Propionic acid (PA) is used as a preservative in foods such as cheeses, baked goods, or additive for artificial fruit flavors. The U.S. Environmental Protection Agency considers it safe and therefore, has no limitation on its use. Since PA has been shown before to serve as a substrate for glucose production in the liver, the purpose of this study is to find out if PA intake causes changes in levels of glucose, insulin and other important hormones following a meal.

This research study will compare PA to placebo. The placebo looks exactly like the active substance, but it does not contain any active agent (PA). Placebos are used in research studies to see if the results are due to the study drug or to other reasons.

The investigators plan to have 20 subjects take part in this study at the Brigham and Women's Hospital (BWH).

-To test whether PA, added as food supplement to humans, results in altered post-prandial metabolism. The investigators propose to conduct a double-blind, randomized, placebo controlled, cross-over study in which blood levels of metabolites and hormones will be measured in healthy volunteers following a mixed meal test without or with PA.

Study design:

This is a double-blind, randomized, placebo controlled, cross-over study. Twenty volunteers who meet the inclusion/exclusion criteria will be randomized into two groups, provided with a mixed meal without or with calcium proprionate (also known as E282). A week later, participants will be provided with a mixed meal again, following cross-over of the groups. Blood will be collected at baseline, and every 30 minutes for 4 hours.

Study Subjects:

20 healthy male and female volunteers (ages 18 to 65 years) with a body mass index (BMI) of 20 to <30 Kg/m2.

Inclusion Criteria:

• Age 18-65 years
• Good health as evidenced by history and physical exam
• BMI: 20-29.9 kg/m2

Exclusion Criteria:

• Fasting plasma glucose >110 mg/dL
• HbA1c >6.0%
• Significant current illness other than treated hypothyroidism
• BP >135/85 or systolic BP <90 mm Hg
• Hepatic disease (transaminase > 3 times normal)
• Renal impairment (Creatinine clearance <60 ml/min)
• History of drug or alcohol abuse
• Participation in any other concurrent clinical trial
• Pregnant women
• History of food allergies.