Black Or Green Tea For A Healthy Heart?
Tea drinkers have less infarction and stroke. We tell you why and which tea to choose.
Tea is an excellent source of compounds called flavonoids, antioxidants and natural anti-inflammatories interesting for heart health: they lower blood pressure, fluidify the blood and keep the arteries supple. But how do you choose your tea if you want to minimize the risk of infarction and stroke?
Tea drinkers have heart and vessels in healthy form
Several observational studies have found that tea consumers have better cardiovascular health than those who do not. They also have a reduced mortality, less infarction and stroke. These studies do not describe a cause-and-effect relationship, but suggest that protection from 3 cups of tea per day is removed. The risk of cardiovascular disease and mortality would then be reduced by 15 to 25%.
Tea against hypertension
It is believed that tea prevents cardiovascular disorders especially by lowering arterial pressure. For example, a study was conducted by doctors at the Georges-Pompidou European Hospital with volunteers aged between 18 and 95 years. They underwent a check-up between January 2001 and December 2008 and were followed for 3.5 years on average. During follow-up, 95 deaths from cardiovascular causes and 632 deaths from other causes were observed.
Results: tea consumers have a better cardiovascular risk profile than non-consumers, and smoking rates decrease with tea consumption (34% of non-drinkers versus 29% of large tea consumers). Physical activity increases with the number of cups of tea consumed daily. The consumption of tea is accompanied by a decrease of 4-5 mm Hg in systolic arterial pressure and 3 mmHg in diastolic arterial pressure in the large consumers of tea compared to non-consumers, after adjusting for age. Men tend to drink coffee more frequently than women, while women tend to drink more tea than men. The association between consumption patterns and mortality has shown an inverse association between tea consumption and cardiovascular mortality, but is not significant. On the other hand, tea consumers had a 24% reduction in noncardiovascular mortality, a benefit especially for former smokers.
Tea improves endothelial function
Tea leaves contain compounds called flavonoids, in particular flavanols (catechin and epicatechin, epigallocatechin, epicatechin gallate and epigallocatechin gallate or EGCG) and their oligomers called procyanidins.
The total amount of polyphenols varies little from one type of tea to another, but their profile is different depending on whether the tea is black or green. Thus, catechins account for 80-90% of green tea flavonoids, whereas in black tea, they constitute only 20-30% (50-60% of theaflavins). Flavonoids improve endothelial function and flux-mediated vasodilation (FMD), which explains their benefits on arterial pressure and the flexibility of the arteries.
Black or green tea?
Black tea (fermented) and green tea (unfermented) have many health benefits, including cardiovascular, but studies do not always distinguish between different forms of tea. When they do, the cardiovascular benefit usually goes to green tea.
For example, in a meta-analysis of 18 studies (13 for black tea, 5 for green tea), published in 2011, the researchers did not find that Big black tea drinkers had less coronary risk than those Who do not drink or little. On the other hand, for the large consumers of green tea, cardiovascular risk was reduced by 28% compared to non-consumers or small consumers. Every time you increase your green tea intake of one cup per day, you see this risk falling by 10%, according to this study, which nonetheless underlines the limited amount of scientific data on green tea.
We advise to choose teas of quality, in preference to teas first prizes, because they contain less aluminum. You can then drink several cups. People who have a risk of kidney stone (oxalate) often worry that tea can bring oxalic acid. This is especially the case with black tea (4 to 6 mg/g of soluble oxalate), whereas green tea contains only a small amount (0.20 to 1.2 mg/g). But, even with 5 to 6 cups of black tea per day, the amount of oxalate provided by tea remains low compared to that of food. As a precaution, we will opt for green tea (by adding it lemon juice, rich in citrate thus protective).
Danchin N. Coffee or tea consumption: no impact on cardiovascular mortality: the IPC cohort. Présenté au European congress of cardiology, Barcelona August 31st, 2014.
P. Elliott Miller et al. Association of tea intake with coronary artery calcification and cardiovascular events : results from the multi-ethnic study of artherosclerosis (MESA). Présentation à l’American Heart Association à Phoenix. Mars 2016.