Vitamin C (Ascorbic acid) (VITC)

Vitamin C, or ascorbic acid, is a water-soluble vitamin that is essential for numerous physiological processes. Since the human body cannot synthesize or store it in significant amounts, regular dietary intake is necessary.

Functions in the Body

• Antioxidant Protection
  Scavenges free radicals, reducing oxidative stress and preventing cellular damage.
• Collagen Synthesis
  Cofactor for prolyl and lysyl hydroxylases, enzymes that stabilize collagen strands. Collagen is critical for:
  • Healthy skin (wound healing, elasticity)
  • Blood vessel integrity (capillary strength)
  • Bone and cartilage formation
• Immune Support
  • Enhances neutrophil function and phagocytosis
  • Promotes lymphocyte proliferation
  • Supports differentiation of T-cells
• Iron Absorption
  Converts dietary non-heme iron (plant sources) into a more absorbable ferrous form, helping prevent iron-deficiency anemia.
• Neurotransmitter Synthesis
  Involved in the biosynthesis of norepinephrine and serotonin, supporting mood and cognitive function.
• Wound Healing & Tissue Repair
  Through collagen formation, accelerates recovery from injuries and reduces scar formation.

Symptoms of Deficiency

Vitamin C deficiency typically develops over weeks to months of inadequate intake.

1. Early Signs
   • Fatigue and malaise
   • Weakness and irritability
2. Progressive Deficiency
   • Scurvy:
     • Swollen, bleeding gums and gingivitis
     • Ecchymoses and petechiae (skin bruising)
     • Impaired wound healing and reopening of healed scars
     • Joint pain and swelling (due to weakened connective tissue)
   • Anemia:
     • Microcytic or normocytic anemia from reduced iron absorption
3. Advanced Deficiency
   • Corkscrew hair (twisted, coiled hair shafts)
   • Tooth loss (periodontal breakdown)
   • Severe fatigue, depression, and psychological disturbances

Symptoms of Overdose (Hypervitaminosis C)

Since Vitamin C is water-soluble, excess intake is usually excreted in urine. However, chronic high-dose supplementation (> 2,000 mg/day) can cause:

• Gastrointestinal Distress
  • Nausea, abdominal cramps
  • Diarrhea or loose stools
• Increased Kidney Stone Risk
  • Oxalate stone formation in susceptible individuals (especially with a history of renal calculi)
• Other Possible Effects
  • Headache and insomnia at very high doses
  • Hemolysis in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency

Diagnosis

1. Plasma Ascorbic Acid Level
   • Deficiency: < 11 µmol/L
   • Marginal: 11–23 µmol/L
   • Adequate: 23–85 µmol/L
   • High: > 85 µmol/L (usually from supplementation)
2. Clinical Evaluation
   • Review dietary history (low fruit/vegetable consumption)
   • Physical examination for gingival changes, bruising, and poor wound healing
3. Additional Laboratory Tests
   • Complete Blood Count (CBC) to check for anemia
   • Iron studies (serum ferritin, transferrin saturation) if suspicion of iron-deficiency anemia

Dietary Sources

Food Source	Approximate Vitamin C per Serving
Red Bell Pepper (1 cup)	190 mg
Orange (1 medium)	70 mg
Kiwi (1 medium)	70 mg
Strawberries (1 cup)	85 mg
Broccoli (½ cup, cooked)	50 mg
Brussels Sprouts (½ cup)	50 mg
Papaya (½ cup)	45 mg
Tomatoes (1 medium)	20 mg
Spinach (½ cup, cooked)	9 mg

Recommended Dietary Allowance (RDA):

• Adult Men (≥ 19 years): 90 mg/day
• Adult Women (≥ 19 years): 75 mg/day
• Pregnant Women: 85 mg/day
• Lactating Women: 120 mg/day
• Smokers: +35 mg/day (smoking increases oxidative turnover)

Prevention & Maintenance

• Balanced Diet:
  Include at least one source of Vitamin C at each meal—citrus fruits, berries, tomatoes, or cruciferous vegetables.
• Proper Food Handling:
  • Store produce in cool environments to preserve ascorbic acid.
  • Minimize cooking time and use steaming or raw preparations to reduce vitamin loss.
• Supplementation:
  • Consider 100–200 mg/day if dietary intake is insufficient or during increased needs (illness, smoking, pregnancy).
  • Avoid megadoses (> 2,000 mg/day) to prevent gastrointestinal and renal side effects.

Frequently Asked Questions (FAQs)

1. What are the primary benefits of Vitamin C?
   • Enhances collagen formation, antioxidant defense, immune function, and iron absorption.
2. Can I get enough Vitamin C from food alone?
   • Yes. A varied diet with fruits and vegetables typically meets RDA levels. For example, a single cup of strawberries (85 mg) plus a red bell pepper (190 mg) far exceed daily requirements.
3. Is supplementation necessary?
   • Not for most healthy adults with adequate dietary intake. Supplements may be recommended for individuals with malabsorption syndromes, smokers, the elderly, or those on restrictive diets.
4. How much Vitamin C do I need daily?
   • Adults (Men): 90 mg, Adults (Women): 75 mg. Smokers require an additional 35 mg due to increased oxidative turnover.
5. Can Vitamin C prevent or treat the common cold?
   • Evidence suggests regular Vitamin C may slightly reduce the duration and severity of colds in some individuals, but it does not reliably prevent the cold itself.

Key Takeaways

• Early Recognition: Watch for signs of scurvy—especially in populations with limited access to fresh produce.
• Balanced Intake: Prioritize whole-food sources (fruits/vegetables) before relying on high-dose supplements.
• Safe Supplementation: Keep supplemental doses below the Tolerable Upper Intake Level (UL) of 2,000 mg/day to avoid gastrointestinal upset and kidney stone risk.
• Clinical Monitoring: If you suspect deficiency (fatigue, bruising, poor wound healing), measure plasma ascorbic acid and consider dietary recall.

Ensuring adequate Vitamin C intake through diet (or supplements when necessary) is vital for overall health, immune resilience, and prevention of deficiency-related disorders.