Nutrition knowledge popularization science protein

amino acid

The basic unit of protein.

In nutrition, according to the necessity of amino acids, it can be divided into:

Essential amino acids, conditionally essential amino acid and non-essential amino acids.

Essential amino acids: isoleucine, leucine, lysine methionine, phenylalanine, threonine, tryptophan, arginine and histidine (essential amino acids for children).

Conditionally essential amino acid: Cysteine and tyrosine can be transformed from methionine and phenylalanine respectively.

Amino acid pattern: the proportion of various essential amino acids in protein.

High-quality protein: The amino acid composition of protein is close to the essential amino acid demand pattern of human body, and it is a high-quality protein with high in-vivo utilization rate. Such as egg, milk, meat, fish and soy protein.

Protein classification

Nutritionism is divided into:

Complete protein, semi-complete protein, incomplete protein.

Complete protein: It contains all kinds of essential amino acids in sufficient quantity and proper proportion, which can not only maintain the health of adults, but also promote the growth and development of children.

Semi-complete protein: It contains all kinds of essential amino acids, but some of them are insufficient and the proportion is inappropriate. It can maintain life but cannot promote growth and development.

Incomplete protein: It contains incomplete kinds of essential amino acids, which can neither sustain life nor promote growth and development.

Complementarity of protein

Protein consumes two or more kinds of foods, and the essential amino acids contained in them complement each other, reaching a better ratio, thus improving the utilization rate of protein.

In order to give full play to the complementary role of food and protein, the following three principles should be followed when eating:

1. The biological species of food should be as far away as possible;

2. The more kinds of collocation, the better;

Eat as close as possible.

Physiological Function of protein

Constitute body tissues;

Regulating physiological functions;

Supply energy.

food source

Cereals, beans, eggs,

Milk and meat (livestock and fish).

Generally, animal protein and soybean protein should account for 30%-50% of the total dietary protein.