Yerba Mate and Iron – Does It Block Absorption? Who Should Be Careful

Yerba mate and iron is a question that usually comes up from two completely different groups. The first is women with low ferritin, whom a doctor or dietitian has suggested take a closer look at what they drink with meals. The second is people on a plant-based diet who heard somewhere that tannins in infusions “block” iron, and got worried. Both groups have good reason to be interested, but the answer doesn’t fit into one simple yes-or-no sentence. We break it down below, without scaremongering and without pretending the topic doesn’t exist.

Does yerba mate block iron absorption? The short answer

Yes, but not all iron, and not in every situation. The tannins found in dried yerba mate leaves bind with non-heme iron – the kind found in plants like legumes, grains and leafy vegetables – and hinder its absorption in the intestine if you drink the infusion during or right after a meal. Heme iron, from meat and fish, reacts to this much less. For a healthy person with a varied diet, drinking yerba mate in reasonable amounts and spaced apart from meals, this is a marginal issue. For people with iron deficiency, pregnant women, or those on a mostly plant-based diet – it’s not quite so simple, and that’s what the rest of this article is about.

Tannins in yerba mate – how it works

The dried leaves of the Paraguayan holly, from which yerba mate is made, contain a fair amount of polyphenols, including tannins and chlorogenic acid. These same compounds are partly responsible for the slightly tart, herbal-spicy flavour of the infusion and for its antioxidant effect. The problem is that tannins have a strong affinity for iron – in the digestive tract they bind with it into compounds the body cannot absorb. Instead of entering the bloodstream, that portion of iron simply passes through.

Exactly the same mechanism was described for black tea and coffee back in the 1970s – this isn’t a discovery specific to yerba mate. Classic studies on tannins in beverages show that drinks providing 20-50 mg of polyphenols per serving can reduce iron absorption from a meal by 50-70%, while those richer in tannins, above 100 mg per serving, can reduce it by as much as 60-90%. Yerba mate falls into the same category as black tea – it’s an infusion made from leaves, not a filtered extract, so tannins end up in the brew in significant amounts.

Heme iron and non-heme iron – why this distinction matters

The body absorbs iron from two sources in completely different ways. Heme iron comes from meat, fish and offal and is absorbed efficiently, largely regardless of what you drink with your meal – tannins have limited effect on it. Non-heme iron comes from plants: lentils, beans, quinoa, spinach, tofu, fortified breakfast cereals – and this is the type that’s sensitive to tannins from yerba mate.

In practice, this means that someone who eats red meat a few times a week and drinks their matero separately doesn’t have much reason to worry. Someone who gets most of their dietary iron from plants already has a solid reason to pay attention to when they reach for yerba.

What research on yerba mate and iron shows

This isn’t just theory. One study on the effect of polyphenols from Ilex paraguariensis – the Latin name for the Paraguayan holly from which yerba mate is made – on iron absorption showed that when iron in the form of ferrous sulfate was given together with yerba mate infusion, absorption dropped from about 8% in the control group to about 2% in the group that drank the infusion. That’s a drop in bioavailability of over 70%, and this with just one serving of the infusion given with a meal.

A second study examined something of the opposite, but equally instructive. It was conducted on fourteen patients with hereditary hemochromatosis – a disease in which the body absorbs too much iron. Participants were given a meal with iron, washed down with either water or yerba mate infusion, in random order, with a week’s break between trials. The rise in blood iron levels after the meal was noticeably lower when they drank yerba instead of water, and no adverse effects were recorded. For people with excess iron, that’s good news, but above all it confirms the mechanism this whole article is about – in humans, not just in a test tube.

Who should actually pay attention to this

Not everyone needs to worry about the gap between their matero and dinner. It’s worth thinking about if you fall into one of these groups:

• you’ve been diagnosed with iron-deficiency anemia or have low ferritin,
• you’re pregnant, when iron requirements rise noticeably above typical values,
• you follow a vegetarian or vegan diet, where almost all the iron in your meals is non-heme,
• you have heavy periods, through which you lose more iron than average,
• you donate blood regularly.

If you suspect you have a deficiency, the symptoms can be tricky to spot – constant tiredness despite a full night’s sleep, paleness, brittle nails, dizziness when standing up quickly. On their own, they don’t prove anything, since they can also point to many other causes. The only reliable way to check is a blood test – a complete blood count with ferritin, not guessing based on how you feel. If the result confirms a deficiency, a conversation with a doctor or dietitian will tell you more than any blog article ever could.

How to drink yerba mate without losing iron from your meal

A few simple habits are enough to put this issue to rest, instead of giving up your matero altogether:

• leave about an hour’s gap between yerba and a meal rich in plant-based iron – in both directions,
• don’t wash down an iron supplement with yerba, the same gap applies here just as it does with food,
• drink your matero between meals, for example mid-morning, rather than alongside a plate of lentils or beans,
• pair plant-based iron sources with vitamin C – peppers, parsley, citrus fruits, tomatoes – since it supports the absorption of non-heme iron and partly offsets the effect of tannins.

This last point also works the other way around. If you want to drink yerba close to a meal, a sour addition to a plant-based dish will soften the effect of tannins, even if it doesn’t eliminate it completely. The same rules apply to coffee and classic black tea, so if you already have the habit of not washing down dinner with coffee, carrying that over to yerba won’t require any change to your daily routine.

Purity of the dried leaves – that’s something we check for you

How much iron you absorb from a meal isn’t affected by the quality of the dried leaves – that’s a matter of physiology, not the leaf itself. But since you’re already minding the gaps and planning your diet with iron in mind, it’s good to know exactly what ends up in your matero. Our yerba mate grows in Brazil and is packed in Europe. Every batch is tested: GBA Polska checks for heavy metals, pesticides and PAHs, the Institute of Natural Fibres and Medicinal Plants confirms the authenticity of the leaves through chromatography, and J.S. Hamilton verifies compliance with the reference standard. On top of that, there’s HACCP, KIWA certification, Swiss OROTAL supervision, and a Quality Certificate from the National Medicines Institute. We publish the full list of reports on our research page.

Our products to try

Three suggestions that fit with what we covered above – from portion control to drinking yerba away from the table.

Yerba De Brasil – Doypack 0.5 kg

Classic, unflavoured dried leaves – a good starting point if you want full control over how much yerba you drink and when. Two spoons to begin with, more only once you know how you react. Check the current price.

Check out the product: Yerba De Brasil – Doypack 0.5 kg

Exclusive Ceramic Matero

A vessel with a fixed capacity makes it easier to keep an eye on portions – you pour the same amount every time, so it’s easier to plan when to drink yerba in relation to iron-rich meals. Check the current price.

Check out the product: Exclusive Ceramic Matero

Terremos Pro Max + Doypack free

A stainless steel flask with a spring filter and a straw – a handy way to take your yerba along for the whole day and drink it at your own pace, away from meals, instead of constantly topping up the same matero with hot water at the table. Check the current price.

Check out the product: Terremos Pro Max

Frequently asked questions about yerba mate and iron

Can yerba mate lead to anaemia?

On its own, in a person with a balanced diet and normal iron stores, probably not. The risk increases when it overlaps with an existing deficiency or an iron-poor diet, and yerba mate is drunk with every meal, day after day.

How long should you wait between yerba mate and an iron-rich meal?

Generally, a gap of about an hour in either direction is recommended. That’s enough to prevent tannins from meeting iron from the meal at the same stage of digestion.

Does yerba mate also affect iron from meat?

To a much lesser extent. Heme iron from meat and fish is absorbed largely independently of tannins, so for people who eat meat regularly this issue matters less.

Does yerba mate itself contain iron?

Yes, the dried leaves contain trace amounts of iron alongside other micronutrients, but it’s too little to count yerba mate as a source of this element in the diet. What matters more is how the infusion affects iron absorption from other foods, not how much it provides itself.

I’m taking an iron supplement – can I drink yerba mate with it?

It’s better not to combine them at the same time. Keep a similar gap as with a meal, and ask your doctor or pharmacist for recommendations specific to the preparation you’re taking.