Effects Of Caffeine and Green Tea on Pregnant Women
Pregnancy is a critical period for an expecting woman. Pregnant women should be careful to limit the amount of green tea they consume during pregnancy. Green tea is rich in antioxidants, and has a many health benefits, but researchers have found that an active constituent of green tea, the Epigallocatechins (EGCG), may affect the way the body uses folate. Folate is important for pregnant women as it prevents neural tube birth defects in babies.
The problem of drinking green tea during pregnancy is that the EGCG molecules are structurally similar to a compound called methotrexate. Methotrexate is able to kill cancer cells by chemically bonding with an enzyme in the body called enzyme dihydrofolate reductase (DHFR). Healthy people have this enzyme also – it is part of what is called the folate pathway, which is like a pathway, the body takes to transform nutrients like folate into something that can be used to support its normal functions.
But this chemical similarity also means that the EGCG in green tea also binds with the enzyme DHFR, and when it does this, it inactivates this enzyme. When this enzyme is inactivated, the ability of the body to use folate is affected.
The good news on caffeine consumed during pregnancy, from coffee and tea, is that a moderate amount is fine. Two studies, one by Danish scientists who interviewed more than 88,000 pregnant women, and the other by the Yale University School of Medicine, had similar findings on beneficial affect of caffeine during pregnancy.
The concerns over large intake of caffeine were that it can lead to low birth weight or miscarriage. The Yale team found that drinking about 600mg of caffeine a day, which is about 6 cups of coffee, would reduce birth weight to levels that were clinically significant. The rate at which birth weight was reduced was established at being 28 grams per 100 mg, or 1 cup, of coffee per day. But they stressed that this would not be significant for moderate caffeine consumption.
The Danish study found that drinking 8 cups or more of coffee per day increases the chances of miscarriage, or stillbirth, by 60% compared to women who did not drink caffeine. They also found that moderate coffee or tea drinking did not pose significant risks. For those drinking half a cup to 3 cups of coffee a day, the risk of fetal death was 3% higher compared to non-caffeine drinkers. For those drinking 4 to 7 cups of coffee a day, the risk increases to 33%. One cup of coffee equals about 2 cups of tea when comparing caffeine levels.
