One Brazil nut a day is a conservative amount for most healthy adults; two can be reasonable, but regular intake above two risks exceeding selenium limits.
A single Brazil nut can deliver more selenium than your body needs in an entire day. How much is safe depends on how much selenium each nut carries — and that number swings wildly from one batch to the next.
How Much Selenium Is In One Brazil Nut?
Brazil nuts contain roughly 68 to 91 micrograms (mcg) of selenium per nut, while USDA’s FoodData Central averages 544 mcg per ounce. Both figures are correct — they measure different things.
One nut can meet or exceed the adult Recommended Dietary Allowance (RDA) of 55 mcg. Two large or selenium-rich nuts can supply roughly 136 to 182 mcg before you count selenium from any other food or supplement.
Selenium concentration depends on the soil, the nut’s origin, its size, and the batch — so a handful from one bag can behave very differently from another.
What Are The Daily Selenium Limits?
The U.S. adult RDA is 55 mcg per day, and the adult Tolerable Upper Intake Level (UL) is 400 mcg per day from all sources — food and supplements combined. The European Food Safety Authority’s adult upper level cited in the literature is stricter, at 255 mcg per day.
A 2025 review notes that one or two nuts daily are commonly recommended, and that more than two may exceed the European upper level. A 2019 peer-reviewed analysis concluded that a single roughly 5-gram nut could meet or exceed the RDA, and suggested reducing a typical 30-gram serving to about 15 grams — roughly three nuts — unless low selenium content could be demonstrated.
| Amount Eaten | Typical Selenium Range | Standing Against Daily Limits |
|---|---|---|
| 1 nut | 68–91 mcg | Meets or exceeds the 55 mcg RDA; far below the 400 mcg U.S. UL |
| 2 nuts | 136–182 mcg | Still under the U.S. UL, but can pass the 255 mcg EFSA level once other foods are counted |
| 3 nuts | 204–273 mcg | Can cross the EFSA adult upper level on nuts alone |
| 6 nuts (one 30 g serving) | 840–1,470 mcg in tested batches | Multiple times over the 400 mcg U.S. UL |
| 1 ounce (by weight) | 544 mcg on average per USDA | Exceeds the U.S. UL before any other source is added |
Which Mistakes Push You Over The Limit?
The most common error is treating six nuts as a routine serving. If you’re figuring out how they fit your routine, this breakdown of the best time to eat brazil nuts covers how timing fits alongside your daily intake.
Counting only supplements is another trap — the 400 mcg UL covers food and supplements together, so a multivitamin or selenium pill plus a few nuts adds up fast. Assuming every nut holds the same amount is equally risky. Some people also confuse the RDA with a target to maximize; more selenium isn’t automatically better, and chronic excess causes selenosis, with symptoms including hair loss or brittle hair, brittle or thickened nails, skin abnormalities, garlic-like breath odor, a metallic taste, nausea, diarrhea, fatigue, and nervous-system problems.
A practical approach: start with one nut, and account for selenium from seafood, meat, eggs, dairy, enriched grains, multivitamins, and selenium supplements. If you eat two, skip the selenium supplement unless a clinician has recommended that combination. Check the package’s serving size and nutrition label, but recognize that selenium often isn’t listed and that label values can’t capture natural batch variation. The NIH Office of Dietary Supplements publishes the full selenium intake and safety reference these limits come from.
Anyone with a selenium-containing supplement regimen, a relevant medical condition, pregnancy-related nutrition concerns, or symptoms of excess should talk to a healthcare professional before eating Brazil nuts regularly.
Common Questions
Can eating too many Brazil nuts make you sick?
Yes. Chronically exceeding the 400 mcg daily upper limit can cause selenosis, marked by hair loss, brittle nails, garlic-like breath odor, nausea, and nervous-system issues.
Do I need Brazil nuts if I already take a multivitamin?
Probably not daily. Most multivitamins and many enriched foods already supply selenium, and the 400 mcg upper limit counts food and supplements together. If your multivitamin contains selenium, one nut occasionally is plenty — adding nuts on top of a selenium pill can push total intake toward unsafe levels.
Is one nut really enough selenium for a whole day?
For most adults, yes. The RDA is 55 mcg per day, and a single Brazil nut supplies roughly 68 to 91 mcg. That covers your daily need on its own, which is why these nuts work better as a measured one-or-two-a-day habit than as an open snack.
Sources
- NIH Office of Dietary Supplements. “Selenium—Consumer Fact Sheet.” Supports the 55 mcg RDA, the 400 mcg upper limit, and selenosis symptoms.
- NIH Office of Dietary Supplements. “Selenium—Health Professional Fact Sheet.” Source for clinical intake limits and selenium content figures.
- Linus Pauling Institute. “Selenium.” Background on selenium sources, variability, and toxicity risk.