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Protein supplements can come from numerous sources now. While supplementation is not mandatory for consuming sufficient protein, it is more convenient and less volume of food to consume (which I find a major benefit when in a caloric surplus). However, it is rarely discussed which source offers the most benefit overall as well as the most benefit per cost. Evaluating four protein options based on these criteria, I will present what I find to be the best option, including the best vegan option.
Best-selling on Amazon: 10.99/lb.
Whey protein is the standard protein supplement that people use. It is typically made from milk or using the watery waste product from cheese production. It is known as a fast digesting protein because it is digested completely within one hour and also offers a full amino acid profile (otherwise known as a “complete protein” source). Leucine and glutamine are two amino acids that make up a relatively high percentage of whey (10% and 17%, respectively). Leucine is unique in that it activates muscle protein synthesis—very important after muscle breakdown from exercise. Glutamine is depleted in the muscle after exercise and more glutamine in the muscle is correlated with more muscle protein synthesis; therefore, glutamine repletion can also lead to higher muscle protein synthesis. Glutamine supplementation can also increase growth hormone. All of these factors make whey a quality choice for post workout supplementation.
Another area whey has shown promise is weight loss and body composition (lower body fat, more lean muscle). Whey protein has been compared directly to plant proteins such as soy to see the direct, experimental difference for weight loss and body composition, rather than the indirect difference by comparing the people that report eating more plant protein vs. animal protein (a little skewed due to people consuming plant protein having generally healthier lifestyles overall, and the animal protein group counting hot dogs, pepperoni, and lunch meat as “meat”). One study comparing whey and soy directly found whey provided more improvements in body composition than the soy, such as increases in lean muscle mass and significant reductions in body fat and waist circumference. This was mainly due to reduced appetite and therefore lower calorie intake (despite the subjects not even dieting or training to create a calorie deficit on purpose; they were just eating as they pleased).
Whey has many other health benefits beyond protein supplementation. Below are a few that I have paraphrased from an article (by Tsutsumi and Tsutsumi) to help make them easier to understand:
- Cancer (particularly colon and breast cancer)—several studies have looked at whey in cancer prevention. The effect is believed to be due to the antioxidant and immune-enhancing effects.
- Hepatitis B and C—whey improved liver function markers and increased immune cell (such as natural killer cell) activity.
- Heart disease and high blood pressure—a study group receiving fermented milk and whey protein concentrate had improved blood lipids (higher HDL and lower triglycerides) as well as lower blood pressure than the control group.
- Osteoporosis—a component of whey protein can suppress bone breakdown while also stimulating creation of bone cells that lay down more bone.
- Stress adaption—whey improved cognitive performance and mood in stress-vulnerable subjects.
Whey concentrate is the cheapest form of whey and is not any worse than the more expensive whey protein isolate. The difference between these two forms of whey is that whey concentrate is about 80% protein with the fat, lactose, and cholesterol still in the powder; whey protein isolate goes under more filtration to remove more of that fat, lactose, and cholesterol, leaving the powder with 90% protein, but requiring a higher price because of extra processing. Whey concentrate offers all the benefits mentioned above at a cheaper price, leaving no need for spending extra on whey protein isolate unless you are lactose intolerant (it still contains very small amounts of lactose, but low enough that lactose intolerant individuals could consume it). I recommend the whey concentrate in as much bulk as you can find it because that will likely be the cheapest per pound as well. Whey does not expire for (usually) at least a year or more after the manufacturing process, and if you aren’t exercising often enough to use up the powder within a year, maybe it’s time to step it up and increase your exercise frequency.
Best-selling on Amazon: 12.49/lb.
Casein protein is the other protein portion of milk (80% of the protein in cow’s milk). It is the main protein in cheese and greek yogurt and is also considered a complete protein. Casein offers a slightly lower percentage of leucine (~9%) and a higher glutamine percentage (20%) compared to whey. The main difference between casein and whey is that casein clumps up in the stomach and takes several hours to digest—providing a steady stream of protein. While the amino acids still offer the same benefits as mentioned in the whey section, the longer release time doesn’t provide as intense of a response of those benefits. The longer release instead provides protein over a long period to maintain protein synthesis and prevent muscle wasting. The major time this would be useful is while sleeping, since you are fasting for several hours.
One unique benefit that casein offers is prevention of tooth decay. One study found casein can significantly inhibit enamel erosion (compared to other proteins and fluoride alone). This could be due to the higher amount of calcium in casein protein compared to other proteins.
Micellar casein is the best casein for the long digestion time. Other casein forms such as calcium caseinate or hydrolyzed casein don’t clump up as well, leading to significantly shorter digestion times. With the main benefits coming from the steady stream of protein from slow digestion, micellar casein is the form you want.
Best-selling on Amazon: 7.2/lb.
Soy protein is derived from the soy bean. In the manufacturing process, the soybean meal is dehulled and defatted to create soy products that are high in protein such as soy flour, soy concentrate, and soy isolate. I’ll focus on the soy isolate as it is the form often found as protein powder supplements. Soy protein isolate is about 90% protein due to the extensive processing (similar to whey protein isolate). It is often the protein added to fake meat sources to give them more texture and protein, as well as acting as an emulsifier in many other products.
Soy is one of the few non-animal sources of protein that offers a full amino acid profile (“complete protein”). The percentage for leucine (6.6%) is a decrease from both whey and casein, while the glutamine (21%) is an increase. Soy protein has a relatively quick digestion rate (very slightly slower than whey). Its digestion rate in combination with being a complete protein makes it another quality choice for post workout supplementation. However, in a study that compared soy protein vs dairy protein, only the dairy protein group had increases in protein synthesis (measured 2 hours after ingestion). The study had the diets matched for total calories and macronutrient (protein, fat, carbs) consumption, making the major difference the amino acid profile of the proteins. It seems the ~3% difference in leucine between soy and whey makes a significant difference when considering protein synthesis.
Another study looked at strength gains in the elderly (average age of 61) during a resistance training program with: increased protein intake using dairy protein to supplement, increased protein intake using soy protein to supplement, or no increased protein intake. The results of the study found that the dairy protein group and even the no protein group had significantly more strength gains (about 30% more) than the soy group. The authors hypothesize that these results may be due to the estrogenic properties of the low amount of isoflavones in soy proteins.
The health benefits of soy have been debated for decades. There are two sides that most people fall into: either soy is a superfood that offers great health benefits, or it’s garbage and has detrimental effects. I will try to present the information objectively because I want to present the facts, not defend one side or the other. As mentioned in the previous paragraph, soy can have estrogenic properties from the isoflavones. Soy was first considered healthy for heart disease, osteoporosis, and cancers due to the lower incidence of these diseases in the Asian population that consume more soy. However, the majority of the soy is consumed as fermented products (natto, tempeh, miso, etc.) and the health benefits could be more due to the bacteria from fermentation (like probiotics).
One study in Japan looked at bone health and osteoporosis prevention related to soy consumption and found that consuming adequate amounts of soy was beneficial for bone health. This is likely due to the estrogenic effects, as estrogen has been found to have similar benefits for bone health and osteoporosis prevention. Another study looking at the effects of soy supplementation on gene expression in breast cancers concluded that soy can adversely affect gene expression, particularly in a subset of women. A third study was a meta-analysis on the risk of heart disease and soy consumption. The meta-analysis found very limited evidence to suggest that soy consumption helped to prevent heart disease.
If you’re considering taking soy protein, soy protein isolate is the form of soy protein you should get. Unlike with whey protein, there is a significant difference between the amounts of protein in soy protein concentrate vs. soy protein isolate (8 g vs. 23 g per serving). The isoflavones in each form are about the same though, so if your goal for taking soy protein is the isoflavones, either form is a good option.
Best-selling on Amazon: 23.93/lb.
Pea protein is obtained by drying and grounding peas into fine flour, mixing it with water, and removing the fiber and starch, leaving mostly protein with some vitamins and minerals. This paste is then dried and ground into a fine powder, creating pea protein isolate.
Peas are another one of the few non-animal sources of protein that offers a full amino acid profile (“complete protein”). However, even though it does contain all the amino acids, it is very low in a few essential amino acids, so it shouldn’t be anyone’s sole source of protein. The percentage for leucine (8.6%) is significantly higher than soy, and comparable to casein protein. The glutamine (17.5%) is similar to whey and a relatively large decrease from casein and soy. Pea protein is the closest vegan option to whey, in terms of these two amino acids. The digestion rate is a bit slower than soy, but still significantly faster than casein. Most people describe pea protein as a “fast-intermediate” digesting protein.
Pea protein was studied directly against whey protein and a placebo to look at the effect on arm circumference during a 12 week training program. The pea protein group had more arm gains than the other two groups, but the effect was not statistically significant. However, the numbers were likely misleading due to:
- The timeline for the measurements was not given, so we can’t tell how long after the workouts the circumferences were measured. This is important because there is a cell swelling after resistance training that can last almost three days! The cell swelling is likely due to inflammation and cell hydration. Without waiting at least three days to take measurements, it’s difficult to say any apparent size increases are from muscular gains or inflammation and water.
- The study was sponsored by the company that produces the pea protein used by the subjects. This doesn’t necessarily mean that the company did anything to influence the data or conclusions on purpose, but it’s always more difficult to have an objective study when the sponsors have a conflict of interest like that.
Another interesting result from this study that makes the size gains questionable—both the whey and placebo group had more strength gains than the pea protein group. One would imagine that if subjects gained more muscle, they would also gain more strength, but that was not the case.
When consumed with a soluble fiber, cholesterol benefits have been seen in one study looking at pea protein. Another study found 20 grams of pea protein to be useful in controlling pre and post meal blood glucose. A third study confirmed that pea protein can have antioxidant, anti-inflammatory, and immunomodulating properties, mainly through inhibition of pro-inflammatory cytokines and stimulation of the gut mucosa immune response. All of these studies add to the extra benefits that pea protein can offer.
Pea protein really only comes as one type, and that’s pea protein isolate. It’s usually made from yellow or green field peas because they are high in protein (relative to other peas, like sweet peas). Without isolating the protein from the field peas, the powder would only be about 25% protein; stick with the isolate form for pea protein.
Now at the end of the research, a recommendation can be made. In my opinion based on the research, whey is the best choice for total benefit as well as benefit per cost. This is mainly due to the support whey protein has for muscle building, body composition, and several other health benefits. The best vegan option is a bit more difficult to decide. Both soy and pea protein have purported benefits to their consumption, but also mixed research on those benefits. Due to this mixture of research, I would recommend pea protein as the better protein for overall benefits, but soy as the better option for benefit per cost. Soy protein is significantly cheaper than pea protein, making it better for the cost averse supplementers out there—assuming that they aren’t bothered by the potential detrimental effects of soy.
- For total benefit AND benefit per cost, whey protein is the best option overall
- For vegans, pea protein is the best option for total benefit
- Soy protein the best option for benefit per cost
- If you are getting any other flavor besides chocolate, question your life choices
Tahavorgar, Atefeh, et al. “Whey protein preloads are more beneficial than soy protein preloads in regulating appetite, calorie intake, anthropometry, and body composition of overweight and obese men.” Nutrition Research (2014).
Thomson RL, Brinkworth GD, Noakes M, Buckley JD. “Muscle strength gains during resistance exercise training are attenuated with soy compared with dairy or usual protein intake in older adults: A randomized controlled trial.” Clinical Nutrition (2015).
Babault N, Paizis C, Deley G, et al. “Pea proteins oral supplementation promotes muscle thickness gains during resistance training: a double-blind, randomized, Placebo-controlled clinical trial vs. Whey protein.” Journal of the International Society of Sports Nutrition 12:3 (2015).
Sirtori CR, Triolo M, Bosisio R, et. al. Hypocholesterolaemic effects of lupin protein and pea protein/fibre combinations in moderately hypercholesterolaemic individuals. Br J Nutr. 2012 Apr;107(8):1176-83.
Smith CE, Mollard RC, Luhovyy BL, Anderson GH. The effect of yellow pea protein and fibre on short-term food intake, subjective appetite and glycaemic response in healthy young men. Br J Nutr. 2012 Aug;108 Suppl 1:S74-80.
Ndiaye F, Vuong T, Duarte J, Aluko RE, Matar C. Anti-oxidant, anti-inflammatory and immunomodulating properties of an enzymatic protein hydrolysate from yellow field pea seeds. Eur J Nutr (2012) 51: 29.