Last update: 5 May 2020
This page is about eggs, particularly domestic chicken eggs that we eat.
An egg is essentially the whole bird in a shell (albeit with some assembly required), thereby providing the ultimate nose-to-tail eating2. The only essential nutrient for humans that is absent from eggs is vitamin C1. You could do a lot worse than eating only eggs and an ascorbic acid supplement every now and then. In fact, given the palatability reduction5 and satiety factor4 of whole eggs, most people would probably do a lot better – they’d lose weight and improve their metabolic health – for much the same reasons as why the “potato hack”3 works.
Eggs aren’t completely safe for everyone. Much like with dairy, frequent consumption of eggs does not have a very long evolutionary history7 in the human species, and a small minority are allergic6 and should not consume them.
The relationship between egg consumption and cardiovascular disease is, at best, highly unclear8. Beyond raising both HDL and LDL slightly, it seems to have no effect9. What I find the most concerning about eggs is their level of n-6 polyunsaturated fatty acids, which is probably only substantially modifiable by improving the nutrition of the chickens that lay them10.
Some measure of caution is advised concerning raw eggs. Eggs contain a protein called avidin, which binds to the vitamin biotin. Prolonged (over 1 year) consumption of at least six raw eggs per day can cause biotin deficiency, at least in cirrhotic individuals11. Asymptomatic, mild deficiency in the context of a low-biotin diet (notably – without egg yolks) is inducable in a month of heavy raw egg white consumption12. Cooking eggs inactivates avidin, albeit in an incomplete manner unless the cooking is very thorough14. In addition, raw egg proteins are harder to digest than cooked13, likely due to the protease inhibitors they contain15. All that said, if you don’t don’t guzzle half a dozen raw eggs every day for months on end, while having liver damage, you’ll probably be fine.
- Dev Biol. 1990 Jun;139(2):292-8. Regulation of ascorbic acid concentration in embryonic chick brain. Wilson JX1.
- Réhault-Godbert S, Guyot N, Nys Y. The Golden Egg: Nutritional Value, Bioactivities, and Emerging Benefits for Human Health. Nutrients. 2019;11(3):684. Published 2019 Mar 22. doi:10.3390/nu11030684
- Collier R. This spud’s for you: a two-month, tuber-only diet. CMAJ. 2010;182(17):E781‐E782. doi:10.1503/cmaj.109-3719
- Holt, S.H.A. & Brand-Miller, Jennie & Petocz, Peter & Farmakalidis, E. (1995). A Satiety Index of common foods. European journal of clinical nutrition. 49. 675-90.
- Alonso-Alonso M, Woods SC, Pelchat M, et al. Food reward system: current perspectives and future research needs. Nutr Rev. 2015;73(5):296‐307. doi:10.1093/nutrit/nuv002
- Caubet JC, Wang J. Current understanding of egg allergy. Pediatr Clin North Am. 2011;58(2):427‐xi. doi:10.1016/j.pcl.2011.02.014
- Xiang H, Gao J, Yu B, et al. Early Holocene chicken domestication in northern China. Proc Natl Acad Sci U S A. 2014;111(49):17564‐17569. doi:10.1073/pnas.1411882111
- Kuang H, Yang F, Zhang Y, Wang T, Chen G. The Impact of Egg Nutrient Composition and Its Consumption on Cholesterol Homeostasis. Cholesterol. 2018;2018:6303810. Published 2018 Aug 23. doi:10.1155/2018/6303810
- J Am Coll Nutr. 2018 Feb;37(2):99-110. doi: 10.1080/07315724.2017.1366878. Epub 2017 Nov 7. Effects of Egg Consumption on Blood Lipids: A Systematic Review and Meta-Analysis of Randomized Clinical Trials. Rouhani MH1,2, Rashidi-Pourfard N3, Salehi-Abargouei A4,5, Karimi M3, Haghighatdoost F1,2.
- Fatty acid composition of eggs produced by hens fed diets containing groundnut, soya bean or linseed. A.C.Beynen https://doi.org/10.1016/S1573-5214(04)80026-5
- Am J Clin Nutr. 1968 Feb;21(2):173-82. Human biotin deficiency. A case history of biotin deficiency induced by raw egg consumption in a cirrhotic patient. Baugh CM, Malone JH, Butterworth CE Jr.
- Stratton SL, Henrich CL, Matthews NI, et al. Marginal biotin deficiency can be induced experimentally in humans using a cost-effective outpatient design. J Nutr. 2012;142(1):22‐26. doi:10.3945/jn.111.151621
- J Nutr. 1998 Oct;128(10):1716-22. Digestibility of cooked and raw egg protein in humans as assessed by stable isotope techniques. Evenepoel P1, Geypens B, Luypaerts A, Hiele M, Ghoos Y, Rutgeerts P.
- Durance, Timothy. (2006). Residual Avid in Activity in Cooked Egg White Assayed with Improved Sensitivity. Journal of Food Science. 56. 707 – 709. 10.1111/j.1365-2621.1991.tb05361.x.
- Cell Mol Life Sci. 1997 Jan;53(1):13-23. Protein proteinase inhibitors from avian egg whites. Saxena I1, Tayyab S.