Tuesday, June 24, 2014
Black tea belongs to the family of oolong, green and white teas. Black tea is more oxidized than the other three teas in the family. All the teas in this family are derived from the leaves of the shrub Camellia Sinensis. The flavour of black tea is stronger than the rest and its flavours last longer as well.
Scientists from Zhejiang University in the People’s Republic of China in a study suggested that regular consumption of black tea has a positive effect on LDL cholesterol levels as it reduces the LDL levels but has no effect on HDL cholesterol. The report studied meta-analysis of randomised controlled trials to support their findings. Scientists also reported that people with higher cardiovascular risk, like hypercholesterolemia benefitted more from the consumption of black tea than other people.
The journal of Clinical Nutrition noted that “It has been reported that 1 mg/dL reduction of LDL cholesterol concentration can reduce coronary artery disease risk by 1%, therefore a 4.64 mg/dL reduction of serum LDL cholesterol concentration [as reported in this meta-analysis] is of both statistical significance and clinical importance.”
Many studies have researched the benefits of the popular and widely consumed green tea, but there is an increasing body of research that has come to the surface that supports the benefits of black tea.
Green tea contains between 30 and 40% of water-extractable polyphenols, while black tea (green tea that has been oxidized by fermentation) contains between 3 and 10%. The four primary polyphenols found in fresh tealeaves are epigallocatechin gallate (EGCG), epigallocatechin, epicatechin gallate, and epicatechin.
Black tea, contains and ingredient called catechins which has been found to regulate LDL cholesterol levels supressing the absorption of cholesterol in the intestine in turn increasing the rate of conversion of cholesterol to bile acids, advised Chinese scientist
“Black tea polyphenols are also shown to suppress cholesterol biosynthesis and to promote the expression of LDL cholesterol receptor,” they wrote. “Apart from lowering LDL cholesterol, black tea can protect against cardiovascular disease via other pathways like through its antioxidant and antifibrinolytic property.”
Beverage vs extracts
In a research conducted by Dr Duo Li, the study examined 411 adults in a randomised trial. The study concluded that black tea consumption was associated with the substantial decrease in LDL levels of, on average, 4.64 mg/dl. However, the HDL levels remained largely unchanged.
Researchers found that, the black tea extract is more beneficial than the beverage. “However, we cannot assert that, black tea extract is better than black tea beverage in regulating LDL cholesterol concentration at this stage,” they wrote. “Only two of the nine trials adopted black tea extract as intervention trials and limited number of included studies in this subgroup could tender the statistical strength of the results.”
“Therefore, further research is needed to explore whether there is appreciable difference between black tea beverage and black tea extract in improving serum cholesterol profile and enhancing human health.”
In conclusion, Black tea has proven to be beneficial in helping lower LDL levels, but not increase HDL levels. However, there is no harm in drinking one –three cups of black tea. It would definitely help the increase of anti-oxidants in the body.