Can Reduce Risk of Breast, Ovarian and Endometrial Cancer according to a study conducted at the University of California, Berkeley.
A high level of estradiol has been shown to raise the risk of certain cancers. Prior studies have shown that Japanese women, who eat more of these types of brown seaweed than most Western women, have lower levels of serum estradiol. This lower level of serum estradiol is thought to contribute to their lower rates of breast, endometrial and ovarian cancers.
Although the UC Berkeley researchers have not yet clearly determined why kelp family seaweeds in the diet reduce serum estradiol levels, Christine Skibola, lead author of the study, stated "one possibility is that the kelp may be acting as an estrogen antagonist by preventing estradiol from binding with its estrogen receptors."
The study tested the impact of dietary kelp on estradiol levels. After four weeks of eating 35 milligrams of kelp (approximately 1/2 ounce) a day, estradiol levels in laboratory animals were reduced by 25%.