Hop Leaves Discarded in Brewing May Fight Dental Diseases

WASHINGTON—Hops can do more than give beer its bitter taste and aroma. Scientists found that the hop leaves discarded when making beer could help fight cavities and gum disease, according to new research published in the Journal of Agricultural and Food Chemistry.

Lead researcher Yoshihisa Tanaka and colleagues from Tokyo University of Pharmacy and Life Sciences note that their earlier research indicates antioxidant polyphenols contained in the hop leaves (called bracts) could help fight cavities and gum disease. Extracts from bracts stopped the bacteria responsible for these dental conditions from being able to stick to surfaces, and they prevented the release of some bacterial toxins.

Every year, farmers harvest about 2,300 tons of hops in the United States, but the bracts are not used for making beer and are discarded. There is potentially a large amount of bracts that could be repurposed for dental applications, but very few of these compounds in bracts have been reported. Tanaka’s group decided to investigate what substances in hop leaves might cause healthful effects.

Using a laboratory technique called chromatography, the researchers found three new compounds. One already-known compound was identified for the first time in plants, and 20 already-known compounds were found for the first time in hops. The bracts also contained substantial amounts of proanthocyanidins, which are healthful antioxidants.

Utilizing the "leftovers" of different foods or beverages can provide a variety of benefits and help eliminate wasted products. For example, while most foods derived from coconut come from the actual nut, hearts of palm and a sweet palm sap with 16% sucrose also come from coconuts and can be used in different food products.