What is the primary reason biliary atresia leads to fat-soluble vitamin malabsorption?

What is the primary reason biliary atresia leads to fat-soluble vitamin malabsorption?

• A. Decreased bile acids reduce micelle formation
• B. Increased pancreatic enzymes degrade fats
• C. Increased intestinal transit time
• D. Excess bile acids cause toxicity

Answer: (A)

Bile acids are essential emulsifiers that enable the formation of micelles, which solubilize fats and fat-soluble vitamins (A, D, E, K) for absorption in the small intestine. In biliary atresia, bile flow into the gut is blocked, so fewer bile acids reach the intestinal lumen. Without enough bile acids, micelle formation is impaired, leading to poor fat digestion and fat-soluble vitamin malabsorption. The other options don’t fit as well: pancreatic enzymes can digest fat, but without bile to emulsify fats, lipase action is limited; a faster transit time isn’t the primary driver of fat-soluble vitamin malabsorption; and excess bile acids would not occur in this condition and would not cause malabsorption.

Bile acids are essential emulsifiers that enable the formation of micelles, which solubilize fats and fat-soluble vitamins (A, D, E, K) for absorption in the small intestine. In biliary atresia, bile flow into the gut is blocked, so fewer bile acids reach the intestinal lumen. Without enough bile acids, micelle formation is impaired, leading to poor fat digestion and fat-soluble vitamin malabsorption. The other options don’t fit as well: pancreatic enzymes can digest fat, but without bile to emulsify fats, lipase action is limited; a faster transit time isn’t the primary driver of fat-soluble vitamin malabsorption; and excess bile acids would not occur in this condition and would not cause malabsorption.