Why is thiamin deficiency seen in patients with heart failure?

• A. Dietary deficiency only
• B. Furosemide and digoxin may decrease thiamin uptake by cardiac cells in patients with heart failure
• C. Increased excretion due to diuretics with kidney failure
• D. Thiamin irrelevant to heart failure

Answer: (B)

Thiamine is essential for energy production in the heart, so deficiency can worsen heart failure. In many patients with heart failure, loop diuretics like furosemide are used to manage fluid overload. These diuretics increase urinary loss of thiamine, which can deplete body stores. There is also evidence that furosemide, and possibly interactions with digoxin, can reduce thiamine uptake by cardiac cells, decreasing intracellular thiamine where it’s needed for crucial metabolic enzymes. This combination helps explain why thiamine deficiency can occur even when dietary intake is adequate. It’s not simply a dietary issue, nor is it solely about kidney excretion with kidney failure, and thiamine status is still relevant to heart function.