Vitamins: Vitamin E Functions

Vitamin E

• Acts as a natural antioxidant due to the presence of the tocol ring, breaking free radicals.
• Maintains the integrity of the endothelium of blood vessels and stability of erythrocytes.
• Essential for normal spermatogenesis and continuation of pregnancy in rats.
• Increases the synthesis of Heme.
• Prevents the oxidation of vitamin A and β carotene.
• Protects against heart diseases by preventing the oxidation of LDL.

Vitamin E Deficiency

• Can lead to atherosclerosis and heart diseases.
• Causes oxidative stress, resulting in muscle weakness, arrhythmia, and vision problems.

Vitamin K

• Biochemical role depends on the synthesis of γ-carboxyglutamate.
• Essential for the hepatic synthesis of prothrombin and blood clotting factors VII, IX, and X.
• Interacts with platelets to form a prothrombin-calcium complex, which binds to phospholipids for blood clotting.
• Activates osteocalcin, converting pro-osteocalcin to osteocalcin.

Vitamin K Deficiency

• Uncommon due to adequate production by intestinal bacteria or obtained from the diet.
• Leads to internal and external hemorrhages.
• Caused by malabsorption syndrome, liver diseases, sterile intestine in newborns, prolonged use of antibiotics, and warfarin or dicumarol.

Folic Acid (Folate)

• Acts as a one-carbon metabolism, receiving one-carbon fragments and transferring them to amino acids, purines, and thymidine monophosphate (TMP) in DNA synthesis.
• Essential for DNA synthesis, synthesizing thymidine monophosphate (TMP).
• Necessary for the synthesis of red blood cells.
• Converts homocysteine to methionine, treating heart diseases.
• Prevents neural tube defects, such as Spina bifida and anencephaly.

Folic Acid Antagonists

• Methotrexate competitively inhibits folic acid reductase enzyme, blocking synthesis of nucleic acids and inhibiting cell division.
• Sulfonamides competitively inhibit folic acid reductase enzyme, preventing the formation of active forms of folic acid.

Folic Acid Deficiency

• Caused by increased demand, poor absorption, chronic alcoholism, diet lacking folic acid, drugs, and rapid growing cancer.
• Symptoms include megaloblastic anemia, leucopenia, thrombocytopenia, impaired growth, and neural tube defects.
• FIGLU test is a biochemical indicator of folate deficiency, accumulating in urine.