Natural Plant Compound Cuts Ovarian Cancer Risk
November 10, 2009
by David Gutierrez, staff writer
High intake of foods containing the natural plant compound apigenin might decrease a woman’s risk of ovarian cancer, researchers from Brigham and Women’s Hospital and Harvard Medical School have found.
Apigenin is a class of flavonoid, a phytonutrient (plant compound) family known for its high antioxidant activity. Antioxidants are renowned for removing cell-damaging free radicals from the body, thereby reducing the symptoms of aging and the risk of chronic disease such as cancer and heart disease.
Foods high in apigenin include celery, parsley, tomato sauce and red wine. The compound is widely believed to be safe when consumed in plant foods, with no toxic or mutagenic effects.
In a study funded by the National Cancer Institute and the National Institutes of Health, and published in the International Journal of Cancer, researchers gave questionnaires to 1,141 ovarian cancer patients and 1,183 women of similar age to assess the content of their diets over the course of one week. The average participant age was 51. Women with ovarian cancer were more likely to be heavier and have a higher daily calorie intake, with a less healthy diet than the healthy women.
The researchers used the questionnaires to calculate the participants’ intake of five different, common flavonoids: apigenin, kaempferol, luteolin, myricetin and quercetin. The bulk of these antioxidants in the women’s diets came from tea, red wine, apples, blueberries, celery, kale, lettuce, oranges and tomato sauce.
Higher intake of certain rich-rich foods such as cauliflower, raisins and tomato sauce was associated with a decreased risk of ovarian cancer, though this correlation was not statistically significant. There was no correlation between total flavonoid consumption and cancer risk after adjusting for known cancer risk factors such as age, physical activity, use of oral contraceptives, and history of childbirth, breastfeeding and tubal ligation. There was also no correlation between cancer risk and any of the flavonoids except for apigenin.
Women with the highest apigenin intake, however, had a “borderline significant” 28 percent lower risk of ovarian cancer than women with the lowest intake, after adjusting for other risk factors and intake of the other four flavonoids.
Ovarian cancer is among the most lethal forms of cancer in women. There are 20,000 new cases in the United States each year, leading to 15,000 deaths per year. According to the Ovarian Cancer National Alliance, the disease affects one in 69 women and kills one in 95.
This study is not the first to indicate a connection between apigenin and decreased cancer risk. Previous research has found that apigenin decreases the structural stability and inhibits the expression of a protein that is involved in the migration of ovarian cancer cells to other parts of the body. It has also been more directly observed to interfere with the movement of ovarian cancer cells. Apigenin has also been shown to inhibit the expression in ovarian cancer cells of a protein linked to the development of blood vessels in tumors, as well as overall tumor growth.
Other studies have found that apigenin inhibits the growth of some breast cancers and may induce programmed cell death. Higher intake of other flavonoids has also been shown to reduce the risk of ovarian cancer.
The researchers in the current study speculated that flavonoids may also help reduce ovarian cancer risk simply by functioning as antioxidants, eliminating free radicals that have been linked to DNA damage. More specifically, apigenin and other flavonoids might inhibit the effect of estrogen in the body either by reducing circulating levels or by blocking estrogen receptors.
“These mechanisms could be important in inhibiting ovarian carcinogenesis, due to the estrogen-rich environment within the ovaries and the proliferative effect of estrogen on ovarian epithelial cells,” the researchers wrote.