NTA Nutritional Science Fundamentals 5 — Questions and Answers
Question 1: What is the key distinction between fat-soluble and water-soluble vitamins regarding storage and toxicity risk?
- Water-soluble vitamins are stored in adipose tissue and pose greater toxicity risk
- Fat-soluble vitamins accumulate in body fat and the liver, creating toxicity risk with excess intake (Correct answer)
- Both types pose equal toxicity risk because all vitamins accumulate in tissues
- Fat-soluble vitamins are excreted more rapidly than water-soluble vitamins
Correct answer: Fat-soluble vitamins accumulate in body fat and the liver, creating toxicity risk with excess intake
Fat-soluble vitamins (A, D, E, K) are stored in adipose tissue and the liver, making excessive intake potentially toxic, while water-soluble vitamins are generally excreted in urine when consumed in excess.
Question 2: Which of the following best explains why adequate stomach acid (HCl) is critical for mineral absorption?
- HCl directly transports minerals into intestinal cells
- HCl ionizes minerals and maintains the low pH needed for mineral solubility and absorption in the duodenum (Correct answer)
- HCl activates mineral-specific transport proteins in the stomach lining
- HCl prevents minerals from binding to each other, avoiding toxicity
Correct answer: HCl ionizes minerals and maintains the low pH needed for mineral solubility and absorption in the duodenum
Adequate gastric HCl ionizes minerals and creates the acidic environment necessary to keep them soluble and in forms that can be absorbed by transporters in the duodenum.
Question 3: What is the primary energy substrate used by red blood cells (erythrocytes)?
- Fatty acids
- Ketone bodies
- Glucose via anaerobic glycolysis (Correct answer)
- Glutamine
Correct answer: Glucose via anaerobic glycolysis
Red blood cells lack mitochondria and must rely entirely on anaerobic glycolysis for energy production, making glucose their obligate fuel source.
Question 4: In nutritional therapy, what does the term 'bioindividuality' primarily refer to?
- The use of biomarkers to assess nutritional status
- The recognition that each person has unique nutritional needs based on genetics, lifestyle, and health history (Correct answer)
- The biological pathways through which nutrients are metabolized
- Individual responses to specific probiotic strains
Correct answer: The recognition that each person has unique nutritional needs based on genetics, lifestyle, and health history
Bioindividuality is a core NTA principle acknowledging that no single dietary approach works for everyone, as each person's unique genetic, physiological, and environmental context shapes their nutritional requirements.
Question 5: Which of the following describes the role of the enteric nervous system (ENS) in nutrition?
- It regulates appetite hormones released from the hypothalamus
- It controls digestive motility, secretion, and gut blood flow independently of the central nervous system (Correct answer)
- It synthesizes digestive enzymes in the pancreas
- It filters toxins absorbed from the gastrointestinal tract
Correct answer: It controls digestive motility, secretion, and gut blood flow independently of the central nervous system
The ENS, sometimes called the 'second brain,' contains millions of neurons that autonomously regulate peristalsis, digestive secretions, and intestinal blood flow with minimal input from the brain.
Question 6: What is the primary reason phytic acid (phytate) in grains and legumes is considered an antinutrient?
- It inhibits digestive enzymes in the stomach
- It chelates minerals such as zinc, iron, and calcium, reducing their bioavailability (Correct answer)
- It directly damages the intestinal lining
- It increases the glycemic index of the food it is found in
Correct answer: It chelates minerals such as zinc, iron, and calcium, reducing their bioavailability
Phytic acid binds divalent minerals like zinc, iron, calcium, and magnesium in insoluble complexes that cannot be absorbed, reducing mineral bioavailability from plant foods.
Question 7: Which of the following best describes the function of the lymphatic system in fat absorption?
- It directly transports glucose from the intestine to the liver
- It carries chylomicrons from the intestinal lacteals into circulation, bypassing the portal vein (Correct answer)
- It filters fatty acids before they enter the liver
- It stores fat-soluble vitamins until they are needed by peripheral tissues
Correct answer: It carries chylomicrons from the intestinal lacteals into circulation, bypassing the portal vein
Chylomicrons assembled in enterocytes are too large to enter capillaries and instead enter intestinal lacteals (lymphatic vessels), traveling through the lymphatic system and emptying into the bloodstream at the thoracic duct.
NTA Nutritional Science Fundamentals 5
What is the key distinction between fat-soluble and water-soluble vitamins regarding storage and toxicity risk?