Different sources of protein

Most people probably primarily think of classic protein sources such as meat, fish, poultry, eggs, and concentrated dairy products like cottage cheese, quark, and cheese when they think of protein-rich foods. But we get protein from many places. In addition to classic sources, legumes (beans and lentils) and products made from legumes such as tempeh and tofu, various types of grains and products made from grains such as bread and pasta, as well as vegetables, nuts, and seeds are also rich in protein.

Below is a list of how much protein there is per 100g and how much you need to eat to get 30g of protein, which can be considered a reasonable goal per meal/occasion. 

TABLE with content per 100g and quantity for 30g                             

Source: slv.se

Is there a difference between different sources?

As mentioned, protein is found in many different sources, and they differ in many ways. So, to answer the question, even briefly, one needs to specify what is meant by difference: is it a question of taste, consistency, nutritional value, satiety, uses, or absorption rate, etc.?

Perhaps you have heard of terms like complete or incomplete protein or that protein has different bioavailability or biological value. These can be called quality aspects of protein. To clarify this, a deeper dive is required, which you can read more about here.

If we stick to simpler answers here, we can start by distinguishing between whole foods such as meat, fish, poultry, eggs, legumes, vegetables, etc., and protein supplements such as protein powder or products with concentrated protein (e.g., bars, drinks, protein pudding, etc.).Whole protein foods – here you get many other nutrients in the same bite, which is smart. From a pure protein perspective, you don't need to think about variation when it comes to animal sources, but if you eat completely vegan, you should make sure to consume both legumes and grains (read more in the detailed explanation). When it comes to protein sources as whole foods, it's smart to vary and use different sources, not so much for the protein itself (except when you are vegan) but precisely for all the other things found in protein sources. For example, eating fatty fish to get important omega-3 fatty acids, not eating too much red meat and processed meats as it has been shown to increase the risk of gastrointestinal cancer, and also using plant-based protein sources such as beans and lentils to get fiber, minerals, and important bioactive substances in the same bite.

The short answer to whether it matters which protein powder/supplement you use is no.

Concentrated protein sources/protein supplements – here it is first and foremost good to remember that these, unlike whole foods rich in protein, generally contain little more than just protein. Even if they are derived from, for example, milk or soybeans, which are nutritious in themselves, these nutrients are not retained in the purified and concentrated source. This does not mean it is bad, only that you must remember to get all those important substances from other sources, in other bites.

The short answer to whether it matters which protein powder/supplement you use is no. You can easily base your choice on taste preference.

Certainly, there are measured differences in, for example, absorption rate and bioavailability, but in practice, it is questionable whether it makes any difference at all.

Here is a brief description:

Other nutrition: Since they are concentrated sources of protein, there isn't much other nutrition in pure protein powder. The purer it is, the fewer nutrient residues remain. (isolate is purer than concentrate)

Protein quality: Animal-based (milk, beef, egg) are complete, while plant-based (soy, pea, oat) are not. However, this is not very relevant if you eat a varied diet.

Satiety: All protein contributes to satiety, and satiety is difficult to measure, so it is very much a subjective experience and depends heavily on the context, what else you eat, etc. But, casein is known to be the protein concentrate that provides the best satiety, while whey provides slightly less satiety.

Absorption and absorption rate: whey protein is known for having a high absorption rate, i.e., being fast, while casein, on the contrary, is a bit slower and takes a little longer to be absorbed by the body. This has made whey very popular and effective in connection with exercise, while casein is usually sold as something to take at other times and in the evening to have absorption overnight. And yes, studies can show differences in absorption. But, the question is whether it makes any difference in practice and for your results. Here it is more doubtful. You can easily choose what you think suits you.

Taste – Taste is subjective, but there is a big difference between different protein powders depending on the source. The purer a protein powder is (isolate is purer than concentrate, for example), the less taste it has. Milk-based protein powders such as whey and casein are often perceived as tastier than plant-based ones from, for example, soy, beans, or oats. The latter taste a bit more floury and grainy. Milk-based ones give a more milk-like taste and consistency, apart from what is called "clear whey," which is completely clear and does not taste like milk at all.

Consistency: There is a big difference in consistency between different sources. Clear whey is transparent with a water-like consistency….

Usage: Casein is very suitable for baking and can [KA4] 

In-depth, is there a difference between different sources? 

Perhaps you have heard of terms like complete or incomplete protein or that protein has different bioavailability or biological value. These can be called quality aspects of protein. To explain or understand this, we need to go back a bit and delve into what protein is. Protein is a type of nutrient or molecule that, in turn, consists of long chains of so-called amino acids. One can compare it to Lego and Lego bricks, where amino acids are the Lego bricks, and when you put them together to form, for example, a house, it is called protein.

There are 20 different amino acids, i.e., Lego bricks. Depending on which amino acids, how many, and in what order they are arranged, different proteins are formed. That is, just like with Lego: depending on how you combine different Lego bricks, you can build different things. In the same way, proteins also acquire different functions (i.e., whether it is a hormone, transport protein, receptor, etc.) depending on which amino acids they are and how they are put together.

When we eat something that contains protein, we are thus eating "Lego constructions." In the gastrointestinal tract, they are broken down into individual Lego bricks, i.e., amino acids. These are then absorbed into our bodies. Once inside the body, we put these amino acids together again and build the type of protein we need, according to our instructions/descriptions (if we eat fish, for example, the protein in the fish is amino acids put together to form the protein substances that a fish needs). We might eat a Lego house but then use the Lego bricks to build a boat.

SO, back to quality, bioavailability, and biological value. When protein sources contain all the 20 amino acids we need and in amounts suitable for our bodies, it is called complete or having a high biological value. This generally applies to animal protein sources. We are also good at breaking down and absorbing these, which is why they are said to have high bioavailability. 90-100% of the protein we consume in the form of animal sources can be broken down and absorbed by the body. When it comes to plant-based sources, we only absorb about 80-90%, meaning the bioavailability is 80-90%.

Plant-based sources also have a lower biological value and are often referred to as incomplete. This means they do not contain all the amino acids we need, at least not in sufficient quantities. This may not sound good, but in practice, it is not a problem. If you combine different sources, the total becomes good. Generally, it can be good to remember to combine grains and legumes if you do not eat any animal products at all. They contain slightly different amino acids, and the combination becomes complete.

For those who eat animal products, at least a little, there is no need to worry about bioavailability, completeness, etc. Nor if you follow one of our basic recommendations: to eat a varied diet.