Laboratory / cell studyindependent cross-checkabstract checked I-FRU-114 standard review
Antioxidants in apple peels
Antioxidant activity of apple peels.
Overview
Wolfe K et al.. J Agric Food Chem 2003 · PMID 12537430 · DOI 10.1021/jf020782a
Apple peels contain more phenolic compounds and antioxidant activity than the flesh.
Does the study support the specific claim? No · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Compare peel and flesh.
- How was the study done?
Lab analysis.
- How many people, animals or samples were studied?
4 apple varieties.
- What was actually found?
Peel richest in phenolics.
- How large was the observed effect?
e.g. 588.9 mg/100 g.
- What do the results mean in everyday life?
Peeling discards some plant compounds.
- What are the study's limitations?
Lab only.
- What does it say about Elawady's specific claim?
Limits C-FRU-04.
- Do the results apply to Germany and Europe?
Applicable.
- What can explicitly not be concluded from this study?
It does not show health effects in people.
Scientific in-depth review
1. Full reference
- Authors
- Wolfe K et al.
- Journal
- J Agric Food Chem
- Year
- 2003
- Identifier
- PMID 12537430 DOI 10.1021/jf020782a
- Verification
- verified – PubMed efetch 2026-10-26 + Crossref works API
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
Not stated in abstract.
2. Research question
How do phytochemical content and antioxidant activity of apple peels compare with flesh?
3. Study design and population
- Study design
- Laboratory / cell study – Laboratory analysis of apple components
- Population
Four apple varieties (New York State)
- Country
USA
- Period
Not stated
- Sample size
4 varieties
- Inclusion and exclusion criteria
Not applicable
4. Methods and endpoints
- Exposure / intervention
Peel vs flesh vs flesh+peel
- Comparator
Flesh
- Endpoints
Phenolics, flavonoids, antioxidant and antiproliferative activity
- Statistical methods
Mean +/- SD comparisons
5. Actual results
- Results
Total phenolics and flavonoids highest in peels (e.g. Idared 588.9 mg GAE/100 g); peels had significantly higher antioxidant activity than flesh; peels inhibited HepG2 cancer cell proliferation more effectively.
- Absolute risks
Not applicable
- Authors' conclusion
Apple peels are a valuable source of antioxidants and may impart health benefits.
6. Strengths
- Direct peel vs flesh comparison
7. Weaknesses
- In vitro; no human outcomes
- Abstract only
8. Risk of bias
- Orienting tool
- none applicable
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Laboratory study.
9. Assessment of the statistical interpretation
Not applicable.
10. Relevance to the specific claim
Peeling removes the most phenolic-rich part of the apple (limits C-FRU-04), though health relevance is unproven.
11. Independent contrary findings
12. Transferability to Germany and Europe
Applicable.
13. Overall methodological judgement
Indirect argument against routine peeling.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | some concerns |
| Precision of results | not applicable |
| Directness | very indirect |
| Reproducibility | replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Human relevance.
15. Linked fact checks
- Apples and pears should be eaten only peeled. – Studies contradicting or limiting the claim