China has seen a surprising trend in green teas promoted as containing above-average levels of the necessary trace element selenium. These “selenium-rich” green teas are being touted as great tasting and healthy while also commanding higher prices than comparable non-enriched teas. While these teas (and the marketing thereof) may offer true benefits, several barriers to promoting selenium-rich green teas need to be addressed.
Selenium (Se) is an element in the periodic table and occurs naturally in some metal ores. It is toxic in large quantities, but trace amounts are necessary for cellular function, and selenium is included in many multivitamins and dietary supplements. Selenium is particularly necessary for the function of the thyroid gland and its related hormones.
Studies have also indicated that selenium can reduce the impact of low-level mercury toxicity in the body. Further studies are exploring selenium-based antioxidants and their roles in inflammatory and chronic diseases.
Marketing and promotion of selenium enriched teas is in its infancy. A web search for selenium teas reveals few options, most of which are green teas from China, and retailing between $11 and $15 per 100 grams.
Several areas in China have begun to promote selenium-enriched green teas. In general, these areas share some common traits:
- Areas are often associated with poverty alleviation efforts
- Selenium-enriched areas are often new growth or otherwise developing tea fields
A few of the larger and better-known selenium-enriched tea areas include:
Enshi, Hubei Province, has seen an increase in tea growing, including selenium-enriched green teas, for over a decade. Due to expansion in areas like Enshi, Hubei Province rose from the 5th largest producing province in 2009 to the 3rd largest in 2019. During that period, Enshi’s selenium enriched green tea output value went from $1.6 million in 2009 to $183 million in 2017. Enshi currently has over 22,000 hectares of tea fields. It constitutes one of the largest and best known selenium-enriched green tea production areas in China.
Ziyang, Shaanxi Province, has an estimated 16,000 hectares of selenium-enriched green tea fields with an annual output of 7,538 metric tons. The development of selenium-enriched green and other teas has contributed to lifting thousands of smallholder tea farmers above the poverty line.
Newer areas, like Jiangjin Chongqing Municipality, Datian, Fujian Province, and Fengcheng, Jiangxi are scheduled to see further development. Datian, Fujian alone has been estimated to contain 836 square kilometers of selenium-rich land and estimated to represent over one-third of China’s total selenium-rich arable land.
REGULATIONS AND STANDARDS
Along with the expanding cultivation of selenium-enriched land comes the need for standards and quality assurance for these green teas. Issues have already arisen in Enshi, where journalistic investigations revealed a lack of standards and enforcement. Green teas and other local crops were touted as selenium-enriched, but measures of actual selenium content in these local agricultural products were non-existent or insufficient. Additionally, some farmers were rumored to have been using selenium fertilizers to maintain higher levels of selenium in their crops. While it is possible to apply organic-compliant selenium fertilizers, there appeared to be little guidance and regulation regarding the application to selenium-enriched tea fields. Investigations further suggested the possibility that some selenium fertilizers being applied contained compounds harmful to the human body. In addition, the practice of using selenium fertilizers might suggest that the natural selenium content in the soil in Enshi may have been depleted or exhausted. Some of the selenium soil tests in Enshi date back to the 1980s or 90s. Which raises the question: if the land is no longer “selenium-rich,” what constitutes a sustainable, selenium-enriched tea operation?
The market for selenium-enriched green teas continues to grow in China, both in terms of production and sales volume. As they do, green tea consumers in China and beyond can watch for several developments:
- Standards and testing for qualified selenium-enriched green teas will improve, with more complete guidance on what qualifies as a selenium-enriched tea from selenium-rich land
- For quality selenium-rich green tea, the presence of beneficial selenium will be an additional feather to the tea’s health-cap
- Qualified selenium-enriched teas from developing and sustainable tea fields makes for an attractive feature. When combined with sustainable tea-growing practices, the appeal of selenium-enriched green teas could help increase the value of teas during initial years of lower quantity harvests at newly established fields. As yields increase and selenium soil concentrations (potentially) decrease, the value added to these green teas can be shifted to offer other efficiencies or distinguishing characteristics associated with the tea’s origin