Apple Cider Vinegar and Blood Sugar: What the Studies Say

|Damian Rayne
Apple Cider Vinegar and Blood Sugar: What the Studies Say

TL;DR

  • There is no authorised health claim in Great Britain for vinegar, apple cider vinegar or acetic acid. This article reports published research and is not medical advice.
  • In small, short trials, vinegar taken with a starchy meal lowered the rise in blood sugar and insulin over the next hour or two.
  • The effect was modest. The trials were small and brief, and they used different vinegars, doses and meals.
  • The doses were ordinary table vinegar, about 2 tsp (10 ml) to 2 tbsp (30 ml), taken with the meal, just before it, or at bedtime.
  • No trial tested a "10 to 15 minutes before eating" window, and none tested a canned drink.

Does apple cider vinegar lower blood sugar? A little, in small trials, and only in a narrow way. When people drank vinegar with a starchy meal, the rise in their blood sugar over the next hour or two was smaller than when they ate the same meal without it. That is the finding: what follows is what it covers, what it does not, and where the research stops.

This article is general information about published research on vinegar. It is not medical advice, and it does not describe what any drink sold on this site does. There is no authorised health claim in Great Britain for vinegar, apple cider vinegar or acetic acid. If you have a medical condition or take any medicine, speak to a GP or pharmacist before changing your diet.

Does apple cider vinegar lower blood sugar?

In the trials so far, yes, a little, and only for the couple of hours after a meal. Nobody has shown more than that.

The clearest overview comes from Shishehbor and colleagues, who in 2017 pooled the trials that had measured blood sugar and insulin after a meal. The pooled result was a modest reduction in the post-meal rise in both. The precise figures sit in the table below, and they come with a caveat: the trials disagreed with each other, and the range around the average is wide. Pooled results like this come out as a standardised score rather than a reading you could see on a glucose meter, so the fair translation is "a smaller rise, on average".

The most quoted trial of all is older and smaller. In 2004, Johnston, Kim and Buller gave 29 adults a drink of vinegar in water two minutes before a breakfast of bagel, butter and orange juice. Some were insulin resistant, ten had type 2 diabetes, and the rest had neither. Insulin sensitivity, a measure of how well the body responds to its own insulin, was 34% higher in the insulin-resistant group after vinegar than after the placebo drink, and the change in the type 2 diabetes group was smaller and could have been chance.

That was one meal, in 29 people, written up as a two-page letter rather than a full paper: a signal, not a settled result. If you are managing a diagnosed condition, the people to ask are your GP or your diabetes team, not a blog.

What does apple cider vinegar do to blood sugar?

The leading idea is simple. Acetic acid, the sour part of vinegar, appears to slow the digestion of starch, so sugar reaches the blood more gradually. Laboratory work supports that. Nobody has confirmed it in people.

Apple cider vinegar is fermented apple juice. Yeasts turn the sugar in the juice into alcohol, then bacteria turn that alcohol into acetic acid, which is what makes any vinegar sharp. Cider vinegar runs at about 5% to 6% acetic acid, much like wine vinegar (Johnston and Gaas, 2006). We look at how it differs from the clear stuff in the cupboard in apple cider vinegar vs white vinegar.

Postprandial glucose is the technical name for blood sugar after a meal. Researchers rarely record a single peak. They measure the area under the curve, which you can picture as the total amount of time your blood sugar spends above where it started.

A glucose spike is the everyday word for a quick rise and fall. It has no agreed clinical cut-off, and none of these studies measured spikes as such.

Take the enzyme idea first. In laboratory work reviewed by Johnston and Gaas (2006), acetic acid slowed sucrase, lactase and maltase, the enzymes that break sugars down into a form the gut can absorb. Slower breakdown would mean slower absorption. This is bench science rather than a measurement taken in a person, so treat it as a lead rather than a conclusion.

The second idea is that vinegar slows how fast the stomach empties, and the evidence there cuts both ways. Hlebowicz and colleagues (2007) gave vinegar in water each morning for a fortnight to ten people with type 1 diabetes and gastroparesis, a complication that already leaves the stomach slow to empty. Vinegar slowed it further still, and the authors thought that might work against blood sugar control in that group rather than for it. In healthy volunteers eating bread, a study noted in the same review found no change in emptying at all.

Johnston's group added two useful blanks in 2010. Sodium acetate, the salt form of the same acid, did nothing to post-meal blood sugar. Nor did vinegar, when the test meal was simple sugar rather than starch. Both point back to starch digestion as the place where anything happens.

What did the studies actually test?

Single test meals, mostly, in small groups of volunteers, using ordinary table vinegar measured out by the gram or the millilitre. These are the trials this article draws on, with their numbers. The mechanism and safety studies are in the Sources list.

Study Year Who took part Vinegar dose Timing What was reported Link
Östman et al., Eur J Clin Nutr 2005 12 healthy volunteers 18, 23 and 28 mmol acetic acid Served with a white bread breakfast (50 g carbohydrate) The highest dose lowered the glucose response at 30 and 45 min and insulin at 15 and 30 min; "a significant dose-response relation was seen at 30 min for blood glucose and serum insulin responses" Journal
Johnston, Kim & Buller, Diabetes Care 2004 29 adults: 8 insulin sensitive, 11 insulin resistant, 10 with type 2 diabetes 20 g apple cider vinegar in 40 g water 2 minutes before a bagel, butter and orange juice meal (87 g carbohydrate) Insulin sensitivity over the next 60 min 34% higher in the insulin-resistant group (p = 0.01); 19% higher, not significant, in the type 2 diabetes group (p = 0.07) Journal
White & Johnston, Diabetes Care 2007 11 adults with well-controlled type 2 diabetes (4 men, 7 women, aged 40–72) 2 tbsp (30 ml) apple cider vinegar with about 28 g (1 oz) of cheese At bedtime Waking glucose fell 0.26 mmol/L (4%) after vinegar and 0.15 mmol/L (2%) after placebo (p = 0.033) Journal
Liatis et al., Eur J Clin Nutr 2010 16 people with type 2 diabetes, in two matched groups Not stated in the accessible abstract Added to the meal Glucose iAUC 181±78 vs 311±124 mmol·min/L with a high-GI meal (p = 0.04); no effect with a low-GI meal (p = 0.56) Journal
Johnston et al., Ann Nutr Metab 2010 9 to 10 adults per trial, four crossover trials, with and without type 2 diabetes 10 g and 20 g During the meal, against 5 hours before it "Two teaspoons of vinegar (10 g) effectively reduced PPG", most pronounced at mealtime; vinegar "attenuated PPG by ∼20% compared to placebo" Journal
Johnston et al., Ann Nutr Metab 2010 9 to 10 adults Sodium acetate (an acetate salt) During the meal "sodium acetate did not alter PPG, indicating that acetate salts lack antiglycemic properties" Journal
Johnston et al., Ann Nutr Metab 2010 9 to 10 adults 10 g and 20 g With a dextrose (simple sugar) test meal "Vinegar did not alter PPG when ingested with monosaccharides" Journal
Shishehbor et al., Diabetes Res Clin Pract 2017 Meta-analysis of clinical trials Varied by trial Varied by trial Glucose AUC SMD −0.60 (95% CI −1.08 to −0.11, p = 0.01); insulin AUC SMD −1.30 (95% CI −1.98 to −0.62, p < 0.001) PubMed

Liatis and colleagues found an effect when vinegar went with a high-GI meal of mashed potato, and none at all with a low-GI meal, which suggests the meal does more of the work than the vinegar does. Nothing here runs long, either: no trial follows anyone for years, and none measures more than a blood test.

Does apple cider vinegar before meals lower blood sugar?

With the meal beat before the meal, in the one trial that compared the two directly. Johnston's group tried two teaspoons of vinegar at mealtime and the same amount five hours earlier. Mealtime came out ahead, cutting the rise in blood sugar afterwards by about a fifth compared with a placebo.

The other trials sit close to the meal as well. Johnston, Kim and Buller gave theirs two minutes before the food. Liatis added it to the plate. White and Johnston (2007) gave it at bedtime with a small piece of cheese and measured blood sugar on waking, which is a different question altogether.

You will see "10 to 15 minutes before eating" repeated widely online. No trial in this evidence base tested that interval. The closest anyone came was those two minutes in 2004, and the only head-to-head comparison ran mealtime against five hours earlier. Timing after a meal and the morning routine have their own articles: apple cider vinegar after meals and drinking apple cider vinegar in the morning.

Can apple cider vinegar raise blood sugar?

Plain vinegar has almost nothing in it that could. Sweetened vinegar products are another matter.

Making vinegar uses the sugar up. Yeasts eat it, alcohol follows, then acid, and what is left is sharp rather than sweet. Products built around vinegar are a different story: some gummies and drinks carry added sugar, so the "of which sugars" line is the one to read.

Anything that blends vinegar with fruit juice brings the juice's sugars along with it. The NHS counts those, together with sugars added to food and drink and the sugars in honey and syrups, as free sugars, and says adults should have no more than 30 g of free sugars a day, roughly seven sugar cubes.

So read the panel rather than the front of the pack: the sugars per 100 ml, the carbohydrate line as well, and the serving size the label is using.

Who should be careful with apple cider vinegar?

Anyone on prescription medicine, anyone with a stomach condition, and anyone who has been told their potassium is low.

Mayo Clinic warns that vinegar can interfere with some medicines, naming the diuretics used for blood pressure and insulin, because potassium can fall as a result. Cleveland Clinic adds laxatives to that list, and says to avoid vinegar if your potassium is already low. RxList notes that the same drop in potassium can worsen the side effects of digoxin. None of that makes a salad dressing dangerous, but if you take any of those medicines, the conversation to have is with your pharmacist.

Very large amounts, taken for years, are a different matter. A case report in Nephron described a woman in her twenties with low potassium who had been getting through about 250 ml of cider vinegar a day for six years, in water and on her food (Lhotta and colleagues, 1998). That is on another scale from the two teaspoons to two tablespoons the trials used.

Vinegar is also hard on the stomach for some people. In the gastroparesis study above it slowed an already slow stomach further. In a small tolerance study in people with type 2 diabetes, around half of those taking vinegar reported a side effect over six weeks, against about one in nine of the comparison group (Johnston and colleagues, 2008). Reflux, wind and changes in bowel habits were the usual complaints.

It is harder still on teeth. In an eight-week trial, people drinking two tablespoons of vinegar in a cup of water twice a day saw their tooth-wear scores rise by 18%, while the comparison group's did not move (Anderson and colleagues, 2021). The Oral Health Foundation lists vinegar among the acidic causes of dental erosion, alongside fizzy drinks, "including diet and sugar-free versions". Its advice for anything acidic is worth following:

  • "Limit acidic foods and drinks to mealtimes."
  • "Use a straw to reduce contact with the teeth."
  • "Swallow drinks quickly rather than holding them in your mouth."
  • "Wait at least one hour after eating or drinking before brushing your teeth."
  • "Finish meals with milk or cheese to help neutralise acid."

Do not drink it neat. A Dutch dental journal reported the case of a 15-year-old girl whose eroded teeth were traced back to a daily glass of apple cider vinegar (Gambon and colleagues, 2012). Cleveland Clinic suggests a tablespoon in a mug of warm water, and notes there is no standard dose anyway. More in apple cider vinegar side effects.

Common questions

Do the studies show apple cider vinegar "balances" or "controls" blood sugar?

The studies here measured glucose and insulin after test meals, or waking glucose after a few days. None tested "balancing" or "controlling" blood sugar in the everyday sense, and none was a treatment trial.

How much vinegar did the studies use?

Between about 10 g and 30 ml, which is two teaspoons to two tablespoons of ordinary table vinegar. In Johnston's 2010 trials, two teaspoons (10 g) taken with the meal was enough to change the measurement.

Should I use apple cider vinegar instead of medicine I have been prescribed?

No. As diabetes.co.uk, a site run by Diabetes Digital Media rather than the Diabetes UK charity, puts it: "ACV is not a replacement for medications." If your blood sugar is worrying you, your GP or pharmacist is the person to ask.

Is a sparkling apple cider vinegar drink the same as the vinegar used in the studies?

No. Those trials used table vinegar, measured by the gram or millilitre and taken in water or with food. A canned apple cider vinegar drink is a soft drink, not a supplement and not a medicine, and no trial here tested a canned drink of any kind.

About ApealWörld. ApealWörld makes organic sparkling soft drinks in cans, made with 4.5% organic apple cider vinegar and botanicals. There are three: Activate (lemon and mint), Defence (organic ginger) and Metabolism (cinnamon, clove and vanilla), plus a Starter Pack with all three. Each can lists sugars at less than 0.1 g per 100 ml (labelled zero sugar) and 5.2 g of carbohydrate per 100 ml, with no artificial sweeteners and no artificial preservatives. The drinks are pasteurised and are not sold as a source of live cultures. The range is certified organic by the Soil Association and holds a Great Taste 2024 award. Shop the range, or read more on the Learn about ACV page.

Sources

  1. Shishehbor F, Mansoori A, Shirani F. "Vinegar consumption can attenuate postprandial glucose and insulin responses; a systematic review and meta-analysis of clinical trials." Diabetes Research and Clinical Practice. 2017;127:1–9. PMID 28292654. https://pubmed.ncbi.nlm.nih.gov/28292654/
  2. Johnston CS, Kim CM, Buller AJ. "Vinegar improves insulin sensitivity to a high-carbohydrate meal in subjects with insulin resistance or type 2 diabetes." Diabetes Care. 2004;27(1):281–282. PMID 14694010. https://diabetesjournals.org/care/article/27/1/281/26582/Vinegar-Improves-Insulin-Sensitivity-to-a-High
  3. Östman E, Granfeldt Y, Persson L, Björck I. "Vinegar supplementation lowers glucose and insulin responses and increases satiety after a bread meal in healthy subjects." European Journal of Clinical Nutrition. 2005;59(9):983–988. PMID 16015276. https://www.nature.com/articles/1602197
  4. White AM, Johnston CS. "Vinegar ingestion at bedtime moderates waking glucose concentrations in adults with well-controlled type 2 diabetes." Diabetes Care. 2007;30(11):2814–2815. PMID 17712024. https://diabetesjournals.org/care/article/30/11/2814/4824/Vinegar-Ingestion-at-Bedtime-Moderates-Waking
  5. Liatis S, Grammatikou S, Poulia KA, et al. "Vinegar reduces postprandial hyperglycaemia in patients with type II diabetes when added to a high, but not to a low, glycaemic index meal." European Journal of Clinical Nutrition. 2010;64(7):727–732. PMID 20502468. https://www.nature.com/articles/ejcn201089
  6. Johnston CS, Steplewska I, Long CA, Harris LN, Ryals RH. "Examination of the antiglycemic properties of vinegar in healthy adults." Annals of Nutrition and Metabolism. 2010;56(1):74–79. PMID 20068289. https://karger.com/anm/article-abstract/56/1/74/40516/Examination-of-the-Antiglycemic-Properties-of
  7. Johnston CS, Gaas CA. "Vinegar: medicinal uses and antiglycemic effect." MedGenMed. 2006;8(2):61. PMID 16926800. https://pmc.ncbi.nlm.nih.gov/articles/PMC1785201/
  8. Hlebowicz J, Darwiche G, Björgell O, Almér LO. "Effect of apple cider vinegar on delayed gastric emptying in patients with type 1 diabetes mellitus: a pilot study." BMC Gastroenterology. 2007;7:46. PMID 18093343. https://pmc.ncbi.nlm.nih.gov/articles/PMC2245945/
  9. Johnston CS, et al. (full author list not confirmed). "A preliminary evaluation of the safety and tolerance of medicinally ingested vinegar in individuals with type 2 diabetes." Journal of Medicinal Food. 2008;11(1):179–183. PMID 18361754. https://pubmed.ncbi.nlm.nih.gov/18361754/
  10. Anderson S, Gonzalez LA, Jasbi P, Johnston CS. "Evidence that daily vinegar ingestion may contribute to erosive tooth wear in adults." Journal of Medicinal Food. 2021;24(8):894–896. PMID 33297831. https://journals.sagepub.com/doi/10.1089/jmf.2020.0108
  11. Gambon DL, Brand HS, Veerman EC. "Unhealthy weight loss. Erosion by apple cider vinegar." Nederlands Tijdschrift voor Tandheelkunde. 2012;119(12):589–591. PMID 23373303. https://europepmc.org/article/MED/23373303
  12. Lhotta K, Höfle G, Gasser R, Finkenstedt G. "Hypokalemia, hyperreninemia and osteoporosis in a patient ingesting large amounts of cider vinegar." Nephron. 1998;80(2):242–243. PMID 9736833. https://karger.com/nef/article-abstract/80/2/242/209061/Hypokalemia-Hyperreninemia-and-Osteoporosis-in-a
  13. NHS. "How does sugar in our diet affect our health?" https://www.nhs.uk/live-well/eat-well/food-types/how-does-sugar-in-our-diet-affect-our-health/
  14. Office for Health Improvement and Disparities. "Great Britain Nutrition and Health Claims (NHC) register", updated 19/05/2026. https://www.gov.uk/government/publications/great-britain-nutrition-and-health-claims-nhc-register
  15. Mayo Clinic. "Apple cider vinegar for weight loss: Does it work?" https://www.mayoclinic.org/healthy-lifestyle/weight-loss/expert-answers/apple-cider-vinegar-for-weight-loss/faq-20058394
  16. Cleveland Clinic. "What apple cider vinegar can (and can't) do for you." https://health.clevelandclinic.org/exploring-the-health-benefits-of-apple-cider-vinegar
  17. RxList. "Apple cider vinegar." https://www.rxlist.com/supplements/apple_cider_vinegar.htm
  18. Oral Health Foundation. "Dental erosion." https://www.dentalhealth.org/dental-erosion
  19. diabetes.co.uk (Diabetes Digital Media). "Apple cider vinegar." https://www.diabetes.co.uk/food/apple-cider-vinegar.html