Q.Why cannot vitamin C be stored in our body?
Concept understanding — Water Soluble Vitamin
Water Soluble Vitamins: The First Meeting
Imagine you drop a spoonful of sugar into a glass of water. It dissolves completely, disappears into the liquid, and you can't see it anymore — but it's still there, molecule by molecule, spread evenly throughout the water. That's exactly what "water soluble" means: the substance mixes with water at the molecular level.
Now, a vitamin is a tiny organic compound your body needs in small amounts to function properly — it helps enzymes do their jobs, keeps your skin healthy, helps you see, and so on. Your body cannot make most vitamins on its own, so you must get them from food.
Put the two together: a water soluble vitamin is a vitamin that dissolves in water. This single property — solubility — determines almost everything about how these vitamins behave in your body.
The Precise Statement
Water soluble vitamins are vitamins that dissolve in water, are not stored in significant amounts in the body, and are excreted in urine when consumed in excess. They must be consumed regularly (daily or almost daily) to prevent deficiency.
The group includes the B-complex vitamins (B1, B2, B3, B5, B6, B7, B9, B12) and Vitamin C. That's 9 vitamins total.
Why Solubility Matters So Much
Think about fat. Fat and water don't mix — oil floats on top of water. Fat soluble vitamins (A, D, E, K) behave like oil: they dissolve in fat, get stored in your liver and fatty tissues, and can stay in your body for weeks or months. You don't need them every single day.
Water soluble vitamins are the opposite. Because they dissolve in water, they travel freely in your blood (which is mostly water). But your kidneys are constantly filtering your blood and removing excess water-soluble substances into urine. So if you take more Vitamin C than your body needs right now, the extra gets flushed out within hours.
This does not mean you can take unlimited amounts safely. Very high doses of some water soluble vitamins (especially B6 and niacin/B3) can cause toxicity — just not as easily as fat soluble vitamins.
The Practical Consequences
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You need them frequently — ideally every day. Missing a day won't cause immediate harm, but weeks of low intake will lead to deficiency diseases (scurvy for Vitamin C, beriberi for B1, pellagra for B3, etc.).
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Cooking destroys them — because they dissolve in water, boiling vegetables leaches vitamins into the cooking water. If you throw that water away, you lose the vitamins. Steaming or microwaving with minimal water preserves them better.
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They are fragile — heat, light, and air can break them down. That's why fresh fruits and vegetables lose vitamin content over time.
The Two Families
| Family | Members | Key Role |
|---|---|---|
| B-complex | B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B7 (biotin), B9 (folate), B12 (cobalamin) | Energy metabolism — they help convert food into usable energy |
| Vitamin C | Ascorbic acid | Collagen synthesis, antioxidant, iron absorption |
The B vitamins often work together as a team. A deficiency in one can affect how others function. That's why B-complex supplements contain all eight — they're designed to work in concert.
The Big Picture
Water soluble vitamins are like daily fuel additives — your body uses what it needs right now and discards the rest. They keep your metabolism running, your nerves healthy, your blood cells forming properly, and your immune system strong. Because they don't stick around, you are the steward of your own supply: what you eat today determines what your cells have to work with tomorrow.
Water-soluble vitamins are part of the vitamins section of the NCERT Class 12 Chemistry chapter on biomolecules, and "water soluble vitamins list and deficiency diseases class 12" is a frequently searched short-answer topic in CBSE board exams. This B-complex-and-vitamin-C classification, with its storage and excretion behaviour, is the standard NCERT-aligned answer for this question type.
Why this formula?
Water-Soluble Vitamins: Understanding Why They Behave the Way They Do
Let’s start with the core idea: Water-soluble vitamins are a group of organic compounds that dissolve in water and are not stored in large amounts in the body. The key “formulae” here are not mathematical equations but chemical structures and physiological principles that explain their solubility, absorption, and excretion.
1. Why Are They Water-Soluble? The Chemical Reason
The fundamental “formula” is the presence of polar functional groups (like –OH, –COOH, –NH₂, –C=O) in their molecular structure.
- Polar groups form hydrogen bonds with water molecules.
- Example: Vitamin C (ascorbic acid) Its structure has multiple –OH groups and a lactone ring.
C6H8O6(with 4 –OH groups)
Each –OH can hydrogen-bond with water, making it highly soluble.
Why this matters:
Unlike fat-soluble vitamins (A, D, E, K) which are nonpolar and stored in fatty tissues, water-soluble vitamins dissolve in blood and interstitial fluid. This means they are rapidly absorbed but also quickly excreted by the kidneys.
Key takeaway: Solubility is not magic — it’s a direct consequence of molecular polarity.
2. The “No Storage” Principle: Why Excretion Happens
The body has no specific binding proteins to store most water-soluble vitamins (except B₁₂).
- Once absorbed, they circulate freely in blood.
- Kidneys filter blood continuously.
- If plasma concentration exceeds the renal threshold, excess is excreted in urine.
Derivation of the excretion logic:
Let Cp = plasma concentration of vitamin, T = renal threshold.
- If Cp≤T → all filtered vitamin is reabsorbed.
- If Cp>T → excess (Cp−T) is lost in urine.
Why this holds:
The transport proteins in kidney tubules have a maximum capacity (saturation). Once saturated, the extra vitamin cannot be reabsorbed.
Exam tip: This is why water-soluble vitamins need daily intake — no storage means deficiency can develop in weeks.
3. The B-Complex “Formula”: Coenzyme Activation
Most B vitamins are precursors to coenzymes. The “formula” here is:
Vitamin (inactive)enzymeCoenzyme (active)
Example: Thiamine (B₁) → Thiamine pyrophosphate (TPP)
- Thiamine has a thiazole ring and a pyrimidine ring.
- In the body, it gets phosphorylated (adds two phosphate groups).
- The active form TPP is a coenzyme for decarboxylation reactions (e.g., in Krebs cycle).
Why this matters for exams:
You don’t need to memorize every step — just understand that the vitamin itself is not the active molecule. The body modifies it to create the functional coenzyme.
4. Vitamin C: The Redox “Formula”
Vitamin C (ascorbic acid) acts as a reducing agent. Its key reaction:
Ascorbic acid⇌Dehydroascorbic acid+2H++2e−
Why this holds:
The molecule has an enediol group (–C(OH)=C(OH)–) which can donate electrons.
- In the reduced form (ascorbic acid), it has two –OH groups on adjacent carbons.
- Upon oxidation, these become a diketone (C=O groups).
- This reversible redox pair allows vitamin C to scavenge free radicals and regenerate other antioxidants (like vitamin E).
Key exam point: The ability to donate electrons is why vitamin C is essential for collagen synthesis (proline hydroxylation requires reducing power).
5. Absorption: The “Active Transport” Formula
Water-soluble vitamins are absorbed in the small intestine via specific transporters.
General formula for absorption rate:
Rate=Km+[Vitamin]Vmax⋅[Vitamin]
- Vmax = maximum transport rate (saturation).
- Km = concentration at half-maximal rate.
Why this matters:
At low dietary intake, absorption is efficient. At high doses (supplements), transporters become saturated, and excess is not absorbed — it passes into feces.
Exception: Vitamin B₁₂
B₁₂ requires intrinsic factor (a protein from stomach) for absorption. Without it, even high doses fail — this is why pernicious anemia occurs.
Summary: The Core “Why” Behind Each Formula
| Aspect | Key Formula/Principle | Why It Holds |
|---|---|---|
| Solubility | Polar functional groups (–OH, –COOH) | Hydrogen bonding with water |
| Excretion | Renal threshold saturation | No storage proteins; kidney filters excess |
| Activation | Vitamin → Coenzyme (phosphorylation) | Body modifies structure for catalytic function |
| Redox (C) | Ascorbic acid ↔ Dehydroascorbic acid + 2e⁻ | Enediol group donates electrons reversibly |
| Absorption | Michaelis-Menten kinetics | Transporter saturation limits uptake |
Final exam-ready takeaway:
Water-soluble vitamins are polar, non-stored, coenzyme precursors that follow saturation kinetics in both absorption and excretion. Their chemistry (functional groups) dictates their biology (solubility, transport, and function).
Vitamin C is a water-soluble vitamin, meaning it dissolves in water rather than being stored in fat or the liver.
- Water-soluble vitamins (like C and the B-complex) are not stored in significant amounts because the body uses what it needs and excretes the excess through urine.
- Unlike fat-soluble vitamins (A, D, E, K), which can be stored in fatty tissues and the liver for long periods, vitamin C has no dedicated storage depot.
- The body maintains a small pool of vitamin C in tissues (e.g., adrenal glands, eyes), but once this pool is saturated, any extra is rapidly filtered by the kidneys and lost.
Vitamin C cannot be stored because it is water-soluble and excess is quickly excreted in urine, with no significant body reservoir.
Vitamin C is water-soluble and not stored in the body because it dissolves in blood and is rapidly excreted by the kidneys, unlike fat-soluble vitamins that accumulate in fatty tissues.
The Concept: Water Solubility and Storage
Vitamins are classified into two broad groups based on their solubility — water-soluble and fat-soluble. This isn't just a chemistry detail; it determines how your body handles them.
Fat-soluble vitamins (A, D, E, K) dissolve in fats and can be tucked away in your liver and fatty tissues for months. Your body builds a reserve, like a pantry. Water-soluble vitamins (the B-complex group and vitamin C) dissolve in water. Since your blood and cells are mostly water, these vitamins circulate freely — but they also get flushed out easily through urine. Think of it like pouring a spoonful of sugar into a glass of water: it dissolves, and if you keep pouring water in, the sugar gets diluted and washed away.
Vitamin C (ascorbic acid) is the classic water-soluble vitamin. Your body has no special storage depot for it. Once the blood is saturated, the excess is filtered out by the kidneys and excreted. That's the core reason.
Step-by-Step Reasoning
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Solubility determines transport and storage.
Vitamin C is a small, polar molecule — it dissolves readily in the aqueous environment of blood plasma and cell cytoplasm. It does not bind to fat or get sequestered in lipid-rich tissues. In contrast, a fat-soluble vitamin like vitamin A is carried by lipoproteins and stored in the liver's fat droplets.
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The kidneys act as a threshold regulator.
Your blood maintains a fairly constant level of vitamin C (about 50–80 µmol/L). When you consume more than the body needs, the excess spills into the urine. This is called renal threshold. For vitamin C, the threshold is low — once plasma levels exceed about 80 µmol/L, the kidneys start dumping the surplus. So any extra intake is lost within hours.
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No specialized binding proteins for long-term storage.
Your liver does not produce a specific "vitamin C storage protein" like it does for vitamin A (retinol-binding protein) or iron (ferritin). Without a protein to hold onto it, vitamin C simply circulates and gets cleared.
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Evolutionary context.
Most mammals can synthesize their own vitamin C from glucose. Humans, along with other primates and guinea pigs, lost the enzyme (L-gulonolactone oxidase) needed for this synthesis. Since our ancestors ate plenty of fresh fruits, there was no evolutionary pressure to develop a storage system — constant dietary intake was the norm.
A common mistake is to think that because vitamin C is "essential," the body must store it. In fact, essentiality has nothing to do with storage — it only means the body cannot make it. Many essential nutrients (like most B vitamins) are also water-soluble and not stored.
This is why you need to consume vitamin C daily — ideally from fruits and vegetables. A single orange provides about 70 mg, which is close to the recommended daily intake. Your body's pool turns over in about 2–3 weeks, so deficiency (scurvy) takes that long to develop after you stop eating vitamin C.
Vitamin C cannot be stored in the body because it is water-soluble and is rapidly excreted by the kidneys once blood levels exceed a low threshold, with no specialized storage mechanism available.
Method: Structure–Function Analysis of Water-Soluble Vitamins
Concept: Water-soluble vitamins (like vitamin C and the B-complex) dissolve in water and are not stored in significant amounts in the body. Fat-soluble vitamins (A, D, E, K) are stored in fatty tissues and the liver.
Steps to answer "Why cannot vitamin C be stored?"
Step 1 – Identify the solubility class
Vitamin C (ascorbic acid) is a water-soluble vitamin. It dissolves in the aqueous (water-based) fluids of the body — blood, cytoplasm, interstitial fluid.
Step 2 – Understand the body’s handling of water-soluble substances
The kidneys filter blood continuously. Water-soluble molecules that are not bound to proteins are easily filtered out into urine.
- Fat-soluble vitamins travel with lipoproteins or carrier proteins and are reabsorbed in the kidneys.
- Water-soluble vitamins, including vitamin C, are excreted in urine when blood levels exceed the kidney’s reabsorption capacity (≈1.5–2.0 g/day for vitamin C).
Step 3 – Link to storage sites
The body has no specialized storage compartment for water-soluble vitamins.
- Fat-soluble vitamins are stored in adipose tissue and liver (lipid-rich environments).
- Vitamin C cannot be stored because it remains in water-based compartments and is rapidly lost via urine.
Step 4 – State the biological consequence
Since vitamin C is not stored, it must be consumed regularly in the diet. Excess intake is simply excreted, not saved for later use.
Final Answer (exam-ready)
Vitamin C cannot be stored because it is water-soluble.
Water-soluble vitamins dissolve in body fluids, are not bound to storage proteins, and are rapidly excreted by the kidneys when levels exceed the body’s immediate needs. Unlike fat-soluble vitamins, there is no significant depot (like adipose tissue or liver) for water-soluble vitamins. Hence, regular dietary intake is essential.
Key takeaway: Solubility determines storage — water-soluble = no storage; fat-soluble = storage possible.
Here are the most common mistakes students make when answering "Why cannot vitamin C be stored in our body?" and how to avoid each.
Mistake 1: Confusing "Water-Soluble" with "Fat-Soluble" Properties
- The Mistake: Students often say "Vitamin C cannot be stored because it is water-soluble." While this is partially true, it is an incomplete answer. They forget to contrast it with fat-soluble vitamins (A, D, E, K) which can be stored in the liver and adipose tissue.
- Why it’s wrong: The examiner wants the mechanism. Simply saying "it's water-soluble" doesn't explain why the body doesn't hold onto it.
- How to Avoid: Always mention the key difference:
- Water-soluble vitamins (like C and B-complex) dissolve in water. Excess amounts are excreted in urine by the kidneys.
- Fat-soluble vitamins dissolve in fat and are stored in the liver and fatty tissues.
- Correct Answer Structure: "Vitamin C is water-soluble. Unlike fat-soluble vitamins, it is not stored in significant amounts in the body. Any excess is rapidly filtered by the kidneys and excreted in urine."
Mistake 2: Forgetting the Role of the Kidneys
- The Mistake: Students stop at "it is water-soluble" and don't mention the renal threshold or kidney excretion.
- Why it’s wrong: The body could theoretically store some, but the kidneys actively remove excess water-soluble vitamins to maintain balance.
- How to Avoid: Add this specific detail:
- "The kidneys have a low renal threshold for vitamin C. Once blood levels are saturated, the excess is quickly filtered out and lost in urine."
- Memory Tip: Think of the kidneys as a "drain" that opens when the vitamin C "bucket" is full.
Mistake 3: Saying "Vitamin C is Never Stored"
- The Mistake: Claiming the body has zero storage capacity for vitamin C.
- Why it’s wrong: The body does have a small pool of vitamin C in tissues (e.g., adrenal glands, white blood cells, eyes). It's just that this pool is very small (about 1.5–2 grams) and gets depleted quickly.
- How to Avoid: Use precise language:
- "Vitamin C is not stored in large amounts." or "It has a limited storage capacity."
- Correct phrasing: "The body cannot store vitamin C in significant quantities because it is water-soluble and excess is excreted. Only a small amount is maintained in tissues."
Mistake 4: Ignoring the "Why" – Evolutionary & Chemical Reason
- The Mistake: Giving only a biological answer (excretion) without the chemical or evolutionary reason.
- Why it’s wrong: The deeper reason is that humans (and other primates) lost the gene for the enzyme L-gulonolactone oxidase, which is needed to synthesize vitamin C from glucose. So we must get it from diet, and we cannot store it because our ancestors didn't need to (they ate fruits constantly).
- How to Avoid: Add this for a top-scoring answer:
- "Humans cannot synthesize vitamin C due to a mutation in the gene for L-gulonolactone oxidase. Therefore, we rely entirely on dietary intake. Because it is water-soluble and not stored, we need a regular daily supply."
Mistake 5: Mixing Up Vitamin C with B-Complex Vitamins
- The Mistake: Treating all water-soluble vitamins as identical in storage.
- Why it’s wrong: While both are water-soluble, Vitamin B12 is an exception — it can be stored in the liver for years. Vitamin C cannot.
- How to Avoid: Remember the B12 exception:
- "Most water-soluble vitamins (like C and B-complex except B12) are not stored. Vitamin B12 is stored in the liver because it binds to specific proteins."
- Exam Tip: If the question is specifically about Vitamin C, don't bring up B12 unless comparing.
Quick Revision Table: How to Avoid Mistakes
| Common Mistake | Correct Approach | Key Phrase to Use |
|---|---|---|
| "It's water-soluble" (vague) | Contrast with fat-soluble vitamins | "Unlike fat-soluble vitamins (A, D, E, K)..." |
| Forgetting kidneys | Mention renal excretion | "...excess is filtered by kidneys and excreted in urine." |
| "Never stored" | Say "limited storage" | "...not stored in significant amounts." |
| No chemical reason | Mention missing enzyme | "Humans lack L-gulonolactone oxidase..." |
| Confusing with B12 | Note B12 is an exception | "Vitamin B12 is stored; Vitamin C is not." |
Final Tip for Exams: Always start your answer with the definition: "Vitamin C (ascorbic acid) is a water-soluble vitamin. Therefore, it cannot be stored in the body in large amounts. Any excess is rapidly excreted by the kidneys, so a daily intake is essential."
- CBSE 2026Set ANNUAL1 markMCQQ.Vitamin C is(a) Water soluble(b) Fat soluble(c) Soluble in both(d) None of these
›Reveal solutionSolution
Vitamins are classified as either fat-soluble (A, D, E, K) or water-soluble (B-complex and C); Vitamin C belongs to the water-soluble group.
Vitamin C (ascorbic acid) dissolves in water due to its polar hydroxyl-rich structure, and like the B-complex vitamins, it is not stored in significant amounts in the body - excess is excreted in urine, and it must be replenished regularly through diet. This is in contrast to the fat-soluble vitamins A, D, E, and K, which dissolve in lipids and can be stored in fatty tissue.
✓Final answer(a) Water soluble.
- CBSE 2025Set D1 markMCQQ.Water soluble vitamin is(a) Vitamin E(b) Vitamin D(c) Vitamin K(d) Vitamin B
›Reveal solutionSolution
Vitamins B and C are water soluble; A, D, E, K are fat soluble — so the answer is Vitamin B.
Vitamins are classified by their solubility:
- Water soluble: vitamin B-complex (B1, B2, B6, B12 etc.) and vitamin C. These are not stored in the body and must be supplied regularly in diet; excess is excreted in urine.
- Fat (oil) soluble: vitamins A, D, E and K. These are stored in liver and adipose tissue.
Among the options, vitamins E, D and K are all fat soluble; only vitamin B is water soluble.
✓Final answer(D) Vitamin B is water soluble.
- CBSE 2025Set ANNUAL1 markQ.Fill in the blank: Water soluble Vitamins are Vitamin B and ________.
›Reveal solutionSolution
The water-soluble vitamins are vitamin B-complex and vitamin C; the rest (A, D, E, K) are fat-soluble.
Vitamins are classified by solubility:
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Fat-soluble: A, D, E, K (stored in the body's fatty tissue and liver).
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Water-soluble: B-complex vitamins and Vitamin C (not stored in the body to a large extent; excess is excreted in urine, so regular dietary intake is required).
✓Final answerVitamin C.
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- CBSE 2025Set ANNUAL1 markQ.Write the chemical name of Vitamin C.
›Reveal solutionSolution
Vitamin C is L-ascorbic acid, a water-soluble vitamin.
Vitamin C is chemically known as ascorbic acid. It is a water-soluble vitamin (unlike A, D, E, K which are fat-soluble) and is not stored in the body, so it must be supplied regularly through diet (citrus fruits, amla, etc.). Its deficiency causes scurvy.
✓Final answerAscorbic acid.
- CBSE 2023Set 56/3/11 markMCQQ.Which of the following vitamins is water soluble? (A) Vitamin A (B) Vitamin D (C) Vitamin E (D) Vitamin C
›Reveal solutionSolution
Vitamins divide into fat-soluble (A, D, E, K) and water-soluble (B-complex and C) based on their chemical structure and solubility. Vitamin C is the only water-soluble option here.
Understanding vitamin solubility
Vitamins fall into two fundamental categories determined by their molecular architecture. Fat-soluble vitamins possess long hydrocarbon chains or ring structures that make them nonpolar—they dissolve in lipids and organic solvents. Water-soluble vitamins, by contrast, carry multiple hydroxyl groups (−OH) or other polar functional groups that form hydrogen bonds with water molecules.
This distinction isn't academic trivia; it governs how your body handles each vitamin. Fat-soluble vitamins (A, D, E, K) get stored in liver and adipose tissue, accumulating over time. Water-soluble vitamins (the B-complex family and vitamin C) cannot be stored in significant amounts—excess quantities are excreted in urine, which is why you need regular dietary intake.
Analyzing each option
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Vitamin A (retinol): A long-chain alcohol with a β-ionone ring and an isoprenoid tail. Completely hydrophobic. Stored in the liver as retinyl esters. Fat-soluble.
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Vitamin D (calciferol): A steroid derivative with four fused rings and a side chain. Synthesized in skin from cholesterol upon UV exposure. Stored in fat tissue. Fat-soluble.
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Vitamin E (tocopherol): Features a chromanol ring attached to a long phytyl tail (16 carbons). Acts as a lipid-phase antioxidant in cell membranes. Fat-soluble.
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Vitamin C (ascorbic acid): A six-carbon lactone with four hydroxyl groups and an enediol structure. The multiple −OH groups make it highly polar. Dissolves readily in aqueous solutions. Water-soluble.
TipRemember the mnemonic "ADEK" for fat-soluble vitamins. Everything else—particularly the B vitamins and C—is water-soluble.
Watch outDon't confuse "essential" with "fat-soluble." All vitamins are essential nutrients, but only A, D, E, and K are fat-soluble. Vitamin C's essentiality (preventing scurvy) doesn't tell you about its solubility.
The chemical reality is straightforward: ascorbic acid's structure is dominated by polar groups that interact favorably with water's hydrogen-bonding network, while vitamins A, D, and E are built from hydrocarbon frameworks that repel water.
✓Final answerThe correct option is (D) Vitamin C.
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- CBSE 2023Set F1 markMCQQ.Which of the following vitamins are soluble in water?(a) A and B(b) C and D(c) B and C(d) A and D
›Reveal solutionSolution
The B-complex vitamins and vitamin C are water-soluble; A, D, E and K are fat-soluble.
Vitamins are grouped by solubility:
- Water-soluble: the B-group (B1, B2, B6, B12, etc.) and vitamin C. Because they are not stored appreciably in the body, they must be supplied regularly in the diet and are excreted in urine.
- Fat-soluble: A, D, E and K, which are stored in the liver and fatty tissue.
Hence the water-soluble pair among the choices is B and C.
✓Final answer(c) B and C.
- CBSE 2020Set ANNUAL1 markQ.Give an example for water soluble vitamin.
›Reveal solutionSolution
Vitamin C (ascorbic acid) — and the B-complex vitamins — are water-soluble; vitamin C is a standard example.
Concept. Vitamins are classified by solubility into fat-soluble (A, D, E, K) and water-soluble (B-group and C). Water-soluble vitamins dissolve in water, are not stored in the body, and are regularly excreted in urine, so they must be supplied continuously in the diet.
Example. Vitamin C (ascorbic acid) is a well-known water-soluble vitamin; its deficiency causes scurvy. The B-complex vitamins (e.g. B1 thiamine, B2 riboflavin) are also water-soluble.
✓Final answerVitamin C (ascorbic acid) is an example of a water-soluble vitamin (any vitamin-B, e.g. B1, is also correct).
- CBSE 2019Set ANNUAL1 markQ.Beri-beri occurs due to the deficiency of which vitamin?
›Reveal solutionSolution
Beri-beri is a nerve and cardiovascular disorder caused specifically by a deficiency of vitamin B1 (thiamine).
Thiamine (vitamin B1) is a water-soluble B-vitamin required as a coenzyme in carbohydrate metabolism. Its prolonged deficiency impairs nerve conduction and heart function, producing the disease beri-beri, characterised by weakness, nerve damage (polyneuritis) and in severe cases heart failure. This is why thiamine-fortified/polished-rice diets historically caused outbreaks of beri-beri in populations relying heavily on milled rice.
✓Final answerVitamin B1 (Thiamine).
- CBSE 2018Set ANNUAL1 markMCQQ.Which among the given vitamins is water soluble ?(a) A(b) B(c) D(d) E
›Reveal solutionSolution
Vitamins are classified as fat-soluble (A, D, E, K) or water-soluble (B-complex and C); among the given options, vitamin B is water soluble.
Vitamins A, D, E and K are fat-soluble — they dissolve in fats/oils and are stored in the body's fatty tissue and liver.
Vitamins of the B group (B-complex) and vitamin C are water-soluble — they dissolve in water and, being generally not stored in the body, must be supplied regularly through diet; excess amounts are excreted in urine.
Among the given options (A, B, D, E), only B is water soluble.
✓Final answer(b) B — vitamin B is water soluble.
- CBSE 2017Set ANNUAL1 markQ.Fresh tomatoes are a better source of vitamin C than those which have been stored for some time. Why ?
›Reveal solutionSolution
Vitamin C degrades on storage because it is a water-soluble vitamin that is easily oxidised.
Vitamin C (ascorbic acid) belongs to the water-soluble vitamins, which — unlike the fat-soluble ones — are not stored in the body and, importantly here, are also chemically unstable outside the body: they are readily decomposed by exposure to heat, light, and atmospheric oxygen (oxidation). As tomatoes are stored over time, their vitamin C content is progressively oxidised/degraded, so freshly picked tomatoes retain significantly more vitamin C than those stored for a period.
✓Final answerBecause vitamin C is water-soluble and easily oxidised/decomposed by heat, light and air, its content falls during storage.
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