Apple Cider Vinegar | Supplementopedia

Overview

Apple cider vinegar (ACV) is a fermented liquid.
It is derived from the enzymatic conversion of apple sugars into ethanol and then into acetic acid (the primary active constituent) by Acetobacter species.
In the supplement world, it is marketed primarily as a functional food ingredient.
It may influence metabolic and gastrointestinal processes.

Post-prandial Glucose: ACV modestly improves post‑prandial glucose excursions (≈ 5–10 % reduction).
Insulin Sensitivity: It may enhance insulin sensitivity in overweight adults (Kondo et al., 2009).
Blood Pressure: Small‑scale studies report reductions in systolic blood pressure (≈ 3 mm Hg).
Weight Loss: Modest weight‑loss effects (≈ 0.5 kg/week) have been observed when combined with a hypocaloric diet.
Antimicrobial Activity: Acetic acid exhibits antimicrobial activity against E. coli and S. aureus in vitro, supporting its use as a food‑preservative.
Satiety: Limited data suggest a modest increase in satiety hormones (e.g., GLP‑1) after ACV ingestion, potentially aiding appetite control.
Antioxidant/Anti-inflammatory: Preliminary animal work suggests antioxidant and anti-inflammatory effects via modulation of NF‑κB, though human data remain sparse.
Limitations: Claims regarding cognitive or extensive physical performance benefits lack robust support.
Strongest Data: ACV’s strongest data pertain to glycemic regulation and modest cardiovascular risk‑factor modulation.

Gastric pH: The primary bioactive component, acetic acid (CH₃COOH), lowers gastric pH.
Mineral Absorption: This enhances the solubility and absorption of minerals (e.g., calcium, magnesium).
Hepatic Effects: In the liver, acetic acid is converted to acetyl‑CoA, entering the citric‑acid cycle and increasing hepatic fatty‑acid oxidation, which can blunt post‑prandial lipogenesis.
AMPK Activation: Acetic acid activates the AMP‑activated protein kinase (AMPK) pathway.
Glucose Uptake: This increases glucose uptake in skeletal muscle.
Gluconeogenesis Suppression: It suppresses hepatic gluconeogenesis.
Carbohydrate Digestion: The vinegar’s organic acids (malic, citric) and polyphenols (e.g., catechin, quercetin) may inhibit α‑glucosidase and α‑amylase, slowing carbohydrate digestion.
GLP-1 Secretion: Acetic acid stimulates the vagus nerve and enteroendocrine cells, augmenting glucagon‑like peptide‑1 (GLP‑1) secretion, which contributes to the observed insulin‑sensitizing effect.
Antimicrobial Action: Antimicrobial activity arises from the low pH and disruption of bacterial cell‑membrane integrity, limiting pathogen growth in the gastrointestinal tract.

Clinical Trials: Most clinical trials employ 1–2 × 15 mL (≈ 1–2 Tbsp) of liquid ACV diluted in ≥ 200 mL of water, taken 20–30 min before meals, providing 1–2 g of acetic acid per dose.
Capsule/Powder: For capsule or powder formulations, the typical range is 500 mg–1 g of standardized acetic‑acid equivalents per day, split into two doses (pre-breakfast and pre-dinner).
Glycemic Control: For glycemic control, a single dose of 10‑15 mL before a carbohydrate‑rich meal is common.
Weight Management: For weight‑management protocols, 2 × 15 mL daily is often recommended.
Gastrointestinal Sensitivity: Users with gastrointestinal sensitivity may start with 5 mL (½ Tbsp) and titrate upward.
Athletes: Athletes seeking potential performance benefits should limit intake to ≤ 30 mL daily to avoid excessive acidity.
General Advice: Always follow product-specific instructions; avoid exceeding 30 mL/day unless under professional supervision.

General Safety: ACV is generally safe when diluted.
Common Side Effects: Common side effects include gastrointestinal irritation, nausea, and reflux due to its acidity.
Chronic High-Dose: Chronic high‑dose exposure can cause dental enamel erosion and esophageal mucosal irritation.
Kidney: In the kidney, excessive acetic acid may exacerbate nephrolithiasis by increasing urinary calcium and oxalate excretion.
Drug Interactions: Drug interactions include potentiation of potassium‑wasting diuretics (e.g., furosemide) and possible additive hypoglycemic effects with insulin or sulfonylureas, increasing hypoglycemia risk.
At-Risk Populations: Populations at risk—individuals with gastroparesis, peptic ulcer disease, or chronic kidney disease—should avoid or limit ACV.
Pregnancy/Lactation/Children: Pregnant or lactating women, and children, lack sufficient safety data for high‑dose supplementation; modest culinary use is considered acceptable.
When to Seek Medical Advice: Discontinue use and seek medical advice if persistent abdominal pain, dysphagia, or electrolyte disturbances develop.

Principal Chemical: Apple cider vinegar's principal chemical is acetic acid (ethanoic acid, IUPAC: ethanoic acid), molecular formula C₂H₄O₂, with a molar mass of 60.05 g mol⁻¹.
Acetic Acid Properties: Acetic acid is a small, polar, weak acid (pKa ≈ 4.76) that dissociates to acetate (CH₃COO⁻) in solution.
Other Acids: Additional organic acids include malic acid (C₄H₆O₅) and citric acid (C₆H₈O₇), contributing to the overall acidity (pH ≈ 2.5–3.0).
Polyphenols: Polyphenols such as catechin (C₁₅H₁₄O₆) and quercetin (C₁₅H₁₀O₇) are present in trace amounts, providing antioxidant capacity.
Other Components: The vinegar’s viscosity and aroma are contributed by volatile esters (e.g., ethyl acetate) and aldehydes (e.g., acetaldehyde).
Supplement Formulations: In supplement formulations, the acetic‑acid content is often standardized to 5–10 % w/v, with the remainder comprising water, residual sugars, and micronutrients.

Production: Commercial ACV is produced by crushing apples (typically Malus domestica) and fermenting the juice.
Fermentation Stages: First, yeast converts sugars to ethanol; then Acetobacter spp. oxidize ethanol to acetic acid in a two‑stage fermentation (alcoholic → acetic).
Quality Products: Quality‑grade products are “unfiltered” (containing the “mother” of cellulose and yeast) and “organic” with minimal pesticide residues.
Supplement Production: For supplements, ACV is often produced via controlled fermentation in stainless‑steel bioreactors to ensure consistent acidity (5–7 % acetic acid).
Processing: Filtration removes the “mother” for clear liquids; freeze‑drying or spray‑drying yields powdered extracts standardized to a specific % of acetic acid.
Quality Considerations: Quality considerations include verification of acetic‑acid content by titration, absence of heavy metals, and compliance with USP/FAO/WHO guidelines for food‑grade vinegar.