Barium levels in Brazil nuts worldwide
What it found
Across 24 published studies, Brazil nuts contained an average of about 1.27 mg/g of barium.
For most adults, one Brazil nut a day stays within suggested barium limits, but two a day may go over them in some regions and for people under 60 kg.
What they found
Studies in people
Barium in one person
In a 1980s mass balance study, one 68 kg man ate about 92 g of ground Brazil nuts containing about 179.2 mg of barium, roughly 13 times the suggested daily limit for his weight. About 90% of the barium was not recovered in his feces or urine over the following 6 days, and the authors concluded it was deposited in his tissues.
Trial in women
A randomised trial in Brazil gave 55 women with obesity one Brazil nut (about 5 g) a day for 8 weeks and found no change in barium levels in their blood plasma. However, those nuts contained only about 0.05 mg/g of barium, about 4% of the average found in this review, so the result may not apply to Brazil nuts generally.
Studies in people and animals
How much is absorbed
How much barium people absorb from Brazil nuts is not well known. Some barium in the nuts may be in a form that is poorly absorbed, but the low pH and high chloride in the stomach might increase absorption, and current knowledge remains very limited.
Other findings
Average barium level
The average barium level across the studies was 1.27 mg/g, with values ranging from 0.03 to 5.89 mg/g. Levels were slightly lower in nuts from Brazil and slightly higher in nuts from Europe.
Two nuts a day
For most regions, eating two Brazil nuts a day did not exceed the suggested barium limit for adults. But in Germany, Guyana and Japan, and for people weighing under 60 kg, two nuts a day could already go over the limit, before counting other foods.
Three nuts a day
For a 70 kg adult, three Brazil nuts a day would provide about 15 to 19 mg of barium, which exceeds the suggested daily limits. One nut a day would exceed the limits for children weighing about 25 to 32 kg or less.
What the authors conclude
- They conclude that a typical barium level in Brazil nuts of about 1.3 mg/g can be assumed, and that an average long-term intake of one Brazil nut daily by adults generally does not exceed current tolerable daily intakes and can therefore be considered safe.
- They advise that repeated assessments of locally purchased Brazil nuts are needed to develop more reliable and region-specific intake recommendations.
- They state that current evidence remains insufficient to draw firm conclusions about clinically relevant health effects of barium exposure from Brazil nut consumption, and that caution is warranted when evaluating the safety of Brazil nuts.
How it was done
Brazil nuts are often recommended for their selenium, but they also contain barium, a potentially toxic element. No global review of barium levels in Brazil nuts had been published, so it was unclear whether regular daily consumption could exceed suggested barium limits.
The authors searched three research databases for studies reporting barium levels in Brazil nuts, with no language or time limits, and found 24 eligible publications from 1933 to 2023. They pooled the reported levels and compared the barium from eating Brazil nuts against suggested tolerable daily intakes.
What it can’t tell you
- The barium limits used here come from studies in mice given barium in drinking water, so it is highly uncertain how well they apply to barium taken in from Brazil nuts by people.
- Most of the studies measured barium levels in nuts, not what happens in the body, so they cannot show whether regularly eating Brazil nuts affects health.
- The one trial in people used nuts with very low barium levels, so its results may not apply to Brazil nuts with the average or higher levels found in this review.
Who paid
- Conflicts
- The authors declare no conflicts of interest.
- Authors work at
- Medical Center - University of Freiburg, Germany; Research Institute for Plant-Based Nutrition (IFPE), Germany
The paper
- Title
- Barium Levels in Brazil Nuts: A Global Review of the Literature
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Licence
- CC BY. Words in quotation marks are the authors’; the rest is our summary.
- Cite
- Koeder C, Keller M (2025). Barium Levels in Brazil Nuts: A Global Review of the Literature. Journal of food science. doi:10.1111/1750-3841.70643Free full textPubMed 41169104DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error