Regulatory approvals for ascorbic acid
Food and beverage industry
The US FDA classifies it as Generally Recognized as Safe (GRAS) for use as a food additive and preservative.
European Food Safety Authority (EFSA): Approved under food additive code E300.
Codex Alimentarius: Considered an effective antioxidant for food applications.
Pharmaceutical and nutritional uses
FDA-approved for treating Vitamin C deficiency (scurvy) and as a significant element in dietary supplements.
World Health Organization (WHO): Included on the Essential Medicines List (EML) for its ability to cure scurvy and enhance iron absorption.
European Medicines Agency (EMA): Approved for oral and injectable medicinal formulations.
Cosmetic and Skincare Applications
FDA and EU Regulations: Cosmetic formulations are permitted because of their antioxidant capabilities, which help protect the skin from aging and environmental harm.
PHARMACOKINETICS:
Absorption
Primarily absorbed in the small intestine via active transport and passive diffusion
Bioavailability:
High at low doses (~70-90% for 30-180 mg/day).
Decreases with higher doses (>1g/day) as absorption saturates.
Excess is excreted in urine.
Distribution
Free ascorbic acid is the primary form in which it circulates in the bloodstream.
High-demand organs, such as the brain, adrenal glands, liver, and leukocytes, actively absorb tissue.
Storage There is no considerable long-term storage; any excess is promptly eliminated.
Metabolism
DHA is mostly metabolized in the liver and can be converted back into ascorbic acid or further broken down.
Metabolized into oxalic and diketogulonic acids, which are eliminated in urine.
Excretion
Kidneys expel primarily through urine.
Renal reabsorption occurs through SVCT1 transporters.
Excess quantities (>1g) are quickly removed without metabolization.
High doses may increase oxalate levels and cause renal stones in predisposed persons.
DOSAGE AND ADMINISTRATION
Adults: The recommended daily allowance (RDA) for vitamin C is 90 mg/day for men and 75 mg/day for women. Smokers may require an additional 35 mg/day.
Children: 1-3 years: 15 mg/day, 4-8 years: 25 mg/day, 9-13 years: 45 mg/day, 14-18 years: 75 mg/day (boys) / 65 mg/day (girls)
For Treatment of Scurvy (Severe Vitamin C Deficiency)
Adults: High doses are typically required, often starting with 300-1,000 mg per day until symptoms improve.
Children: Doses are adjusted based on age and severity, typically 100 mg per day.
DRUG INTERACTIONS
Iron Supplements: Enhances absorption of non-heme iron.
Anticoagulants (e.g., Warfarin): May reduce anticoagulant effects.
Chemotherapy Drugs: High doses may interfere with efficacy.
Oral Contraceptives: May reduce vitamin C levels.
Statins: Could potentially reduce cholesterol-lowering effects.
Barbiturates: Can lower vitamin C levels.
Corticosteroids: May increase the risk of deficiency.
Alcohol: Increases risk of deficiency.
Antacids: May reduce absorption when taken together.
NSAIDs: Increased risk of kidney damage.
CONTRAINDICATIONS
Contraindications of Ascorbic Acid:
Hypersensitivity: Allergy to ascorbic acid or components.
Kidney Stones: Risk of stone formation with high doses.
Iron Overload Disorders: (e.g., Hemochromatosis, Thalassemia) – increases iron absorption.
G6PD Deficiency: High doses may cause hemolysis.
Severe Renal Impairment: Risk of accumulation in kidney dysfunction
SIDE EFFECTS
Common Side Effects:
Upset Stomach: Nausea, abdominal cramps, and diarrhea (especially with high doses).
Heartburn: Acidic nature may cause irritation.
Headache: Some people may experience headaches.
Severe Side Effects:
Kidney Stones: High doses (over 2,000 mg/day) can increase the risk.
Gastrointestinal Issues: Severe abdominal pain, bloating, and diarrhea.
Hemolysis: In people with G6PD deficiency, high doses can cause red blood cell destruction.
TOXICITY
Symptoms:
Gastrointestinal issues (diarrhea, nausea, cramps)
Kidney stones (especially in high doses)
Iron overload (in iron-sensitive individuals)
Hemolysis (in G6PD deficiency)
Risk of kidney damage with prolonged high doses
