If you have ever walked down a grocery or health food store aisle containing protein powders, you’ve likely found that the sheer volume and varieties of protein supplements can be overwhelming and confusing. How do you choose the right supplement? How much should you consume? Will you be able to absorb and tolerate it properly?
Let’s take a closer look at the importance and requirements of protein and best available sources of protein supplements.
How Much Do You Need?
Proteins are the building blocks of life. They are a class of molecules that are a key structural component of all cells in the body. Protein is needed for growth and repair of the body and maintenance of good health. Additionally, protein is required for energy metabolism, muscle synthesis, cell signalling, immune responses, and enzymatic reactions.
The amount of protein we need is varied and changes throughout our lifetime. The Recommended Dietary Allowance (RDA) for protein is 0.8g/kg of body weight per day for healthy individuals aged 19 and older.1,2 This equates to approximately 55g of protein per day for a person weighing 150 pounds. This is the minimum amount needed to maintain nitrogen balance and prevent protein deficiency.1,2 But recent research indicates that the RDA requirements are not adequate to maintain optimal health, and in fact more protein is needed for women who are pregnant or lactating, older individuals, active people, and athletes.3-5
Animal vs. Plant-Derived Protein is available in a variety of dietary sources. These include foods of both animal and plant origin. Both animal and plant-derived proteins are made up of 20 amino acids.1 Nine of these are not synthesised by humans and are considered essential.1 Therefore, these essential amino acids have to be obtained from the diet.
Proteins from animal sources (eggs, dairy, meat, and poultry) are considered high biological value protein because they contain all nine essential amino acids. Plant-derived proteins (from legumes, nuts, seeds, etc.), on the other hand, typically lack one or more of the essential amino acids and are considered a lower biological value protein.
But when these proteins are combined (e.g.: rice and beans), not only do they provide a complete source of protein, but they also offer a protein profile that is lower in saturated fats and cholesterol.
What Is a PDCASS Score?
Powder supplements offer an easy, convenient, and reliable source of high-quality protein. The most common sources of protein supplements include whey and casein (animal-derived) and soy and pea/rice blend (plant-derived). Depending on the source and purification methods used to manufacture the supplements, a consumer may or may not obtain a high-quality product. The quality and digestibility of a protein is vital considering the nutritional benefits it can provide. It is very important to determine this since the quality of the protein refers to the availability of amino acids that it supplies, whereas the digestibility considers how the protein is best utilised in the body. Therefore, in 1989, the Food and Agriculture Organisation (FAO) along with the World Health Organisation (WHO) in a joint statement recommended utilising the protein digestibility corrected amino acid score (PDCAAS) to determine the quality and digestibility of a protein.6
Anti nutritional factors such as trypsin inhibitors, lectins, and tannins may be present in some protein sources, such as soybean meal, peas, etc., and may cause reduced protein hydrolysis and amino acid absorption.⁶ These factors may be compounded by age, since the ability of the gut to adapt to environmental and dietary insults reduces as we age.6
The PDCAAS score for whey protein is the highest at 1.0 compared to other common protein sources, due to their high content of essential and branched chain amino acids.7 Soy protein isolate is also considered a high-quality protein source (containing all nine essential amino acids) and contains a PDCAAS score of 1.0.7 Pea protein concentrate has a PDCAAS score of 0.89 because it contains lower levels of the sulfur-containing amino acids cysteine and methionine.7
Whey proteins one of the most widely used protein sources for supplementation. Whey protein contains a high amount of the amino acid cysteine. Cysteine has been shown to enhance glutathione levels and has strong antioxidant properties that are capable of helping to prevent damage to important cellular components in the body.6 It also contains a high concentration of branched chain amino acids (BCAA). BCAAs are important for their role in the prevention of muscle breakdown during exercise and tissue maintenance.6
There are different forms of whey protein: Whey Protein Concentrate (WPC) and Whey Protein Isolate (WPI).
WPC is about 80% protein and is created by removing water, lactose, and some minerals. WPI on the other hand contain protein concentrations of 90% or higher since there is significant removal of fat and lactose making it the purest form of protein.6 Unfortunately, the manufacturing process often leads to some proteins breaking down and becoming denatured, reducing the effectiveness of the protein.6 Therefore, even though WPI contains higher protein concentrations than WPC, whey protein concentrate contains more biologically active components. People who are lactose intolerant are able to utilise WPI more readily without experiencing many negative side effects.
Both WPC and WPI can be further hydrolysed. Protein hydrolysates contain di- and tripeptides and therefore can be easily absorbed.
Soy protein contains beneficial phytonutrients such as phytosterols, saponins, and isoflavones. These nutrients have been associated with positive cardiovascular benefits, menopausal symptoms, and osteoporosis.6
Soy protein can also be found in various forms: soy protein concentrate and soy protein isolate. Concentrates have some fat and carbohydrate removed, providing about 70% protein content.6 They have a high digestibility and are usually found in nutrition bars, cereals, and yogurts. Isolates are further refined, lacking dietary fibre but provide 90% protein content.6 They are easily digestible and can be found in protein supplements and infant formulas.
Pea/rice protein blend is recommended if you have a milk protein allergy/sensitivity, are avoiding soy products, or consume a vegetarian diet. Including a pea/rice blend protein powder is an alternative to whey protein, has a high PDCAAS score, and provides all nine essential amino acids.
Pea protein also contains a variety of phytonutrients such as polyphenolics, which may have antioxidant activity; saponins; and galactose oligosaccharides, which may demonstrate beneficial prebiotic effects in the large intestine.8
Whether you are using these supplements as a meal enhancer, snack, or a post workout drink, adding a high-quality protein supplement will help meet your daily protein needs. Metagenics provides a variety of protein options; work with your healthcare provider to figure out the amount and type of protein you need for optimal health.
About Nilima Desai
MPH, RD, Metagenics Manager, & Medical Marketing Nilima Desai is a Registered Dietitian who received her undergraduate degree from California State University Long Beach in Nutrition and Dietetics and her Master’s in Public Health Nutrition from Loma Linda University. She has over 14 years of experience providing medical nutrition therapy in diabetes, renal disease, weight management, and vegetarian nutrition. She also served on the board of the Renal Practice Group of the Academy of Nutrition and Dietetics from 2012-2016 as the Membership Chair. Her passion about living and teaching a healthy lifestyle led her to collaborate with a nephrologist on creating the Pocket Dietitian app, which offers the user personalized, easy-to-use dietary prescription on conditions such as diabetes, hypertension, renal disease, weight management, etc. In her free time she runs half marathons and shuttles her two kids to their activities.