Study Vague on Green Tea Improving Down’s Syndrome

Study Vague on Green Tea Improving Down's Syndrome

The Lancet Neurology published a randomized, double-blinded phase 2 trial (i.e.: not preliminary) about using green tea supplements to improve quality of life in patients with Down’s syndrome.

Although the results are reportedly positive, there are scant details available without a subscription which makes trying to parse things out or understand the context rather difficult. Still, enough is available that some observations can be made to hopefully add context to the reported findings.

Green Tea and Down’s Syndrome Study: Summary

  • The study had a test group of 43 young adults with Down’s syndrome and a control group of 41
  • The test group was given decaffeinated green tea supplement containing 45% of the phytochemical EGCG for 12 months
  • Both groups were given weekly sessions of online cognitive training, with tests at the three, six, and 12-month mark
  • Most categories showed no change, but the test group did “significantly” better in the ability to remember patterns, verbal recall, and adaptive behavior
  • The test group showed this improvement over time and the improvements lasted for about six months after the trial ended

What This Means

What these results might mean to anyone with Down’s syndrome is still being determined. It’s important to remember that this is a phase two clinical trial and that does affect how much action can be taken on it. Clinical trials are broken down into three main phases:

  • Phase 1: Test the drug on healthy people and establish proper dose ranges
  • Phase 2: Test the drug on patients in a experimental setting to assess for efficacy (how it performs under ideal conditions) and safety
  • Phase 3: Test the drug on patients in a clinic (real-use) setting to assess for effectiveness (how it performs in the real world), safety, and efficacy

A majority of treatments that show promise in phase two subsequently fail phase three for various possible reasons including but not limited to:

  • The treatment is too hard to follow properly
  • Environmental or lifestyle factors impair effectiveness
  • People tend to behave differently when under laboratory observation, which can affect findings
  • Phase three trials are much larger than phase two and results tend to average out. What may appear a significant effect in a smaller group could be revealed to be a minor or insignificant effect in a larger one

In other words, these results are interesting but until the ECGC treatment passes phase three it would be premature for someone to try and act on the study’s information outside of research. The study authors emphasize this by pointing out in the press release that the findings need further validation and that, even if they were correct, it would be more of a “quality of life” improvement than a “cure” for Down’s syndrome.

Bottom Line

  • It’s a promising phase two clinical trial, but nothing more can be said until further research is conducted


“Green tea seen boosting cognitive ability of people with Down syndrome,” Japan Times web site, June 7, 2016;