Chemotherapy: Do Omega 3s Improve the Effects?

An improvement in the nutritional status of cancer patients undergoing chemotherapy can correspond to an improvement in prognosis. What role do Omega 3s play in this association? Can they enhance the effects of treatments? At what dosages? Here’s what we know on the topic.

Fish oil, a rich source of Omega 3 fatty acids, could help counteract weight loss during chemotherapy and improve the therapeutic efficacy of the treatment as well as the nutritional status of patients. 

This is suggested by the scientific literature: according to the authors of a 2023 meta-analysis published in Critical Reviews in Food Science and Nutrition, there is evidence that “the consumption of orally administered supplements enriched with Omega 3 polyunsaturated fatty acids exerts beneficial effects on nutritional status and clinical outcomes in patients undergoing chemo (radio) therapy.”

Their conclusions reinforce findings from previous systematic reviews on the topic; in fact, as early as 2015 a review published in Clinical Nutrition highlighted the “beneficial effects of Omega 3 fatty acid supplements in patients undergoing chemotherapy,” emphasizing that among these effects, “the most evident is the ability to preserve body composition.”

In this regard, eicosapentaenoic acid (EPA, one of the biologically active Omega 3s abundant in marine sources like fish oil) appears to help cancer patients prevent both loss of muscle mass and fat mass. This was shown in a study coordinated by Vera Mazurak at the University of Alberta (Canada), published in Cancer in 2011, which also suggests a possible dosage: 2.2 grams per day.

Omega 3 and cancer

Cancer patients often deal with increased levels of inflammation; moreover, chemotherapy further increases the production of molecules associated with inflammation (cytokines and prostaglandins) and reactive oxygen species, promoting a cascade of events that suppress immune functions.

Given their anti-inflammatory properties, Omega 3s emerge as potential allies against these phenomena. Additionally, these nutrients exhibit anti-proliferative, pro-apoptotic, and anti-metastatic actions useful against cancer. They may also exert antitumor effects by epigenetically regulating genes (i.e., without changing their sequence).

Numerous in vitro and in vivo studies suggest that EPA and the other marine-origin Omega 3 (docosahexaenoic acid - DHA) positively regulate the effects of anticancer treatments; furthermore, human trials suggest they may improve therapy outcomes by reducing risks and side effects.

Chemotherapy side effects: weight loss

Among possible side effects, weight loss is very common in cancer patients undergoing chemotherapy; moreover, prognosis is closely related to body composition.

Addressing malnutrition causing this wasting is essential to counteract fatigue and reduced quality of life accompanying treatment, which prevent patients from continuing therapies, consequently reducing life expectancy. 

An interesting aspect is the link between Omega 3 levels and loss of lean and skeletal muscle mass, which is greater in cancer patients with lower levels of these fats.

The study by Mazurak and colleagues demonstrated that the loss of muscle and fat tissue can be countered by taking 2.2 grams per day of EPA, offering a solution to malnutrition associated with chemotherapy. 

The research involved 40 patients, 16 of whom supplemented their diet daily with fish oil containing EPA throughout a chemotherapy cycle lasting about 10 weeks. The remaining 24 patients received only traditional care. 

During chemotherapy, researchers monitored muscle health through computed tomography, a technique allowing precise quantification of skeletal muscles. It emerged that although in the six months before the trial patients taking Omega 3 had lost an average of 6.3% body weight, fish oil supplementation allowed them to maintain their weight. Furthermore, about 70% of those who combined chemotherapy with EPA intake maintained or even increased their muscle mass. This effect was strongly correlated with Omega 3 fatty acid levels, so the higher the EPA increase in blood, the greater the muscle mass gain. 

Conversely, patients who did not supplement with fish oil lost an average of 2.3 kilograms during the 10 weeks of chemotherapy. Moreover, less than 30% of these patients maintained their muscle mass, and their one-year survival was 38.7% — significantly lower than the 60% observed in patients receiving fish oil supplementation.

Omega-3 against malnutrition

Mazurak highlighted how promising these results are: before this study, no effective treatment for cancer-associated malnutrition had been identified. Since fish oil was shown to prevent weight loss and muscle wasting by interfering with metabolic pathways altered in advanced cancer forms, researchers recommended daily Omega-3 supplementation with fish oil containing 2 grams of EPA to help cancer patients maintain weight and muscle mass during chemotherapy. 

The 2023 meta-analysis supported Mazurak’s optimism. Considering 22 published studies (totaling 1155 patients), its authors found a significant increase in body weight and body mass index following Omega 3 intake.

Omega 3 against inflammation and treatment toxicity

The 2015 review also showed anti-inflammatory effects of Omega 3 in chemotherapy patients. “Lower systemic inflammation levels, evaluated as C-reactive protein, were observed in all studies where measured,” explained the authors.

The 2023 meta-analysis confirmed these effects, reporting reductions not only in C-reactive protein but also in Tumor Necrosis Factor-alpha (TNF-α) and interleukin 6 (IL-6), two well-known pro-inflammatory molecules.

Finally, the 2023 meta-analysis noted a significant reduction in adverse event incidence, while the 2015 review also considered studies evaluating Omega 3 supplementation effects on the toxicity of antitumor treatments. One study highlighted the potential of Omega 3 in preventing peripheral neuropathy induced by the chemotherapy drug paclitaxel.

The authors emphasize how countering peripheral neuropathy would significantly improve patients’ quality of life and that, more generally, fish oil supplements are associated with better quality of life scores during chemotherapy.

How much Omega 3 during chemotherapy?

As mentioned, according to Mazurak et al., 2.2 grams of EPA per day are needed to prevent weight loss during chemotherapy — at least in the specific case considered (advanced non-small cell lung cancer).

The authors of the review published in Cancer also state that “considering clinical benefits, the optimal and safe dose for long-chain polyunsaturated Omega 3 fatty acids (EPA and/or DHA) is about 2 grams per day.”

“In the examined studies, fish oil was effective,” the experts clarify, adding that “EPA and/or DHA were rapidly incorporated into blood cells.” In this regard, it is worth remembering that Omega 3 levels in red blood cells (measured through the Omega-3 Index) are a widely used indicator of Omega 3 presence in the body.

References:

de Aguiar Pastore Silva J, Emilia de Souza Fabre M, Waitzberg DL. Omega-3 supplements for patients in chemotherapy and/or radiotherapy: A systematic review. Clin Nutr. 2015 Jun;34(3):359-66. doi: 10.1016/j.clnu.2014.11.005

Murphy RA, Mourtzakis M, Chu QS, Baracos VE, Reiman T, Mazurak VC. Supplementation with fish oil increases first-line chemotherapy efficacy in patients with advanced nonsmall cell lung cancer. Cancer. 2011 Aug 15;117(16):3774-80. doi: 10.1002/cncr.25933

Wang Y, Liu R, Chang M, Wei W, Guo Y, Jin Q, Wang X. Does omega-3 PUFA-enriched oral nutritional intervention benefit cancer patients receiving chemo (radio) therapy? A systematic review and meta-analysis of randomized controlled trials. Crit Rev Food Sci Nutr. 2023;63(18):3081-3096. doi: 10.1080/10408398.2021.1984199