Vitamin C (Ascorbic acid)

Sample for Vitamin C

1. Serum or plasma can be used.
2. The whole blood for vitamin C is stable for 3 hours when refrigerated.
3. Deproteinized the serum or plasma with metaphosphoric acid (5 g/dL) or trichloroacetic acid (10 g/dL).

Precautions for Vitamin C

• Avoid hemolysis.

Pathophysiology of Vitamin C (Ascorbic acid)

1. Vitamin C can be synthesized by plants and some animals but not by humans. So dietary intake is important for humans.
2. This is a white crystalline solid that is easily soluble in water and easily absorbed from the stomach and intestine.
   1. These are strong reducing compounds, and the source is dietary ingestion.
   2. Body stores can last for months.
3. Vitamin C serves as a reducing agent in several hydroxylation reactions in the body.
4. This exists in two forms:
   1. L-ascorbic acid.
   2. Dehydroascorbic acid (Ascarbone).
      1. This form is more labile and biologically active.
5. Absorption is mainly from the stomach and small intestine.
   1. This has passive entry into the WBCs and RBCs.
   2. Active entry is into glandular tissue like the pituitary gland, adrenal cortex, corpus luteum, and thymus. At the same time, concentration in the retina is 20 to 30 times more than in tissue.
6. Vitamin C is excreted in the urine. Its excretion is increased by:
   1. Aspirin.
   2. Aminopyrine.
   3. Barbiturates.
   4. Paraldehyde.
   5. Hydantoin.

Vitamin C functions:

1. Vitamin C has a very important function in our body.
2. It is a water-soluble vitamin.
3. This is essential for the conversion of proline and lysine in procollagen to hydroxyproline and hydroxylysine.
   1. Vitamin C is essential in the formation and stabilization of the collagen.
4. Vitamin C may be involved in the stimulation of the synthesis of collagen.

Source of vitamin C:

1. The best source of Vitamin C is :
   1. Citrus fruits. This is the major source.
   2. Berries.
   3. Melons.
   4. Green pepper.
   5. Tomatoes.
   6. Raw cabbage.
   7. Leafy green vegetables.
   8. Potatoes.
2. Heat can lead to the loss of vitamin C.

Vitamin C absorption

Vitamin C deficiency:

Scurvy:

1. History of scurvy:
   1. In 1747, a naval surgeon found that citrus fruits help scurvy patients.
   2. This anti-scurvy agent was isolated in 1932 and was vitamin C.
   3. It was given the name of Ascorbic acid from its antiscorbutic effect.
2. Clinical effect of scurvy:
3. Several months are needed before the scurvy develops.
4. It leads to Scurvy which will show clinically:
5. Hemorrhagic disorder. There may be bruising and ecchymosis.
   1. Impaired college synthesis leads to petechiae and bruising.
6. There are swollen and bleeding gums.
7. There is a loss of teeth.
8. There is impaired healing.
9. There is anemia.
10. There is weakness in the lower extremities.
11. Summary of the scurvy:
    1. Early weakness, lassitude, and irritability.
    2. Vague aches and pain.
    3. In the late stage, hemorrhage into the skin, GI tract, and urinary tract.
       1. There are osteoporotic changes in the bone,.
       2. Defective tooth formation.
       3. There is anemia.
       4. There is delayed wound healing.
       5. There may be a fever.

Normal Vitamin C (Ascorbic acid)

Source 1

• Vitamin C = 0.4 to 1.5 mg/dL
• Deficiency level = <0.2 mg/dL

Other sources

1. Daily requirements of vitamin C:
   1.  Infants
      1. 0 to 6 months =  40 mg/day
      2. 7 to 12 months = 50 mg/day
   2. Children
      1. 1 to  3 years =  15 mg/day
      2. 4 to 8 years = 25 mg/day
      3. 9 to 13 years =  45 mg/day
   3. Adolescents
      1. Girls 14 to 18 years = 65 mg/day
      2. Pregnant teens =  80 mg/day
      3. Breastfeeding teens =  115 mg/day
      4. Boys 14 to 18 years = 75 mg/day
   4. Adults
      1. Men age 19 and older =  90 mg/day
      2. Women age 19 years and older: = 75 mg/day
      3. Pregnant women =  85 mg/day
      4. Breastfeeding women = 120 mg/day
2. Vitamin C normal range = 0.2 to 2.0 mg / 100 ml.
   1. Deficiency when a level is < 0.2 mg/dL.
3. Vitamin C level in Leucocytes = 20 to 53 µg/10⁸ leucocytes.
   1. Deficient value when it is  <10 µg / 10⁸ leucocytes.
4. Urinary excretion of vitamin C = 8 to 27 mg/day.

Deficiency of Vitamin C, Clinical effects of decreased vitamin C:

1. Prolonged deficiency leads to Scurvy.
2. There is an inadequate formation of intercellular substances in the connective tissue leads to the following:
   1. Swollen, tender, and sometimes bleeding into the joints.
   2. Gums are swollen.
3. Infantile scurvy, also knew Barlow’s disease, will show bayonet rib syndrome.
4. There is vascular fragility leads to:
   1. Cutaneous bleeding and usually starts in the lower thigh and may spread to the buttocks, abdomen, arms, and legs.
   2. Petechial hemorrhage may lead to a large bruise.
   3. There is an ocular hemorrhage.
   4. Bleeding in the GI tract, kidneys, conjunctiva, and brain.
   5. Hemorrhage of the gingiva.
5. There may be dental loss and even fractures.
6. There is delayed wound healing.
7. Other glands like salivary, lacrimal, and parotid may be involved.
8. There may be femoral neuropathy and edema of the lower extremities.

Toxicity of Vitamin C:

1. Large doses of vitamin C for allergies and colds are not recommended.
2. Large doses do not cause any problems except GI upset.
3. Increased oxalate stones in the kidney and urinary bladder due to acidification of urine.

Clinical effects of increased Vitamin C:

1. Diarrhea.
2. Nausea and dyspepsia.
3. Over absorption of iron.
4. A stone formation is like oxalate stones due to the increased secretion of oxalate.
5. There may be increased secretion of urates.
6. Effect on diabetes tests and occult blood.

Methods to measure Vitamin C:

1. This can be measured by:
   1. Photometric system
   2. Fluorometric and HPLC techniques can be used.

Treatment for Vitamin C deficiency:

•  The daily dose of  10 mg of vitamin C is sufficient to treat the clinical signs of scurvy.

Questions and answers: