Alkaline Diet for Insulin Sensitivity

The aim of the study is to test the effect of increasing the body pH acutely with an alkali (NaHCO3) prior to a high acid load meal on glucose metabolism in non-diabetic men and women.

This is a double-blind placebo-controlled randomised study with a crossover design.

Study Procedures:

Two (2) meal studies will be performed 1 to 2 weeks apart. Studies will include collecting fasting blood to assess circulating glucose, insulin, C-peptide, free fatty acids, glucagon-like peptide-1, acid/base markers, including electrolytes (EUC) and venous blood pH. Participants will then be either administered sodibic (1680 mg) or matching placebo and a standardised Western style/high acid load meal. Investigators and participants will be blinded to the intervention. Blood will be drawn every 15 min in the first hour and then every 30 min for 3 hours in total. Arterial stiffness and appetite score will be evaluated at ½ h intervals.

Sample size: 30

sample size calculation: To detect a difference in area under the curve (AUC) of venous blood pH with a paired crossover design, 32 individuals will be required with statistical power 1-β>0.8 (allowing for drop-out).

statistical considerations: Differences between AUC of outcome measures post sodium bicarbonate vs. placebo will be tested using paired t-tests. Two-way repeated measure ANOVA tests will be conducted to assess differences in the response to the meal with sodium bicarbonate vs. placebo.

Inclusion criteria

• Age range: 22-65
• Disease status: Healthy.
• Laboratory parameters: Fasting plasma glucose <7 mmol/L, HbA1c <6.5% (48 mmol/mol).
• Willingness to give written informed consent and willingness to participate and comply with the study.

Exclusion criteria

• Individuals with a personal history of diabetes, hypertension, cardiovascular disease, kidney disease, respiratory disease or inflammatory disease.
• Individuals treated with medications known to affect insulin sensitivity.
• Individuals with fasting plasma glucose ≥7 mmol/L, HbA1c ≥6.5% (48 mmol/mol).
• Individuals with an unstable body weight in the past 3 months (+/- 2 kg or more).
• Individuals with a history of a psychological illness or condition that may interfere with the participant's ability to understand the requirements of the study.
• Individuals who smoke.
• Individuals who consume more than 40 g of alcohol daily.