Dietary Supplements and Nutraceuticals Flashcards

Which form of magnesium is most bioavailable and least likely to cause gastrointestinal side effects at therapeutic doses?

Answer: Magnesium glycinate

Magnesium glycinate is chelated to the amino acid glycine, which significantly enhances intestinal absorption and minimizes the laxative effect associated with poorly absorbed forms like magnesium oxide.

A patient taking a statin medication asks about supplementing with CoQ10. Which statement best describes the rationale for CoQ10 supplementation in this context?

Answer: Statins inhibit the mevalonate pathway, reducing endogenous CoQ10 synthesis

Statins block HMG-CoA reductase in the mevalonate pathway, which is also required for CoQ10 (ubiquinone) synthesis, potentially contributing to statin-associated myopathy.

Which of the following best describes the upper tolerable intake level (UL) concern with preformed vitamin A supplementation in pregnant women?

Answer: Doses above 3,000 mcg RAE/day are associated with teratogenicity

Preformed vitamin A (retinol) at doses exceeding 3,000 mcg RAE per day during pregnancy is associated with fetal birth defects; provitamin A carotenoids like beta-carotene do not carry this risk.

A practitioner recommends a probiotic supplement containing Lactobacillus rhamnosus GG. This strain has the strongest evidence base for which clinical application?

Answer: Reducing the duration of antibiotic-associated diarrhea

Lactobacillus rhamnosus GG has the most robust evidence among probiotic strains for preventing and reducing the duration of antibiotic-associated diarrhea and certain infectious diarrheas.

Which factor most significantly enhances the intestinal absorption of non-heme iron from a supplement?

Answer: Co-ingesting the supplement with vitamin C (ascorbic acid)

Vitamin C reduces ferric iron (Fe³⁺) to the more soluble ferrous form (Fe²⁺) and forms a soluble chelate, both of which substantially enhance non-heme iron absorption in the intestine.

When counseling a patient about omega-3 fatty acid supplements for triglyceride reduction, which dose is generally supported by clinical evidence for a significant (>15%) triglyceride-lowering effect?

Answer: 3–4 g EPA+DHA per day

Prescription-grade omega-3 formulations and meta-analyses consistently show that 3–4 g/day of EPA+DHA are required to achieve clinically meaningful reductions (typically 20–30%) in serum triglycerides.

Which of the following best explains why methylfolate (5-MTHF) is often preferred over folic acid for individuals with MTHFR polymorphisms?

Answer: Methylfolate bypasses the conversion step catalyzed by MTHFR, delivering the active form directly

The MTHFR enzyme converts 5,10-methyleneTHF to 5-MTHF; in individuals with reduced MTHFR activity, supplementing directly with 5-MTHF bypasses this impaired conversion step, ensuring adequate active folate is available.