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?
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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
25
Premeal almond ingestion (18 g; \~100 kcal) 30 minutes prior to meal
Pennington Biomedical Research Center
Baton Rouge, Louisiana, United States
Postprandial glucose assessed during acute meal test
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.
Time frame: 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.
Interindividual variability in the postprandial glucose assessed during acute meal test
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-).
Time frame: 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.
Consistency between acute glycemic response and longer-term glycemic control
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.
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Time frame: 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