Glucose Control, Nutrition, Precision Medicine, Prediabetes (Insulin Resistance, Impaired Glucose Tolerance)
Conditions
Keywords
Nutrition, Precision Medicine, Precision Nutrition, Glucose Control, Impaired Glucose Tolerance, Insulin Resistance, Prediabetes
Brief summary
The goal of this study is to learn whether eating a small serving of almonds before meals can improve blood sugar control in adults who have early signs of problems with blood sugar regulation. The main questions it aims to answer are: 1. Does eating almonds before a meal reduce the rise in blood sugar after eating? 2. Do some people consistently benefit more than others from eating almonds before meals?
Detailed description
Large rises in blood sugar after eating are an early warning sign of type 2 diabetes, and simple dietary strategies may help lower this risk. This study aims to understand whether eating a small serving of almonds before meals can help reduce postprandial blood sugar levels in adults who are at increased risk for developing type 2 diabetes. Participants will take part in two phases of the study: one conducted in a research clinic to carefully measure short-term blood sugar responses, and another conducted while participants follow a provided diet at home over a longer period. Sometimes participants will eat almonds before meals, and sometimes they will not. The study hypothesis is that eating almonds before meals will lower blood sugar rises after eating, and that some people will benefit more than others in a consistent way that can be observed both in the clinic and during everyday living.
Interventions
DIETARY_SUPPLEMENTPremeal almond ingestion
Premeal almond ingestion (18 g; \~100 kcal) 30 minutes prior to meal
Sponsors
Pennington Biomedical Research Center
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Investigator, Outcomes Assessor)
Intervention model description
The study consists of two phases using a crossover interventional design. In Phase 1, participants complete two cross-over trials (i.e., a total of four acute visits), including twice with an almond preload (active condition) and twice without (control condition). In Phase 2, participants complete one cross-over trial (i.e., a total of two 10-day study periods), including one with an almond preload prior to each meal (active condition) and one without (control condition). Given the repeated crossover nature of Phase 1 and the single crossover nature of Phase 2 of the study, there are a total of 8 possible visit sequences (i.e., "arms").
Eligibility
Sex/Gender
ALL
Age
25 Years to 50 Years
Healthy volunteers
Yes
Inclusion criteria
* Adults aged 25-50 years * Females over 40 years must have had a cycle in the last 6 months * Body mass index (BMI) at least 18.5 and at most 55.0 kg/m2 * Impaired blood glucose by at least one of the following criteria: * Fasting blood glucose at least 100 mg/dL (5.6 mmol/L) and less than 125 mg/dL (6.9 mmol/L) * HbA1c at least 5.7% and less than 6.5% * Willing and able to comply with study foods * Willing and able to ingest acetaminophen as part of study procedures * Able to read, speak, and understand English
Exclusion criteria
* Weight change ≥5% in past 6 months, actively trying to lose weight, or unwilling to remain weight stable throughout the study based on self-report * Recent history within past 12 months of medical provider-diagnosed cardiovascular, renal, or liver disease that required treatment * Current or past diagnosis of cancer (except skin cancer) in the last 5 years * Current or past diagnosis of type 1 or type 2 diabetes * Recent history within past 12 months of medical provider-diagnosed gastrointestinal or neurological disorders if not managed/stable for at least 3 months (with or without treatment) * Recent history within past 12 months of medical provider-diagnosed psychiatric disorders including eating disorders or severe depression if not managed/stable for at least 3 months (with or without treatment) * Food allergies or other reasons preventing consumption of study foods * Any glucose-lowering medication except biguanides (e.g., Metformin) if stable for at least 3 months or incretins (i.e., GLP-1RA-based) if stable for at least 3 months * Current smoking or vaping or history of smoking or vaping in the past 6 months * Binge and/or heavy drinking (i.e., \>3 drinks on any given occasion and/or \>7 drinks/week) * Currently pregnant or planning to become pregnant or breastfeed in the next 3 months by self-report
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Postprandial glucose assessed during acute meal test | Days 1-4: -35 minutes, -5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 120 minutes, 180 minutes relative to ingestion of premeal almonds at -30 minutes (if applicable) and the mixed meal tolerance test at 0 minutes. | The primary endpoint will be the difference in plasma glucose incremental area under the curve (iAUC) assessed via intravenous blood sampling over three hours following a standardized mixed meal tolerance test (MMTT) with premeal ingestion of 18 g of almonds 30 minutes prior (MMTT+) compared to without (MMTT-). This effect will be averaged across the replicated acute challenge visits in the repeated crossover design. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Interindividual variability in the postprandial glucose assessed during acute meal test | Days 1-4: -35 minutes, -5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 120 minutes, 180 minutes relative to ingestion of premeal almonds at -30 minutes (if applicable) and the mixed meal tolerance test at 0 minutes. | Variability in response to the single-dose, acute premeal almond supplementation prior to the MMTT will be characterized according to previously established procedures using Pearson's correlation between the first and second replicate of the control-adjusted treatment effect (i.e., MMTT+ vs MMTT-). That is, the correlation between the difference in iAUC during the first crossover trial (i.e., iAUC during MMTT+ minus iAUC during MMTT-) and the difference in iAUC during the second crossover trial (i.e., iAUC during MMTT+ minus iAUC during MMTT-). |
| Consistency between acute glycemic response and longer-term glycemic control | Days 1-4: Days 1-4: -35 minutes, -5 minutes, 15 minutes, 30 minutes, 60 minutes, 90 minutes, 120 minutes, 180 minutes relative to ingestion of premeal almonds at -30 minutes (if applicable) and the mixed meal tolerance test at 0 minutes. Days 5-25 | Whether the individual glucose-lowering effect of the almond preload observed during the acute, repeated crossover, controlled in-laboratory MMTT predicts an individual's glycemic control during the 10-day, free-living, controlled-feeding phase in which almonds will be consumed thrice daily prior to each main meal on the background of a Standard American diet. We will evaluate this via the regression coefficient derived from a linear regression with the magnitude of the acute treatment effect in Days 1-4 (i.e., the difference in iAUC between MMTT+ and MMTT- averaged between both crossover trials) as the predictor and the magnitude of the treatment effect in Days 5-25 (i.e., the difference in average iAUC across the 10-day controlled feeding diet periods between MMTT+ and MMTT-) as the outcome. |
Countries
United States
Contacts
CONTACTKaja Falkenhain, PhD
Outcome results
None listed