Flaxseed, a high-fiber and omega 3-fatty acid-rich compound, appears to halt the formation of prostate tumors, according to a study led by Duke University Medical Center researchers.

The seed, which is similar to a sesame seed and belongs to a group of compounds called lignans, may be able to interrupt events that lead cells to divide irregularly and become cancerous, concluded the study.

“Our previous studies in animals and in humans had shown a correlation between flaxseed supplementation and slowed tumor growth, but the participants in those studies had taken flaxseed in conjunction with a low-fat diet,” said Wendy Demark-Wahnefried, a Duke School of Nursing researcher and lead investigator on the study, in a news release.

Demark-Wahnefried said this most recent study showed that flaxseed alone provided prostate cancer-fighting benefits.

For the study, researchers examined the effects of flaxseed supplementation on men who were scheduled to undergo prostatectomy—surgery for the treatment of prostate cancer. The men took 30 grams of flaxseed daily for an average of 30 days prior to surgery.

Men taking flaxseed alone or in conjunction with a low-fat diet, were compared to men assigned to just a low-fat diet, as well as to men in a control group, who did not alter or supplement their daily diet. Each group was made up of about 40 participants.

Once the men’s tumors were removed, the researchers looked at tumor cells under a microscope to determine how quickly the cancer cells had multiplied. Men in both of the flaxseed groups had the slowest rate of tumor growth, Demark-Wahnefried said.

Study participants took the flaxseed in a ground form because, in its whole form, it has an indigestible seed coat, she said. Participants elected to mix it in drinks or sprinkle it on food, such as yogurt.

“The results showed that the men who took just flaxseed as well as those who took flaxseed combined with a low-fat diet did the best, indicating that it is the flaxseed which is making the difference,” Demark-Wahnefried said.

Researchers believe that, as a source of omega 3-fatty acids, flaxseed can alter how cancer cells lump together or cling to other body cells, which are factors in how fast cancer cells proliferate, Demark-Wahnefried said. The researchers also suspect that lignans may have antiangiogenic properties, meaning they are able to choke off a tumor’s blood supply, stunting its growth.