Drink Coffee or Tea to Lower Your Blood Pressure
Can it be that coffee and tea are good for your heart? It goes against almost everything we have heard about coffee and tea. It’s true that there have been a few little hints that coffee and tea are good for us, although many other studies have concluded that excessive amounts of coffee or tea should be avoided. A recent article published in EmaxHealth even discussed some of the problems associated with caffeine addiction and withdrawal. Conflicting reports have made it difficult for the average person to know what to believe regarding coffee and tea and how much is too much.
In this article I am going to present the results of a recent retrospective study that examined the association between coffee/tea and high blood pressure. The results may surprise you.
What is a retrospective study?
There are two main types of studies. One is called a prospective study. In a prospective study researchers form a hypothesis and then design a study that is intended to show if the hypothesis is true or false. The other type of study is called a retrospective study. In a respective study, researcher use data that has already been collected and look back in time (hence retro) to see if they can find any associations or correlations between the data.
Conditions of the study
The researchers in this study examined data from almost 200,000 patients, male and female, ages 16 to 95 years of age, between 2001 and 2011. Patient records contained information on blood pressure, pulse pressure and heart rate, and coffee/tea consumption. Researchers divided the patients into 3 groups based on coffee/tea intake: (1) no coffee/tea, (2) 1-4 cups per day, and (3) > 4 cups per day. Next the researchers calculated the average blood pressure (systolic & diastolic), pulse pressure and heart rate for each group.
The results were presented by Dr Bruno Pannier at the European Society of Hypertension (2013) in June, 2013. Dr Pannier found that coffee/tea drinkers had significantly* lower values on all measured parameters compared to those who did not drink coffee or tea. He also found that, in general, tea drinkers benefited more than coffee drinkers and those that consumed more than 4 cups per day benefited more than those who drank 1-4 cups per day.
*In scientific studies the word ‘significantly’ has a slightly different meaning from the one used in everyday life. In scientific studies, ‘significantly’ means that it is very unlikely that the results were due to random chance. In this particular case, it means that the researchers believe that 9,999 times out of 10,000, the observed changes in blood pressure parameters were due to the coffee/tea consumption.
One of the shortcomings of a retrospective study is that they don’t let us determine what caused the observed change. It might be tempting to say that the change was due to caffeine since we know caffeine is present in both drinks. However, it could be, and probably is, due to the anti-oxidant properties of the flavonoids that are present in both beverages. This is also supported by the fact that tea, especially green tea, has more flavonoids than coffee, which would explain why tea drinkers had better parameter values than coffee drinkers.
What does it mean if it is the flavonoids?
Actually this would be a good thing. As I mentioned before, there are some down sides to drinking too much caffeine, with caffeine addiction being just one. On the other hand, there appears to be no down sides to flavonoids. If you like tea, then consider making it green tea or white tea. Both have more flavonoids than black tea or coffee. If you would prefer your flavonoids without caffeine, then I would suggest:
• grape juice,
• black cherry juice,
• cranberry juice or
• pomegranate juice.
All these juices have much higher levels of flavonoids than either coffee or tea (any type).