The Scoop On Protein

Protein is a hot topic of debate even in my own household where my teenage son is among the many youth that are interested in bulking up and gaining muscle. But what form of protein is best, and how much protein is necessary, are really complicated questions.

As a nutrition therapist board certified in holistic nutrition, I am a bit skeptical of protein powders and bars as a main source of protein. I certainly take advantage of these from time to time, but even in the absence of evidence to consider them harmful, there is just something unsettling about something so processed.

Many of these protein alternatives are processed using extreme heat, harsh pH conditions, and chemical agents that change the structure of these proteins, and likely their function, as certain properties are lost during the process. This structural change often referred to as denaturation, is not not always a bad thing of course as it is one that our own bodies perform during digestion, and is achieved during cooking as well.

Why is protein so important?

All 3 macronutrients serve important roles in the body. While all three are energy-yielding, carbohydrate and fat are preferred for this purpose. Protein is typically spared for other important structural components of the cells and tissues such as muscle, collagen, hormones, enzymes, antibodies, and transport molecules such as hemoglobin. During pregnancy, proteins serve as the building blocks for fetal growth and development. As you can see, insufficient protein has the ability to negatively impact multiple systems of the body such as metabolism, immune and overall cellular function, and fetal development.

Digestion

When proteins are ingested, they are first mechanically broken down in the mouth by way of chewing. There is no chemical digestion in the mouth like there is with carbohydrates and fat via the enzymes amylase and lipase respectively. It is in the stomach where chemical digestion begins with hydrochloric acid denaturing these proteins so that pepsin is activated and proteolytic enzymes can access these proteins for further degradation to the basic amino acids of which they are comprised. It is these amino acids that will be used to rebuild the specific proteins that the body requires. This can look very different from individual to individual considering an adolescent male, a pregnant female, and someone recovering from surgery all have very different needs.

What is the problem then with proteins that are already denatured?

Undisturbed proteins, in their natural form, are received by the body with their intact components such as vitamins and minerals that act as cofactors and coenzymes, often instrumental in digestion and utilization. Proteins denatured prior to digestion however, are consumed potentially absent of specific functional properties that may be consequential to their biological activity, digestibility, and absorption. At the very least, this may result in reduced nutritional value. While not all denaturation is problematic, and in some cases actually enhances digestibility (certain methods of cooking), it is the more extreme and prolonged processing that should concern us.

Protein powders offer us a good example. Conventional processing includes chemical extraction techniques that use high temperature or alkaline conditions that “could influence the thermal, conformational, and functional properties of protein fractions, reducing their nutritional value and degrading their bioactive compounds.” (1) These processes typically require the use of harmful chemicals and solvents like ethanol and acetone, require longer processing time, and aren’t always cost effective. For this reason they are being replaced with alternative technologies such as enzyme, microwave, and ultrasound-assisted extraction methods that disrupt the cell in order to release its proteins.

While all of these methods are generally reported as producing proteins safe for consumption, there may be unintended consequences that we do not yet fully understand due to limited data. I understand the desire to meet your protein needs, and do so within a sustainable budget, and for vegans and vegetarians this task can be particularly daunting. For a breakdown of the daily recommended protein requirements and some whole food source suggestions, keep reading……

Can we take in too much protein?

Interestingly, there is some discussion and research around the question of how much protein can be absorbed at one meal. This generally applies to higher protein intakes at more than 20-25 grams per meal by those involved in resistance training with the goal of increased muscle mass. While the research is still inconclusive, and many of the studies have limitations, the collective evidence seems to suggest that 1.6 grams per kilogram of body weight is the standard for maximized muscle mass. (2) That said, another review of the literature proposes a target intake of 0.4 grams per kilogram of body weight across 4 meals per day.

Perhaps even more interesting, is the consideration of fast-acting proteins (whey) versus slow-acting proteins (eggs). Certain studies indicate that some of the amino acids of fast-acting proteins may actually be wasted via oxidation or used for energy rather than be used for muscle building, especially at higher intakes. Furthermore, such studies suggest enhanced absorption of slow-acting proteins. With more research needed, this might build the case for whole food based proteins. (2) Regardless, there is currently not enough research to indicate any real difference between the two as far as muscle mass accumulation is concerned.

Some studies suggest increased risk of kidney stress, including kidney stones, altered pH, and increased glomerular filtration rate, with high protein consumption. However, it remains uncertain whether specific renal changes have long-term implications on healthy individuals without existing kidney dysfunction or predisposed to developing kidney disease. (7 ) Either way, the increase in muscle mass gained from higher protein appears to be minimal, and excess protein can be converted to glucose via a process called gluconeogenesis. This means that if not needed immediately for muscle building or energy, protein will be stored as glycogen and fat. (8)

Protein Requirements

The Recommended Dietary Allowance (RDA) set forth by the Food and Nutrition Board, provides a general recommendation for the average healthy adult of 0.8 grams of protein per kilogram of body weight per day. Another way to think about this intake is roughly 0.36 grams per pound of body weight. So for a 125lb female this equates to roughly 45 grams.

However, the requirements for protein vary greatly depending on many factors. Weight, age, sex, and activity level all influence the body’s need for this macronutrient. Additionally, there are certain conditions that may require increased protein such as pregnancy, adolescence, recovery from injury, cancer, and athletic training.

This RDA is also “derived as a minimum amount to maintain nitrogen balance” and is not optimised for physical activity level.” (11) It should also be assumed that the protein being utilized is considered complete, containing all 9 essential amino acids. In general, animal sources of protein are usually complete, while plant sources are incomplete and should be combined with complimentary sources to form a complete essential amino acid profile. Beans and rice is an example of protein combining.

Highlight on protein during pregnancy

In Real Food for Pregnancy, one of my favorite books on prenatal nutrition, author Lily Nichols highlights research that suggests protein intake of 1.22 grams/kilogram of body weight during early pregnancy, and closer to 1.52 grams/kilogram of body weight in late pregnancy (9). This is significantly more than has been traditionally recommended. Other estimates generalize an additional 25 grams per day, especially in the second and third trimesters. As mentioned above, overconsumption of protein is rarely a concern, and is much more relevant among bodybuilders. On the other hand, underconsumption of protein is associated with an increased risk of low birth rate as well as future disease development by the baby. ( 10)

It is important to consider bioavailability. Certain amino acids such as glycine demonstrate higher demand in later pregnancy. (12) This one is best sourced from animal-based foods. In general, choose whole food sources of protein including a mix of plant and animal sources. I don’t usually recommend plant sources alone given their reduced bioavailability and isolated protein sources often lack the accompanying vitamins and minerals that work synergistically to promote health. For example, grass-fed beef is a great source of iron and is much higher in omega 3s than conventionally raised beef, and organic dairy products are great sources of calcium. These three nutrients are equally as important as the protein these foods contain.

The postpartum period also requires special attention to specific nutrients. Unfortunately, the current prenatal and postpartum guidelines do not seem to be keeping pace with the research. For this reason I strongly encourage expecting mothers to seek the support of a nutritional professional that understands the specific nutritional needs during the prenatal and postpartum periods.

Book a 30 minute free consult with Carla to see if she is the right nutrition professional for you here.

Quality protein sources

Quality is key here. This means opting for organic, non-GMO, pastured, and grown in nutrient-rich soil whenever possible. Below are some of my favorites whole food sources and their protein content in grams.

• Eggs-1 egg=6 grams

• Chicken thighs-3 oz=20 grams

• Hummus-2 Tbsp=3 grams

• Salmon-4 oz=22 grams

• Walnuts-1 oz (approx 1/4 cup)=4 grams

• Almond butter-2 Tbsp=6.5 grams

• Quinoa-1/2 cup cooked=4 grams

• Peanut sauce-2 Tbsp=3 grams

• Lentils-1/2 cup cooked=9 grams

• Cottage cheese (Good Culture brand)-1/2 cup=14 grams

• Ground flax seed-2 Tbsp=6 grams

One day sample menu

Breakfast-Smoothie with 2 tbsp almond butter and 2 hard-boiled eggs=18.5 grams

Lunch-Salad with 1/3 cup canned salmon and 1/4 cup lentils=26 grams

Dinner-3 oz chicken thighs with 1/2 cup cooked quinoa and veggies=24 grams

Protein total=68.5

What to consider when opting for protein powders:

Whey

• Whey is considered one of the more bioavailable forms of protein powders on the market; the most bioavailable form, according to the research, as whey protein isolate (not concentrate)(3)

• Whey is dairy-based so may be problematic for some; might be tolerated if allergy/sensitivity to casein and/or lactose only

• Whey is not a suitable option for those on a plant-based diet

• One pilot study shows equitable gains in athletes among strength, performance and body composition whether supplementing with whey protein or pea protein (4)

  Plant-Based Protein

• These include pea, rice, soy, etc.

• Plant sourced proteins are considered to be less bioavailable, and come in combination formulas since plant sources of protein are incomplete

• Plant sources still appear to contribute to strength, performance, and body composition similarly to animal based proteins such as whey (4)

• Soy can be problematic-its estrogenic effects in the body may not make it suitable for everyone

• Plant-based protein powders can be an important source for people on plant-based diets to reach protein goals

  Collagen

• Collagen is not a complete protein; Consists of short-chain amino acids that contribute to overall protein in a supplemental way

• Collagen is the most important protein produced by the human body; it is mainly formed by the amino acid glycine, proline and hydroxyproline

• Comes from animal and marine sources

• Oral ingestion of collagen molecules are absorbed into human plasma; studies reveal highest bioavailability with enzymatically hydrolyzed forms of collagen (6)

• Also not a suitable option for those on a plant-based diet

  Final thoughts

• Aim to obtain the majority of your daily protein from whole foods sources

• Protein powders and collagen are considered supplements and that means they are not FDA approved

• Supplements can be incredibly beneficial however and highest quality should be sought after; look for third party testing in which a reputable laboratory unaffiliated with the retailer is testing these or Good Manufacturing Practice (GMP) certification

• Remember that even without the presence of research to indicate that these protein alternatives are unsafe or do not have any negative impacts on health, there may be unintended consequences of the processing of these yet to be unveiled

• Look for the most minimally processed, organic, non-GMO brands

• Remember that cooking over high heat can damage proteins too; aim for low and slow cooking methods whenever time allows. Check out my Crockpot Pulled Chicken Chimichurri Tacos recipe here.

References:

1.Franca-Oliveira, G.; Fornari, T.; Hernández-Ledesma, B. A Review on the Extraction and Processing of Natural Source-Derived Proteins through Eco-Innovative Approaches. Processes 2021, 9, 1626. https://doi.org/10.3390/pr9091626

2.Schoenfeld BJ, Aragon AA. How much protein can the body use in a single meal for muscle-building? Implications for daily protein distribution. J Int Soc Sports Nutr. 2018 Feb 27;15:10. doi: 10.1186/s12970-018-0215-1. PMID: 29497353; PMCID: PMC5828430.

3.Hoffman JR, Falvo MJ. Protein - Which is Best? J Sports Sci Med. 2004 Sep 1;3(3):118-30. PMID: 24482589; PMCID: PMC3905294.

4.Banaszek A, Townsend JR, Bender D, Vantrease WC, Marshall AC, Johnson KD. The Effects of Whey vs. Pea Protein on Physical Adaptations Following 8-Weeks of High-Intensity Functional Training (HIFT): A Pilot Study. Sports (Basel). 2019 Jan 4;7(1):12. doi: 10.3390/sports7010012. PMID: 30621129; PMCID: PMC6358922.

5.Khatri M, Naughton RJ, Clifford T, Harper LD, Corr L. The effects of collagen peptide supplementation on body composition, collagen synthesis, and recovery from joint injury and exercise: a systematic review. Amino Acids. 2021 Oct;53(10):1493-1506. doi: 10.1007/s00726-021-03072-x. Epub 2021 Sep 7. PMID: 34491424; PMCID: PMC8521576.

6.Aguirre-Cruz G, León-López A, Cruz-Gómez V, Jiménez-Alvarado R, Aguirre-Álvarez G. Collagen Hydrolysates for Skin Protection: Oral Administration and Topical Formulation. Antioxidants (Basel). 2020 Feb 22;9(2):181. doi: 10.3390/antiox9020181. PMID: 32098294; PMCID: PMC7070905.

7. Juraschek SP, Appel LJ, Anderson CA, Miller ER 3rd. Effect of a high-protein diet on kidney function in healthy adults: results from the OmniHeart trial. Am J Kidney Dis. 2013 Apr;61(4):547-54. doi: 10.1053/j.ajkd.2012.10.017. Epub 2012 Dec 4. PMID: 23219108; PMCID: PMC3602135.

8.Pesta, D.H., Samuel, V.T. A high-protein diet for reducing body fat: mechanisms and possible caveats. Nutr Metab (Lond) 11, 53 (2014). https://doi.org/10.1186/1743-7075-11-53

9. Nichols, Lily. Real Food For Pregnancy. USA, Lily Nichols, 2018.

10. Yang J, Chang Q, Tian X, Zhang B, Zeng L, Yan H, Dang S, Li YH. Dietary protein intake during pregnancy and birth weight among Chinese pregnant women with low intake of protein. Nutr Metab (Lond). 2022 Jul 5;19(1):43. doi: 10.1186/s12986-022-00678-0. PMID: 35790993; PMCID: PMC9254546.

11. Lonnie M, Hooker E, Brunstrom JM, Corfe BM, Green MA, Watson AW, Williams EA, Stevenson EJ, Penson S, Johnstone AM. Protein for Life: Review of Optimal Protein Intake, Sustainable Dietary Sources and the Effect on Appetite in Ageing Adults. Nutrients. 2018 Mar 16;10(3):360. doi: 10.3390/nu10030360. PMID: 29547523; PMCID: PMC5872778.

12. Rasmussen BF, Ennis MA, Dyer RA, Lim K, Elango R. Glycine, a Dispensable Amino Acid, Is Conditionally Indispensable in Late Stages of Human Pregnancy. J Nutr. 2021 Feb 1;151(2):361-369. doi: 10.1093/jn/nxaa263. PMID: 32939556; PMCID: PMC7850138.