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Brazil nuts are the richest food source of selenium you can find in a grocery store. USDA data put a single nut at about 96 micrograms (mcg) of selenium, roughly 174% of the Daily Value, and a 1-ounce handful of about six nuts at more than nine times the Daily Value. That is useful to know in both directions: a few Brazil nuts cover your selenium needs, and eating them in large amounts every day can push you past the official upper limit. Below are the USDA nutrition facts, how much the selenium in each nut varies, what the research shows, and who should keep count.
Peptide Labs does not sell Brazil nuts or selenium supplements linked here. This article is general nutrition information, not medical advice.
Key Takeaways
- USDA lists about 96 mcg of selenium in one Brazil nut and about 543 mcg in a 1-ounce serving.
- NIH gives a range of 68 to 91 mcg per nut and says values vary widely with the soil the trees grow in.
- The adult upper limit for selenium is 400 mcg a day from all sources; for children it is far lower.
- Regularly eating Brazil nuts in large amounts could cause selenium toxicity, according to NIH.
- Brazil nuts also supply copper and magnesium and carry more saturated fat than most other nuts.
Brazil nuts nutrition: USDA chart
The values below come from the USDA FoodData Central SR Legacy entry for dried, unblanched Brazil nuts (FDC ID 170569), converted from the per-100-gram figures to a 1-ounce serving, which USDA lists as about six kernels. The percent Daily Value (%DV) uses the FDA Daily Values for food labels.
| Nutrient | Per 1 oz (28 g, about 6 nuts) | % Daily Value |
|---|---|---|
| Calories | 187 | n/a |
| Protein | 4.1 g | 8% |
| Total fat | 19.0 g | 24% |
| Saturated fat | 4.6 g | 23% |
| Fiber | 2.1 g | 8% |
| Selenium | 543 mcg | 988% |
| Copper | 0.49 milligrams | 55% |
| Magnesium | 107 milligrams | 25% |
| Phosphorus | 206 milligrams | 16% |
| Manganese | 0.35 milligrams | 15% |
| Thiamin | 0.17 milligrams | 15% |
| Vitamin E | 1.6 milligrams | 11% |
| Zinc | 1.2 milligrams | 10% |
Selenium is the headline, but the chart also shows a solid amount of copper and magnesium; our list of foods high in magnesium puts Brazil nuts in context, and our copper guide explains what copper does. One point that surprises people: Brazil nuts carry about 4.6 grams of saturated fat per ounce in USDA data, compared with about 1.7 grams for walnuts and 1.1 grams for almonds. Most of their fat is still unsaturated, but they are not interchangeable with every other nut.
Brazil nut selenium: how much is in one nut?
There is no single answer, and that is the main reason to be careful. USDA’s average works out to about 96 mcg per 5-gram kernel. The NIH Office of Dietary Supplements (ODS) quotes 68 to 91 mcg per nut and notes that, while USDA averages 544 mcg per ounce, other analyses vary widely. The reason is soil: Brazil nut trees take up selenium from the ground, and selenium levels in soil differ from one part of the Amazon to another. A New Zealand trial published in 2008 illustrates the point. The researchers expected a set amount of selenium from the nuts they provided, but when they analyzed the batch, the nuts delivered only about half of that on average, with a wide possible range.
For comparison, here is how a Brazil nut stacks up against other selenium sources in the same USDA database.
| Food (USDA description, shortened) | Serving | Selenium, mcg | % Daily Value |
|---|---|---|---|
| Brazil nuts, dried | 1 oz (about 6 nuts) | 543 | 988% |
| Brazil nut, dried | 1 nut (5 g) | 96 | 174% |
| Halibut, cooked | 3 oz (85 g) | 47 | 86% |
| Sardines, canned in oil | 3 oz (85 g) | 45 | 81% |
| Chicken breast, roasted | 3 oz (85 g) | 23 | 43% |
| Chia seeds, dried | 1 oz (28 g) | 16 | 28% |
| Egg, hard-boiled | 1 large (50 g) | 15 | 28% |
| Sunflower seed kernels, dried | 1 oz (28 g) | 15 | 27% |
| Cashews, raw | 1 oz (28 g) | 6 | 10% |
| Walnuts, English | 1 oz (28 g) | 1 | 3% |
The selenium upper limit
The Tolerable Upper Intake Level (UL) is the most a person can take in daily over the long term without expecting harm. For selenium it counts food, drinks and supplements together. The Recommended Dietary Allowance (RDA) for adults is 55 mcg, the same as the Daily Value, so the adult UL is a little more than seven times the RDA. These are official reference values from the Food and Nutrition Board as listed by ODS, not personal targets.
| Age group | Selenium UL, mcg per day |
|---|---|
| Children 1 to 3 | 90 |
| Children 4 to 8 | 150 |
| Children 9 to 13 | 280 |
| Teens 14 to 18 | 400 |
| Adults, including pregnancy and breastfeeding | 400 |
Two details matter here. For a toddler, the UL of 90 mcg is about what ODS lists for a single nut, so Brazil nuts are a food to portion carefully for young children. And in 2023 the European Food Safety Authority set a lower adult upper level, 255 mcg, which shows how close the margin can be. ODS describes the signs of chronically high selenium intake, called selenosis: garlic breath and a metallic taste come first, and hair loss and brittle or lost nails are the most common signs, along with rash, nausea, diarrhea, fatigue and irritability. Our selenium guide covers the mineral itself in more depth.
How many Brazil nuts a day?
No official body publishes a daily Brazil nut count, so the honest answer is a calculation rather than a number. With ODS figures of 68 to 91 mcg per nut and an adult UL of 400 mcg from all sources, a full 1-ounce serving already goes past the adult limit on its own, before you count bread, eggs, meat, seafood or a multivitamin. The UL describes long-term daily intake, so an occasional handful is a different situation from a daily habit. ODS puts it plainly: Brazil nuts could cause selenium toxicity if consumed regularly. If you eat them often, take a selenium-containing supplement, or are feeding children, ask your clinician or a registered dietitian what makes sense for you.
Brazil nuts benefits: what the research shows
The clearest finding is that Brazil nuts raise selenium status. In the 2008 trial in the American Journal of Clinical Nutrition, 59 adults in New Zealand, a country with low-selenium soils, ate Brazil nuts, took a selenomethionine supplement or took a placebo for 12 weeks. Blood selenium rose by about 64% with the nuts and 61% with the supplement, compared with about 8% with placebo, and the activity of the selenium-dependent enzyme glutathione peroxidase rose more in the nut group. The authors concluded that the nuts worked as well as the supplement for improving selenium status in that population.
Keep the context in mind. ODS reports that most people in the US already get enough selenium from food, and large trials of selenium supplements in people with adequate intakes did not deliver the hoped-for results, as our selenium guide explains. Raising selenium further is not a benefit for someone who is not low. Beyond selenium, Brazil nuts are an energy-dense food with protein, fiber and unsaturated fat, and they fit the same place in a diet as other nuts. For protein-focused swaps, see our list of high protein foods.
Where Brazil nuts come from
Brazil nuts are the seeds of Bertholletia excelsa, a giant tree of the Amazon lowland forests in Brazil, Peru and Bolivia. According to University of Florida researchers involved in a 2003 study in Science, the nuts come from wild trees because plantations have not been successful, and the study found that young trees were virtually absent where seeds had been collected persistently for decades. Wild harvest is one more reason selenium content varies from batch to batch.
Who should be careful with Brazil nuts
- People with a tree nut allergy: FDA lists Brazil nut among the tree nuts it considers major food allergens, so it must be declared on packaged food labels.
- Children: selenium ULs are much lower for kids, starting at 90 mcg for ages 1 to 3.
- Anyone taking selenium in a supplement: multivitamins, mineral blends and thyroid or hair formulas often list selenium. Add up every label; our third-party testing guide explains quality seals.
- People watching calories: one ounce has about 187 calories in USDA data.
- Anyone with garlic breath, a metallic taste, or new hair or nail changes who eats Brazil nuts often: stop guessing and talk to a clinician.
Comparing nuts? Our guide to walnuts covers the nut with the most plant omega-3 fat, which is a very different nutrient profile.
Frequently Asked Questions
How much selenium is in one Brazil nut?
USDA’s average works out to about 96 mcg per nut, and NIH quotes 68 to 91 mcg. Actual amounts vary widely with the soil where the tree grew.
How many Brazil nuts a day is too many?
There is no official nut count. A 1-ounce serving of about six nuts already exceeds the adult upper limit of 400 mcg of selenium, and NIH warns that regular large amounts could cause toxicity.
What are the signs of too much selenium?
NIH lists garlic breath and a metallic taste as early signs, and hair loss and brittle or lost nails as the most common, plus rash, nausea, diarrhea, fatigue and irritability.
Are Brazil nuts good for kids?
They can be part of a varied diet, but the selenium upper limit for a child aged 1 to 3 is 90 mcg, about the amount in one nut, so portions need care. Whole nuts are also a choking risk for young children.
Do Brazil nuts have a lot of saturated fat?
More than most nuts: about 4.6 grams per ounce in USDA data, compared with 1.7 grams for walnuts. Most of their fat is still unsaturated.
Can I replace a selenium supplement with Brazil nuts?
A 2008 trial found Brazil nuts raised selenium status as well as a supplement, but their selenium content is unpredictable. Ask your clinician before changing anything you were advised to take.
Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines, are pregnant or are shopping for a child. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed October 2026.
Related guides: Selenium Benefits: What Trials Found, Food Sources and Toxicity, Walnuts Benefits: Nutrition Facts, ALA and What the Studies Show, Almonds Benefits: USDA Nutrition per Ounce, Calories and Research.