Updated: May 11, 2019
Next to water, tea is the most widely consumed beverage in the world and has been touted for many health benefits.
Tea provides a small amount of magnesium, calcium, potassium, phosphorus, and other trace elements considered necessary for health. Tea also contains catechins, which are a type of antioxidant. White and green teas have the highest concentration of these while oolong and black teas have less due to the oxidative preparation.
Tea also contains caffeine which may vary from 30 to 90 mg/cup depending on the type of tea and method of brewing. Other medicinal ingredients are theobromine and theophylline found in smaller quantities. Tea may have many potential health benefits especially for cardiovascular health and in regard to cancer, diabetes, weight, infections, tooth decay, periodontal disease and may provide some protection from depression and may be protective against Alzheimer’s
A recent study found that tea may also be contaminated with heave metals. For the study, common off-the-shelf varieties of black, green, white, and oolong teas sold in tea bags were used for analysis. Toxic element testing was performed on 30 different teas by analyzing (i) tea leaves, (ii) tea steeped for 3-4 minutes, and (iii) tea steeped for 15–17 minutes.
- All brewed teas contained lead with 73% of teas brewed for 3 minutes and 83% brewed for 15 minutes having lead levels considered unsafe for consumption during pregnancy and lactation. Aluminum levels were above the recommended guidelines in 20% of brewed teas. No mercury was found at detectable levels in any brewed tea samples.
- All teas had significant levels of aluminum and 6 out of 30 teas brewed for 15 minutes had high levels. Drinking more than 4 cups of tea a day may contribute significantly to a toxic load.
- Brewed tea appears to contain numerous toxic elements such as arsenic and cadmium. However, none of the levels of these toxins was above present day acceptable standards.
- Steeping tea for longer periods of time increases the levels of these contaminants by 10 to 50% over steeping for 3 minutes. Therefore steeping for longer than 3 minutes should be avoided.
- The source of water used for brewing may contain some contaminants and add to the toxic load.
- Organic teas did not always fair better.
For your benefit, and to help lower the impact of these potential contaminants this, this chart shows you which teas and from which regions, had the lowest levels of heavy metals. In addition, to lower the impact of these potential contaminants, use a short brewing time and limit total consumption.
The Benefits and Risks of Consuming Brewed Tea: Beware of Toxic Element Contamination
Journal of Toxicology
Volume 2013 (2013), Article ID 370460, 8 pages