Digestion and utilization of protein

Since protein is a macromolecular substance and cannot penetrate cell membranes, human intake of protein must pass through the digestive system to decompose macromolecular proteins into amino acids of small molecules before they can be absorbed by the human body, but can amino acids be absorbed by the body? Being used by the human body to synthesize bodily tissue is another story.

After amino acids are absorbed into the blood, there are roughly three ways:

1. to be oxidized and turned into heat.

2. Enter the metabolic pathways of carbohydrates and fats.

3. Synthesize body tissues, muscles, hormones, hair nails and more.

It is important to note that various cells in the body use only the required dose of amino acids to meet protein requirements.

For example, building a house requires cement, wood, steel bars, and bricks. Without any of them, the house cannot be built.

The same is true for the human body. For humans, there are 8 essential amino acids and non-essential amino acids. We must ingest essential amino acids from the outside world. Non-essential amino acids can be synthesized by ourselves or converted from essential amino acids.

Proteins that contain all the essential amino acids are called complete proteins, and those lacking any of the essential amino acids are called incomplete proteins.

When we take in protein, our digestive organs help us break down the protein into amino acids. The body must use a complete set of amino acids. Without any amino acid, our body cannot use these amino acids.

For example, to synthesize muscle, your body needs 7 amino acids ABCDEFG as raw materials, lack of amino acid B, and the rest of the amino acids, no matter how many, your body cannot use them.

Therefore, what we most hope is that after the protein we eat is decomposed into amino acids, all of them can be absorbed and utilized to synthesize our own tissues.

The evaluation of the pros and cons of a protein depends on whether the amino acid ratio of the protein is similar to that of the human body. The more similar the amino acid ratio, the better the protein and the easier it is to be used by the body.

Since the protein in meat, egg and milk is very similar to the human body in amino acid composition, meat, egg and milk are all very high-quality protein sources.