Wednesday Nov 13, 2013 (foodconsumer.org) -- Epidemiological studies have suggested that eating omega 3 fatty acids including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) found in cold water fish and fish oil may reduce the risk of various cancers.  A diet supplemented with flaxseed, which is high in  alpha-linolenic acid (ALA) can provide a similar protective effect against ovarian cancer, according to a new study in Prostaglandins, Leukotrienes and Essential Fatty Acids (PLEFA).  In humans, ALA can be converted into EPA and DHA.

Dale Buchanan Halesa from Department of Physiology, Southern Illinois University at Carbondale School of Medicine in Carbondale, IL, USA and colleagues conducted the study and found flaxseed supplementation reduced the severity of ovarian cancer in laying hens that are commonly found to develop the type of disease.  And the study also found that the reduction in the cancer severity was realized by inhibiting the ovarian Prostaglandin E2 (PGE2) - the most pro-inflammatory ecoisanoid which is assumed to promote the development of ovarian cancer.

For the study, white Leghorn hens were fed a diet supplemented with 10% flaxseed or a standard diet as control for one year.   At the end of the dietary intervention, the severity of ovarian cancer was assessed and some biochemical parameters were measured.

The study showed that the long-term flaxseed supplementation significantly reduced late stage ovarian tumors in the flaxseed fed laying hens, compared with the controls.  This reduction was correlated with a decrease in concentrations of PGE2 and expression of COX2, which is the enzyme that helps produce PGE2 in ovaries of flaxseed fed laying hens.  

The researchers concluded "Our findings suggest that the flaxseed-mediated reduction in the severity of ovarian cancer in hens is correlated to the reduction in PGE2 in the ovaries of flaxseed-fed hens."

 "These findings may provide the basis for clinical trials of dietary intervention targeting prostaglandin biosynthesis for the prevention and treatment of ovarian cancer."

Ovarian cancer is a cancer in the ovaries, part of the female reproductive system where eggs and female hormones are produced.  Ovarian cancer is not as common as breast cancer, but it is more lethal than breast cancer.

An estimated 22,280 American women were diagnosed with ovarian cancer in 2012 and the disease killed 15,500 women in the same year.

Ovarian cancer symptoms may not show up in every patient in early stages, which is why it is hard to diagnose the cancer early.  Possible ovarian cancer symptoms include a heavy feeling in the pelvis, pain in the lower abdomen, vaginal bleeding, weight gain or loss, abnormal periods, and unexplained back pain, gas, nausea, vomiting and loss of appetite, according to National Cancer Institute.

Because it is hard to diagnose and treat ovarian cancer, prevention is important.  In addition to flaxseed, which is high in phytoestrogens or lignans, other possible foods or dietary supplements that may help prevent the disease include high vitamin D, green tea, fruit and vegetables (boosting ovarian cancer survival), flavonoids, ginger, ginkgo biloba (ginkgolides), low fat diet, onion and garlic (allium vegetables). (David Liu, PHD)