Brazil nut

Other Names

almendraalmendrasalmendroAmazonenmandelamendoeira-da-américaavellana del BrasilBarthollesia excelsaBarthollesia excelsa Silva MansoBertholletia excelsaBertholletia excelsa Bonpl.Bertholletia excelsa Humb. & Bonpl.Bertholletia excelsa KunthBertholletia excelsa O.BergBertholletia nobilisBertholletia nobilis MiersBrasil de IpakBrasilianische KastanieBrasilnussBrazil-nut treeBraziliaansche nootBrazilnutBrazilnut-treecastagna del Brasilecastaña de montecastaña de Parácastaña del Brasilcastaña del Marañóncastanhacastanha-da-amazôniacastanha-do-acrecastanha-do-Brasilcastanha-do-brazilcastanha-do-maranhãocastanha-do-parácastanha-mansacastanha-verdadeiracastanheiracastanheira-do-maranhãocastanheira-do-parácastanheirocastañocastaño de Brasilchâtaignier du Brésilcoquito de Brasilcream nutcream nutsIpaknajuviaMarahonkastanienoce amazzonicanoce brasiliananoce del Brasilenoix du Brésilnoz amazônicanoz-do-Brasilnuez amazónicanuez boliviananuez de Brasilnuez de Paránuez del AmazonasPara nutPará nutPara nutsParanussParanussbaumsapucaiasprencioloSteinnusstocaritururi

Synopsis

Brazil Nut (Bertholletia excelsa): A Comprehensive Reference

1. Identity and Botanical Classification

Scientific and Common Names

The Brazil nut tree belongs to the genus Bertholletia, a monotypic genus in the family Lecythidaceae, and its only species, Bertholletia excelsa H.B.K., produces the large, oil-rich seeds known as Brazil nuts. In 1808, the species was formally described as Bertholletia excelsa by Humboldt and Bonpland, based on specimens they collected on the banks of the Orinoco River. In Portuguese-speaking Brazil, the nut is widely known as castanha-do-Pará or castanha-do-Brasil. Although first discovered in what is now Venezuela, the species became known worldwide as the "Brazil nut" because Brazil has historically been one of the main exporters of its seeds.

Botanical Description and Ecology

The Brazil nut comes from colossal trees up to 60 m tall (200 ft) and 16 m in circumference (53 ft), which are found in discontinuous patches throughout the Amazon basin. The Brazil nut tree is native to the Amazon rainforest. It is the most important non-timber commercial product of the South American rainforest, with an annual harvest in Brazil alone of over 25,000 tons employing some 200,000 people. Unlike most commercially important seed crops, harvesting is done exclusively in the wild in natural forests, preserving the fragile ecological balance of this unique region.

Common Forms and Preparations

Brazil nuts are consumed and commercially distributed in several forms:

Raw whole kernels — the most prevalent retail form, sold in-shell or shelled.
Roasted kernels — dry- or oil-roasted, commonly found in mixed nut products.
Brazil nut flour (defatted) — defatted Brazil nut flour, obtained as a by-product of oil pressing, serves as a valuable nutraceutical ingredient due to its high protein content, essential minerals — particularly selenium — and amino acids.
Brazil nut oil — cold-pressed for culinary and cosmetic use.
Brazil nut beverage ("Brazil nut milk") — a food sector known as "Brazil nut milk" has emerged as a plant-based alternative beverage to dairy, promoted for its health-enhancing properties.
Brazil nut butter — ground paste analogous to other nut butters, used in clinical trials as a vehicle for selenium delivery.

2. Traditional and Historical Use

Indigenous Amazonian Cultures

The Brazil nut (Bertholletia excelsa) is a central food in the Tenharin cuisine, a Tupi Kagwahiva people from the south of Amazonas, Brazil. Present in several dishes consumed in ritual and daily contexts, the nut is called the "chief of meals" and "what gives life a taste." Indigenous tribes across the Amazon — such as the Kayapó, Yanomami, and Xikrin — were among the first to harvest and consume Brazil nuts; archaeological findings suggest the nuts were part of native diets for over 11,000 years, based on charred remains found in early human settlements.

Recent scientific studies show that Brazil nut groves have been managed, facilitated, and probably spread throughout the Amazon by indigenous peoples since before European conquest. These orchards are present throughout indigenous territories, especially near ancient villages and areas of Amazonian Dark Earths that attest to the traditionality of their secular management.

Indigenous communities used Brazil nuts in multiple ways. They were very likely consumed raw, grated into gruels, and even formed the basis of a bread called "chappa" in some communities. Main ritual dishes among the Tenharin include tapir meat cooked in Brazil nut milk and the "mbotawa," a baked Brazil nut cake with vegetal salt. The high oil content was extracted for cooking, illumination, and soap making. In traditional medicine, the seedpod husks were used to brew teas for stomach issues.

The Brazil nut, or castana, has been an integral part of Amazonian culture for centuries, featuring prominently in the diet, rituals, and folklore of indigenous communities. The Brazil nut tree is considered sacred in some communities, symbolizing strength, resilience, and longevity. It plays a vital role in traditional practices, including diet, medicine, and spiritual rituals, and its harvest is often a communal effort that reinforces social bonds.

European Discovery and Spread

With the arrival of European explorers in the 16th century, many native plants and resources — including Brazil nuts — began to attract foreign interest. Long before it was recorded by European science, the Brazil nut tree was known and used by indigenous peoples of the Amazon. From the Iberian Peninsula, trade in Brazil nuts expanded across Europe; by the 18th century the nut was documented in botanical collections. Today, Bolivia is reported as the main producer, followed by Peru and Brazil.

3. Key Constituents and Active Compounds

Macronutrient Profile

Brazil nuts typically contain 60–70% lipids, 14–17% proteins, and 10–16% carbohydrates. They are also rich in organic nutrients including protein, fiber, thiamin, niacin, pyridoxine, vitamin E, and essential minerals such as calcium (Ca), magnesium (Mg), iron (Fe), potassium (K), copper (Cu), zinc (Zn), and phosphorus (P).

Selenium

Brazil nuts (Bertholletia excelsa) natively contain very high concentrations of selenium. Brazil nuts are consumed worldwide and are known as the richest food source of selenium (Se). Mean Se levels have been measured between 28 and 49 mg kg⁻¹, with up to 8-fold seed-to-seed variation within batches. Brazil nut selenium is mainly in organic form; while present throughout the seed, selenium is most concentrated in a ring 1 to 2 mm below the surface.

The median Se concentration in Brazil nuts varies from 2.07 mg kg⁻¹ (in Mato Grosso state) to 68.15 mg kg⁻¹ (in Amazonas state). Depending on its origin, a single Brazil nut could provide from 11% (in Mato Grosso state) up to 288% (in Amazonas state) of the daily Se requirement for an adult man (70 μg).

Nuclear magnetic resonance (NMR) spectroscopy has revealed that selenium in Brazil nuts occurs predominantly as selenomethionine (SeMet), alongside phytate, amino acids, peptides, and other polar low-molecular-weight compounds. Most selenium content in the nut is present in the protein fractions, with the highest amount presented as selenomethionine and selenocysteine. Selenium in Brazil nuts is highly bioaccessible (approximately 85%).

Lipids and Fatty Acids

All Brazil nut oils show similar fatty acid and acylglycerol profiles, with a predominance of linoleic and oleic acids (greater than 78% m/m) and high triacylglycerol content (greater than 96% m/m). The most abundant monounsaturated fatty acid is oleic acid (C18:1), while linoleic acid (C18:2) is the most prevalent polyunsaturated fatty acid. Brazil nuts are very rich in β-tocopherol (88.3%), unsaturated free fatty acids, monounsaturated fatty acids — linoleic acid (39.3%) and linolenic acid (36.1%) — and β-sitosterol (76%) and other phytosterols.

Tocopherols (Vitamin E)

The composition of Brazil nuts includes bioactive minor lipid components such as β-sitosterol, γ-tocopherol, and α-tocopherol. Tocopherols are among the bioactive constituents of nuts that elicit cardioprotective effects.

Phytosterols

β-Sitosterol is the most prevalent phytosterol in Brazil nuts. The nut contains tocopherols (α and γ) and phytosterols such as β-sitosterol and stigmasterol, with considerable amounts of campesterol. Phytosterols can reduce both total cholesterol and inflammatory biomarkers, decreasing the risk of atherosclerosis and thrombosis.

Squalene

Brazil nuts contain notably high levels of squalene — 1,377.8 mg/g oil — the highest among the nut species studied (brazil, pecan, pine, pistachio, and cashew).

Phenolic Compounds

Twenty-four phenolic compounds have been identified in Brazil nuts and their products; flavan-3-ols and hydroxybenzoic acids are the most abundant phenolics. Identified phenolics include catechin and its glycosides, epicatechin and its glycosides, quercetin, myricetin-3-O-rhamnoside, gallic acid and derivatives, 4-hydroxybenzoic acid, ellagic acid, vanillic acid, p-coumaric acid, and ferulic acid.

Other Minerals

Brazil nuts are rich in magnesium, selenium, arginine and other amino acids, dietary fiber, tocopherols (vitamin E), phytosterols, linoleic acid, linolenic acid, sitosterols, monounsaturated and polyunsaturated fatty acids, and polyphenols. Besides selenium, Brazil nuts present relevant content of other micronutrients such as magnesium, copper, and zinc.

Naturally Occurring Non-Nutrient Elements: Barium and Radium

Brazil nuts also contain potentially harmful elements, including barium (Ba), and exhibit an unusual capacity to accumulate radioactive radium (Ra). A global literature review found a mean barium level in Brazil nuts of 1.27 mg/g (95% CI: 0.89, 1.64; range: 0.03–5.89). Barium and radium — both chemo- and/or radiotoxic — exhibit low bioaccessibility (approximately 2% each). Brazil nuts stand out from other nuts in terms of their high (albeit highly variable) radium content. The radium isotopes Ra-226 and Ra-228 emit alpha- and beta-radiation, with this type of radiation being particularly harmful when ingested.

4. Mechanisms of Action

Selenoprotein Synthesis and Antioxidant Defense

Selenium is an essential trace element, being a part of about 25 selenoproteins in mammals, which are crucial to several metabolic functions including oxidative stress balance and redox signaling. However, the health effects of selenium are confined to a narrow intake range. Selenium functions as a component of many selenoproteins in antioxidant and redox reactions. In particular, selenium is necessary for the functioning of glutathione peroxidase (GPx), an antioxidant enzyme that catalyzes hydrogen peroxide and lipid hydroperoxide through glutathione metabolism. GPx protects membrane lipids and other cellular and extracellular components from oxidative damage, and selenium has been hypothesized to exert anti-atherogenic effects by lowering oxidative stress in the endothelium.

Thyroid Hormone Metabolism

Selenium is an essential micronutrient for the metabolism of thyroid hormones, playing a major role in thyroxine (T4) conversion to the more active metabolic form triiodothyronine (T3) because the activity of some deiodinases is dependent on selenium. The thyroid gland contains the highest amount of selenium, and the selenoprotein glutathione peroxidase can protect the thyroid gland from oxidative damage produced during thyroid hormone synthesis.

Cardiovascular Mechanisms

Due to their rich mixture of nutrients, Brazil nuts protect LDL from peroxidation and improve endothelial function, blood pressure, lipid metabolism, and decrease endothelial inflammatory markers, DNA oxidation, and blood lipids (cholesterol, LDL, triglycerides). The composition of monounsaturated and polyunsaturated fatty acids and fiber of Brazil nuts is responsible for their protective effect against cardiovascular diseases.

Bioavailability of Selenium

The nutritional biopotency of selenium in Brazil nuts was evaluated by measuring the restoration of two selenoenzymes — glutathione peroxidase and type I 5'-deiodinase — in selenium-deficient rats. Supplementation with Brazil nuts as the sole source of selenium produced efficient gradient of enzyme restoration at 0.05–0.2 μg/g of dietary selenium. A parallel comparison with sodium selenite indicated that selenium in Brazil nuts and selenite selenium are equally bioactive. Consumption of Brazil nuts for 2 months in one study was effective in improving selenium biomarkers; these data support the evidence that selenium content in the nut is highly bioavailable.

5. Scientific Evidence by Area of Use

5.1 Selenium Status and Deficiency Correction

Evidence strength: Strong for raising selenium status.

A randomized controlled trial was conducted with 59 New Zealand adults. Participants consumed 2 Brazil nuts thought to provide approximately 100 μg Se, 100 μg Se as selenomethionine, or placebo daily for 12 weeks. Actual intake from nuts averaged 53 μg Se/d (possible range: 20–84 μg Se). Plasma selenium and plasma and whole blood glutathione peroxidase (GPx) activities were measured at baseline and at 2, 4, 8, and 12 weeks. Plasma selenium increased by 64.2%, 61.0%, and 7.6%; plasma GPx by 8.3%, 3.4%, and −1.2%; and whole blood GPx by 13.2%, 5.3%, and 1.9% in the Brazil nut, selenomethionine, and placebo groups, respectively.

That study was the first to investigate the response of both blood selenium concentration and activity of the selenoprotein GPx to Brazil nut supplementation in humans, demonstrating that consumption of 2 Brazil nuts daily is as effective in raising plasma selenium concentration and GPx activities as a 100-μg selenium selenomethionine supplement during 12 weeks.

A subsequent systematic review and meta-analysis of eight randomized clinical trials found a significant positive effect of Brazil nuts on selenium blood concentration (SMD = 6.93, 95% CI: 3.99; 9.87). The findings provide certain evidence of the effects of Brazil nuts in influencing selenium status and improving antioxidant defenses through the impact on glutathione peroxidase.

More than a billion people worldwide may be selenium-deficient, and supplementation with Se-rich Brazil nuts may be a good strategy to prevent deficiency. Brazil nuts are well known for their extraordinarily high selenium content. For this reason, they are frequently recommended as a natural selenium "supplement," particularly for certain population groups such as vegetarians and vegans in regions with low soil selenium levels. Typically, an intake of one or two Brazil nuts per day is recommended.

5.2 Cardiovascular Health and Lipid Metabolism

Evidence strength: Preliminary and mixed; some positive signals in specific populations.

The findings of one systematic review and meta-analysis provide certain evidence of the effects of Brazil nuts in influencing selenium status and improving antioxidant defenses through GPx, but no significant effects on blood lipid profile or any other investigated outcome were found. Similarly, no significant results from that meta-analysis were found when considering blood lipid levels, including results for total cholesterol, HDL cholesterol, and LDL cholesterol.

In contrast, a small crossover study reported more favorable findings: ten healthy subjects were tested 4 times in a randomized crossover design in relation to the ingestion of different serving sizes of Brazil nuts: 0, 5, 20, or 50 g. Blood was drawn at multiple time points. A significant increase in plasma selenium levels was observed at 6 hours in groups receiving nuts. Serum LDL-c was significantly lower, whereas HDL-c was significantly higher 9 hours after the ingestion of 20 or 50 g of nuts.

In a pediatric population, a randomized controlled trial in obese female adolescents found that Brazil nut intake increased selenium levels, increased red blood cell velocity (a microvascular function measure), and reduced total cholesterol and LDL-cholesterol at the end of the intervention. Compared to placebo, Brazil nut intake reduced total cholesterol, triglycerides, and oxidized LDL, and increased red blood cell velocity. The authors concluded that Brazil nut intake improved the lipid profile and microvascular function in obese adolescents, possibly due to its high level of unsaturated fatty acids and bioactive substances.

A separate study in normolipidemic subjects found that Brazil nut ingestion did not alter HDL, LDL cholesterol, triacylglycerols, apolipoprotein A-I, or apolipoprotein B concentrations. HDL particle diameter and the activity of antioxidative paraoxonase 1 were also unaffected. However, consumption of Brazil nuts for a short duration by normolipidemic subjects, in comparable amounts to those tested for other nuts, did not alter serum lipid profile. Further studies are needed to elucidate the effect of Brazil nuts on blood lipid profile, preferably controlling for other biomarkers.

5.3 Thyroid Function

Evidence strength: Preliminary, based on small trials and mechanistic plausibility.

Selenium participates in several enzymatic reactions necessary for regulating the homeostasis of thyroid hormones. A 90-day double-blind RCT investigated this directly: seventy-seven dyslipidemic and hypertensive patients already receiving lipid-lowering drugs received either a dietary treatment associated with partially defatted Brazil nut flour (13 g/day providing 227.5 μg of selenium/day) or a placebo (dyed cassava flour). All patients received a personalized dietary guideline for dyslipidemia and hypertension and were followed for 90 days. Subjects undergoing hemodialysis benefited greatly from Brazil nut consumption, with improvements in lipid profile markers, oxidative stress, inflammation, and thyroid function.

No adverse effects were noted in small selenium trials, and routine selenium supplementation in patients with Hashimoto thyroiditis has been discussed as a promising adjuvant treatment option. However, the evidence specifically for Brazil nuts in thyroid disease remains limited, with most data extrapolated from selenium supplementation trials rather than Brazil nut–specific interventions.

5.4 Cognitive Function

Evidence strength: Preliminary, based on a single small pilot RCT.

Older adults with mild cognitive impairment were found to improve verbal fluency and constructional praxis in one clinical trial, though controversial results regarding the change in a marker of lipid peroxidation were observed in subjects with coronary artery disease. This refers to a pilot RCT by Cardoso et al. (2016) — Effects of Brazil nut consumption on selenium status and cognitive performance in older adults with mild cognitive impairment: a randomized controlled pilot trial, published in European Journal of Nutrition 2016;55:107–116. Researchers observed improvements in verbal fluency (p = 0.007) and constructional praxis (p = 0.031), with concurrent increases in blood selenium levels and erythrocyte glutathione peroxidase activity.

In the broader context of nut consumption and cognition, results from clinical trials investigating the effect of nut consumption on cognition are conflicting. Among five RCTs assessing cognition scores in one systematic review, two studies revealed a significant beneficial effect of nuts on cognition status. The evidence base for Brazil nuts specifically is very limited and awaits confirmation in larger trials.

5.5 Oxidative Stress and Inflammation

Evidence strength: Moderate for antioxidant biomarkers; more limited for inflammatory markers.

Improvement in antioxidant status through increased levels of selenium and/or glutathione peroxidase activity in plasma, serum, whole blood, and/or erythrocytes was observed in all studies that evaluated antioxidant status, regardless of the health state of the participants. In addition, healthy subjects improved lipid markers and fasting glucose; subjects with obesity had improvement in markers of lipid metabolism; and subjects with type 2 diabetes mellitus or dyslipidemia improved oxidative stress or DNA damage.

5.6 Hemodialysis / Chronic Kidney Disease

Evidence strength: Preliminary, small trials.

Different trials in the literature demonstrate positive outcomes such as modulation of the lipid serum profile, enhancement of the antioxidant system, and improvement of anti-inflammatory response. These effects have been assessed under different conditions, including cognitive impairment, dyslipidemia, cancer, and renal failure. Specific to hemodialysis, studies have used one Brazil nut daily for 3 months as the supplementation protocol (based on European Best Practice Guidelines suggesting 3–6 months of selenium supplementation for appropriate levels), and subjects undergoing hemodialysis benefited greatly from Brazil nut consumption, improving lipid profile markers, oxidative stress, inflammation, and thyroid function.

5.7 Cancer Prevention

Evidence strength: Very preliminary; largely animal/in vitro data; limited human biomarker evidence.

Dietary selenium, including from Brazil nuts, has been associated with protection against tumor development in laboratory animal studies. Higher levels of selenium intake in the range of 200–300 μg/day are believed to be effective in the prevention of certain types of cancer such as lung, colon, and prostate. However, these associations are based largely on population selenium levels and selenium supplementation trials rather than Brazil nut–specific intervention data. A colorectal cancer biomarker trial combining Brazil nuts with green tea extract has been referenced in the systematic review literature, but large-scale evidence is lacking. Selenium, in addition to some organic micronutrients like phytosterols, flavonoids, and polyphenols, is known to have healthy effects due to antioxidant and anticarcinogenic properties.

One risk consideration: in a risk/benefit analysis, including Brazil nuts and pistachios in nut mixtures resulted in aflatoxin B1 exposure of 2.3–2.8 ng/kg body weight per day, which may correspond to a small number of additional liver cancer cases annually in a modeled Swedish population. This must be weighed against cardiovascular benefits.

6. Body Systems and Health Areas

Endocrine system (thyroid): Selenium is essential for thyroid hormone homeostasis, particularly for thyroxine-to-triiodothyronine conversion via selenoprotein deiodinases.
Cardiovascular system: Brazil nuts may protect LDL from peroxidation and improve endothelial function, blood pressure, and lipid metabolism, and decrease endothelial inflammatory markers.
Antioxidant/immune system: Selenium is necessary for the functioning of glutathione peroxidase (GPx), which catalyzes hydrogen peroxide and lipid hydroperoxide through glutathione metabolism.
Neurological/cognitive: Selenium deficiency has been linked to cognitive decline; one pilot RCT demonstrated improvements in verbal fluency and constructional praxis in older adults with mild cognitive impairment.
Renal system: Clinical evidence in hemodialysis patients suggests improvements in selenium status, antioxidant capacity, lipid profile, and inflammatory markers.
Metabolic health: Healthy subjects improved lipid markers and fasting glucose, and subjects with obesity had improvement in markers of lipid metabolism.

7. Dosages Reported in Clinical Studies

The following dosages are reported directly from published studies and trials, and are not recommendations:

2 Brazil nuts per day (approximately 100 μg Se targeted; actual mean intake 53 μg Se/d), consumed for 12 weeks in a randomized controlled trial in 59 New Zealand adults.
1 Brazil nut per day for 8 weeks (followed by 8 weeks of washout) in a 4-month interventional trial — the SU.BRA.NUT study — in healthy volunteers of both genders at the University of São Paulo.
13 g/day of partially defatted Brazil nut flour (providing 227.5 μg of selenium/day) for 90 days in a randomized placebo-controlled double-blind trial in dyslipidemic and hypertensive patients.
0, 5, 20, or 50 g of Brazil nuts were tested as single servings in a randomized crossover study in 10 healthy subjects.
One nut daily for 3 months was used in hemodialysis patient supplementation studies, based on European Best Practice Guidelines suggesting 3 to 6 months of selenium supplementation.

8. Safety Considerations and Interactions

Selenium Toxicity (Selenosis)

Despite its importance to human metabolism, selenium can become toxic above a certain threshold due to its interference with sulfur metabolism. There is a narrow window between selenium deficiency, adequacy, and toxicity. The tolerable selenium intake limit is considered 400 μg Se/day, while the intake associated with toxicity (selenosis) was estimated to be around 1,200 μg Se/day (in people exposed to large amounts of organic selenium in China).

The recommended dietary allowance for adults is about 55–70 μg/day, and the tolerable upper intake level to prevent harmful effects, as recommended by the European Food Safety Authority (EFSA), is 255 μg/day.

Consumption of one seed (5 g) from a high-selenium area meets the recommended daily allowance; the recommended serving size of 30 g may exceed the allowable daily intake (400 μg) or even the toxicity threshold (1,200 μg).

Chronic selenosis symptoms range from fragile or depigmented hair and nails to loss of these tissues; characteristic acute selenosis symptoms include diarrhea, nausea, skin rash, disorders of the nervous system, fatigue, and irritability. Excess selenium intake can also lead to hair loss, broken and sloughing nails, and even cardiovascular pathology, endocrine dysfunction, and cancer.

There are also possible risks of supra-nutritional selenium levels, as suggested by several recent papers on the complex U-shaped relationship between selenium dose and diseases such as type 2 diabetes or cancers.

High Variability of Selenium Content

The average selenium concentrations and ranges from two growing regions (Acre-Rondônia and Manaus-Belém) were, respectively, 3.06 ± 4.01 ppm (range 0.03–31.7) and 36.0 ± 50.0 ppm (range 1.25–512.0), demonstrating extraordinary variability even within regions. Due to the large variation of selenium in Brazil nuts, it is difficult to determine whether Brazil nuts are providing inadequate, adequate, or excessive intake.

Barium Content

Brazil nuts are often recommended for their high selenium content but have also been reported to contain elevated levels of barium, a potentially toxic element. Regular daily consumption of Brazil nuts may exceed the currently suggested tolerable daily intake (TDI) for barium (approximately 0.2 mg/kg body weight/day). However, barium exhibits low bioaccessibility (approximately 2%), substantially reducing the effective exposure from dietary intake.

Radioactive Radium

Brazil nuts stand out from other nuts in terms of their high (albeit highly variable) radium content. The radium isotopes Ra-226 and Ra-228 emit alpha- and beta-radiation, a type of radiation particularly harmful when ingested. A published overview of radium levels in Brazil nuts suggests that consuming one Brazil nut daily is generally safe for adults.

Aflatoxin Contamination

Nuts may be a major source of aflatoxin B1, a potent liver carcinogen. Brazil nuts in particular are susceptible to mold contamination under improper storage conditions. In modeling scenarios, including Brazil nuts in nut consumption resulted in aflatoxin B1 exposure of 2.3–2.8 ng/kg body weight per day, which may correspond to a small number of additional liver cancer cases in population-level analyses. This risk is substantially reduced by proper storage, prompt consumption after purchase, and regulated commercial monitoring.

Inflammatory Effects at High Selenium Levels

One randomized controlled trial found that consumption of Brazil nuts with high selenium levels increased inflammation biomarkers in obese women. This underscores the importance of selenium content at the time of consumption, and that effects may differ depending on the baseline selenium status and selenium concentration of the specific nuts consumed.

Context of Safe Intake

While healthy, Brazil nuts should be consumed in moderation. Consumption of one seed (5 g) from a high-selenium area meets the recommended daily allowance; the recommended serving size of 30 g may exceed the allowable daily intake (400 μg). Researchers have suggested that the recommended serving size may need re-evaluation, that consumers should be warned not to exceed the serving size, and that the seed may be sold as part of mixed nuts to avoid excess selenium intake.

References

Health Conditions

Health conditions that Brazil nut may help support.

No conditions available.

Body Systems

Body systems that Brazil nut may help support.

No body systems available.