Excess protein can strain the liver and reduce bile production, potentially causing diarrhoea. Which organ is primarily affected?

• A. Heart
• B. Lung
• C. Kidney
• D. Liver

Answer: (D)

The liver handles amino acid metabolism and nitrogen waste removal, which makes it the organ most involved when protein intake is high. After digestion, amino acids are deaminated in the liver, producing ammonia that must be converted to urea for elimination. This places a significant workload on the liver. Bile production, essential for digesting fats, also occurs in the liver, and when the liver is strained, bile output can drop. Less bile impairs fat digestion and can lead to diarrhoea or loose stools due to fat malabsorption. The heart and lungs aren’t focused on nitrogen processing or bile production, and while the kidneys excrete urea, the described effect—reduced bile and diarrhoea from excess protein—is driven by liver function.