These are one of the most popular products currently on the market and arguably for good reason. An adequate protein intake, as you have learned, leads to almost innumerable benefits compared an inadequate one and protein powders can play a role in allowing you to get all you need.
The most common form of protein powder is whey protein, with other milk based products, egg, soy and vegan alternatives making up the rest of the market. In order to choose between the various options, it can be worth considering the Biological Value (BV) of the powders. BV is a measure of the proportion of absorbed protein from a given source which is incorporated into bodily proteins, measured by comparing the amount of nitrogen (which you will remember is a part of amino acid structure but not the structure of monosaccharides or fatty acids) in the protein, with the amount of nitrogen excreted after consumption in a fasted state, to work out the amount of nitrogen retained. If nitrogen has been excreted then amino acids have been broken down to make something else, whereas retained nitrogen implies retained amino acids. The percentage of stored amino acids is then used to create a score.
This is an imperfect scale (the measurements are not 100% accurate, and the BV would likely change from person to person, and even within the same person after eating other things they become altered at different overall protein intakes) but it’s a practically useful metric for determining which protein powder is likely to provide the most nutritional benefit.
Egg protein (from whole egg) is typically used as a baseline as it has a very high level of essential amino acids, and almost all of its nitrogen is retained. This makes it the perfect score of 100 against which other proteins can be compared. Below is the BV of the most commonly used protein powders:
As you can see, whey-based protein powders win, followed by egg, milk and then the others. Worthy of note, however, are a few key facts:
These are, much like micronutrients, nothing more than convenient and affordable options in the search for an adequate intake of regular nutrients. None of them will have any meaningful impact over and above what would be provided by whole food protein sources, and in fact they lack many of the micronutrients provided by the latter. As such, protein powders should not be viewed as a supplement which will provide any benefits per se and nor should it be viewed as an alternative to whole food protein sources.
With that said, these products require no cooking or refrigeration, are relatively cheap and can be enjoyable, so they can be an option alongside an otherwise whole food diet. Consuming an adequate amount of protein throughout the day is key to optimal health and these powders can be considered a viable tool for achieving this.