PreDiabetes, Overweight and Obesity
Conditions
Brief summary
Prediabetes is a precursor of type 2 diabetes and an independent risk factor for cardiovascular disease, and currently affects one-quarter of the population of the United States. Individuals of overweight or obese BMI are at particular high risk for incident diabetes. A major modifiable risk factor for type 2 diabetes is poor dietary quality, and improvement of dietary quality can effectively delay and even prevent type 2 diabetes. Interventions to improve dietary quality thus far, however, rely on short-term intensive clinically designed meals replacing the entire diet which have poor sustainability. Persistent improvements to daily dietary patterns are often difficult without directed guidance, and overall dietary quality in the United States remains poor. The identification of a practical, daily dietary intervention to improve dietary quality and prevent diabetes in those at high risk remains unknown. The investigators propose to enroll 40 individuals with diagnosed prediabetes into a randomized controlled pilot study and provide a daily walnut supplementation intervention to determine feasibility and acceptability of the supplement. The investigators will then determine preliminary efficacy on metabolic markers and will investigate associations between dietary quality and circulating levels of branched-chain amino acids. The goal is to implement a whole-food supplement to improve dietary quality in patients with prediabetes as a tool for future type 2 diabetes prevention.
Interventions
DRUGWalnuts
1 ounce of individually wrapped, raw walnuts to be consumed daily replacing a high-refined carbohydrate food.
Sponsors
University of California, San Francisco
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
1. Male or female between 18-65 years of age at baseline living in the San Francisco Bay area. 2. BMI\>25 m/kg2 (or \>23 m/kg2 for individuals of Asian or South Asian ethnicity) 3. Documentation of prediabetes diagnosis as evidenced by the following criteria: 1. A fasting glucose 100-125 mg/dL, or a HbA1c measurement of 5.7-6.4%, OR a diagnosis of prediabetes or impaired fasting glucose in the past 6 months, identified through an electronic medical record query from patients at UCSF and through outside recruitment in the surrounding community 2. We will confirm eligibility of potential participants by repeating fasting capillary blood glucose measurements at the baseline visit to ensure that they have prediabetes 4. Written informed consent and ability for subject to comply with the requirements of the study.
Exclusion criteria
1. Pregnant or breastfeeding women at enrollment. 2. Presence of a condition or abnormality that in the opinion of the Investigator would compromise the safety of the patient or the quality of the data, such as diverticulosis or diverticulitis. 3. Tree or peanut allergies 4. Unwilling to consume a daily walnut supplement. 5. Diagnosis of diabetes 6. On glucose lowering medications 7. Dietician-managed dietary intake, or personal or medical dietary restrictions that do not allow consumption of walnuts 8. Malabsorptive conditions including intestinal bypass surgery, pancreatitis, inflammatory bowel disease
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Palatability of Supplement | 12 weeks | Palatability was measured using a visual analog scale, the scale range is 0-100, with 100 being the Most Pleasant. |
| Number of Participants Recruited and Retained | 12 weeks | Number of participants recruited and retained |
| Adherence to the Intervention | 12 weeks | Adherence to the intervention was determined through daily food diaries. Participants detailed daily consumption of the walnut supplement on a calendar provided at the outset of the study. Percentage was determined as number of days consuming supplement over 84 days total. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Fasting Glucose | 0 weeks and 12 weeks | Change in fasting glucose |
| Change in Low Density Lipoprotein Levels | 0 weeks and 12 weeks | Change in low density lipoprotein levels from baseline to 12 weeks |
| Change in Hemoglobin A1c | 0 weeks and 12 weeks | Change in percentage of Hemoglobin A1c |
| Change in Diet Quality | 0 weeks and 12 weeks | Change in diet quality measured by Healthy Eating Index-2010 Score (0 - 100). Higher scores indicate better diet quality. |
Other
| Measure | Time frame | Description |
|---|---|---|
| Number of Participants Who Had Plasma Metabolomics Performed | 0 weeks and 12 weeks | Plasma metabolomics performed as an exploratory outcome for all participants. This outcome represents number of participants who had a successful blood draw at both baseline and 12 weeks sent to the laboratory with usable data recovered. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Walnuts Now Will receive and be instructed to consume 1-oz individually wrapped daily walnut supplement packages for 12 weeks during intervention.
Walnuts: 1 ounce of individually wrapped, raw walnuts to be consumed daily replacing a high-refined carbohydrate food. | 8 |
| Walnuts Later Will receive diet and exercise guidance at beginning of study. At end of study, will receive 12 weeks of a walnut supply to be consumed at their discretion after the study is complete. | 10 |
| Total | 18 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Lost to Follow-up | 0 | 1 |
Baseline characteristics
| Characteristic | Total | Walnuts Now | Walnuts Later |
|---|---|---|---|
| Age, Continuous | 56.3 years | 55.4 years | 57.1 years |
| Body Mass Index | 33 kg/m^2 STANDARD_DEVIATION 5 | 30.4 kg/m^2 STANDARD_DEVIATION 4.1 | 35.6 kg/m^2 STANDARD_DEVIATION 5.9 |
| Fasting glucose | 107.6 mg/dL STANDARD_DEVIATION 17.9 | 109.5 mg/dL STANDARD_DEVIATION 24.6 | 106 mg/dL STANDARD_DEVIATION 11.5 |
| Hemoglobin A1c | 5.9 percentage of Hemoglobin A1c STANDARD_DEVIATION 0.6 | 5.8 percentage of Hemoglobin A1c STANDARD_DEVIATION 0.8 | 5.9 percentage of Hemoglobin A1c STANDARD_DEVIATION 0.3 |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 3 Participants | 1 Participants | 2 Participants |
| Race (NIH/OMB) Black or African American | 3 Participants | 1 Participants | 2 Participants |
| Race (NIH/OMB) More than one race | 1 Participants | 0 Participants | 1 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 11 Participants | 6 Participants | 5 Participants |
| Region of Enrollment United States | 18 Participants | 8 Participants | 10 Participants |
| Sex: Female, Male Female | 10 Participants | 5 Participants | 5 Participants |
| Sex: Female, Male Male | 8 Participants | 3 Participants | 5 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 8 | 0 / 10 |
| other Total, other adverse events | 0 / 8 | 0 / 10 |
| serious Total, serious adverse events | 0 / 8 | 0 / 10 |
Outcome results
Primary
Adherence to the Intervention
Adherence to the intervention was determined through daily food diaries. Participants detailed daily consumption of the walnut supplement on a calendar provided at the outset of the study. Percentage was determined as number of days consuming supplement over 84 days total.
Time frame: 12 weeks
Population: Adherence was not measured in the control group who did not receive the walnut supplement.
| Arm | Measure | Value (MEAN) |
|---|---|---|
| Walnuts Now | Adherence to the Intervention | 74.7 percentage of days |
Primary
Number of Participants Recruited and Retained
Number of participants recruited and retained
Time frame: 12 weeks
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| Walnuts Now | Number of Participants Recruited and Retained | 8 Participants |
| Walnuts Later | Number of Participants Recruited and Retained | 9 Participants |
Primary
Palatability of Supplement
Palatability was measured using a visual analog scale, the scale range is 0-100, with 100 being the Most Pleasant.
Time frame: 12 weeks
Population: Palatability was not measured in the control group who did not receive the walnut supplement intervention.
| Arm | Measure | Value (MEAN) |
|---|---|---|
| Walnuts Now | Palatability of Supplement | 87 score on a scale |
Secondary
Change in Diet Quality
Change in diet quality measured by Healthy Eating Index-2010 Score (0 - 100). Higher scores indicate better diet quality.
Time frame: 0 weeks and 12 weeks
Population: The Walnuts Later group did not complete the food frequency questionnaire required to assess change in diet quality. As the primary outcome was feasibility of recruitment and retention, we chose to analyze diet quality data only in those participants who provided these data.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Walnuts Now | Change in Diet Quality | 2.1 score on a scale | Standard Deviation 11.9 |
| Walnuts Later | Change in Diet Quality | 2.9 score on a scale | Standard Deviation 6.2 |
Secondary
Change in Hemoglobin A1c
Change in percentage of Hemoglobin A1c
Time frame: 0 weeks and 12 weeks
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Walnuts Now | Change in Hemoglobin A1c | -0.05 percentage of A1c | Standard Deviation 0.13 |
| Walnuts Later | Change in Hemoglobin A1c | -0.08 percentage of A1c | Standard Deviation 0.21 |
Secondary
Change in Low Density Lipoprotein Levels
Change in low density lipoprotein levels from baseline to 12 weeks
Time frame: 0 weeks and 12 weeks
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Walnuts Now | Change in Low Density Lipoprotein Levels | -8.4 mg/dL | Standard Deviation 15.5 |
| Walnuts Later | Change in Low Density Lipoprotein Levels | -0.5 mg/dL | Standard Deviation 13.1 |
Secondary
Fasting Glucose
Change in fasting glucose
Time frame: 0 weeks and 12 weeks
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Walnuts Now | Fasting Glucose | -4.75 mg/dL | Standard Deviation 9.8 |
| Walnuts Later | Fasting Glucose | 1.2 mg/dL | Standard Deviation 7.5 |
Other Pre-specified
Number of Participants Who Had Plasma Metabolomics Performed
Plasma metabolomics performed as an exploratory outcome for all participants. This outcome represents number of participants who had a successful blood draw at both baseline and 12 weeks sent to the laboratory with usable data recovered.
Time frame: 0 weeks and 12 weeks
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| Walnuts Now | Number of Participants Who Had Plasma Metabolomics Performed | 8 Participants |
| Walnuts Later | Number of Participants Who Had Plasma Metabolomics Performed | 9 Participants |