Vitamins and Coenzymes Practice Questions

Q: A 25-year-old alcoholic presented with edema, hypertension, ocular disturbance, and changes in mental state. A diagnosis of high output cardiac failure was made with Wet Beri Beri. This condition is due to a deficiency of which vitamin?

Vitamin B1. Vitamin B1 - The constellation of **edema**, **hypertension**, **ocular disturbances**, and **mental status changes** in an **alcoholic** patient with **high-output cardiac failure** (Wet Beri Beri) is a classic presentation of **thiamine (Vitamin B1) deficiency** [2], [3]. - **Thiamine** is crucial for **carbohydrate metabolism** and **neurological function**, and a deficiency can lead to severe cardiovascular and neurological dysfunction, especially in chronic alcoholics due to poor absorption and increased metabolic demand [1], [3]. Vitamin B3 - Deficiency of Vitamin B3 (niacin) causes **pellagra**, characterized by the "4 D's": **dermatitis**, **diarrhea**, **dementia**, and death. - While it can cause psychiatric symptoms (dementia), it does not directly lead to the specific cardiovascular manifestations of high-output cardiac failure as seen in Wet Beri Beri. Vitamin B6 - Deficiency of Vitamin B6 (pyridoxine) can result in **peripheral neuropathy**, **anemia**, and **seizures**. - It is not directly linked to the cardiac and edematous symptoms characteristic of Wet Beri Beri. Vitamin B9 - Deficiency of Vitamin B9 (folate) primarily causes **megaloblastic anemia** and can lead to **neural tube defects** in developing fetuses. - While it can manifest with fatigue and weakness due to anemia, it does not typically present with the acute cardiovascular and neurological syndrome described.

Q: Which vitamin deficiency is associated with night blindness?

Vit. A. ***Vitamin A*** - **Vitamin A deficiency is THE classic cause of night blindness (nyctalopia)**, one of the earliest signs of deficiency - Vitamin A is essential for synthesis of **rhodopsin**, the photopigment in retinal rod cells responsible for vision in dim light - Deficiency leads to impaired dark adaptation and progressive loss of night vision - Other manifestations include **xerophthalmia, Bitot's spots, and keratomalacia** - This is a high-yield fact for NEET-PG examinations *Riboflavin (Vitamin B2)* - Riboflavin deficiency causes **oral-ocular-genital syndrome** - Clinical features include **angular stomatitis, cheilosis, glossitis, seborrheic dermatitis** - Eye manifestations include **corneal vascularization and photophobia**, NOT night blindness - Does NOT cause night blindness as a primary symptom *Thiamine (Vitamin B1)* - Thiamine deficiency causes **Beriberi** (wet and dry forms) and **Wernicke-Korsakoff syndrome** - Characterized by peripheral neuropathy, cardiac dysfunction, and CNS manifestations - Does NOT cause night blindness *Biotin (Vitamin B7)* - Biotin deficiency is rare and causes **dermatitis, alopecia, conjunctivitis** - Also causes neurological symptoms in severe deficiency - Does NOT cause night blindness

Q: Which vitamin/nutrient toxicity is associated with excessive sweating?

Choline. ***Choline*** - **Excessive sweating** is a recognized symptom of choline toxicity, often accompanied by a **fishy body odor**, hypotension, and gastrointestinal distress. - Choline plays a role in various metabolic pathways, and high doses can overwhelm these systems, leading to adverse effects. *Biotin* - **Biotin toxicity** is extremely rare, even at very high doses; there are no well-documented cases of adverse effects from excessive intake. - Symptoms like excessive sweating are not associated with biotin overdose. *Folic acid* - While high doses of **folic acid** can mask a **vitamin B12 deficiency**, side effects like gastrointestinal upset or sleep disturbances are rare. - Excessive sweating is **not a characteristic symptom** of folic acid toxicity. *Niacin (Vitamin B3)* - High doses of niacin, especially its nicotinic acid form, are well-known to cause **flushing, itching, and liver toxicity**. - While skin effects are common with niacin toxicity, **excessive sweating** as a primary symptom is not typically reported.

Q: Dietary deficiency of which vitamin is considered extremely rare?

Vitamin E. ***Vitamin E*** - **Vitamin E deficiency** is exceptionally rare because it is a **fat-soluble vitamin** stored in the body and is widely available in many common foods. - Symptoms of deficiency, when they do occur, are usually seen in individuals with severe **malabsorption syndromes** or genetic abnormalities affecting its metabolism. *Vitamin B6* - **Vitamin B6 deficiency** can occur, especially in individuals with **alcoholism**, those taking certain medications, or with certain chronic diseases. - It can manifest with neurological symptoms, such as **neuropathy** and **seizures**, as well as dermatological issues. *Thiamine* - **Thiamine (Vitamin B1) deficiency** is a known problem in regions with poor nutrition and in chronic alcoholics. - It leads to conditions like **beriberi** (wet and dry) and **Wernicke-Korsakoff syndrome**, affecting the cardiovascular and nervous systems. *Vitamin D* - **Vitamin D deficiency** is common globally, particularly in populations with limited sun exposure or inadequate dietary intake. - It can cause **rickets** in children and **osteomalacia** in adults, impacting bone health.

Q: Which of the following is NOT a manifestation of vitamin E deficiency?

Autonomic dysfunction. ***Autonomic dysfunction*** - **Autonomic dysfunction** is not typically associated with vitamin E deficiency. Instead, it is commonly seen in conditions like **diabetes mellitus**, Parkinson's disease, or certain inherited neuropathies. - Vitamin E primarily acts as an **antioxidant** and is crucial for neurological and red blood cell health. *Hemolytic anemia* - Vitamin E is an **antioxidant** that protects red blood cell membranes from **oxidative damage**. - Its deficiency can lead to increased fragility and **hemolysis** of red blood cells, resulting in hemolytic anemia, particularly in premature infants. *Posterior column abnormalities* - Vitamin E deficiency can cause **neurological dysfunction** due to oxidative damage to neuronal membranes. - This often manifests as degeneration of the **posterior columns** of the spinal cord, leading to impaired proprioception and vibratory sensation. *Cerebellar ataxia* - The **cerebellum** is highly susceptible to oxidative stress, and vitamin E deficiency can lead to damage in this area. - This damage results in **ataxia**, characterized by impaired coordination, balance, and gait disturbances.

Q: Dermatitis may be a clinical manifestation of deficiency states of all of the following nutrients except -

Thiamine. ***Thiamine*** - A deficiency in **thiamine (vitamin B1)** primarily affects the nervous and cardiovascular systems, leading to conditions like **beriberi**, characterized by neuropathy, heart failure, and Wernicke-Korsakoff syndrome. - Dermatitis is **not a typical or direct clinical manifestation** of thiamine deficiency. *Biotin* - **Biotin (vitamin B7)** deficiency can cause **dermatitis**, often described as a scaly, erythematous rash around the eyes, nose, and mouth. - Hair loss (**alopecia**) and **neurological symptoms** are also associated with biotin deficiency. *Niacin* - **Niacin (vitamin B3)** deficiency leads to **pellagra**, classically presenting with the "3 Ds": **dermatitis**, **diarrhea**, and **dementia**. - The dermatitis in pellagra is typically symmetrical and photosensitive, affecting sun-exposed areas. *Pyridoxine* - **Pyridoxine (vitamin B6)** deficiency can result in **seborrheic dermatitis-like rash**, especially around the eyes, nose, and mouth. - Other symptoms include **glossitis**, **cheilosis**, and **neurological disturbances** like peripheral neuropathy.

Q: Which nutrient is lost maximally in polished rice?

Thiamine. ***Thiamine*** - **Polishing rice** removes the outer layers (bran and germ), which are rich in **thiamine (vitamin B1)**. - Significant loss of thiamine can lead to **beriberi**, characterized by neurological and cardiovascular symptoms. *Proteins* - While some protein is lost during milling, the primary nutritional loss in polished rice is not protein. - The germ and aleurone layer contain some protein, but the main carbohydrate-rich endosperm remains. *Ascorbic acid* - **Ascorbic acid (Vitamin C)** is not a significant nutrient in rice, so its loss during polishing is negligible. - Rice is not a primary dietary source of vitamin C. *Calcitriol* - **Calcitriol** is the active form of **vitamin D**, and rice does not naturally contain vitamin D. - Therefore, it cannot be lost during the polishing process.

Q: Vitamin D absorption is decreased by ?

Fat malabsorption. ***Fat malabsorption*** - **Vitamin D** is a **fat-soluble vitamin**, meaning it requires dietary fat for proper absorption in the small intestine. - Conditions causing **fat malabsorption**, such as **cystic fibrosis**, **celiac disease**, or **pancreatic insufficiency**, significantly reduce the uptake of vitamin D. *Proteins* - **Proteins** do not directly decrease vitamin D absorption; in fact, some dietary proteins can enhance vitamin D binding and transport in the bloodstream. - Their primary role is in structural and enzymatic functions, not impeding fat-soluble vitamin uptake. *Acid* - **Gastric acid** is important for the absorption of some nutrients, but it generally does not directly hinder the absorption of **fat-soluble vitamins** like vitamin D. - Conditions like **achlorhydria** primarily affect the absorption of minerals and vitamin B12, rather than vitamin D. *Lactose* - **Lactose** is a sugar found in milk, and its malabsorption (lactose intolerance) primarily causes gastrointestinal symptoms like bloating and diarrhea. - It does not directly interfere with the absorption of **fat-soluble vitamins**; rather, it affects carbohydrate digestion.

Q: Which fat-soluble vitamin is most classically known for its steroid hormone-like action through nuclear receptors?

Vitamin D. ***Correct Answer: Vitamin D*** - **Vitamin D** (specifically its active form, **calcitriol** or **1,25-dihydroxyvitamin D₃**) is the **most classically recognized** fat-soluble vitamin that functions as a **steroid hormone** - It binds to the **vitamin D receptor (VDR)**, which is a member of the **nuclear receptor superfamily** - This VDR-calcitriol complex acts as a transcription factor, regulating gene expression involved in **calcium and phosphate homeostasis**, bone metabolism, skeletal development, and immune function - The mechanism is analogous to classic steroid hormones like cortisol, estrogen, and testosterone *Incorrect: Vitamin A* - **Vitamin A** (as **retinoic acid**) also interacts with nuclear receptors (**retinoic acid receptors - RARs** and **retinoid X receptors - RXRs**) to regulate gene transcription - However, Vitamin A is **most classically associated** with vision (rhodopsin in retinal photoreceptors), epithelial cell differentiation, embryonic development, and immune function - While it does have nuclear receptor-mediated actions, **Vitamin D is more prominently described** as having steroid hormone-like activity in standard medical education *Incorrect: Vitamin K* - **Vitamin K** functions primarily as a **cofactor for γ-glutamyl carboxylase**, an enzyme that catalyzes post-translational modification of glutamate residues to γ-carboxyglutamate (Gla) - Essential for the synthesis of **clotting factors** (II, VII, IX, X, protein C, protein S) and bone proteins (osteocalcin) - Does **not** act through nuclear receptors or function as a steroid hormone *Incorrect: Vitamin E* - **Vitamin E** (α-tocopherol) is a powerful **lipid-soluble antioxidant** that protects cell membranes from oxidative damage by scavenging free radicals - Functions primarily through its **antioxidant properties**, not through nuclear receptor binding - Does **not** have steroid hormone-like actions

Question 1

A 25-year-old alcoholic presented with edema, hypertension, ocular disturbance, and changes in mental state. A diagnosis of high output cardiac failure was made with Wet Beri Beri. This condition is due to a deficiency of which vitamin?

Accepted Answer

Vitamin B1

Answer

Vitamin B3

Answer

Vitamin B6

Answer

Vitamin B9

Question 2

Which vitamin deficiency is associated with night blindness?

Accepted Answer

Vit. A

Answer

Biotin

Answer

Thiamine

Answer

Riboflavin

Question 3

Which of the following statements about vitamin K is correct?

Accepted Answer

Prolonged use of antimicrobials can lead to vitamin K deficiency.

Answer

All of the options are incorrect.

Answer

It is an anticoagulant.

Answer

The recommended dietary allowance (RDA) for adults is 500-600 micrograms.

Question 4

Which vitamin/nutrient toxicity is associated with excessive sweating?

Accepted Answer

Choline

Answer

Biotin

Answer

Folic acid

Answer

Niacin (Vitamin B3)

Question 5

Dietary deficiency of which vitamin is considered extremely rare?

Accepted Answer

Vitamin E

Answer

Thiamine

Answer

Vitamin B6

Answer

Vitamin D

Question 6

Which of the following is NOT a manifestation of vitamin E deficiency?

Accepted Answer

Autonomic dysfunction

Answer

Posterior column abnormalities

Answer

Cerebellar ataxia

Answer

Hemolytic anemia

Question 7

Dermatitis may be a clinical manifestation of deficiency states of all of the following nutrients except -

Accepted Answer

Thiamine

Answer

Biotin

Answer

Niacin

Answer

Pyridoxine

Question 8

Which nutrient is lost maximally in polished rice?

Accepted Answer

Thiamine

Answer

Proteins

Answer

Ascorbic acid

Answer

Calcitriol

Question 9

Vitamin D absorption is decreased by ?

Accepted Answer

Fat malabsorption

Answer

Proteins

Answer

Acid

Answer

Lactose

Question 10

Which fat-soluble vitamin is most classically known for its steroid hormone-like action through nuclear receptors?

Accepted Answer

Vitamin D

Answer

Vitamin K

Answer

Vitamin A

Answer

Vitamin E

Vitamins and Coenzymes — MCQs

Vitamins and Coenzymes — MCQs

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