Goji is a commercial name applied to two species of wolfberries, Lycium barbarum and L. chinense. Goji berries and juice are sold as dietary supplements for their purported anti-aging and health-promoting benefits. According to a January 2010 review in "Planta Medica," goji has been used for centuries as a food and medicinal agent by indigenous peoples in East Asia. However, like many herbal remedies, goji has demonstrated a tendency to interact with Coumadin. If you take Coumadin, consult with a medical professional before taking goji or any other herbal preparation.
Warfarin
Coumadin, otherwise known as warfarin, is a drug prescribed by physicians to inhibit blood clotting. Certain medical conditions -- artificial heart valves, abnormal heart rhythms, autoimmune diseases, cancer and others -- increase your risk for producing clots inappropriately. These clots can then block blood vessels or travel to organs where they cause serious damage or even death. Warfarin interferes with the production of proteins that coagulate your blood and it prolongs your bleeding time. Warfarin's therapeutic effects are measured with a prothrombin time (PT), and international normalized ratio (INR).
Polysaccharides
Many of goji's therapeutic properties are attributed to its content of polysaccharides, which are complex sugar molecules naturally produced within the plant. Scientists at the University of Hong Kong's Eye Institute report that goji's polysaccharides modulate immune function, reduce the side effects of chemo- and radiotherapy, protect your liver, lower blood glucose levels and act as antioxidants. These properties have understandably caught the attention of scientists and consumers alike, but goji's constituents have been linked to increased PTs and INRs in patients taking warfarin.
Interactions
Warfarin frequently interacts with dietary supplements and medications. Because it shares common metabolic pathways with many other drugs and plant-based compounds, warfarin's breakdown and elimination can be slowed or accelerated by agents that either compete with the drug for metabolism or that "up-regulate" the enzymes that degrade it. This changes the amount of warfarin in your bloodstream. Several cases of increased bleeding tendencies have been noted in patients who took goji and warfarin concurrently. The October 2001 issue of the "Annals of Pharmacotherapy" described a case where a woman whose PT and INR nearly doubled after she consumed a tea made from goji berries.
Considerations
Like many herbal preparations, goji appears to interact with Coumadin, or warfarin, leading to an increased PT and INR. This confers a higher risk for serious bleeding. When you consume substances that interact with warfarin on a daily basis, your doctor may be able to adjust your warfarin dosage to compensate for the interaction. However, many physicians ask their patients who take warfarin to avoid those items that interact with this drug. If you take Coumadin, ask your doctor if goji is appropriate for you.
References
- "Planta Medica"; Goji (Lycium Barbarum and L. Chinense): Phytochemistry, Pharmacology and Safety in the Perspective of Traditional Uses and Recent Popularity; O. Potterat; January 2010
- "PLoS One"; Lycium Barbarum Polysaccharides Reduce Neuronal Damage, Blood-Retinal Barrier Disruption and Oxidative Stress in Retinal Ischemia/Reperfusion Injury; S. Li, et al.; January 2011
- "The Annals of Pharmacotherapy"; Possible Interaction Between Warfarin and Lycium Barbarum L.; A.Y. Lam, et al.; October 2001
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