Marc S. Schneider, M.D.
Protein In Our Diets | A Summary
- The recommended daily allowance of protein has increased
- Athletes have a significantly higher requirement for protein
- Whey protein supplementation provides significant health benefits
- Proteins high in BCAA and EAA benefit muscle synthesis
- Excess animal protein has health risks
- Inadequate protein has health risks
An Introduction to Protein Consumption
What is the best protein for you to consume? Is organic protein better and does it improve lifespan? Is a vegan diet required to improve my health? The movie “What the Health” has certainly raised the awareness that perhaps the average North American diet, one based so highly on animal protein, may have certain health risks. But the science is not as clear-cut as advocates on both sides like to argue.
Is there an ideal protein source out there that will help me achieve my goals, be enjoyable to consume, and help me shape my body the way I want to? The question is much more complex than it seems, and it is multifactorial. To answer this question, we must take numerous issues into consideration. So let’s try and break down the tough question; what is the best protein? After we take everything into consideration and start looking at your goals, you will start to be able to make better decisions about your health and achieving your goals.
How Much Protein Should You Eat?
Recommended Daily Allowance for Protein (RDA)
Before we can discuss what is the best protein, we must tackle how much protein you should actually be consuming in your diet. For years, the recommended daily allowance for protein as advanced by the National Institutes of Health (NIH) has been 56 grams for adult men (all ages), and 46 grams for adult women (all ages).1 The NIH recommends even less than this for those at the ends of the age spectrum: the children and the aged. This has been the NIH’s recommendation for years, and it has driven the basic premise that the diet should consist of about one-third protein.
But does this recommendation, which has influenced the average physician’s philosophy, as well as the food industry’s, reflect what numerous different scientific health studies have shown? Moreover, what do these recommendations even mean?
The NIH reached this 56 grams of protein (for men) calculation based on some simple math. From a science standpoint, the RDA for protein for an average male or female equates to eating approximately 0.8 grams of protein per kilogram of body weight. The NIH says that the average American male is 70 kilograms or 154 pounds. This may have been true in the 1950’s, but it is not true today. Regardless, 0.8 multiplied by the 70 kilogram body weight equates to… you guessed it… 56 grams of protein.
Shortcomings of the Standard RDA
Besides the fact that today’s average American man is not 154 pounds, these recommendations also do not take into consideration the significant differences in energy needs that each individual has based on their daily physical activity, stress, health, or diet. The NIH recommendations also do not differentiate between the different types of protein consumed, nor do they reflect the numerous studies that show health and performance benefits with certain types of protein supplementation.
Remember, there is a difference between protein consumption (the normal meal that you eat) and protein supplementation (additional protein you consume, usually in a powder form).
Hence, the NIH has never come out and stated what is the best protein. They have never guided as to whether one protein type was more beneficial than another, whether one or the other was potentially more harmful, and whether changing your protein intake would affect your body and ultimately your health.
Fortunately, there are scientific studies that do show that different quantities and different amounts can affect your health. Let’s dive into some of those studies based on age and activity level.
Sidenote: 56 grams of protein is about the equivalent of eating 9 ounces of chicken, or two chicken breast halves, meaning the right or left side of the whole chicken breast. One chicken breast is actually the right breast and the left breast, and each half typically ranges from 3 – 4.5 ounces. Similarly, 56 grams of protein is the equivalent of eating two average sized burgers (6 ounces each). And that can come from anywhere on the cow ☺. Now onto those studies!
Protein RDA’s for Athletes
Outside of the NIH, the recommendation by nutrition professionals on the quantities for protein consumption has changed. It has been recommended for the last several decades that athletes consume significantly greater quantities of protein. In fact, the International Society of Sports Nutrition recommends that athletes eat 1.4 – 2 grams of protein per kilogram of body weight daily.2 For a 180 pound athlete, this would be about 160 grams of protein per day or the equivalent of 28 ounces of chicken… 7 large chicken breast halves per day.
Moreover, some data suggests that athletes should consume even more than that. Dr. Jay Hoffman from the Institute of Exercise Physiology and Wellness at University of Central Florida showed that many very high-intensity athletes need more than 2.0 grams of protein per day to maintain their normal body weight.3 Of course, that would be to just maintain normal body weight. If a high-intensity athlete were to try and gain additional lean muscle mass, they would require very high amounts of protein per day to meet their goals.
A bit off topic but important for athletes to understand:
Supplementation with branched-chain amino acids (BCAAs) such as leucine, isoluecine, valine, or metabolites of leucine such as β-hydroxy-β-methylbutyrate (HMB), has been shown to be superior to consumption of dietary amino acids for mTOR activation and muscle protein synthesis. Thus, consuming products such as BCAA’s, New Zealand Whey Protein, or MPO will increase athletic gains and recovery far better than consuming just a chicken breast.
(Atherton et al., 2010; Pimentel et al., 2011; Churchward-Venne et al., 2012; Salles et al., 2013).
Protein RDA’s for Older Adults
So high-intensity athletes require a whole bunch of protein to compete at optimal levels. How much protein should older adults consume then? For years, it was thought that older adults required lower quantities of daily protein intake compared to younger adults. As one ages, you start to lose about 1% of your lean muscle mass each year. Taking this into account, the presumption has been that this meant that the amount of protein required decreased as you got older.
Aging and protein intake is a very complex issue though. On the one hand, caloric restriction diets, such as the intermittent fasting diet, are associated with improved lifespan based on scientific studies.4. Research has shown that individuals who live the longest have notably lower levels of IGF-1, which is also seen from the intermittent fasting diet, and have a lower body mass. While intermittent fasting may decrease IGF-1, studies indicate high protein diets increase IGF-1.
Taking this all into account, scientists have considered the association between low protein intake, low IGF-1, and longevity. Meaning, do those that live longer just happen to take in less protein and have lower IGF-1 levels, or is the low protein intake causing them to live longer?
Physicians know that when an older individual gets sick, they require significantly higher amounts of protein in order to fight off the disease and get healthy. Freeman showed in 2017, that higher than RDA protein consumption (as high as 1.3gm/kg) in older adults resulted in improved physical task performance.5 Moreover, physicians have also noted that lower muscle mass has a direct correlation with frailty, which can lead to difficulty in walking and taking care of yourself.
Yet, in the journal “Cell Metabolism,” Longo showed conflicting results of the effect of protein on two different adult age groups. In adults ranging in age from 50-65, higher protein intake resulted in higher death rates, as well as the higher risk for diabetes and cancer. However, this was only true for those eating large quantities of animal protein, but not for those eating large quantities of vegetable protein. For those over age 65, large amounts of protein consumption were associated with lower death rates and lower cancer risks.6
In another study, Luigi Fontana found that decreasing protein consumption, not caloric intake, lead to lower IGF-1 levels in humans, and this, in turn, may decrease cancer risks and improve longevity.7
So what is this all saying for protein consumption for middle-aged and older adults? Is lower protein intake and lower muscle mass necessary to live longer?
We know that you need more protein to prevent frailty. Obviously, you need more protein when combating an illness. Increasing IGF-1 pharmacologically increases and enhances lifespan in multiple species and mammals. IGF-1 levels directly correlate to muscle mass, and in fact humans require adequate IGF-1 levels to add muscle.8
Unfortunately, the picture is not entirely clear. Adam Sharples tried to tackle these questions and showed the very complex interconnection between muscle mass, longevity, mTOR, IGF-1, and Sirtuins. There seems for the moment to be a conflicting paradigm. On the one hand, as the body ages, it wants to decrease its muscle mass. On the other hand, maintaining muscle mass aids in the function of life. As Sharples concluded, “the future paradigm we should be addressing would, therefore, be the trade-off between maintenance of muscle mass vs. longevity, potentially at the expense of age-related diseases.”9
So what does this mean for you the aging individual? We cannot answer that for you right now based on the science. It seems for now that like everything in life, the amount of protein you consume will be a give a take relationship.
Protein & Nitrogen Balance… Be Positive & Stay Anabolic
We evaluate how the body uses protein by measuring the amount of nitrogen the body either uses or how much it eliminates. When we consume more nitrogen than our body expels, we are in a positive nitrogen balance. Conversely, when we expel more than we consume we are in a negative nitrogen balance. As a rule of thumb, humans want to be in a state of equilibrium or in a positive state. Athletes need to have a positive nitrogen balance.
How can an athlete tell if they are consuming adequate amounts of protein and if they are in positive nitrogen balance? Athletes have huge energy expenditures, and the food and protein they consume fuels the muscles and rebuilds those muscles after intense exercise. If athletes do not consume adequate protein (the muscle building block), their bodies will start to consume its own muscles as a way of producing the amino acids the body needs for daily maintenance. Thus, with inadequate protein intake, the athlete will lose muscle mass and weight. Scientists describe this as being in a catabolic state, which is the opposite of the anabolic state everyone always hears about.
Rating Protein Value | What Is The Best Protein?
Though the scientific community has yet to agree on the amount of protein humans need to consume, we now have a rough idea of how much protein we require daily based on age and goals. Believe it or not though, different types of protein have different effects on your body. Protein is made up of amino acids, and different proteins have different quantities of amino acids. Scientists consider animal protein a complete protein, meaning that it has all 20 dietary amino acids; the ones that you need. Most vegetable proteins are not complete and they are missing certain amino acids. Science can actually measure how your body utilizes a protein using several different techniques to evaluate the quality of the protein.
The protein efficiency ratio, biological value, net protein utilization, and protein digestibility corrected amino acid score are all measures of how well your body uses protein for all its chemical reactions and normal metabolism. For simplicity sake, let’s just discuss biological value aka bioavailability. We often use this scale to answer what is the best protein, but it, of course, does not take all of the factors into account.
The biologic value (BV) of a protein measures how much of the protein is used by your body to form new tissues, and the highest biologic value found in all naturally occurring foods is found in egg, which has a BV of 100. Whole cow milk has a higher BV at 91 than either beef, which is measured at 80, or poultry and fish, which both rank slightly lower. Vegetable proteins measure in the 50’s to 60’s except for soy, which at 74 has a higher BV than Casein.
Whey protein, on the other hand, is a superfood when its biologic value is compared to all other food types. The BV of whey protein concentrate is slightly higher than an egg and is typically measured at around 104. Whey protein isolate however blows all other food types away with a BV measuring 140-159. This means that whey, and specifically whey isolate, provides more usable amino acids for growth than all other proteins.
Please refer to the handy charts found here for more information regarding the rates of protein absorption, as well as the bioavailability of numerous foods. This chart will help you better understand what is the best protein.
Understanding Protein Types | What Is The Best Protein?
We can basically categorize protein as either those that we would eat as a normal everyday meal (food) or those that humans create through processing in order to produce an enhanced powdered supplement.
Food protein is either animal based or plant-based. There are proponents of both, and both have their detractors.
Animal protein advocates point to the higher biologic values of these protein sources as well as to their enjoyment in eating it. High protein, low carbohydrate diets have clearly been shown to help with body fat loss.10. In addition, animal protein is high in B12, Vitamin D (fish, eggs, and dairy), Omega-3 (fatty fish, grass-fed beef and poultry), as well as zinc and heme-iron, which is necessary for red blood cells.
The potential downside of eating large quantities of animal protein is that it has higher saturated fats, and studies have implicated these fats as the causative factor in certain diseases. They also have higher amounts of the amino acid methionine that correlates with high homocysteine levels. Elevated homocysteine levels are directly correlated with cardiovascular disease and blood clots.11
Vegetable protein supporters point out the benefits of a diet that is low in saturated fats and high in essential polyunsaturated fats. These vegetable protein sources also tend to be low in methionine. Vegetarians tend to have a lower risk of heart disease, type 2 diabetes, and they tend to be leaner. However, vegetable protein diets alone may be deficient in certain amino acids unless carefully chosen, and they may not provide adequate support for skeletal muscle growth alone.
Protein Supplements | What Is The Best Protein?
Protein powder supplements provide two benefits: they offer a quick and convenient alternative for those wishing to increase their daily protein intake without having to consume huge quantities of food, and, if properly formulated, they may enhance the quality of the protein consumed for muscle growth.
There are numerous different protein powder types, and it is important to understand that they are not all created equal. Some provide certain benefits that others do not.
Manufacturers often blend different protein powders together to improve the nutritional profile of the powder.
However, sometimes manufacturers design the blends to lessen their costs, or for marketing purposes. Let the buyer beware!
Just for emphasis I’ll reiterate the fact that all protein is not created equal.
- Whey Protein Isolate (WPI)
WPI has the highest BV of all known protein types. It has the highest BCAA content of all protein sources, and the body requires BCAA’s for mTOR activation and muscle growth. To create WPI, whey protein concentrate is purified by removing the fat and the lactose, a complex sugar that many people have trouble digesting. The purification process of making isolate also removes several other biologically active and beneficial proteins that promote health though. WPI is very quickly absorbed by the digestive system (60-90 minutes).
- Whey Protein Concentrate (WPC)
Milk contains two protein types in an 80:20 ratio – Casein and Whey. Whey concentrate is thus the concentrated powdered portion once the casein has been eliminated. WPC has many biologically active proteins that support muscle growth, immune function, and iron levels in blood cells. It does contain lactose, so many manufacturers also put beneficial digestive enzymes in their powders to help with digestion. WPC takes slightly longer to digest (2-3 hours) than does WPI.
Whey protein has been shown to have several health effects such as improving muscle strength and lean body mass, decreasing oxidative stress, improving wound healing, improving glucose metabolism, and lowering blood pressure.
- Whey Peptides
Whey peptides are the WPI protein molecules that are broken down into smaller complex amino acids. The process of muscle growth uses the amino acids, but the proteins are not biologically active. The most recent sports nutrition studies do not support an athletic advantage using peptides over WPI.
- Milk Protein Concentrate
MPC is made from skim milk and contains a concentrated form of casein and whey, as well as lactose and fats, in a powder. Thus, MPC is typically about 80 percent casein and 20 percent whey. A variety of dairy-based products that allow whipping and foaming often use MPC.
- Milk Protein Isolate (WPI)
MPI has a similar protein profile as MPC, except that it has the lactose removed, which will improve digestion for many individuals.
Casein is one of the first protein powders made (1950’s), and its digestion profile is very slow: taking 6-8 hours. For some athletes, they like this characteristic, and take their casein at night before bed. Sort of like having that glass of milk at bedtime.
- Soy Protein
Soy is a complete protein and it has a very high consumption rate amongst vegetarians and in Asia. It also has a high concentration of BCAA’s, as well as having a high concentration of isoflavones and other phytoestrogens. Isoflavones have been found to be beneficial to the cardiovascular system and lower LDL cholesterol. The phytoestrogens found in soy may decrease the risk of breast cancer in women, and they lower the incidence of postmenopausal symptoms. In fact, in Japan where soy consumption is high, postmenopausal symptoms are rare. Soy has however had a negative connotation amongst athletes because of the phytoestrogen content. In the US, almost all soy is genetically modified.
- Vegetable Protein Blends
Vegetable protein powder blends use a variety of different vegetable sources to balance their amino acid profile, as well as to provide a complete protein profile. Typically, blends will combine legume (bean), soy, chia, quinoa, and nut flours. These will normally provide higher quantities of carbohydrate and fats with their protein.
Colostrum is the nutrient dense “pre-milk” liquid secreted by the breast after birth. Its use by strength/power athletes as an ergogenic aid has become common though scientific study results are not entirely conclusive. Some show a benefit, and others do not. Brinkworth saw no significant differences in strength following 8-weeks of training and supplementation in both trained and untrained subjects.12 However, Hofman found that following 8-weeks of colostrum supplementation, significant improvements in sprint performance were seen in elite hockey players.13
Collagen hydrolysate is the isolated, purified protein coming from a variety of sources. Several studies have shown the benefit of collagen powder supplementation with joint pain/arthritis as well as improvements in the quality of aging skin.
Albumin is the most common protein found in the blood and is used to help the body maintain growth and repair tissues. This protein is given to patients with certain severe medical diseases, though in a review of the recent literature, there are no studies supporting its use as a general supplement.
So What Is The Best Protein?
Clearly, answering the question what is the best protein is a much deeper question than it seems. First, it depends on what your goals and needs are: overall health, athletic development, enjoyment. Second, we know that there are pros and cons to the protein issue on both sides of the spectrum. Only consuming animal protein will have certain advantages, but certainly may promote several disease states. Only consuming vegetable protein, similarly, may improve certain health states, but may lead to vitamin deficiency and anemia at one extreme, and may not support strong muscle protein synthesis.
As a previous, two-year strict vegetarian, my personal approach is now one of moderation. I try and keep my daily protein intake up around 1 – 1.3gm/kg. During my pure vegetarian phase, I still consumed whey daily. Resistance exercise and training are important to me and I could not attain the gains I wanted without it.
Today, I limit my red meat consumption significantly… perhaps a few times a month and I make every effort to make sure it is grass fed. My wife becomes anemic without it. Many days I eat only plant protein, while on other days, one of my meals will consist of wild (not farmed) fatty fish (halibut, tuna, salmon), and the others will include plant protein.
I also consume at least two servings of whey protein (New Zealand Whey Protein) daily for several reasons. First, the formulation includes grass-fed, in-pasture, WPI and Native WPC to take advantage of its muscle synthesizing effects. Second, its ingredients help to support the immune system. Thirdly, whey protein also helps to reduce our muscles’ recovery time by directly stimulation muscle protein synthesis.
Your diet should reflect how you want to improve your health and improve the quality of your life. Each one of us has a choice… this life is yours to decide.
References | What Is The Best Protein
1. National Institutes of Health Dietary Reference Link
2. Ralf Jäger, Chad M. Kerksick, Bill I. Campbell, Paul J. Cribb, Shawn D. Wells, Tim M. Skwiat, Martin Purpura, Tim N. Ziegenfuss, Arny A. Ferrando, Shawn M. Arent, Abbie E. Smith-Ryan, Jeffrey R. Stout, Paul J. Arciero, Michael J. Ormsbee, Lem W. Taylor, Colin D. Wilborn, Doug S. Kalman, Richard B. Kreider, Darryn S. Willoughby, Jay R. Hoffman, Jamie L. Krzykowski and Jose Antonio. International Society of Sports Nutrition Position Stand: protein and exercise Journal of the International Society of Sports Nutrition 2017 14:20 Link
3. Protein Supplementation and Athlete Performance. Jay R. Hoffman, Ph.D. Link
4. Aging, adiposity, and calorie restriction Fontana L., Klein S. JAMA, 297 (2007), pp. 986–994 Link
5. The relationship between habitual dietary protein and intake and dual task performance in sedentary, recreationally active, and masters athlete older adults. Freeman, WL., 2017, Health, Human Performance and Recreation Undergraduate Honors Thesis. 51 Link
6. Low Protein Intake Is Associated with a Major Reduction in IGF-1, Cancer, and Overall Mortality in the 65 and Younger but Not Older Population. Morgan E. Levine, Jorge A. Suarez, Sebastian Brandhorst, Priya Balasubramanian, Chia-Wei Cheng, Federica Madia, Luigi Fontana, Mario G. Mirisola, Jaime Guevara-Aguirre, Junxiang Wan, Giuseppe Passarino, Brian K. Kennedy, Min Wei, Pinchas Cohen, Eileen M. Crimmins, Valter D. Longo. Cell Metabolism V19-3 407-417. 2014 Link
7. Long-term effects of calorie or protein restriction on serum IGF-1 and IGFBP-3 concentration in humans. L. Fontana, E.P. Weiss, D.T. Villareal, S. Klein, J.O. Holloszy Aging Cell, 7 (2008), pp. 681–687 Link
8. Resistance training, and IGF involvement in the maintenance of muscle mass during the aging process. Adamo ML, Farrar RP Ageing Res. Rev. 5, 310–331 (2006). Link
9. Longevity and skeletal muscle mass: the role of IGF signaling, the sirtuins, dietary restriction, and protein intake. Sharples AP., Hughes, DC., Deane CS., Saini AS., Selman C., Stewart CE., Aging Cell 10 April, 2015 Link
10. High-protein weight-loss diets: are they safe and do they work? A review of the experimental and epidemiologic data.Eisenstein J, Roberts SB, Dallal G, Saltzman E Nutr Rev. 2002 Jul; 60(7 Pt 1):189-200. Link
11. Toxity of Methionine in Humans. Garlick, PJ., The Journal of Nutrition, June 2006 Link
12. Bovine colostrum supplementation does not affect plasma buffer capacity or haemoglobin content in elite female rowers.Brinkworth GD, Buckley JD Eur J Appl Physiol. 2004 Mar; 91(2-3):353-6. Link
13. The effect of bovine colostrum supplementation on exercise performance in elite field hockey players.Hofman Z, Smeets R, Verlaan G, Lugt Rv, Verstappen PA Int J Sport Nutr Exerc Metab. 2002 Dec; 12(4):461-9. Link