Macronutrient & Micronutrient Science Flashcards

Which lipoprotein is responsible for transporting dietary triglycerides from the intestine to peripheral tissues?

Answer: Chylomicrons

Chylomicrons are large lipoproteins assembled in enterocytes that carry dietary triglycerides and fat-soluble vitamins through the lymphatic system to peripheral tissues.

What is the consequence of a selenium deficiency on thyroid hormone metabolism?

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.

In the NTP model, which macronutrient is considered the 'preferred' fuel for the body in an ancestral/foundational diet context?

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.

Which amino acid serves as the primary gluconeogenic precursor released from skeletal muscle during prolonged fasting?

Answer: Alanine

Alanine is the major amino acid shuttled from muscle to the liver for gluconeogenesis via the glucose-alanine cycle.

Vitamin C (ascorbic acid) enhances the absorption of which form of dietary iron, and by what mechanism?

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.

What is the glycemic index (GI) primarily measuring?

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.

Which fat-soluble vitamin acts as a carboxylase cofactor essential for activating clotting factors II, VII, IX, and X?

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.