Green tea danger for pregnant mums

Pregnant women who drink green tea increase the risk of birth defects such as spina bifida, experts say.

The chemical extracted from the tea also inhibits the growth of cancer cells and may provide the starting point for a new family of anti-cancer drugs, scientists say.

Studies have already shown that people who drink green tea are less likely to suffer certain forms of cancer. The new study provides an explanation for the beverage’s anti-cancer effect. The effect was seen even at low concentrations equivalent to drinking two or three cups of green tea a day.

Drop in folic acid levels

Scientists found that polyphenol EGCG binds to the enzyme dihydrofolate reductase (DHFR) which is already an established target for chemotherapy drugs. DHFR is also implicated in birth defects.

The green tea compound stops DHFR promoting DNA synthesis in tumour cells. It appears to work in the same way as the cancer drug methotrexate, but in practice would probably have fewer side effects.

Professor Roger Thorneley, from the John Innes Centre in Norwich, who conducted the research, said: “This is a very exciting discovery. For the first time we have a clear scientific explanation of why EGCG inhibits the growth of cancer cells at concentrations which are found in the blood of people who drink two or three cups of green tea a day.

“We have identified the enzyme in tumour cells that EGCG targets and understand how it stops this enzyme from making DNA. This means we may be able to develop new anti-cancer drugs based on the structure of the EGCG molecule.”

Studies have also linked high levels of green tea consumption around the time of conception and during pregnancy with an increased incidents of spina bifida and anencephaly, a birth defect that results in the absence of part of the brain and skull.

Both are ‘neural tube’ disorders associated with folic acid deficiency. The scientists said EGCG in green tea would be expected to cause a significant drop in folic acid levels.

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