Nutrients In Eggs

Eggs are a nutrient goldmine!

One large egg has varying amounts of 13 essential vitamins and minerals, high-quality protein, all for 70 calories.

While egg whites contain some of the eggs’ high-quality protein, riboflavin and selenium, the majority of an egg’s nutrient package is found in the yolk. Nutrients such as:

  • Vitamin D, critical for bone health and immune function. Eggs are one of the only foods that naturally contain vitamin D.
  • Choline, essential for normal functioning of all cells, but particularly important during pregnancy to support healthy brain development of the fetus.
  • Lutein and zeaxanthin, antioxidants that are believed to reduce the risk of developing cataracts and slow the progression of age-related macular degeneration, a disease that develops with age.

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.

Cited:

  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.

High-Quality Protein on a Budget

Eggs-One-CrackedWhile dangerously high rates of obesity today are no secret, scientists and health professionals continually strive to find obesity’s root causes, in an effort to combat related alarming health trends. In their searches, researchers have found a link between obesity and chronic diseases due to consumption of high energy dense foods such as refined sugars, grains and processed convenience foods. Simultaneously, several studies have shown that high energy-dense diets may be cheaper than diets based around nutrient-dense foods such as meats, fruits and vegetables, making them particularly appealing to the low socioeconomic population (1,2,3). Health professionals’ dietary recommendations may indeed be limited by what patients can afford. However, high-quality protein sources, such as eggs, can be an affordable and nutritious option for populations with limited food budgets.Obesity is inarguably a multi-causal state, but research has demonstrated that two major factors in the development of obesity are education and income levels (1). The National Institutes of Health (NIH) has found that the availability of inexpensive food items to poverty-stricken areas correlates with higher energy intakes, but lower intakes of macronutrients such as protein, complex carbohydrates and fiber (2). Therefore, adults consuming these diets are less likely to feel satiated after their meals and often have an increased intake of saturated fats and added sugars. This can cause a state of overfeeding and undernourishment including low intakes of iron, zinc, vitamin D and vitamin B-12 (3) .

Given the different metabolic pathways of macronutrients during digestion, strategic adjustment of the proportions of intake from protein, carbohydrate and fat may help to combat obesity. Protein, for instance, has a higher satiety value than carbohydrates and therefore has been shown to reduce overall caloric intake. A 2013 study found that when people ate high-quality protein that consisted of an egg- and beef-rich breakfast, they had greater satiety between meals, which reduced appetite-regulating hormone levels and food cravings (4) and in another study, lowered energy intake by 130 calories, compared to those who ate a refined cereal breakfast (5). Also, two studies found that men who ate 25 percent more than the Recommended Dietary Allowance (RDA) for protein were able to decrease hunger and the amount of energy dense foods consumed (6,7).

Eggs are a source of high-quality protein, providing 6 grams or 12% of the Daily Value (DV), at only 70 calories per egg. A single egg also provides 10% of the DV for vitamin D, 15% for riboflavin, 8% for vitamin B12 and 4% for iron (8). At only 16 cents apiece on average, eggs are a nutritional bargain, providing one of the least expensive sources of high-quality protein per dollar spent (9). As such, eggs can help fill nutrient gaps in the diet; and health professionals can feel confident recommending this high-quality protein source as a means to help combat obesity and micronutrient deficiencies.

 

  1. Adam Drewnowski, Obesity and the food environment: Dietary energy density and diet   costs, American Journal of Preventive Medicine, Volume 27, Issue 3, Supplement, October 2004, Pages 154-162, ISSN 0749-3797, http://dx.doi.org/10.1016/j.amepre.2004.06.011.
  2. Symposium: Modifying the Food Environment: Energy Density, Food Costs, and Portion Size: Adam Drewnowski and Nicole Darmon. Food Choices and Diet Costs: an Economic Analysis J. Nutr. 2005 135: 4 900-904. http://www.biomedcentral.com.archer.luhs.org/content/pdf/1743-7075-6-12.pdf.
  3. Miller, B. D., & Welch, R. M. (2013). Food system strategies for preventing micronutrient malnutrition. Food Policy, 42, 115-128.
  4. Leidy HJ, Ortinau LC, Douglas SM, Hoertel HA. Beneficial effects of a higher-protein breakfast on the appetitive, hormonal, and neural signals controlling energy intake regulation in overweight/obese “breakfast-skipping” late-adolescent girls. Am J Clin Nutr 2013; 97(4):677-88.
  5. Leidy HJ, Racki EM. The addition of a protein-rich breakfast and its effect on acute appetite control and food intake in ‘breakfast skipping’ adolescents. Int J Obs 2010; 43(7):1125-33.
  6. Layman DK. Protein quantity and quality at levels above RDA improves adult weight loss. J Am Coll Nutr 2004; 23(6):631S-6S.
  7. Weigle DS, Breen PA, Matthys CC, Callahan HS, Meeuws KE, Burden VR, Purnell JQ. A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations. Am J Clin Nutr 2005; 82(1):41-8.
  8. Egg Nutrition Center. Egg Nutrition Facts Label (2014). Retrieved on October 16, 2014 from https://www.eggnutritioncenter.org/egg-facts/.
  9. United States Department of Agriculture. Economic Research Service. Retail data for beef, pork, poultry cuts, eggs, and dairy products (October 2013). Retrieved on October 22, 2014 from http://www.ers.usda.gov/Data/MeatPriceSpreads/

The Egg Yolk: A Goldmine of Nutrition + Recipe for Apple Cheddar Bread Pudding Bites


Serena-Ball-headshotToday’s post comes from Serena Ball, MS, RD. Based in St. Louis, registered dietitian Serena Ball is co-founder of TheRecipeReDux.com blogs at TeaspoonOfSpice.com. She is a nutrition writer and social media expert. Serena’s flavor-focused food writing has appeared in RelishSpry and Parents, and CookingLight.com.

Don’t toss those yolks!

As a registered dietitian, I am surprised to hear it suggested that the healthiest way to eat an egg is to cook up the whites only and toss those bright yellow yolks. The reality is that just as with other vividly colored foods – kale or red leaf lettuce versus iceberg – the bright color of a yolk signals it contains some of the highest concentration of nutrients.

Here’s what can be found in an egg yolk1:

  • 42% of the protein in an egg – While it’s generally well-known that egg whites contain protein, the yolk contains more than 2.5 grams of the total 6 grams of high-quality protein found in an egg.
  • 59% of the selenium in an egg – Relatively few foods contain the important antioxidant selenium which regulates thyroid function and helps prevent cell damage. It is found in Brazil nuts and mainly animal sources such as fish, poultry and beef.
  • 100% of the zinc in an egg – Only the yolk contains the mineral zinc, which is especially important for normal growth and development during pregnancy; it’s also necessary for wound healing and immunity. For people who don’t eat much meat, egg yolks are one of the few sources of this nutrient.
  • 100% of the iron in an egg – Necessary for muscle and other cell growth in the body, children and older adults are two populations which tend to have low iron intake – and thus can benefit from consuming eggs, which are the inexpensive and easy-to-chew. Other sources of iron include meat, fortified cereals and to a lesser degree, beans.
  • 100% of the vitamin B6 in an egg – Folks who consume egg whites for protein miss out on the vitamin B6 found in the yolk; this is unfortunate because vitamin B6 is critical for protein metabolism. Vitamin B6 is also important in immune function. It is found mainly in meat and poultry – but to some extent in fortified cereals and beans.
  • 100% of the choline in an egg – Choline is one of the most important reasons that pregnant women should consume eggs, as it is critical for brain development of a baby. The nutrient choline is also necessary for normal functioning of all cells. Choline is found in few other foods as commonly consumed as egg yolks; it’s available in beef liver and chicken livers, cod and smaller amounts in cauliflower.

Eggs contain many other important nutrients (a list of which can be found here,) but the above were highlighted because eggs are one of the few natural sources of these nutrients, which are not found in other commonly consumed foods. At only about $0.15 per egg, the whole egg – yolk and white together – is one of the most affordable sources of high-quality protein and good nutrition available2.

And remember, ‘An egg a day is OK’ – especially when it keeps company on the plate with whole grains, fruits and vegetables. To enjoy eggs for breakfast, lunch, a light dinner or even dessert, I created this recipe using fruit, whole grains, low-fat dairy and one whole egg per person. Make in a muffin pan to serve as breakfast or dessert – or serve for brunch as a casserole!

Apple Cheddar Bread Pudding Squares

Apple Cheddar Bread Pudding Bites

(Serves 6)

6 eggs, beaten

1 ¾ cups low-fat milk

½ cup sugar

¼ teaspoon nutmeg

4 cups cubed whole wheat bread

1 large (or 1 ½ medium) apple, unpeeled, cored and finely chopped

¾ cup (3 ounces) low-fat Cheddar cheese, grated

Preheat oven to 350°F. Spray 9×13-inch baking dish with non-stick cooking spray.

In a large bowl beat together eggs, milk, sugar, nutmeg. Gently fold in bread and apple; let set for 10 minutes for bread to soak up mixture. Pour mixture into prepared baking dish; sprinkle with cheese. Bake for 40-45 minutes or until knife inserted near the center comes out clean.

Optional: Can also be scooped evenly into greased two standard-sized 6-cup muffin pans; sprinkle with cheese. Bake for 30-35 minutes. Makes 12 muffin cups; serving is 2 muffin cups.

 

Disclosure: I was asked to write this post; and as big fan of eggs and a member of the Egg Nutrition Center Health Professionals Advisory Panel, I was happy to oblige. I am compensated for being a Health Professional Advisor. Opinions are my own.

 

References:

  • S. Department of Agriculture, Agricultural Research Service, USDA Nutrient Data Laboratory. 2010. USDA National Nutrient Database for Standard Reference, Release 23. www.ars.usda.gov/nutrientdata.
  • United States Department of Agriculture. Economic Research Service. Retail data for beef, pork, poultry cuts, eggs, and dairy products (October 2013). Retrieved on September 17, 2014 from http://www.ers.usda.gov/Data/MeatPriceSpreads/

Leucine: Promoting Muscle Anabolism at Breakfast

Muscle Illustration

Protein is a critically important fuel source for muscles, and branched chain amino acids (BCAAs) are particularly so. Leucine is the most abundant BCAA found in muscles, and as the body of leucine research continues to grow, so does the evidence pointing to several benefits that leucine imparts, including the regulation of skeletal muscle protein synthesis. This was demonstrated in a study where leucine supplementation in a low dose of whey protein stimulated postprandial human myofibrillar protein synthesis as effectively as a much greater dose of whey protein (1). Similarly, a low-protein mixed macronutrient beverage supplemented with a high amount of leucine was found to be as effective as a high-protein beverage at stimulating muscle anabolism (2). Furthermore, results of another study on muscle recovery suggest that increasing the concentration of leucine in an essential amino acid supplement during moderate intensity exercise may increase post-exercise skeletal muscle metabolism (3). In addition to tissue protein synthesis, leucine in combination with vitamin B6 also increased fat oxidation and insulin sensitivity and reduced oxidative and inflammatory stress, thus suggesting a potential approach in the management of obesity (4).

Leucine-3D

Leucine is an essential amino acid, and as such, it must be obtained from dietary sources, since our bodies cannot produce it. Animal proteins in general are among the best sources of dietary leucine. Eggs contain 1.086g of leucine per 100g weight, which translates to approximately 9% of its total protein content (5). When compared to other foods commonly consumed for breakfast, eggs are not as high on a gram for gram basis as oats or cheese (see figure below). However, when a comparison of leucine content is made on a per calorie basis, eggs come out looking better than most other common food sources. At only 72 calories, with 6.3 grams of protein and a high leucine content, eggs are a nutritionally- and protein-dense food source, perfect for those trying to get a little more protein, leucine and other essential micronutrients in their diets.

Charts_Leucine-in-Breakfast-Protein

As noted in the dialogue from the recent fourth meeting of the Dietary Guidelines Advisory Committee, protein is notoriously under-consumed at breakfast. Given their robust nutrient profile and leucine content, eggs can be an easy fix to this nutritional shortcoming and an important protein source to consider when helping patients and clients build healthful diets.

References:

  1. Churchward-Venne TA, Burd NA, Mitchell CJ, West DW, Philp A, Marcotte GR, Baker SK, Baar K, Phillips SM. Supplementation of a suboptimal protein dose with leucine or essential amino acids: effects on myofibrillar protein synthesis at rest and following resistance exercise in men. J Physiol. 20012; 590(Pt 11):2751-65.
  2. Churchward TA, Breen L, Di Donato DM, Hector AJ, Mitchell CJ, Moore DR, Stellingwerff T, Breuille D, Offord EA, Baker SK, Phillips SM. Leucine supplementation of a low-protein mixed macronutrient beverage enhances myofibrillar protein synthesis in young men: a double-blind, randomized trial.Am J Clin Nutr. 2014; 99(2):276-86.
  3. Pasiakos SM, MClung HL, McClung JP, Margolis LM, Andersen NE, Cloutier GJ, Pikosky MA, Rood JC, Fielding RA, Young AJ. Leucine-enriched essential amino acid supplementation during moderate steady state exercise enhances postexercise muscle protein synthesis. Am J Clin Nutr. 2011; 94(3):809-18.
  4. Zemel MB, Bruckbauer A. Effects of a leucine and pyridoxine-containing nutraceutical on fat oxidation, and oxidative and inflammatory stress in overweight and obese subjects. Nutrients. 2012; 4(6):529-41.
  5. USDA National Nutrient Database for Standard Reference. U.S. Department of Agriculture, Agricultural Research Service, USDA Nutrient Data Laboratory Website. Updated Dec 7, 2011.http://ndb.nal.usda.gov/. Accessed July 28, 2014.