Whey protein? Soy protein? Which do I choose? Which is better?
Choosing the right protein supplement to stay healthy and to build muscle can be a challenging task. There are so many brands on the market that it can be hard to decide what is best for you.
But we are not going to talk about brands here.
If you take a look at the protein supplements for health that are available on the market, there are those with whey protein, some with soy protein and some that are a mix of both.
On the other hand, there are those that discard protein supplements as useless, and instead choose to increase their intake of animal protein (fish, chicken, red meat etc.).
But which is better? Is there really a difference?
Let’s explore which form of protein is better – whey or soy?
How Protein Helps You
Proteins are nitrogen rich compounds that are primarily composed of amino acids. They are essential in maintaining muscle mass, in synthesis of hormones, hemoglobin production, and also in enzyme production.
Proteins should form a reasonable portion of your daily diet. A diet that is low in protein in children leads to a condition called kwashiorkor.
Our body needs a total of 20 amino acids, of which 8 have to be obtained through diet alone. These are called essential amino acids. The remaining 12 are non-essential as they are synthesised in the body.
Protein has mostly received attention as a ‘supplement’ that helps in muscle growth if you are a bodybuilder or an athlete. The fact is that it is also needed for elderly people who are unable to consume enough food, or for people convalescing from an illness.
The biological value of a protein is a reflection of how much is available to be utilised by the body once it is consumed.
Those with a higher value have a better supply of amino acids. Animal protein is generally better than vegetarian protein in this regard.
Whey protein tops the list of proteins with the highest biological value, with a score of 104. Egg scores 100, milk protein has a score of 91, while beef has a score of 80. The table below lists the biological value of commonly consumed proteins (adapted from here).
Protein Digestibility Corrected Amino Acid Score
This is the preferred way to score how good a protein is for humans. It basically looks at the percentage of essential amino acids within the protein. While the scoring system does have some limitations, a score of 1 makes it a good protein score. This has been included in the table below as well.
What Is Whey Protein?
Whey protein is derived from milk. It is the liquid that remains after curd removal during cheese manufacturing.
Whey protein forms 20% of cows milk, while casein forms the rest. It is probably the most widely used protein in body building supplements.
There are 3 types of whey protein – whey powder, whey concentrate and whey isolate.
Whey powder is what is used in most products across the market. They are also used in bakery items and in salads. They have a lower concentration of protein (around 11 to 15%) and a higher content of lactose.
Whey concentrate contains anywhere between 25 to 89% protein with 10 to 55% lactose. Whey concentrate contains highly biologically active components that make it popular in most muscle building supplements.
Whey protein isolate (WPI) contains over 90% protein, with very little lactose. If you are lactose intolerant and looking for a good protein supplement to build muscles, then whey isolate is what you should be choosing.
Whey protein intake leads to a faster spike in blood amino acid levels compared to casein.
What Is Soy Protein?
Soybean has been popular in chinese culture as a valued food since 2838 BC. Its true protein value was only discovered years later, and it is now regarded to be equivalent to animal protein (see table above).
Soy has a high concentration of branch chain amino acids, and is lactose free. This makes it a great vegan source of protein.
Soy protein is also available in 3 forms – flour, concentrate and isolate.
Soy flour has 50% protein and is poorly refined. Soy concentrate contains 70% protein, while soy isolate contains 90% protein. Soy isolates are commonly used in protein shakes and in infant foods.
Whey Protein Vs Soy Protein – Which Is Better?
Well, there is really not much difference. If you wish to train to build muscle, then there would be a larger selection of whey isolate based protein supplements on the market as opposed to soy protein based.
When it comes to general health, it would depend on whether you have lactose intolerance or not, and whether you are vegan.
If you are lactose intolerant, then choose a soy based protein supplement. If you are vegan, then this would be your choice as well.
When it comes to building lean muscle mass, studies have not shown much difference.
A similar benefit was seen in older men as well, with not much difference between the two.
High intensity functional training studies have also found no difference between whey protein and soy protein when it comes to changes in body composition and muscle bulk.
However, if you look at some of the best protein supplements for general health that are available in the market, they are often a blend of proteins. This is because whey protein and soy protein have a different amino acid profile and digestion rates, and combining both of these with casein may provide greater benefits to your health than just one.
So the bottom line is this – whey protein is widely available, but soy protein is just as good if you are vegan and lactose intolerant. Be it for muscle building or general health, you could choose one or the other, or even a blend of the two with casein.