High blood pressure place a 15% role in all deaths in the United States. 28% of the Americans have high blood pressure but don’t know about it. Given these figures, we’re talking here about a pretty significant topic. Some say that lowering blood pressure is as easy as one, two, TEA! Is this true? Our team have looked into the results of influential scientific articles.
A study of 1994 published in the American Journal of Hypertension shows a significant reduction in blood pressure of rats after they’re fed with γ-Aminobutyric acid (GABA) rich tea. Moreover, the intake of tea also seem to prevent hypertension.
Green tea and high blood pressure
Green tea is known to be good against blood pressure due to it’s ECGC content, which is a polyphenol present in green tea. A study of 2007 from American Journal of Physiology shows that hypertensive rats enjoyed significantly lowered systolic blood pressure after ECGC therapy.
In the same year, a journal called “Obesity” published a paper in which men and women in Japan participated. This study concludes that ingestion of catechins can reduces body fat, cholesterol levels, and blood pressure without the need for change in lifestyle. It might also prevent obesity and lower the risk of heart disease. Catechins are a type of flavonoids present in tea. A study in 2008 from the journal Inflammopharmacology” supports this claim, but ads tea with lower caffeine levels are better. Caffeine in green tea might interfere with blood pressure medicine and could result in short-term high blood pressure.
However, not all studies show supporting results. For example, a study in 2007 in Arch Intern Med found that there’s no significant effect on blood pressure.
What about other tea types?
Though green tea has been covered the most by researchers, there’s no reason to believe that other tea types don’t offer similar benefits. After all, all leaf teas are made from the same Camellia Sinenses tea plant. The categorisation of tea is based on the processing methods applied.
One often cited article is one that was published in Preventive Medicine in 1992. This study was important because it included 9,856 men and 10,233 women with no history of heart disease or diabetes in Norway. The study shows that tea (any of leaf tea type) resulted in lower blood pressure among participants, though it showed a stronger effect on women. During that time, most people in Norway consumed black tea, as green tea wasn’t popular yet. What’s also interesting to note is that more participants died 12 years after the study who drank 1 cup (or less) a day. This result wasn’t statistically significant though, and may require even more participants to proof.
In 2013 a paper published in the Journal of Nutrition, focused specifically on black tea, shows that the inclusion of black tea in in a relatively low fat diet reduces cholesterol levels and thus may reduce the risk of heart diseases.
A study in 2012 of Arch Intern Med also demonstrated that black tea can also lower blood pressure.
Perhaps a research published in The Journal of Nutritional Biochemistry is the most interesting as it tests black, green and oolong tea at the same time. All 3 types show that it has the capability reduce fatty acids and cholesterol levels in rats. Green tea, however, seems to show a stronger effect, as green tea reduced fat storage in the liver of rats studied.
Herbal tea and high blood pressure
Instead of leaf tea, can herbal tea help against high blood pressure? In 1999, a study the Journal of Ethnopharmacology shows an 11.2% lowering of the systolic blood pressure and a 10.7% decrease of diastolic pressure after 12 days of Hibiscus tea consumption.
A study from the Journal of Nutrition in 2010 confirms this conclusion. The study shows that the antioxidant benefits can decrease blood pressure in adults who suffer from mild high blood pressure. However, this tea might cause high blood pressure if taken with diuretics.