Nutrition Science

Nutrition research is the underpinning of our programs and outreach. ENC is dedicated to providing accurate and up-to-date information on eggs, nutrition and health. Below is a collection of both ENC-funded research and relevant studies.

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Physiological Impacts of Protein and Effects on Weight Management

ENC likes to provide the opportunity for up and coming investigators to showcase their research, and today’s post comes from a student of Jamie I. Baum, PhD, Assistant Professor of Nutrition at the University of Arkansas. Dallas Johnson is a graduate of the University of Arkansas receiving a B. S. in Biology. He now works as a research associate in Dr. Jamie Baum’s lab conducting projects focusing role of dietary protein on energy metabolism and metabolic health. Dallas has recently been accepted in to medical school and will be starting in the fall of 2015.

lab-scientist-stock-photoMore than one third of Americans are obese, making obesity a very real public health concern (1). Obesity comes with a multitude of health issues including cardiovascular disease, elevated risk of diabetes and metabolic syndrome. While individual situations can vary greatly, increasing protein levels in the diet has been shown to be an effective way to help combat obesity (2).

One of the ways protein can affect daily calorie intake is through its ability to increase satiety. Although high carbohydrate meals can increase satiety acutely, meals higher in protein (20-30% of the total energy provided by the meal) have been shown to have a more prolonged effect on satiety.  According to a study by Westerterp-Plantenga et al., published in the British Journal of Nutrition, this feeling of satiety is attributed to the ability of protein to stimulate the release of glucagon-like peptide-1 (GLP-1). Specifically, GLP-1 mediates the so-called “ileal brake”, an inhibitory feedback mechanism which controls the motility of a meal through the gastrointestinal system, and thus slows gastric emptying (3), thus leading to the feeling of being “full.” Moreover, free amino acids are released into the bloodstream following a high protein meal, which can also enhance the feeling of fullness (4).

In addition to inducing satiety, a high protein diet has also been found to impact the body’s daily energy expenditure. Daily energy expenditure can be broken down into different categories.  Active expenditure is the most variable form and results from physical activity. Resting metabolic ratecomprises around 70% of one’s daily calorie use and doesn’t vary much. One of the variants in resting metabolic rate is the total weight of lean tissue (e.g. muscle) in the body (4). Lean tissue can be increased or maintained by engaging in regular resistance exercise and a consistent intake of protein and calories in daily meals (4).

Protein not only has the potential to affect long-term energy expenditure but can also affect calories burned directly after a meal (diet-induced thermogenesis), even more so than other macronutrients (5). This increase in diet-induced thermogenesis is partly due to an enhanced protein turnover rate.  When the body is flooded with more protein than it can handle, it actively oxidizes and eliminates the excess amino acids. This leads to an increase in thermogenesis and the resultant up-regulation of uncoupled protein-2 (UCP2) in the liver and uncoupled protein-1 (UCP1) in brown adipose tissue, in turn, leads to higher energy expenditure (5).  Protein is also an inefficient source of ATP compared to fat and carbohydrate, requiring several stages of metabolism, including urea synthesis, before becoming available for energy production. According to a recent study, up to forty-two percent of the observed increase in energy expenditure following a high-protein, carbohydrate-free meal can be explained by these additional steps and the increase in gluconeogenesis that follows (4).

The battle against obesity is a very complex, multi-faceted issue that includes hormonal balance, genetic makeup and metabolic processes, but evidence from recent and ongoing studies suggests that protein can play an important role in body weight management.



1. Ogden C. L., Carroll, M. D., Kit, B.K., & Flegal K. M. (2014). Prevalence of childhood and adult obesity in the United States, 2011-2012. Journal of the American Medical Association, 311(8), 806-814.

2. Rodriguez, N., & Garlick, P. (2008). Introduction to protein summit 2007: Exploring the impact of high-quality protein on optimal health. The American Journal of Clinical Nutrition, 87, 1551-3.

3. Marathe CS, Rayner CK, Jones KL, Horowitz M. Effects of GLP-1 and incretin-based therapies on gastrointestinal motor function. Exp Diabetes Res. 2011;2011:279530.

4. Westerterp-Plantenga, M., Lemmens, S., & Westerterp, K. (2012). Dietary protein- its role in satiety energetics, weight loss and health. British Journal of Nutrition, 108, S105-S112.

5. Paddon-Jones, D., Matters, R., Wolfe, R., Astrup, A., & Westerterp-Plantenga, M. (2008). Protein, weight management, and satiety. The American Journal of Clinical Nutrition, 87.

The Link Between Nutrition, Exercise and Muscle

lab-scientist-stock-photoENC likes to provide the opportunity for up and coming investigators to showcase their research, and today’s post comes from a student of Jamie I. Baum, PhD, Assistant Professor of Nutrition at the University of Arkansas. Brianna L. Neumann graduated from Truman State University with a bachelor of science in Exercise Science.  Her undergraduate research experience involved sports nutritional research, which began her desire to continue her education to focus on protein’s metabolic effect in the body.  She currently is a Master’s student at the University of Arkansas in the Department of Food Science, where her research specifically focuses on the impact protein quality and quantity on whole body energy metabolism.

In today’s society, big muscles are associated with weight lifting, men and sports. However, for most people, the benefits of gaining muscle mass include improvement in gross motor skills and a potential decrease in sarcopenia (gradual age-related loss in muscle mass and function). When discussing the building of muscle mass, a term you need to be familiar with is muscle protein synthesis (MPS). In general, in order to gain muscle mass, you need to synthesize more muscle than your body is breaking down. Through extensive research on muscle mass, it is known that an outside stimulus, such as resistance exercise, is required for building muscle. More recently, it has been discovered that nutrition, specifically in the form of protein, also plays a vital role in the physiology of this process5, 6.

Research has shown that consumption of high-quality proteins (e.g. beef; eggs) can stimulate MPS in both young and elderly individuals, following a meal8, and this effect may be attributed particularly to the quality – not just the quantity – of the protein. High-quality proteins tend to be from animal sources and include eggs, poultry, beef and dairy, which are high in essential amino acids (EAA), particularly the branched-chain amino acid leucine. Data show that leucine promotes MPS at a greater rate than that of the other EAA due to leucine’s ability to activate the mammalian target of rapamycin (mTOR), the key regulatory pathway in MPS1, 3.

A recent study clearly demonstrates the relationship between EAA and MPS. Eight individuals were given 10 grams of EAA on two separate occasions and a dose of rapamycin (an inhibitor of mTOR) on one occasion, which led to a 60% increase in MPS following ingestion of EAA.  However, this effect was completely blocked when subjects were treated with rapamycin4. In addition, another study tested 8 healthy, sedentary older adults with diets supplemented by leucine for 2 weeks (4 grams per meal) and found a significant increase in muscle fractional synthesis rate at the end of the treatment period4.  The muscle fractional synthesis rate is the fraction of the proteins that are synthesized in the muscle per unit of time9.

Resistance exercise can also increase MPS and add “bulk,” or increase muscle mass. There are two primary principles of exercise that need to occur in order for someone to successfully add “bulk”: progression and overload. The most important for MPS is overload, defined as placing additional stress on a muscle above normal conditions, and includes exercises such as weight lifting and swimming. Therefore, in order for someone to “bulk up,” they must have an outside stimulus that serves to initiate MPS inside the body. There are various ways to achieve overload such as adding more weight or increasing a swimming distance, and research is still being done regarding how to maximize MPS. A recent study examined the effect of concentric resistance exercise on 8 trained men2 to determine if muscle building signaling enzymes were progressively increased as more sets of resistance activity were performed. The investigators concluded that performing additional sets showed a greater increase in MPS than just a single set of lifts.

Is there an additive effect of protein ingestion and resistance exercise? As stated above, both exercise and nutrition initiate MPS, and ideally, one would have both in order to maximize muscle building within the body. For example, the effect of beef ingestion coupled with resistance exercise was recently tested in 35 middle-aged men who consumed one of four different amounts of beef (0, 57, 113 and 170 grams) prior to resistance exercise (unilateral movements). Results of this study demonstrated that eating 170 grams of beef in addition to exercise significantly elevated MPS when compared to the other groups7.

In summary, MPS is complex and can be influenced by both nutrition and exercise. Both can activate MPS individually, but research shows combining the two is best to promote MPS. Further research is still needed to understand the long-term impact of this combination, as well as the practicality of dietary intake for individuals in order to maintain and increase muscle tissue.


  1. Anthony JC, Yoshizawa F, Anthony TG, Vary TC, Jefferson LS, Kimball SR. Leucine stimulates translation initiation in skeletal muscle of postabsorptive rats via rapamycin sensitive pathway. Journal of Nutrition. 2000; 130(10): 2413-9.
  2. Burd NA. Holwerda AM, Selby KC, West DW, Staples AW, Caine NE, Cashaback JG, Potvin JR, Baker SK, Phillips SM. Resistance exercise volume affects myofibrillar protein synthesis and anabolic signaling molecule phosphorylation in young men. Journal of Physiology. 2010; 588(Pt 16): 3119-30.
  3. Caperson SL, Shelffield-Moore M, Hewlings SJ, Paddon-Jones D. Leucine supplemenatation chronically improves muscle protein synthesis in older adults consuming the RDA for protein.Clinical Nutrition. 2012; 31(4): 512-519.
  4. Dickson JM, Fry CS, Drummond MJ, Gundermann DM, Walker DK, Glynn EL, Timmerman KL, Dhanani S, Volpi E, Rasmussen BB. Mammalian target of rapamycin complex 1 activation is required for the stimulation of human skeletal muscle protein synthesis by essential amino acids.The Journal of Nutrition. 2011; 141(5): 856-62.
  5. Drummond MJ, Rasmussen BB. Leucine-enriched nutrients and the regulation of mammalian target of rapamycin signaling and human skeletal muscle protein synthesis. Current Opinion in Clinical Nutrition and Metabolic Care. 2008; 11(3): 222-6.
  6. Millward DJ, Layman DK, Tomé D, Schaafsma G. Protein quality assessment: impact of expanding understanding of protein and amino acid needs for optimal health. American Journal of Clinical Nutrition. 2008; 87 (5): 1576S-1581S.
  7. Robinson MJ, Burd NA, Breen L, Rerecich T, Yang Y, Hector AJ, Baker SK, Phillips SM. Does-dependent responses of myofibrillar protein synthesis with beef ingestion are enhanced with resistance exercise in middle-aged men. Applied Physiology, Nutrition, and Metabolism. 2013; 38 (2): 120-5.
  8. Symons TB, Sheffield-Moore M, Wolfe RR, Paddon-Jones D. A moderate serving of high quality protein maximally stimulates skeletal muscle protein synthesis in young and elderly subjects.Journal of American Dietetics Association. 2009; 109(9):1582-6.
  9. Wolfe RR. Skeletal muscle protein metabolism and resistance exercise. The Journal of Nutrition. 2006; 136(2): 525S-528S.

What’s New in the World of Diabetes Research?

Amy-Campbell_2Today’s post comes from Amy Campbell, MS, RD, LDN, CDE. Campbell is a nationally-known dietitian, author, blogger and lecturer specializing in nutrition and diabetes management. As a certified diabetes educator, she was a diabetes educator and program manager at Joslin Diabetes Center in Boston, MA for over 19 years. She is a contributing author to Diabetes Self-Management and Walgreens’ Diabetes & You magazines, where she also serves on the editorial board, and writes a weekly blog for the Diabetes Self-Management website. In addition, she co-authored a book entitled 16 Myths of a “Diabetic Diet”, published by the American Diabetes Association, for which she received both the Will Solimene Award of Excellence in Medical Communication and the 2000 National Health Information Award. Campbell is a Health Professional Advisor for the Egg Nutrition Center, serves on the expert panel for US News’ “Best Diets,” is a expert and has been an advisor for Calorie King, America’s leading provider of calorie-centric education tools and programs.

The landscape of diabetes research is constantly changing.  As a certified diabetes educator, I admit that I often have a hard time keeping up with the latest developments that are coming (or that have come) down the pipeline. The race for a diabetes cure is still going full throttle, but in the meantime, researchers are busy looking for other ways to treat a chronic condition that currently affects 29 million Americans and that could potentially affect another 86 million who are at risk for developing type 2 diabetes.

A Bionic Pancreas

It sounds so “new-agey,” but researchers at Boston University and Massachusetts General Hospital have created and are currently testing a bionic pancreas for people with type 1 diabetes. People with type 1 diabetes must inject insulin to survive. Most people with type 1 inject insulin anywhere from 2 to 4 times daily, or use an insulin pump to infuse insulin, and check their blood glucose up to 10 times (or more) every day. Obviously, this is a very labor-intensive disease. The bionic pancreas consists of a tiny sensor that’s inserted underneath the skin. This sensor monitors the level of glucose in the tissue and based on that level, can deliver insulin or glucagon via two automatic pumps.  In one instance, twenty adults wore the bionic pancreas and carried a wireless monitor for five days, doing and eating what they wanted, and following no particular schedule.  In another instance, 32 children wore the pancreas for five days while at a camp for children with type 1 diabetes.  The findings? There were 37 percent fewer interventions for hypoglycemia and more than a twofold reduction in time spent in hypoglycemia. Overall, blood glucose levels were significantly improved, particularly during the overnight hours1. The diabetes community is excited about this new technology, but it’s not yet ready for prime-time. The technology needs refining, and larger-scale clinical trials are necessary to show efficacy and safety before the bionic pancreas is suitable for home use.  Stay tuned!

Good Fat, Bad Fat, White Fat, Brown Fat

Chances are you don’t think too much about the type or color of the fat in your body. Well, maybe it’s time to give your fat a second look! When we think about fat, we generally think in terms of having too much of it and ways that we can reduce the amount. But researchers are looking at fat in a different light; specifically, they’re looking at the color of the fat in the body. White fat, which is the most abundant type of body fat, is found throughout the body, and it cushions and protects internal organs. Too much of it can raise the risk of metabolic syndrome, type 2 diabetes and heart disease. Brown fat, on the other hand, is packed with mitochondria, which produce energy for cells. This type of fat actually burns calories to generate heat. It’s found in just a few spots in the body: in the front and back of the neck, between the shoulders, and around the heart and kidneys. Scientists are trying to figure out how to expand the amount of brown fat in the body as a possible treatment for obesity. In addition, newer research shows that brown fat can increase the uptake of glucose from the bloodstream2. Harnessing the dual power of brown fat could prove to be a boon for those with type 2 diabetes, especially as 85 percent of those with type 2 are overweight or obese.

Creating Beta Cells from Stem Cells

We’ve heard a lot about stem cells over the past few years, and while it may seem like the hype has died down a bit, in the field of diabetes, stems cells are hot! A team at Harvard has figured out how to transform embryonic stem cells into beta cells, which are the cells in the pancreas that produce insulin. These cells could then be injected into the pancreas to work their magic. The researchers have developed a method that converts the stem cells into beta cells within 30 days. When the new beta cells were injected into mice with diabetes, they went to work right away and essentially cured the mice’s diabetes within 10 days3. More research is needed, but this methodology will hopefully result in the same effect in humans.

Google’s Contact Lens

Google is more than just a search engine. Google scientists have forayed into the healthcare arena and are busy creating contact lenses that contain special sensors. These sensors can detect levels of glucose in tears. Currently, there are two ways that people with diabetes can monitor their blood glucose levels: with a blood glucose meter, which requires finger sticks, and with a continuous glucose monitor, which involves inserting a sensor underneath the skin that measures interstitial glucose. Both methods are invasive. Google has teamed up with Alcon, a division of Novartis, to develop the contact lenses which will contain a microchip and a low-powered circuit. Information about the glucose level in tears (which will be checked once a second), as well as warnings for impending hypoglycemia, will be sent to a mobile device4. Once again, stay tuned!



  1. Russell, SJ, El-Khatib FH, Sinha M et al. Outpatient glycemic control with a bionic pancreas in type 1 diabetes. N Engl J Med 2014; 371:313-325.
  1. Olsen JM, Sato M, Dallner OS. Glucose uptake in brown fat cells is dependent on mTOR complex2-promoted GLUT1 translocation. J Cell Biol 2014; 207:365-374.
  1. Pagliuca FW, Millman JR, Gurtler M et al. Generation of functional human pancreatic B cells in vitro. Cell 2014; 159:428-439.
  1. Otis B and Parvis B. (2014, January 16). Introducing our smart contact lens project. Accessed November 18, 2014 from

Applying the Latest Research: Increasing Protein to Benefit Blood Pressure

Data from the NHANES 2005-2008 surveys shows that more than 30% of adult Americans have high blood pressure (HBP).1 It led to 330,000 deaths among Americans in 20072 and is responsible for more than 7 million deaths annually worldwide.1 In 2010, the healthcare costs and productivity losses related to HBP in the US were estimated to be $76.6 billion.1

Blood pressure is affected by many complex factors, and diet plays a key, but, modifiable role in its development. Therefore, it is important that we identify the impact of specific foods and nutrients on blood pressure in order to formulate effective population-based strategies for HBP prevention.  Dietary patterns, such as the Dietary Approaches to Stop Hypertension (DASH) that is characterized by higher intakes of fruits and vegetables and low-fat dairy, have been shown to have blood pressure-lowering effects in clinical trial settings. 3

Evidence from recent reviews4;5 and meta-analyses6;7 suggests that dietary protein consumption may benefit blood pressure, although questions remain regarding the effects of different types of protein. In fact, there are few observational studies (and no clinical trials) that have addressed the differential long-term effects of animal and plant proteins on blood pressure, and the results of the studies are conflicting.8-10
AJH-Logo-300x44In our current study, we used blood pressure data from 11 years in the Framingham Offspring Study to quantify the long-term effects of different amounts and types of protein on blood pressure, as well as the risk of high blood pressure. We used statistical modeling to account for other factors, such as physical activity or smoking habits, in our analyses. After adjusting for these factors, we saw that higher intake of total protein as well as both animal and plant proteins led to lower systolic and diastolic blood pressures at the follow-up exams. And this was true for both normal-weight and overweight (BMI ≥ 25 kg/m2) middle-aged adults.

We also observed that increased intakes of both animal and plant proteins led to about 30-50% reductions in the risk of HBP. Participants in the highest protein intake category (consuming about 103 g/day) had a 40% lower risk of developing HBP over the next 10 or so years. When people who had higher protein diets also consumed more dietary fiber, there was an even greater benefit – they had a 51% lower risk of HBP.

There are relatively few long-term studies of protein and blood pressure. Overall, we found that there was no adverse effect of either animal or plant protein on HBP risk among these middle-aged adults. In fact, those consuming more protein had significant reductions in high blood pressure risk. Thus, if you’re concerned about your clients’ risk of HBP, we found no reason for you to recommend that they avoid foods containing protein. Finally, since there are many different pathways in the body that lead to HBP, and since different foods and nutrients act on different pathways, we think that it is probably important to consume protein from a variety of sources (e.g., eggs, nuts, dairy, poultry, legumes, soy, meat, fish, etc.).



  1. Vital signs: prevalence, treatment, and control of hypertension–United States, 1999-2002 and 2005-2008. MMWR Morb Mortal Wkly Rep 2011;60:103-108.
  2. Ezzati M, Lopez AD, Rodgers A, Vander HS, Murray CJ. Selected major risk factors and global and regional burden of disease. Lancet 2002;360:1347-1360.
  3. Appel LJ, Moore TJ, Obarzanek E, Vollmer WM, Svetkey LP, Sacks FM, Bray GA, Vogt TM, Cutler JA, Windhauser MM, Lin PH, Karanja N. A clinical trial of the effects of dietary patterns on blood pressure. DASH Collaborative Research Group. N Engl J Med 1997;336:1117-1124.
  4. Altorf-van der Kuil W, Engberink MF, Brink EJ, van Baak MA, Bakker SJ, Navis G, van ‘t V, Geleijnse JM. Dietary protein and blood pressure: a systematic review. PLoS One 2010;5:e12102.
  5. Teunissen-Beekman KF, van Baak MA. The role of dietary protein in blood pressure regulation.Curr Opin Lipidol 2013;24:65-70.
  6. Tielemans SM, Altorf-van der Kuil W, Engberink MF, Brink EJ, van Baak MA, Bakker SJ, Geleijnse JM. Intake of total protein, plant protein and animal protein in relation to blood pressure: a meta-analysis of observational and intervention studies. J Hum Hypertens 2013;27:564-571.
  7. Rebholz CM, Friedman EE, Powers LJ, Arroyave WD, He J, Kelly TN. Dietary protein intake and blood pressure: a meta-analysis of randomized controlled trials. Am J Epidemiol 2012;176 Suppl 7:S27-S43.
  8. Alonso A, Beunza JJ, Bes-Rastrollo M, Pajares RM, Martinez-Gonzalez MA. Vegetable protein and fiber from cereal are inversely associated with the risk of hypertension in a Spanish cohort. Arch Med Res 2006;37:778-786.
  9. Liu K, Ruth KJ, Flack JM, Jones-Webb R, Burke G, Savage PJ, Hulley SB. Blood pressure in young blacks and whites: relevance of obesity and lifestyle factors in determining differences. The CARDIA Study. Coronary Artery Risk Development in Young Adults. Circulation 1996;93:60-66.
  10. Stamler J, Liu K, Ruth KJ, Pryer J, Greenland P. Eight-year blood pressure change in middle-aged men: relationship to multiple nutrients. Hypertension 2002;39:1000-1006.

The Multi-Functional Egg

Chef eggs

NawalToday’s blog post is written by Nawal Al-Nouri, ENC’s Dietetic Intern. Nawal studies Nutrition and Dietetics at the University of Illinois at Chicago, and will be eligible to sit for the RD exam in December of 2013. She maintains a balanced lifestyle by staying active and exposing herself to new ideas, and enjoys cooking and experimenting with different food genres and flavors.

It may be interesting to learn that Columbus’ ships are believed to have carried the first of the chickens related to egg production in America today. It may also surprise you that eggs have several additional functions other than eating them scrambled, fried, poached, baked, in the shell, or as omelets.

Few foods are entirely as versatile as the egg. It has been stated that each of the one-hundred pleats on a chef’s toque represents a different way use eggs, and within each pleat are countless variations. Indisputably, there are other foods or products that can be used to perform similar functions as eggs in a certain setting, however no other food is known to match all properties of the egg. Below are a few unique purposes of the multi-functional egg:

Leaven- Eggs serve as a leavener to increase volume and add lightness to food due to their excellent ability to foam. Eggs, especially the whites, function to leaven soufflés, meringues, angel food cakes and more.


Emulsify- Emulsions may be oil droplets in water, such as mayonnaise or water droplets in fat, such as butter. Egg yolks are considered chemical
emulsifiers, so they have one end that dissolve in water and one dissolved in oil, which helps combine two otherwise immiscible liquids.

Bind & thicken- Eggs act as “glue” and bind ingredients in foods such as meatloaves and casseroles to keep them from crumbling, as well as thicken puddings and sauces.

Impede crystallization- If crystals in candies, frostings, or ice creams form too quickly, they will be small in number but large in size, resulting in an unpleasant grainy texture. Egg whites in particular are introduced as an interfering agent, slowing down the crystallization process to form many fine crystals, bringing about a smooth overall texture.

salmon-150x117Color- The proteins in the eggs influence the browning reactions of foods while the alkaline nature of eggs will help improve browning of acidic products by lowering their acidity. Eggs are responsible for the rich golden glow in custards, egg noodles and béarnaise sauce.

Moisturize & Dry- The fat in the yolk of the egg helps moisturize baked goods, while the white helps give that desired crisp dryness in baked goods such as cream puffs.

The functions of egg whites, egg yolks, and whole eggs are diverse—contributing to its resourcefulness. Adding eggs to your food items provide a wide variety of nutrients, increasing the quantity of essential nutrients specifically in desserts and sauces which may otherwise not provide adequate nutrient value. Check out the American Egg Board’s Eggcyclopedia for a more in depth look at the versatility of eggs.