Vitamin E (α-Tocopherol)

 Vitamin E (α-Tocopherol)

Sample

1. The patient plasma is needed. For plasma take a sample in heparin.
2. A fasting sample is preferred.
3. The sample is stable at 4 °C for 4 weeks and at -20 or -70 °C for one year.
4. Protect from light.

Precaution

1. Avoid the use of alcohol at least 24 hours before taking the blood sample.
2. Protect the sample from light.

Pathophysiology

1. This is a powerful antioxidant vitamin.
   1. Oxidants which cause the disease, aging, and cleavage of fatty acids.
2. This vitamin is soluble in fat solvents and insoluble in water.
   1. Its generic name is tocopherol which includes several biologically active isomers.
      1. α-tocopherol is the predominant isomer and is the biologically active form.
   2. It is viscous oil at room temperature.
   3. Stable to heat in the absence of oxygen.
3. It plays a role in cellular respiration.
4. The vit E contains 8 related natural compounds that are biosynthesized in plants and these are abundant in the vegetables.
   1. Eight Vitamin E subtypes are tocopherols and tocotrienols.
   2. Its most active unit is α-tocopherol.
5. Its main function is antioxidants.
6. Its absorption takes place in the presence of bile in the small intestine.
   1. Most of the tocopherol enters the bloodstream via lymph. So it is associated with chylomicron and very-low-density lipoprotein.
7. Sources of vitamin E are:
   1. Vegetable oils.
   2. Fresh leafy vegetables.
   3. Eggs and yolk.
   4. Legumes.
   5. Peanuts.
   6. Margarine.

Vitamin E Absorption

1. 2. Most of it is stored in the adipose tissue.
   3. When the normal dose of Vit, E is given then a very small amount appears in the urine.

Vitamin E and Absorption

8. Functions:
   1. Antioxidant of the unsaturated fatty acids.
   2. Protect from the free radicals.
   3. Prevent the oxidation of vitamin A, DNA, and phospholipids of the cell membrane.
   4. Acts with selenium for the maintenance of cell membranes. This effect may be more neuronal. Due to Vit, E deficiency there is irritability and edema.
      1. There is peripheral neuropathy.
      2. There is a degeneration of the spinal cord.
      3. Vitamin E protects the RBC’s cell membrane from oxidants.
         1. The anemia is due to the fragile RBC membrane and there is no response to iron therapy.
         2. Hemolytic anemia in infants.
      4. These symptoms due to its deficiency are rare except in the case of malabsorption.
9. Clinical presentation of vitamin E deficiency:
   1. The major symptom is hemolytic anemia.
   2. A relationship exists between vitamin E  deficiency and progressive loss of neurological function in infants and children with chronic cholestasis.

Normal

Source 1

1.  Some recommend > 0.5 mg / 100 ml.
2. Premature neonates  = 0.31 to ± 0.06 mg/dL.
3. 1 to 12 years = 0.3 to 0.9 mg/dL
4. 13 to 19 years = 0.6 to 1.0 mg/dL
5. Adult  = 0.5 to 1.8 mg/dL
6. Deficiency =  <0.3 mg/dL
7. Excess level  =  >4 mg/dL

Another source

• Recommended daily for adults male = 10 mg/day.
  • For female = 8 mg/day.