplementation. One study, for example, found that fish oil supplementation was associated with a lower risk for breast cancer in postmenopausal women. There is also extensive evidence that fish oils might prevent and treat many aspects of cardiovascular disease.

Weight and Muscle Maintained

In the current study, Dr. Mazurak and colleagues hypothesized that EPA derived from fish oil might help patients maintain or gain muscle. They randomized the 40 newly diagnosed NSCLC patients to receive either EPA 2.2 g/day (n = 16) or standard care (no intervention; n = 24) while undergoing first-line chemotherapy.

The skeletal muscle and adipose tissue of the participants were measured using computed tomography images, and weight was recorded at baseline and throughout chemotherapy. The average time on the study was 10 weeks, and was comparable between the 2 cohorts.

The authors designed the current trial as an open-label study to "avoid the challenges of previous studies," such as contamination between treatment groups and poor compliance.

Patients who received standard care lost an average of 2.3 km, whereas patients who received fish oil were able to maintain their weight. Less than a third of the control group maintained or gained weight while undergoing chemotherapy (range, 0.0 to 4.6 kg), whereas more than two thirds of the fish oil group maintained or gained weight (range, 0.0 to 6.7 kg).

Patients with the greatest increase in plasma EPA concentration after supplementation had the greatest gains in muscle (r2 = 0.55; P = .01). In the control group, there was evidence of loss of skeletal mass, with some patients losing up to 5.2 kg of muscle from baseline to the end of treatment.

Overall treatment response was similar between the 2 groups. Overall, 69% of the fish oil group (n = 11) had stable disease or achieved a partial response after chemotherapy, compared with 67% of the control group (n = 16).

The fish oil was well tolerated, and no serious adverse events were reported.

"The use of fish oil as a therapy to prevent body composition changes in patient populations who are at an increased risk of developing cancer cachexia merits further investigation," the authors conclude.

The study was funded by a Canadian Institute of Health Research Grant and by a Queen Elizabeth II Graduate scholarship.

Cancer. Published online February 28, 2011. Abstract


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