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The popularity of matcha continues to boom. But recent videos on social media have suggested it could be bad for you if you have low iron.

One Sydney woman recently told media she had “no idea” her daily matcha latte could affect her health until she started experiencing headaches, and noticed her hair and nails were brittle and she was bruising easily. Blood tests found she was severely low in iron.

Similar videos on TikTok show women in hospital getting iron transfusions – and blaming their matcha habit.

So, let’s unpack this. How healthy is matcha? And can it really cause low iron?

What is matcha?

Matcha is a fine powder made from dried and ground-up green tea (Camellia sinensis) leaves. It has recently gained popularity as a drink and a flavour variety in many different foods.

Matcha contains many beneficial compounds (for example, dietary fibre and polyphenols) as well as being a source of caffeine.

Read more: Matcha is having a moment. What are the health benefits of this green tea drink?

Including matcha, or green tea, as part of a balanced diet may provide health benefits such as supporting healthy brain function and blood pressure.

However despite its health benefits, research has shown that drinking a lot of green tea is linked to lower levels of iron in the blood.

We need iron – but can’t make it

Iron is an essential micronutrient that helps transport oxygen around the body, as well as supporting many other important biological processes.

Our bodies can’t make iron, so we need to get it from our diet to support these functions. But even if we eat a lot of iron-rich foods, other things in our diet – such as coffee, red wine, calcium-rich foods and yes, matcha – can interfere with absorbing the iron.

So people with low iron levels need to be careful.

In particular, women who menstruate have an increased risk of low iron because of iron lost through bleeding.

You may have an iron deficiency if your iron falls below certain levels – typically for adults, less than 30 micrograms of iron per litre of blood. There are different cut offs for children.

Iron deficiency anaemia is a condition where very low levels of iron affect the functioning of red blood cells. It is diagnosed based on levels of haemoglobin in the blood (these cutoffs vary by age, sex and pregnancy status).

What does matcha do to iron levels?

There are two main components in green tea that stop us absorbing iron. These are polyphenols and phytic acid (also known as phytate).

Both polyphenols and phytic acid have their own health benefits, for example, protecting against chronic diseases such as type 2 diabetes. But they also bind to iron and prevent it from being absorbed into the body.

So, if you have a lot of food or drink that contains these components – especially in combination with iron-rich foods – they can reduce iron absorption.

However, it’s not only matcha that can interfere. Phytic acids are also found in other teas and many plant foods, such as nuts, cereals and legumes. Tea, coffee, berries, and other fruits and vegetables are also high in polyphenols.

How much matcha will affect your iron levels?

This varies between people.

One study showed people who drink three or more cups of green tea a day had lower blood iron levels than those who drink less than one a day. But they didn’t experience iron deficiency any more often.

However other research has linked moderate green tea consumption (two cups a day) to iron deficiency anaemia.

Whether or not your matcha latte will contribute to an iron deficiency depends on many other factors, including your existing iron levels.

So, what about matcha-flavoured foods?

In these – for example, matcha ice cream – the actual amount of green tea powder is very low. This means it’s unlikely to significantly affect iron absorption.

But it’s not just about quantity – when you drink your matcha also matters.

To reduce the impact on iron absorption, it’s recommended you have green tea separately from meals – at least one hour between eating and drinking tea.

What else to keep an eye on

Multiple other factors in your diet can influence iron absorption. What you eat may either exacerbate or counteract the effects of your matcha latte on iron absorption.

Overall, balance is key to ensure you are getting the full spectrum of nutrients the body requires.

To support iron levels, you can incorporate iron-rich foods (such as beans, lentils, meat, fish and fortified cereals) into a healthy diet.

Eating vitamin C-rich foods (such as capsicum, broccoli, kiwifruit and other fruit and vegetables) along with foods that contain iron can help to enhance iron absorption.

If you are concerned about your iron levels, you should speak to a health-care professional – especially if experiencing symptoms of iron deficiency (such as tiredness, weakness or dizziness).

A blood test can diagnose low iron levels. If you have an iron deficiency, your GP or dietitian will help you manage symptoms and work out what is right for you.

This article is republished from The Conversation, a nonprofit, independent news organization bringing you facts and trustworthy analysis to help you make sense of our complex world. It was written by: Margaret Murray, Swinburne University of Technology

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Margaret Murray does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.