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A shelled vessel for protein and fats in the white and yolk, respectively, that carries a surprisingly large amount of nutrients; especially choline and leucine as well as many carotenoids coloring the yolk. Eggs do not inherently increase circulating cholesterol.

Our evidence-based analysis on eggs features 102 unique references to scientific papers.

Research analysis led by and reviewed by the Examine team.
Last Updated:

Research Breakdown on Eggs

(Note: Every egg is different since every hen is different, and dietary factors affect composition of the egg[1][2][3][4])

The Yolk contains:

  • Dietary Fats and lipids,[5] of which the PUFA content may be affected by hen diet[6]

  • Dietary Cholesterol

  • Vitamin E, which decreases with time and may be reduced by 50% over 40 days (refrigerated)[6]

  • Apovitellinin-I, vitellogenin-1,2 and 3, and apolipoprotein B.[7]

  • Immunoglobulins[8] and Antibodies[9]

  • May contain different scented and tasting molecules dependent on feed[10]

  • Binding proteins for Thaimin, Riboflavin, Niacin, Vitamin D, Vitamin A, and cobalamin; as well as the respective vitamins.[11]

  • Pantothenic Acid (Vitamin B5)[12]

  • The bioactive peptide YPEP, which has bone-protective properties.[13]

The White contains:[14]

  • A wide variety of proteins (78 analyzed with high confidence, 148 overall confirmed, 202 possible) that have (mostly) non-nutritive implications.[14]

  • Ovalbumin, Ovotransferrin, and Ovomucoid (collectively 75% of total protein content)[14]

  • Anti-microbial lysosomes[15]

  • Biotin-binding protein Avidin[16]

  • Riboflavin and Biotin[11]

Additionally, the shell contains:

  • Dietary Calcium (as Calcium carbonate)[17]

  • Apovitellenin-I and Vitellogenins (1-3)[18]

  • Ovocleidin-17 and 116, Ovocalyxin-32 and 36, clusterin and Kunitz-like protease inhibitor[19]

  • Uronic Acid[20]

  • Glycosaminoglycans (correlated with shell physical strength)[21]


  1. ^ McNaughton JL. Effect of dietary fiber on egg yolk, liver, and plasma cholesterol concentrations of the laying hen. J Nutr. (1978)
  2. ^ Shang XG, et al. Effects of dietary conjugated linoleic acid on the productivity of laying hens and egg quality during refrigerated storage. Poult Sci. (2004)
  3. ^ Bolden SL, Jensen LS. The effect of marginal levels of calcium, fish meal, torula yeast and alfalfa meal on feed intake, hepatic lipid accumulation, plasma estradiol, and egg shell quality among laying hens. Poult Sci. (1985)
  4. ^ Hodzic A, et al. The influence of dietary palm olein, fish oil and lard on the egg yolk and plasma lipid composition, and performances of laying hens. Pol J Vet Sci. (2008)
  5. ^ Kuksis A. Yolk lipids. Biochim Biophys Acta. (1992)
  6. ^ a b Hayat Z, et al. Oxidative stability and lipid components of eggs from flax-fed hens: effect of dietary antioxidants and storage. Poult Sci. (2010)
  7. ^ Burley RW, Evans AJ, Pearson JA. Molecular aspects of the synthesis and deposition of hens' egg yolk with special reference to low density lipoprotein. Poult Sci. (1993)
  8. ^ Vega C, et al. Egg yolk IgY: protection against rotavirus induced diarrhea and modulatory effect on the systemic and mucosal antibody responses in newborn calves. Vet Immunol Immunopathol. (2011)
  9. ^ Guimar√£es MC, et al. Growth inhibition of Staphylococcus aureus by chicken egg yolk antibodies. Arch Immunol Ther Exp (Warsz). (2009)
  10. ^ Plagemann I, et al. Volatile flavours in raw egg yolk of hens fed on different diets. J Sci Food Agric. (2011)
  11. ^ a b White HB 3rd. Vitamin-binding proteins in the nutrition of the avian embryo. J Exp Zool Suppl. (1987)
  12. ^ Rychlik M. Pantothenic acid quantification by a stable isotope dilution assay based on liquid chromatography-tandem mass spectrometry. Analyst. (2003)
  13. ^ Kim HK, Lee S, Leem KH. Protective effect of egg yolk peptide on bone metabolism. Menopause. (2011)
  14. ^ a b c Mann K, Mann M. In-depth analysis of the chicken egg white proteome using an LTQ Orbitrap Velos. Proteome Sci. (2011)
  15. ^ Yoon J, et al. Antimicrobial activity of the cell organelles, lysosomes isolated from egg white. J Microbiol Biotechnol. (2009)
  16. ^ White HB 3rd, et al. Biotin-binding protein from chicken egg yolk. Assay and relationship to egg-white avidin. Biochem J. (1976)
  17. ^ Cordeiro CM, Hincke MT. Recent patents on eggshell: shell and membrane applications. Recent Pat Food Nutr Agric. (2011)
  18. ^ Mann K, Macek B, Olsen JV. Proteomic analysis of the acid-soluble organic matrix of the chicken calcified eggshell layer. Proteomics. (2006)
  19. ^ Determination of insoluble avian eggshell matrix proteins.
  20. ^ Nakano T, Ikawa NI, Ozimek L. Chemical composition of chicken eggshell and shell membranes. Poult Sci. (2003)
  21. ^ Ha YW, et al. Relationship between eggshell strength and keratan sulfate of eggshell membranes. Comp Biochem Physiol A Mol Integr Physiol. (2007)
  22. Ohman M, et al. Biochemical effects of consumption of eggs containing omega-3 polyunsaturated fatty acids. Ups J Med Sci. (2008)
  23. Bovet P, et al. Decrease in blood triglycerides associated with the consumption of eggs of hens fed with food supplemented with fish oil. Nutr Metab Cardiovasc Dis. (2007)
  24. Goodrow EF, et al. Consumption of one egg per day increases serum lutein and zeaxanthin concentrations in older adults without altering serum lipid and lipoprotein cholesterol concentrations. J Nutr. (2006)
  25. Vishwanathan R, et al. Consumption of 2 and 4 egg yolks/d for 5 wk increases macular pigment concentrations in older adults with low macular pigment taking cholesterol-lowering statins. Am J Clin Nutr. (2009)
  26. Zeisel SH, da Costa KA. Choline: an essential nutrient for public health. Nutr Rev. (2009)
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  32. Nakamura Y, et al. Egg consumption, serum total cholesterol concentrations and coronary heart disease incidence: Japan Public Health Center-based prospective study. Br J Nutr. (2006)
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  35. Scrafford CG, et al. Egg consumption and CHD and stroke mortality: a prospective study of US adults. Public Health Nutr. (2011)
  36. Hu FB, et al. A prospective study of egg consumption and risk of cardiovascular disease in men and women. JAMA. (1999)
  37. Djouss√© L, Gaziano JM. Egg consumption in relation to cardiovascular disease and mortality: the Physicians’ Health Study. Am J Clin Nutr. (2008)
  38. Fuller NR, et al. The effect of a high-egg diet on cardiovascular risk factors in people with type 2 diabetes: the Diabetes and Egg (DIABEGG) study-a 3-mo randomized controlled trial. Am J Clin Nutr. (2015)
  39. Ballesteros MN, et al. One Egg per Day Improves Inflammation when Compared to an Oatmeal-Based Breakfast without Increasing Other Cardiometabolic Risk Factors in Diabetic Patients. Nutrients. (2015)
  40. Blesso CN, et al. Whole egg consumption improves lipoprotein profiles and insulin sensitivity to a greater extent than yolk-free egg substitute in individuals with metabolic syndrome. Metabolism. (2013)
  41. Blesso CN, et al. Effects of carbohydrate restriction and dietary cholesterol provided by eggs on clinical risk factors in metabolic syndrome. J Clin Lipidol. (2013)
  42. Njike V, et al. Daily egg consumption in hyperlipidemic adults--effects on endothelial function and cardiovascular risk. Nutr J. (2010)
  43. Rueda JM, Khosla P. Impact of breakfasts (with or without eggs) on body weight regulation and blood lipids in university students over a 14-week semester. Nutrients. (2013)
  44. Djoussé L, et al. Egg consumption and risk of type 2 diabetes in older adults. Am J Clin Nutr. (2010)
  45. Ra.dzevińćienńó L, Ostrauskas R. Egg consumption and the risk of type 2 diabetes mellitus: a case-control study. Public Health Nutr. (2012)
  46. Djoussé L, et al. Egg consumption and risk of type 2 diabetes in men and women. Diabetes Care. (2009)
  47. Shi Z, et al. Egg consumption and the risk of diabetes in adults, Jiangsu, China. Nutrition. (2011)
  48. Pearce KL, Clifton PM, Noakes M. Egg consumption as part of an energy-restricted high-protein diet improves blood lipid and blood glucose profiles in individuals with type 2 diabetes. Br J Nutr. (2011)
  49. Harris RC, Söderlund K, Hultman E. Elevation of creatine in resting and exercised muscle of normal subjects by creatine supplementation. Clin Sci (Lond). (1992)
  50. Diet and Refsum's disease. The determination of phytanic acid and phytol in certain foods and the application of this knowledge to the choice of suitable convenience foods for patients with Refsum's disease.
  51. Rawson ES, et al. Creatine supplementation does not improve cognitive function in young adults. Physiol Behav. (2008)
  52. Benton D, Donohoe R. The influence of creatine supplementation on the cognitive functioning of vegetarians and omnivores. Br J Nutr. (2011)
  53. Phytanic acid: measurement of plasma concentrations by gas–liquid chromatography–mass spectrometry analysis and associations with diet and other plasma fatty acids.
  54. Koeth RA, et al. Intestinal microbiota metabolism of l-carnitine, a nutrient in red meat, promotes atherosclerosis. Nat Med. (2013)
  55. W.H. Wilson Tang, et al. Intestinal microbial metabolism of phosphatidylcholine and cardiovascular risk. N Engl J Med. (2013)
  56. Holt SH, et al. A satiety index of common foods. Eur J Clin Nutr. (1995)
  57. Drewnowski A, Rehm CD. Vegetable cost metrics show that potatoes and beans provide most nutrients per penny. PLoS One. (2013)
  58. Nanayakkara WS, et al. Efficacy of the low FODMAP diet for treating irritable bowel syndrome: the evidence to date. Clin Exp Gastroenterol. (2016)
  59. van Jaarsveld PJ, et al. Beta-carotene-rich orange-fleshed sweet potato improves the vitamin A status of primary school children assessed with the modified-relative-dose-response test. Am J Clin Nutr. (2005)
  60. Lobo GP, et al. Genetics and diet regulate vitamin A production via the homeobox transcription factor ISX. J Biol Chem. (2013)
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  62. Novotny JA, et al. Beta-carotene conversion to vitamin A decreases as the dietary dose increases in humans. J Nutr. (2010)
  63. Nosworthy MG, et al. Determination of the protein quality of cooked Canadian pulses. Food Sci Nutr. (2017)
  64. Ganesan K, Xu B. Polyphenol-Rich Lentils and Their Health Promoting Effects. Int J Mol Sci. (2017)
  65. Njoumi S, et al. Soaking and cooking modify the alpha-galacto-oligosaccharide and dietary fibre content in five Mediterranean legumes. Int J Food Sci Nutr. (2019)
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  67. Kalt W, et al. Recent Research on the Health Benefits of Blueberries and Their Anthocyanins. Adv Nutr. (2020)
  68. Basu A, et al. Strawberries decrease atherosclerotic markers in subjects with metabolic syndrome. Nutr Res. (2010)
  69. Sissener NH. Are we what we eat? Changes to the feed fatty acid composition of farmed salmon and its effects through the food chain. J Exp Biol. (2018)
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  73. Simopoulos AP. The importance of the ratio of omega-6/omega-3 essential fatty acids. Biomed Pharmacother. (2002)
  74. Provenza FD, Kronberg SL, Gregorini P. Is Grassfed Meat and Dairy Better for Human and Environmental Health?. Front Nutr. (2019)
  75. Daley CA, et al. A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef. Nutr J. (2010)
  76. Ehr IJ, Persia ME, Bobeck EA. Comparative omega-3 fatty acid enrichment of egg yolks from first-cycle laying hens fed flaxseed oil or ground flaxseed. Poult Sci. (2017)
  77. Anderson KE. Comparison of fatty acid, cholesterol, and vitamin A and E composition in eggs from hens housed in conventional cage and range production facilities. Poult Sci. (2011)
  78. Egg intake does not change plasma lipoprotein and coagulation profiles.
  79. Bowman MP, et al. Effect of dietary fat and cholesterol on plasma lipids and lipoprotein fractions in normolipidemic men. J Nutr. (1988)
  80. Chenoweth W, et al. Influence of dietary cholesterol and fat on serum lipids in men. J Nutr. (1981)
  81. Effect of dietary eggs and ascorbic acid on plasma lipid and lipoprotein cholesterol levels in healthy young men.
  82. Down-regulation of the low-density lipoprotein receptor by dietary cholesterol.
  83. Johnson C, Greenland P. Effects of exercise, dietary cholesterol, and dietary fat on blood lipids. Arch Intern Med. (1990)
  84. Sacks FM, et al. Ingestion of egg raises plasma low density lipoproteins in free-living subjects. Lancet. (1984)
  85. Flynn MA, et al. Serum lipids and eggs. J Am Diet Assoc. (1986)
  86. Fernandez ML. Dietary cholesterol provided by eggs and plasma lipoproteins in healthy populations. Curr Opin Clin Nutr Metab Care. (2006)
  87. A double-blind, randomized, controlled trial of the effects of two eggs per day in moderately hypercholesterolemic and combined hyperlipidemic subjects taught the NCEP step I diet.
  88. Romano G, et al. Effects of dietary cholesterol on plasma lipoproteins and their subclasses in IDDM patients. Diabetologia. (1998)
  89. Mayurasakorn K, et al. High-density lipoprotein cholesterol changes after continuous egg consumption in healthy adults. J Med Assoc Thai. (2008)
  90. Katz DL, et al. Egg consumption and endothelial function: a randomized controlled crossover trial. Int J Cardiol. (2005)
  91. Jones PJ. Dietary cholesterol and the risk of cardiovascular disease in patients: a review of the Harvard Egg Study and other data. Int J Clin Pract Suppl. (2009)
  92. Dietary cholesterol from eggs increases the ratio of total cholesterol to high-density lipoprotein cholesterol in humans: a meta-analysis.
  93. Fernandez ML. Effects of eggs on plasma lipoproteins in healthy populations. Food Funct. (2010)
  94. McNamara DJ. The impact of egg limitations on coronary heart disease risk: do the numbers add up. J Am Coll Nutr. (2000)
  95. Fernandez ML, Calle M. Revisiting dietary cholesterol recommendations: does the evidence support a limit of 300 mg/d. Curr Atheroscler Rep. (2010)
  96. Eggs, serum cholesterol, and coronary heart disease.
  97. Herron KL, et al. High intake of cholesterol results in less atherogenic low-density lipoprotein particles in men and women independent of response classification. Metabolism. (2004)
  98. Spence JD, Jenkins DJ, Davignon J. Dietary cholesterol and egg yolks: not for patients at risk of vascular disease. Can J Cardiol. (2010)
  99. Hays JH, et al. Effect of a high saturated fat and no-starch diet on serum lipid subfractions in patients with documented atherosclerotic cardiovascular disease. Mayo Clin Proc. (2003)
  100. Mutungi G, et al. Dietary cholesterol from eggs increases plasma HDL cholesterol in overweight men consuming a carbohydrate-restricted diet. J Nutr. (2008)
  101. Mutungi G, et al. Eggs distinctly modulate plasma carotenoid and lipoprotein subclasses in adult men following a carbohydrate-restricted diet. J Nutr Biochem. (2010)
  102. Fern√°ndez-Robredo P, et al. Egg yolk improves lipid profile, lipid peroxidation and retinal abnormalities in a murine model of genetic hypercholesterolemia. J Nutr Biochem. (2008)