Vitamins

Course Title and Authors

  • Nutrition Science and Applications

  • Smolin and Grosvenor

  • Professor Xiao Ningxin

Table of Contents

  • Section 1: Introduction to Vitamins

  • Section 2: Fat-Soluble Vitamins

  • Section 3: Water-Soluble Vitamins

Section 1: Introduction to Vitamins

Definition of Vitamins

  • Essential organic nutrients that do not provide energy but are necessary for...

    • Growth, reproduction, and health maintenance.

Classification of Vitamins

  • Water-Soluble Vitamins: B-complex, C

  • Fat-Soluble Vitamins: A, D, E, K

General Functions

  • Promote growth and overall health

  • Maintain normal reproductive functions

  • Ensure proper digestion and absorption

  • Encourage vital mental health and disease resistance

Sources of Vitamins

  • Essential nutrients must be acquired through diet.

Section 2: Fat-Soluble Vitamins

General Characteristics

  • Stored in liver and adipose tissue

  • Absorption affected by dietary fat

Vitamin A

  • Chemical Properties: Active form is retinol; precursor from beta-carotene.

  • Physiological Functions:

    • Normal vision

    • Epithelial function

  • Food Sources: Carrots, fish liver oil, leafy greens.

  • Deficiency Symptoms: Night blindness, dry eyes.

  • Toxicity Symptoms: Stomachache, vomiting, headaches.

Vitamin D

  • Chemical Properties: D2 from ergosterol and D3 from 7-dehydrocholesterol.

  • Physiological Functions:

    • Regulates calcium and phosphorus in blood.

    • Supports bone and teeth development.

  • Food Sources: Liver, salmon, milk.

Vitamin E

  • Chemical Properties: Tocopherol, active form is alpha-tocopherol.

  • Physiological Functions: Antioxidant, prevents infertility and blood clotting; stored in liver.

  • Food Sources: Vegetable oils, grains, nuts.

Vitamin K

  • Chemical Properties: K1 from plants, K2 from intestinal bacteria.

  • Physiological Functions: Necessary for blood clotting.

  • Food Sources: Dark green vegetables, dairy.

Section 3: Water-Soluble Vitamins

General Characteristics

  • Cannot be stored in the body; excreted via urine.

Vitamin B1 (Thiamine)

  • Absorption: In duodenum; degraded by tea and raw seafood.

  • Physiological Functions: Coenzyme in energy metabolism.

  • Deficiency: Beriberi symptoms.

Vitamin B2 (Riboflavin)

  • Chemical Properties: Exists in free form or as coenzymes (FMN, FAD).

  • Physiological Functions: Important for energy production and cellular function.

  • Deficiency Symptoms: Angular stomatitis, dermatitis.

Vitamin B3 (Niacin)

  • Chemical Properties: Exists as nicotinic acid and nicotinamide.

  • Physiological Functions: Coenzymes in energy metabolism (NAD, NADP).

  • Deficiency Disease: Pellagra (dermatitis, diarrhea, dementia).

Vitamin B6 (Pyridoxine)

  • Physiological Functions: Coenzyme in amino acid metabolism and synthesis of neurotransmitters.

  • Deficiency Symptoms: Lesions, irritability, and neuropathy.

Vitamin B7 (Biotin)

  • Physiological Functions: Important for fatty acid synthesis and energy metabolism.

  • Deficiency Symptoms: Dermatitis, alopecia.

Vitamin B9 (Folic Acid)

  • Physiological Functions: Necessary for RBC production and fetal development.

  • Deficiency Disease: Macrocytic anemia, neural tube defects.

Vitamin B12 (Cobalamin)

  • Physiological Functions: Involved in DNA synthesis and maintenance of myelin.

  • Deficiency Disease: Pernicious anemia.

Vitamin C (Ascorbic Acid)

  • Physiological Functions: Antioxidant, collagen synthesis, metabolism of amino acids.

  • Deficiency Disease: Scurvy.

Conclusion

  • Vitamins are crucial for optimum health, and deficiencies can lead to significant health risks. Awareness of sources and functions of each vitamin can guide individuals in maintaining a balanced diet.