Cranberry is one of the most popular herbal dietary supplements on the U.S. market, and is most often used for preventing and treating recurrent urinary tract infections. Currently, there are a variety of cranberry supplements on the market, and it is important to understand the compositional differences.

The supplements are made up of varying amounts of proanthocyanidins (PACs), cranberry compounds responsible for preventing bacterial adhesion in the urinary tract. Other important ingredients include whole cranberry fruit extracts and blends of cranberry juice extracts with cranberry fruit extracts with 3%-5% PACs, and also pure cranberry juice extracts with 21%-24% PACs. The higher the concentration of PACs, the more expensive the supplement.

Because cranberry extracts can be expensive, companies have been extracting lower-cost PACs from other sources such as peanut skins, grape seeds, mulberry fruit, hibiscus, calyx, black bean skin, and black rice, according to the American Botanical Council. Suppliers dilute or replace the cranberry PACs without labeling the behavior.

Ethnobotanist and herb industry consultant Thomas Brendler, and American Botanical Council Chief Science Officer and Botanical Adulterants Program Technical Director Stefan Gafner, PhD, have written a new article containing information on the growing range, production, and market importance of cranberry and cranberry extracts.

The bulletin also provides a list of known adulterants, potential therapeutic and safety concerns associated with the adulterated ingredients, and laboratory analytical approaches to detecting these ingredients.

“By publishing this bulletin on the adulteration of cranberry, it is our hope that more supplement manufacturers will be alerted to the unfortunate practices of some unscrupulous ingredient suppliers, thereby not only helping to protect the supplement manufacturers to ensure that they purchase properly authenticated cranberry ingredients, but also to help ensure that consumers are able to purchase authentic, reliable cranberry supplements.” says Mark Blumenthal, ABC founder and executive director, and Botanical Adulterants Program founder and director.