NTP Supplement Safety & Efficacy 2

Question 1

Which fat-soluble vitamin poses the greatest toxicity risk when taken in excessive supplemental doses over time?

Accepted Answer

Vitamin A

Answer

Vitamin A (retinol) accumulates in the liver and causes toxicity at doses above 10,000 IU/day long-term, leading to liver damage, bone loss, and teratogenicity.

Question 2

A client taking warfarin asks about fish oil supplementation. What is the primary safety concern?

Accepted Answer

Fish oil has additive anticoagulant effects and may increase bleeding risk

Answer

Fish oil has mild antiplatelet and anticoagulant properties that can potentiate warfarin's blood-thinning effects, increasing bleeding risk.

Question 3

What is the Tolerable Upper Intake Level (UL) for zinc in adults, above which adverse effects become likely?

Accepted Answer

40 mg/day

Answer

The UL for zinc is 40 mg/day for adults; exceeding this chronically can cause copper deficiency, immune suppression, and nausea.

Question 4

Which supplement interaction is most clinically significant for a client taking thyroid hormone medication (levothyroxine)?

Accepted Answer

Calcium and iron supplements taken simultaneously impair levothyroxine absorption

Answer

Calcium and iron bind levothyroxine in the GI tract, reducing absorption by up to 40%; they should be taken at least 4 hours apart.

Question 5

St. John's Wort is contraindicated with many medications primarily because it:

Accepted Answer

Strongly induces CYP3A4 and P-glycoprotein, reducing drug efficacy

Answer

St. John's Wort is a potent CYP3A4 inducer that accelerates metabolism of numerous drugs including birth control, antiretrovirals, and cyclosporine, reducing their effectiveness.

(NTP) Nutritional Therapy Practitioner Practice Test

(NTP) Nutritional Therapy Practitioner Practice Test

NTP Supplement Safety & Efficacy 2