Plant Products in Herbal Teas: Contraindications of Use

A cup of hot tea in mid-afternoon on a cold, snowy day warms spirit and body. Which tea to select? Black tea, green tea, or herbal tea? Nowadays, people are turning to herbal teas as alternatives to caffeinated beverages such as coffee, black and green tea, and cocoa). In the United States, the popularity of herbal tea consumption has increased significantly during the past few decades. Herbal teas are made up of mixtures of roots, leaves, seeds, barks, parts of shrubs, vines, and/or trees. Limited toxicological study of herbal teas has been conducted, meaning the safety of many of these products is unknown.

Notice the various colors of herbal tea packages in the tea section in grocery stores. Examples of colors include a yellowish-colored package for chamomile, a lemon-colored package emphasizing lemongrass, a lavender package focusing on lavender, a reddish-colored package highlighting ginger, a blueish/purple package highlighting berries, a greenish-colored package promoting mint, and a pinkish color for hibiscus and raspberry,

Herbal teas often include a combination of several plant products. This combination or combinations of plant products might include chamomile, lemongrass, peppermint, spearmint, rosehips, ginger, cinnamon, licorice root, pomegranate, stinging nettle, valerian, rooibos, valerian, luo han guo (a non-caloric sweetener to compete with other herbal sweeteners such stevioside), and hawthorn. Many of these plant products do have medicinal properties but it is important to know they also interact with prescription and over-the-counter drugs. Such interactions may decrease or increase the biological activity of medicinal drugs, meaning drugs are broken down too quickly or not quickly enough, thereby negatively affecting a person’s health.

The National Center for Complementary and Alternative Medicine (NCCAM) provides efficacy and safety information, fact sheets, resources, and tips for choosing or not choosing plant products included in herbal teas. The following is a selected list of herbs that carry warnings of use for people who have certain health conditions (particularly cardio-vascular disease, allergies, diabetes and liver disease) or are taking prescription drugs:

• Chamomile – Based on animal and human studies, the usual warning for chamomile is to avoid taking it with sedatives (including alcohol) because it may increase drowsiness. It should be avoided when taking an anticoagulant medication because it may interact with blood clotting. Those who take cholesterol lowering drugs should avoid chamomile because it causes statins to be broken down in the liver, rendering them less effective. People allergic to plants such as ragweed, chrysanthemums, marigolds, or daisies are more likely to experience allergic reactions to chamomile.
• Licorice root – It is suggested that licorice root should be avoided or consumed with caution if one is taking ACE inhibitors, diuretics, digoxin, aspirin, corticosteroids, insulin, or laxatives. In large amounts and with long-term use, licorice root can cause high blood pressure and low potassium levels, which could lead to heart and muscle problems. Some side effects are thought to be due to a chemical called glycyrrhizic acid. Licorice that has had this chemical removed (called DGL for deglycyrrhizinated licorice) may not have the same degree of side effects.
• Lemongrass: Lemongrass leaves are commonly used as “lemon” flavoring in herbal teas. Avoidance relates mostly to pregnancy (which WWURA members need not be concerned).
• Pomegranate: Some people (e.g., those with plant allergies) may be allergic to thinning medicine or drugs that work similarly in the body to warfarin. Federal agencies have taken action against companies selling pomegranate juice and supplements for deceptive advertising and making drug-like claims about the products.
• Ginger – Based on animal studies and human case studies, the common warning for ginger is to avoid it when taking anticoagulants. Taking both ginger and anticoagulant drugs may cause too much bleeding; however, scientific evidence is limited.
• Cranberry: Drinking cranberry juice appears to be safe, although large amounts can cause stomach upset and may over time increase the risk of kidney stones. Large doses of cranberry may alter levels of warfarin.
• Peppermint – One of the most commonly reported side effects of peppermint is that it causes heartburn. Peppermint can relax the lower esophageal sphincter (this keeps food in the stomach from going back up into the esophagus). People with gastroesophageal reflux disease (GERD), despite medications to prevent, are often advised to avoid peppermint.
• Hawthorn: Has been used for people with heart failure but long term studies have not confirmed effectiveness. Side effects of hawthorn can include dizziness, nausea, and digestive symptoms.
• Asian Ginseng: Short-term use of Asian ginseng in recommended amounts appears to be safe for most people. Safety of long-term use is not known. Some common side effects are headaches, sleep problems, and digestive problems. Ginseng might affect blood sugar and blood pressure. As with several other plants, it might interact with anti- coagulant drugs.
• Lavender: There is little scientific evidence of lavender’s effectiveness for most health uses. Extracts may cause stomach upset, joint pain, or headache.
• Kava: Comes from the Polynesian word "awa," which means bitter. It has been banned from the market in Europe and Canada due to heavy users developing severe liver disease. In March 2002, FDA warned health care providers and the public about the risk of liver damage associated with kava. Combining kava with alcohol increases such risk. Long-term use of high doses of kava has been associated with dry, scaly skin or yellowing of the skin. Heavy consumption of kava has been associated with heart problems and eye irritation.
• Passionflower: Is generally considered to be safe but may cause drowsiness.
• Valerian: Studies suggest that valerian is generally safe for use by most healthy adults for short periods of time. Little information is available about its long-term safety or its safety in children younger than age 3, pregnant women, or nursing mothers. Valerian may slow how quickly certain drugs are broken down by the liver, causing them to stay longer in the body. This includes anticonvulsants, benzodiazepines, insomnia prescribed drugs, and alcohol. The same liver enzymes that break down antihistamines and statins also break down valerian. Few side effects have been reported but some reports of headache, dizziness, itching, and digestive disturbances have occurred. Some studies show valerian is effective in inducing sleep after several days (12 to 24 days) of use but whether it is effective for treating insomnia has not been proven.

Note: Green, black, and oolong teas all come from the same plant, Camellia sinensis, but are prepared using different methods. To produce green tea, fresh leaves from the plant are lightly steamed.

Suggested resources: https://nccih.nih.gov/health/herbsataglance.htm http://www.just- health.net/Sleepy-Time-Tea.html

• http://umm.edu/health/medical/altmed/herb/valerian
• http://www.mayoclinic.org/diseases-conditions/insomnia/expert-answers/valerian/faq-20057875
• https://www.yogiproducts.com/ingredients/
• https://nutritionnutsandbolts.com/2012/11/07/herbal-tea-drug-interaction/