Does apple cider vinegar actually improve digestion?
The short answer is yes, but the improvements are modest and mostly reported in people with overweight or obesity. In a 30-day observational study of 45 overweight adults, daily consumption of an ACV effervescent tablet led to self-reported improvements in digestion, appetite, constipation, cravings, and gas problems [2]. A larger 60-day randomized controlled trial with 77 participants confirmed these findings, showing that the ACV group experienced significant reductions in digestive issues compared to the control group, who only followed diet and exercise [4]. Both studies reported an average weight loss of about 1.5 kg (3.3 lbs) and a 1 cm reduction in waist circumference over 30 days [2], suggesting that digestive benefits may be linked to weight management.
How does ACV affect gut bacteria?
Animal studies provide the strongest evidence that ACV can positively alter the gut microbiome. In a 2025 study on mice fed a high-fat diet, apple cider vinegar powder (ACVP) restored gut microbiota diversity, increasing beneficial bacteria like Muribaculaceae and Akkermansia, while reducing harmful bacteria linked to inflammation [3]. This led to a 26.3% reduction in weight gain and a 48% drop in liver enzyme ALT, indicating reduced liver injury [3]. Similarly, a 2023 study on normal mice found that vinegar consumption increased Verrucomicrobia and Akkermansia, which are associated with anti-inflammatory effects and improved immune function [7]. However, a 2021 study on human skin microbiome found that dilute ACV soaks did not alter bacterial composition in people with atopic dermatitis [6], highlighting that effects may be specific to the gut and depend on concentration and delivery method.
Does ACV help with blood sugar and overall health?
Yes, ACV appears to improve blood sugar control, which indirectly supports gut health by reducing metabolic stress. In a 12-week study of 70 type 2 diabetes patients, those who consumed 30 ml of ACV daily had significant reductions in fasting plasma glucose (FPG) and HbA1c (a measure of long-term blood sugar) compared to the control group [5]. The improvements were statistically significant (p<0.001) [5]. Additionally, a 2021 study on fish found that ACV increased digestive enzyme activity (amylase, lipase, protease) and improved immune function [1], suggesting potential benefits for nutrient absorption. However, these findings are from animal or small human studies, and more research is needed to confirm effects in healthy adults.
About These Sources
This answer is built on 7 peer-reviewed studies — published from 2021 to 2025, 4 from 2024 or later, 2 in Q1 journals — selected as the most relevant from 9 studies that passed quality screening, drawn from 44 papers retrieved from a database of over 500 million.
Sources used in this answer
Improvement of non-specific immunity, growth, and activity of digestive enzymes in Carassius auratus as a result of apple cider vinegar administration to diet.
In a 105-day fish study, apple cider vinegar (2% in diet) significantly increased digestive enzyme activity (amylase, lipase, protease) and improved immune markers like lysozyme and immunoglobulin in skin mucus and serum [1].
Apple Cider Vinegar Effervescent Tablets on Gut Health, Obesity and User Experience: An Observation
In a 30-day observational study of 45 overweight adults, daily ACV effervescent tablets led to self-reported improvements in digestion, appetite, constipation, cravings, and gas problems, along with an average weight loss of 1.46 kg and 1.13 cm reduction in waist circumference [2].
Apple Cider Vinegar Powder Mitigates Liver Injury in High-Fat-Diet Mice via Gut Microbiota and Metabolome Remodeling
In a 12-week mouse study, apple cider vinegar powder reduced high-fat-diet-induced weight gain by 26.3%, lowered liver enzymes ALT by 48% and AST by 21.5%, and restored gut microbiota diversity by increasing Muribaculaceae and Akkermansia [4].
Apple cider vinegar effervescent tablets on gut health, obesity and user experience – A randomized controlled trial
In a 60-day randomized controlled trial of 77 overweight adults, daily ACV effervescent tablets significantly reduced weight, BMI, waist and hip circumference, and improved digestive issues like appetite, constipation, cravings, and gas problems compared to diet and exercise alone [5].
Effects of Apple Cider Vinegar on Glycemic Status in Type 2 Diabetes Mellitus
In a 12-week interventional study of 70 type 2 diabetes patients, 30 ml/day of ACV significantly reduced fasting plasma glucose and HbA1c levels compared to the control group (p<0.001) [6].
Apple cider vinegar soaks do not alter the skin bacterial microbiome in atopic dermatitis.
In a 14-day split-arm pilot study of 11 atopic dermatitis patients and 11 healthy controls, daily 0.5% ACV soaks did not significantly alter skin bacterial microbiome composition or reduce Staphylococcus aureus abundance [8].
Beneficial effect of vinegar consumption associated with regulating gut microbiome and metabolome
In a mouse study, Shanxi aged vinegar consumption significantly decreased inflammatory factors, increased immunoglobulins and NK cells, and altered gut microbiota by upregulating Verrucomicrobia and Akkermansia while downregulating Firmicutes [9].