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Vinegar before meals

Taking a small amount of vinegar, usually apple cider vinegar, with or shortly before a meal.

At a glance

  • Evidence: Small randomised crossover experiments show that vinegar taken with a starchy meal lowers the blood glucose response to that meal.Post-meal blood glucose response · Limited certainty · Randomized intervention
  • What’s uncertain: Every trial enrolled roughly ten participants and measured a single test meal, so the evidence describes an acute physiological response rather than a habit effect.
  • First step: If you try it, take roughly one to two teaspoons of vinegar with a meal containing starch rather than on its own; the acute effect was most consistent when vinegar was consumed with food.
  • Before you try it: Vinegar is acidic and can erode tooth enamel and irritate the mouth and oesophagus; dilute it, use a straw, and rinse with water afterwards. All precautions
Read the full takeaway

Acute glucose response

Small amounts of vinegar taken with a meal reduce the immediate rise in blood glucose after that meal in short experiments, and the effect depends on the meal containing complex carbohydrate.

Limits of the evidence

The evidence base is thin: the trials enrolled about ten people each, measured a single meal, and the longer randomised trials that do exist report HbA1c reductions of uncertain reliability, with pooled estimates ranging from -0.39 to -1.53 percentage points, heterogeneity of 91-99%, and no high-certainty GRADE result. Vinegar is best understood as a small acute effect, not a treatment.

A vintage vinegar bottleDiscussed byJessie InchauspéView statements ↓
NutritionLong-term healthUnder 10 min · Easy · Low
Reviewed Sep 23, 2026
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Scientific evidence

What the research shows

Outcome assessments based on research, including its uncertainties and limitations.

Post-meal blood glucose response

Finding: Benefit supportedCertainty: Limitedstudies found a benefit from doing this

Evidence basis: randomised trials

Small randomised crossover experiments show that vinegar taken with a starchy meal lowers the blood glucose response to that meal.

Population: Adults in small randomised crossover experiments: four trials with 9 to 10 participants each, one of which enrolled people with type 2 diabetes, and a separate trial of 12 healthy volunteers.

Research details

Summary

Small randomised crossover experiments show that vinegar taken with a starchy meal lowers the blood glucose response to that meal. Four crossover trials in adults with and without type 2 diabetes found that about two teaspoons of vinegar reduced post-meal glucose by roughly 20 percent compared with placebo when taken with a complex-carbohydrate meal, and the effect disappeared when vinegar was given with a monosaccharide drink or replaced with sodium acetate. A separate crossover trial in twelve healthy volunteers found a dose-response relationship between acetic acid and lower glucose and insulin responses, although the difference was no longer present when the response was calculated over 120 minutes.

Why this certainty

Rated Limited: the direction is consistent across independent crossover experiments, one of which shows a dose-response relationship, and the mechanism appears specific to starch digestion rather than to an inert effect of the drink. Certainty is held down because samples are very small, exposure is a single meal, the summary measure changes the answer, and no long-term outcome has been tested.

Limitations

Every trial enrolled roughly ten participants and measured a single test meal, so the evidence describes an acute physiological response rather than a habit effect. Blinding is difficult because vinegar tastes distinct, and several comparisons relied on within-subject meal challenges rather than free-living diets. The size of the effect varied with the type of carbohydrate, and the 120-minute analysis in one trial showed no difference from the reference meal, which suggests the effect depends on how the response is summarised. No trial measured HbA1c or clinical outcomes.

Effect estimate

About 10 g of vinegar with a complex-carbohydrate meal: postprandial glucose attenuated by 20 percent compared with placebo (four randomised crossover trials, 9 to 10 participants each).

Sources for this outcome:

Appetite and satiety

Finding: Benefit supportedCertainty: Very limitedstudies found a benefit from doing this

Evidence basis: randomised trials

One small crossover trial reported that vinegar with a bread meal increased subjective satiety ratings, with a dose-response relationship to acetic acid.

Population: Twelve healthy volunteers at a single research centre who consumed white wheat bread with three different levels of vinegar in randomised order after an overnight fast.

Research details

Summary

One small crossover trial reported that vinegar taken with a bread meal increased subjective satiety ratings, with a linear relationship between the amount of acetic acid and the satiety score and significant increases at 30, 90, and 120 minutes after the meal compared with the reference meal.

Why this certainty

Rated Very limited: a single small crossover trial with a subjective outcome, no blinding, and no measurement of the downstream behaviour that would make satiety meaningful. The internal dose-response is suggestive but cannot carry an outcome on its own.

Limitations

This is one trial in twelve people using a subjective rating scale, with no blinding possible because the interventions differ in taste. Satiety ratings are not the same as measured energy intake, and the trial did not test whether the change in satiety altered how much people ate or their weight over time. No independent replication was retrieved.

Sources for this outcome:

Long-term glucose control and clinical outcomes

Finding: Mixed evidenceCertainty: Very limitedstudies disagree, or the effect depends on who is studied

Evidence basis: randomised trials

Longer randomised trials report HbA1c reductions from regular vinegar, but the pooled estimates are large, heterogeneous and of low quality.

Population: Adults with type 2 diabetes in randomised trials of eight weeks or longer, including 6 studies with 317 patients, 9 studies with 10 arms of apple cider vinegar, 7 controlled trials, 25 clinical trials with 33 arms in 1,320 adults and one 8-week trial of 30 mL a day; the acute single-meal crossover studies remain the separate evidence base for postprandial glucose.

Research details

Summary

Taking vinegar regularly has been tested over weeks to months, not only at single meals. A meta-analysis of trials giving vinegar for 8 to 12 weeks found a small significant reduction in mean HbA1c of -0.39 percentage points (95% CI -0.59 to -0.18, I2 = 0%) while other long-term outcomes favoured vinegar without reaching significance. A separate systematic review and meta-analysis of six studies in 317 patients with type 2 diabetes found significantly better fasting blood glucose and HbA1c. Later reviews report much larger pooled effects: HbA1c -0.50 (95% CI -0.90 to -0.09, I2 = 91%) across nine studies of apple cider vinegar with no significant effect on LDL cholesterol, HDL cholesterol, fasting insulin or HOMA-IR; HbA1c -1.53 (95% CI -2.65 to -0.41) across seven controlled trials with fasting blood sugar -21.93 mg/dL, insulin higher by 2.06 microU/mL and no effect on HOMA-IR; and HbA1c -0.91 (95% CI -1.62 to -0.21, I2 = 98.9%) across 25 trials in 1,320 adults with no significant effect on BMI, HOMA-IR, insulin, triglycerides, LDL cholesterol or HDL cholesterol. An eight-week randomised trial of 30 mL of apple cider vinegar a day in adults with type 2 diabetes found a significant between-group difference in HbA1c (p < 0.001) and a fall in fasting glucose within the vinegar arm, but insulin and HOMA-IR rose in the vinegar group while falling in the control group (p < 0.001 and p = 0.04).

Why this certainty

Rated Very limited and recorded as Mixed evidence. Longer randomised trials and their meta-analyses do exist and most report lower HbA1c, which is why this outcome is no longer described as untested. Certainty stays at Very limited because the pooled effects range from small to implausible, heterogeneity reaches I2 = 91-99%, the syntheses overlap and are mostly small and short, several report no effect on insulin resistance, and one randomised trial found insulin and HOMA-IR moving in the adverse direction.

Limitations

The pooled estimates are mutually inconsistent in size, running from about -0.4 to -1.5 percentage points of HbA1c, and heterogeneity is severe wherever it is reported (I2 = 91% and 98.9%), so the largest estimates are not credible. Several of these syntheses overlap in the trials they include, none reports a high-certainty GRADE result, and the trials are short relative to the timescale over which diabetes complications develop. No trial reports a clinical endpoint such as cardiovascular events, mortality, weight or medication use, and the extreme estimates contrast with the absence of any effect on HOMA-IR or insulin in most of the pooled analyses. One eight-week randomised trial found insulin and HOMA-IR rising in the vinegar arm, an adverse-direction result for the mechanism the HbA1c estimates are meant to reflect.

Effect estimate

HbA1c mean difference -0.39 percentage points (95% CI -0.59 to -0.18, I2 = 0%) after 8 to 12 weeks of vinegar administration; HbA1c -0.50 (95% CI -0.90 to -0.09, I2 = 91%) across 9 apple cider vinegar studies; HbA1c -1.53 (95% CI -2.65 to -0.41) across 7 controlled trials with insulin higher by 2.06 microU/mL.

Sources for this outcome:

What people say

Who discusses this?

Public statements, with positions specific to each source and topic. These views do not determine the scientific evidence assessment.

What the research shows ↑

Practical steps and precautions

How to try it

  1. If you try it, take roughly one to two teaspoons of vinegar with a meal containing starch rather than on its own; the acute effect was most consistent when vinegar was consumed with food. Two teaspoons of 5% vinegar is roughly 1 g of acetic acid, which is the 10 g dose used in those acute crossover trials; the trials reporting HbA1c effects used 20 to 30 mL a day, and the satiety and dose-response findings come from higher doses of 18 to 28 mmol of acetic acid.
  2. Treat that amount as an editorial starting point from small crossover studies, not an established dose.
  3. Do not expect a benefit with a meal of simple sugars; vinegar did not change glucose response when taken with a monosaccharide drink.
  4. Keep this in proportion: the effect is on a single post-meal glucose curve, not on weight or long-term health.

Precautions

  • Vinegar is acidic and can erode tooth enamel and irritate the mouth and oesophagus; dilute it, use a straw, and rinse with water afterwards.
  • Do not take vinegar as a substitute for glucose-lowering medication, and discuss it with your prescriber if you take insulin or a sulfonylurea because of the risk of hypoglycaemia.
  • Undiluted vinegar has caused oesophageal injury and vinegar tablets have been associated with throat irritation; do not take it dry or in large amounts.
  • In an eight-week randomised trial in adults with type 2 diabetes, insulin and HOMA-IR rose in the apple cider vinegar group while falling in the control group, so regular vinegar should not be assumed to improve insulin sensitivity.

References

Examination of the antiglycemic properties of vinegar in healthy adults

Johnston CS, Steplewska I, Long CA, Harris LN, Ryals RH · Annals of Nutrition and Metabolism · 2010

Four randomised crossover trials examining vinegar dose, timing and formVerified from abstract
Open original source

Vinegar supplementation lowers glucose and insulin responses and increases satiety after a bread meal in healthy subjects

Ostman E, Granfeldt Y, Persson L, Bjorck I · European Journal of Clinical Nutrition · 2005

Randomised crossover trial with three vinegar doses and a reference mealVerified from abstract
Open original source

Diabetes Control: Is Vinegar a Promising Candidate to Help Achieve Targets?

Siddiqui FJ, Assam PN, de Souza NN, Sultana R, Dalan R, Chan ES · Journal of evidence-based integrative medicine · 2018

Systematic review and meta-analysis of clinical trialsVerified from abstract
Open original source

A systematic review and meta-analysis: Vinegar consumption on glycaemic control in adults with type 2 diabetes mellitus.

Cheng LJ, Jiang Y, Jiang Y, Wu VX, Wang W · Journal of advanced nursing · 2020

Systematic review and meta-analysis of interventional studiesVerified from abstract
Open original source

The effect of apple cider vinegar on lipid profiles and glycemic parameters: a systematic review and meta-analysis of randomized clinical trials.

Hadi A, Pourmasoumi M, Najafgholizadeh A, Clark CCT, Esmaillzadeh A · BMC complementary medicine and therapies · 2021

Systematic review and meta-analysis of randomized clinical trialsVerified from abstract
Open original source

Effects of apple cider vinegar on glycemic control and insulin sensitivity in patients with type 2 diabetes: A GRADE-assessed systematic review and dose-response meta-analysis of controlled clinical trials.

Arjmandfard D, Behzadi M, Sohrabi Z, Mohammadi Sartang M · Frontiers in nutrition · 2025

GRADE-assessed systematic review and dose-response meta-analysis of controlled trialsVerified from abstract
Open original source

The Effects of Apple Cider Vinegar on Cardiometabolic Risk Factors: A Systematic Review and Meta-analysis of Clinical Trials.

Tehrani SD, Keshani M, Rouhani MH, Moallem SA, Bagherniya M, Sahebkar A · Current medicinal chemistry · 2025

Systematic review and meta-analysis of clinical trialsVerified from abstract
Open original source

The improvement effect of apple cider vinegar as a functional food on anthropometric indices, blood glucose and lipid profile in diabetic patients: a randomized controlled clinical trial.

Jafarirad S, Elahi MR, Mansoori A, Khanzadeh A, Haghighizadeh MH · Frontiers in clinical diabetes and healthcare · 2023

Randomized controlled clinical trialVerified from full text
Open original source

Esophageal injury by apple cider vinegar tablets and subsequent evaluation of products.

Hill LL, Woodruff LH, Foote JC, Barreto-Alcoba M · Journal of the American Dietetic Association · 2005

Adverse event report with product analysisVerified from abstract
Open original source

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Editorial history and review method

Revision 4 · Approved for publication · Codex (publication approval explicitly authorized by site owner; category migration)

Prepared and checked with AI. Publication approval does not imply independent expert review. Request a correction.

Applied the group-1 audit. long-term-glycaemic-control was factually wrong: the headline said nothing tests whether regular vinegar changes long-term glucose control, when meta-analyses of 8-12+ week randomised vinegar trials and an 8-week randomised trial exist. It is rewritten around Siddiqui 2018 (HbA1c -0.39 percentage points, 95% CI -0.59 to -0.18, I2 = 0%), Cheng 2020 (6 studies, 317 patients), Hadi 2021 (HbA1c -0.50, I2 = 91%), Arjmandfard 2025 (HbA1c -1.53, insulin +2.06 microU/mL), Tehrani 2025 (HbA1c -0.91, I2 = 98.9%) and Jafarirad 2023 (8 weeks, 30 mL/day, insulin and HOMA-IR rising in the vinegar arm), with evidenceBasis changed from Indirect evidence to Randomized intervention. Seven sources were added and cited. The verdict no longer says no long-term evidence exists. Implementation item 1 now separates Johnston's ~10 g acetic acid dose from the 20-30 mL/day used in the HbA1c trials; a fourth precaution records the adverse-direction insulin and HOMA-IR result; the satiety headline, truncated mid-word at 220 characters, was completed. Hill 2005 is cited for the existing tablet and oesophageal-injury precaution. Second reviewer must re-check: (a) whether these low-quality, mutually overlapping HbA1c meta-analyses should be carried at all, or whether the entry should be re-scoped to acute effects with an explicit acknowledgement; (b) that the hypoglycaemia precaution remains a reasoned inference from glucose lowering rather than trial adverse-event data, which is still not disclosed to the reader; (c) that the Tehrani 2025 record states its HbA1c unit as mg/dl, which is almost certainly a typographical error in the source and is transcribed as printed. Publication release 2026-10-04: site owner authorized a bounded AI audit and release of this exact revision. See docs/release-audit-2026-10-04.md for source-check findings and limits. No independent health-professional or peer review is claimed. Category migration 2026-10-04: removed the separate goals field; categories: Nutrition, Long-term health → Nutrition, Long-term health. Research assessments, sources, guidance, precautions, and evidence review dates are unchanged. This revision awaits publication approval; no new evidence review is claimed. Publication approval 2026-10-04: site owner explicitly accepted all current category-migration revisions for deployment and requested that remaining limitations be retained in docs/content-review-backlog.md. Approval applies to this exact content revision. No new evidence review, independent expert review, or clinical validation is claimed; existing precautions and disclosures remain in effect.