Vitamins & Minerals — Set 3

Correct Answer: B. Vitamin C

• **Vitamin C** = Vitamin C (ascorbic acid) is the most heat-labile and cooking-sensitive vitamin because it is simultaneously water-soluble (leaches into cooking water), highly sensitive to heat (degrades above 70°C), and oxidised rapidly in the presence of air and alkaline conditions. • **Triple vulnerability** — boiling vegetables destroys up to 80% of their Vitamin C through leaching, heat degradation, and oxidation simultaneously; steaming or microwaving for short durations preserves significantly more. • Storing cut or peeled vegetables for long periods also reduces Vitamin C content through oxidation, which is why fresh and raw consumption is best. • 💡 Option A (Vitamin K) is wrong because it is heat-stable and fat-soluble, retaining potency well during normal cooking; Option C (Vitamin D) is wrong because it is relatively heat-stable and its dietary sources (fatty fish, eggs) are not significantly degraded by cooking; Option D (Vitamin A) is wrong because while it can be oxidised, it is far more stable during cooking than Vitamin C.

Correct Answer: C. Vitamin A

• **Vitamin A** = Vitamin A is fat-soluble and accumulates in the liver; excessive intake — whether from very high doses of supplements or eating polar bear/seal liver — causes hypervitaminosis A, with symptoms including liver damage, increased intracranial pressure (headache, nausea), bone pain, hair loss, and teratogenicity (birth defects) if taken during pregnancy. • **Therapeutic danger** — high-dose Vitamin A supplements prescribed for measles prevention or skin conditions (like isotretinoin for acne) carry clear toxicity risks; even chronic intake of 3–4 times the recommended daily allowance can gradually damage the liver. • The condition 'Arctic explorer's disease' refers to acute Vitamin A toxicity in explorers who ate the livers of sled dogs or polar bears, which contain extremely high Vitamin A concentrations. • 💡 Option A (Vitamin B1/Thiamine) is wrong because it is water-soluble and excess is excreted in urine, making toxicity virtually impossible at dietary levels; Option B (Vitamin B2/Riboflavin) is wrong because it is also water-soluble with no known toxicity from food; Option D (Vitamin C) is wrong because though very high supplemental doses can cause kidney stones, it does not accumulate in the liver.

Correct Answer: B. Potassium

• **Potassium** = Potassium (K⁺) is the dominant intracellular cation and is central to the action potential in nerve and muscle cells; the sodium-potassium ATPase pump maintains a high intracellular K⁺ concentration, which establishes the resting membrane potential (-70 mV) essential for nerve impulse transmission. • **Resting potential mechanism** — when a neuron fires, sodium rushes in (depolarisation) and potassium rushes out (repolarisation), restoring the resting potential; potassium channels are thus critical at every stage of nerve signal propagation. • Low potassium (hypokalemia) causes muscle weakness, cramps, and dangerous cardiac arrhythmias because both muscle and nerve cells depend on the K⁺ gradient for electrical excitability. • 💡 Option A (Iron) is wrong because iron's primary role is in oxygen transport via haemoglobin and is not involved in nerve impulse conduction; Option C (Sulfur) is wrong because sulfur is found in amino acids (cysteine, methionine) and connective tissue proteins but is not an electrolyte involved in nerve signalling; Option D (Iodine) is wrong because iodine's function is restricted to thyroid hormone synthesis.

Correct Answer: B. Vitamin K

• **Vitamin K** = The gut microbiota in the large intestine produces Vitamin K2 (menaquinone); this bacterial synthesis contributes to the body's Vitamin K supply alongside dietary Vitamin K1 from green leafy vegetables, making Vitamin K unique among fat-soluble vitamins in having a gut-bacteria source. • **Antibiotic implications** — prolonged antibiotic treatment destroys gut bacteria and can significantly reduce Vitamin K2 synthesis, increasing the risk of bleeding; this is why surgical patients on antibiotics may require Vitamin K supplementation. • The liver uses Vitamin K to activate four coagulation factors (II, VII, IX, X); it also activates proteins C and S that inhibit clotting, giving Vitamin K a balancing role in haemostasis. • 💡 Option A (Vitamin C) is wrong because gut bacteria do not synthesise Vitamin C; humans must obtain it entirely from dietary sources; Option C (Vitamin A) is wrong because bacteria produce no Vitamin A; it comes from animal products and carotenoids in plants; Option D (Vitamin B1/Thiamine) is wrong because while some B vitamins are produced in small amounts by gut bacteria, B1 is not a significant product of large intestine bacteria in humans.

Correct Answer: D. Riboflavin

• **Riboflavin** = The chemical name 'riboflavin' combines 'ribose' (the sugar alcohol ribitol in its structure) and 'flavin' (from the Latin 'flavus' meaning yellow), reflecting the distinctive yellow-orange colour of this vitamin; riboflavin is the core component of the coenzymes FAD (flavin adenine dinucleotide) and FMN (flavin mononucleotide) that drive cellular energy production. • **Colour indicator** — riboflavin imparts a fluorescent yellow-green colour to urine when consumed in high doses, which is harmless; this visual cue is sometimes used to assess whether a vitamin B2 supplement has been absorbed. • Rich sources include organ meats, milk, eggs, mushrooms, and leafy vegetables; riboflavin deficiency (ariboflavinosis) causes cracked corners of the mouth (angular cheilitis), inflamed tongue, and eye sensitivity to light. • 💡 Option A (Niacin) is wrong because Niacin is the chemical name/common name for Vitamin B3; Option B (Thiamine) is wrong because Thiamine is the chemical name for Vitamin B1; Option C (Biotin) is wrong because Biotin is the chemical name for Vitamin B7.

Correct Answer: C. Chromium

• **Chromium** = Chromium is an essential trace mineral that potentiates the action of insulin; it is a component of Chromodulin (formerly called Glucose Tolerance Factor), a molecule that binds to and activates the insulin receptor, enhancing glucose uptake by cells and improving insulin sensitivity. • **Diabetes connection** — chromium deficiency impairs glucose tolerance and insulin sensitivity, resembling early Type 2 diabetes; chromium picolinate supplements have been studied for their potential to improve blood sugar control in diabetic patients. • The typical daily requirement for chromium is tiny — just 25–35 micrograms — yet modern diets high in refined foods are often low in chromium because processing removes it. • 💡 Option A (Iodine) is wrong because iodine is used exclusively for thyroid hormone synthesis and has no interaction with insulin; Option B (Iron) is wrong because iron functions in haemoglobin and cellular metabolism, not in insulin signalling; Option D (Fluorine) is wrong because fluoride's biological role is limited to strengthening tooth enamel and has no connection to insulin or glucose metabolism.

Correct Answer: D. Vitamin E

• **Vitamin E** = Vitamin E earns the title 'Beauty Vitamin' because as a powerful fat-soluble antioxidant, it protects skin cell membranes from oxidative damage caused by UV radiation and pollution, slowing signs of skin ageing; it also supports healthy hair follicles by protecting lipid-rich scalp membranes from free radical damage. • **Skin barrier role** — Vitamin E is abundant in sebum (the skin's natural oil) and works synergistically with Vitamin C; together they neutralise free radicals in both the aqueous and lipid layers of skin, making them the cornerstone duo of anti-ageing skincare formulations. • Vitamin E is a common active ingredient in moisturisers, sunscreens, and hair oils; its cosmetic popularity stems from its demonstrated ability to reduce UV-induced skin damage and improve skin hydration. • 💡 Option A (Vitamin A) is wrong because while retinol is used in anti-ageing creams and is crucial for skin cell turnover, it is more commonly called the 'Anti-Ageing Vitamin' or 'Vision Vitamin'; Option B (Vitamin C) is wrong because Vitamin C is popularly called the 'Immunity Vitamin' or 'Brightening Vitamin' for its role in collagen and skin tone; Option C (Vitamin B) is wrong because B-complex vitamins are associated with energy metabolism and neurological health, not skin beauty.

Correct Answer: B. Mild Anemia

• **Mild Anemia** = Vitamin B6 (Pyridoxine) is a cofactor for ALA synthase, the first enzyme in haem biosynthesis; its deficiency reduces haem production, leading to microcytic hypochromic anemia (small, pale red blood cells with low haemoglobin) — clinically milder than iron-deficiency anemia but sharing similar features. • **Broader B6 deficiency effects** — beyond anemia, severe Vitamin B6 deficiency causes peripheral neuropathy, dermatitis (seborrhoeic-like), glossitis, and in infants, seizures, since B6 is essential for GABA synthesis in the brain. • Pyridoxine deficiency can be induced by the tuberculosis drug isoniazid (INH), which inactivates B6; TB patients are therefore routinely co-prescribed Vitamin B6 supplements. • 💡 Option A (Beriberi) is wrong because Beriberi is caused by Vitamin B1 (Thiamine) deficiency; Option C (Scurvy) is wrong because Scurvy is caused by Vitamin C deficiency, causing bleeding gums and collagen breakdown; Option D (Rickets) is wrong because Rickets is caused by Vitamin D deficiency in children, causing soft and deformed bones.

Correct Answer: D. Fluorine

• **Fluorine (Fluoride)** = Fluoride ions replace hydroxyl groups in tooth enamel's hydroxyapatite to form fluorapatite [Ca₁₀(PO₄)₆F₂], which is significantly harder and more resistant to acid attack from oral bacteria than regular enamel; this dramatically reduces dental caries (tooth decay). • **Optimal concentration** — the recommended level of fluoride in drinking water for dental protection is 0.5–1.0 parts per million (ppm); below this threshold the protective effect is insufficient, while above 1.5 ppm it causes dental fluorosis (white spots or brown mottling of teeth) and above 4 ppm it causes skeletal fluorosis. • Water fluoridation, introduced in the USA in 1945, is considered one of the 10 great public health achievements of the 20th century; toothpaste fluoride supplementation is the modern primary preventive tool. • 💡 Option A (Chlorine) is wrong because chlorine is added to drinking water as a disinfectant to kill pathogens, not to protect teeth; Option B (Calcium) is wrong because calcium strengthens bones and teeth structurally but does not have the specific anti-decay protective mechanism that fluoride provides; Option C (Sodium) is wrong because sodium has no documented role in preventing tooth decay.

Correct Answer: D. Vitamin E

• **Vitamin E** = Vitamin E was named 'tocopherol' from the Greek 'tokos' (childbirth) specifically because its discovery in 1922 arose from experiments showing that rats fed a Vitamin E-deficient diet became infertile; it is essential for normal spermatogenesis in males and for maintaining healthy pregnancies in females by protecting placental membranes from oxidative damage. • **Antioxidant protection of reproductive tissues** — the gonads and developing embryo are particularly vulnerable to free radical damage because of high lipid content in cell membranes; Vitamin E's role as the primary fat-soluble antioxidant makes it indispensable for protecting these tissues. • During pregnancy, adequate Vitamin E is associated with reduced risk of pre-eclampsia and miscarriage; rich sources include nuts, seeds, vegetable oils, and avocado. • 💡 Option A (Vitamin K) is wrong because Vitamin K's primary function is in blood clotting and bone metabolism, with no significant role in reproductive function; Option B (Vitamin D) is wrong because while Vitamin D has some role in hormonal health, it is not the primary vitamin for reproductive system functioning; Option C (Vitamin A) is wrong because while Vitamin A is needed for normal spermatogenesis and embryo development, the specific 'essential for reproduction' vitamin established in classic nutritional science is Vitamin E.