Apple Cider Vinegar Side Effects
While apple cider vinegar may offer some metabolic benefits, consumption carries documented risks including dental erosion, esophageal injury, hepatotoxicity, and gastrointestinal damage, particularly at higher doses or with prolonged use.
Documented Side Effects
Gastrointestinal and Hepatic Toxicity
The most concerning side effects involve direct tissue damage:
Esophageal injury: ACV tablets have caused esophageal burns and injury, with significant variability in product quality and pH levels across brands 1. This is particularly problematic with tablet formulations that may lodge in the esophagus.
Hepatotoxicity: A recent case report documented vinegar-induced liver damage in a 60-year-old man with long-term consumption, which resolved after discontinuation 2. This represents an uncommon but serious idiosyncratic reaction.
Gastric and intestinal damage: Animal studies at higher doses (0.51-1.02 ml/kg body weight) demonstrated erosion of gastric mucosa, dilatation of gastric glands, duodenal villus blunting, and vacuolated hepatocytes 3. These histopathological changes occurred with doses exceeding typical human consumption patterns.
Dental Erosion
Dental enamel erosion is a well-documented consequence of regular ACV consumption 4. A case report of a 15-year-old girl who consumed daily glasses of ACV for weight loss showed extensive erosive tooth wear. This practice is reportedly common in North African cultures and among bodybuilders for weight reduction purposes.
Metabolic and Hematologic Effects
Animal studies revealed dose-dependent effects 3:
- Significant reduction in weight gain at 0.51 ml/kg
- Decreased dry matter intake at higher doses
- Elevated hemoglobin, total erythrocyte counts, and total leukocyte counts
- Increased liver alkaline phosphatase activity
- Statistically significant increases in liver and spleen weight
Safety Profile Assessment
A 2020 systematic review concluded that the risk of side effects when ACV is ingested in recommended quantities and recommended ways appears inconsiderable 5. However, this assessment comes with important caveats:
- The evidence quality is insufficient due to lack of large-scale, long-term clinical studies with low risk of bias
- Most human studies have been short-term
- Product quality varies dramatically, with inconsistency in labeling, recommended dosages, and unsubstantiated health claims 1
Clinical Pitfalls to Avoid
Tablet formulations: These pose higher risk for esophageal injury and have questionable quality control. Many products tested showed doubt as to whether ACV was actually an ingredient 1.
Undiluted consumption: Direct consumption without dilution increases risk of dental erosion and gastrointestinal irritation.
High-dose or prolonged use: Doses exceeding moderate consumption levels (typically >10 mL/day) increase risk of tissue damage 3.
Weight loss use: The practice of consuming ACV for weight loss, while culturally prevalent, carries dental and gastrointestinal risks that may outweigh unproven benefits 4.
Practical Recommendations
If patients choose to consume ACV despite limited evidence for benefits:
- Use liquid form diluted in water, never tablets
- Consume through a straw to minimize dental contact
- Limit to moderate doses (<10 mL/day)
- Rinse mouth with water after consumption
- Monitor for gastrointestinal symptoms, and discontinue if they develop
- Consider liver function monitoring with prolonged use given the hepatotoxicity case report 2
- Be aware that product quality varies significantly; many commercial products lack standardization 1
The evidence suggests that while serious adverse effects are uncommon with moderate, diluted consumption, the potential for harm—particularly dental erosion and gastrointestinal injury—is real and dose-dependent, while the purported health benefits remain inadequately substantiated 5.