Could taking vinegar every day help reduce depression?

By Priyanjana Pramanik, MSc.Reviewed by Susha Cheriyedath, M.Sc.Jul 21 2024

In a recent study published in the journal Nutrients, researchers in the United States investigated the effects of daily vinegar ingestion on depression symptoms in overweight, healthy adults.

Their results indicate that consuming vinegar daily over four weeks significantly improved self-reported depression scores, potentially due to enhancements in niacin metabolism.

Study: Daily Vinegar Ingestion Improves Depression and Enhances Niacin Metabolism in Overweight Adults: A Randomized Controlled Trial. Image Credit: kellyreekolibry / Shutterstock

Background

Depressive disorders, among the most common mental health burdens globally, have seen significant increases in prevalence over the past decade. Standard treatments, including medications and psychotherapy, have variable efficacy and can cause severe side effects.

This inconsistency has driven the search for alternative therapies. Vinegar, a solution of fermented acetic acid, has emerged as a potential dietary supplement with benefits for managing blood, weight reduction, and the risk of heart disease.

Previous studies suggest that vinegar might also improve depression symptoms by enhancing tryptophan metabolism, which is linked to increased serotonin production in the brain. However, further studies are needed to understand its efficacy.

About the study

Researchers conducted a randomized controlled trial to investigate the effects of daily vinegar ingestion on depression symptoms in overweight, healthy adults over four weeks. They hypothesized that vinegar would improve depression scores compared to a control treatment, exploring underlying mechanisms through metabolomics analyses.

Researchers recruited healthy, non-smoking women and men aged 18–45 with a body mass index (BMI) of 25–40 from a university community. Participants were excluded if they had chronic illnesses, were pregnant, lactating, vegetarians, or had a high alcohol intake.

They were randomly assigned to drink diluted vinegar (two tablespoons twice daily) or take a vinegar pill (one daily) for four weeks.

Before and after the trial, participants provided fasting blood samples, completed dietary recalls, and had their waist circumference, weight, and height measured. They also completed health history questionnaires and two depression assessments. Participants recorded their vinegar intake daily to monitor compliance.

Blood samples were analyzed using gas chromatography-mass spectrometry (GC-MS), a technique that identifies and measures the amounts of different chemicals in a sample. In GC-MS, the sample is vaporized and separated into its components by gas chromatography, and then the mass spectrometer identifies each constituent based on its mass. This method allowed researchers to detect and quantify metabolic changes in the blood.

Data analysis included statistical tests to compare changes in depression scores and metabolite levels between the groups.

Findings

The study, which took place from January to June 2023, involved 45 participants split into two groups: one took liquid vinegar (intervention), and the other took vinegar pills (control). By the end, 28 participants completed the study. Adherence to taking supplements was high for both the intervention and control groups.

Participants' baseline characteristics, including age and BMI, were similar across groups. Depression scores showed no significant differences between groups at the start. However, by week 4, the intervention group saw a 42% reduction in depression scores from one survey, the Patient Health Questionnaire-9 (PHQ-9), indicating improved mood, compared to an 18% reduction in the control group.

The metabolite analysis from the GC-MS allowed researchers to compare the intervention and control groups further. Three important chemicals—isobutyric acid, nicotinamide, and L-isoleucine—showed significant differences.

Specifically, nicotinamide (a form of vitamin B3) levels increased by 86% in the group that took liquid vinegar, while L-isoleucine levels decreased by 35% in the same group. This suggests that improvements in symptoms of depression in the group that took liquid vinegar could be linked to changes in nicotinamide levels.

Conclusions

This study examined the impact of liquid vinegar on depression and blood chemicals in adults without chronic diseases. While the intervention group experienced greater improvements in the PHQ-9 scores, this improvement became less certain when adjusted for initial scores.

The study had several strengths. It used well-validated tools for measuring depression. Additionally, the metabolite analysis using GC-MS revealed important changes in blood chemicals, particularly highlighting nicotinamide as a significant factor. The researchers also considered the potential impact of the frequency of vinegar intake on depression symptoms.

However, there were limitations. The sample size was small, with only 28 participants completing the trial, limiting the results' generalizability. The trial's short duration of four weeks may not be sufficient to observe long-term effects. Moreover, participants had relatively low baseline depression scores, which might have affected the observed impact of vinegar.

Future research should involve larger sample sizes, more extended study periods, and focus on individuals with clinical depression to better understand vinegar's long-term effects and underlying biological mechanisms on depressive symptoms.

Overall, this study suggests that daily vinegar intake might help reduce depression symptoms, but more research is needed to confirm these findings and understand how vinegar works in this context.