Complete animal protein: what it is and why beef is an important source

Complete animal protein is protein that provides all nine essential amino acids: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. The body cannot produce them in sufficient quantities and therefore needs to obtain them through food.

During digestion, proteins are broken down into amino acids. Once absorbed, these compounds can be used to build and renew the proteins found in muscles, organs, skin and other tissues.

Meat, fish, eggs, milk and dairy products are among the main animal sources of complete proteins. Beef, specifically, contains all nine essential amino acids in adequate proportions, as explained in the My Minerva article about the differences between plant- and animal-based proteins.

Browse the content:

• Why is complete animal protein important for health?
• What does science say about complete animal protein?
• Who benefits from consuming complete animal protein?
• How can complete animal protein be included in the diet?
• Myths and facts about complete animal protein
• All animal-based protein is complete
• Beef provides all the essential amino acids
• Only animal-based foods provide essential amino acids
• Plant proteins must be combined in the same meal
• Consuming enough protein helps maintain muscle
• Consuming more protein always builds more muscle

Why is complete animal protein important for health?

The amino acids supplied by proteins contribute to the formation, maintenance and repair of tissues. They are also used to produce enzymes, hormones, neurotransmitters and components related to immune system function.

Among these amino acids is leucine, which participates in signaling involved in muscle protein synthesis. However, building and preserving muscle depends on the combined availability of essential amino acids, as well as sufficient energy, physical activity and other nutrients.

Therefore, adequate consumption of complete animal protein contributes to growth, tissue recovery and the maintenance of muscle mass. My Minerva explores this relationship in the article Protein: What Do I Need You For? The Relationship Between Protein Intake, Strength and Muscle Mass Throughout Aging.

What does science say about complete animal protein?

A food should not be assessed solely by the amount of protein it provides, but also by the quality of that protein. Therefore, its essential amino acid profile and the bioavailability of these nutrients should be considered—that is, how much of these compounds can actually be absorbed and used.

The report Dietary Protein Quality Evaluation in Human Nutrition, by the FAO, recommends the Digestible Indispensable Amino Acid Score (DIAAS) method for assessing protein quality. This system analyzes the digestibility of each essential amino acid in the small intestine and compares its availability with human requirements.

The report Protein and Amino Acid Requirements in Human Nutrition, prepared by the WHO, FAO and United Nations University, also emphasizes that diet quality depends on the sufficient availability of essential amino acids to meet the body’s needs.

Beef has a complete amino acid profile and good digestibility. These characteristics explain why it is considered a high-quality protein source, a topic addressed by My Minerva in its article on the quality and digestibility of red-meat protein.

Who benefits from consuming complete animal protein?

Protein is necessary at every stage of life because the body continuously renews its cells and tissues. However, some groups need to pay closer attention to the quantity and quality of protein sources in their diets.

Children and adolescents use amino acids during growth, while pregnant and breastfeeding women go through periods of increased nutritional demand. Physically active people and athletes also need protein for tissue recovery after exercise.

Among older adults, adequate intake contributes to preserving muscle mass, strength and functionality. People recovering from illnesses, injuries or surgery may also have specific needs that should be assessed individually.

The importance of protein and other nutrients during these stages is detailed in the My Minerva content about the role of meat in the diets of women, pregnant women, children and older adults.

How can complete animal protein be included in the diet?

Beef can be part of meals that also include rice, beans, vegetables, leafy greens and other foods. In this way, the plate provides protein, carbohydrates, fiber, vitamins and minerals.

Different beef cuts provide complete proteins, although they vary in fat content. It is therefore possible to alternate cuts and cooking methods, prioritizing boiled, roasted, stewed or grilled recipes according to individual needs.

Fish, poultry, eggs, milk and dairy products also provide complete proteins. Plant-based foods contribute to protein intake and can meet amino acid needs when they are part of a varied and well-planned diet.

The appropriate amount of protein varies according to age, weight, physical activity and health status. Therefore, there is no single serving size recommended for everyone.

Myths and facts about complete animal protein

All animal-based protein is complete

Myth. Most animal-based proteins provide all nine essential amino acids in adequate amounts. However, there are exceptions, such as gelatin, which is obtained from collagen found in animal tissues and does not have a complete profile because it does not provide all essential amino acids in adequate proportions—especially because it contains little or no tryptophan. 

Beef provides all the essential amino acids

Fact. Beef contains the nine amino acids that the body needs to obtain from food. This composition is among the factors that determine its high protein quality.

Only animal-based foods provide essential amino acids

Myth. Plant-based foods also provide essential amino acids, although their amounts and proportions may vary. A diverse and well-planned plant-based diet can provide all these components throughout the day.

Plant proteins must be combined in the same meal

Myth. It is not mandatory to bring all complementary sources together in the same dish. However, the variety of foods consumed throughout the day can provide the necessary amino acids.

Consuming enough protein helps maintain muscle

Fact. Adequate intake provides amino acids used to maintain and renew muscle tissue. However, preserving muscle mass also depends on physical activity, sufficient energy intake and individual conditions.

Consuming more protein always builds more muscle

Myth. Muscle development does not depend solely on the amount of protein. Strength training, rest, energy intake and individual characteristics also influence this process.