Freeze-dried blueberries 26 g,
does it really help with Improved insulin resistance and tissue insulin sensitivity?
research showsThe verdict is D with 28 points. In a six-month trial funded and supplied by the blueberry council, the registered primary outcomes of insulin resistance and insulin sensitivity did not improve. Better endothelial function was a different secondary endpoint. Registration submission and study start were in the same month, so their exact order cannot be established.
ads claimAnthocyanin content or a vascular secondary result cannot be relabeled as improved insulin resistance. This verdict addresses the registered metabolic endpoint.
Useful facts when choosing a product
- The intervention was 26 g freeze-dried powder, not whole fresh fruit, and was equivalent to about 150 g or one cup of blueberries.
- Anthocyanins are present in blueberries, but composition does not establish better insulin resistance after six months.
- Verdict 289 is C with 58 points for blueberry concentrate and memory or cognition, a different form and outcome.
Chamgap Semantic Classification Code
Candidate index · review held
F.freeze-dried-blueberry-powder.food.insulin-resistance-and-tissue-insulin-sensitivity.improve.placeboFoods and beverages > Freeze-dried blueberry powder > Food consumption > insulin resistance and tissue insulin sensitivity > Improvement claim > Placebo
An automated migration candidate, not an issued permanent code; exact claim scope remains under review. This machine-generated migration candidate helps retrieval but is not a permanent assignment. The original verdict ID and URL remain authoritative.
What the research actually shows
NCT02035592 registration submission and study start were both in January 2014, so their exact order cannot be established. The registered primary outcomes of insulin resistance and insulin sensitivity matched the paper and were null. The US Highbush Blueberry Council funded the study and supplied materials; USDA oversight and UK BBSRC support were also reported. Analysis used 115 completers from a target of 144.
Why this is classified as D (28)
The registered surrogate primary outcomes matched the paper and were null in one industry-supported trial, without repeated refutation or a pooled confidence interval. Registration timing relative to study start is uncertain. Small enrollment, roughly one-fifth noncompletion, and completer analysis yield D with 28 points.
Counterpoint. Improved flow-mediated dilation supports a separate vascular hypothesis but does not rescue the insulin-resistance claim.
Rejudgment record. Cross-check applied — Cross-checked the prespecified endpoint, analysis denominator, result, registration timing, and funding against the article and NCT02035592
| Endpoint | S | Surrogate marker - laboratory or imaging measures |
| Replication | R1 | Single confirmatory trial |
| Independence | I1 | Mixed funding sources |
| Effect size | E0 | Null |
| Precision | CX | No pooled confidence interval could be confirmed |
Stored derived and displayed grades match; this is not a current recalculation or validity check (D).
Sub-claim grades by effect
This ingredient is marketed for several effects. A single overall grade blends strong and weak claims together, so each effect is graded separately here. The overall grade reflects the strongest disconfirming or core claim.
| Effect (sub-claim) | Grade | Basis |
|---|---|---|
| Blueberries contain anthocyanins | D | This is a composition fact separate from the graded clinical claim. |
| Twenty-six grams of freeze-dried blueberries improves insulin resistance | D | The registered primary outcome matched the paper and was null. |
Cross-check — AI research and Codex final gate
Evidence Table
| Study | Design | Sample | Funding | Endpoint | Result | Weight |
|---|---|---|---|---|---|---|
| Curtis PJ et al., American Journal of Clinical Nutrition, 2019 | Double-blind placebo-controlled parallel trial, six months | Target 144; 115 completers analyzed, 37, 39, and 39 | US Highbush Blueberry Council funding and materials; USDA oversight; BBSRC support | HOMA-IR and tissue-specific insulin sensitivity | Registered primary outcomes null; secondary FMD +1.45 percentage points, 95% CI 0.83 to 2.10 | Registration and study start were in the same month, leaving order uncertain; registered primary outcomes matched the paper and were null |
Receipt — 2 References
All 2 cited sources were verified for existence at the original page (as of 2026-08-02).
Final verification and publication gate: Codex · Evidence date: 2026-08-02 · Corrections: none
Cite this verdict
[Chamgap] Freeze-dried blueberries 26 g x insulin resistance — Evidence Grade D·28. 2 cited sources checked. Source: https://chamgap.com/en/verdicts/blood-sugar/freeze-dried-blueberries-26g-insulin-resistance/ · CC BY 4.0CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.
What this document does and does not do
Chamgap is an information source. It reports what research has and has not confirmed; it does not tell readers what to take or buy. That decision belongs to readers and, when needed, medical or legal professionals. This verdict reflects literature available up to the search date and may change as new research appears. Nothing here is medical advice.