Nutrition and Metabolism Practice Questions

Q: Which of the following is not a dietary fiber?

Starch. ***Starch*** - **Starch** is a **complex carbohydrate** that serves as a major energy source for humans and can be digested into glucose. - Unlike dietary fiber, starch is broken down by enzymes (like **amylase**) in the digestive tract, absorbed, and used for energy. *Cellulose* - **Cellulose** is a **polysaccharide** found in the cell walls of plants and is a major component of dietary fiber. - Humans lack the enzymes to digest cellulose, so it passes through the digestive system largely intact, adding **bulk to stool**. *Pectin* - **Pectin** is a **soluble dietary fiber** found in fruits, particularly apples and citrus. - It forms a gel-like substance when mixed with water and is known for its ability to lower cholesterol and regulate blood sugar. *Inulin* - **Inulin** is a **soluble dietary fiber** and a type of fructan, found in many plants like chicory root, onions, and garlic. - It acts as a **prebiotic**, promoting the growth of beneficial gut bacteria in the colon.

Q: Which nutrient is essential for collagen synthesis?

Vitamin C. ***Vitamin C*** - **Vitamin C (ascorbic acid)** is absolutely essential as a cofactor for **prolyl hydroxylase and lysyl hydroxylase** enzymes - These enzymes hydroxylate proline and lysine residues in procollagen, which is critical for **stable collagen triple helix formation** - Deficiency causes **scurvy** with defective collagen leading to bleeding gums, poor wound healing, and perifollicular hemorrhages - **Copper** (as a cofactor for lysyl oxidase) is also important for collagen cross-linking but Vitamin C is the primary essential nutrient for synthesis *Vitamin D* - Primarily involved in **calcium and phosphate metabolism** and bone mineralization - Deficiency leads to **rickets** (children) and **osteomalacia** (adults), not defective collagen - No direct role in collagen synthesis pathways *Folic acid* - Essential for **DNA synthesis, cell division**, and red blood cell formation - Plays no direct role in the **enzymatic mechanisms of collagen formation** - Deficiency causes megaloblastic anemia *Vitamin A* - Important for **vision, immune function**, epithelial integrity, and cell differentiation - While it influences tissue health, it is not a direct cofactor for **collagen synthesis enzymes**

Q: Which of the following minerals is needed for fertility?

Zinc. ***Zinc*** - Zinc is crucial for **reproductive health** in both men and women, impacting **testosterone synthesis**, **spermatogenesis**, egg quality, and **hormone regulation**. - Essential for **gonadal development** and function in both sexes. - Deficiency leads to **hypogonadism**, reduced fertility, impaired sperm production, and increased risk of **miscarriage**. - Most commonly deficient mineral affecting fertility globally. *Selenium* - Selenium is also **essential for male fertility**, being a critical component of **glutathione peroxidase** in sperm mitochondria. - Required for **sperm motility**, morphology, and structural integrity of the sperm midpiece. - Deficiency can cause male infertility due to impaired sperm function. - However, zinc deficiency is more prevalent and has broader effects across both male and female reproductive systems. *Iron* - Iron is vital for **red blood cell formation** and preventing **anemia**. - Severe iron deficiency anemia can **impair ovulation** and indirectly affect fertility in women. - Not directly involved in reproductive processes at the cellular level like zinc. *Copper* - Essential for various enzymatic functions but not primarily associated with fertility. - **Excessive copper** can negatively impact fertility and cause hormonal imbalances. - Deficiency is rare and not a primary cause of infertility.

Q: A 70 kg farmer is consuming 56 grams of protein, 275 grams of carbohydrates, and 60 grams of lipids. How does his caloric intake compare to the estimated daily needs for a moderately active male?

Less than the recommended intake. ***Less than the recommended intake*** - The farmer's total caloric intake is approximately 1864 kcal (Protein: 56g x 4 kcal/g = 224 kcal; Carbs: 275g x 4 kcal/g = 1100 kcal; Lipids: 60g x 9 kcal/g = 540 kcal), which is **lower than the estimated needs** for a moderately active male. - A moderately active male typically requires about **2400-2800 kcal/day** depending on age and specific activity levels. *More than the recommended intake* - His calculated intake of 1864 kcal is on the **lower end** and does not exceed the general recommendations for moderately active adult males. - This option would be correct if the calculated intake was significantly higher than the average daily caloric requirements. *Adequate for his needs* - While 1864 kcal might be adequate for a very sedentary lifestyle, a farmer (implied to be **moderately active**) would generally require a **higher caloric intake** to meet energy demands and maintain body weight. - A caloric intake closer to 2400-2800 kcal/day would be considered more appropriate for a moderately active individual. *Cannot be determined* - The caloric content of macronutrients is standard (4 kcal/g for protein and carbohydrates, 9 kcal/g for lipids), allowing for a **direct calculation** of total caloric intake. - While exact individual needs can vary, general dietary guidelines provide a sufficient basis to assess if this intake is likely low, adequate, or high for a moderately active individual.

Q: What is the recommended daily protein intake for a healthy adult male?

1 gm/kg/day. ***1 gm/kg/day*** - The recommended daily protein intake for healthy adults is generally around **0.8 to 1.0 gram per kilogram of body weight** to maintain nitrogen balance and prevent deficiency. - This intake supports normal bodily functions, tissue repair, and muscle maintenance in non-athletic individuals. *0.5 gm/kg/day* - This amount is generally considered **below the optimal daily protein intake** for most healthy adults and may be insufficient to maintain proper nitrogen balance. - While it may prevent overt deficiency in some sedentary individuals, it does not support optimal muscle protein synthesis or recovery for active or moderately active adults. *1.5 gm/kg/day* - This level of protein intake is often recommended for individuals who are **highly active, engaged in resistance training**, or aiming for muscle gain. - While not harmful for most healthy individuals, it generally **exceeds the basic requirements** for a typical healthy adult male not involved in intense physical activity. *2 gm/kg/day* - This is a very high protein intake, often utilized by **competitive athletes, bodybuilders**, or individuals on specific weight loss programs. - While generally safe for healthy kidneys, it is **significantly higher than the recommended daily allowance** for the average healthy adult and not necessary for general health maintenance.

Q: Which of the following factors in diet increases iron absorption?

Vitamin C. ***Vitamin C*** - **Vitamin C** (ascorbic acid) enhances **non-heme iron absorption** by reducing ferric iron (Fe3+) to ferrous iron (Fe2+), which is more soluble and readily absorbed in the gut. - It also counteracts the inhibitory effects of certain dietary components like **phytates and tannins** on iron absorption. *Iron-fortified foods* - While iron-fortified foods *provide* iron, they don't inherently increase the *efficiency* of absorption of all forms of iron present in the meal. - The absorption of iron from these foods still depends on the **form of iron used** for fortification and the presence of **absorption enhancers** or inhibitors. *Vitamin A* - **Vitamin A** plays a role in iron metabolism by influencing red blood cell development and mobilization of iron from stores, but it does **not directly enhance iron absorption** from the gut. - Deficiency in Vitamin A can *exacerbate* iron deficiency anemia, but its supplementation doesn't primarily serve to increase absorption. *Fibre diet* - A **high-fibre diet** can *decrease* iron absorption because certain components of fibre, particularly **phytates** (found in whole grains and legumes), bind to iron and hinder its uptake. - While fibre is important for digestive health, it is generally considered an **inhibitor** of iron absorption, especially of non-heme iron.

Q: All of the following are examples of Dietary fibre except for which of the following?

Starch. ***Correct: Starch*** - **Starch** is a **polysaccharide** that serves as a **storage carbohydrate** in plants and is readily digestible by human enzymes, breaking down into glucose. - While it's a carbohydrate found in plant foods, it does not fit the definition of dietary fibre which is generally resistant to human digestive enzymes. *Incorrect: Pectin* - **Pectin** is a type of **soluble dietary fibre** found in fruits, particularly apples and citrus. - It forms a gel in water, contributing to satiety and helping to **lower cholesterol** and **regulate blood sugar**. *Incorrect: Lignin* - **Lignin** is a **non-carbohydrate dietary fibre** that provides structural support in plants. - It is an **insoluble fibre** and is resistant to breakdown by digestive enzymes, aiding in bulk formation in stool. *Incorrect: Cellulose* - **Cellulose** is a major component of **plant cell walls** and is a type of **insoluble dietary fibre**. - It adds bulk to stool, promoting regularity and preventing constipation.

Q: Protein quality assessment is best done by?

NPU. ***NPU*** - **Net Protein Utilization (NPU)** is considered the best method for assessing protein quality because it measures the percentage of ingested protein that is actually retained and utilized by the body. - It accounts for both the **digestibility** of the protein and the **biological value** of the absorbed amino acids, providing a comprehensive assessment. *Biological value* - **Biological Value (BV)** measures the proportion of absorbed protein from food that becomes incorporated into proteins in the organism's body. - While important, BV does not account for the **digestibility** of the protein, meaning some protein may not be absorbed even if its amino acid profile is excellent. *Digestibility coefficient* - The **digestibility coefficient** measures the proportion of food protein that is absorbed from the gastrointestinal tract. - It only reflects the extent of **absorption** and does not provide information about how efficiently the absorbed amino acids are utilized once inside the body for protein synthesis. *Amino acid score* - The **amino acid score** compares the amino acid profile of a test protein with the amino acid requirements of humans. - This score identifies the **limiting amino acid** but does not factor in the protein's digestibility or how effectively the absorbed amino acids are used by the body.

Q: Which food item contains the highest protein content among the following options?

Soyabean. ***Soyabean*** - **Soybeans** are considered a complete protein, containing all **nine essential amino acids** required for human health. - They typically contain about **36-40 grams of protein per 100 grams** (dried/raw), making them one of the richest plant-based protein sources. - This is **significantly higher** than any of the other options listed. *Egg* - A **large egg** contains approximately **6 grams of high-quality protein**, including all essential amino acids. - Per 100 grams, eggs provide about **12-13 grams of protein** - excellent quality but much lower quantity than soybeans. *Rice* - **Rice**, particularly white rice, is primarily a source of **carbohydrates** and contains relatively low protein content. - Raw white rice provides about **7 grams of protein per 100 grams** (uncooked), making it the lowest protein source among these options. *Wheat* - **Wheat** is a grain rich in carbohydrates and also contains a moderate amount of protein, primarily **gluten**. - Whole wheat grain contains approximately **13-14 grams of protein per 100 grams**, which is comparable to eggs but significantly less than soybeans.

Question 1

Which of the following is not a dietary fiber?

Accepted Answer

Starch

Answer

Cellulose

Answer

Pectin

Answer

Inulin

Question 2

Which nutrient is essential for collagen synthesis?

Accepted Answer

Vitamin C

Answer

Vitamin D

Answer

Folic acid

Answer

Vitamin A

Question 3

Which of the following minerals is needed for fertility?

Accepted Answer

Zinc

Answer

Copper

Answer

Iron

Answer

Selenium

Question 4

A 70 kg farmer is consuming 56 grams of protein, 275 grams of carbohydrates, and 60 grams of lipids. How does his caloric intake compare to the estimated daily needs for a moderately active male?

Accepted Answer

Less than the recommended intake

Answer

More than the recommended intake

Answer

Adequate for his needs

Answer

Cannot be determined

Question 5

What is the recommended daily protein intake for a healthy adult male?

Accepted Answer

1 gm/kg/day

Answer

0.5 gm/kg/day

Answer

1.5 gm/kg/day

Answer

2 gm/kg/day

Question 6

Which of the following factors in diet increases iron absorption?

Accepted Answer

Vitamin C

Answer

Iron-fortified foods

Answer

Vitamin A

Answer

Fibre diet

Question 7

Which of the following statements about phosphorus is true?

Accepted Answer

Comprises about 1% of the total body weight

Answer

Parathormone acts on NaPiIIc receptors

Answer

Most of it (85%) is found in the bones

Answer

Dietary phosphorus deficiency is common in healthy individuals

Question 8

All of the following are examples of Dietary fibre except for which of the following?

Accepted Answer

Starch

Answer

Pectin

Answer

Lignin

Answer

Cellulose

Question 9

Protein quality assessment is best done by?

Accepted Answer

NPU

Answer

Biological value

Answer

Amino acid score

Answer

Digestibility coefficient

Question 10

Which food item contains the highest protein content among the following options?

Accepted Answer

Soyabean

Answer

Egg

Answer

Rice

Answer

Wheat

Nutrition and Metabolism — MCQs

Nutrition and Metabolism — MCQs

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