Written by Ben Carlisle
Last updated on: Sep 18, 2022
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With more and more people moving towards a plant-based diet, pea and rice protein are increasingly being used in sports and fitness supplements. Both of these plant proteins are amongst the leading vegan supplements to support fitness and athletic performance goals.
Below we will look at each of these protein powders. Looking at how they are made, the benefits they offer and any considerations you should make before purchasing one or the other.
Pea protein is extracted from yellow peas. While yellow peas are part of the legume family, the same as green peas, they are not genetically the same (1, 2). Green and yellow peas are varieties of the "Pisum sativum L". This field pea is found all over the world and is a staple in traditional diets.
Yellow peas taste different from green peas, with a mild, more nutty flavor. The extracted pea protein has a less discernible taste, which makes it an excellent ingredient in flavored protein powders.
Apart from its uniquely bland flavor profile, pea protein has some other major benefits. As a GMO-free crop it’s both gluten-free and has good levels of every essential amino acid except methionine (some refer to pea as a complete protien, but this is a debated issue). Pea protein also provides an impressive range of nutritional components to enhance human health.
Pea protein is obtained by de-husking the pea and then milling it. What is left after milling is raw flour made up of soluble fiber, protein, and starch. This flour is then put through a wet filtration process and then subjected to a centrifuge, producing a solution from which the protein is isolated by way of heat.
The centrifuge forces the wet flour through a filter to separate the fiber, carbohydrate, and fat molecules from the protein molecules. The resulting protein concentrate still contains a large amount of excess carbohydrate and fat. So, the concentrate undergoes a further process to remove these carbohydrate and fat molecules.
The protein concentrate is heated to its isoelectric point, which is the point at which the molecules have no net electric charge, and the pea protein is then precipitated out of the solution. This is accomplished through ion exchange or a cross-flow microfiltration process after which the solution is dried to form a white-beige powder (3).
The isolated pea protein contains every essential amino acid, including abundant quantities of branched chain amino acids (BCAAs) . These 3 BCAAs; leucine, isoleucine and valine play an important role in muscle protein synthesis.
The only essential amino acid which pea does not have in good levels is methionine, this leads many to say it does not deserved to be called a complete protein as it lacks the minimum level of methionine required to be classified as such. Interestingly, this is an amino acid brown rice protein has good levels of. This is why pea and rice protein powder is often combined in a blend. Let's look at brown rice protein in more depth.
Brown rice protein is obtained from normal paddy rice. The rice is passed through a machine which removes the hull and leaves the kernel and bran layers intact. The brown rice is then ground to produce gluten-free flour. The rice flour is then hydrated to form a solution which is treated with heat-stable alpha-amylase to separate the protein from the carbohydrate and fat content (4, 5).
The resulting protein concentrate is dried to form a protein-rich powder containing approximately 79% of total amino acids. The resulting brown rice protein consists of up to 36% essential amino acids and approximately 17% BCAAs (6).
When compared to soy and whey protein powder, brown rice protein powder contains more methionine than either one. It does not, however, contain good levels of lysine. It is important to note, just like rice fills the weakness in the amino acid profile of pea, pea fills the weakness in the amino acid profile of rice.
Although both pea and rice protein powders contain the nine essential amino acids, pea protein lacks methionine and rice lacks lysine in sufficient quantities for optimal health. The recommended essential amino acid intake for humans is as follows (8):
To ensure you get the quantity of essential amino acids required from your protein powder, pea and brown rice protein are combined to balance the essential amino acids, specifically methionine and lysine.
As an essential amino acid, Methionine is not manufactured by your body but must be obtained from your diet. It contains sulfur and is utilized by the body to build proteins. It is also required to create many other molecules in the body. The antioxidant glutathione and the SAM molecule utilized to change and modify DNA are just two of the many essential functions that methionine is involved in.
Your body’s ability to absorb calcium as well as its ability to create collagen is dependent on lysine. Without sufficient lysine, your body’s ability to maintain your bones and connective tissue as well as create skin, cartilage, and tendons will be compromised.
The BCAAs are; leucine, isoleucine, and valine. They have a branched molecular structure which is utilized for energy and metabolized by the body and used as sources of muscle energy. This branched structure is why they are referred to as the branched chain amino acids. The BCAAs promote muscle protein synthesis as well as reduce muscle damage and degradation during resistance training.
During endurance exercises, the BCAAs fulfill the same function as glycogen, providing a source of energy to the muscles and suppressing the production of lactic acid. Pea protein contains 8.4grams of leucine, 4.5 grams of isoleucine, and 5 grams of valine per 100 grams of protein supplement (9).
Rice protein has 8 grams of leucine, 4.1 grams of isoleucine, and 5.8 grams of valine per 100 grams of protein supplement (10). As you can see, both brown rice and pea protein powders contain almost identical level sof the BCAAs. Pea protein has a slight edge when it comes to the muscle-building amino acid leucine.
Pea protein has a slight edge on brown rice protein when it comes to its amino acid profile. This is in part due to the methionine level being closer to the standard level than rice with its lysine levels. Brown rice only contains around 3.1% lysine and it should be at around 4.5% to be considered adequate (1.4% off good levels). Pea protein contains approximately 1.9% methionine and needs to hit about 2.5% for adequate levels (-0.6% off good levels).
Both pea and brown rice protein have good BCAA profiles. These are close to whey protein levels. However, they do lag behind most whey protein isolate supplements.
Pea protein has been favorably compared to whey protein for it's effectiveness in improving strength, performance and muscle growth in individuals following weight training programs (11).
Participants in a three-month trial experienced increases in their one-rep maximum, as well as improved performance and increases in muscle size. The study found there was no noticeable difference between the participants who were supplementing with whey protein and the pea protein powders (12).
Brown rice protein isolates have also been shown to improve the performance and strength of athletes engaged in resistance training programs. The results of a study conducted on individuals who were supplemented with brown rice protein powders showed decreases in fat mass, while simultaneously increasing lean body mass. They also increased the size of their skeletal muscle, with improvements in power and strength to levels similar to the levels of the athletes who supplemented with whey protein (13).
These results were confirmed by another eight-week study showing daily doses of 24g whey or brown rice protein powder together with a weight training program ended with similar body composition and performance improvements (14). The success of the pea protein supplementation in improving health and performance is ascribed to the supplement containing high levels of BCAAs which have been shown to play a vital role in the promotion of protein synthesis (15, 16).
The timing and quantity of protein powder supplementation are important factors when using protein shakes. The research indicates when young adults damage their muscles due to exercise participation, protein synthesis is 20% higher when a protein supplement with leucine, proteins, and carbohydrates is taken, compared with a protein supplement without leucine.
Maximum protein synthesis took place when the protein powder formula included 8 to 11.5 g of essential amino acids as well as 2 to 3 g of leucine and it was drunk immediately after exercise (17, 18).
Both pea and rice protein powders typically contain around 25g to 30g of protein per serving. However, the net quantity of protein is not the only determining factor when it comes to the quality of the protein powder. The percentage of protein per serving can vary based on the additional ingredients which are added to enhance the protein shake.
It must be remembered, both the quantity and quality of protein will determine the results with supplementation. Quality of protein means, how high is the protein content as a percentage of the powders weight, the supplement's critical amino acid and BCAA levels. As a loose rule, supplements with higher protein content and good BCAA levels will support athletic and fitness goals.
Pea protein powder is bland-tasting. It mixes well with most liquids and is less gritty than other protein shakes. Not having a chalky texture and its neutral taste makes it stand out compared to other plant based protein powders. It also combines well with additional flavors to make it more palatable.
Rice protein isolates are, unfortunately, a little more distinctive in flavor and consistency. You’ll either love it or hate it. There doesn’t seem to be a middle ground when describing people’s reactions to it. For this reason pea protein has a slight edge when it comes to both taste and texture.
Due to their complementary amino acid profiles, pea and rice protein isolates make a great blend. Some of the best pea protein powder supplements combine pea with a plant based protein high in methionine such as pea or hemp. The reason for this is to give a superior amino acid profile.
About 90% of plant-based protein powders combine two protein sources as their nine essential amino acids combined offer an improved protein supplement. With rice protein lacking lysine and pea protein having low levels of methionine, the two combine well to offer an optimal amino acid profile with good levels of fiber and iron. A further benefit for those with allergies it both pea and rice protein are hypoallergenic.
If you are looking for an alternative to whey protein, both pea and rice protein provide comparable results. For the best of both worlds, combining pea and rice in a single supplement enhances the amino acid profile and gives a complete protein source. While both rice and pea protein are slightly deficient in key amino acids, we recommend pea protein if you must pick one of the two. The reason for this is it has slightly better leucine levels, a stronger amino acid profile, and a more desirable taste and texture.