Nothing soothes us like our favourite cuppa, but can we have too much of a good thing? Maria Fitzpatrick finds out
Why is it that the things we love most are bad for us? That is what we’ve been led to believe about tea. Nearly 80 per cent of the population drinks it regularly, yet we keep being told to cut down our caffeine intake. We’ve heard the scare stories. Earlier this year fertility experts claimed four caffeine drinks a day could cut pregnancy success rates by a quarter. So what are the myths? Here, we sort the hearsay from the hard facts.
What do the scientists say?
Bridget Aisbitt, a scientist from the British Nutrition Foundation, says there is strong evidence that tea helps to keep the heart healthy. In studies across Europe, drinking three or more cups a day has been shown to reduce the risk of heart disease. “We’re not certain why they help, but flavonoids are thought to be one reason.”
What makes tea healthy?
“The plant from which tea is made is rich in polyphenolic flavonoids, which have powerful antioxidant properties,” says Lynne Garton, a nutritionist who advises the UK Tea Council. “Flavonoids exist in cocoa and red wine and are thought to benefit the heart as well as possibly having a role in preventing cancers by protecting cells from free radical damage. However, they aren’t always effective in low doses. For this reason, it’s great that we drink so much tea.”
Green tea v black tea
“Many people believe green tea is vastly superior to black tea, which isn’t true,” says Lynne. “Both types contain similar amounts of caffeine and flavonoids.” Caffeine levels among the major tea brands are very similar.
“Hydration is really important for brain performance,” says Bridget Aisbitt, “and tea really helps in this regard. It’s particularly important for older people to keep drinking their tea. There’s a common misconception that because tea contains caffeine, it dehydrates the body, and that we have to drink more water to compensate. In fact, tea is 99.5 per cent water. It can count in your recommended intake of six to eight glasses of fluid [1.2 litres] a day. Caffeine only has a diuretic effect if you consume more than 300mg [equivalent to six to seven cups] in one go.”
The caffeine factor
Between 38-400mg (up to eight cups of tea) is moderate. It can improve alertness, mood and concentration, says Lynne Garton.
But the negative effects of caffeine consumption cannot be ignored. Caffeine is thought to inhibit the absorption of iron and some vitamins. As well as being essential to the diet, iron is needed for red blood cell production and function. A US study last year showed that taking caffeine at the same time as paracetamol can put you at risk of liver damage. It has also been linked (in very high doses) to headaches, jitteriness, digestive disruption and insomnia.
However, as Bridget Aisbitt says, “everyone has different reactions to caffeine, and they should be aware of those sensitivities.”
Although tea doesn’t have anything like the amount of caffeine in coffee, she advises moderate drinking. “Pregnant women, however, do need to be aware of their intake, because pregnancy changes the rate of metabolisation of caffeine.” The Food Standards Agency says pregnant women can have six cups of tea a day without risk to their health.
The long-term effects of caffeine consumption are not clear, as many studies have concentrated on very large doses. However, if you drink more than eight cups a day, you should consider substituting a few cups of decaffeinated tea. Many people avoid decaffeinated tea, believing that its beneficial properties are lost in the decaffeination process. However, the effect on polyphenols (the antioxidants) is considered to be marginal.
Does how you drink it make a difference?
Four cups a day, with milk, provides 21 per cent of the adult calcium requirement. “Although it’s a small amount of milk, it adds up, so it’s a good source – and for B vitamins, too,” says Bridget.
“Many people believe that putting milk in tea prevents flavonoids from working,” says Lynne, “but studies have shown they were active with and without the presence of milk.” Jeremy Sturges, master blender at Twinings, says the type of tea can make a difference.
“The tea in teabags is often more finely cut, which releases extracts more quickly. And the brewing time does make a difference to the level of caffeine in the final drink. The largest proportion of caffeine is released in the first minute of brewing. The longer you brew anything, the more will be extracted.”
Source: The Telegraph, UK