Renowned American chef Albert Stockli once touted the virtues of parsley by calling it, “the jewel of herbs, both in the pot and on the plate.” The common herb may be more than a garnishment for your next meal; it’s a potent weapon in the fight against breast cancer.

That little curly herb stops certain breast cancer tumor cells from multiplying and growing, according to a new University of Missouri study published in Cancer Prevention Research.

Dr. Salman Hyder, the Zalk Endowed Professor in Tumor Angiogenesis and Biomedical Sciences Professor conducted the study. He believes this finding could impact women who are taking certain synthetic hormone replacement therapy (HRT).

An estimated six to 10 million women in the U.S. currently receive HRT. Researchers acknowledge certain synthetic hormones used in HRT, including a progestin called medroxyprogesterone acetate or MPA, accelerate breast tumor development.

In the study, Hyder exposed rats to MPA. Some of the study animals were exposed to apigenin, a common compound most prevalently found in parsley and celery, and in lesser amounts in apples, oranges and nuts. The rats treated with apigenin developed fewer tumors and experienced significant delays in tumor formation compared to rats denied apigenin.

How much apigenin is beneficial for humans has not yet been determined since the compound is not absorbed efficiently into the bloodstream, Hyder said.

“However, it appears that keeping a minimal level of apigenin in the bloodstream is important to delay the onset of breast cancer that progresses in response to progestin, such as MPA,” Hyder said in a written statement.

“It’s probably a good idea to eat a little parsley and some fruit every day to ensure the minimal amount. Of course, you should always check with your doctor before making any major changes to your diet or lifestyle,” he said.

When tumors develop in the breast in response to MPA, the synthetic hormone stimulates new blood vessels to form within the tumors. Those blood vessels supply the tumors necessary nutrients to grow and multiply.

In the study, Hyder found apigenin effectively blocked new blood vessel formation thereby delaying — in some cases stopping — the tumor development. The study also showed apigenin reduced the overall number of tumors, but didn’t stop the initial formation of breast cancer cells.

The next phrase of studies should include human clinical trials to determine the appropriate dosage, and to address any health and safety issues that might exist, Hyder said.

He notes apigenin supplements are available in the health food section of many stores.

Lynette Summerill is an award-winning writer who lives in Scottsdale, Arizona. In addition to writing about cancer-related issues for EmpowHER, her work has been seen in newspapers and magazines around the world.