Does Protein Quality Make a Difference?
Ask a health consultant if synthetic vitamins are just as good as natural, food-based versions. You might hear that the food industry and government are conspiring to poison us. Synthetic versions work, but research shows some natural sources do indeed work better. Why? Phytonutrients and other synergistic agents found in food sources often add absorbability and functional value. Evolution can be crafty like that in the kitchen. The concepts of bioavailability and interaction are foundational throughout biology -- there is an optimal recipe and context for every life process. That doesn't mean we'll hit it every time, but knowing the gold standard is what science is all about. The higher we climb the range between "good enough" and perfect, the more likely you are to snag a longer, healthier life.
Protein is no different. You're a sophisticated reader -- let's see what perfect looks like in terms of boosting muscle-building and performance skills with some deft amino acid manipulation. But, first, there are substantial quality implications when linking protein to cellular communication and well-being. Protein is critical for... everything! Consider how many health maladies are linked to protein signaling and the fact that amino acids are dubbed the building blocks of life. As a matter of fact, one of the highest goals of quality ranking is to ensure healthy pregnancy and post-natal development.
Methods of Assessing Quality
When protein powder began to dominate the supplement industry, it was common to measure quality in terms of Biological Value (BV). You can consider BV a good starting point. It was created to help discern how much of the protein consumed actually yielded deliverable amino acids to cells. The Protein Digestibility-Corrected Amino Acid Scale (PDCAAS) took over as the preferred tool by factoring in actual needs for essential amino acids -- those your body can't produce. As progress rolled on, yet another standard was generated to tie up loose ends. Currently there is a movement to make the Digestible Indispensable Amino Acid Score (DIAAS) the unified standard for reasons like adding amino acids back into the score that algorithmically discounted the effect of surplus amino acids. The DIAAS also corrects for a likely overestimation of how much fecal amino content is returned to the body. Yeah, so there's that -- poo talk always elevates a conversation.
So, that was fun, right? Everyone loves biochemistry. Kidding, but it is our foundation. Moving onto the good stuff...
Recall that I mentioned genetics and training stimulus join nutrition as primary factors in muscular development and strength. This is the place I get to say that amino acids -- derived from protein -- are the precursors to muscle tissue adaptation. When it comes to the nutrition side of this three-legged stool, quantity and quality carry similar weight. One without the other won't take you very far. When discussing quantity, I showed that while the RDA of 0.8 grams of protein ingested per kilogram of body weight provides the basement-level minimum, most science agencies now recommend more than twice that amount, up to 2.0 grams per kilogram of body weight. Assuming we have quantity covered; can the source and timing of protein yield nuanced results?
Based on factors including testable quality (PDCAAS or DIAAS), which factors specific amino acid content, the answer is yes. Other variables include the context of the meal (fasting, post-workout, etc.), source, and whether the source is in liquid or solid state, which influences speed of digestion. I'll address digestion further when I turn the series toward meal planning, but let's talk amino acid specificity.
One example that comes to mind to illustrate more bang for your buck is leucine, one of the three branched-chain amino acids that drive protein synthesis. Leucine, however, is emerging as the workhorse, with some studies showing optimal protein synthesis in meals that include 2.5 g of leucine as part of about 20 grams of protein. Branched-chain amino acids, essential amino acids, and even leucine can be supplemented individually to fortify meals or to elevate blood nitrogen levels between meals.
In light of the desire to maximize protein synthesis, meal timing and protein sources need to be examined in context. Context, context, context -- it's the first grid through which to interpret research.
Just Tell Me What to Eat!
When considering timing, breakfast is a key place for protein because of the night fast. Plasma amino acids are low. Studies show significant metabolic and satiety benefits that can last all day -- profound for weight loss as well as anabolism. Similar metabolic and anabolic considerations must bookend training sessions. I mentioned previously that the famed "anabolic window," once thought to be a mere 10 to 30 minutes post-workout, is now being considered obsolete. A mounting number of studies show as long as you eat protein within a couple hours, complete recovery and long-term gains are probable. But let's consider that a safety net. After taxing muscle tissue and body systems maximally, stimulating cortisol and creating the environment for recovery, wouldn't immediate nutrition be helpful? Of course it would. When preparing for that workout session, would buffering that training environment with a pre-load of amino acids be helpful? Yes. That hasn't been in question until recently as studies show aggregate results instead of focusing on acute, workout-by-workout blood and tissue markers. One is good enough; one gets us closer to perfect.
As we turn toward meal timing and formatting, liquid-versus-solid comes into play. The reason whole-food sources, like chicken, fish, and beef, rate lower on utilization scales, is primarily because less amino content is absorbed from animal muscle fiber. Ironically, it was once thought that a rapid-digesting, high-biological value isolate like whey might act like a high-glycemic index carb and therefore be superior. And it is great for speedy uptake. But isolates fell out of favor as heavier molecular weight proteins showed a longer span of nitrogen elevation because of slower digestion. Currently, the tables have turned again -- somewhat -- as the faster-acting isolates are showing an ability to reduce hunger sooner because of rapid impact. You can see how timing and source can be used strategically for your particular needs, and why context is king. We'll cover that next!