Japan is beginning to see a shortage in matcha, the trendy green tea that has been promoted for its health benefits by social media influencers.
The tea, made from the finely ground powder of green tea leaves specially grown in shade, has been loved by Japan in particular since the 12th century when Buddhist monks introduced the nation to it.
Over the past decade, production has nearly tripled, with Japan producing 4,176 tonnes of matcha in 2023.
Consumption of the antioxidant-rich green tea 'reached a record high last year', according to Fumi Ueki, the chief of one of Japan's largest tea companies.
And soaring demand, largely driven by online trends, has prompted warning of further shortages this year.
Major influencers like Sophie Habboo and Kourtney Kardashian have espoused the benefits of matcha.
Matcha tea is made by combining fine matcha powder and hot water with a special matcha whisk, which is used to form a creamy foam that sits on the tea.
Proponents say the tea can boost the brain's health, due to its high concentration of polyphenols, chlorophyll, caffeine and L-theanine.
Japan is beginning to see a shortage in matcha, the trendy green tea that has been promoted for its health benefits by social media influencers
Soaring demand, largely driven by online trends, has prompted warning of further shortages this year
Matcha has gained a cult following online
The demand largely comes from outside Japan - while matcha and leaf green-tea consumption has fallen inside the country, global sales are expected to nearly double from £2.2bn in 2023 to £3.9bn by 2028.
In the past year alone, sales of matcha products have doubled in the UK. The arrival of the US cafe Blank Street to Britain's high streets in 2020 is thought to have led to a surge in the popularity here, with its range of matcha teas combined with other flavours such as blueberry and white chocolate.
The spike in demand has become such a problem that last year two of Japan's biggest tea companies, Ippodo and Marukyu Koyamaen, announced unprecedented purchase limits on matcha products.
But mounting evidence suggests too much can trigger iron deficiency. Left untreated, this can raise the risk of severe infections as well as life-threatening heart failure.
Iron, found in red meat and a variety of vegetables, is crucial for the production of red blood cells, which transport oxygen to the organs. It is also vital for a healthy immune system.
Experts now say that drinking just one matcha tea a day could cause problems.
Research suggests teenage girls, pregnant and post-menopausal women are at the highest risk of a matcha-related iron deficiency.
'People need to be aware of the potential risks of this drink,' says Dr Jeannine Baumgartner, an expert in nutrition and researcher at King's College London, who has studied matcha. 'There is a real danger of a deficiency, particularly for younger women who have higher iron needs.
Social media influencer Sophie Habboo (pictured) has espoused the drink's benefits
Blank Street in particular has capitalised on the matcha trend
It has long been known that green tea can, in some cases, trigger an iron deficiency.
This is because it contains high levels of tannins – a compound which gives tea its bitter flavour.
Research shows that tannins attach to iron molecules in the digestive system and prevent them from being absorbed.
A major review of over 150 studies in 2010 published by the Journal of Chinese Medicine found that consumption of more than three cups of regular green tea a day reduced iron absorption. However, it is believed that matcha has an even greater effect, as one cup has nearly seven times as many tannins as a similarly sized green tea.
As well as the tannins, caffeine has also been shown to reduce iron absorption and, per gram, matcha can contain up to four times as much caffeine as coffee.
Experts say this means that even one matcha a day could have health impacts.
'Matcha is much more problematic than green tea, as it is more concentrated so affects iron absorption even more,' says
Prof Baumgartner. 'Even one cup, if it is poorly timed, either during or up to two hours after a meal, will affect your iron levels.'
Kourtney Kardashian (pictured) has long been a proponent of matcha
She was seen making the tea on Keeping Up With The Kardashians
Iron deficiency is already a problem. Three per cent of men and 8 per cent of women in the UK have the iron deficiency condition anaemia, and it is on the rise. Symptoms include a yellowing of the skin, dizziness and depression.
Last year there was a tenfold rise in the number of people hospitalised with iron deficiency, with nearly 200,000 being admitted.
But there are steps that matcha drinkers can take to protect themselves against this complication.
'If you add milk or lemon juice, it can neutralise the tannins, which can help with iron absorption,' says Sarah Carolides, a London based nutritionist. 'It's also best to avoid using oat milk in your matcha latte as oats contain phytates, an acid which can also interfere with iron absorption.'
Timing is key for those considering a cup of green tea.
Prof Baumgartner recommends against drinking matcha within three hours before or after a meal. A 1983 study revealed a cup of green tea while eating a hamburger meal reduced iron consumption by 68 per cent.
As drinking habits change experts are calling for the guidelines to doctors looking out for iron deficiency to be updated.
'Doctors and GPs are not aware of the link between drinks and iron absorption and that really needs to change,' says Prof Baumgartner.
