Nutcracker: Can Almond Nut Consumption Improve Nocturnal Glycaemic Control in Women With Gestational Diabetes Mellitus? (Nutcracker)

July 16, 2025 updated by: Guy's and St Thomas' NHS Foundation Trust

Nutcracker: Can Almond Nut Consumption Improve Nocturnal Glycaemic Control in Women With Gestational Diabetes Mellitus? A Randomised Controlled Trial

Gestational diabetes, affecting over one in six births globally, is a growing public health concern. Characterised by high blood glucose, it increases the risk of pregnancy complications and raises the mother's long-term risk of type 2 diabetes. Managing high fasting glucose, which reflects elevated overnight levels, is a key challenge. Night-time snacking-more common in women with gestational diabetes-is linked to higher fasting glucose, but the impact of snack quality is unclear. Almonds have been shown to improve glucose control in non-pregnant adults. This study will test whether almonds, as a night-time snack, can improve overnight glucose levels in pregnant women with gestational diabetes. Findings could support a simple, effective dietary strategy to improve outcomes for mothers and babies worldwide.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Gestational diabetes mellitus (GDM) is a significant and increasingly prevalent public health concern, affecting over one-sixth of births globally. A key challenge in its management is fasting hyperglycaemia, which may result from elevated nocturnal glucose concentrations. Nocturnal hyperglycaemia has been linked to an increased risk of large-for-gestational-age infants in women with GDM. These women are also more likely to snack at night, a behaviour associated with higher fasting glucose concentrations; however, the impact of snack quality on overnight glucose regulation remains unclear.

Almond consumption has been shown to improve glycaemia in individuals with prediabetes or type 2 diabetes, potentially through mechanisms such as carbohydrate displacement and the beneficial effects of their nutrient profile, particularly magnesium and monounsaturated fats. Despite this, research in pregnant populations-especially those with GDM-is limited.

This study will investigate whether consuming almonds as an evening snack for four weeks improves overnight glucose regulation in women with GDM. Participants will be randomised to receive either almonds or a nut-free, energy-matched control snack. Changes in glucose metabolism will be assessed to determine the potential role of almonds in dietary management of GDM.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
156

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Child
  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Age over 16 years
  2. Singleton pregnancy
  3. 25 to 31+6 weeks' gestation diagnosed with GDM using a standard clinical 75g oral glucose tolerance test (OGTT), as per the guidelines of the National Institute of Health and Care Excellence (NICE), and had their first post-diagnosis consultation (approx. 7-10 days later). The NICE criteria state that the diagnosis of GDM will be made with one or more glucose concentrations during the OGTT of >5.6 mmol/l in the fasting state; >7.8 mmol/l 2 hours after 75g glucose
  4. Planned antenatal care at the same centre
  5. GDm-Health (a digital app for the management of diabetes in pregnancy) used as part of their management for GDM
  6. Willing and able to give informed consent

Exclusion Criteria:

  1. Age under 16 years or over 55 years
  2. Multiple pregnancy
  3. Non-snack consumers
  4. Smokers
  5. Women who would work night shifts over the study period
  6. Women who have already commenced insulin for the treatment of GDM
  7. Allergy or intolerance to nuts
  8. Pre-existing medical conditions, including Type 1 or Type 2 diabetes, chronic coronary, renal or bowel disease or history of cholestatic liver disease or pancreatitis. Presence of gastrointestinal disorder or use of a drug which is likely to alter gastrointestinal motility or nutrient absorption, previous bariatric surgery
  9. Unwilling or unable to give informed consent

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Almond group
Participants in the almond group will consume 43 g of almonds daily for 28 days, divided into two equal portions: one in the afternoon and one in the evening.
Other: Almond Snack Intervention for Gestational Diabetes
This intervention involves daily consumption of 43 g of whole almonds, split into two portions (afternoon and evening), for 28 days in pregnant women diagnosed with gestational diabetes who habitually consume evening snacks.
Placebo Comparator: Control group
Participants in the control group will consume nut-free snacks (e.g., crackers or savoury biscuits) that are energy-matched to the almond snacks.
Other: Control (placebo) group
This control involves the daily consumption of a nut-free snack (2 portions) that reflects a 'typical snack' choice among pregnant women with gestational diabetes. It serves as a comparison to assess the specific impact of almond-based evening snacking on overnight glucose regulation.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
Mean nocturnal blood glucose (22.00-07.00h)
Time Frame: The primary endpoint will be assessed on day 14 and day 28 of the intervention.
The primary endpoint will be assessed on day 14 and day 28 of the intervention.

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Mean daytime glucose 07.00-22.00h
Time Frame: Assessed on day 14 and day 28 of the intervention.
Recommended glucose control target 3.5-7.8mmol/L, AUC <6.7mmol/L, AUC <7.8mmol/L
Assessed on day 14 and day 28 of the intervention.
Postprandial blood glucose
Time Frame: Assessed on day 14 and day 28 of the intervention.
Mean postprandial blood glucose for 1, 2 & 4 hours after dinner.
Assessed on day 14 and day 28 of the intervention.
Glucose variability
Time Frame: Assessed on day 14 and 28 of the intervention.
Glucose SD, glucose CV
Assessed on day 14 and 28 of the intervention.
Blood glucose indices
Time Frame: Assessed on day 14 and 28 of the intervention.
High and low blood glucose indices (HBGI & LBGI)
Assessed on day 14 and 28 of the intervention.
HbA1c
Time Frame: Assessed on day 0 and day 28 of the intervention.
Biochemical analysis of maternal blood
Assessed on day 0 and day 28 of the intervention.
Liver function
Time Frame: Assessed on day 0 and day 28 of the intervention.
Biochemical analysis of maternal blood: gamma-glutamyl transferase (GGT), alanine aminotransferase (ALT), aspartate aminotransferase (AST)
Assessed on day 0 and day 28 of the intervention.
Maternal metabolome (blood)
Time Frame: Assessed on day 0 and day 28 of the intervention.
Lipid measures, including lipoprotein particles (VLDL subdivided into six subclasses, IDL, LDL subdivided into three subclasses, and HDL subdivided into four subclasses), constituents within each lipoprotein particle type (triglycerides, total cholesterol, free cholesterol and cholesterol ester levels and phospholipid concentrations), fatty acids, amino acids, glycolysis related metabolites, ketone bodies and inflammatory markers.
Assessed on day 0 and day 28 of the intervention.
Maternal weight in kg
Time Frame: Assessed on day 0 and day 28 of the intervention.
Maternal weight and height will be combined to report BMI in kg/m^2
Assessed on day 0 and day 28 of the intervention.
Dietary intake using questionnaire
Time Frame: Assessed on or around day 0 (x2), day 14 (x 2) and day 28 (x2) of the intervention.
Assessment of dietary intake using Intake24, a validated digital dietary recall system based on the multiple-pass 24-hour recall
Assessed on or around day 0 (x2), day 14 (x 2) and day 28 (x2) of the intervention.
Assessment of appetite on a Likert scale
Time Frame: Assessed on day 0, day 14, and day 28 of the intervention.
Assessment of appetite on a 1-7 Likert scale (i.e., 1 = Not at all hungry, 7 = Extremely hungry)
Assessed on day 0, day 14, and day 28 of the intervention.
Physical activity using accelerometer
Time Frame: Assessed on days 0-28 of the intervention.
The accelerometer will record physical activity, such as average time spent in moderate, low, and sedentary activity
Assessed on days 0-28 of the intervention.
Stool
Time Frame: May be assessed on days 0, 14 and 28 of the intervention.
(Optional) may be collected and stored for microbiome analysis
May be assessed on days 0, 14 and 28 of the intervention.
Sleep quality using accelerometer
Time Frame: Assessed on days 0-28 of the intervention.
The accelerometer will measure sleep quality, such as sleep duration
Assessed on days 0-28 of the intervention.
Course of GDM
Time Frame: Assessed on days 0-28 of the intervention.
If medication is required for glucose control, such as metformin or insulin (dose, time of initiation)
Assessed on days 0-28 of the intervention.
Mode of delivery
Time Frame: Assessed at delivery.
Assessed at delivery.
Acceptability of the intervention using questionnaire
Time Frame: Assessed on day 28 of the intervention.
A dietary intervention acceptability questionnaire will be used to assess enjoyment, sensory aspects, gastrointestinal effects, palatability, and appetite sensations.
Assessed on day 28 of the intervention.
Birthweight
Time Frame: Assessed at delivery.
Assessed at delivery.
Neonatal head circumference
Time Frame: Assessed at delivery.
Assessed at delivery.
Neonatal sex
Time Frame: Assessed at delivery.
Assessed at delivery.
Gestational age
Time Frame: Assessed at delivery.
Assessed at delivery.
Neonatal complications
Time Frame: Assessed at delivery.
Assessed at delivery.
Maternal complications
Time Frame: Assessed at delivery.
Assessed at delivery.
Labour onset checklist
Time Frame: Assessed at delivery.
Assessed at delivery.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Guy's and St Thomas' NHS Foundation Trust

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
King's College London
Almond Board of California

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Sara L White, King's College London

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 1, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
October 1, 2025

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
October 1, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
May 12, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 16, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
July 17, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 17, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 16, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 325804

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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