Green to go: benefits of green tea

Green tea vs. green tea extracts: which are best?

By Benita Lee, for Montana Health Journal

Green tea is one of those rare herbal products growing in consumer popularity.

In fact, in today’s dietary supplement market is veering towards prevention, self-care, and holistic approaches to wellness backed by credible claims. And with green tea linked in research to benefits like preventing diabetes, cancer and other chronic diseases, along with no notable evidence of severe adverse risks even at fairly high dosages, the impetus for consuming green tea is strong.

As far as industry trends go, green tea supplements are gaining traction more quickly than traditional tea leaves, but the tea leaf industry still dominates in terms of market value. According to market analysis reports, the global market value for extracts of tea polyphenols, the active components of green tea concentrated in supplement capsules, was about $209.3 million in 2012 with a growth rate of 7.4%. North America accounted for 27% of this total market volume. The real answer to our question about which form of green tea is better lies in how each differs in its process of extracting green tea’s beneficial components.

Green tea extract can contain the following compounds: • Polyphenols: catechins, phenolic acids, tannins, and flavonols (kaempferol, quercetin, myricitin, and rutin) • Xanthines: caffeine and caffeine-related stimulants (theobromine and theophylline) • vitamin C and B vitamins • Amino acids: L-theanine • Microelements: aluminum, fluorides, manganese • Essential oils The main active ingredients in green tea include caffeine and caffeine-related stimulants, specific flavonols, which act as antioxidants, and the highly researched class of green tea catechins. Some of green tea’s elements also come with risks. For example, the Food and Drug Administration cites 400 mg as the safe threshold for daily caffeine consumption. Above 400 mg, health risks include gastrointestinal upset, muscle tremors and palpitations. Tea leaves also tend to accumulate aluminum from soil, and chronic high aluminum exposure (more than 20 mg per day for a 150-pound person) has been found to cause Alzheimer’s disease. Though that’s a fair warning, research suggests that one cup of brewed black tea has a little less than one milligram of aluminum and most of it is not absorbed by our bodies because it remains bound to L-theanine, another component found in tea.

Make it right

Making green tea by brewing tea leaves is not a consistent activity for obvious reasons. Water temperature, time of steeping, amount of tea leaves, and brand of tea leaves all affect the tea’s final flavor and quantities of compounds present in the tea itself. In one study, brewed tea contained 87 to 106 mg of polyphenols per gram of green tea dry matter, of which 52 to 84 mg were catechins. Green tea supplements are often made with concentrated polyphenol or catechin extracts.

Green tea leaves are pulverized and then subjected to organic solvents to isolate green tea polyphenols from the leaves. Labdoor’s Green Tea Rankings show that not all supplements are made equal. Many come unstandardized, in proprietary undetailed blends, or as simply as ground tea leaves that have been placed in a capsule. The inaccuracy of supplement labels themselves presents a serious disadvantage when choosing a supplement. In Labdoor’s analysis of 25 green tea supplements, measured caffeine content was anywhere from only 42.6 percent of the caffeine claimed on a label to 131.5 percent more than what the label stated, and almost all of the products with labeled primary catechin amounts measured less catechin content than claimed. Nevertheless, primary green tea catechin content ranged from 27.9 - 484.9 mg per serving, perhaps comparable to the quantity you could obtain from a day's worth of green tea. And at least one research study found that green tea polyphenols were more readily absorbed and resulted in higher antioxidant activity if they came in purified capsule form compared to a drink.