Clinical Nutritionist CCN Nutritional Biochemistry and Supplementation 2 — Questions and Answers
Question 1: Which form of magnesium is most often used clinically for its muscle-relaxing and sleep-supporting properties?
- Magnesium glycinate (Correct answer)
- Magnesium sulfate
- Magnesium oxide
- Magnesium chloride
Correct answer: Magnesium glycinate
Magnesium glycinate is chelated to glycine, an inhibitory neurotransmitter, producing calming effects that support sleep and muscle relaxation with minimal laxative side effects.
Question 2: What is the mechanism by which probiotics improve intestinal barrier function in clinical nutrition?
- Upregulating tight junction protein expression (occludin, claudin) and reducing intestinal permeability (Correct answer)
- Directly synthesizing immunoglobulins in the gut lumen
- Inhibiting gastric acid secretion to prevent mucosal damage
- Competing with pathogens for receptor sites on villi only
Correct answer: Upregulating tight junction protein expression (occludin, claudin) and reducing intestinal permeability
Probiotic strains stimulate expression of tight junction proteins that seal paracellular spaces, reducing 'leaky gut,' modulating immune responses, and decreasing translocation of harmful bacteria.
Question 3: Berberine is a plant alkaloid used as a nutraceutical that exerts metabolic effects through which primary mechanism?
- Activation of AMP-activated protein kinase (AMPK), improving insulin sensitivity and lipid metabolism (Correct answer)
- Inhibition of HMG-CoA reductase similar to statins
- Blockade of intestinal lipase to reduce fat absorption
- Upregulation of hepatic LDL receptors via PCSK9 inhibition
Correct answer: Activation of AMP-activated protein kinase (AMPK), improving insulin sensitivity and lipid metabolism
Berberine activates AMPK, an energy sensor that increases glucose uptake, fatty acid oxidation, and insulin sensitivity while inhibiting gluconeogenesis and lipogenesis.
Question 4: What is the clinical significance of the ratio between omega-6 and omega-3 fatty acids in the Western diet?
- High omega-6:omega-3 ratio (15-20:1) promotes pro-inflammatory eicosanoid production, linked to chronic disease (Correct answer)
- A high omega-6:omega-3 ratio improves immune function and reduces infection risk
- The ratio is clinically irrelevant; total fat intake is more important
- Omega-6 fatty acids are always anti-inflammatory regardless of ratio
Correct answer: High omega-6:omega-3 ratio (15-20:1) promotes pro-inflammatory eicosanoid production, linked to chronic disease
The Western diet ratio of 15-20:1 favors arachidonic acid-derived pro-inflammatory eicosanoids (prostaglandins, leukotrienes); optimal health is associated with ratios closer to 4:1 or lower.
Question 5: N-acetylcysteine (NAC) is used as a supplement primarily because it is a precursor to which endogenous antioxidant?
- Glutathione (GSH) (Correct answer)
- Superoxide dismutase
- Catalase
- Coenzyme Q10
Correct answer: Glutathione (GSH)
NAC provides cysteine, the rate-limiting substrate for glutathione synthesis, replenishing this critical intracellular antioxidant and detoxification cofactor.
Question 6: Which enzyme converts linoleic acid (omega-6) and alpha-linolenic acid (omega-3) to their longer-chain derivatives?
- Delta-6 desaturase (Correct answer)
- Lipoxygenase
- Cyclooxygenase
- Phospholipase A2
Correct answer: Delta-6 desaturase
Delta-6 desaturase is the rate-limiting enzyme for elongating and desaturating ALA to EPA/DHA and linoleic acid to arachidonic acid; it is inhibited by trans fats, high glucose, and aging.
Clinical Nutritionist CCN Nutritional Biochemistry and Supplementation 2
Which form of magnesium is most often used clinically for its muscle-relaxing and sleep-supporting properties?