Nutrition and Metabolism — MCQs

Nutrition and Metabolism Indian Medical PG Practice Questions and MCQs

Question 331: What is the amount of protein (in grams) in human milk per 100 milliliters?

A. 1.1 (Correct Answer)
B. 2.2
C. 3.3
D. 4.4

Explanation: ***1.1*** - Human milk contains approximately **1.1 grams of protein per 100 milliliters**, which is appropriate for the growth and development of infants. - The protein composition of human milk is lower than that of cow's milk, but it is highly bioavailable and easily digestible due to the presence of **whey protein** and **casein**. *2.2* - This value is significantly higher than the typical protein content found in human milk. Such a high concentration could potentially strain an infant's immature kidneys. - The **protein content of cow's milk** (around 3.3-3.5 g/100ml) is much higher than human milk and is not suitable for routine infant feeding without modification. *3.3* - This protein concentration is also substantially higher than what is naturally found in human milk, possibly exceeding an infant's metabolic needs and kidney function. - This value is closer to the protein content of **unmodified cow's milk**, which is why it is often diluted or altered for infant formula. *4.4* - This protein amount is exceptionally high and not representative of natural human milk. - Excessive protein intake in infants could increase the risk of **obesity later in life** and place an undue burden on the **renal system**.

Question 332: Which of the following micronutrient deficiencies can lead to anemia?

A. Molybdenum
B. Copper (Correct Answer)
C. Fluorine
D. Selenium

Explanation: ***Copper*** - **Copper** is essential for **iron metabolism** and red blood cell formation; its deficiency can lead to **sideroblastic anemia** (often with microcytic or normocytic features) that may be accompanied by neutropenia. - Copper is required for **ceruloplasmin** function, which is necessary for iron mobilization from stores and incorporation into hemoglobin. - It also plays a role in the function of **superoxide dismutase** and **cytochrome c oxidase**, enzymes involved in antioxidant defense and energy production. *Molybdenum* - **Molybdenum** is a cofactor for several enzymes, including **xanthine oxidase** and **sulfite oxidase**, crucial for purine metabolism and detoxification. - While essential, its deficiency does not typically lead to **anemia** in humans. *Selenium* - **Selenium** is a component of selenoproteins, such as **glutathione peroxidase**, which protect cells from oxidative damage. - Deficiency is associated with conditions like **Keshan disease** (cardiomyopathy) but not primary anemia. *Fluorine* - **Fluorine** (as fluoride) is primarily known for its role in **bone and tooth mineralization**, protecting against dental caries. - It does not directly participate in **hematopoiesis** or iron metabolism, and its deficiency is not linked to anemia.

Question 333: Which macronutrient has the highest thermogenic effect?

A. Fat
B. Proteins (Correct Answer)
C. Carbohydrate
D. Alcohol

Explanation: ***Proteins*** - Proteins have the **highest thermogenic effect** (also known as the **thermic effect of food** or TEF) among macronutrients, typically ranging from **20-30%** of their caloric content. - This high TEF is due to the energy required for their **digestion**, **absorption**, and **metabolism** (e.g., deamination, protein synthesis), making them more metabolically "expensive" to process than fats or carbohydrates. *Fat* - Fat has the **lowest thermogenic effect**, accounting for approximately **0-3%** of its caloric content. - This low TEF is because fats are **easily absorbed** and stored, requiring minimal energy for their processing. *Carbohydrate* - Carbohydrates have an intermediate thermogenic effect, typically ranging from **5-10%** of their caloric content. - The energy expenditure for carbohydrate metabolism involves processes like **digestion**, **absorption**, and **glucose oxidation** or conversion to glycogen. *Alcohol* - While alcohol has a relatively high thermogenic effect (**20-25%**), it is **not classified as a macronutrient** in traditional nutritional science. - The three primary macronutrients are proteins, carbohydrates, and fats. Among these, **proteins** have the highest TEF.

Question 334: Deficiency of which element is specifically linked to the syndrome of growth failure, anemia, and hypogonadism?

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

Explanation: ***Zinc*** - **Zinc deficiency** is classically associated with **growth retardation**, **anemia**, **hypogonadism**, and impaired immune function due to its role in numerous enzymatic processes and DNA synthesis. - It plays a crucial role in **cellular growth**, development, and endocrine function, making its deficiency particularly impactful on these systems. *Calcium* - **Calcium deficiency** primarily leads to **bone demineralization** (osteoporosis or osteomalacia), tetany, and muscle cramps. - While essential for growth, it is not specifically linked to the triad of **anemia** and **hypogonadism** in the same manner as zinc. *Copper* - **Copper deficiency** can cause **anemia** (microcytic, unresponsive to iron), **neurological dysfunction** (myelopathy), and impaired immune function. - However, it is not typically associated with prominent **growth failure** and **hypogonadism** as a primary triad of symptoms. *Magnesium* - **Magnesium deficiency** can lead to **neuromuscular hyperexcitability** (tetany, spasms), cardiac arrhythmias, and fatigue. - It does not commonly present with the distinct combination of **growth failure**, **anemia**, and **hypogonadism**.

Question 335: Biological value is used for the assessment of?

A. Fat quality
B. Protein quality (Correct Answer)
C. Carbohydrate quality
D. None of the options

Explanation: ***Protein quality*** - **Biological value (BV)** is a measure of the proportion of absorbed protein from a food that is incorporated into the body's proteins. - It specifically assesses the amount and **proportions of essential amino acids** available for protein synthesis. *Fat quality* - Fat quality is typically assessed by its **fatty acid profile** (e.g., saturated, unsaturated, trans fats) and its impact on cardiovascular health. - BV is not used to evaluate the nutritional quality or absorption of lipids. *Carbohydrate quality* - Carbohydrate quality is generally determined by factors like **fiber content**, **glycemic index**, and presence of complex vs. simple sugars. - BV does not provide information about the carbohydrate composition or metabolic effects of foods. *None of the options* - This option is incorrect because biological value is a well-established method for assessing protein quality.

Question 336: What is the approximate caloric content of a large egg?

A. 50
B. 60
C. 70 (Correct Answer)
D. 80

Explanation: ***70*** - A standard large egg (approximately 50 grams) contains about **70-80 calories**. - This caloric content comes from about **6 grams of protein** and **5 grams of fat** per egg. *50* - **50 calories** is generally too low for a standard large egg. - This number might be seen in very small eggs or if only specific components (like egg whites) are considered. *60* - While closer, **60 calories** is still slightly on the lower side for an average large egg. - Caloric content can vary slightly based on egg size, but 60 is typically less than expected for a whole large egg. *80* - **80 calories** is a plausible estimate for a large egg, and some large eggs can indeed reach this amount. - However, when considering the average, **70 calories** is often cited as a more precise and common approximation.

Question 337: Which of the following protein sources has the lowest biological value?

A. Gelatin (Correct Answer)
B. Albumin
C. Cashewnut protein
D. Lactalbumin

Explanation: ***Gelatin*** - Gelatin is derived from collagen and is notably deficient in several **essential amino acids**, particularly **tryptophan**. - Its incomplete amino acid profile gives it a very **low biological value**, meaning it's poorly utilized by the body for protein synthesis. *Lactalbumin* - Lactalbumin is a **whey protein** found in milk, known for its **high biological value**. - It contains a **complete profile of essential amino acids** and is easily digestible. *Albumin* - Albumin, typically referring to **egg albumin** (egg white protein) or **serum albumin**, has an **excellent biological value**. - It is often used as a reference protein due to its well-balanced and **complete amino acid composition**. *Cashewnut protein* - While nuts like cashews provide protein, they generally have a **moderate to high biological value**, though typically not as high as animal proteins. - Cashew protein contains a good range of amino acids but might be slightly limited in one or two essential amino acids compared to a reference like egg or whey.

Question 338: In a clinical scenario, what is the approximate total body iodine content necessary for optimal thyroid function?

A. 10 mg
B. 15-20 mg (Correct Answer)
C. 30 mg
D. 50 mg

Explanation: ***Correct: 15-20 mg*** - The approximate total body iodine content in a healthy adult is **15-20 mg**, which is necessary for optimal thyroid function - Approximately **70-80% of this (10-15 mg)** is concentrated in the **thyroid gland** itself - This total body content is critical for the synthesis of **thyroid hormones (T3 and T4)**, which regulate metabolism, growth, and development - This represents the physiological requirement for maintaining normal thyroid hormone production *Incorrect: 10 mg* - While **10 mg** represents approximately the amount of iodine stored specifically in the **thyroid gland** (not total body content), the question asks for **total body iodine content** - Total body iodine includes iodine in the thyroid gland plus iodine distributed in other tissues, blood, and organs - Therefore, 10 mg underestimates the total body requirement *Incorrect: 30 mg* - **30 mg** of total body iodine content is higher than the typical physiological range (15-20 mg) found in healthy individuals - Such a high concentration is not generally required for normal synthesis of **thyroid hormones** - While not necessarily toxic, this exceeds the optimal range *Incorrect: 50 mg* - **50 mg** is significantly higher than the physiological total body iodine content required for optimal thyroid function - Excessive iodine accumulation can lead to **thyroid dysfunction**, including both the **Jod-Basedow phenomenon** (iodine-induced hyperthyroidism) and the **Wolff-Chaikoff effect** (iodine-induced hypothyroidism) - This level far exceeds normal physiological requirements

Question 339: Which of the following grains has the highest fat content?

A. Rice
B. Wheat
C. Bajra (Correct Answer)
D. Jowar

Explanation: ***Bajra*** - **Bajra** (pearl millet) generally has a higher fat content, around 5-6%, compared to other common grains. - Its unique composition includes healthy fats and essential fatty acids, contributing to its nutritional value. *Rice* - **Rice** is known for its high carbohydrate content and relatively low fat content, typically less than 1%. - It is a staple food in many cultures, primarily serving as an energy source. *Wheat* - **Wheat** contains a moderate amount of fat, usually around 1.5-2%, with the germ being the richest source of lipids. - While essential for structure, its primary nutritional contribution is carbohydrates and protein. *Jowar* - **Jowar** (sorghum) has a fat content similar to or slightly higher than wheat, typically ranging from 2-3%. - It is a drought-resistant grain, valued for its complex carbohydrates and fiber.

Question 340: Which among the following increases iron absorption?

A. Phytic acid
B. Fibre diet
C. Phosphates
D. Vitamin C (Correct Answer)

Explanation: ***Vitamin C*** - **Ascorbic acid** (Vitamin C) acts as a reducing agent, converting ferric iron (Fe3+) to ferrous iron (Fe2+), which is more soluble and readily absorbed in the duodenum. - It also forms a **chelate with iron** in the acidic environment of the stomach, preventing the formation of insoluble iron compounds. *Phytic acid* - **Phytic acid**, found in whole grains and legumes, inhibits iron absorption by binding to iron and forming insoluble complexes. - These **iron-phytate complexes** cannot be absorbed in the intestine. *Fibre diet* - A **high-fiber diet** can decrease iron absorption by reducing transit time and the bioavailability of iron. - Some components of fiber, like phytates, directly **bind to iron**, thereby inhibiting its absorption. *Phosphates* - **Phosphates** can form insoluble complexes with iron in the gut, thereby reducing its absorption. - This effect is particularly noted with **inorganic phosphate** supplements or phosphorus-rich foods.

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

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free