Cohort studyindependent cross-checkfull text checked I-UPF-109 in-depth review
Ultra-processed food and depression in US nurses
Consumption of Ultraprocessed Food and Risk of Depression.
Overview
Samuthpongtorn C et al.. JAMA Netw Open 2023 · PMID 37728928 · DOI 10.1001/jamanetworkopen.2023.34770
Women eating the most ultra-processed food had about 50% more new depression; the link was mainly with artificial sweeteners.
Does the study support the specific claim? Partly · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
To test UPF and later depression.
- How was the study done?
Cohort study with repeated diet surveys.
- How many people, animals or samples were studied?
31,712 middle-aged women.
- What was actually found?
More depression with high UPF, especially sweetened drinks.
- How large was the observed effect?
HR 1.49 (1.26-1.76).
- What do the results mean in everyday life?
Diet and mood may be linked; cause is unclear.
- What are the study's limitations?
Observational; self-reported diagnosis.
- What does it say about Elawady's specific claim?
Supports the association in C-UPF-04.
- Do the results apply to Germany and Europe?
Moderate.
- What can explicitly not be concluded from this study?
Cannot prove UPF causes depression.
Scientific in-depth review
1. Full reference
- Authors
- Samuthpongtorn C et al.
- Journal
- JAMA Netw Open
- Year
- 2023
- Identifier
- PMID 37728928 DOI 10.1001/jamanetworkopen.2023.34770 · PMC10512104
- Verification
- verified – PubMed efetch 2026-10-26; Crossref works API 2026-10-26
- Retracted
- no
- Corrections
ErratumIn: JAMA Netw Open. 2023 Oct 2;6(10):e2341346. doi: 10.1001/jamanetworkopen.2023.41346. (erratum notice; no retraction)
- Extent checked
- full text
- Conflicts of interest and funding
No COI statement in PubMed record; funding listed: NCI NIH HHS, NIA NIH HHS, NIDDK NIH HHS, NINR NIH HHS
2. Research question
Is UPF consumption associated with incident depression?
3. Study design and population
- Study design
- Cohort study – Prospective cohort study (Nurses' Health Study II); research letter
- Population
Middle-aged US women free of depression at baseline (95% non-Hispanic white)
- Country
USA
- Period
2003-2017
- Sample size
31,712 women in Results (the article's one-line abstract gives 31,172; an erratum was issued, content not checked); 2,122 strict and 4,840 broad depression cases
- Inclusion and exclusion criteria
Free of depression at baseline
4. Methods and endpoints
- Exposure / intervention
UPF intake (Nova) by FFQ every 4 years
- Comparator
Lowest quintile (<4 servings/day)
- Endpoints
Depression (strict: clinician diagnosis and antidepressant use; broad: either)
- Statistical methods
Cox models adjusted for BMI, activity, smoking, comorbidities, income, social network, sleep, pain etc.; 4-year lag analysis
5. Actual results
- Results
Highest vs lowest quintile (>8.8 vs <4 servings/day): strict definition HR 1.49 (1.26-1.76); broad definition HR 1.34 (1.20-1.50); robust to diet-quality adjustment; 4-year lag HR 1.32 (1.13-1.54). Among components only artificially sweetened beverages (HR 1.37, 1.19-1.57) and artificial sweeteners (1.26, 1.10-1.43) were associated. Reducing UPF by >=3 servings/day associated with lower risk (HR 0.84, 0.71-0.99).
- Absolute risks
Strict definition crude rates 4.08 vs 6.11 per 1,000 person-years (Q1 vs Q5; stats/C-UPF-04_samuthpongtorn.py)
- Authors' conclusion
Greater UPF intake, particularly artificial sweeteners and artificially sweetened beverages, is associated with increased risk of depression.
6. Strengths
- Prospective with repeated diet measures
- Lag analysis addresses reverse causation
- Full text read
7. Weaknesses
- Self-reported diagnosis; misclassification possible
- Mostly white women
- Erratum issued (JAMA Netw Open 2023;6(10):e2341346)
- Broad-definition case counts in the table appear duplicated from the strict definition
8. Risk of bias
- Orienting tool
- ROBINS-E
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Observational; outcome misclassification possible.
9. Assessment of the statistical interpretation
Crude rate ratio (1.50) matches adjusted HR (1.49); signal concentrated in sweetener components.
10. Relevance to the specific claim
Adds prospective evidence with a lag analysis for UPF and depression.
11. Independent contrary findings
Association driven by artificial sweeteners rather than UPF broadly; residual confounding.
12. Transferability to Germany and Europe
Moderate.
13. Overall methodological judgement
Supports an association; does not establish causation.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | some concerns |
| Precision of results | moderate |
| Directness | direct |
| Reproducibility | partly replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | moderate |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Mechanism; replication in men and other populations.
15. Linked fact checks
- Ultra-processed foods increase the risk of depression and common mental disorders. – Studies supporting the claim