What is a known effect of excessive ascorbic acid intake?

• A. Megadoses can cause rebound effects including cramps, diarrhea, and nausea.
• B. Vitamin C toxicity has no known adverse effects.
• C. Megadoses can cause rebound effects including cramps, diarrhea, nausea, kidney stones, and gout.
• D. Chronic constipation is the primary concern.

Answer: (C)

Excessive intake of vitamin C can cause GI upset and kidney stone formation. When you push far beyond the amount the gut can absorb, unabsorbed vitamin C pulls water into the intestine, leading to cramps, diarrhea, and nausea. The surplus vitamin C is also metabolized to oxalate, increasing urinary oxalate and raising the risk of calcium oxalate stones. In some discussions, megadoses are also linked to other metabolic disturbances that may affect those prone to gout, but the strongest, well-established adverse effects are the GI symptoms plus kidney stones. That’s why this option best reflects the known risks of very high vitamin C intake.