Question at position 14 High doses of what vitamin can reduce cholesterol and triglyceride levels in the blood?NiacinBiotinThiamineRiboflavinPantothenic acid单项选择题
A
Niacin
B
Biotin
C
Thiamine
D
Riboflavin
E
Pantothenic acid

Question

Question at position 14 High doses of what vitamin can reduce cholesterol and triglyceride levels in the blood?NiacinBiotinThiamineRiboflavinPantothenic acid

BlackTom AI · Accepted Answer

Niacin (vitamin B3) at pharmacologic (high) doses is the vitamin that lowers cholesterol and triglyceride levels.

1. Relevant knowledge points and concepts
- Niacin = vitamin B3; at high doses it is used as a lipid-modifying agent.  
- Mechanisms: niacin inhibits adipose tissue hormone-sensitive lipase (reducing free fatty acid release), decreases hepatic triglyceride synthesis and very-low-density lipoprotein (VLDL) production, and reduces HDL catabolism (raising HDL).  
- Clinical effects: lowers VLDL and LDL, reduces triglycerides, and raises HDL. Adverse effects include flushing (prostaglandin-mediated), hepatotoxicity, hyperglycemia, and hyperuricemia.

2. Step-by-step reasoning process
- Identify vitamins listed: Niacin (B3), Biotin (B7), Thiamine (B1), Riboflavin (B2), Pantothenic acid (B5).  
- Recall which B vitamin is used pharmacologically for dyslipidemia: clinical practice and pharmacology texts list niacin as the agent that, when given in gram doses, reduces triglycerides and LDL and raises HDL.  
- Tie mechanism to lipid changes: inhibition of hormone-sensitive lipase → fewer free fatty acids delivered to liver → decreased hepatic triglyceride synthesis → decreased VLDL secretion → lower plasma triglycerides and LDL. Niacin also slows ApoA-I catabolism → increased HDL.

3. Intermediate steps/calculations
- No numerical calculation is required; logical biochemical steps: Niacin → ↓ adipose lipolysis → ↓ FFA to liver → ↓ hepatic TG synthesis → ↓ VLDL secretion → ↓ plasma TG and LDL and ↑ HDL.

4. Why the correct answer is correct
- Niacin’s direct effects on adipose lipolysis and hepatic TG/VLDL production produce the observed reductions in cholesterol and triglycerides. This pharmacologic use of niacin is well-established.

5. Why other options are incorrect
- Biotin (B7): cofactor for carboxylases (gluconeogenesis, fatty acid synthesis) but not used to lower cholesterol.  
- Thiamine (B1): cofactor for decarboxylation reactions; used for beriberi/Wernicke-Korsakoff, not lipid lowering.  
- Riboflavin (B2): component of FAD/FMN used in redox reactions; not a lipid-lowering therapy.  
- Pantothenic acid (B5): component of coenzyme A; no role as a therapeutic lipid-lowering agent.

6. Conclusion / confirmation
Niacin is the correct answer. This explanation confirms the provided answer: Niacin.

Question at position 14 High doses of what vitamin can reduce cholesterol and triglyceride levels in the blood?NiacinBiotinThiamineRiboflavinPantothenic acid单项选择题

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