CDN Nutritional Science & Dietetics 4

Question 1

Which phase of digestion is stimulated by the sight and smell of food before eating begins?

Accepted Answer

Cephalic phase

Answer

The cephalic phase is the neurally mediated response to food cues (sight, smell, taste) that prepares the GI tract by stimulating saliva and gastric secretions before food arrives.

Question 2

Pellagra is caused by deficiency of which vitamin, and what is its biochemical role?

Accepted Answer

Niacin; component of NAD+ and NADP+ for redox reactions

Answer

Niacin deficiency causes pellagra (dermatitis, diarrhea, dementia, death); niacin forms NAD+ and NADP+, which are essential electron carriers in energy metabolism.

Question 3

What is the primary site of absorption for fat-soluble vitamins in the gastrointestinal tract?

Accepted Answer

Jejunum

Answer

Fat-soluble vitamins (A, D, E, K) are absorbed in the jejunum via micelle formation with bile salts, along with dietary fats.

Question 4

A dietitian is counseling an older adult on calcium intake. Which combination of factors most impairs calcium absorption?

Accepted Answer

Low gastric acid (achlorhydria) and vitamin D deficiency

Answer

Calcium solubility and absorption requires adequate gastric acid and vitamin D (which induces calcium-binding proteins in intestinal cells); both are often deficient in older adults.

Question 5

Which hormone primarily inhibits appetite by signaling satiety to the hypothalamus after a meal?

Accepted Answer

Leptin

Answer

Leptin, secreted by adipose tissue, signals the hypothalamus to suppress appetite and increase energy expenditure, reflecting long-term energy stores.

(CDN) Certified Dietician Nutritionist Practice Test

(CDN) Certified Dietician Nutritionist Practice Test

CDN Nutritional Science & Dietetics 4