NutriDex

The Supplement Research Compendium
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Brazil Nut

Bertholletia excelsa

Selenium-rich tree nut; 1-2 nuts/day for lipids, but easy to overdose

Preliminary evidence 🥜Nuts🫀Heart & Metabolic⏳Longevity

✚ Updated · How we grade evidence

Evidence tier
Preliminary
Research weight
Citations
10 verified / 10
Classification
Nuts
❝
What the evidence says. Early or small human trials; promising but not yet conclusive.

Nutrition per serving 1 oz (28 g, ~6 nuts)

28gSERVING
  • Sugars 0.7 g3%
  • Fibre 2.1 g8%
  • Other carbs 0.5 g2%
  • Protein 4 g14%
  • Fat 18.8 g67%
  • Other 1.9 g7%
What's in one serving, by weight — average composition (USDA).
Fiber8%Protein8%Vitamin E11%Magnesium25%Copper54%Manganese15%Zinc10%Selenium100%+
One serving as % of the adult daily requirement (FDA Daily Values). The bold outer ring = 100% of a day's needs.
184 kcal4 g protein2.1 g fiber19 g fat
NutrientPer serving% daily value
Fiber2.1 g8%
Protein4 g8%
Vitamin E1.6 mg11%
Magnesium105 mg25%
Copper0.49 mg54%
Manganese0.34 mg15%
Zinc1.1 mg10%
Selenium537 µg976%
Phosphorus203 mg16%
Potassium185 mg4%
Iron0.68 mg4%
Calcium45 mg3%
Folate6 µg2%

Composition data: USDA FoodData Central ↗

What is Brazil Nut?

Brazil Nut (Bertholletia excelsa) is a nut or seed used for modest reductions in total and ldl cholesterol in small rcts. NutriDex grades the human evidence as Preliminary. Brazil nuts are the most concentrated dietary source of selenium, and most of the specific human research focuses on that. Small randomized trials suggest a modest benefit: a 90-day RCT of partially defatted Brazil nut flour in dyslipidemic patients lowered total and non-HDL cholesterol (Carvalho 2015, PMID 26077768), and a trial in obese adolescents reduced total/LDL cholesterol and oxidized LDL (Maranhao 2011, PMID 21619692). A 2022 systematic review and meta-analysis of RCTs found Brazil nuts reliably raise selenium status but showed inconsistent, generally small effects on blood lipids (PMID 35204285). Evidence is preliminary and rests on small, short trials; there are no Brazil-nut-specific outcome trials for cardiovascular events or mortality. The stronger cardiovascular and all-cause mortality data come from tree nuts as a whole and from large cohorts (Aune 2016 meta-analysis, PMID 27916000), not Brazil nuts specifically. Treat them as one nutritious nut among many, valued chiefly for selenium.

Purported Benefits

✓Modest reductions in total and LDL cholesterol in small RCTs
✓Dramatically raises blood selenium status from a tiny serving
✓Lowers oxidized LDL and markers of oxidative stress in trial subjects
✓Part of the broader tree-nut pattern linked to lower CVD risk in cohorts
✓Provides healthy unsaturated fats, fibre and magnesium
✓May modestly improve antioxidant/inflammatory biomarkers

Dosing & Compounds

Typical Dose
1-2 nuts (~5-10 g) per day; even a single nut supplies ~70-90 mcg selenium. Do not exceed 3-4 nuts daily.
Active Compounds
Selenium (selenocysteine/selenomethionine)Monounsaturated fat (MUFA)Polyunsaturated fat (PUFA, linoleic acid)Vitamin E (tocopherols)MagnesiumPhytosterolsDietary fibreL-arginine

Safety & Cautions

Tree nuts are a major allergen and can cause life-threatening anaphylaxis; avoid if allergic to tree nuts. Brazil nuts are calorie-dense (~185 kcal/oz), so portion control matters. The dominant Brazil-nut-specific risk is selenium toxicity (selenosis): a single nut can contain 70-90 mcg selenium, so just a few nuts can exceed the 400 mcg/day tolerable upper limit, causing hair loss, brittle nails, GI upset, garlic breath, fatigue and neuropathy. Limit to 1-3 nuts per day and do not combine with selenium supplements. Whole nuts are a choking hazard for young children. Brazil nuts can also concentrate naturally occurring radium and barium from soil; this is not a practical concern at normal intakes but is another reason not to over-consume. Educational only — always check with your doctor or pharmacist before combining Brazil Nut with any medicine.

Key Studies ★ 10 studies

Meta-analysis Cardoso 2022 systematic review/meta-analysis of RCTs ✓ PubMed
Brazil nuts consistently increased blood selenium but had inconsistent, generally modest effects on blood lipids and oxidative/inflammatory markers across randomized trials.
meta-analysis Godos 2022 ✓ Full text
Meta-analysis of 8 RCTs: Brazil nut intake markedly raised plasma selenium (SMD 6.93, 95% CI 3.99-9.87) but did not significantly change total cholesterol (SMD -0.22, 95% CI -0.57 to 0.14) or LDL (SMD -0.15, 95% CI -0.43 to 0.13).
Meta-analysis Aune 2016 dose-response meta-analysis (BMC Medicine) ✓ PubMed
Across 20 prospective cohorts, higher nut intake (~28 g/day) was associated with lower cardiovascular disease and all-cause mortality; reflects nuts broadly, not Brazil nuts specifically.
meta-analysis Aune 2016 ✓ Full text
Dose-response meta-analysis of 20 prospective cohorts (up to 819,448 participants): each 28 g/day of nuts was associated with lower coronary heart disease (RR 0.71, 95% CI 0.63-0.80), cardiovascular disease (RR 0.79), and all-cause mortality (RR 0.78).
RCT Carvalho 2015 RCT (Nutrition Journal) ✓ PubMed
In 91 dyslipidemic/hypertensive patients, 13 g/day partially defatted Brazil nut flour for 90 days reduced total cholesterol and non-HDL cholesterol versus placebo.
RCT Carvalho 2015 ✓ Full text
RCT in hypercholesterolemic adults: partially defatted Brazil nut flour reduced total cholesterol (-20.5 mg/dL, P=0.02) and non-HDL cholesterol (-19.5 mg/dL, P=0.02) and preserved free T3.
RCT Cardoso 2016 ✓ Source
RCT pilot in older adults with mild cognitive impairment: ~1 Brazil nut/day for 6 months raised selenium status and improved verbal fluency (P=0.007) and constructional praxis (P=0.031) vs control.
RCT Maranhao 2011 RCT (Nutr Metab Cardiovasc Dis) ✓ PubMed
In obese female adolescents, 15-25 g/day Brazil nuts for 16 weeks raised selenium and reduced total cholesterol, LDL cholesterol and oxidized LDL.
RCT Colpo 2013 ✓ Full text
Randomized crossover in 10 healthy adults: a single 20-50 g serving of Brazil nuts lowered serum LDL-C and raised HDL-C by 9 h, with changes persisting up to 30 days.
RCT Thomson 2008 ✓ PubMed
RCT in 59 NZ adults: 2 Brazil nuts/day (~53 ug Se) for 12 weeks raised plasma selenium 64.2% and whole-blood glutathione peroxidase 13.2%, matching or exceeding 100 ug selenomethionine.
10 sources cited · 10 verified Search all studies on PubMed ↗

Common questions about Brazil Nut

What is Brazil Nut used for?

Brazil Nut is most often taken for Modest reductions in total and LDL cholesterol in small RCTs, Dramatically raises blood selenium status from a tiny serving, Lowers oxidized LDL and markers of oxidative stress in trial subjects, Part of the broader tree-nut pattern linked to lower CVD risk in cohorts. Selenium-rich tree nut; 1-2 nuts/day for lipids, but easy to overdose

Does Brazil Nut work — what does the evidence say?

Preliminary evidence. Early or small human trials; promising but not yet conclusive. Brazil nuts are the most concentrated dietary source of selenium, and most of the specific human research focuses on that. Small randomized trials suggest a modest benefit: a 90-day RCT of partially defatted Brazil nut flour in dyslipidemic patients lowered total and non-HDL cholesterol (Carvalho 2015, PMID 26077768), and a trial in obese adolescents reduced total/LDL cholesterol and oxidized LDL (Maranhao 2011, PMID 21619692). A 2022 systematic review and meta-analysis of RCTs found Brazil nuts reliably raise selenium status but showed inconsistent, generally small effects on blood lipids (PMID 35204285). Evidence is preliminary and rests on small, short trials; there are no Brazil-nut-specific outcome trials for cardiovascular events or mortality. The stronger cardiovascular and all-cause mortality data come from tree nuts as a whole and from large cohorts (Aune 2016 meta-analysis, PMID 27916000), not Brazil nuts specifically. Treat them as one nutritious nut among many, valued chiefly for selenium.

What is the typical dose of Brazil Nut?

1-2 nuts (~5-10 g) per day; even a single nut supplies ~70-90 mcg selenium. Do not exceed 3-4 nuts daily.

Is Brazil Nut safe? Any cautions or side effects?

Tree nuts are a major allergen and can cause life-threatening anaphylaxis; avoid if allergic to tree nuts. Brazil nuts are calorie-dense (~185 kcal/oz), so portion control matters. The dominant Brazil-nut-specific risk is selenium toxicity (selenosis): a single nut can contain 70-90 mcg selenium, so just a few nuts can exceed the 400 mcg/day tolerable upper limit, causing hair loss, brittle nails, GI upset, garlic breath, fatigue and neuropathy. Limit to 1-3 nuts per day and do not combine with selenium supplements. Whole nuts are a choking hazard for young children. Brazil nuts can also concentrate naturally occurring radium and barium from soil; this is not a practical concern at normal intakes but is another reason not to over-consume.

How many studies support Brazil Nut?

NutriDex cites 10 sources for Brazil Nut, graded "Preliminary".

Cite this page
APA

Peh, D. (2026). Brazil Nut (Bertholletia excelsa): Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 26 Jun 2026, from https://nutridex.info/s/brazil-nut

BibTeX
@misc{nutridex_brazil_nut,
  author       = {Peh, Daryl},
  title        = {Brazil Nut (Bertholletia excelsa): Benefits, Dosage, Side Effects \& Evidence},
  year         = {2026},
  howpublished = {NutriDex --- The Supplement Research Compendium},
  url          = {https://nutridex.info/s/brazil-nut},
  note         = {Reviewed by Dr Daryl Peh, MBBS Singapore, MMed FM. Accessed 2026-06-26}
}

For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.

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