The purpose of this study is to determine if vinegar ingestion promotes beneficial changes to metabolic health parameters in healthy, overweight adults.

Recent research, in animal and human subjects, suggests that vinegar intake is inversely associated with insulin resistance, mood states and depression, inflammation, and other disease parameters. The study will be conducted as a randomized controlled trial in overweight adults to further examine these relationships and possible mechanisms. Although the mechanisms are not known, research suggests that changes in the gut microbiome, a response to the ingestion of the postbiotic acetic acid, may factor into the beneficial effects of vinegar ingestion. Through analyses of blood, changes in key blood metabolites associated with mood states (e.g., gamma-aminobutyric acid) as well as markers of gut health (e.g., LPS binding protein) and inflammation (e.g., CRP) will be assessed. Additionally mood state will be assessed using validated measures and determine risk for metabolic syndrome, a cluster of risk factors associated with many chronic conditions. It is hypothesized that vinegar ingestion will promote beneficial changes to these health parameters.

Inclusion Criteria:

• healthy
• non-smoker
• free of chronic disease by self-report
• able to speak, read, and understand English
• able to consent.
• BMI ≥ 25 and ≤ 35

Exclusion Criteria:

• adherence to specific diets for weight loss
• vegetarian
• report GERD or regular heartburn
• unwilling to consume vinegar daily for 4 weeks
• pregnant or lactating women
• recreational drug use, alcohol intake above recommendations (1 drink/day for women, 2 drinks/day for men - or none)
• competitive level physical training (e.g., physical activity above recommendations as set by the Physical Activity Guidelines for Americans)
• scoring 1 or higher on question 9 of the PHQ-9 questionnaire.

liquid vinegar (contains active dose of acetic acid) vinegar pill (contains only a trace of acetic acid)