Yerba Mate and Selenium – Is It a Good Source of This Mineral?

Yerba mate and selenium is the last missing piece of our series on minerals in the leaf of the Paraguayan holly – we’ve previously covered potassium, calcium, magnesium, zinc, sodium, phosphorus, iodine, iron, copper and manganese in a similar way. The principle stays the same: we check what’s actually known about the selenium content in the dried leaves and the infusion, what this element does for the body, and whether yerba even matters here in a daily diet.

Yerba mate and selenium – what the available data says

Selenium is a trace element whose content in plants depends almost entirely on the soil they grew in. It doesn’t appear in composition tables as consistently as potassium or magnesium – many analyses of Paraguayan holly leaves don’t isolate selenium as a separate item at all, and those that do give trace values, measured in micrograms per 100 g of dried leaves, not milligrams. We don’t have our own lab certificate with an exact selenium value for Yerbador’s dried leaves, so we won’t give a figure we’re not sure of – that’s a rule we stick to in every article of this series.

The reference intake value for selenium for an adult, as adopted in EU food labelling regulations, is 55 µg per day. The soils of South America where yerba grows are generally not rich in selenium – unlike some regions of the Amazon, where Brazil nut trees happen to grow. Even with the most optimistic reading from published tables, the yerba infusion alone doesn’t come close to a meaningful part of the daily requirement for this element.

Dried leaves vs. infusion – why it’s not the same number

Just like with manganese and copper in yerba mate – you drink the infusion made with hot water through a bombilla, you don’t eat the leaf itself. The wet leaves stay in the matero and after a few cebadas end up in the bin, so what actually ends up in your cup is only a fraction of what’s in the dry leaf. Selenium in plants occurs mainly bound to amino acids, and its solubility in hot water depends on the specific compounds it’s found in.

There are no reliable, repeatable studies that specifically isolate selenium in the yerba infusion, unlike potassium or magnesium, where the data is much better documented. It’s safest to assume that if there’s little of it in the dry leaf, even less ends up in the cup. Yerba mate is not a significant source of selenium, and it’s only fair to state that plainly instead of stretching the topic to fit the article’s title.

What the body needs selenium for

Selenium has its place on the list of officially approved health claims in EU food law, and it’s quite a long one. Among other things, it contributes to the normal function of the immune system, to normal thyroid function, to the protection of cells from oxidative stress, and to the maintenance of normal hair and nails. It also plays a role in normal spermatogenesis.

That’s a useful, fairly broad set of functions, but no single drink can replace them, especially when the data on selenium content in yerba is so uncertain and probably low. If you suspect a deficiency, especially with thyroid issues, the right path is talking to a doctor and getting a blood test, not counting rounds of matero.

Brazil nuts or yerba – what will actually give you selenium

We offer Brazil nuts, which are the richest, widely available source of selenium in the diet – and not by one order of magnitude, but by several. The label on our 250g pack shows 1917 µg of selenium per 100 g. A single nut usually weighs 4–5 g, which means one nut provides roughly 77–96 µg of selenium – already above the reference intake value of 55 µg per day. Two nuts a day is the upper limit of reason for most adults, since the European Food Safety Authority (EFSA) lowered the tolerable upper intake level of selenium for adults from 300 to 255 µg per day in 2023.

This is a completely different order of magnitude than what an infusion of yerba alone can provide. A single Brazil nut can realistically cover the daily selenium requirement in a way that drinking matero never will – and this isn’t about a lack of effort, but about the nature of the plant and the soil it comes from. Yerba remains what we reach for most often it for – flavour, ritual and a reasonable dose of caffeine, not a mineral supplement.

Who should pay special attention to selenium in their diet

For most people with a varied diet, selenium takes care of itself – it’s enough to occasionally reach for fish, eggs or Brazil nuts. A slightly higher risk of deficiency applies to people on unvaried plant-based diets, residents of regions with selenium-poor soils, and people with thyroid conditions, where this element plays a documented role in thyroid hormone metabolism.

There’s also another side to the coin, and with selenium it’s particularly important: it’s an element where overdosing is easy, because the difference between the needed dose and the harmful dose is small. Symptoms of chronic selenium excess (selenosis) include brittle hair and nails, skin changes, nausea and a characteristic garlicky breath odour. That’s why treating a Brazil nut like an ordinary snack you can eat by the handful is a mistake – here it really is about precision, not quantity.

How much yerba per day for this to matter

Since selenium from yerba is at best a trace amount not worth counting, the amount of infusion should be chosen primarily with caffeine in mind, not minerals. For a healthy adult, 2–3 servings a day, spread throughout the day and not drunk right before bed, is a range most people tolerate well. If selenium is specifically what you’re after, one or maybe two Brazil nuts a day will work far more effectively than any number of rounds of matero.

Where our dried leaves come from

The mineral composition of yerba also depends on where the leaf comes from and how it was dried. Our Yerbador dried leaves come with an analysis certificate from the Institute of Natural Fibres and Medicinal Plants (IWNIRZ, chromatography and authenticity confirmation), compliance with the standard confirmed by J.S. Hamilton, and testing for heavy metals, pesticides and PAHs performed by GBA Polska. On top of that, there are ECOCERT and Organic Brasil certifications and HACCP throughout the production chain. When it comes to a topic where the selenium figures themselves are uncertain, what matters more is that the dried leaves come from a trusted source, free from contamination risks that could throw off any mineral balance in the body.

Our products to try

If you want real support for your dietary selenium levels, reach for the Brazil nuts from our range – one or two a day is more than enough. If you also want to support your immunity more broadly, check out our Immuno dried yerba mate leaves with added green barley and sunflower seeds – a set designed for the whole immune system, not a single element.

Check the product: Brazil Nuts 250 g

Check out the product: Yerba Mate Immuno

Yerba mate and selenium – frequently asked questions

Is yerba mate a good source of selenium?
No. Available leaf analyses rarely isolate selenium at all, and when they do, the values are trace amounts at best. Brazil nuts are, by comparison, an incomparably better and well-documented source.

How much selenium is in a yerba infusion?
There isn’t one reliable figure – published studies rarely separate out selenium for the infusion as opposed to the dried leaf. We’d rather say that plainly than present an uncertain number as fact.

Do Brazil nuts have more selenium than yerba?
Definitely, and by several orders of magnitude. A single Brazil nut delivers more selenium than any realistic amount of yerba infusion could provide in a whole day.

Who should be careful with selenium?
Everyone should watch their dose, because with selenium the gap between a beneficial amount and a harmful one is small. Extra caution is advised for people taking selenium supplements and those who eat Brazil nuts by the handful instead of one at a time.

Is it worth drinking more yerba to get more selenium?
No, that’s a completely inefficient approach. One Brazil nut a day covers it better than any number of extra matero rounds, and the extra caffeine from drinking more yerba isn’t worth it.