Nutrition Science Flashcards

Which macronutrient provides 9 calories per gram?

Answer: Fat

Dietary fat is the most energy-dense macronutrient, providing 9 kcal per gram compared to 4 kcal/g for protein and carbohydrate.

What is the role of secretory IgA (sIgA) in gut health?

Answer: It is the primary antibody defending mucosal surfaces from pathogens

Secretory IgA is the dominant immunoglobulin in the gut lumen and protects mucosal surfaces by neutralizing pathogens and toxins.

Which mineral deficiency is most commonly associated with goiter (enlarged thyroid gland)?

Answer: Iodine

Iodine is essential for thyroid hormone synthesis; deficiency causes the thyroid gland to enlarge in an attempt to capture more iodine from the blood.

Short-chain fatty acids (SCFAs) like butyrate, propionate, and acetate are produced when gut bacteria ferment:

Answer: Dietary fiber and resistant starch

Gut microbiota ferment indigestible dietary fiber and resistant starch to produce SCFAs, which nourish colonocytes and support gut health.

According to IIN's 'Plate' approach, which component should make up the largest portion of a healthy meal?

Answer: Non-starchy vegetables

IIN emphasizes filling half or more of the plate with non-starchy vegetables to maximize micronutrient and fiber intake.

Which form of iron is more bioavailable and is found in animal foods?

Answer: Heme iron

Heme iron, found in hemoglobin and myoglobin in meat and fish, is absorbed at a rate of 15–35%, far higher than non-heme iron from plant sources.

What is the main difference between soluble and insoluble dietary fiber?

Answer: Soluble fiber dissolves in water and forms a gel; insoluble fiber adds bulk and speeds transit

Soluble fiber (e.g., pectin, beta-glucan) dissolves in water to form a viscous gel that slows digestion and lowers cholesterol, while insoluble fiber (e.g., cellulose) adds stool bulk.