Why can’t insulin be given orally to diabetic patients? 

The correct answer is It will be digested in the Gastro-Intestinal (GI) tract

Concept:

• Insulin is a peptide hormone produced by the pancreas and is crucial for regulating blood sugar levels in the body. It cannot be administered orally because of its structural composition, which makes it vulnerable to enzymatic degradation in the gastrointestinal (GI) tract.
• Insulin is commonly administered through subcutaneous injections to bypass the GI tract and directly enter the bloodstream for effective action.

Explanation:

• Insulin is a protein-based molecule, and like other proteins consumed in food, it is broken down into amino acids by digestive enzymes in the stomach and intestines.
• This enzymatic breakdown prevents insulin from retaining its functional structure and biological activity, rendering it ineffective if taken orally.
• Since oral delivery is not feasible, insulin is typically given via injections (subcutaneous, intravenous, or intramuscular).
• Research is ongoing for alternative delivery methods, such as inhalable insulin, transdermal patches, and oral formulations with protective coatings or encapsulations.

Other Options:

• Human body will elicit a strong immune response:
  • The human immune system does not typically produce a strong immune response to insulin, especially if it is human recombinant insulin, which mimics the natural hormone produced in the body. Immune responses are more relevant in cases of non-human insulin or impurities in synthetic formulations, which are rare in modern medicine.
• Because of structural variation:
  • Insulin’s structure is not a limiting factor for its administration. Its molecular structure is well-suited for interaction with insulin receptors, and it performs its function effectively once in the bloodstream.
• Its bioavailability will be increased:
  • This statement is incorrect because oral administration of insulin would result in extremely low bioavailability due to enzymatic breakdown in the GI tract. Bioavailability refers to the proportion of a drug that enters circulation and can have an active effect. Oral insulin delivery significantly reduces this proportion.