Is green tea really as healthy as they say?
Drinking a few cups of green tea every day fits well into a healthy lifestyle and is probably safe, but do not take green tea extracts as a supplement: they can damage your liver.
Green tea contains compounds that show clear biological effects in the lab and in animals, most notably EGCG (epigallocatechin gallate), an antioxidant. It reduces the oxidation of LDL cholesterol and other early signs of atherosclerosis in lab, animal and small clinical studies. That mechanism is plausible, but direct protection of cells and tissue in humans has not yet been well established.
The evidence is strongest for cardiovascular disease. Population studies in Southeast Asian countries find an association between regularly drinking green tea and a lower risk of cardiovascular disease. People who drink five or six cups a day also tend to score better on blood pressure and blood sugar. But these are associations observed in large groups; clinical studies in individual people are scarce and short in duration, and it may be that healthy people simply drink more tea.
For cancer prevention the picture is considerably less clear. Cell and animal studies are promising, but population studies in humans still contradict one another. There is currently insufficient basis to say that green tea prevents cancer. The same applies to protection of the nervous system: interesting signals from cell and animal research, but evidence in humans is still largely absent.
An important safety point: green tea as a drink is probably safe, but concentrated green tea extracts in supplement form are a different matter. Research points to a real risk of liver toxicity and possible DNA damage at high doses. Green tea extract supplements are therefore not without consequence and are explicitly flagged as a concern in the literature. Drinking ordinary tea does not carry that risk.
Weight management is a popular claim, but the supporting evidence is thin. There are tentative signals, nothing more. And the safety of tea supplements for fat loss has also not been adequately studied.
All sources are reviews; no randomised trials or meta-analyses were directly provided as a source. The association with cardiovascular disease rests largely on population research without random assignment.
How many cups of green tea do you need per day?
Two to three cups of tea per day shows the most favourable association with cardiovascular health across several large analyses; drinking more adds little benefit, but do let your tea cool down before drinking.
Is coffee healthy or unhealthy?
For healthy adults, moderate coffee consumption (3 to 5 cups per day) is more likely to be healthy than unhealthy; if you are pregnant or prone to anxiety, moderation or consultation with your doctor is advisable.
How healthy is olive oil and what is it good for?
Olive oil, and extra-virgin olive oil in particular, is well supported as protective for the heart and blood vessels, especially when used in place of butter and as part of a varied, plant-based diet.
Is coffee good or bad for your heart?
For most healthy adults, three to four filtered cups per day are associated with a beneficial effect on the heart and blood vessels. Pregnant women are an important exception: for them, the maximum is one to two cups per day.
How bad is eating a lot of salt for me?
Eating a lot of salt is clearly harmful to your blood pressure and your heart, and the risk grows with the amount consumed. Eating more vegetables and fruit helps to temper the effect, but does not replace reducing salt intake.
Does coffee lower the risk of premature death?
Coffee (2 to 4 cups per day, preferably in the morning and without much sugar) is associated with a lower risk of premature death, but this is an association, not a proven cause. Pregnant women are better off avoiding coffee.