Grapefruit Seed Extract Liquid Concentrate Side Effects

Grapefruit seed extract liquid concentrate, also known as GSE, is used internally and externally to eliminate bacteria. It's also added to cosmetics and other products as a preservative. While GSE is touted as a natural product, it actually undergoes a chemical conversion in a laboratory before being packaged. In addition, grapefruit seed extract liquid concentrate contains synthetic ingredients, which are associated with several side effects. Therefore, consult with your health care practitioner before using GSE internally.

Toxicity

One of the potential side effects of grapefruit seed extract liquid concentrate is toxicity from benzethonium chloride, a synthetic chemical added to the extract for its antimicrobial properties. In 1994, the U.S. Food and Drug Administration published a guide, titled "Tentative Final Monograph for First Aid Antiseptics," which states that this chemical is regarded as safe in concentrations between 0.1 and 0.2 percent. However, the U.S. Department of Agriculture later analyzed several samples of liquid GSE and found that eight of them contained concentrations of benzethonium chloride that were greater than 8 percent. Large doses of benzethonium chloride may cause vomiting, seizures, shock and coma. The authors of this study expressed deep concern over these findings since liquid GSE concentrate is marketed as safe for internal use.

Cancer Risk

Gary Takeoka, lead researcher in the above-referenced USDA study, also reported that the preservative properties attributed to grapefruit seed extract liquid concentrate are actually due to the presence of synthetic preservatives, namely methylparaben. According to a study published in the July-August 2005 issue of the Journal of Applied Toxicology, methylparaben, as well as other metabolites of paraben esters, exhibit estrogenic effects in the body. While the study authors noted that animal-based studies previously demonstrated a link between exposure to parabens and certain cancers, they were also able to conclude that methylparaben exerts estrogenic activity in human breast cancer cells.

Drug Interactions

In a study published in the June 2007 issue of the European Journal of Clinical Pharmacology, a team of Swedish researchers reported that benzethonium chloride present in GSE interferes with the function of two digestive enzymes known as CYP2C9 and CYP3A4. These enzymes are classified as cytochrome P450 enzymes, which are involved in the metabolism of toxins as well as medications. This study determined that the disruption of the normal activity of these enzymes produced from the ingestion of GSE containing benzethonium chloride increases the effects of anticoagulant drugs, such as warfarin.