About a week ago, I ordered my first jar of a casein protein supplement. Throughout five years of resistance training, I have consumed protein supplements maybe twice. So this purchase was kind of a big deal.

First of all, what is casein protein?

Casein is one of the two main proteins found in milk. Casein makes up approximately 80% of the protein in milk, and the other 20% is whey protein. The casein supplement I ordered is casein that has been separated from milk, dried into a powder, and had an emulsifier (to make sure it mixes well) and flavor (vanilla) added to it.

Why did I do it?

Last month, the International Society for Sports Nutrition (ISSN) published a statement on protein and exercise for the first time in ten years. This publication includes a fairly long list of recommendations, backed with peer-reviewed scientific evidence, regarding protein intake in healthy, exercising individuals. In short, this document recommends that individuals who regularly exercise consume 1.4 to 2.0 grams of protein per kilogram (g/kg) of bodyweight per day to maximize muscle protein synthesis.

I am one of those regularly exercising individuals, but I am not consuming anywhere close to that amount of protein. For me to follow this recommendation, I need to increase my protein intake by about 50 grams per day. That’s about the amount of protein in a 6 ounce boneless, skinless chicken breast OR in two scoops of casein protein powder. The calorie content of these two items is fairly similar. A boneless, skinless roasted chicken breast has about 280 calories, while two scoops of casein protein (mixed with water) is 220 calories.

Why did I choose the protein powder?

The new ISSN review also discusses how protein intake can come from either foods or supplements. And while I would like to think that I will start eating more protein-rich foods, like poultry, eggs, red meat, tofu, cheese, and lentils, I know I’d struggle to add in more protein foods without adding many more unnecessary calories. So I’m trying a supplement to see if it works well as a way for me to meet these protein recommendations.

Is that too much protein?

The protein recommendation for most healthy adults is 0.8 g/kg body weight per day, nearly half of the recommendation for athletes. However, the ISSN recommendation of 1.4 to 2.0 g/kg is still within the range of protein intakes (10 to 35% of total calories) established by the National Academy of Medicine (formerly known as the Institute of Medicine).

The ISSN review also addresses the question of protein safety directly and cites several studies that have assessed the intake of even very high levels of protein (up to 4.4 g/kg/day) on healthy individuals. These studies consistently show no adverse reactions. While people with chronic kidney disease and renal failure, for instance, may benefit from a diet lower in protein than the average adult, healthy active adults may benefit from a diet higher in protein.

Should you buy a protein supplement, too?

While the ISSN statement recommends that healthy active adults consume more protein than sedentary adults, it also recommends consuming protein-rich foods before adding supplements. Choosemyplate.gov includes a list of several foods that contain high-quality protein. Protein supplements can be in the form of “intact” proteins (i.e. not broken down into their amino acid building blocks) like egg, whey, casein, beef, soy, and whole milk, or isolated essential amino acids like leucine. Whether eating protein-rich foods alone or adding in a supplement works best for you, eating enough protein can aid in recovery after working out and complement regular exercise and athletic training.

This blog post was written by Julie Hess, PhD, the 2017 Sylvia Rowe Fellow.