Just 2 Brazil Nuts a Day They Say.....

Just 2 Brazil Nuts a Day They Say.....

Why is selenium important?

Selenium is an essential mineral that is critical to human health. It is required in small amounts and is involved in many important processes in the body, including:

Thyroid hormone metabolism: Selenium is an important component of the enzymes that regulate thyroid hormone metabolism, which helps to maintain a healthy metabolism and overall energy levels.

Antioxidant defence: Selenium acts as an antioxidant, helping to neutralise harmful free radicals in the body and protect cells from oxidative damage.

Immune function: Selenium plays a role in maintaining a healthy immune system, helping to improve the body's ability to fight off infections and disease.

Reproductive health: Selenium is important for sperm motility and plays a role in male and female fertility and reproductive health.

Heart health: Adequate selenium intake may help to reduce the risk of heart disease by improving blood lipid levels and reducing inflammation in the body.

Reported food sources of selenium

Brazil nuts: These are considered one of the best food sources of selenium, with almost all sources saying “Just one or two nuts provide the daily recommended intake of selenium”. Read on see why this is total crap. For something that isn't crap - our orange hero bar delivers 114% of the RDI of selenium in one bar.

Seafood: Oysters, clams, mussels, crab, and shrimp are all good sources of selenium.

Meats: Beef, liver, and chicken are also good sources of selenium.

Whole grains: Whole wheat, barley, and brown rice are good sources of selenium.

Eggs: Especially the yolks, are a good source of selenium.

So just 2 Brazil nuts a day meets the selenium RDI?

Well, that’s what we are told. And why we performed this experiment. We wanted to be sure. We know that the selenium content in brazil nuts can be quite variable and depend on several factors, including the soil in which they are grown and the climate conditions during growth. Brazil nuts come from trees that grow in the Amazonian region of South America, and the soil in this region can have high or low levels of selenium. Additionally, the weather conditions during the growing season can impact the amount of selenium absorbed by the trees and the nuts they produce. For example, excessive rain or drought can reduce the amount of selenium available to the trees, while warm and dry conditions can increase selenium uptake.

Another factor that affects the selenium content of brazil nuts is the maturity of the nuts. Nuts harvested earlier in the season may have lower selenium levels, while those harvested later in the season may have higher levels. Furthermore, the processing and storage of the nuts can also impact their selenium content. For example, exposure to light, heat, or air can cause the nuts to lose some of their selenium content.

What triggered us to perform this experiment

We always test the nutrient concentrations of our products, before the production run in the testing phase for new recipes (and on the production run for every batch!) - this is so that we know we are making nutrient dense food - not much point otherwise!

In the first trial of our hero bar choc + orange, we were expecting to achieve 100% of the RDI of selenium in 1 bar - based on reported average selenium concentrations in Brazil nuts. But, instead, the results were bad, really really bad. The selenium content was undetectable. Naturally, I questioned the labs and asked them what had gone wrong, but no, they were confident that everything was in order with the results. I was miffed. But then I was inspired to learn more.

What we did

We wanted to know whether the issue we found with the Selenium content in Brazil nuts was just a one off or more wide spread. We hypothesised that it was more widespread. So we purchased 4 packets of brazil nuts from the supermarket and received 1 sample of brazil nuts from our manufacturing team. We sent a 50g sample of each of the brazil nuts to Australian Laboratory Services (ALS; NATA accredited laboratories) to measure the selenium content of the brazil nuts.

What we found

Based on the results we received from ALS (green bars ‘What The Labs Said’), the selenium content claims on 3 of the 5 packets of Brazil Nuts did not match and the remaining 2 did not report a selenium value in their nutrient information panel. Of the 3 that reported a selenium concentration (pink bars ‘What They Said’), all of the selenium concentrations we obtained were lower than the values reported. See Figure 1 below.

Figure 1. Figure 2. Reported vs measured selenium concentration in Brazil Nuts

Based on the product nutrient information panels (pink bars ‘What They Said’), to achieve the recommended daily intake (RDI) of selenium (60ug/day), you would need to eat 3-7g of brazil nuts a day (Figure 2). Based on the results we received from ALS (green bars ‘What The Labs Said’), to achieve the RDI of selenium (60ug/day), you would need to eat 20-64g of brazil nuts a day (Figure 2).

Figure 2. Reported vs measured weight of Brazil Nuts required to meet adult RDI of selenium

Figure 3 shows the same data as above, but presented as the number of Brazil nuts needed / day. Based on the average weight of a Brazil nut at 3g. Based on the product nutrient information panels (pink bars ‘What They Said’), to achieve the RDI of selenium (60ug/day), you would need to eat 1-2 brazil nuts a day. Based on the results we received from ALS (green bars ‘What The Labs Said’), to achieve the RDI of selenium, you would need to eat 7-21 brazil nuts a day.

Figure 2. Reported vs measured number of Brazil Nuts required to meet adult RDI of selenium

Why this matters

  1. Selenium is essential for optimum health. It is a potent antioxidant and has a role in fertility, muscle function, thyroid health, heart health and immunity.
  2. Selenium deficiency is a global concern and occurs in many countries, especially in developing regions where the soil is low in selenium. The effects of selenium deficiency can range from mild symptoms such as fatigue and muscle weakness to more serious consequences, such as an increased risk of infections, cardiovascular disease, and certain types of cancer.
  3. Thinking you only need to eat 2 brazil nuts to achieve your RDI, but finding you actually need to eat 21 is a remarkable difference and something people need to know. Because if brazil nuts are your only source of selenium and you only eat 2 a day, then you will become selenium deficient.
  4. One of the packets even made the claim on the back of the pack “Two Brazil nuts a day provides all the selenium you need”. NOT TRUE - for this brand you needed to eat 21!
  5. In high doses, selenium can be toxic. The reported safe upper limit for selenium is 400ug/day. Eating 21 brazil nuts (~63g), where the selenium content of the brazil nuts is as reported (1917ug/100g) would see someone consuming over 1200ug of selenium - 3 times the safe upper limit! Whereas the reality, for some of the brazil nuts we tested at least, is that 21 brazil nuts would see you only just reach the RDI of selenium. Accuracy in nutrition information panels is therefore critical to keep people nourished and safe.
  6. Nutrient information panels should accurately reflect the nutrient content of the food inside, not just an estimate from a generic database or a value generated from some other batch of product.
  7. People rely on nutrient information panels to guide their healthy eating choices. They need to be accurate to allow people to do so.
  8. Frankly, it's just dishonest and we think should be unacceptable practice for the food industry
  9. What we really want to do is change the conversation about the nutrient content of food. Did you know that the standard approach to addressing a nutrient deficiency (when producers bother to measure) in a food product is to add a synthetic vitamin and/or mineral supplement powder to the food to reach the target nutrient profile. If our food is so deficient in nutrients, let’s stop putting a bandaid fix over it. Lets instead address the nutrient deficiencies at their source, in the soil, and produce food that is nutritious. We say no to vitamin and mineral supplement powders. We say yes to honesty and transparency in food. We can’t fix a problem we can’t see. And right now most people in the industry are hiding the problem.

So what now?

  1. For you, help get the conversation started. Ask your food suppliers if they’ve tested the nutrient content of their food. They will almost certainly say no. Tell them our story and why you think this is so important. 
  2. Tell people about Eat for You and our testing regimen - the more we talk about what we are doing here, the more we can challenge the status quo and encourage more people to produce safe, honest, nutritious food.
  3. For us, we keep testing, we keep finding suppliers who can deliver nutrient dense food, we keep telling the truth, that’s the promise we’ve made to you and we are sticking to it.

How has Eat for You overcome the Brazil nut Selenium situation?

When we started Eat for You, we believed we were too small and couldn’t control the source of Brazil nuts. So at the very least we committed to telling the truth about the nutrient content of our foods and committed to continuing to do so. But, this didn’t feel like enough, and heck the small do hold the power if they use it right?! So we have worked with our manufacturing team and now have a supplier that we work with in Brazil to ensure we are supplied with Organic Brazil nuts for our products that actually contain Selenium! Our current batch of Hero Bars Chocolate + Orange contains 114% of the adult RDI of selenium in just 1 bar.

We will continue to test the Selenium content of our products (as well other relevant minerals and vitamins and macronutrients) and report these for our food. Sometimes a run of packaging extends across multiple batches. That’s why you’ll find a QR code on our packaging. This will take you to our nutrient panels page, where you can find the data for your specific batch (batch number is printed on the inside flap of all bars).


Selenium in Brazil nuts: An overview of agronomical aspects, recent trends in analytical chemistry, and health outcomes. Alcântara DB, Dionísio AP, Artur AG, Silveira BKS, Lopes AF, Guedes JAC, Luz LR, Nascimento RF, Lopes GS, Hermsdorff HHM, Zocolo GJ. Food Chem. 2022 Mar 15;372:131207. PMID: 34634585 Review.

Selenium content of Brazil nuts from two geographic locations in Brazil. J C Chang 1, W H Gutenmann, C M Reid, D J Lisk. Chemosphere. 1995 Feb;30(4):801-2. PMID: 7889353

Brazil nuts: Nutritional composition, health benefits and safety aspects. Cardoso BR, Duarte GBS, Reis BZ, Cozzolino SMF. Food Res Int. 2017 Oct;100(Pt 2):9-18. PMID: 28888463

Nutrient Reference Values for Australia and New Zealand - Selenium  https://www.eatforhealth.gov.au/nutrient-reference-values/nutrients/selenium

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