The benefits of coffee
Coffee has many known benefits and a lot of scientific evidence to back them up. Here is a brief list of the main ones.
- Boosts alertness
- Reduces the risk of heart attacks and strokes in healthy individuals
- Reduces the risk of developing chronic illnesses such as type 2 diabetes and some cancers
- May help control appetite
- May help lower the risk of depression
To be fair, there are also several recognized harmful effects. Too much coffee may raise blood pressure, and lead to anxiety, heart palpitations, and difficulty sleeping. These drawbacks may be particularly problematic for people who are already suffering from severe hypertension.
“Our study aimed to determine whether the known protective effect of coffee also applies to individuals with different degrees of hypertension, and also examined the effects of green tea in the same population. To the best of our knowledge, this is the first study to find an association between drinking 2 or more cups of coffee daily and cardiovascular disease mortality among people with severe hypertension,” said the study’s senior author Hiroyasu Iso.
Researchers studied people with various degrees of hypertension
This new study included over 6,570 men and over 12,000 women, ages 40 to 79 years, who were followed up with over 19 years. The participants provided data through health examinations and self-administered questionnaires assessing lifestyle, diet and medical history. The researchers classified participants’ blood pressure into five categories:
- Optimal and normal (under 130/85 mm Hg)
- High normal (130-139/85-89 mm Hg)
- Grade 1 hypertension (140-159/90-99 mm Hg)
- Grade 2 hypertension (160-179/100-109 mm Hg)
- Grade 3 hypertension (over 180/110 mm Hg)
Hypertension and coffee don’t go well together
The results of the study show that drinking 2 or more cups of coffee per day is associated with double the risk of cardiovascular-disease death in people with severe hypertension compared to those who did not drink any coffee. People suffering from grade 2 and 3 hypertension (160/100 mm Hg or higher) were considered to have severe hypertension.
“These findings may support the assertion that people with severe high blood pressure should avoid drinking excessive coffee. Because people with severe hypertension are more susceptible to the effects of caffeine, caffeine’s harmful effects may outweigh its protective effects and may increase the risk of death,” said Iso.
One cup of coffee or tea daily is safe
The study also found that 1 cup of coffee and daily green tea consumption didn’t increase the risk of death related to cardiovascular disease, even in people with severe hypertension. This is an interesting finding because both coffee and tea contain caffeine. A 250 ml cup of green or black tea has 30-50 mg of caffeine, and the same cup of coffee has between 80-100 mg.
It’s important to keep in mind that the research has some limitations. For example, coffee and tea consumption were self-reported. Also, the observational nature of the study means that it can’t draw a direct cause-and-effect connection, only an association.
We will need further research to learn more about the effects of coffee and green tea consumption on people with high blood pressure. But if you want to be on the safe side, this study would have you limiting coffee to 1 cup per day or less if you’re struggling with severe hypertension. If tea is your beverage of choice, you have a green light to drink it daily.