Nutrition and Metabolism — MCQs

Nutrition and Metabolism Indian Medical PG Practice Questions and MCQs

Question 291: Which deficiency is most likely in a patient with delayed wound healing and alopecia?

A. Calcium
B. Zinc (Correct Answer)
C. Copper
D. Vitamin D

Explanation: ***Zinc*** - **Zinc** is vital for numerous enzymatic reactions involved in protein synthesis, immune function, and cell membrane stability, impairment of which severely delays **wound healing** and tissue repair. - **Alopecia** is a classic dermatologic finding in zinc deficiency, often accompanied by **acrodermatitis enteropathica** (perioral and acral cutaneous lesions). - The combination of delayed wound healing and alopecia is highly characteristic of zinc deficiency. *Copper* - Copper deficiency typically manifests with **microcytic anemia** (refractory to iron) and **neutropenia** due to its role in iron metabolism and hematopoiesis. - While severe copper deficiency can rarely cause hair abnormalities (often described as "kinky hair" or hypopigmentation), it does not characteristically cause the combination of delayed wound healing and alopecia. - Neurological manifestations (myelopathy, peripheral neuropathy) are more prominent in copper deficiency. *Calcium* - Calcium deficiency primarily affects **bone health** (osteoporosis, osteomalacia) and **neuromuscular function** (tetany, paresthesias, seizures). - It does not typically cause delayed wound healing or alopecia. *Vitamin D* - Vitamin D deficiency mainly causes **musculoskeletal problems** (rickets in children, osteomalacia in adults, bone pain, muscle weakness). - While it has roles in immune function, it is not classically associated with the specific combination of delayed wound healing and alopecia.

Question 292: Which of the following is not a microelement?

A. Calcium (Correct Answer)
B. Copper
C. Selenium
D. Zinc

Explanation: ***Calcium***- Calcium is classified as a **macroelement** (or major mineral) because the body requires it in large quantities, often exceeding 100 mg daily.- It is essential for **bone mineralization**, muscle contraction, and is the most abundant mineral in the human body.*Copper*- Copper is a **microelement** (or trace mineral) and is required in amounts less than 100 mg per day.- It functions as a cofactor for several antioxidant and electron transport enzymes, crucial for **iron metabolism**.*Zinc*- Zinc is a **microelement** vital for immune function, protein synthesis, and is required in trace daily amounts.- It is a necessary cofactor for the function of over 300 enzymes, playing a key role in **gene expression** and wound healing.*Selenium*- Selenium is a **microelement** known for its antioxidant properties and is required in minute quantities (micrograms) daily.- It is structurally central to **glutathione peroxidase**, an enzyme that protects cells from oxidative damage.

Question 293: Dietary fibres have :

A. catabolic effect
B. sometimes anabolic and sometimes catabolic effect, depending on the type
C. anabolic effect
D. no metabolic effect (Correct Answer)

Explanation: ***no metabolic effect*** - Dietary fibers are **indigestible polysaccharides** that cannot be broken down by human digestive enzymes. - Humans lack enzymes like **cellulase** necessary to hydrolyze the β-glycosidic bonds in dietary fiber. - Dietary fibers pass through the gastrointestinal tract **without being metabolized** by human cells, meaning they do not participate in anabolic or catabolic pathways. - While gut bacteria can ferment some fibers producing short-chain fatty acids (SCFAs), this is **bacterial metabolism**, not human metabolism. - The physiological effects of fiber (improved bowel motility, reduced cholesterol absorption, glycemic control) are **mechanical and physicochemical**, not metabolic. *catabolic effect* - Catabolic processes involve **breakdown of molecules with energy release** (e.g., glycolysis, lipolysis). - Dietary fibers cannot undergo catabolism in humans because we lack the enzymes to break them down. - The fermentation by gut bacteria is not human catabolism. *anabolic effect* - Anabolic processes involve **synthesis of complex molecules** from simpler ones (e.g., protein synthesis, glycogenesis). - Dietary fibers are not absorbed or incorporated into human tissues, so they cannot participate in anabolic reactions. *sometimes anabolic and sometimes catabolic effect, depending on the type* - Regardless of fiber type (soluble or insoluble), **all dietary fibers remain non-metabolizable** by human enzymes. - Neither type undergoes anabolic or catabolic metabolism in human cells.

Question 294: Which one of the following is the major contributor to the total energy intake, in terms of energy provided, in an average Indian diet?

A. Proteins
B. Fats
C. Carbohydrates (Correct Answer)
D. Vitamins

Explanation: ***Carbohydrates*** - **Carbohydrates** are the primary source of energy in an average Indian diet, mainly from staple foods like rice, wheat, and millets. - They provide approximately **4 kcal/gram** and constitute the bulk of daily caloric intake for most individuals in India. *Proteins* - While essential for growth and repair, **proteins** are typically consumed in smaller quantities than carbohydrates in the average Indian diet. - They provide about **4 kcal/gram**, but total protein intake often contributes less to overall energy compared to carbohydrates. *Fats* - **Fats** are the most energy-dense macronutrient, providing **9 kcal/gram**, but their overall contribution to total energy intake is usually less than that of carbohydrates. - The typical Indian diet emphasizes carbohydrate-rich vegetarian staples, with fats often used for cooking rather than forming the primary energy source. *Vitamins* - **Vitamins** are micronutrients essential for various bodily functions and do not provide any direct energy (calories). - They are crucial for metabolic processes but are not considered a source of energy intake.

Question 295: Acrodermatitis enteropathica is an autosomal recessive metabolic disorder which affects the absorption of which one of the following micronutrients?

A. Zinc (Correct Answer)
B. Selenium
C. Iron
D. Iodine

Explanation: ***Correct: Zinc*** - **Acrodermatitis enteropathica** is an autosomal recessive disorder caused by a defect in the absorption of **zinc** from the intestines (due to mutations in the *SLC39A4* gene encoding the ZIP4 zinc transporter). - This leads to the characteristic clinical triad: periorificial and acral **dermatitis**, **alopecia**, and **diarrhea**. - Treatment involves lifelong zinc supplementation. *Incorrect: Selenium* - **Selenium** deficiency can lead to **Keshan disease** (cardiomyopathy) and **Kashin-Beck disease** (osteoarthropathy), which are distinct from acrodermatitis enteropathica. - Symptoms related to selenium deficiency do not typically include the prominent dermatological and gastrointestinal features seen in acrodermatitis enteropathica. *Incorrect: Iron* - **Iron** deficiency primarily causes **anemia** and symptoms like fatigue, pallor, and pica. - While iron is a crucial micronutrient, its malabsorption does not result in the specific skin, hair, and gastrointestinal manifestations of acrodermatitis enteropathica. *Incorrect: Iodine* - **Iodine** deficiency is strongly associated with **goiter** and various thyroid dysfunctions, including **hypothyroidism** and **cretinism**. - These conditions are entirely different from the syndrome of acrodermatitis enteropathica, which is characterized by zinc malabsorption.

Question 296: Which food proteins among the following are considered to be the best and are used in nutritional studies as 'reference protein' ?

A. Milk proteins
B. Legume proteins
C. Wheat proteins
D. Egg proteins (Correct Answer)

Explanation: ***Egg proteins*** - **Egg proteins** provide all **essential amino acids** in proportions that closely match human requirements, making them a **high-quality protein**. - Due to their excellent amino acid profile and high digestibility, **egg proteins** are often used as a **reference protein** in nutritional studies to evaluate the biological value of other proteins. *Milk proteins* - While **milk proteins** (casein and whey) are generally considered high-quality, their amino acid profile is not as perfectly balanced for human needs as egg protein. - They are commonly used as a reference for assessing protein quality, but **egg protein** often serves as the gold standard for comparison. *Legume proteins* - **Legume proteins** are typically deficient in **methionine and cysteine**, essential amino acids, making them an incomplete protein when consumed alone. - Their overall **biological value** is lower than animal proteins, and they are not considered a reference protein. *Wheat proteins* - **Wheat proteins** (gluten) are deficient in the **essential amino acid lysine**. - They have a lower **biological value** and are not as easily digestible as animal proteins, thus not suitable as a reference protein.

Question 297: Consider the following milks : 1. Buffalo milk 2. Cow milk 3. Goat milk 4. Human milk What is the correct order (from highest to lowest) with regard to fat content per 100 gm in the milk?

A. 2 → 1 → 4 → 3
B. 1 → 3 → 4 → 2 (Correct Answer)
C. 1 → 2 → 3 → 4
D. 4 → 2 → 3 → 1

Explanation: ***1 → 3 → 4 → 2*** - **Buffalo milk** generally has the highest fat content (around 6-7%), followed by **goat milk** (4.1%), **human milk** (3.8-4.5%), and finally **cow milk** (3.2-3.8%). - This order reflects the typical fat percentage found in these types of milk, which varies based on breed, diet, and individual factors. *2 → 1 → 4 → 3* - This order incorrectly places cow milk as having the highest fat content and goat milk as the lowest, which is not accurate. - Cow milk typically has a lower fat percentage than buffalo milk. *1 → 2 → 3 → 4* - While buffalo milk is correctly identified as having the highest fat content, this order incorrectly places cow milk above goat milk and human milk. - Human milk and goat milk generally have higher fat content than cow milk. *4 → 2 → 3 → 1* - This order places human milk as having the highest fat content, which is incorrect as buffalo milk consistently has a higher fat content. - It also reverses the correct order for buffalo and cow milk.

Question 298: Consider the protein content of the following food items (in terms of grams per 100 grams of food) : 1. Cow milk 2. Meat 3. Soya bean 4. Sugar What is the correct descending order (highest to lowest) of protein content?

A. 2 → 3 → 4 → 1
B. 3 → 2 → 1 → 4 (Correct Answer)
C. 2 → 1 → 3 → 4
D. 3 → 1 → 2 → 4

Explanation: ***Correct Option: 3 → 2 → 1 → 4*** - **Soya bean** has the highest protein content at approximately **36-40 grams per 100 grams**, making it one of the richest plant-based protein sources - **Meat** (chicken, beef) follows with **20-30 grams of protein per 100 grams** depending on the cut and type - **Cow milk** contains approximately **3.2-3.5 grams of protein per 100 grams** - **Sugar** is a pure carbohydrate with **0 grams of protein** *Incorrect Option: 2 → 3 → 4 → 1* - Places meat before soya bean, but soya bean has higher protein content than most meats - Incorrectly places cow milk last (milk has more protein than sugar) *Incorrect Option: 2 → 1 → 3 → 4* - Incorrectly places soya bean third, when it should be first as the highest protein source - Underestimates the exceptional protein content of soya beans *Incorrect Option: 3 → 1 → 2 → 4* - Incorrectly places cow milk before meat - Meat has significantly more protein (~20-30g) compared to milk (~3-3.5g)

Question 299: The milk of which of the following contains the least amount of calcium?

A. Cow
B. Buffalo
C. Human (Correct Answer)
D. Goat

Explanation: ***Human*** - **Human breast milk** contains the lowest concentration of calcium compared to the milk of other mammals listed. - This is physiologically appropriate as infants absorb calcium very efficiently from human milk, and higher concentrations are not necessary. *Cow* - **Cow's milk** has a significantly higher calcium content than human milk, which is suitable for the rapid growth of calf bones. - The **calcium-to-phosphorus ratio** in cow's milk is also different, which can affect absorption and metabolism in infants. *Buffalo* - **Buffalo milk** generally has an even higher calcium content than cow's milk. - It is known for its **richness in nutrients** and higher fat and protein content, contributing to its denser consistency. *Goat* - **Goat's milk** has a calcium content that is higher than human milk, though often slightly less than cow's milk. - Its calcium is absorbed relatively well, but its overall composition is still very different from human milk, particularly in terms of **protein and micronutrient balance**.

Question 300: An average-sized hen egg would provide

A. 90 Kcal
B. 70 Kcal (Correct Answer)
C. 50 Kcal
D. 110 Kcal

Explanation: ***70 Kcal*** - An average-sized hen egg (approximately 50 grams) typically provides around **70-75 kilocalories** of energy. - This energy content is primarily derived from the egg's **protein and fat** components. *90 Kcal* - This value is slightly higher than the average for a standard hen egg and might be applicable to a **larger-sized egg** or if additional ingredients are included. - The precise caloric content varies with the **size and preparation** of the egg. *50 Kcal* - This value is generally **too low** for an average-sized whole hen egg. - An egg white alone might be closer to this caloric count, as **most of the fat and calories are in the yolk**. *110 Kcal* - This caloric value is significantly **higher** than what an average hen egg provides. - Such a high value would typically be found in **very large eggs** or in egg preparations that include added fats like butter or oil.

Practice by Chapter

Macronutrients and Energy Requirements

Practice Questions

Protein Quality and Nitrogen Balance

Practice Questions

Essential Amino Acids and Proteins

Practice Questions

Essential Fatty Acids and Lipids

Practice Questions

Dietary Fiber and Complex Carbohydrates

Practice Questions

Glycemic Index and Glycemic Load

Practice Questions

Micronutrients: Vitamins and Minerals

Practice Questions

Trace Elements and Metabolism

Practice Questions

Malnutrition: Biochemical Consequences

Practice Questions

Dietary Antioxidants

Practice Questions

Functional Foods and Nutraceuticals

Practice Questions

Dietary Guidelines and Recommendations

Practice Questions

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