Brazil Nuts: Health Benefits + How To Enjoy The Rich Source of Selenium

Nuts are often a go-to snack or a topping for salads and other meals. Brazil nuts have become more popular because they contain a higher selenium concentration than other nuts. However, many advise that Brazil nuts be consumed in moderation to avoid unpleasant side effects.

So, what’s the deal with Brazil nuts? How healthy are they to consume? We spoke to registered dietitians to get more insight into the nutritional value of Brazil nuts and how to use them as a natural selenium supplement.

Brazil nuts aren’t nuts but large seeds originating from northern Brazil, specifically the Amazon region. These seeds come in clusters between eight to 24 inside a hard shell emulating a coconut. In the wild, Brazil nuts grow from the Brazilian nut tree Bertholletia Excelsa.

Brazil nuts taste similar to macadamia nuts, with a smooth and oily texture. They have a creamy, buttery taste that resembles other nuts. These large nuts can be found in grocery stores and online through retailers and cost $20 or more, depending on how many pounds each pack contains.

Here’s a look at the nutritional components of one ounce (or a handful, about 8 nuts) of Brazilian nuts, according to the USDA1. 

Amanda Li, R.D., a Toronto-based registered dietitian of Wellness Simplified, adds that Brazil nuts also contain micronutrients such as vitamin E, zinc, and manganese. In addition, Li states that Brazil nuts, like other nuts, are a great source of unsaturated fatty acids that reduce heart disease risk2, control heart rhythms, and have other benefits.

In addition to unsaturated fatty acids, Brazil nuts contain a good amount of protein, with about four grams per ounce. Like many nuts and seeds, they are a solid source of dietary protein and can be an easy alternative to animal protein. 

However, a potential downside to Brazil nuts is their calories. Brazil nuts have one of the highest amounts of calories per ounce compared to other nuts like almonds (163 cal)3, pistachios (159 cal)4, and cashews (157 cal)5. 

What really makes Brazil nuts stand out from other nuts is their high concentration of selenium—a mineral that helps support immunity and thyroid function. The Recommended Dietary Allowance (RDA) for selenium for men and women ages 19 and older is 55 micrograms6. Li mentions that an ounce of Brazil nuts exceeds selenium needs at 989% of the RDA.

Selenium is naturally found6 in many foods, like Brazil nuts, and it can also be taken as a dietary supplement.

“Selenium is a trace mineral that is essential for human health,” says Maya Feller, MS, RD, CDN, author of Eating from Our Roots. This mineral can assist with reproduction, metabolism of thyroid hormones, protection against infections, and other important tasks. 

Aside from Brazil nuts, other foods that can contain a high amount of selenium include:  

A plausible reason why Brazil nuts have high concentrations of selenium has to do with Brazil’s soil properties. A 2017 study examined the soil near Brazil nut trees in the Amazon rainforest and revealed that the trees were surrounded by soil with high selenium concentrations7. 

To obtain Brazil nuts with the highest selenium concentrations, purchase these raw or roasted seeds from retailers who import them from Brazil.

Selenium increases glutathione peroxidase8, which is an enzyme that helps to reduce inflammation. According to a 2022 study, Brazil nuts' selenium may prevent oxidate damage to DNA9 among people with type 2 diabetes. “Selenium protects the body from oxidative stress,” Li says. After six months of Brazil nut supplementation with selenium, researchers found a significant increase in the participants' fasting blood glucose levels.

Selenium is also important for maintaining normal metabolic function10. Another study published in 2022 involved people with high blood pressure or dyslipidemia (imbalance of lipids). Study participants consumed de-fatted granulated Brazil nuts (GBNs) over three months. The study’s results suggested that Brazil nuts high in selenium could increase plasma selenium levels11 and enzymatic antioxidant activity among people with metabolic disorders. 

A deficiency in selenium can be a contributing factor to a number of metabolic disorders and diseases12 such as cardiovascular disease and cancer.

Though more research is needed, consuming selenium-rich food may be an effective way to prevent cancer.

A 2023 review examined the potential anticancer effects of functional foods containing high amounts of selenium. Although the anticancer effects of selenium require more conclusive research, it’s hypothesized that high doses of selenium may limit the impact of genetic damage and cancer growth in humans13. Another recent review in 2022 suggests that high selenium concentrations can also be chemotherapeutic14.

Selenium is present in many selenoproteins,15 which are proteins that can “help reduce oxidative stress, cellular damage, cardiovascular disease, and some cancers,” Feller adds.

Another possible health benefit of consuming selenium is that it can enhance thyroid function.”[Selenium] is also critical for the proper functioning of the thyroid gland,” Li says. In fact, she adds, the thyroid gland has the highest concentration of selenium6 than any other organ in the body according to the NIH.

Research suggests that the mineral acts as an antioxidant defense16 system within the thyroid. Antioxidants can remove free radicals that are created during thyroid hormone production. 

Li recommends a daily dietary reference intake (DRI) of 55 micrograms (mcg) of Brazil nuts for adults. “If eating Brazil nuts daily, one to two is sufficient, given that the majority of Brazil nuts contain approximately 96 mcg per nut, but some may contain even as high as 400 mcg,” Li adds.

Consuming more than the recommended amount of selenium-rich foods can lead to adverse health outcomes. For example, overconsumption of selenium may cause selenosis. Selenosis, or selenium overexposure, is a poisoning condition that occurs when there’s too much selenium in the blood. Some symptoms that arise from selenium poisoning are:

There are several ways to enjoy Brazil nuts and use them as a natural selenium supplement.

For starters, Brazil nuts can be eaten raw, roasted, ground, or as nut butter. It ultimately depends on your preference as to how you consume these nuts. 

“Personally, I love adding Brazil nuts to my own homemade trail mix, or I garnish my warm bowl of oatmeal or yogurt parfait with one to two Brazil nuts,” Li says. “It's great chopped over a salad as well!”

While Brazil nut trees are not directly sprayed with pesticides, Brazil is considered one of the world’s largest pesticide consumers17. With this in mind, Brazil nuts may still be exposed to pesticides so it’s best to purchase organic Brazil nuts when you can.

To ensure your Brazil nuts stay fresh, Li recommends storing them in the fridge or freezer or a cool, dark area away from direct sunlight. These measures can lengthen shelf life and prevent your Brazil nuts from going rancid.

Brazil nuts are unique nuts because they contain high concentrations of selenium—a mineral that has multiple health benefits, such as preventing cell damage and improving thyroid function. Like any food, Brazil nuts should be consumed in moderation because overconsumption can lead to unpleasant side effects. However, as long as you eat the recommended amount of Brazil nuts (1-2 per day), you can safely reap the nutritional benefits of this nut.

Hungry for more? Check out the healthiest nuts to mix up your trail mix and take a deep dive into the nutritional value of cashews and pecans versus walnuts.