Amino Acids Deficient in Collagen

Amino acids deficient in collagen are:

Correct Answer: Cysteine, Tryptophan

Collagen is deficient in Cysteine and Tryptophan — both of which are essential amino acids. This makes collagen an incomplete protein nutritionally.

Nutritional Significance

• Diets high in collagen-rich cuts (tendons, skin, cartilage) are nutritionally inadequate if used as the sole protein source
• Tryptophan is the precursor to serotonin and niacin; its deficiency causes Pellagra
• Cysteine is involved in antioxidant defence (part of glutathione)

Blood Meal Contrast

Blood meal is a rich source of Lysine — making it a valuable supplement for diets deficient in lysine (e.g., maize-based diets). Compare this with collagen which lacks cysteine and tryptophan.