Warning for Green and Black Tea Drinks!
Green tea itself has many potential health benefits including promoting weight loss as well as beneficial effects on glucose tolerance (potentially beneficial for people with diabetes). Both green as well as black teas are rich in polyphenols which are antioxidants.
Despite the many potential health benefits of both green and black teas, a recent study suggests that there maybe one important adverse health-related effect related to tea consumption.
Folic acid is an important vitamin for several reasons. Deficiencies of folic acid have been linked to the followingconditions:
- cardiovascular disease
- growth retardation
- megaloblastic anemia
- neural tube defects (in children born from mother’s who have deficiency during pregnancy)
- increased levels of homocysteine
A recent study published in the journal, Biopharmaceutics & Drug disposition (Alemdaroglu et al, 2008), suggests that drinking either green or black tea may actually lower the bioavailability of folic acid.
At the 0.4 mg folic acid dose, green and black tea reduced the mean C(max) of serum folate by 39.2% and 38.6%
The present results suggest an in vivo interaction between tea and folic acid with even low concentrations of green and black tea extracts yielding decreased bioavailabilities of folic acid.
- Pregnant women may want to eliminate or at least restrict their consumption of both green/black tea. Lower folic acid bioavailability is a potential risk for neural tube defects.
- For those who do consume green/black teas, you will want to ensure that you don’t take your vitamins (containing folic acid) with tea.
- Alemdaroglu NC, Dietz U, Wolffram S, Spahn-Langguth H, Langguth P. Influence of green and black tea on folic acid pharmacokinetics in healthy volunteers: potential risk of diminished folic acid bioavailability. Biopharm Drug Dispos. 2008 Sep;29(6):335-48.