Why can't insulin be given orally?

[Sunny]

Hello, my father is 45 years old. He has been suffering from diabetes for past 15 years. Now he has been advised to shift on insulin daily. So he needs to take insulin injection on a regular basis. We all including my father are worried about this. He is a busy person, working as a professor. The fact that he needs to take an injection regularly makes us feel upset. Why can't be insulin taken orally? Then he does not have to go through this pain. Please comment.

[Gurdeep]

@Sunny Insulin is a hormone, normally produced in sufficient amounts by the healthy human pancreas. It's role is to facilitate the final digestion of glucose by the human body. When insulin is lacking (diabetes), glucose remains undigested in the blood. The body isn't being fed, and the high blood sugar can cause damage, the ramifications of diabetes. Insulin cannot be taken by mouth because it is digestible. Oral insulin would be obliterated in the stomach, long before it reached the bloodstream where it is needed. Once injected, it starts to work and is used up in a matter of hours. Depending on a number of factors, individuals vary insulin volume, type, and frequency, to optimize blood glucose management.