Systematic reviewindependent cross-checkabstract checked I-WHT-109 standard review
Across many reviews, refined grains were not clearly linked to death risk
Umbrella Review of Systematic Reviews and Meta-analyses on Consumption of Different Food Groups and Risk of All-cause Mortality.
Overview
Onni AT et al.. Adv Nutr 2025 · PMID 39956388 · DOI 10.1016/j.advnut.2025.100393
An umbrella review of 41 meta-analyses found lower mortality with whole grains but no clear association for refined grains.
Does the study support the specific claim? Partly · Methodological quality: high
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Summarise food groups and mortality.
- How was the study done?
Umbrella review.
- How many people, animals or samples were studied?
41 meta-analyses.
- What was actually found?
Whole grains beneficial; refined neutral.
- How large was the observed effect?
Not quantified in abstract.
- What do the results mean in everyday life?
Whole grains are the better choice; white bread not proven deadly.
- What are the study's limitations?
Overlap.
- What does it say about Elawady's specific claim?
Weakens the refined-harm claim.
- Do the results apply to Germany and Europe?
Moderate-high.
- What can explicitly not be concluded from this study?
Cannot prove causation.
Scientific in-depth review
1. Full reference
- Authors
- Onni AT et al.
- Journal
- Adv Nutr
- Year
- 2025
- Identifier
- PMID 39956388 DOI 10.1016/j.advnut.2025.100393 · PMC11931306
- Verification
- verified – PubMed efetch 2026-10-26; Crossref works API 2026-10-26
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
Authors report no conflicts.
2. Research question
How are food groups associated with all-cause mortality?
3. Study design and population
- Study design
- Systematic review – Umbrella review of systematic reviews and meta-analyses (AMSTAR 2)
- Population
Adults
- Country
International
- Period
Registered PROSPERO CRD42024498035
- Sample size
41 meta-analyses (18 high, 8 moderate, 5 low, 10 critically low quality)
- Inclusion and exclusion criteria
Systematic reviews with meta-analysis of food groups and all-cause mortality
4. Methods and endpoints
- Exposure / intervention
Food groups incl. refined and whole grains
- Comparator
Low intake
- Endpoints
All-cause mortality
- Statistical methods
Umbrella synthesis; AMSTAR 2
5. Actual results
- Results
Higher intake of nuts, whole grains, fruits, vegetables and fish associated with lower mortality; red and processed meat and sugar-sweetened beverages with higher mortality; dairy and refined grains did not show clear associations with mortality.
- Absolute risks
not reported
- Authors' conclusion
Refined grains showed no clear association with all-cause mortality.
6. Strengths
- Registered protocol
- AMSTAR 2 grading
7. Weaknesses
- Overlapping meta-analyses
- Observational base
8. Risk of bias
- Orienting tool
- AMSTAR 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- low
- Rationale
Umbrella review with quality grading.
9. Assessment of the statistical interpretation
Qualitative summary in abstract; no pooled refined-grain estimate reported in the abstract.
10. Relevance to the specific claim
Overall literature: no clear mortality association for refined grains; clear inverse for whole grains.
11. Independent contrary findings
PURE extreme-intake signal.
12. Transferability to Germany and Europe
Moderate-high.
13. Overall methodological judgement
High-level synthesis; overlaps with other meta-analyses.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | high |
| Risk of bias | low |
| Precision of results | not applicable |
| Directness | direct |
| Reproducibility | replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | moderate |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
None.
15. Linked fact checks
- Heavy intake of refined grains (white bread etc.) is associated in the largest population studies with higher mortality and major cardiovascular disease (archive: PURE, +27% mortality, +33% major cardiovascular events at >=350 g/day). – Studies contradicting or limiting the claim
- Replacing refined grains with whole grains lowers all-cause mortality by 17% and coronary heart disease by 19%, while refined grains offer no protective benefit (archive interpretation of Aune 2016). – Studies supporting the claim