Vitamin C

USAGE AND EFFECTIVENESS

Usage	Effectiveness
High Blood Pressure	Mild effectiveness (Reduce blood pressure) Several clinical studies showed reduction in both systolic (blood pressure when the blood pumps) by 4 mmHg and diastolic blood pressure (blood pressure when the heart relaxes) by 2 mmHg while another only showed reduction in systolic blood pressure by 5 mmHg); analysis of clinical study can be better designed e.g. exclude patients with normal blood pressure; more evidence is needed.
High Cholesterol	Mild effectiveness (Reduce cholesterol levels) Shown in one strong clinical study to lower bad cholesterol level by 8 mg/dL and triglycerides (component of fats) by 20 mg/dL; more evidence is needed.
Vitamin C Deficiency	Effective (Increase vitamin C levels) Shown in two clinical studies to prevent and cure vitamin C defiency and reverse scurvy (complication of vitamin C deficiency) within 2 days to 3 weeks, and improve impaired tyrosine (amino acid) metabolism in infants; more evidence is needed.
Airway Infections due to Intense Exercise	Mild effectiveness (Reduce risk of exercise-induced airway tract infections) Several clinical studies showed prevention in upper airway tract infections and decrease in incidences of cold development by 20%; more evidence is needed.
Alzheimer’s Disease	Mild effectiveness (Prevent Alzheimer’s disease) Several population studies showed that dietary vitamin C intake lowered the risk of Alzheimer’s disease development by 17%; more evidence is needed
Anaemia	Mild effectiveness (Improve anaemia in dialysis patients) Two clinical studies showed increased hemoglobin (iron-rich protein in red blood cells) levels by 0.9 grams/dL, concentration of transferrin (protein in the blood that binds to iron) by 8%, and reduced recombinant erythropoietin (hormone produced by the kidney) drug dose by 17 U/kg per week; more evidence is needed.
Bowel Preparation	Mild effectiveness (For use as part of a bowel preparation before colonoscopy) Several clinical studies showed reduction in nausea, vomiting, bloating, and increased patient compliance when vitamin C was used together with polyethylene glycol (PEG); more evidence is needed.
Cervical Cancer	Mild effectiveness (Prevent cervical cancer) Two clinical studies showed that higher intake of vitamin C lowers the incidence of cancer cell growth by 33-42% and an increase of 50mg per day further lowers the incidence of cervical cancer by 8%; more evidence is needed.
Common Cold	Mild effectiveness (Reduce the risk of developing a cold) Several clinical studies showed that there may be a general reduction of the duration of symptoms by 1-1.5 days; vitamin C may be more effective in decreasing the incidence of cold in individuals with physical stress, and in improving symptoms in children than in adults. The above showed its effectiveness when taken at the onset of cold; taking vitamin C to prevent common cold may not be effective. Consuming 2 grammes of vitamin C daily may be better than 1 gramm. More evidence is needed.
Irregular Heartbeats	Mild effectiveness (Prevent irregular heartbeats after heart surgeries) Generally, clinical studies showed that vitamin C may reduce the risk of irregular heartbeats after surgery by 27-53% and effectiveness whether vitamin C was used alone from one to three days before and four to five days after the heart surgery or in combination with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). However, analysis of studies conducted exclusively in USA showed ineffectiveness in reduing irregular heartbeats after surgery); more evidence is needed.
Lead Toxicity	Mild effectiveness (Reduce the concentration of lead) Several population studies showed that higher oral intake of vitamin C was associated with lower lead concentrations in the blood; more evidence is needed.
Nitrate Tolerance	Mild effectiveness (Prevent nitrate tolerance) Two clinical studies showed effectiveness in oral intake of vitamin C in the prevention of nitrate tolerance and short term intake of vitamin C supplements prevented dilation of blood vessels due to nitrate tolerance; more evidence is needed. Nitrate is a common medicine for heart patients to relieve chest pain. Nitrate Tolerance is a condition where continuous doses of medication containing nitrate leads to the development of nitrate resistance in the body, resulting in the ineffectiveness of nitrate medications in expanding the blood vessels to improve blood flow and chest pain.
Postoperative Pain	Mild effectiveness (Reduce chronic post-surgery pain) Several clinical studies showed reduction in pain severity after surgery and usage of painkillers from 5.7 grammes to 3.4 grammes; more evidence is needed.
Scar	Mild effectiveness (Reduce redness after laser skin resurfacing for scars and wrinkles removal) One clinical study showed reductions in the severity and duration of skin redness after the resurfacing procedure when vitamin C was applied; more evidence is needed.
Wrinkle	Mild effectiveness (Reduce the appearance of wrinkles) Several clinical studies showed that vitamin C preparations reduced the appearance of wrinkles, and combination of vitamin C with other ingredients improved skin tone, wrinkles appearance, sun damage, discolouration, and roughness; but clinical studies are not robust enough (unclear if benefits, other than wrinkles reduction, is due to vitamin C alone); more evidence is needed
Pain	Unclear effectiveness (Reduce risk of complex regional pain syndrome development) Several clinical studies showed conflicting results (Some showed reduced risk in patients with bone fractures, especially wrist fractures while others showed no prevention in complex regional pain syndrome); more evidence is needed.

General Safety

• Generally safe when used appropriately.

Pregnant/ Breastfeeding

• Generally safe when used orally and appropriately.

Children

• Generally safe when used orally and appropriately.

Elderly

• With regards to usage of Vitamin C as a supplement, there is little data to show it is safe or otherwise; avoid if possible; as food, avoidance of Vitamin C is not needed.

Special to Note

• Unknown.

Contraindications

• Details:
  • May theoretically worsen cancer in cancer patients.
  • May worsen form kidney stones and worsen preexisting chronic kidney disease or kidney stones.
  • May cause jaundice in patients with G6PD deficiency.
  • May cause precancerous mouth sores in those who chew tobacco.

Side Effects

• Generally safe; side effects may include:
  • Heart:May cause increased death risk, thickening of blood vessels in men, high blood pressure, and high blood pressure during pregnancy
  • Dental:May cause teeth erosion
  • Skin:May cause tingling sensation and skin irritation on the area where vitamin C is applied directly
  • Digestive System:May cause nausea, vomiting, inflammation at the esophagus, heartburn, stomach cramps, bowel obstruction, and diarrhoea; Rare cases of increased thirst, loose stools, and severe stomach upset
  • Genital/Urinary:May cause kidney stones, presence of crystals or kidney stones in urine, high oxalate levels in urine, high uric acid levels in urine, and blood in urine; Rare cases of blood in rine, high clearance rate of oxalate, and kidney stone
  • Blood:May cause high metabolism rate of vitamin C when a high dose is taken, and may cause vitamin C deficiency when dose is reduced
  • Brain/CNS:May cause tiredness, headache, insomnia, and drowsiness

• Medicines
  Low to High severity interactions with medicines for pain, cancer, blood thinning, inflammation, schizophrenia, HIV/AIDS, thyroid, containing aluminium, estrogens, and niacin (vitamin B3).
• Supplements
  Medium to High severity interactions with herbs and supplements containing acerola, chromium, copper, grape, iron, rose hip, and vitamin B12.
• Food
  Interacts with food such as grape and acerola.
• Lab Tests
  Interacts with lab tests for acetaminophen, liver damage, liver health, carbamazepine, creatinine, blood sugar level, tissue damage, blood in stools, theophylline (medication for airway diseases), and vitamin B12.

• Oral (Adults):
  90 mg (Men, 19 years and above); 75 mg (Women, 19 years and above); 120 mg (Pregnant/Breastfeeding, 19 to 50 years); 115 mg (Pregnant/Breastfeeding, 18 years and younger)|Oral (Children):Breast milk content (0-12 months); 15 mg (1-3 years); 25 mg (4-8 years); 45 mg (9-13 years); 75 mg (Boys, 14-18 years); 65 mg (Girls, 14-18 years)

• General Information
  • Vitamin C is used by consumers for Vitamin C deficiency, immunity, and others.
• How does it work?
  • Vitamin C is a water-soluble vitamin essential for several metabolic processes; one key effect is its antioxidant action; it may help with common cold, anaemia, high blood pressure, wrinkles, and others.