Proteins form the foundation of our bodies; consuming an adequate amount of protein isn’t just important for those who workout, but also anyone who’s interested in staying healthy, in general.
Given the entire range of products that are available to us, today, identifying the protein supplement that fits our own individual health goals can get confusing. What’s the best source of protein? What kind of purity should one look for in a protein supplement? How does one even identify the level of purity?
This article takes a look at the various sources of protein and their different types, along with the advantages or drawbacks of each.
But first, the basics. When choosing a protein supplement, there are 3 main parameters to keep in mind:
1. Protein source: The food from which the protein was purified.
The source could be dairy-based (whey protein), vegan (pea protein), or even from animals (e.g. egg protein, beef protein)
2. PDCAA score: The nutritional quality of proteins is measured by a score called PDCAA, short for Protein Digestibility-Corrected Amino Acid score.1
A higher PDCAA score means that the protein contains high amounts of essential amino acids (the kind that our body doesn’t make) and is easily digested by our bodies. PDCAA scores range from 0 to 1.0, with 1.0 being the highest score possible.
3. Purity: This represents the degree to which the protein has been purified from the food source. It’s normally used to measure the amount of unwanted components, such as sugars and fat, which can be removed in the purification process.
An ‘isolate’ has the highest level of purity, while a ‘concentrate’ is less purified and contains more fat and sugars. While most supplements would come in varying forms of purity, this article mainly concentrates on those of whey protein (as you will read just a bit further on) because of its impact on lactose intolerance.
Here’s a look at the various sources of protein, along with their PDCAA scores and purity.
Dairy Proteins: Whey, Casein & Milk
Dairy proteins are popular protein supplements because they provide all nine essential amino acids (EAAs), called ‘essential’ because our bodies cannot produce them and we need to get them from our diet.
If you’ve noticed, yogurt has two forms: the thicker, solid part that comprises most of it, with the remainder being thinner and runnier. The former comes from casein protein, which makes up 80% of dairy protein, and the remaining 20% is made up by whey protein.
A] Whey Protein
PDCAAS: 1.0 | Ideal
When we think of protein powders, whey protein is probably the first thing that comes to mind – it’s the most well-known.
The reason behind its popularity is that its amino acid profile is better than most other sources of protein. Whey protein has high amounts of branched chain amino acids (BCAAs), which are proteins that make up a large proportion of our muscle and kick-start the process of muscle building. These include isoleucine, valine, and, most importantly, leucine.2, 3 Whey protein is also quickly absorbed by our body, making it especially useful after a workout since it immediately helps with muscle-building and recovery.4
Whey protein supplements can be further broken down into the levels of purity they’re available in:
i. Whey Protein Isolate:
Whey protein isolate is highly purified through a series of filtration steps. This leads to a product that has negligible amounts of fat and carbohydrates, including lactose- a sugar that’s hard to digest for many people (up to 70% of the Indian population), and can thus lead to bloating and indigestion.
Advantage: With its easy digestibility and protein content of over 90%, whey protein isolate makes for a useful protein source for any health goal, even for those who have lactose-sensitivity.
Limitations: Because of the amount of filtration required to get such purity, whey protein isolates tend to be more expensive than other protein supplements.
ii. Whey Protein Concentrate:
Whey protein concentrate is purified to a lesser degree than whey protein isolate. It can contain anywhere between 40% – 80% whey protein, with the rest being a mix of sugars (including and especially lactose) and fats from the milk.
Advantage: Because of the lesser degree of purification involved, it tends to be cheaper than whey protein isolate. A product using an 80% whey protein concentrate ingredient will often provide most of the benefits of whey protein isolate, at a much more reasonable price.
Limitations: People who are sensitive to lactose may experience gas, bloating and other gastrointestinal symptoms, if a lower purity of whey protein concentrate is used, due to the lactose in the product. Labels generally only mention ‘whey protein concentrate’, rarely specifying the percentage of purity, making it difficult to pre-empt its effect on one’s digestion.
iii. Whey Protein Hydrolysate:
Whey protein is broken down into smaller bits (by a process called “hydrolysis”) so that it dissolves better in liquids and is absorbed faster by our body.
Advantage: Proteins, in general, are believed to be digested and absorbed faster after hydrolysis, although this may not hold true for whey protein, specifically (since it’s already fast-absorbing), with studies appearing to have insignificant and conflicting results.5
Limitation: The taste of this protein can be perceived as bitter, so products may be loaded with additives and artificial sweeteners to mask the bitterness.
Note: With the plethora of whey protein supplements available, marketing techniques are only getting more competitive. So here are some claims to look out for:
i] “100% Whey Protein”
Used prominently on countless whey protein supplements, this claim simply means is that all the protein in the powder (which also contains carb and fat) is from whey, and not from mixed sources. It does not mean that the powder is 100% pure protein. This protein powder could be a concentrate or an isolate, depending on the filtration technique used.
ii] “Primary Source: Whey Protein Isolate”
This claim says that the protein is mostly whey protein isolate; the amount of isolate could be just slighter higher than the concentrate in this blend. The ingredients section only requires manufacturers to put the ingredients in decreasing order, but the difference between the two amounts does not need to be stated on the packaging. So if you’re really looking for an isolate, don’t base your decision solely on this claim!
PDCAAS: 1.0 | Ideal
This protein makes up 80% of the protein content in milk and digests very slowly because of its tendency to form clumps – the layers are slowly peeled off during digestion.6
Advantage: When taken at night, the slow digestion ensures that the muscles get a continuous flow of amino acids while we sleep.
Limitations: Its slow digestion does not make it suitable for a post-workout supplement, where the muscles need a quick stream of amino acids. Also, casein does not contain as high a proportion of BCAAs as whey protein.2, 3
3) Milk Protein:
PDCAAS: 1.0 | Ideal
Milk protein is essentially milk that has been purified to minimise the amount of non-protein components, and typically contains casein and whey in the same proportion as in whole milk (80% and 20%, respectively). This can be thought of as milk powder that’s been processed to remove non-protein components.
Advantage: This protein is easy on the pocket, and has a mix of both fast and slow digesting protein.
Limitations: The quantity of lactose and other carbohydrates and fats from milk will almost certainly be higher in milk protein than in whey or casein. Also, since this has only about 20% whey, the rapid increase of amino acids in our bloodstream will be limited.
Vegan Sources of Protein: Pea, Soy & Hemp
A] Pea Protein:
PDCAAS: 0.93 | High
This protein is extracted from the yellow and green split pea, and is becoming increasingly popular as a source of vegan protein.
Advantages: Its PDCAA score makes it easily digestible, with a well-balanced amino acid profile, and means that it can help increase muscle mass, possibly even more than a whey protein concentrate supplement that has a low purity level.7
Limitation: Pea protein may be slightly lower in sulphur-containing amino acids like methionine and cysteine. However, this deficit can be covered by rice, which will provide those proteins.
B] Soy Protein
PDCAAS: almost 1 | High
Isolated from soybean, this protein is also found in tofu and certain mock meat.
Advantages: There have been many reports of the benefits of soy protein on our cholesterol, blood pressure and bone health; some of these claims will, however, need further research to be proven.8-10
Limitations: Soya products tend to contain phytoestrogens, i.e., plant compounds that imitate the effects of the female hormone oestrogen – which has a (albeit low) risk of causing hormonal imbalances. However, it’s important to note that soy protein isolates and most concentrates are unlikely to contain high levels of these compounds, especially if they’re products from reputed manufacturers. Soy proteins also tend to have a bitter aftertaste in comparison to dairy proteins.
C] Hemp Seed Protein
PDCAA score: 0.51 | Moderate
Seeds of the hemp plant are rich in protein, making it an easy source of vegan protein.
Advantages: Hemp seed protein has higher digestibility as compared to soy protein (after being extracted and hydrolysed). This protein has also been investigated for its health benefits on cholesterol levels, hypertension, and appetite, and its free-radical fighting properties. Compared to other vegetarian sources, it’s also relatively rich in arginine, an amino acid that’s required for muscle repair.11
Limitations: Its PDCAA score is only 0.51, largely because it is low in an amino acid called lysine, which forms a large component of the muscle.12 However, this deficit can be made up with meat (for non-vegetarians) or fruits, vegetables and beans.
Animal Protein: Egg & Beef
A] Egg Albumin
PDCAA sore: 1.0 | Ideal
In this supplement, the protein from egg whites, called albumin, is powdered and often flavoured.
Advantages: With a perfect PDCAA score of 1, egg albumin has a very high proportion of the BCAA leucine (which is essential for muscle protein synthesis) that’s probably only second to whey.13 Egg whites are 100% protein and do not contain fat or carbohydrates.
Limitations: Many people may not take to its taste.
B] Beef Protein Concentrate/Isolate:
PDCAA score: 0.92 | High
As suggested by the name, this protein is isolated from beef.
Advantages: This protein provides the benefits of meat without the associated fat or lactose-related digestive issues (as with diary protein).
Limitations: There could be cultural apprehension towards this protein source, and it is definitely not an option for vegetarians and vegans.
Given the variety of protein supplements in the market, choosing the one that’s ideal for us eventually comes down to our health goals, personal preferences and, of course, the actual amount of pure protein we’re getting in a serving. This is one of the rare cases where quantity is quality.
1. Tome D. Br J Nutr 2012, 108 Suppl 2: S222-229.
2. Hall WL, et al. Br J Nutr 2003, 89(2): 239-248.
3. Devries MC, Phillips SM. J Food Sci 2015, 80 Suppl 1: A8-a15.
4. West DW, et al. Am J Clin Nutr 2011, 94(3): 795-803.
5. Manninen AH. Nutr Metab 2009, 6: 38-38.
6. Soop M, et al. Am J Physiol Endocrinol Metab 2012, 303(1): E152-162.
7. Babault N, et al. J Int Soc Sports Nutr 2015, 12(1): 3.
8. Hoffman JR, Falvo MJ. J Sports Sci Med 2004, 3(3): 118-130.
9. Kouris-Blazos A, Belski R. Asia Pac J Clin Nutr 2016, 25(1): 1-17.
10. Messina M, Messina V. Nutrients 2010, 2(8): 855-888.
11. Girgih AT, et al. Nutrients 2014, 6(12): 5652-5666.
12. House JD, et al. J Agric Food Chem 2010, 58(22): 11801-11807.
13. Norton LE, et al. Nutr Metab 2012, 9: 67-67.