comfrey and Neoplasms

A current listing of potentially life-threatening, cancer-related dietary supplements (DSs; includes herbs) based on PubMed case reports was summarized in online tables that can now be updated continually to forewarn United States consumers, clinicians, and DS companies. Documented PubMed case reports were used to create a "Toxic Table" related to cancer (1966 to April 2016, and cross-referencing). Keywords included "herb" or "dietary supplement" combined with "cancer" as well as the specific herb "name" combined with "cancer" and sometimes "toxicity." Excluded were herb combinations (some exceptions), Chinese herb mixtures, teas of mixed herb contents, fungi (mycotoxins from molds and mushrooms), poisonous plants, self-harm, excessive doses (except vitamins/minerals), legal or illegal drugs, drug-herb interactions, and confounders of drugs or diseases related to cancer. Also included were a few foods related to cancer. Over the past 50+ years, PubMed case reports revealed an increased risk of cancer related to approximately one herb (guang fang ji), no dietary supplements (except those containing guang fang ji or aristolochic acid), and two foods (bracken fern, which is sometimes sold as an herbal supplement, and hot maté). This online "Toxic Table" can now be continually updated to assist researchers and clinicians in preventing serious adverse events from DSs related to cancer.

Topics: Aloe; Animals; Aristolochic Acids; Comfrey; Dietary Supplements; Drugs, Chinese Herbal; Ginkgo biloba; Herb-Drug Interactions; Humans; Neoplasms; Plant Extracts; Plant Preparations; Risk Factors; United States