Green tea catechins promote oxidative stress

Inexperienced tea is seen as wholesome and promotes an extended life, supposedly as a result of its excessive stage of antioxidants. Researchers at ETH Zurich have now solid doubt on earlier assumptions about how these components work.

Inexperienced tea has lengthy been recognized to have well being advantages. Specifically, it comprises catechins referred to as ECG and EGCG which are mentioned to extend life. These two substances belong to the group of polyphenols. They’re thought of antioxidants, which suggests they counteract or forestall oxidative stress within the physique attributable to aggressive free radicals of oxygen.

Till now, analysis has assumed that the catechins neutralize these free radicals and thus forestall injury to cells or DNA. One supply of oxygen free radicals is metabolism; for instance, when the mitochondria—the powerhouses of the cell—are working to supply vitality.

ETH researchers led by Michael Ristow, Professor of Vitality Metabolism on the Division of Well being Sciences and Expertise at ETH Zurich, along with colleagues from the College of Jena, have now taken a more in-depth have a look at how catechins act within the nematode worm C. elegans. They usually have come to a distinct, seemingly paradoxical conclusion: Reasonably than suppressing oxidative stress, the catechins in inexperienced tea put it on the market.

Non permanent enhance in oxidative stress

In a research simply revealed within the journal Getting old, Ristow’s crew exhibits that these polyphenols from inexperienced tea initially enhance oxidative stress within the quick time period, however that this has the next impact of accelerating the defensive capabilities of the cells and the organism. Because of this, the catechins in inexperienced tea led to longer life and better health in nematodes that have been fed them.

“Which means inexperienced tea polyphenols, or catechins, aren’t, in reality, antioxidants, however reasonably pro-oxidants that enhance the organism’s capacity to defend itself, just like a vaccination,” explains research chief Ristow.

Nonetheless, this enhance in defensive functionality manifests not by the immune system, however reasonably by activating genes that produce sure enzymes similar to superoxide dismutase (SOD) and catalase (CTL). It’s these enzymes that inactivate the free radicals within the nematode; they’re primarily endogenous antioxidants.

Sport and calorie discount have an identical impact

Ristow is not stunned to see this sort of mechanism at work. His analysis group confirmed again in 2009 that the rationale sport promotes well being is as a result of sporting actions enhance oxidative stress within the quick time period, thus bettering the physique’s defenses. Consuming fewer energy has the identical impact, as has been proven a number of occasions in animals. Mice fed a reduced-calorie weight-reduction plan dwell longer than these fed a traditional, high-calorie weight-reduction plan. “So it made sense to me that the catechins in inexperienced tea would work in an identical manner,” Ristow explains.

He goes on to say that the findings from this research translate nicely to people. The fundamental biochemical processes by which organisms neutralize oxygen free radicals are conserved in evolutionary historical past and are current in the whole lot from unicellular yeast to people.

Inexperienced tea sure, concentrates no

Ristow himself drinks inexperienced tea daily, a apply he recommends. However he advises in opposition to taking inexperienced tea extracts or concentrates. “At a sure focus, it turns into poisonous,” he says. Excessive-dose catechins inhibit mitochondria to such an extent that cell loss of life ensues, which might be notably harmful within the liver. Anybody consuming these polyphenols in extreme doses dangers damaging their organs.

Whereas probably the most catechins are to be present in Japanese types of inexperienced tea, different inexperienced teas additionally comprise adequate quantities of those polyphenols. Black tea, however, comprises a a lot decrease stage of catechins, since these are largely destroyed by the fermentation course of. “That is why inexperienced tea is preferable to black tea,” Ristow says.