How are amino acids synthesized in the human body?

Much more, both sugars and lipids can be converted into proteins, but very little is converted into lipids. 1。Self-protein breakdown, 2.

Some intermediates [e.g., pyruvate] are converted into amino acids by transamination,3. Digestion and absorption of protein in food...

The three nutrients can be converted into each other.

There are a total of 20 kinds of amino acids, of which 12 can be synthesized by the human body, which are called non-essential amino acids.

The other 8 kinds cannot be synthesized by the human body, which are called essential amino acids.

Supplement: (essential amino acid--- methionine.

Valine, lysine.

Isoleucine, phenylalanine.

Leucine, tryptophan masking, threonine).Homophonic macro with orange memory: A brings a two-color book.

If you memorize these 8 essential amino acids, you don't have to be afraid of this part of the topic. I hope it helps you.

Theoretically, there are an infinite number of amino acids, as long as there is an amino group and a carboxyl group attached to a carbon group, and there is no effective peptide bond. However, only 20 amino acids are used in the protein formed by the deficiency of raw materials. Only these 20 natural amino acids can strictly adhere to the general formula of the structure, and they are:

1 Tryptophan 2 Lysine 3 Phenylalanine 4 Methionine 5 Threonine 6 Valine 7 Leucine 8 Isoleucine 9 Cysteine 10 Serine 11 Glycine 12 Tyrosine 13 Aspartic Acid 14 Asparagine 15 Glutamic Acid 16 Glutamine 17Alanine 18, Arginine 19, Histidine 20The first 8 types of proline are called essential amino acids, which cannot be synthesized in the human body and need to be obtained from food.

The amount of arginine and histidine synthesized by the human body generally does not meet its own requirements, and it is still necessary to dig into Bi Juqin to further obtain from food, these two amino acids we call semi-essential amino acids. The remaining 10 are non-essential amino acids that can be synthesized on their own.

There are a total of 20 kinds of amino acids, and more than 100,000 proteins in the human body are formed by these 20 kinds of amino acids through different combinations. Therefore, amino acids are the "bricks" of life, and the body is the "building of life" built by using these raw materials. Of these, 9 cannot be crafted on their own, and the other 11 can be crafted by the other 9.

And leucine, isoleucine, and cathonine, known as the branched-chain amino acid BCAA, are the most abundant in muscles.

Proteins have 5 main functions:

1. Raw materials for human body structure.

2. Catalyst for biochemical reactions.

3. Hormones. 4. Fight against disease.

5. Provide heat.

According to the quality of the protein, it can be divided into:

1. Complete protein: fish, meat, eggs, milk beans; Fish (fish and shrimp), meat (poultry), eggs (various eggs), milk (various milks), beans (soybean products).

2. Incomplete protein: lack of certain essential amino acids, such as the lack of lysine in rice and the lack of tryptophan in corn.

3. Complementary protein: Other legumes other than soybeans are usually deficient in methionine, so the combination of rice + beans (red bean rice) is very good.

Protein can be divided into amino acid correction scores according to digestibility:

1. The highest digestibility (PDCAAS:

Animal protein (egg, milk and meat), soy protein, whey protein powder.

2. Medium digestibility (PDCAAS>

Other legumes (72% 84%), nuts such as peanuts, root vegetables.

3. Low digestibility (PDCAAs<

Flour, rice, corn and other plant foods.

In general, eggs, milk and animal foods have higher protein absorption and utilization, and plant foods are lower than animal foods except soy protein and soybean protein. Some collagen drinks on the market are actually very low in PDCAAS, only, that is to say, the absorption and utilization rate of these "supplements" is very low, and they cannot play the role of protein supplementation, let alone collagen supplementation.

How much protein should I eat per day?

General population: The "Dietary Nutrition Guidelines for Chinese Residents" recommends 65g for men and 55g for women.

The American Dietary Nutrition Guidelines Office Population Doubles Body Weight, 60kg*, Chinese Dietary Guidelines recommend that protein accounts for 15 35% of the three major nutrients in energy, according to the daily calorie intake of 2000kcal, the daily protein should be 300 700kcal, that is, 75g 175g

**Author: "Nutrition Research", weight * times.

Exerciser: American College of Sports Medicine, weight*

Athlete: International Sports Nutrition Association, weight*

The main benefits of eating more protein are:

1. Increase satiety.

2. Suppress hunger.

3. Increase the thermal effect of food.

4. Less muscle breakdown.