How Much Protein Do I Need? Where Can I Find It?

A Few Words About Proteins

Proteins are one of the three basic macronutrients in our diet, along with carbohydrates and lipids.

Their name comes from the word “proteus” which means “first” and reflects the great importance they have for the functioning of our body. Adequate daily protein intake is particularly important as proteins are involved in many of the functions of the human body.

The building blocks of proteins are amino acids, which join together to form proteins. Amino acids, in turn, are classified into:

• Essential amino acids. These are amino acids that the human body cannot synthesize. Thus, the only way to obtain them is through diet.

• Non-essential amino acids. These are amino acids that are produced-synthesized in sufficient quantities by the human body and their intake through diet is not considered necessary.

• Semi-essential amino acids. These amino acids are closer to the category of non-essential amino acids. They are usually synthesized in sufficient quantities by the human body. However, in specific cases such as certain pathological conditions, the body is completely unable to synthesize them, or does not synthesize them in the quantity and at the rate required.

What Are the Functions of Proteins?

The functions of proteins in our body are many and varied.

Some of these include:

They Function as a Structural Component

Proteins “build” cells and tissues.

For example, myosin and actin are the proteins that form the basic structural components of our muscles.

Also, collagen, which is the most abundant protein in the human body, is a key component of skin, bones, tendons, and more.

They Function as Catalysts for Chemical Reactions

The enzymes that act as catalysts for the thousands of chemical reactions taking place in our body are protein molecules.

Essentially, enzymes catalyze reactions that could occur even without their presence.

However, with the presence of enzymes, the speed of reactions increases up to even 100 million times.

This practically means that reactions that take place, in the presence of enzymes, within one minute, would take 32 months to occur without them.

They Function as Transporters

For example, hemoglobin is a transport protein found in red blood cells.

It is characterized as a transporter because it is essential for the transport of oxygen from the lungs to various tissues in our body.

Without it, the body loses the ability to transport oxygen, resulting in the function of all systems in our body being affected.

They Function as Antibodies

Proteins enhance our immune system.

Consider that antibodies are proteins produced by our immune system and destroy pathogenic microorganisms.

They Function as Hormones

Proteins play an important role in cell function as they also act as hormones.

For example, insulin which regulates blood sugar levels is a protein.

So, without a doubt, for the proper functioning of the body, we need adequate protein intake.

How Much Protein Should We Consume Through Our Diet?

The recommended daily protein intake for a healthy adult is set at:¹

“0.83 g of protein/kilogram (kg) of body weight/day”

This practically means that if you weigh 75 kg, you should consume (75*0.83)= 62 grams of protein daily.

This amount is sufficient to avoid inadequate protein intake.

There are also some population groups that have increased protein needs, such as pregnant and lactating women, some patients (e.g., those with injuries), and athletes.

Specifically, according to the European Food Safety Authority, the following applies for pregnant and lactating women:

• Pregnant women in the 1^st trimester of pregnancy: + 1 g/day

• Pregnant women in the 2^nd trimester of pregnancy: + 9 g/day

• Pregnant women in the 3^rd trimester of pregnancy: + 28 g/day

• Lactating women: + 19 g/day

What Are the Protein Needs of the Elderly?

Although until now the recommended protein intake for people over 65 years old is 0.83 g/kg body weight/day, the same as for younger individuals, in recent years, many researchers and scientists have expressed their objections to this amount, suggesting its replacement with at least 1 gram daily for the prevention of sarcopenia.

Age-related muscle loss, called sarcopenia, is a normal phenomenon that occurs with the passage of years.

In fact, the decrease in muscle mass can start as early as 30 years old, reaching up to 3-5% per decade, and results in less strength and mobility, and consequently an increased risk of falls and fractures.

Although sarcopenia is a normal consequence of the aging process, it doesn’t mean it can’t be limited.

Protein plays a crucial role in building and maintaining muscle mass.

For this reason, many recommend increasing daily protein intake for the elderly to prevent the onset of sarcopenia, a condition that significantly degrades the quality of life of individuals.

What happens in the case of those who exercise?

It is undeniable that exercisers/athletes have higher protein requirements compared to individuals who lead a sedentary lifestyle.

This happens because during exercise, due to mechanical stress, muscle protein breakdown occurs.

Consequently, when someone exercises, a greater supply of protein is required both for muscle tissue repair and for stimulating muscle hypertrophy.

The recommendations of the International Society of Sports Nutrition (ISSN) state that for the maintenance and increase of muscle mass, a daily protein intake of 1.4-2 g/kg body weight/day is sufficient for most athletes/exercisers.²

The exact requirements depend on the characteristics of the training (type, intensity, duration) and the individual’s training status.

Where do we find proteins?

You can keep in mind that animal foods are the best sources of protein. However, you can also get a considerable amount from plant foods.

The best sources of animal protein are:

• Red meat

• Poultry

• Fish

• Seafood

• Eggs

• Dairy products – milk, yogurt, cheeses

The best sources of vegan (plant) proteins are:

• Soy and soy products, soy beans (edamame), tempeh, tofu, soy milk, etc.

• Legumes

• Nuts and Seeds

• Seitan

• Nutritional yeast

Do all proteins have the same value?

The truth is that not all proteins have the same biological value.

Specifically, the proteins we find in foods are distinguished as high and low “quality”, based on their amino acid profile as well as their digestibility.

In simple terms, a protein is considered high “quality” when:

• It includes all essential amino acids in sufficient quantities and

• The body can break it down to use for performing its various functions

Usually, animal proteins (those found in animal foods) are considered high “quality” whereas plant proteins are considered low “quality”.

The good news is that combinations of “low quality” foods can complement the required amino acids, creating “high quality” consumed protein.

Our grandmothers knew something when they made lentils with rice or always accompanied bean soup or chickpeas with bread!

This is particularly important for people following a strictly vegetarian diet (vegans) as these individuals have completely excluded animal foods from their diet.

Therefore, to cover all the essential amino acids that the body needs, they should consume a variety of plant proteins on a daily basis.

Conclusion

The truth is that there is quite a bit of confusion around this question. So let’s put things in order!

Daily protein intake depends on many factors, but the most decisive is your level of physical activity.

The recommended daily protein intake for a healthy person leading a sedentary lifestyle is set at 0.83 g of protein/kilogram (kg) of body weight/day. So if you have an otherwise sedentary life, simply multiply your weight by 0.83 to find the grams of protein you need.

In case you exercise, then you will need an adjustment of your daily protein requirements.

It’s good to consult a clinical dietitian, who is the most qualified to assess your needs based on your goals and recommend the optimal quality and quantity of proteins, always within the context of a balanced diet.

Bibliography

1. Scientific Opinion on Dietary Reference Values for protein. EFSA Journal 2012, 10(2):2557 10.2903/j.efsa.2012.2557

2. Jäger R, Kerksick C, Campbell B, Cribb P, Wells S, Skwiat T, Purpura M. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr 2017 14.