The Claim
Soil selenium concentrations in the Amazon region are below toxic thresholds, with maximum measured levels of 625.91 μg/kg, indicating that Brazil nut trees do not accumulate selenium to concentrations that result in toxic levels in their nuts under natural environmental conditions.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
Brazil nuts grown in the Amazon do not contain dangerous levels of selenium because the soil in that region has selenium concentrations below toxic limits, with the highest recorded level being 625.91 μg/kg.
See the scientific wording
Soil selenium levels in the Amazon region are below toxic thresholds, with maximum concentrations of 625.91 μg/kg, suggesting that Brazil nut trees do not accumulate selenium to levels that would render the nuts toxic under natural conditions.
Brazil nut trees absorb selenium from the soil through their roots, but they do not move all of it into the nuts. The trees hold back most of the selenium in their roots and wood, so the nuts only get a limited amount, even when the soil has a lot of selenium.
What the research says
1 studyStudy: Natural variation of selenium in Brazil nuts and soils from the Amazon region.
Even in places where the soil has the most selenium, the nuts that grow there aren't poisonous — they just have a lot more of this important nutrient, sometimes enough for days of your daily need in one nut.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.