Vitamins part 2

Water-Soluble Vitamins

• Vitamins: B1, B2, B3, B6, B9 (Folic Acid), B12, C

  • Essential nutrients that are not stored in the body.

Vitamin C (Ascorbic Acid)

• Functions:

  • Antioxidant properties: neutralizes free radicals, with vitamin E

  • Maintains iron in ferrous form (Fe2+) → converts Fe3+ to Fe2+, facilitating better absorption in the intestines.

  • Cofactor for hydroxylases in collagen synthesis

  • Converts cholesterol into bile acids

  • Supports hormone synthesis in adrenal glands

  • Vital for immune system function

• RDA: 70-100 mg, can go up to 1000 mg in certain situations.

• Sources: Rose-hip, currants, apples, spinach, broccoli, tomato, citrus fruits.

• Causes of Deficiency:

  • Decreased intake due to cooking, elderly, lack of fresh produce

  • Increased need during pregnancy, lactation, and infections

• Symptoms of Deficiency:

  • Scurvy, vascular purpura, slow wound healing, gingival bleeding, loosened teeth, increased infection risk.

• Symptoms of Overdose: Rare but possible kidney stones (oxalate, urate stones).

Vitamin B1 (Thiamine)

• Functions:

  • Coenzyme for carbohydrate metabolism (TPP) and ATP production

  • Decarboxylation of α-ketoacids

  • Important for glucose-dependent tissues like smooth muscle and neural tissues

• RDA: 1-3 mg

• Sources: Vegetables, eggs, meat, the outer coat of grains

• Causes of Deficiency:

  • Low intake from husked rice or white bread

  • Malabsorption due to chronic diarrhea

  • Increased demands during rapid growth, pregnancy, lactation

• Symptoms of Deficiency:

  • Beri-beri (dry: neural symptoms, wet: cardiovascular failure)

• Symptoms of Overdose: None reported.

Vitamin B2 (Riboflavin)

• Functions:

  • Serves as a coenzyme for FMN and FAD (electron transport)

  • Involved in metabolism of other vitamins (B6, folic acid)

  • Important for glutathione reductase enzyme and monoamine oxidase (MAO)

• RDA: 2-6 mg/day

• Causes of Deficiency:

  • Complex B-hypovitaminosis, hypothyroidism

  • Antidepressant medications

• Symptoms of Deficiency:

  • Inflammation of GI mucosa and skin (stomatitis, glossitis, cheilosis)

  • Microcytic hypochromic anemia

• Symptoms of Overdose: Not known.

Vitamin B3 (Niacin)

• Functions:

  • Coenzyme for NAD and NADP involved in catabolic and anabolic processes

• RDA: 20-25 mg/day

• Causes of Deficiency:

  • Low intake of meat, high consumption of corn which binds niacin

  • Chronic diarrhea affects absorption

• Symptoms of Deficiency: Pellagra (dermatitis, diarrhea, dementia)

• Symptoms of Overdose: High doses can cause erythema and liver damage.

Vitamin B6 (Pyridoxine)

• Functions:

  • Amino acid metabolism and synthesis of neurotransmitters (GABA, dopamine)

  • Coenzyme for transsulfuration and immune function

• RDA: 2 mg/day

• Causes of Deficiency:

  • Low intake from heat-treated baby foods or alcohol dependence

• Symptoms of Deficiency:

  • CNS convulsions, microcytic hypochromic anemia, atherosclerosis

• Symptoms of Overdose: Can cause CNS disorders.

Vitamin B9 (Folic Acid)

• Functions:

  • Carries C1 groups for DNA synthesis and cell division

  • Vital for fetal nervous system development

• RDA: 0.5-2 mg/day, higher in pregnancy

• Causes of Deficiency:

  • Heat sensitivity, elderly, alcoholism, absorption issues

• Symptoms of Deficiency:

  • Pernicious anemia, ineffective erythropoiesis, neural tube defects.

Vitamin B12 (Cyanocobalamin)

• Functions:

  • Metabolism of homocysteine and fatty acids, maintaining proper myelin sheath

• RDA: 1-3 µg

• Causes of Deficiency: Low intake in vegetarians, absorption concerns (intrinsic factor issues, small intestine disorders).

• Symptoms of Deficiency: Pernicious anemia, neurological symptoms (paresthesia, ataxia), and irreversible damage possible.

Iron (Fe)

• Function:

  • Essential for hemoglobin, myoglobin, and certain enzyme functions

• Absorption: Enhanced in Fe2+ form with gastric acid.

• Requirement: 10-30 mg/day.

• Causes of Deficiency:

  • Low intake from strict vegetarian diet, absorption issues from lack of gastric acid, and increased need during certain life stages.

• Symptoms of Deficiency: Microcytic hypochromic anemia, angular stomatitis, chronic fatigue.