Almonds and oxidative stress markers in adults
What it found
In adults, almond supplements at doses above 60 g/day lowered some markers of oxidative stress and raised one antioxidant enzyme.
Lower doses did not show the same changes.
What they found
Studies in people
MDA and dose
Overall, almonds did not change MDA, a marker of fat damage. But when the dose was above 60 g/day, MDA fell significantly. Doses below 60 g/day showed no effect.
DNA damage marker
Almond supplementation significantly reduced 8-OHdG, a marker of oxidative DNA damage.
Uric acid
Almond supplementation significantly lowered uric acid levels.
SOD enzyme
Almond supplementation significantly increased SOD, an antioxidant enzyme. When split by dose, neither the lower nor the higher dose group showed a significant change on its own.
GPx enzyme
Almond supplementation had no significant effect on GPx, another antioxidant enzyme.
Other findings
Variability between studies
The studies varied a lot in their results for SOD and GPx. Differences in study design, dose, population, and how almonds were prepared may explain this.
What the authors conclude
“This meta-analysis shows that almond supplementation, particularly at doses > 60 g/day, reduces oxidative DNA damage (e.g., 8-OHdG), lipid peroxidation (e.g., MDA), and UA levels while enhancing SOD activity, suggesting its potential as a functional food for oxidative stress management.”
Also in their conclusions
- They conclude that almond supplementation, particularly at doses above 60 g/day, reduces oxidative DNA damage, lipid peroxidation, and uric acid levels while enhancing SOD activity.
- They say the findings suggest almonds' potential as a functional food for oxidative stress management.
- They call for standardized dosing and biomarker assessment in future trials to optimize benefits, especially for high-risk groups like smokers or people with chronic diseases.
How it was done
The authors wanted to pool the evidence on whether almonds affect oxidative stress, because individual studies had shown antioxidant potential but the overall picture was unclear.
They pooled eight randomised and crossover trials with 424 adults, including healthy people, overweight or obese adults, smokers, and patients with conditions such as coronary artery disease and high blood lipids. Almond doses ranged from 5 g/day to 168 g/day, and studies lasted 4 to 24 weeks.
What it can’t tell you
- The studies varied widely in dose, duration, population, and almond form, so the pooled results cannot pinpoint the best dose or duration.
- Most included studies were small, and some had unclear or high risk of bias, which limits confidence in the findings.
- The review cannot show whether these changes in oxidative stress markers lead to better health outcomes.
Who paid
- Conflicts
- Declarations. Competing interests: The authors declare no competing interests.
- Authors work at
- Tehran University of Medical Sciences, Iran; Islamic Azad University, Iran; Tabriz University of Medical Sciences, Iran
The paper
- Title
- The impact of almond supplementation on oxidative stress biomarkers: a systematic review and meta-analysis of randomized control trials
- Type
- Systematic review and meta-analysisThe authors follow a set, published method to find every relevant study, then combine the numbers from them into one result.
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Kolahi A, Movahed S, Tejareh F, Saeedy SAG, Gholizadeh M (2025). The impact of almond supplementation on oxidative stress biomarkers: a systematic review and meta-analysis of randomized control trials. Scientific reports. doi:10.1038/s41598-025-14701-wFree full textPubMed 40804320DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error