NTP Macronutrient & Micronutrient Science 3 — Questions and Answers
Question 1: Which lipoprotein is responsible for transporting dietary triglycerides from the intestine to peripheral tissues?
- HDL
- LDL
- VLDL
- Chylomicrons (Correct answer)
Correct answer: Chylomicrons
Chylomicrons are large lipoproteins assembled in enterocytes that carry dietary triglycerides and fat-soluble vitamins through the lymphatic system to peripheral tissues.
Question 2: What is the consequence of a selenium deficiency on thyroid hormone metabolism?
- Impaired conversion of T4 to active T3 due to reduced deiodinase activity (Correct answer)
- Inability to synthesize thyroxine in the thyroid gland
- Excess iodine accumulation in the thyroid
- Overproduction of TSH from the pituitary
Correct answer: Impaired conversion of T4 to active T3 due to reduced deiodinase activity
Selenium-dependent iodothyronine deiodinases convert the prohormone T4 to the active T3; selenium deficiency reduces this conversion.
Question 3: In the NTP model, which macronutrient is considered the 'preferred' fuel for the body in an ancestral/foundational diet context?
- Glucose from refined carbohydrates
- Fat (including saturated fats from whole food sources) (Correct answer)
- Plant-based protein
- Fructose from fruit
Correct answer: Fat (including saturated fats from whole food sources)
Nutritional Therapy emphasizes that dietary fat, particularly from whole food sources, is a preferred and efficient fuel supporting metabolic health.
Question 4: Which amino acid serves as the primary gluconeogenic precursor released from skeletal muscle during prolonged fasting?
- Leucine
- Alanine (Correct answer)
- Glutamine
- Lysine
Correct answer: Alanine
Alanine is the major amino acid shuttled from muscle to the liver for gluconeogenesis via the glucose-alanine cycle.
Question 5: Vitamin C (ascorbic acid) enhances the absorption of which form of dietary iron, and by what mechanism?
- Heme iron, by increasing stomach acid
- Non-heme iron, by reducing Fe³⁺ to Fe²⁺ in the gut lumen (Correct answer)
- Both heme and non-heme iron equally, by chelation
- Non-heme iron, by increasing ferritin synthesis
Correct answer: Non-heme iron, by reducing Fe³⁺ to Fe²⁺ in the gut lumen
Vitamin C reduces ferric iron (Fe³⁺) to ferrous iron (Fe²⁺), the form absorbed by the DMT1 transporter, enhancing non-heme iron uptake.
Question 6: What is the glycemic index (GI) primarily measuring?
- The total grams of carbohydrate in a food portion
- The rate at which a food raises blood glucose relative to pure glucose (Correct answer)
- The insulin response to a meal containing fat and protein
- The fiber content of a carbohydrate food
Correct answer: The rate at which a food raises blood glucose relative to pure glucose
GI ranks foods by how quickly they raise blood glucose compared to a reference food (pure glucose = 100), based on a standard 50g carbohydrate portion.
Question 7: Which fat-soluble vitamin acts as a carboxylase cofactor essential for activating clotting factors II, VII, IX, and X?
- Vitamin A
- Vitamin D
- Vitamin E
- Vitamin K (Correct answer)
Correct answer: Vitamin K
Vitamin K is the cofactor for gamma-glutamyl carboxylase, which adds carboxyl groups to glutamate residues on clotting factors, enabling calcium binding and clot formation.
NTP Macronutrient & Micronutrient Science 3
Which lipoprotein is responsible for transporting dietary triglycerides from the intestine to peripheral tissues?