Human Body & Medicine Module

Vitamins, Minerals & Human Nutrition

Human nutrition requires macronutrients (carbohydrates, proteins, lipids) and micronutrients (vitamins and minerals) to support metabolic functions and tissue repair. Vitamins are categorized into fat-soluble vitamins (A, D, E, K) and water-soluble vitamins (B-complex group and Vitamin C). Dietary deficiencies cause specific disorders: Vitamin A deficiency leads to xerophthalmia and night blindness; Vitamin B1 (thiamine) deficiency causes beriberi; Vitamin C (ascorbic acid) deficiency results in scurvy; and Vitamin D deficiency causes rickets in children and osteomalacia in adults. Essential dietary minerals include iron (required for hemoglobin synthesis; deficiency causes anemia), iodine (essential for thyroid hormone synthesis), and calcium for bone mineralization.

Practice Topic MCQs All Category Topics

Key Concepts & Examination Highlights

Fat-soluble vitamins (A, D, E, K) are stored in hepatic and adipose tissues, whereas water-soluble vitamins (B-complex and C) require regular dietary intake.
Vitamin B12 (cobalamin) is the only vitamin containing a metallic cobalt ion, and its deficiency causes pernicious anemia.
Iodine is essential for the synthesis of thyroxine ( $T_4$ ) and triiodothyronine ( $T_3$ ); severe iodine deficiency leads to endemic goiter.
Vitamin A (retinol) is essential for rhodopsin synthesis in retinal rod cells; severe deficiency causes night blindness (nyctalopia) and xerophthalmia.
Vitamin B1 (thiamine) deficiency impairs carbohydrate metabolism and leads to beriberi, which affects the cardiovascular and peripheral nervous systems.
Vitamin B3 (niacin) deficiency results in pellagra, a condition clinically characterized by the three Ds: dermatitis, diarrhea, and dementia.
Vitamin C (ascorbic acid) acts as an antioxidant and is crucial for collagen synthesis; its deficiency leads to scurvy, characterized by bleeding gums and delayed wound healing.
Vitamin D (cholecalciferol) facilitates intestinal calcium absorption; deficiency causes rickets in growing children and osteomalacia in adults.
Vitamin K (phylloquinone/menaquinone) is required by the liver for the post-translational synthesis of clotting factors II (prothrombin), VII, IX, and X.
Vitamin E (tocopherol) functions as a lipid-soluble antioxidant that protects cell membranes from reactive oxygen species and oxidative damage.
Iron is a core structural component of hemoglobin and myoglobin, and its dietary deficiency is the primary cause of nutritional microcytic hypochromic anemia.
Vitamin B2 (riboflavin) is a constituent of flavin coenzymes (FMN and FAD) involved in cellular energy metabolism, and its deficiency causes cheilosis, angular stomatitis, and glossitis.
Vitamin B6 (pyridoxine) acts as a coenzyme in amino acid transamination and neurotransmitter synthesis, and its deficiency leads to peripheral neuropathy and microcytic hypochromic anemia.
Vitamin B9 (folic acid / folate) is critical for nucleic acid synthesis and red blood cell maturation, and maternal folate deficiency during early pregnancy causes neural tube defects like spina bifida.
Vitamin B5 (pantothenic acid) is a fundamental component of Coenzyme A (CoA), which is necessary for the Krebs cycle and fatty acid synthesis.
Vitamin B7 (biotin) serves as a coenzyme for carboxylase enzymes in gluconeogenesis and fatty acid metabolism, and its absorption is inhibited by raw egg white avidin.
Vitamin E (tocopherol) functions as a lipid-soluble antioxidant protecting cellular membrane phospholipids from free radical lipid peroxidation, and its deficiency causes hemolytic anemia and ataxia.
Calcium is the most abundant mineral in the human body, vital for bone mineralization, neuromuscular transmission, muscle contraction, and blood coagulation.
Potassium is the principal intracellular cation ( $K^+$ ), maintaining resting membrane potential and cellular osmotic balance, while sodium ( $Na^+$ ) is the major extracellular cation regulating extracellular fluid volume.
Zinc is an essential trace mineral required for over 300 metalloenzymes, wound healing, immune response, and the sense of taste (gustation).
Dietary fibers (roughage), consisting of indigestible complex carbohydrates like cellulose and lignin, add bulk to stool, stimulate peristalsis, and lower serum LDL cholesterol.
Essential fatty acids, including linoleic acid (omega-6) and alpha-linolenic acid (omega-3), cannot be synthesized de novo by humans and must be acquired through diet.
Kwashiorkor is a form of severe acute malnutrition caused primarily by severe protein deficiency despite adequate caloric intake, characterized by peripheral edema, hepatomegaly, and abdominal distension.
Marasmus is a form of severe malnutrition caused by total caloric and protein deficiency, characterized by severe muscle wasting, loss of subcutaneous adipose tissue, and an emaciated appearance without edema.
Fluoride in optimal concentrations (0.7-1.2 mg/L) prevents dental caries by forming fluorapatite in enamel, but excessive intake above 1.5 mg/L causes dental and skeletal fluorosis.
Vitamin K occurs in two natural forms: Vitamin K1 (phylloquinone), synthesized by green leafy plants, and Vitamin K2 (menaquinone), synthesized by gut microbiota.
Vitamin D3 (cholecalciferol) undergoes two successive hydroxylations: first in the liver to form 25-hydroxyvitamin D [25(OH)D], and second in the kidneys to form active calcitriol [1,25(OH)2D].
Vitamin C enhances the intestinal absorption of non-heme dietary iron by reducing ferric ( $Fe^{3+}$ ) iron to the more soluble ferrous ( $Fe^{2+}$ ) state.
Folic acid (Vitamin B9) serves as a single-carbon donor in purine and thymidylate synthesis, essential for cellular division and fetal neural tube closure.
Coenzyme Q10 (ubiquinone) is a lipid-soluble benzoquinone compound that functions as an electron carrier in the mitochondrial electron transport chain between Complexes I/II and Complex III.
Magnesium is an essential intracellular divalent cation required as a cofactor for over 300 enzymatic reactions, including all reactions involving ATP utilization and transfer.
Phosphorus is the second most abundant mineral in the body, primarily combined with calcium in bones and teeth as hydroxyapatite crystals and forming the backbone of DNA and RNA.
Selenium is an essential trace element incorporated into selenoproteins such as glutathione peroxidase, which protects cellular membranes from oxidative degradation.
Copper is a required cofactor for key metalloenzymes including cytochrome c oxidase (electron transport) and lysyl oxidase (collagen cross-linking); severe excess accumulation causes Wilson's disease.
Manganese functions as a cofactor for arginase, pyruvate carboxylase, and mitochondrial superoxide dismutase (Mn-SOD), participating in amino acid, cholesterol, and carbohydrate metabolism.
Molybdenum is a trace element cofactor for enzymes including xanthine oxidase, aldehyde oxidase, and sulfite oxidase involved in purine and sulfur amino acid catabolism.
Chromium ( $Cr^{3+}$ ) enhances the biological action of insulin by facilitating insulin receptor binding, playing a role in carbohydrate and lipid metabolism.
Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are long-chain omega-3 polyunsaturated fatty acids vital for neurocognitive development, retinal function, and cardiovascular health.
Choline is an essential water-soluble nutrient required for synthesizing phosphatidylcholine (cell membrane structure), sphingomyelin, and the neurotransmitter acetylcholine.
L-carnitine transports long-chain fatty acids across the inner mitochondrial membrane via the carnitine shuttle for beta-oxidation and energy production.
Creatine, synthesized in the liver and kidneys from arginine, glycine, and methionine, is phosphorylated into phosphocreatine to rapidly regenerate ATP during high-intensity muscle contraction.
Tryptophan is an essential amino acid that serves as the biochemical precursor for the synthesis of the neurotransmitter serotonin, the sleep hormone melatonin, and vitamin B3 (niacin).
Phenylalanine is an essential aromatic amino acid converted by phenylalanine hydroxylase into tyrosine; genetic deficiency of this enzyme results in phenylketonuria (PKU).
Glycemic Index (GI) ranks carbohydrate foods on a scale from 0 to 100 based on how rapidly and significantly they raise postprandial blood glucose levels compared to pure glucose.
Basal Metabolic Rate (BMR) is the baseline rate of energy expenditure per unit time by endothermic animals at rest in a post-absorptive state in a neutrally temperate environment.
Dietary potassium blunts the blood-pressure-raising effects of sodium by promoting urinary sodium excretion (natriuresis) and inducing vascular smooth muscle relaxation.
Dietary antioxidants (such as polyphenols, flavonoids, carotenoids, and tocopherols) scavenge free radicals and reactive oxygen species (ROS), mitigating cellular oxidative stress.
Probiotics are live beneficial microorganisms (such as Lactobacillus and Bifidobacterium) that confer digestive and immunological health benefits on the host when administered in adequate amounts.
Prebiotics are non-digestible soluble dietary fibers (such as inulin and fructooligosaccharides) that selectively stimulate the growth and metabolic activity of beneficial gut microbiota.
Lactose intolerance is caused by deficiency of the brush-border enzyme lactase in the small intestine, leading to bacterial fermentation of unabsorbed lactose into lactic acid, methane, and hydrogen gas.

Curriculum & Reference Sources: World Health Organization (WHO Nutrition Guidelines), ICMR-National Institute of Nutrition (NIN), NIH Office of Dietary Supplements

Sample Solved Questions & Concept Explanations

8 Verified Concept Questions

Q1.EASY

Deficiency of which water-soluble vitamin causes "Scurvy", characterized by bleeding gums, skin hemorrhages, and poor wound healing?

Q2.EASY

Deficiency of which fat-soluble vitamin causes "Night Blindness" (Nyctalopia) and Xerophthalmia in children?

Q3.EASY

Deficiency of which vitamin causes "Rickets" (soft, weakened, and bowed bones) in growing children and Osteomalacia in adults?

Q4.EASY

Deficiency of which essential dietary mineral causes "Goitre" (abnormal enlargement of the thyroid gland in the neck)?

Q5.EASY

Deficiency of which essential mineral in the human diet causes nutritional "Anemia", characterized by chronic fatigue and low hemoglobin counts?

Q6.EASY

Deficiency of Vitamin B1 (Thiamine) in individuals consuming polished white rice diets causes which neurological and cardiovascular disorder?

Q7.EASY

Deficiency of Vitamin B3 (Niacin / Nicotinic acid) causes "Pellagra", clinically characterized by which classic "3 Ds" triad of symptoms?

Q8.EASY

Deficiency of Vitamin B12 (Cobalamin) in strict vegans or individuals with low stomach intrinsic factor causes which type of anemia?