Guideline / position statementindependent cross-checkabstract checked★ key study I-FAST-124 standard review
EU reference values for water
Scientific Opinion on Dietary Reference Values for water.
Overview
EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA). EFSA Journal 2010 · DOI 10.2903/j.efsa.2010.1459
European experts set adequate total water intake at 2.0 L/day for women and 2.5 L/day for men, including water in food.
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?
Set reference values for water.
- How was the study done?
Expert review of intake and urine data.
- How many people, animals or samples were studied?
not applicable
- What was actually found?
AIs by age and sex.
- How large was the observed effect?
not applicable
- What do the results mean in everyday life?
Normal water needs are substantial; heat increases them.
- What are the study's limitations?
Only for moderate climate and activity.
- What does it say about Elawady's specific claim?
Contradicts water restriction; neutral on thirst-guided drinking.
- Do the results apply to Germany and Europe?
EU reference; Egypt's hotter climate implies higher needs.
- What can explicitly not be concluded from this study?
Needs in hot climates.
Scientific in-depth review
1. Full reference
- Authors
- EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA)
- Journal
- EFSA Journal
- Year
- 2010
- Identifier
- DOI 10.2903/j.efsa.2010.1459
- Verification
- verified – Crossref record and OpenAlex abstract fetched 2026-10-26 (EFSA/Wiley page returned 403)
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
not stated in abstract
2. Research question
What are adequate intakes of total water by age group?
3. Study design and population
- Study design
- Guideline / position statement – Agency scientific opinion setting adequate intakes
- Population
EU population by age group
- Country
European Union
- Period
not stated in abstract
- Sample size
not applicable
- Inclusion and exclusion criteria
not stated in abstract
4. Methods and endpoints
- Exposure / intervention
Total water intake (drinks plus food moisture)
- Comparator
not applicable
- Endpoints
Adequate intakes (AI)
- Statistical methods
not applicable
5. Actual results
- Results
AIs for total water (drinks and food moisture), valid for moderate environmental temperature and moderate activity (PAL 1.6): adults 2.0 L/day women, 2.5 L/day men; same for elderly; children 2-3 y 1.3 L, 4-8 y 1.6 L, boys 9-13 y 2.1 L, girls 9-13 y 1.9 L; pregnancy +300 mL/day; lactation about +700 mL/day.
- Absolute risks
not reported
- Authors' conclusion
Adequate intakes derived from observed intakes with desirable urine osmolarity.
6. Strengths
- Official EU reference values
7. Weaknesses
- AIs, not requirements; based on observed intakes
- Only moderate temperatures covered
8. Risk of bias
- Orienting tool
- none applicable
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- not assessable
- Rationale
Agency opinion.
9. Assessment of the statistical interpretation
Not applicable.
10. Relevance to the specific claim
Total water need of adults is about 2-2.5 L/day including food moisture under moderate conditions, more in heat, pregnancy and lactation; incompatible with deliberate water restriction and multi-day dry fasting.
11. Independent contrary findings
12. Transferability to Germany and Europe
Universal biology; applies in Europe and Egypt.
13. Overall methodological judgement
Official reference values; they do not mandate drinking beyond thirst but define the normal total intake.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | not assessable |
| Precision of results | not applicable |
| Directness | direct |
| Reproducibility | not replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | moderate |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
15. Linked fact checks
- Drink water only when thirsty; there is no need to force a fixed daily amount. – Studies with mixed or unclear results
- Do not drink much water because it distends the abdomen and raises abdominal pressure; even when thirsty during long fasting hours just wet the lips; fasting three days in a row each week without food and drink is not harsh. – Studies contradicting or limiting the claim