Daily vinegar ingestion has proven benefits in alleviating symptoms associated with type 2 diabetes and obesity, but this is the first time it has been linked to improved mood.
The main component of vinegar is acetic acid, which has an antioxidant role in biological systems, such as the brain, the study authors explain. In theory, this suggests vinegar may improve mental function by providing an exogenous source of acetate (a metabolite and derivative of acetic acid).
Evidence from a previous study on rats demonstrated a reversal in cognitive decline with acetate supplementation, however the effect of increased serum acetate from exogenous sources (including vinegar) is under-researched in humans, according to the researchers behind the current study.
Vinegar and brain health
The current placebo-controlled, randomised, parallel arm study, conducted by a team at Arizona State University, in the US, examined the impact of daily vinegar ingestion on mood states and urinary metabolites in 25 healthy college students.
Participants in the active study arm ingested two tablespoons of vinegar (Braggs, Liquid Apple Cider Vinegar) diluted in one cup water twice daily with meals for four weeks, and participants in the control arm consumed one vinegar tablet (General Nutrition Corporation Apple Cider Vinegar tablets) daily for four weeks. The liquid vinegar treatment provided 1.5 g acetic acid daily in comparison to the vinegar tablet that provided 0.015 g acetic acid daily.
A spot urine sample from the first morning void was collected at baseline and at study week four. Additionally, at baseline and at study week four, two validated, widely applied mood questionnaires were completed online: the Profile of Mood States (POMS) and the Center for Epidemiological Studies-Depression (CES-D) questionnaires.
Resulting data confirmed an increase in 10 of the 17 significant between-group metabolites in the liquid vinegar (VIN) group and a 20-34% reduction in self-reported depression scores in the same participants while there were slight increases in the control (CON) group.
Metabolomics data compiled by the team showed several metabolic alterations associated with apple cider vinegar ingestion and consistent for improved mood, including enzymatic dysfunction in the hexosamine pathway.
Scientists also noted an increase in glycine, serine, and threonine metabolism in the VIN group. Threonine increases glycine in the brain which, along with serine, impacts neurological health (brain function), they say.
The report states: “Serine has a role in the synthesis of sphingolipids and glycolipids which are important myelin constituents and also enhances dendritogenesis and axon lengths. Glycine is a neurotransmitter with trophic effects on neurons and a substrate in the synthesis of sarcosine.”
Scores from the CES-D baseline questionnaires suggested five VIN participants and four CON participants had elevated risks of suffering depression, while baseline results for POMS revealed one participant in each group below normative scores.
There were marginal changes to CES-D scores at week four with a reduction in the VIN group and an increase in the CON group. Conversely, individual mood states differed significantly for depression at week four. Mood scores improved in all categories in the VIN group but were consistently down in the CON group.
The scientists postulate that the study provides valuable insights into possible impacts of exogenous acetic acid on metabolism and suggest daily apple cider vinegar ingestion can lower depression scores in healthy college students under controlled conditions.
“With over 40% of college students self-reporting moderate-to-severe depression, a 77% increase over the past decade, simple and safe strategies that effectively reduce depression in this population are urgently needed," the report states. "These data warrant continued investigation of vinegar as a possible agent to improve mood state.”
However, they add that results may vary depending on the phytochemical profiles of the vinegar ingested and say the data warrants further investigation to underpin the evidence of vinegar as a possible agent to improve mood state.
Published online at: http://doi.org/10.3390/nu13114020
“Daily Vinegar Ingestion Improves Depression Scores and Alters the Metabolome in Healthy Adults: A Randomized Controlled Trial”
Authors : Carol S. Johnston * , Paniz Jasbi , Yan Jin, Shayna Bauer, Susanna Williams, Samantha N. Fessler and Haiwei Gu