An adequate protein intake is essential for the body's well-being and performance, because the body uses this nutrient in many cellular functions.
Proteins are nitrogen-containing substances made up of amino acids (AA). Not only the quantity but also the quality of protein in the diet is important for the body's proper functioning. Protein quality depends on the AA profile, among other factors. 20 total AA (TAA) have been identified as necessary for human growth and metabolism. Of the 20 TAAs, nine of them are defined as essential AA (EAAs, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine), and the remaining eleven are considered non-essential AA (NEAAs, alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine and tyrosine). In addition, branched-chain amino acids (BCAA, leucine, isoleucine, and valine) are found within the EAAs.
The NEAAs can be synthesized by the body, while the EAAs must be ingested from the diet. In this sense, proteins can be classified into two groups: high or low biological value, depending on the presence or absence of all the EAAs in their composition. Today, this distinction is usually called animal or vegetable proteins, respectively, because proteins from meat, eggs, and dairy products have higher amounts of EAAs, including leucine, while proteins from legumes, seeds, or nuts have a deficit in some of them.
In the diet, the consumption of a mixture of plant-based proteins (i.e., complementary proteins) is a common strategy to compensate for the fact that individual sources of plant-based proteins are often deficient in one or more EAAs. For example, the combination of rice protein (high in methionine but low in lysine) and pea protein (low in methionine but high in lysine) can produce a pea-rice protein blend with a balanced amino acid profile, free of deficiencies. Therefore, the formulation of a plant-based protein blend represents an opportunity to develop a high-quality protein option.
The present study has as its main objective to evaluate the postprandial bioavailability of EAA from two plant-based protein sources present in a complete powdered meal, where one will have soy protein and the other product with a protein source from a mixture of rice and pea protein.
The secondary objectives of the study are to compare the following kinetic parameters and the metabolic response of the two products with different plant-based protein sources.
* Bioavailability of AAT (AAT-AUC0-240min), AANE (AANE-AUC0-240min), BCAA (BCAA-AUC0-240min) and of each of the EAA individually (EAA-AUC0-240min).
* Time to reach maximum concentration of AAT (AAT-Tmax), AAE (AAE-Tmax), AANE (AANE-Tmax), BCAA (BCAA-Tmax) and of each EAA individually.
* Maximum concentration of AAT (AAT-CMax), AAE (AAE-CMax), AANE (AANE-CMax), BCAA (BCAA-CMax) and of each EAA individually.
* Insulinotropic response: insulin and blood glucose levels.
* Objective hunger and satiety modulation: blood levels of hunger and satiety regulating hormones: glucagon-like peptide-1 (GLP-1), peptide YY (PPY), ghrelin.
* Modulation of hunger and subjective satiety.
* Changes in the expression of genes involved in oxidative and inflammatory metabolism.
During the study there will be 3 visits: a preselection visit (V0), a visit for the first postprandial study (V1) and after one week washing period, a visit for the second postprandial study (V2).
