Vitamin C

Effects and Benefits

Core Identification

Common Names:
- Vitamin C
- Ascorbic acid
- L-ascorbic acid
- Ascorbate

Latin Name: N/A (Synthetic/naturally occurring compound; chemical formula C₆H₈O₆)

Category: Vitamin

Uses

Traditional Uses

• Scurvy prevention and treatment - British Royal Navy introduced citrus rations in the 18th century
• General health tonic - Traditional use across cultures consuming citrus fruits
• Wound healing - Historical observation that fresh fruit consumption accelerated recovery

Modern Uses

• Immune Support & Cold Prevention - Reduces duration and severity of common colds | Research quality: Strong
• Key findings: Meta-analysis of 30+ clinical trials (11,000+ participants) showed 1,000 mg daily reduced cold duration by up to 20%; five studies involving soldiers, runners, and skiers under extreme stress showed 50%+ reduction in cold risk

• Source citations: Moyad - The Supplement Handbook; Brewer - TDT Encyclopedia of Vitamins; Cochrane Database systematic review

• Antioxidant Protection - Neutralizes free radicals in body fluids | Research quality: Strong

• Key findings: Primary water-soluble antioxidant; protects cell membranes and genetic material from oxidation; regenerates vitamin E

• Source citations: Brewer - TDT Encyclopedia of Vitamins

• Collagen Synthesis - Essential for skin, bone, and connective tissue production | Research quality: Strong

• Key findings: Required for proper collagen formation; supports wound healing, skin elasticity, and bone health

• Source citations: Brewer - TDT Encyclopedia of Vitamins; Virtue - Nutrition for Intuition

• Cardiovascular Support - Supports healthy blood vessels and heart function | Research quality: Moderate

• Key findings: Study of 6,600+ people showed highest vitamin C levels associated with 27% lower coronary heart disease risk and 26% lower stroke risk; doses of 2g daily reversed impaired arterial dilation within two hours

• Source citations: Brewer - TDT Encyclopedia of Vitamins

• Iron Absorption Enhancement - Increases absorption of non-heme iron | Research quality: Strong

• Key findings: Vitamin C keeps iron in the more easily absorbed ferrous form; those taking iron supplements should combine with vitamin C

• Source citations: Brewer - TDT Encyclopedia of Vitamins; Mars - Home Reference to Holistic Health

• Pneumonia Prevention/Treatment - Supports respiratory health | Research quality: Moderate

• Key findings: Meta-analysis in Cochrane Database concluded vitamin C is beneficial in preventing and treating pneumonia; faster recovery when used with conventional medicine

• Source citations: Moyad - The Supplement Handbook

• Allergy/Hay Fever Relief - Natural antihistamine action | Research quality: Preliminary

• Key findings: Vitamin C has antihistamine action that can help reduce symptoms linked with pollen allergy
• Source citations: Brewer - TDT Encyclopedia of Vitamins; Davis - Aromatherapy A-Z

Active Compounds

Primary Active Ingredients:
- Ascorbic acid - The active form of vitamin C; powerful water-soluble antioxidant
- Dehydroascorbic acid - Oxidized form that can be converted back to ascorbic acid in the body
- Ascorbate salts - Mineral-bound forms (calcium ascorbate, sodium ascorbate) that are less acidic and may be better tolerated

Dosage Information

Standard Dosage:
- Form: Capsule, tablet, powder, or chewable
- Amount: 200-500 mg per day
- Frequency: Once or twice daily (divided doses preferred for better absorption)

Therapeutic Dosage:
- Form: Capsule, powder, or buffered tablets
- Amount: 1,000-2,000 mg per day
- Purpose: Cold/flu treatment, immune support during stress, wound healing
- Duration: Short-term use (1-2 weeks) during acute illness; longer-term at moderate doses for ongoing support

Maximum Safe Dosage:
- Daily maximum: 2,000 mg for most adults
- Warning threshold: Doses above 2,000 mg may cause GI disturbances; individuals with history of kidney stones should limit to 100 mg daily

Bioavailability Notes:
- Body tissues become saturated at doses of 120-200 mg; excess is excreted in urine
- Divided doses (smaller amounts more frequently) are better absorbed than single large doses
- Buffered and ester-C forms may be absorbed more efficiently and cause less GI upset
- Taking 5,000 mg at once provides no additional benefit as it passes through unabsorbed

How to Take It

Timing:
- Can be taken any time of day
- May be taken with or without food (with food if sensitive stomach)
- Divided doses (2-3 times daily) provide more consistent blood levels than single large doses
- During illness, doses can be increased throughout the day to "bowel tolerance"

Synergies - What It Works Well With

Complementary Supplements:
1. Bioflavonoids - Enhance vitamin C absorption and effectiveness | Combined antiviral activity; vitamin C plus bioflavonoids (1,800 mg complex) reduced cold sore duration by over half
2. Vitamin E - Vitamin C regenerates the antioxidant form of vitamin E | Combined antioxidant protection for both water-soluble and fat-soluble body compartments
3. Iron - Vitamin C dramatically increases non-heme iron absorption | Keep iron in more easily absorbed ferrous form; take iron supplements with vitamin C-rich juice
4. Zinc - Complementary immune support | Both nutrients support immune cell function and thymus gland health
5. Quercetin - Antiviral bioflavonoid in the vitamin C complex | Enhanced immune and antihistamine effects

Avoidance - What NOT to Combine With

Supplement Interactions:
1. Ginseng - Do not take together in the same dose | May reduce effectiveness of the herbal remedy; leave at least four hours between them

Drug Interactions:
1. Aspirin - Increases vitamin C loss through urine | May deplete vitamin C levels with regular use; consider supplementing a few hundred mg daily | Severity: Mild
2. Blood Thinners (Warfarin) - Conflicting evidence | Some older reports suggested high-dose vitamin C might affect anticoagulation; monitor if taking high doses | Severity: Mild to Moderate
3. Chemotherapy drugs - Complex interaction | Vitamin C may protect against some side effects and may enhance effectiveness of some drugs; always consult oncologist before supplementing during cancer treatment | Severity: Moderate
4. Nitroglycerin - Supportive interaction | Vitamin C (500 mg-2 g three times daily) may help prevent nitroglycerin tolerance | Severity: Beneficial

Food Interactions:
- No significant negative food interactions
- Absorption may be reduced when taken with very high-fiber meals

Safety Information

Contraindications:
- Hemochromatosis (iron overload disorder) - Vitamin C increases iron absorption
- History of calcium oxalate kidney stones - High doses (1,000+ mg daily long-term) may increase urinary oxalate
- Renal failure with defect in ascorbic acid or oxalate metabolism - Restrict to approximately 100 mg daily
- G6PD deficiency - Very high doses may cause hemolysis in susceptible individuals

Side Effects:
- Common at high doses: Diarrhea, stomach cramps, nausea (indicates "bowel tolerance" reached)
- Occasional: Heartburn or acid reflux with standard ascorbic acid (use buffered forms)
- Rare: Increased urinary oxalate with potential kidney stone risk in susceptible individuals

Long-Term Use:
- Generally safe for long-term use at doses up to 1,000 mg daily
- High-dose supplementation (1,000+ mg daily) for extended periods may increase kidney stone risk in susceptible individuals
- Do not stop high-dose supplementation abruptly - taper over several weeks to avoid "rebound scurvy" effect
- Calcium ascorbate (Ester-C) form may have reduced impact on urinary oxalate levels

Special Precautions:
- Surgery: Inform surgeon of vitamin C supplementation; supports wound healing but may affect some lab tests
- Pregnancy: Safe and may be beneficial; doses up to 2,000 mg considered safe
- Urine/blood tests: High doses can affect laboratory results for glucose and occult blood tests; inform healthcare provider
- Diabetics: Some urine test kits affected by high-dose vitamin C; use kits not affected

Primary Uses At-a-Glance

Primary: Immune support, cold and flu prevention/treatment, antioxidant protection, collagen synthesis for skin and wound healing, iron absorption enhancement

Secondary: Cardiovascular support, allergy/hay fever relief, adrenal support during stress, gum health, eye health (cataract prevention)

Sources

Local Library:
- Brewer, Sarah - TDT Encyclopedia of Vitamins
- Gaby, Alan R. - A-Z Guide to Drug-Herb-Vitamin Interactions 2nd Ed
- Moyad, Mark - The Supplement Handbook
- Virtue, Doreen - Nutrition for Intuition
- Mars, Brigitte - The Home Reference to Holistic Health and Healing
- Davis, Patricia - Aromatherapy an A-Z
- Bartram, Thomas - Bartrams Encyclopedia of Herbal Medicine
- Weil, Andrew - Eating Well for Optimum Health
- Worwood, Valerie Ann - The Complete Book of Essential Oils and Aromatherapy

General Knowledge:
- Cochrane Database of Systematic Reviews - Vitamin C for preventing and treating pneumonia
- Clinical trials database on vitamin C and common cold (30+ trials, 11,000+ participants)