By David Liu, PHD

Tuesday Dec 4, 2012 (foodconsumer.org) -- Three studies reported below reveal that micronutrients particularly antioxidants derived from plant-foods may help prevent ovarian cancer.  An estimated 22,280 American women will be diagnosed with ovarian cancer in 2012 and the disease will kill 15,500 women in the same year, according to the U.S. National Cancer Institute.  It is hoped that these studies may give readers some idea about how to prevent ovarian cancer.

Dietary selenium cuts risk of ovarian cancer

A study led by D. Gifkins at The Cancer Institute of New Jersey, Robert Wood Johnson Medical School, New Brunswick, NJ and colleagues suggests that high intake of dietary selenium may help reduce risk of ovarian cancer.

The study published in BMC Cancer showed that women in the highest tertile of dietary selenium were 59% less likely to develop ovarian cancer, compared with those in the lowest tertile.

Oxidative stress is believed to be in the etiology of cancer and antioxidants can potentially play a protective role in the development of ovarian cancer.  In the study researchers examined the association between total antioxidant capacity (TAC) and individual antioxidants, including vitamin C, vitamin E, beta-carotene, selenium, lutein, and lycopene, and the risk of ovarian cancer.

The study involved 205 ovarian cancer cases and 390 controls without the disease aged 21 or older who resided in six counties in New Jersey.  Dietary intake of antioxidants were estimated based on data obtained through the Block food frequency questionnaire and the USDA Oxygen Radical Absorbance Capacity Database and the University of Olso's Antioxidant Food Databases.

Although selenium intake was inversely associated with ovarian cancer risk, dietary total antioxidant capacity and other individual antioxidants such as vitamin C, vitamin E, lutein and lycopene, were not found significantly associated with ovarian cancer.

The researchers concluded "This study found an inverse association between selenium consumption from food sources and ovarian cancer risk, while there was little evidence of an association with TAC or any of the other individual antioxidants. Additional research is needed to confirm these findings."

Vitamin B6 and methionine may reduce risk  of ovarian cancer

Holly. R. Harris from Brigham and Women's Hospital in Boston, MA, USA and colleagues published in a study in International Journal of Cancer suggesting that intake of vitamin b6 and methionine may help lower risk of ovarian cancer.

The study, intended to reveal the association between folate, methionine, vitamin b6 and vitamin b12 and risk of ovarian cancer, showed those in the highest quartile of intake of vitamin b6 and mehionine was 24% and 28% reduced risk for ovarian cancer, respectively, compared to those in the lowest quartile.

The study involved 1910 cases of ovarian cancer and 1989 controls from a case-control study conducted in eastern Massachusetts and New Hampshire from 1992 through 2008.

Folate, methionine, vitamin B(6) and vitamin B(12) are believed to be able to influence carcinogenesis because they play a role in the one-carbon metabolism pathway, which are critical for DNA synthesis, methylation and repair.  Low intake of these nutrients has already been associated with elevated risk of breast cancer, colon cancer and endometrial cancer.

The study also found the strongest association between vitamin b6 asn serous borderline and serous invasive subtypes of ovarian cancer, the risk was reduced by 51% and 26%, respectively among those who had the highest intake.

But folate was not linked to reduced risk of ovarian cancer.

Plasma carotenoids, retinol, and tocopherol may lower risk of ovarian cancer

A study published in Acta Obstet Gynecol Scand. suggests that maintaining high levels of plasma corotenoids, retinol, and tocopherol may help reduce the risk of ovarian cancer.

N.H. Jeoning from Kyung Hee University College of Medicine in Seoul, Korea and colleagues conducted study and found high levels of ss-carotene, lycopene, zeaxanthin, lutein, retinol, alpha-tocopherol, and gamma-tocopherol were all associated with reduced risk of ovarian cancer.

Specifically, women in the highest tertile for beta-carotene,  lycopene, zeaxanthin/lutein,  retinol,  alpha-tocopherol,  and gamma-tocopherol  were 88%, 91%, 79%, 55%, 77% and 72% reduced risk of ovarian cancer, respectively, compared with those in the lowest tertile.