A study published within the Journal of the American Heart Association describes that excessive consumption of coffee can increase the danger of cardiovascular disease-related mortality in individuals with severe hypertension.

Study: Coffee and Green Tea Consumption and Cardiovascular Disease Mortality Amongst People With and Without Hypertension. Image Credit: Bohdan Malitskiy / Shutterstock

Background

Consumption of coffee is thought to scale back the danger of hypertension and related mortality in the overall population. Nonetheless, it might probably cause a transient increase in blood pressure amongst individuals with hypertension.

Evidence shows that the helpful effect of coffee consumption depends upon the blood pressure levels of people. In severe hypertension patients, coffee may cause an acute increase in blood pressure, increasing the danger of heart problems.

Alternatively, the consumption of green tea is thought to scale back blood pressure in patients with hypertension. Furthermore, green tea reduces the danger of all-cause mortality and cardiovascular disease-related mortality in the overall population.

In the present study, scientists have investigated the association between coffee or green tea consumption and the danger of cardiovascular disease-related mortality in Japanese men and girls with various degrees of hypertension.  

Study design

A complete of 18,609 individuals, including 6,574 men and 12,035 women, from 24 communities across Japan were enrolled within the study. The participants were asked to finish questionnaires to gather demographic characteristics, medical history, lifestyle, and food plan information.

The baseline blood pressure of participants was measured by trained personnel. Based on the blood pressure levels, the participants were categorized into five groups, including optimal and normal blood pressure, high‐normal blood pressure, grade 1 hypertension, grade 2 hypertension, and grade 3 hypertension.

Vital observations

The study explored the connection between coffee consumption rate and baseline characteristics of the participants belonging to every blood pressure category. A better rate of coffee consumption was observed amongst younger participants, current smokers, current drinkers, and fewer vegetable eaters. As well as, the participants with higher total levels of cholesterol and lower systolic blood pressure were also prone to be more frequent coffee drinkers.

The study also explored the connection between green tea consumption rate and baseline characteristics of the participants in each blood pressure category. A better rate of green tea consumption was observed amongst older participants, frequent fruit eaters, and employed participants.

An association between higher green tea consumption rate and lower total cholesterol level was observed amongst participants with grade 2-3 hypertension.

Coffee consumption and risk of heart problems mortality

A complete of 842 cardiovascular disease-related deaths occurred through the 18.9 years of the follow-up period.

The consumption of two or more cups of coffee a day was found to extend the danger of cardiovascular disease-related mortality amongst participants with grade 2-3 hypertension. In contrast, no such association was observed amongst participants with optimal and normal blood pressure, high-normal blood pressure, or grade 1 hypertension.

Green tea consumption and risk of heart problems mortality

The consumption of green tea was not found to extend the danger of cardiovascular disease-related mortality amongst participants with grade 1 to three hypertension.

Amongst participants with high-normal blood pressure or optimal/normal blood pressure, consuming 5-6 cups or 1-2 cups of green tea a day, respectively, barely reduced the danger of cardiovascular disease-related mortality. 

Green tea. Image Credit: Den Edryshov / Shuuterstock

Study significance

The study reveals that a high level of coffee consumption may cause 2-fold induction in the danger of cardiovascular disease-related mortality amongst individuals with severe hypertension but not amongst individuals without hypertension or grade 1 hypertension.

The study couldn’t find any negative impact of green tea consumption on the danger of cardiovascular disease-related mortality amongst individuals with mild or severe hypertension.

Some components of caffeinated coffee, including chlorogenic acid, magnesium, and trigonelline, are known to have health advantages, including reduced blood levels of cholesterol, inflammation, and improvement of endothelial functions. These positive effects nullify the negative cardiovascular effects of caffeine in the overall population.

Considering current study findings, the scientists suggest that the upper susceptibility of people with severe hypertension to opposed effects of caffeine might actually offset its health advantages and increase the danger of fatality.   

Caffeinated green tea, alternatively, comprises a high level of polyphenols, including epigallocatechin-gallate. Polyphenols have several health advantages, including anti-inflammatory, antioxidant, lipid-lowering, and blood pressure-lowering properties. The positive health effects of green tea catechins are sufficient to nullify the negative cardiovascular effects of caffeine.