Cancer

Cancer

Treatment and Prevention

Low Dose Fish Oil Supplementation Inhibits Tumor Growth

A safe, simple clinical intervention to slightly increase the amount of omega-3 fatty acid nutrients in the diet may pack a powerful clinical wallop, helping to fight the growth of cancerous tumors and reducing negative side effects associated with chemotherapy.

In an experimental study, researchers from the University of Texas Health Science Center recently evaluated the effect of dietary fat consumption on the growth of cancer tumors in laboratory mice. The tumors had formed in response to the proliferation of estrogen-dependent breast cancer cells.

One group of mice was fed a diet containing 5% corn oil. The other group consumed a diet with 2% corn oil and 3% fish oil concentrate (34% EPA, 24% DHA, and other omega-3 fatty acids). The researchers purposely chose to study supplementation with a relatively small amount of fish oil, one that translated into just 7% of total calories consumed per day, because this proportion represents an amount that humans could easily incorporate into their diets. (For a human eating 1800 calories a day, this equals about 14 g of fish oil per day).

Over the next few weeks, investigators regularly tracked tumor growth in the mice, evaluating clinical impact in response to fish oil supplementation as well as to treatment with doxorubicin (DOX), a drug commonly used in chemotherapy. After just two weeks, even this modest amount of fish oil raised levels of omega-3 (EPA) in the cell membranes of the livers and tumors of the mice. And after just five weeks, low dose omega-3 supplementation was deemed just as effective in slowing tumor growth as DOX chemotherapy.

While previous experimental studies have reported that omega-3 fatty acids markedly suppress tumor growth, these new results indicate that a significant anti-tumor effect may be achieved at lower doses, over shorter intervention periods.

An important synergistic effect was also found. When fish oil supplementation was combined with DOX, tumor growth was slowed even further - without increasing toxic side effects of chemotherapy. In fact, adding fish oil to the diet reduced weight loss associated with DOX, helping to avert this negative side effect of chemotherapy.

Overall, this evidence suggests that fatty acid supplementation, when sustained between cycles of cancer chemotherapy, "may slow the growth of residual tumor…and aid patient recovery…" the researchers suggested.

Whatever its exact mechanisms, fish oil appears to be a safe and promising adjunct treatment to suppress tumor growth and reduce chemotherapy side effects, they observed. They recommended that clinical trials with cancer patients be undertaken to further study the potential clinical benefits of supplementation.

Source: Hardman WE, Avula CPR, Fernandes G, Cameron IL. Three percent dietary fish oil concentrate increased efficacy of doxorubicin against MDA-MB 231 breast cancer xenografts. Clin Can Res 2001;7:2041-2049.