When it comes to one's health and performance, protein plays a crucial role. While acknowledging the importance of other macronutrients, it is essential to understand protein requirements, whether you aspire to be a bodybuilder, a top athlete, or simply want to age gracefully with minimal decline.
In the past, the significance of protein may have been a matter of debate, but today, it is widely recognized by nutrition-savvy individuals. However, amidst growing concerns about the environmental and ethical impacts of animal-based foods, there is an increasing interest in exploring the role of plant-based protein powders. In this article, we will delve into the subject, specifically focusing on whether plant-based protein powders can effectively meet our protein needs.
The Three Primary Functions of Dietary Protein
Within the context of this articledietary protein serves three main purposes:
- Maximizing muscle protein synthesis
- Preventing muscle protein breakdown
- Providing the necessary building blocks for muscle repair and growth
These functions contribute to reducing muscle loss during rest and promoting muscle mass gains following resistance training, regardless of age. Furthermore, adequate protein intake is associated with increased strength, athleticism, cardiovascular health, blood glucose management, and bone health. Therefore, ensuring that one meets their protein needs is essential for overall well-being. Fortunately, making protein recommendations to achieve these goals is relatively straightforward.
Determining Daily Protein Requirements
- Adequate daily protein consumption is crucial. While recommendations may vary, intakes ranging from 1.6 to 2.2 grams of protein per kilogram of body weight are generally considered suitable for promoting muscle mass gains over time when in a calorie surplus. In a calorie deficit, commonly recommended figures range from 2.3 to 3.1 grams per kilogram of lean body mass or 1.8 to 2.7 grams per kilogram of total body mass. However, caution should be exercised when using these recommendations based on total body mass, as higher body fat can skew the actual protein requirement.
To clarify, an individual with a lean body mass of 80 kilograms will require the same amount of protein, regardless of whether their total weight is 90 kilograms or 130 kilograms. Therefore, when using these numbers in practice, it is advisable to opt for the lower end of the hypertrophy recommendations for individuals who may have some excess weight to lose. For those aiming for fat loss, it is recommended to use lean body mass-based recommendations. While this approach may seem somewhat subjective and open to interpretation, it exemplifies the versatility of nutrition as an applied science.
- Protein should be distributed evenly throughout the day. Recent research suggests that muscle protein synthesis (MPS) reaches its maximum level within approximately 90 minutes after protein consumption and returns to baseline around 90 minutes later, regardless of the presence of sufficient amino acids in the bloodstream. Interestingly, resistance training seems to extend the duration of MPS activation, which may partly explain its positive impact on muscle mass.
- The quality of protein is crucial, and this aspect becomes particularly relevant when considering plant-based protein powders. Historically, the majority of protein research has focused on animal-based proteins. Studies that investigated MPS and the muscle full effect, mentioned earlier, were conducted using animal-based proteins due to their higher effectiveness in promoting MPS. But what does "protein quality" actually mean?
Understanding Protein Quality
Protein quality measures aim to assign a numeric rating to various protein sources. The two most commonly used measures are the Protein Digestibility Corrected Amino Acid Score (PDCAAS) and the Digestible Indispensable Amino Acid Score (DIAAS). Both serve a similar purpose: evaluating proteins based on their usefulness for human nutrition, considering various factors that influence protein quality. The DIAAS accounts for ileal absorption of amino acids, whereas the PDCAAS does not.
Additionally, the DIAAS compares proteins to a theoretically perfect one, while the PDCAAS compares proteins to egg protein. Other factors that influence protein quality include the comparison of human requirements for each amino acid, the amino acid content of the food, and the presence of anti-nutrients derived from food that may hinder absorption.Regardless of the measure used, plant proteins generally do not perform as well as animal-based proteins, especially when compared to animal-based protein powders like whey (table below adapted from.
Comparison of Protein Digestibility Scores
Interestingly, soy protein isolate stands out as an exception in the table above. A 2018 meta-analysis of long-term studies (lasting six months or longer) found no significant difference in lean body mass accrual when comparing soy to other proteins, including whey.Does this mean that muscle building is impossible with plant protein? It is a bit more complicated than that. Firstly, the studies included in the meta-analysis were generally conducted on small numbers of people, with most participants being untrained.
It is well-known that untrained individuals tend to gain muscle regardless of the dietary intervention, making it challenging to extrapolate their outcomes. Furthermore, the meta-analysis had limitations such as variations in study design, low protein intakes across the board (all below the lower end of the recommended 1.6 grams per kilogram of body weight), and other factors, as acknowledged by the authors. In this article, we will focus on one crucial point discussed by the authors.
In acute studies (typically lasting three hours or less), soy protein has been found to stimulate muscle protein synthesis less effectively than whey. Even when essential amino acids are matched, soy often falls short compared to its milk-derived counterpart. Additionally, concerning elderly men, while a 40-gram dose of soy isolate increased MPS after exercise, a 20-gram dose failed to do so, and neither dose increased MPS at rest. In contrast, whey was effective at stimulating MPS even with a 20-gram dose during rest.
This discrepancy is likely due to the lower leucine content in soy and most other plant-based proteins when compared to animal proteins, particularly whey. Leucine effectively stimulates muscle protein synthesis through the activation of the mTOR pathway. Multiple studies have shown that the MPS response to plant-based protein is equivalent to that of whey or other animal-based proteins only when the leucine content is matched. This suggests that plant-based proteins can effectively support muscle building and maintenance, provided a higher dose or a regular dose with added leucine is consumed.
In a study conducted on older men, 35 grams of wheat protein did not stimulate MPS as effectively as 35 grams of whey did. However, when the wheat protein dose was increased to 60 grams to match the leucine content of whey, it not only matched the MPS response but surpassed it (although the higher protein content in the wheat protein contributes to this effect).Taking this into account, an increasing number of sports nutrition companies have started exploring powders that combine multiple plant protein sources to create amino acid profiles closely resembling whey. The aim is to provide plant-based athletes with an option that surpasses soy protein in terms of effectiveness while remaining aligned with their plant-based principles.
The Evidence on Mixed-Source Plant Protein Powders
Referencing the table mentioned earlier, you may notice that a "limiting amino acid" is listed in the final column. The term is self-explanatory: within each food, the ratio of each amino acid varies. For example, 5 grams of protein from steak and 5 grams from asparagus consist of the same building blocks but differ in composition, affecting the MPS response. Each protein source has an "ideal" ratio of essential amino acids, and dairy proteins come close to this ideal.
However, even dairy proteins have slight deficiencies in one or more amino acids. In many of the proteins listed, as shown by both PDCAAS and DIAAS, this does not have a practical impact. However, in proteins lower down the table, the presence of limiting amino acids becomes more significant. Fortunately, when one protein source lacks a specific amino acid, this can be compensated by another source. This concept has led to a thriving market for plant-based protein powders that combine various protein sources to create complete amino acid profiles.
Studies have supported this approach, showing that a protein blend comprising a 1:1:2 ratio of soy, whey, and casein protein stimulates MPS to the same extent as whey in both young and older individuals. Although this protein blend only includes 25% plant protein, it provides evidence that a protein source containing plant-derived amino acids can be as effective as one derived from animal sources, provided the amino acids complement each other well.
However, it is important to note that this does not prove that 100% plant-derived combined proteins will yield the same effects. At the time of writing, which is September 1st, 2020, there is no experimental evidence supporting this claim. Nevertheless, this is an emerging area of research, and in the 18 to 24 months following the publication of this article, we can anticipate a significant number of studies shedding light on the impact of combining complementary sources like pea and rice.
To conclude, let us revisit the three points raised at the beginning. Consuming an adequate amount of protein, at regular intervals, and of high quality is crucial. When combined with sufficient sleep, well-designed training programs, and a calorie intake appropriate for one's goals, the choice of a specific protein powder becomes relatively minor in the broader context.Considering the meta-analysis mentioned earlier, which found no significant difference over time between soy and whey, at least in untrained individuals, and a well-documented pilot study from 2019 that showed no difference over an eight-week period between pea protein and whey, We predict the following:
Even if future research reveals a slightly lesser MPS response to combined plant-based protein powders compared to whey (although I don't anticipate this outcome), the actual differences in terms of strength, muscle mass, and overall health over the course of months and years will be so minimal that they will be practically insignificant. In the grand scheme of things, the choice between whey and plant-based blends will have little impact, especially when considering the comprehensive lifestyle factors required for optimal results.
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