Doesn't mean anything.  Lots of people could substitute
"beer" for "green tea extract" in that statement,
but that wouldn't recommend drinking beer for health.

You think that, but you don't know that.

Pregnant women should not drink tea because
it interferes with folic acid metabolism,
which creates a risk of neural tube defects.

Ann Epidemiol. 2000 Oct 1;10(7):476-477.
Prenatal tea consumption and risks of anencephaly
and spina bifida.
Correa A, Stolley A, Liu Y.
National Center for Environmental Health, Centers
for Disease Control, Atlanta, GA, USA

PURPOSE: To evaluate the relationship between
prenatal tea consumption and risk of anencephaly
and spina bifida.

METHODS: Data from the population-based Atlanta
Birth Defects Case-Control Study were examined.
Cases were infants with anencephaly (n = 122) or
spina bifida (r = 154) and no other associated
anomalies, and identified between 1968 and 1980.
Controls were infants without birth defects
(n = 3029) identified from birth certificates of
the same birth cohort and frequency matched to
cases by race, period of birth, and hospital of
birth.

RESULTS: Maternal tea consumption during the
periconceptional period (3 months before through
the first trimester of pregnancy) was reported at
82, 83.6, and 92.9% among controls, anencephaly,
and spina bifida cases, respectively. With subjects
whose mothers consumed no tea as a reference,
odds ratios (OR) for tea consumption during the
periconceptional period (adjusted for gender, race,
period of birth, maternal age, education, alcohol
consumption, smoking, and periconceptional
multivitamins) were: anencephaly 0.9 (95% confidence
limits (CI) 0.5-1.5); spina bifida 2.3 (CI 1.2-4.4).
Odds ratios for spina bifida and number of cups of
tea consumed/day were: 1-2 cups 2.1 (CI 1.1-4.0);
3+ cups 2.8 (CI 1.4-5.6). Consumption of other
caffeinated beverages was not associated with risk
for anencephaly or spina bifida.

CONCLUSIONS: Further studies are warranted to
corroborate and elucidate the observed association
between tea consumption and spina bifida.