New Delhi : Black tea may be gaining popularity among people for health reasons, but a new study in laboratory animals has shown that consumption of black tea may be harmful during pregnancy and lactation.  

The study has found that black tea extracts alter parameters of blood and liver in pregnant and lactating experimental albino rats. Bioactive components of black tea brew and their impact on human health is very important, especially during pregnancy and lactation.  

It says excessive drinking of black tea throughout pregnancy and lactation period decreases hemoglobin concentration and total count of red blood cells (RBCs) in rats. The study done by researchers from the Kolkata has been published recently in journal Proceedings of the Zoological Society.

The parameters were measured right from day one. Initially there was no significant change but after 20 days liver parameters started changing. Hepatocytes increased in size, there was loss of structural integrity, increased sinusoidal space, breakage of central vein etc. The effects were clear on blood as the RBCs became flattened and increased in numbers. The RBCs also lost their bi-concave architecture and no grooves or white patches were found in the membrane of RBCs.

ÂWe have studied the prenatal and postnatal stages which show that black tea extract makes changes in blood and liver parameters, lead researcher Dr Subir Chandra Dasgupta said while speaking to India Science Wire. He said tea was considered beneficial for human health but it may be harmful for pregnant women if consumed in excess. 

Bioactive components of black tea brew and their impact on human health is very important, especially during pregnancy and lactation. Little physiological changes during this period may alter mother and neonatal health. Thearubigins and theaflavin are major polyphenolic compounds found in black tea accounting for about 60-70% of its dry weight. Rest of black tea contains alkaloids, flavonoids, carbohydrates, amino acids. 

The study has been done by Department of Zoology, Maulana Azad College, Kolkata and Laboratory of Toxicology and Experimental Pharmacodynamics at University of Calcutta. The research team included Dr. Antony Gomes, Dr. Subir Chandra Dasgupta and Avijit Dey.