Amino Acids and Protein

What Are Amino Acids and How Many Are There?

Proteins are made up of amino acids. There are 21 proteinogenic amino acids. This means that only these amino acids can be used by the body to build proteins. Non-proteinogenic amino acids, however, also have important functions or serve as precursors for other amino acids.

In addition, there is a distinction between 13 essential and semi-essential amino acids. Essential amino acids must always be obtained through the diet because the body cannot produce them. Semi-essential amino acids can be produced by the body, but not always in sufficient amounts. In certain situations – such as during growth or illness — they must also be obtained through the diet.

What Are Amino Acids Good For?

As building blocks of proteins, amino acids play an important role in the body. There are: 

• Structural proteins such as collagen in connective tissue or skin 
• Muscle proteins such as actin and myosin 
• Immune proteins such as antibodies 
• Transport proteins such as hemoglobin for oxygen 
• Signaling proteins such as hormones 

How Much Protein and Amino Acids per Day?

According to the reference values for Germany, Austria, and Switzerland, the recommended daily protein intake for adults is 0.8 grams of protein per kilogram of body weight. For someone weighing 70 kilograms, this equals 56 grams of protein per day. Children, pregnant women, and older adults, however, require slightly more (0.9 to 1 gram of protein per kilogram of body weight). 

There are no official intake recommendations for individual amino acids. However, it is important to ensure an adequate intake of all essential amino acids.

Protein-Rich Foods

Foods high in protein include beef, fish, milk, dairy products, and eggs. Most protein-rich foods also contain essential amino acids.

Plant-based proteins are found in legumes such as beans, chickpeas, peas, and lentils. However, plant proteins have a lower biological value. This means they do not contain all essential amino acids and therefore cannot be fully used to build body proteins. Those following a vegan diet should therefore combine plant-based foods wisely – for example, rice with beans or chickpeas, or tofu with broccoli.