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Effects of Sourdough Fermentation Duration and Acid Development on Postprandial Blood Glucose in Prediabetic Adults

Effects of Natural Sourdough Fermentation Duration and Acid Development on Postprandial Blood Glucose in Prediabetic Adults

Status
Completed
Phases
Unknown
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT06925451
Enrollment
5
Registered
2025-04-13
Start date
2025-04-04
Completion date
2025-12-15
Last updated
2026-01-23

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Insulin Resistance

Keywords

fermentation, pre-diabetes, sourdough bread, post-prandial glycemia

Brief summary

The primary intervention for management of prediabetes is lifestyle changes. Eating healthier and increasing physical activity was found to slow the progression of prediabetes into diabetes, reduce the risk of other diseases like cardiovascular disease and hypertension, and have a lasting impact even after the intervention is discontinued. Studies found that increasing the intake of fiber, pre- and probiotics, and fermented foods have been linked to improved glycemic biomarkers. The goal of this crossover randomized trial is to assess the relationship between lengthened fermentation time of sourdough bread, e.g., an increased amount of lactic acid and acetic acid in the bread product, and postprandial glycemic response in healthy adults with prediabetes.

Detailed description

Sourdough bread has been proven to have higher fiber content and contains beneficial microorganisms from the fermentation process and has been linked to reduced risk of various diseases like diabetes, cardiovascular disease, and dyslipidemia. The fermentation of sourdough bread products converts starch and sugar in the dough into resistant starches and other slower digesting compounds. Sourdough bread products also have a lower glycemic index value, meaning they do not cause the blood sugar to rise as quickly, thus slowing the release of insulin in the body, leading to reduced risk of insulin resistance. However, very few studies exist studying the effects of naturally fermented sourdough products in individuals with prediabetes. It is worth exploring if increasing the fermentation time of naturally fermented sourdough bread increases the effects on relevant biomarkers relating to postprandial glycemia and insulinemia in prediabetic adults. This study examined the acute effect of varying lengths of sourdough fermentation times on postprandial blood glucose levels over a 4-week period in adults with prediabetes (as evidenced by fasting glucose ≥100 or diagnosis by physician), but not taking diabetic medications. For each trial, the sourdough bread was ingested after an overnight fasting period in order to evaluate the effects of the bread when incorporated into the diet in place of breads made with baker's yeast. The goal of this crossover randomized trial was to assess the relationship between lengthened fermentation time, meaning an increased amount of lactic acid and acetic acid in the bread product, and glycemic and insulinemic response.

Interventions

OTHERsourdough bread 24

fermentation time=24 hours

OTHERsourdough bread 48

fermentation time=48 hours

OTHERsourdough bread 72

fermentation time=72 hours

OTHERyeast bread

no fermentation

Sponsors

Arizona State University
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
OTHER
Masking
SINGLE (Subject)

Intervention model description

The day prior to testing is standardized: no vigorous activity or alcohol consumption, and two bagels are to be consumed between 3 pm and 8 pm. Participants will begin an overnight fast starting around 10 pm (only water is to be consumed). The bagels will be provided at no charge. For each of the 4 test visits, participants arrive in a fasted state and a blood drop will be collected via finger prick to measure glucose. The 'test meal' will be consumed under observation within 8 minutes. The three fermented versions on the sourdough bread and the control bread will be fed using a four-block randomization process. Finger pricks will take place at 30, 60, 90, and 120 minutes post meal. The participant will be asked to complete hunger measures and report on the acceptability of the bread at the completion of testing.

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* prediabetes; not on metformin; no known food allergies or sensitivities; not supplementing pre/post biotics

Exclusion criteria

* following diet that restricts carbohydrates; medication use affecting blood glucose; acute illness; smoker; pregnant; lactating; GI tract surgery; not willing to follow protocol

Design outcomes

Primary

MeasureTime frameDescription
blood glucoseconducted at fasting and 30, 60, 90, and 120 minutes post-mealblood glucose will be measured using a glucometer and capillary blood from finger prick

Secondary

MeasureTime frameDescription
hunger ratingconducted at 120 minutes post-mealHunger rating will be determined using Likert scale. Anchors: not hungry at all and as hungry as I have ever felt. A higher score indicates greater hunger.
bread palatabilityconducted at 120 minutes post-mealbread palatability will be measured by Likert scale

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026