Cohort studyindependent cross-checkabstract checked I-SUG-103 standard review
Too much sugar linked to earlier death
Association between added sugar intake and mortality is nonlinear and dependent on sugar source in 2 Swedish population-based prospective cohorts.
Overview
Ramne S et al.. Am J Clin Nutr 2019 · PMID 30590448 · DOI 10.1093/ajcn/nqy268
In two Swedish cohorts, people eating more than 20% of their calories as added sugar had about 30% higher mortality; the lowest risk was at 7.5-10%.
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?
Examine how sugar intake and sugar sources relate to death rates.
- How was the study done?
Followed about 48,700 Swedish adults for many years.
- How many people, animals or samples were studied?
Two Swedish population cohorts.
- What was actually found?
Very high sugar intake went with higher mortality; moderate intake had the lowest risk.
- How large was the observed effect?
+30% mortality at >20% of energy; +23% at <5% in one cohort.
- What do the results mean in everyday life?
Moderate sugar is not clearly harmful, but large amounts are linked to earlier death.
- What are the study's limitations?
Observational; low-intake finding may be due to other factors.
- What does it say about Elawady's specific claim?
Refutes 'any amount is beneficial' and 'a kilogram per day'.
- Do the results apply to Germany and Europe?
European data.
- What can explicitly not be concluded from this study?
Cannot prove that sugar itself causes the deaths.
Scientific in-depth review
1. Full reference
- Authors
- Ramne S et al.
- Journal
- Am J Clin Nutr
- Year
- 2019
- Identifier
- PMID 30590448 DOI 10.1093/ajcn/nqy268
- Verification
- verified – PubMed efetch 2026-10-26 + Crossref 2026-10-26
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
Not stated in abstract record
2. Research question
How are added and free sugar intake and specific sugar sources associated with mortality?
3. Study design and population
- Study design
- Cohort study – Two prospective population-based cohorts with Cox regression
- Population
Swedish adults (Malmö Diet and Cancer Study; Northern Swedish Health and Disease Study)
- Country
Sweden
- Period
Baseline 1990s; long follow-up
- Sample size
24,272 (MDCS) and 24,475 (NSHDS)
- Inclusion and exclusion criteria
Population-based cohorts; details in full text
4. Methods and endpoints
- Exposure / intervention
Added/free sugar intake (% energy) and sugar sources (SSB, treats, toppings)
- Comparator
Intake categories, lowest risk at 7.5-10% energy
- Endpoints
All-cause, cardiovascular and cancer mortality
- Statistical methods
Multivariable Cox proportional hazards
5. Actual results
- Results
Lowest mortality with added sugar intakes of 7.5-10% of energy in both cohorts. Intakes >20% energy were associated with 30% higher mortality; intakes <5% energy were also associated with higher risk (23% in MDCS; 9%, non-significant, in NSHDS). Similar U-shaped associations for cardiovascular and cancer mortality in MDCS. SSB intake was positively associated with mortality; intake of treats was inversely associated.
- Absolute risks
not reported in abstract
- Authors' conclusion
High sugar intake is associated with increased mortality risk; risk is also increased among low sugar consumers; associations depend on sugar source.
6. Strengths
- Two independent cohorts
- Detailed diet method in MDCS
- Source-specific analysis
7. Weaknesses
- Observational; residual confounding and reverse causation possible for low intakes
- Single baseline diet measurement
- Abstract only reviewed
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
Low-intake group may include people who reduced sugar because of illness.
9. Assessment of the statistical interpretation
The U-shape is an association; the excess risk at low intake is hard to explain causally and may reflect reverse causation or measurement issues. The upper end (>20% energy) supports limiting sugar.
10. Relevance to the specific claim
The fairest supporting-side evidence found for C-SUG-01: moderate sugar intake (7.5-10% energy) was not associated with harm. It does not support 'any amount is beneficial' or eating a kilogram: intakes above 20% of energy were associated with 30% higher mortality.
11. Independent contrary findings
WHO 2015, EFSA 2022 and umbrella reviews (I-SUG-02, I-SUG-104) support limiting free sugars.
12. Transferability to Germany and Europe
Directly European data.
13. Overall methodological judgement
Shows that the harm of sugar is dose- and source-dependent; refutes 'unlimited sugar is good' while acknowledging that moderate amounts were not associated with higher mortality.
| 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 | mixed |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Why low intakes were associated with higher mortality.
15. Linked fact checks
- White sugar is the greatest product humans ever made; any amount of sugar per day is beneficial, and one can eat a kilogram of white sugar or honey. – Studies with mixed or unclear results