Tea and its heart health benefits
Tea is one of the most popular drinks in the world. Tea is not only a simple and inexpensive beverage but also have many health benefits, including weight control, cancer treatment and cardiovascular disease prevention.
In 2007, Michele Antonello and others published a study on the effect of green tea extract in arterial hypertension as well as the mechanism of green tea extract on cardiovascular protection.
Study of Curtin University of Technology in (Australia, 2007) had said that we should be encouraged to drink tea and tea might be used as a potential way for prevention of stroke. In addition, report of scientists at University of California and published in “Stroke” (2009) also concluded that by taking 3 or more cups of green tea, we can have 21% reduction of risk of ischemic stroke, comparing with who use only 1 cup per day.
A new study in 2012 of Dr. Ananya Mandal shows that drinking tea daily can lower your blood pressure. It is clear evidence that there were 10% reduction in hypertension and 7% to 10% reduction in risk of heart diseases.
So, how is tea good for high blood pressure and which is component of it help to lower blood pressure? Many studies investigated these compounds in tea can help prevention high blood pressure, including L-theanine.
L-theanine in tea
L-theanine is an amino acid that found naturally in tea leaves. L-theanine takes about 50% of total amino acid in tea. However, a cup of green tea just contains only 8mg of L-theanine. It is so surprised that black tea contains at least 3 times of L-theanine content in green tea. The antioxidant activity of L-theanine can affect on oxidation of LDL cholesterols. That will lead to heart health benefits including lowering high blood pressure and stroke protective effect.
In 2008, scientists at University of Bristol (England) compared the effects of caffeine and L-theanine that are found in tea on high blood pressure. Based on this study’s result, they concluded that L-theanine can reduce blood pressure while caffeine can increase blood pressure.
Moreover, taking a high dose of L-theanine may not lead to negative effect on health. In 2006, a study performed in rats, scientists had administered very high dose of L-theanine every day for 13 weeks. The rats didn’t show any negative effects on behavior, food intake, body weight, clinical chemistry, urine, blood, morbidity or mortality. However, you should ask your doctor for taking L-theanine because a long term effect of L-theanine have not been studied yet although the FDA had classified L-theanine supplements as “Generally Recognized As Safe”.
References
Livestrong.com; L-theanine & Hypertension. July, 2011.
