This article helps you get answers to the following questions: What are proteins? What are proteins made of? What foods should you eat? And how much protein should you consume?
What are proteins?
Proteins are a type of macronutrient that the human body needs to move, grow and overall stay alive. All living things need proteins and other types of nutrients to function. Animals get nutrients through the foods they eat, while plants produce some nutrients and take others from the air and soil.
Did you know that about 1/6 of your body’s total weight is protein? Your body needs protein to grow tissue and repair itself. Also, after water and possibly fat (depending on your lifestyle), protein is the most abundant material in your body.
What are proteins made of?
Your body has many types of proteins that it uses in different ways. For instance, some proteins are involved in the process of growth, others in the process of reproduction, and third play a part in digestion or ageing. When the protein is produced in the body, much of its production happens in the liver.
Each protein is made up of groups of molecules called amino acids. And each amino acid molecule consists of atoms of hydrogen, carbon, oxygen, nitrogen and sometimes sulfur. Amino acids are attached to one another by peptide bonds which create long chains of proteins. The building blocks of all proteins present in the human body are 20 kinds of amino acids, as there are more than 100 kinds found in nature. Each type of protein is a combination of amino acids (incl. many repeating ones) in a specific pattern which determines the shape and function of the protein. Most common proteins include more than 100 amino acids – for instance, haemoglobin is a protein found in red blood cells, which is made of 287 amino acids.
The amino acids in the human body are divided into two groups: essential and non-essential. Essential amino acids are the amino acids you need to supply through your diet. Whereas the non-essential amino acids are not an essential part of your diet because your body can synthesize them. Examples of essential amino acids are Valine, Histidine, Leucine and Threonine. Non-essential amino acids are, for example, Alanine, Arginine, Serine and Tyrosine.
Plans can produce all 20 types of amino acids that they need, while the human body can make only 11 of the 20 required types. This means that you need to supply your body with the other 9 types through the food you eat.
Fibrous & Globular proteins
All proteins are divided into two big groups: fibrous and globular.
Fibrous proteins have a shape similar to that of fibres. They’re made up of lengthy chains of amino acids arranged in sheets or strands. These proteins are present in the fur, scales, quills, nails, antlers, feathers, horns and hooves of animals. They’re also a part of the skin (incl. human skin), bone, tendons and cartilage. Examples of fibrous proteins include:
- Collagen and elastin can be found in the deeper layers of the human skin.
- Myosin and actin play a significant role in helping muscles to move.
- Fibrin keeps your body from losing too much blood because it helps form blood clots.
Globular proteins have a globe-like shape, and their amino acid chains are folded into a round structure. These proteins have various functions, for example:
- Immunoglobulins (a.k.a. antibodies) fight all harmful materials (e.g. germs and bacteria) that enter the human body.
- Most enzymes are globular proteins, which help control how quickly chemical reactions happen in the body.
- Hormones tell cells and body parts to perform specific tasks – for instance, when the body should grow or stop growing. The hormones glucagon and insulin help keep blood sugar levels at normal values.
- Haemoglobin is a transport protein helping transport oxygen from one place in the body to another.
What are the sources of protein?
Foods from animal sources
You can supply your body with a good dose of protein by eating various foods from animal sources. For instance, foods such as meat, fish, eggs and dairy products (e.g. milk, cheese and yoghurt) are rich in protein and can provide your body with all the essential amino acids.
However, the fact that meat is a good protein source doesn’t mean that you should eat large amounts of it daily, especially if we’re talking about processed meats. Processed meats like bacon, hot dogs, sausages and cured ham are less healthy than non-processed food. They’re also linked to diabetes and heart diseases. Therefore, stick to non-processed meat like chicken fillets or beef steaks.
Foods from plant sources
Plant foods also contain protein but usually lack some essential amino acids and have low levels of them. If you don’t eat meat, poultry or fish, then make sure your diet is rich in different plant foods. Eating a mix of different plant foods daily will ensure that your body gets all the essential amino acids it needs. Examples of good plant protein sources include seeds, nuts, tofu and legumes.
Protein powder
Another popular way to add extra protein to your regular diet is using protein powder. Protein powder usually contains soy, whey or casein protein. Bodybuilders and other athletes often use it, but it can also be a good source of protein for vegetarians and vegans. You can include protein powder into your diet by preparing shakes and smoothies or adding it as an ingredient in cakes, brownies, chocolate chip pancakes, and other foods. One of my favourite protein powder brands is Scitec Nutrition because their products often have added amino acids and great taste and are gluten-free.
How much protein do you need?
The amount of protein you need a day depends on many factors – e.g., age, gender, lifestyle and daily activity.
The recommended daily dosage of protein for an adult is based on body weight. Basically, you should eat 0.8 gr of protein for every 1 kg of body weight. But if you do sports or bodybuilding, then your body needs higher amounts of protein (e.g., 1.5 – 2 grams of protein per 1 kg of body weight).
If you don’t eat enough protein or the proteins you consume don’t provide all the essential amino acids, you may experience various health problems. For example, people who don’t supply their bodies with enough protein often feel tired and weak. The lack of protein can also cause oedema, anaemia or issues with the body’s red blood cells.
Protein-energy malnutrition is very common among children in third countries and adults worldwide, and it occurs when a person gets too few calories, too little protein, or both. Popular severe forms of malnutrition in children are Kwashiorkor and Marasmus:
- Kwashiorkor appears when you eat primarily starchy foods such as cereal grains, and as a result, your body gets enough calories but not enough protein.
- Marasmus occurs when your body doesn’t receive enough protein and calories.
Lastly, consuming too much protein is also not a great idea because it can create kidney issues. If you overeat with protein, you probably don’t get enough of the other types of macronutrients. For instance, the regular lack of carbohydrates can affect your health in the long run because your brain needs carbs to function.