Basic Nutritional Requirements

On this page

Energy & Macronutrients - Fuel & Builders

  • Energy: Unit Kcal. 1 Kcal = heat to raise 1kg water by 1°C.
    • Fuel Values (Kcal/g): CHO 4, Protein 4, Fat 9. (Alcohol 7 Kcal/g).
  • BMR: Minimum energy at rest. SDA/TEF: Energy to metabolize food (Protein highest ~30%).
  • Macronutrients (% daily energy):
    • Carbohydrates (CHO): 50-60%. Primary fuel.
    • Proteins: 10-15% (0.8-1 g/kg/day). Body building.
      • 📌 Essential AAs: PVT TIM HALL.
    • Fats: 20-30%. Concentrated energy; EFA (Linoleic $\omega$-6, Linolenic $\omega$-3) deficiency → phrynoderma. Energy density of macronutrients per gram

⭐ Atwater General Factors for physiological fuel values: Carbohydrates 4 Kcal/g, Proteins 4 Kcal/g, Fats 9 Kcal/g.

Fat-Soluble Vitamins - ADEK Superstars

  • Absorbed with fats; stored (liver, adipose); risk of toxicity. 📌 Mnemonic: "Fat ADEK".
  • A (Retinol): Vision, epithelial integrity, immunity.
    • Deficiency: Night blindness, Bitot's spots, xerophthalmia.
    • Prophylaxis: 1L IU (6-11mo), 2L IU (1-6yr) q6mo.
  • D (Calciferol): $Ca^{2+}/PO_4^{3-}$ balance, bone health.
    • Deficiency: Rickets, osteomalacia.
    • Sources: Sunlight ($D_3$), diet ($D_2, D_3$).
  • E (Tocopherol): Antioxidant, cell membrane protection.
    • Deficiency: Rare; hemolytic anemia, neuropathy.
  • K (Phylloquinone/Menaquinone): Clotting factors (II, VII, IX, X, C, S).
    • Deficiency: Bleeding; Hemorrhagic Disease of Newborn (HDN).
    • HDN Prophylaxis: 1 mg IM at birth. Fat-Soluble Vitamins ADEK: Sources, Functions, Deficiency

⭐ Vitamin A deficiency is a leading cause of preventable childhood blindness globally.

Water-Soluble Vitamins - B-C Vitality

  • General: Not stored (except B12); excess excreted. Coenzymes.
  • B-Complex:
    • B1 (Thiamine): TPP (carb metabolism). Deficiency: Beriberi, Wernicke-Korsakoff.
    • B2 (Riboflavin): FAD/FMN (redox). Deficiency: Ariboflavinosis (cheilosis, glossitis).
    • B3 (Niacin): NAD/NADP (from tryptophan). Deficiency: Pellagra (3Ds: Dermatitis, Diarrhea, Dementia).
    • B6 (Pyridoxine): PLP (amino acid metabolism). Deficiency: Neuropathy, sideroblastic anemia. Isoniazid ↑need.
    • B9 (Folate): THF (DNA synthesis). Deficiency: Megaloblastic anemia, NTDs. RDA (Pregnancy): 600 mcg.
    • B12 (Cobalamin): DNA synthesis, myelin. Needs intrinsic factor. Deficiency: Megaloblastic anemia, neurological damage.
  • Vitamin C (Ascorbic Acid): Antioxidant, collagen synthesis, ↑non-heme Fe absorption. Deficiency: Scurvy.

Clinical Manifestations of Vitamin Deficiencies

⭐ High dose niacin (B3) is used for hyperlipidemia but can cause flushing (prostaglandin-mediated).

Essential Minerals - Micro Mighty

  • Iron (Fe): O₂ transport (Hb, Mb); enzyme cofactor. Deficiency: Microcytic anemia, koilonychia, pica. RDA: Men 8 mg, Women 18 mg (pre-menopause).
  • Iodine (I): Thyroid hormones ($T_3, T_4$). Deficiency: Goiter, cretinism, hypothyroidism. RDA: 150 µg.
  • Zinc (Zn): Cofactor for >300 enzymes; immunity, wound healing, taste/smell. Deficiency: Growth retardation, acrodermatitis enteropathica, ↓immunity, delayed wound healing.
  • Selenium (Se): Antioxidant (glutathione peroxidase); thyroid hormone metabolism. Deficiency: Keshan disease (cardiomyopathy), Kashin-Beck disease.
  • Copper (Cu): Iron absorption/transport; enzyme cofactor (e.g., lysyl oxidase, cytochrome c oxidase). Deficiency: Menkes kinky hair syndrome, anemia. Excess: Wilson's disease.
  • Fluoride (F⁻): Dental/bone health; prevents caries. Optimal water fluoridation: 0.7 ppm. Excess: Dental & skeletal fluorosis.
  • Chromium (Cr): Glucose tolerance factor; potentiates insulin action.
  • Manganese (Mn): Enzyme activator (e.g., mitochondrial superoxide dismutase).
  • Molybdenum (Mo): Cofactor for xanthine oxidase, sulfite oxidase. Minerals: RDAs, dietary sources, deficiency, excess

⭐ Zinc deficiency is classically associated with acrodermatitis enteropathica, characterized by periorificial and acral dermatitis, alopecia, and diarrhea.

High‑Yield Points - ⚡ Biggest Takeaways

  • A balanced diet is crucial, supplying macronutrients (carbohydrates, proteins, fats) and micronutrients (vitamins, minerals).
  • Average adult energy requirement (sedentary Indian male): ~2100-2300 kcal/day.
  • Protein RDA: 0.8-1 g/kg body weight/day; requirements ↑ during growth, pregnancy, and lactation.
  • Essential Fatty Acids (EFAs) like linoleic acid and alpha-linolenic acid must be diet-derived.
  • Recommended Dietary Allowances (RDAs) are average daily nutrient intake levels sufficient for most healthy individuals.
  • Basal Metabolic Rate (BMR) accounts for the largest portion (~60-70%) of total energy expenditure.
  • Specific Dynamic Action (SDA), or thermic effect of food, is highest for proteins (~30%).

Practice Questions: Basic Nutritional Requirements

Test your understanding with these related questions

A patient on a maize diet presented with diarrhea, dementia and dermatitis. Which vitamin deficiency is responsible for these features

1 of 5

Flashcards: Basic Nutritional Requirements

1/10

_____ promotes greater retention of ingested fluoride, leading to fluorosis

TAP TO REVEAL ANSWER

_____ promotes greater retention of ingested fluoride, leading to fluorosis

Jowar (sorghum) (Millet)

browseSpaceflip

Enjoying this lesson?

Get full access to all lessons, practice questions, and more.

Start Your Free Trial