Benefits
Muscle protein building after exercise in a plant protein blend
In a small crossover study in resistance-trained adults, 32 g of a blend of pea, brown rice and canola protein raised muscle protein building after leg exercise as much as an equal dose of whey over 4 hours, although blood essential amino acid availability was about 44 percent higher with whey. This tested a blend, so canola protein on its own has not been shown to do this.
Well-balanced amino acid profile with no limiting essential amino acid
Protein quality can be scored by how well a protein supplies the essential amino acids people need. In a feeding study in healthy volunteers, rapeseed protein had no limiting essential amino acid and reached a digestible amino acid score at the top of the scale. Lysine was present, though it was the least digestible of the essential amino acids measured.
Blood amino acid response similar to soy protein
In a crossover study in healthy men, a single 30 g serving of canola protein isolate or canola protein hydrolyzate raised blood amino acids over 8 hours by about as much as the same amount of soy protein, with no difference in nitrogen balance. The hydrolyzate raised amino acids a little sooner, but the total amino acid response was comparable across all three proteins.
High metabolic use of the protein the body absorbs
In a feeding study using labeled protein in healthy volunteers, rapeseed protein was moderately digestible in the small intestine yet lost very little to breakdown, so the share of the absorbed protein the body actually retained and used was high, reported as being as high as that of milk protein. Blood amino acids were not significantly raised after the meal.
Dairy-free and soy-free plant protein source
Canola protein contains no milk protein, lactose or soy, so it is an option for people who avoid those ingredients by allergy, intolerance or choice. The short human feeding studies used it as a stand-alone protein and reported it was well tolerated, though they were small and ran for single servings or a few hours rather than weeks.
Mechanism of action
Napin and cruciferin, the two main rapeseed proteins
Rapeseed protein is built mainly from napin, a small 2S albumin, and cruciferin, a larger 12S storage globulin. Together they supply all of the essential amino acids. The albumin napin resists stomach digestion in laboratory tests, which may slow how quickly some of the protein is broken down and absorbed.
Essential amino acids and the muscle-building signal
Like other complete proteins, canola protein supplies leucine and the other essential amino acids that switch on the mTOR signal behind muscle protein building. In human studies its amino acids reach the blood more slowly and to a lower peak than whey, which supplies essential amino acids faster and at a higher level.
Antinutrients largely removed during protein isolation
Raw rapeseed meal carries antinutritional factors such as glucosinolates, phytate, sinapine and erucic acid that limited its early food use. Physical and chemical processing used to make food-grade protein concentrates and isolates lowers these compounds, which is how modern canola protein became suitable for human foods.
Moderate digestibility offset by low nitrogen loss
In human work, less of rapeseed protein is absorbed in the small intestine than some other plant proteins, but very little of what is absorbed is wasted through deamination. The net result is a high biological value, meaning a large fraction of the protein the body takes up is kept rather than burned off.
Clinical trials
Feeding study using nitrogen-15 labeled rapeseed protein in a mixed meal, with intestinal, blood and urine sampling to measure real ileal digestibility and net postprandial protein utilization. (Bos et al. 2007, J Nutr)
12 healthy volunteers fitted with an intestinal tube (5 at the jejunal and 7 at the ileal level), each given a meal containing 27.3 g of labeled rapeseed protein.
Real ileal digestibility was about 84 percent, lower than some other plant proteins, but deamination loss was very low, so net postprandial protein utilization was about 71 percent and the biological value about 84 percent, reported as being as high as that of milk protein. Blood amino acids were not significantly raised by the meal. A single-meal study in a small group.
Randomized, double-blind crossover study comparing a single 30 g serving of canola protein isolate, canola protein hydrolyzate or soy protein isolate in a drink, with 8-hour blood sampling and 24-hour urine collection. (Fleddermann et al. 2013, Clin Nutr)
28 healthy men, average age about 25 years.
All three proteins significantly raised blood amino acids, and the total 8-hour amino acid response was comparable between the two canola proteins and soy; the hydrolyzate produced an earlier rise. Nitrogen balance did not differ between the three proteins. A companion rat assay found high true digestibility for the canola proteins. A single-serving study.
Feeding study using nitrogen-15 labeled rapeseed or flaxseed protein baked into biscuits, with naso-ileal sampling to measure ileal digestibility, the digestible indispensable amino acid score (DIAAS) and net postprandial protein utilization. (Tessier et al. 2023, Am J Clin Nutr)
19 healthy volunteers; 10 received the labeled rapeseed protein and 9 the flaxseed protein.
Real ileal digestibility of rapeseed protein was about 81 percent, with lysine the least digestible essential amino acid. Despite this moderate digestibility, rapeseed had no limiting essential amino acid, giving a DIAAS of about 1.1, a top-of-scale score, with low deamination and about 70 percent net postprandial protein utilization. Flaxseed scored lower because of lysine.
Randomized, double-blind crossover study of 32 g of protein from whey or from a blend of 39.5 percent pea, 39.5 percent brown rice and 21 percent canola protein, taken after leg resistance exercise, with muscle and blood sampling over 4 hours. Funded by Science in Sport PLC. (van der Heijden et al. 2024, Med Sci Sports Exerc)
10 healthy resistance-trained young adults (8 men, 2 women).
Muscle protein building rose after exercise with no difference between the blend and whey over the 0 to 4 hour period, although blood essential amino acid availability was about 44 percent higher with whey. This was a single-session study of a blend in which canola was about one fifth of the protein, not a study of canola protein alone.