Cross-sectional studyindependent cross-checkfull text checked I-EGG-13 in-depth review
Food sensitivities and nightmares
More dreams of the rarebit fiend: food sensitivity and dietary correlates of sleep and dreaming.
Overview
Nielsen T et al.. Front Psychol 2025 · PMID 40667395 · DOI 10.3389/fpsyg.2025.1544475
Only 5.5% of students thought food affected their dreams, mostly sweets and dairy; eggs were rarely named. People with food allergy or lactose intolerance reported more nightmares.
Does the study support the specific claim? No · Methodological quality: low
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Why do people perceive that food affects dreams?
- How was the study done?
Online survey
- How many people, animals or samples were studied?
1,082; Online participants
- What was actually found?
5.5% (59/1,076) reported food affected dreams; sweets (30%) and dairy (21%) were blamed most, meat 8%, eggs 2% (3 mentions, none for disturbing dreams). Food allergy and lactose intolerance were linked with higher nightmare scores, the latter partly via gut symptoms.
- How large was the observed effect?
Associations; mediation
- What do the results mean in everyday life?
Digestive discomfort may disturb sleep.
- What are the study's limitations?
Students given course credit; everything self-reported; only 59 people perceived food effects; cross-sectional; many tests
- What does it say about Elawady's specific claim?
Partly supports individual food-sensitivity effects on dreams; does not support a general effect of eggs or chicken (eggs rarely named, chicken not separated).
- Do the results apply to Germany and Europe?
Moderate.
- What can explicitly not be concluded from this study?
Cannot show causation, and says nothing about snoring, sinusitis or headaches.
Scientific in-depth review
1. Full reference
- Authors
- Nielsen T et al.
- Journal
- Front Psychol
- Year
- 2025
- Identifier
- PMID 40667395 DOI 10.3389/fpsyg.2025.1544475
- Verification
- verified – PubMed efetch 2026-10-25
- Retracted
- no
- Corrections
- none
- Extent checked
- full text
- Conflicts of interest and funding
Authors declare no commercial or financial conflicts; author(s) were Frontiers editorial board members. Funding source not stated in the available full text (author contributions list 'funding acquisition').
2. Research question
Why do people perceive that food affects dreams?
3. Study design and population
- Study design
- Cross-sectional study – Cross-sectional online survey (Qualtrics) of undergraduate psychology students
- Population
Undergraduate psychology students at MacEwan University, Canada (mean age 20.3 +/- 3.68, range 17-54; 721 women, 338 men, 23 other/undisclosed; 46.4% White, 22.2% Asian, 7.9% Black, 6.3% Arab); course credit (2% of final grade)
- Country
Canada (MacEwan University, Edmonton)
- Period
January-April 2023
- Sample size
1,082 (59/1,076 FDD+; food-category choices from FDD+ participants: 131)
- Inclusion and exclusion criteria
Psychology students who completed the survey; no clinical exclusions; items could be left blank
4. Methods and endpoints
- Exposure / intervention
Self-reported food sensitivities (food allergy, lactose intolerance, gluten intolerance), diet and eating behaviour, evening eating, GI symptoms, perceived food effects
- Comparator
FDD+ vs FDD-; with vs without each food sensitivity
- Endpoints
Perceived food effects on sleep/dreams; dream recall, dream emotional tone, nightmare frequency, Nightmare Disorder Index (NDI); PSQI-M
- Statistical methods
Chi-square, t-tests, linear regression with gender as covariate, Spearman correlations, SEM-based mediation (GI symptoms); alpha 0.05, no multiplicity correction
5. Actual results
- Results
40.2% reported food affected sleep (worse 24.7%, better 20.1%); 59/1,076 (5.5%) reported food or late eating affected dreams (FDD+). FDD+ had higher NDI (3.61 +/- 3.18 vs 2.43 +/- 3.03; p=0.004). Of 131 food choices by FDD+ participants: desserts/sweets 29.8%, dairy 20.6%, fruit 9.2%, meat (excluding seafood) 8.4%, cereals 6.1%, eggs 2.3% (3 choices, none for disturbing or bizarre dreams); disturbing dreams blamed on sweets 31%, dairy 22%, meat 16%, spicy 13%. FDD+ more often had food allergy (18.6% vs 9.3%; p=0.039) and gluten intolerance; lactose intolerance associated with higher NDI (p<0.001), partly mediated by GI symptom severity; food allergy also associated with higher NDI (p=0.012).
- Absolute risks
not applicable
- Authors' conclusion
Food-dependent dreaming predicts nightmare frequency and severity, with dairy and sweets most commonly blamed; food sensitivities, particularly lactose intolerance, are associated with nightmares, often mediated by GI symptoms; experimental studies needed. Causal direction unresolved.
6. Strengths
- Large sample (1,082)
- Standard scales (PSQI, Nightmare Disorder Index) plus targeted probes
- Pre-specified hypotheses from earlier study; mediation analysis
- Authors discuss causal direction and misattribution
7. Weaknesses
- Student convenience sample with course credit
- All exposures and outcomes self-reported; food sensitivities not clinically verified
- Only 59 FDD+ participants; food-category shares based on 131 choices
- Cross-sectional: reverse causation and shared-method bias
- Many tests without multiplicity correction
- Cultural beliefs not assessed (authors' stated limitation)
- No snoring, sinusitis or headache outcomes; chicken not separated from 'meat'
8. Risk of bias
- Orienting tool
- No standard tool fits (descriptive cross-sectional survey); structured validity judgement following ROBINS-E domains where applicable
- Type of assessment
- structured assessment based on the full text by a single reviewer (no formal double review)
- Full formal assessment
- no
- Overall risk of bias
- high
- Rationale
Single-reviewer structured judgement based on the full text; not a formal assessment (needs two independent reviewers and a protocol).
| Domain | Judgement | Rationale |
|---|---|---|
| Confounding | high | Adjustment only for gender; psychological distress, sleep disorders and other factors may drive both perceived food sensitivities and nightmares. |
| Exposure measurement | high | Self-reported, unverified food allergy/intolerance and perceived food effects. |
| Selection of participants | high | Psychology students at one university receiving course credit. |
| Missing data | low | Small item non-response (e.g. 1,076/1,082 for FDD item). |
| Outcome measurement | some concerns | Validated NDI and PSQI-M but self-reported and same-source as exposure. |
| Selection of reported result | some concerns | Many comparisons, no correction; hypotheses stated in advance from the 2015 study. |
Full-text review (25 October 2026): Added population details (MacEwan University students, Jan-Apr 2023), eggs named in only 3/131 food choices (none for disturbing dreams) and chicken not separated, exact NDI/food-allergy statistics; funding not stated; directness downgraded to very_indirect; structured validity domains (overall unchanged: high).
9. Assessment of the statistical interpretation
Associations only.
10. Relevance to the specific claim
11. Independent contrary findings
Not applicable.
12. Transferability to Germany and Europe
Moderate.
13. Overall methodological judgement
Survey shows that a small minority (5.5%) perceive food effects on dreams, mostly sweets and dairy; eggs were rarely named (2.3% of choices, none for disturbing dreams) and chicken was not reported separately. Supports individual food-sensitivity (especially lactose intolerance) links with nightmares as associations, not general egg/chicken effects.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | low |
| Risk of bias | high |
| Precision of results | low |
| Directness | very indirect |
| Reproducibility | partly replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | moderate |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Experimental food-challenge studies; clinically verified sensitivities; whether egg allergy specifically relates to sleep or dreams.
15. Linked fact checks
- Eating eggs causes snoring, sinusitis and nightmares in (practically) everyone who eats them, and stopping eggs and chicken relieves headaches. – Studies contradicting or limiting the claim
- Eating chicken causes nightmares, panic attacks, hallucinations and psychological harm in children and adults; panic attacks became widespread in the last 20 years because of mass chicken production. – Studies contradicting or limiting the claim