Studies show matcha can "inactivate" Covid – so is it time to ditch the traditional cuppa? Photo / Eric Helgas, The New York Times
Matcha: there’s just no stopping this Kermit-coloured drink. Slurped by A-list celebs from Gwyneth Paltrow to Brad Pitt, it generates 188 million search results on Google, and Instagram glows green with #matcha lattes, teas, milkshakes, sodas, hot chocolates, smoothies, ice creams and more.
Walk into any British café, health food shop or supermarket and you’re likely to find matcha: global sales are now worth more than £2.2 billion (NZ$4.6 billion). In fact, a survey by The Grocer this year found matcha was among the alternative teabags nudging black tea out of our cupboards; traditional brews now account for less than half our teabag spending.
What’s driving the unstoppable craze for this luminous drink? Its photogenic colour is part of it, of course. But the raft of supposed health benefits, from stronger bones and improved memory to reduced risk of heart attack and defence against cancer, underpin its popularity.
This month, a Japanese study published in the prestigious Nature journal found that sipping a matcha latte or tea could effectively “inactivate” the Covid virus. Scientists from the Kyoto Prefectural University of Medicine in Japan discovered that molecules in the drink bind to the spike protein sticking out from the surface of the virus and stop it from infecting cells.
But does the scientific evidence really match the hype? Are all the different health claims about matcha true?
Matcha is a type of green tea traditionally consumed in Japan. It’s made from the same plant (Camellia sinensis) as other types of green and black teas, but because it’s cultivated differently it has special nutritional qualities and flavour. (Black tea is allowed to oxidise after harvest and green tea isn’t, which accounts for the difference in colour.)
Unlike standard green tea, the plants used for matcha are grown in the shade, and as a result contain higher concentrations of key active compounds. Once the leaves are harvested, they’re steamed to preserve their colour and nutrients, then ground into a fine powder. This is sprinkled into hot or cold liquids such as water, milk or even lemonade, or added to foods.
Nutritionist Kerry Torrens says matcha not only contains more beneficial compounds than standard green tea because of the way it’s grown, but also because whole leaves are used rather than an infusion to make drinks. The key compounds in matcha include l-theanine (an amino acid with stress-relieving properties), vitamin C (an antioxidant, which protects cells from damage) and caffeine (a stimulant linked to improved brain function and alertness).
“Also, like standard green tea, matcha is rich in plant defence chemicals called polyphenols,” Torrens explains. “The notable difference is that matcha is richer in a type known as epigallocatechin gallate or EGCG.”
Professor Gunter Kuhnle, from the Department of Food and Nutritional Sciences at Reading University, agrees there’s plenty of evidence that flavanols – a family of polyphenols found in green tea – deliver significant health benefits.
“In general, green tea – whether it’s matcha or not – is a source of a lot of flavanols, which have a beneficial effect on our health, including reducing the risk of cardiovascular disease,” Prof Kuhnle says. Scientists don’t yet understand how these compounds protect our hearts. “But it’s very clear there’s a reduction in risk – as much as a 20 per cent reduced risk of cardiovascular disease in one study.”
There’s also evidence that flavanols can help manage cholesterol levels. “The idea is that flavanols bind with cholesterol in the gut, a bit like fibre, and remove it from the body,” Prof Kuhnle says. And in case you’re wondering, yes matcha and green tea are higher in flavanols than your standard black tea.
Many of the compounds in matcha, including polyphenols, chlorophyll, caffeine and l-theanine, can potentially boost brain function. “Caffeine improves alertness and focus, L-theanine relaxes, while polyphenols protect the brain and they’re good for memory too,” Torrens says.
Caffeine also contains antioxidants, which protect cells from damage. Combined with the polyphenols in matcha, it may help prevent or slow the progression of conditions such as Alzheimer’s and Parkinson’s disease.
Prof Kuhnle urges caution, though. His research suggests flavanol-rich drinks and supplements only improve the cognitive function of people who don’t consume enough in their diet.
Torrens says L-theanine may support the nervous system and have a calming effect at times of stress.
“Matcha is both relaxing and heightens alertness and focus, so has special qualities in that respect,” she says. “Caffeine and L-theanine both play a part here.” She adds that if you have trouble sleeping, it’s worth avoiding any caffeinated drinks, including matcha, after midday.
There is some evidence that green tea, including matcha, may support weight management. “When combined with caffeine it appears to help reduce visceral fat,” Torrens says. “These benefits are improved when combined with exercise – for example, 30 minutes of brisk walking each day.”
Matcha may support bone health, Torrens says, by protecting against bone loss. “It does this by influencing osteoclasts, the cells that break down bone,” she says.
Some studies suggest that matcha may have a role to play in preventing the development and spread of cancer. However, there’s no solid evidence to support this, according to Cancer Research UK. “There is some evidence from early studies to suggest that having green tea might reduce the risk of some cancers,” the charity says. “But at the moment the evidence is not strong enough to know this for sure.”
Research into green tea and matcha is promising, but there’s a long way to go before science proves there are benefits. “Many of the studies are conducted using animal models or cells in a laboratory, so more clinical trials and studies are needed to fully understand matcha’s contribution to human health,” Torrens says.
No one knows how much matcha is optimum, as there are so many variables, she says. The quality of the matcha, how it’s grown, processed and prepared, as well as an individual’s genetic make-up, all affect how much is needed to have an effect.
“But one or two cups per day consumed regularly is often cited as beneficial, as part of a varied, balanced diet,” Torrens says. She recommends opting for high-quality matcha that’s bright green with an extremely fine and silky texture.
Sadly, Torrens doubts there’s much to be gained health-wise from tucking into a matcha brownie or cookie. “They’re unlikely to have any therapeutic benefit at all because they are typically a cheaper powdered green tea, rather than premium matcha,” she says.
Prof Kuhnle adds it’s unclear how the active compounds in matcha are affected when combined with other ingredients. His research has shown that enzymes in bananas destroy flavanols, for example, so banana and matcha smoothies probably won’t be as healthy as green tea. And given matcha powder is stirred into a variety of liquids, there’s no way of knowing if the drink is doing you much good at all.
But matcha isn’t a magic jade bullet. Healthy compounds like flavanols are abundant in fruit and veges, so eating a variety of fresh produce could deliver the same health benefits as a pricey green drink.
“But if you do drink matcha as a way to consume more flavanols, to top up if you like, there’s definitely a benefit,” Prof Kuhnle says.
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