Notes on Nutritional Disorders

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Dietary fuels:

Carbohydrates:

Glucose:

• Stored as glycogen.

• Used by RBCs.

• Oxidation produces 4 kcal/g.

• Digestion begins in mouth by salivary amylase.

• Salivary amylase and pancreatic amylase complement each other in CHO digestion.

• Brush border enzymes absorb disaccharides; hydrolysis of disaccharides produces glucose, galactose, fructose.

Proteins:

• Amino acids used in gluconeogenesis.

• Digestion begins in stomach.

• Oxidation produces 4 kcal/g.

• Pancreatic proteases and peptides used.

Fats:

Major form:

• Triglycerides.

• Used by all cells except RBCs and brain.

Essential fat:

• Linolenic acid is cardioprotective; linoleic acid is required for arachidonic acid synthesis.

• Digestion occurs primarily in SI.

Deficiency causes:

• Hair loss, dermatitis, poor wound healing.

• Pancreatic lipase used for hydrolysis; packed into chylomicrons and enter bloodstream.

• Oxidation produces 9 kacl/g.

Kwashiorkor:

• Inadequate protein intake.

• Too much carbohydrate intake.

• Pitting edema; ascites.

• Fatty liver.

• Diarrhea.

• Anemia; deficient immunity.

Marasmus:

• Inadequate intake of protein and other food.

• Muscle wasting.

• Growth retardation; anemia; deficient immunity.

Anorexia nervosa:

• Self-induced starvation.

• Distorted body-image.

• Amenorrhea; osteoporosis; lanugo; increased stress hormones (cortisol, GH, etc.).

Bulimia nervosa:

• Binging with self-induced vomiting.

Obesity:

• BMI over 30 kg/m2.

• Excess fat on waist is more harmful.

• Genetic predisposition: 50-80%.

• Defective leptin gene; syndrome X.

Obesity causes:

• Depression, cancer, diabetes mellitus 2, hypertension, obstructive sleep apnea, and more.

Fat-soluble vitamins:

Vitamin A:

• Produced from oxidation of retinol.

• Stored and transported as retinol.

• Derived from beta-carotene.

• Night vision.

• Immunity, growth and reproduction.

• Treatment of acne.

• Treatment of acute promyelocytic leukemia.

• Present in yellow/green vegetables.

Toxicity due to:

• Eating polar bear liver; overconsumption of exogenous vitamin A; treat with isotretinoin.

Toxicity findings:

• Papilledema, seizures, hepatitis, bone pain, etc.

Vitamin D:

• Present in fish and plants.

• Endogenous synthesis in sunlight.

• Reabsorption in SI.

• Kidney produces active form.

• Vitamin D increases calcium and phosphorous reabsorption in GI and urinary tracts.

• Required for mineralization of epiphyseal cartilage and osteoid matrix, and maintain calcium and phosphorous balance in serum.

Deficiency:

• Developmental abnormalities in bone, rickets, rachitic rosary, etc.

Deficiency caused by:

• Renal failure, inadequate sunlight, liver disease, fat malabsorption, P-450 induction.

Toxicity:

• Hypercalcemia, renal calculi.

Vitamin E:

• Antioxidant.

• Uncommon deficiency.

Deficiency:

• Anemia, peripheral neuropathy, spinocerebellar degeneration.

Toxicity:

• Decreased vitamin-K dependent procoagulant factors.

Vitamin K:

• Derived from endogenous bacteria and green vegetables.

• Activated in liver.

• Procoagulants and anticoagulants.

Deficiency caused by:

• Use of antibiotics, consumption of breast milk by newborns, liver dysfunction, fat malabsorption.

Deficiency findings:

• Newborns (hemorrhagic disease); adults (GI bleeding, prolonged PT and PTT).

Toxicity:

• Anemia, jaundice.

Water-soluble vitamins:

Thiamine (B1):

• Helps in ATP production.

Deficiency caused by:

• Alcoholism; consumption of non-enriched rice.

Deficiency:

• Dry and wet beribery, Wernicke's syndrome, Korsakoff's syndrome.

Riboflavin (B2):

• FAD and FMN are active forms.

• Deficiency caused by malnutrition.

Deficiency:

• Corneal neovascularization, glossitis, cheilosis, angular stomatitis.

Niacin (B3):

• NAD+; NADP+.

• Cofactors in redox reactions.

Deficiency:

• Pellagra (dermatitis, dementia, diarrhea).

Excess:

• Vasodilatation.

Pyridoxine (B6):

• Required for transamination, heme synthesis, neurotransmitter synthesis.

Deficiency caused by:

• Consumption of goat milk; isoniazid; alcoholism.

Deficiency:

• Anemia, convulsions, peripheral neuropathy.

Cobalamine (B12):

• Present in animal products.

• Used in DNA synthesis; odd-chain fatty acid metabolism.

Deficiency caused by:

• Strict vegan diet, anemia, ileal disease.

Deficiency:

• Anemia, neurologic disease, glossitis.

Folic acid:

• Present in most foods; used in DNA synthesis.

Deficiency due to:

• Insufficient dietary intake by elderly; consumption of goat milk, pregnancy, malabsorption.

Drugs:

• Alcohol, methotrexate, phenytoin, oral contraceptives, etc.

Deficiency findings:

• Anemia, glossitis, (NOTE: no neurologic disease).

Biotin:

• Cofactor in carboxylase reactions.

Deficiency caused by:

• Eating raw eggs; antibiotics.

Deficiency causes:

• Dermatitis, alopecia, lactic acidosis.

Ascorbic acid (vitamin C):

• Hydroxylation of lysine and proline residues in collagen synthesis.

• Antioxidant.

• Prevents nitrosylation.

• Iron absorption.

• FH4 is kept reduced.

Deficiency caused:

• lack of citrus fruits and vegetables; smoking.

Deficiency findings:

• scurvy, anemia, bleeding in skin.

Excess:

• renal calculi of uric acid.

Zinc:

• Used in wound healing.

Deficiency caused by:

• Alcoholism, diabetes mellitus, diarrhea, acrodermatitis enteropathica.

Causes:

• Poor wound healing, dermatitis, growth retardation.

Copper:

• Iron transport.

• Collagen and elastic tissue strength.

• Melanin synthesis.

Deficiency due to:

• Total parenteral nutrition (TPN).

Deficiency causes:

• Anemia, weak elastic tissue, poor wound healing.

Copper excess:

• Wilson's disease; lack of ceruloplasmin; Kayser-Fleischer rings.

Iodine:

• Synthesis of thyroid hormone.

• Inadequate intake of iodinated salt.

Causes:

• Goiter and hypothyroidism.

Chromium:

• Maintains normal glucose.

• Helps in insulin uptake.

Deficiency:

• Impaired glucose tolerance.

Selenium:

• Antioxidant.

Deficiency:

• Muscle pain, weakness.

Fluoride:

• Strengthened bones and teeth.

Deficiency causes:

• Dental caries.

Additional Reading:

Basic Pathology

1. Cell Injury
2. Inflammation and Repair
3. Immunopathology
4. Water, Electrolyte, Acid-Base, Hemodynamic Disorders
5. Genetic and Developmental Disorders
6. Environmental Pathology
7. Nutritional Disorders
8. Neoplasia
9. Vascular Disorders
10. Heart Disorders
11. Red Blood Cell Disorders
12. White Blood Cell Disorders
13. Lymphoid Tissue Disorders
14. Hemostasis Disorders
15. Blood Banking and Transfusion Disorders
16. Upper and Lower Respiratory Disorders
17. Gastrointestinal Disorders
18. Hepatobiliary and Pancreatic Disorders
19. Kidney Disorders
20. Lower Urinary Tract and Male Reproductive Disorders
21. Female Reproductive and Breast Disorders
22. Endocrine Disorders
23. Musculoskeletal Disorders
24. Skin Disorders
25. Nervous System Disorders
26. Notes on Tissue Regeneration
27. A Table of Bleeding Disorders
28. FAQ on Structure and Function of Red Blood Cells
29. FAQ on Components of Blood
30. Notes on Hemostatic Mechanisms
31. What is Fever?
32. What is Edema?
33. FAQ on Blood Pressure
34. FAQ on principles of fluid and flow dynamics of Blood
35. Causes of Thrombocytopenia
36. Squamous cell carcinoma of head and neck mucosa
37. Four tumors which never metastasize to the brain
38. What is caustic injury?
39. What causes Peripheral Edema?

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