Otherindependent cross-checkfull text checked I-FRU-04 in-depth review

Glycaemic index of dates

Glycemic indices of five varieties of dates in healthy and diabetic subjects.

Overview

Alkaabi JM et al.. Nutr J 2011 · PMID 21619670 · DOI 10.1186/1475-2891-10-59

Five date varieties had GI 46-55.

Does the study support the specific claim? Partly · Methodological quality: moderate

Original publication

Plain-language summary

Study explained simply

What did the researchers want to find out?: Dates GI
How was the study done?: Feeding test
How many people, animals or samples were studied?: 23
What was actually found?: Low GI
How large was the observed effect?: GI ~46-55
What do the results mean in everyday life?: Dates in moderation acceptable
What are the study's limitations?: Very small; order not randomised; only well-controlled diabetes; one-off servings
What does it say about Elawady's specific claim?: Supports dates in moderation
Do the results apply to Germany and Europe?: Moderate
What can explicitly not be concluded from this study?: Cannot show that large or unrestricted date portions are safe for people with diabetes

Scientific in-depth review

1. Full reference

Authors: Alkaabi JM et al.
Journal: Nutr J
Year: 2011
Identifier: PMID 21619670 DOI 10.1186/1475-2891-10-59
Verification: verified – PubMed efetch 2026-10-25
Retracted: no
Corrections: none
Extent checked: full text
Conflicts of interest and funding: Funded by a grant from the Abu Dhabi Food Control Authority (ADFCA); the dates were donated by Al Saad date factory; ADFCA staff performed composition analysis and are co-authors. Authors declare no competing interests.

2. Research question

GI of five date varieties

3. Study design and population

Study design: Other – Glycaemic index (GI) testing study, non-randomised within-subject sequence (3 glucose reference tests followed by 5 date varieties), plus chemical composition analysis; registered NCT01307904
Population: 13 healthy volunteers (7 F, 6 M; mean age 40.2 years, BMI 27.4) and 10 adults with type 2 diabetes controlled on diet with or without metformin (HbA1c <=8%; mean HbA1c 6.6%, age 40.8 years, BMI 30.7), recruited by poster advertisement in Al Ain
Country: United Arab Emirates (Al Ain)
Period: GI measurements March to June 2010
Sample size: 23
Inclusion and exclusion criteria: Healthy group truly healthy; T2D group HbA1c <=8% on diet +/- metformin. Excluded: BMI >40, prediabetes, pregnancy, GI disorders or surgery, gastroenteritis in prior 6 months, alcohol, smoking, any medication except metformin, HbA1c >8%, chronic or acute illness.

4. Methods and endpoints

Exposure / intervention: 50 g available carbohydrate from Tamer-stage dates (72.5-76.2 g flesh, about 7-10 dates) of 5 varieties: Fara'd, Lulu, Bo ma'an, Dabbas, Khalas; subjects blinded to variety
Comparator: 50 g glucose in 250 ml water, tested on 3 separate days (GI reference = 100)
Endpoints: Incremental area under the capillary glucose curve (healthy 0-120 min; T2D 0-180 min); GI; date composition (sugars, fibre, minerals, trace metals)
Statistical methods: GI calculated per subject as iAUC ratio vs mean of 3 glucose tests (Wolever calculator); Mann-Whitney U tests healthy vs T2D per variety; repeated-measures ANOVA across varieties; sample size based on literature (no formal power calculation).

5. Actual results

Results: Mean GI +/- SEM, healthy: Fara'd 54.0 +/- 6.1, Lulu 53.5 +/- 8.6, Bo ma'an 46.3 +/- 7.1, Dabbas 49.1 +/- 3.6, Khalas 55.1 +/- 7.7; T2D: 46.1 +/- 6.2, 43.8 +/- 7.7, 51.8 +/- 6.9, 50.2 +/- 3.9, 53.0 +/- 6.0. No significant differences healthy vs T2D (P 0.352-0.951) or between varieties (F=0.365, P=0.83). Composition: total reducing sugars 65.6-69.0% (fructose 28.6-33.3%, glucose 35.7-37.1%), crude fibre 1.8-2.6%.
Absolute risks: not applicable (no clinical outcomes); glycaemic load not reported. Reviewer calculation: a 50 g available-carbohydrate portion with GI 44-55 corresponds to a glycaemic load of roughly 22-28 per serving, i.e. high by the usual >=20 cut-off.
Authors' conclusion: The five date varieties have low GIs, and their consumption by people with diabetes did not result in significant postprandial glucose excursions, pointing to potential benefits of dates for diabetic subjects within a healthy balanced diet; caloric content must be accounted for.

6. Strengths

Standard GI methodology with glucose reference tested three times and capillary sampling
Includes people with T2D, extending usual GI testing
Subjects blinded to date variety; composition analysed by standard AOAC methods
Prospectively registered

7. Weaknesses

Very small sample (13 + 10); wide SEMs (up to 8.6 GI units)
Test order not randomised (authors' limitation); reference tests all before test foods
T2D group well controlled (mean HbA1c 6.6%), diet or metformin only; not generalisable to insulin-treated or poorly controlled diabetes
'No significant postprandial excursions' in T2D is a descriptive statement; no formal comparison against a threshold or a control food other than glucose
Single servings only; no long-term glycaemic outcomes
Glycaemic load and the large carbohydrate portion (7-10 dates) not discussed in GL terms
Industry donation of test food and food-authority funding (low risk of bias but noted)

8. Risk of bias

Orienting tool: No standard tool fits (GI measurement study); structured validity judgement
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: some concerns
Rationale: Overall unchanged. Valid for estimating GI of these date varieties; not evidence that unrestricted date intake is harmless in diabetes. Simplified single-reviewer judgement from the full text; a formal assessment would need two independent reviewers.

8. Risk of bias
Domain	Judgement	Rationale
Measurement method validity	low	Standard ISO-like GI protocol: 50 g available carbohydrate, glucose reference x3, capillary blood, validated glucometers (CV 2.2-2.65%).
Order/carry-over effects	some concerns	Non-randomised sequence; glucose tests all at start; washout day between tests.
Precision	high	n=13 and n=10; SEMs 3.6-8.6 GI units, so GI category (low vs medium) uncertain for several varieties.
Generalisability	some concerns	Five UAE Tamer-stage varieties; well-controlled T2D only.
Selective reporting / interpretation	some concerns	Conclusion of 'no significant excursions' and 'potential benefits' extends beyond a GI measurement; glycaemic load not reported.

Full-text review (25 October 2026): Added period (March-June 2010), portion size (72.5-76.2 g, 7-10 dates), composition, inclusion/exclusion, non-randomised order (author-stated limitation), registration, funding (ADFCA) and date donation by a factory; noted glycaemic load not reported (reviewer calculation ~22-28 per portion). Bias overall unchanged with structured domains.

9. Assessment of the statistical interpretation

GI point estimates 44-55 (low to borderline medium) with wide SEMs; non-significant group comparisons in very small samples do not show equivalence. The 50 g carbohydrate portion used (7-10 dates) carries a high glycaemic load.

10. Relevance to the specific claim

Context for C-FRU-05 and GL consistency in C-FRU-01.

11. Independent contrary findings

12. Transferability to Germany and Europe

Moderate.

13. Overall methodological judgement

Dates tested have low-to-borderline GI; portion size (glycaemic load) and total energy remain relevant, especially for people with diabetes. Weak evidence for long-term benefit or safety of high intake.

Multidimensional assessment
Multidimensional assessment
Authenticity of the source	verified
Methodological quality	moderate
Risk of bias	some concerns
Precision of results	low
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

Long-term glycaemic effects of habitual date intake in diabetes; effects in insulin-treated or poorly controlled diabetes; Egyptian varieties (e.g. Siwi, Hayani) and other ripening stages.

15. Linked fact checks

Sweet fruits such as dates, grapes, figs and mango need not be avoided; conventional diets wrongly restrict them and push bland fruit. – Studies supporting the claim
Watermelon and melon (cantaloupe) should be avoided; the archive's food page supports this with studies showing that a high dietary glycaemic load raises type 2 diabetes risk. – Studies with mixed or unclear results