Vitamins

vitamin A

  • Key Functions: Maintain epithelial health, support vision, play a role in reproduction.

  • Food Sources: Animal liver, dark leafy vegetables.

  • retinol →(reversible) retinal → (irreversible) retinoic acid, which is crucial for gene expression and cellular differentiation.

  • bioavailability

  • Deficiency Symptoms: Night blindness, xerophthalmia (dry cornea).

  • At-Risk Individuals: Pregnant women, children in developing countries.

  • Absorption Factors: Fat intake enhances absorption, while excessive alcohol intake can inhibit absorption.

Vitamin D

  • Key Functions: Calcium absorption, bone health, supports immune function.

  • Food Sources: Fatty fish, fortified dairy products.

  • Deficiency Symptoms: Rickets in children, osteomalacia/osteoporosis in adults.

  • At-Risk Individuals: Elderly, individuals with limited sun exposure, those with darker skin.

  • Absorption Factors: Absorption enhanced by having enough magnesium and fat in the diet.

Vitamin E

  • Key Functions: Acts as an antioxidant, prevents oxidative damage to cell membranes, supports immune function.

  • Food Sources: Vegetable oils, nuts.

  • Deficiency Symptoms: Neuromuscular issues, hemolysis in infants.

  • At-Risk Individuals: Individuals with fat malabsorption, premature infants.

  • Absorption Factors: Fat intake promotes absorption; higher intake of polyunsaturated fats may inhibit it.

Vitamin K

  • Key Functions: Blood clotting, bone mineralization, supports cardiovascular health.

  • Food Sources: Green leafy vegetables, fermented foods.

  • Deficiency Symptoms: Bleeding problems, potential for excessive blood loss.

  • At-Risk Individuals: Individuals on long-term antibiotic therapy, those with malabsorption disorders.

  • Absorption Factors: Dietary fats enhance absorption; certain medications (e.g., antibiotics) can inhibit absorption.

Water-Soluble Vitamins

Vitamin C

  • Key Functions: Antioxidant, important for collagen synthesis, immune function, enhances iron absorption.

  • Food Sources: Citrus fruits, strawberries, bell peppers, broccoli.

  • Deficiency Symptoms: Scurvy, fatigue, weakened immune response.

B-Complex Vitamins

  • Types: B1 (Thiamine), B2 (Riboflavin), B3 (Niacin), B5 (Pantothenic acid), B6 (Pyridoxine), B7 (Biotin), B9 (Folate), B12 (Cobalamin).

  • Key Functions:

    • Energy Metabolism: B-complex vitamins play vital roles in converting carbohydrates, fats, and proteins into energy.

    • Coenzyme Components: Many B vitamins are key components of coenzymes that assist enzymes in biochemical reactions.

  • B9 (Folate):

    • Importance: Essential for fetal development; critical for preventing neural tube defects in pregnant women.

    • Food Sources: Dark leafy greens, legumes, fortified grains.

  • B12 (Cobalamin):

    • Importance: Vital for DNA synthesis and red blood cell formation; deficiency is common among vegetarians as it is found exclusively in animal food sources.

    • Food Sources: Meat, fish, dairy products.

  • Other B Vitamins (B1, B2, B3, B5, B6, B7):

    • May be tested, but less emphasis compared to B9 and B12.