"This study opens up a new avenue for research leading to cancer preventive agents," said Martyn Smith, UC Berkeley professor of environmental health sciences and co-author of the study. "Kelp is a little studied nutrient, but there's good reason to look at it more closely."
These new results, to be published Feb. 2 in the Journal of Nutrition, shine a new light onto the Japanese diet. Prior studies have shown that Japanese women have longer menstrual cycles and lower serum estradiol levels than their Western counterparts, which researchers say may contribute to their lower rates of breast, endometrial and ovarian cancers. Scientists have been searching Asian diets for clues to the lower rates of cancer, with the lion's share of attention being given to soy.
"Brown kelp seaweed makes up more than 10 percent of the Japanese diet," said Christine Skibola, assistant research toxicologist at UC Berkeley's School of Public Health and lead author of the study. "Soy has gotten most of the attention, but our study suggests that kelp may also contribute to these reduced cancer rates among Japanese women."
The researchers say that the type of kelp used in this study, bladderwrack seaweed (Fucus vesiculosus), is closely related to wakame and kombu, the brown seaweeds that are most commonly consumed in Japan. Bladderwrack seaweed is the primary form of kelp sold in the United States. They say these study results support the need for more research on wakame and kombu.