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Eggs and cholesterol: Where do we stand?

Eggs have long been a staple food in different parts of the world, and are not only considered an economical and nutritious source of protein, but also a high source of cholesterol. Hence, there have been mixed messages around their effect on cardiovascular health in the mainstream media as well as in international nutritional guidelines aimed at reducing plasma cholesterol levels and the risk of cardiovascular disease.1 Nevertheless, research in this field has evolved considerably in recent años. So where do we stand today? Here is a brief overview of the current state of knowledge and recommendations on this issue.

Current state of research

Evidence from recent large-scale cohort studies is inconsistent, but most come to similar conclusions: moderate or higher egg consumption (the equivalent of 7 eggs or more per week) does not appear to be associated with an increased cardiovascular disease risk and mortality overall.1,2,3,4 On the other hand, a large study published in 2021 reported that eating more eggs and cholesterol was associated with higher mortality from all causes, cardiovascular disease and cancer.5 However, these contradictory findings have been debated in the scientific community, which has pointed out some important limitations of the study from which no definitive conclusions can be drawn on a broad scale at this point.6,7

Another issue must be addressed. Unlike interventional studies, most of these studies are based on observations and cannot, by their very nature, establish a cause and effect relationship. As a matter of fact, the regular human diet is usually composed of many different foods, which makes it difficult to assess the health effects of a single component (e.g. eggs) outside the context of a dietary pattern. In other words, these results cannot demonstrate whether eating more eggs increases the risk of cardiovascular disease, since the latter may be influenced by many other lifestyle factors at the same time.

In fact, dietary cholesterol appears to have only a modest effect on blood cholesterol levels although some individuals may be ‘hyper-responders’. This means that cholesterol intake may have a greater impact on the cholesterol levels of these people than on the average population. More generally, it is known that other food components, such as saturated and trans fatty acids, have a greater influence on cholesterol levels.8,9

Nutritional guidelines

International and national nutrient recommendations also reflect these recent findings. The current official guidelines published for the global population (FAO/WHOa)10 and for the populations of the United States, the European Union, the United Kingdom, Canada, Australia, New Zealand, the People’s Republic of China, and the Republic of China (Taiwan),11,12,13,14,15,16,17 among others, do not set dietary cholesterol reference values, although this has not always been the case.18,19 However, the penultimate edition of the US dietary guidelines (2015-2020) emphasised that the lifting of the previous restriction of 300 mg of cholesterol per day did not necessarily mean that dietary cholesterol should no longer be considered.20 Keeping a cholesterol intake as low as possible remains a common approach in most recommendations.

Still, there are a few exceptions, as is the case in Japan, where a maximum daily intake of 200 mg of cholesterol is advised in order to prevent the onset of severe dyslipidaemias (i.e. abnormal plasma lipid levels) based on the guidelines from the Japan Atherosclerosis Society.21,22 In addition, a limit of 300 mg of dietary cholesterol per day has been recommended by the European Society of Cardiology and the European Atherosclerosis Society for the management of dyslipidaemias (especially in people with high serum cholesterol levels),9 and by the UK National Institute for Health and Care Excellence for individuals at high risk of or with cardiovascular disease.23,24

In fact, dietary cholesterol appears to have only a modest effect on blood cholesterol levels although some individuals may be ‘hyper-responders’. This means that cholesterol intake may have a greater impact on the cholesterol levels of these people than on the average population.

Sources of dietary cholesterol

Eggs have often served as an example due to their high cholesterol content, but you may be aware that cholesterol also occurs naturally in a range of other products, with the exception of plant-based products. The main food sources of dietary cholesterol include eggs, fatty meat (e.g. some cuts like ribeye steak, spare ribs, lamb shoulder), processed meat (e.g. ground pork, sausage, salami), offal (e.g. veal kidney, sweetbread, pork cheek), full-fat milk and derived dairy products (e.g. regular cheese, yogurt, cream), animal fats (e.g. butter, lard, bacon fat), and seafood (especially shellfish).1,8,9,25

While some foods are high in both cholesterol and saturated fatty acids, such as fatty meat, processed meat, full-fat dairy products, and animal fats, others are high in cholesterol but not in saturated fat. This is the case for eggs, shellfish and certain organ meats (e.g. sweetbread, chicken liver).1,8 As an indication, a medium-sized egg contains 185-200 mg of cholesterol but only 1.3-1.6 g of saturated fat on average (i.e. less than 1% of an estimated daily energy value of 2000 kcal provided by saturated fat), based on the American and French food composition tables.26,27

How many eggs can I eat?

This question, which many people still ask themselves or their health practitioners, has also been discussed at length in the media. Nevertheless, most dietary recommendations do not set a specific frequency for egg consumption. Only some expert groups and countries have proposed a limit for both healthy individuals and those with certain medical conditions or an increased risk of cardiovascular disease. Some examples are listed below:

  • American Heart Association (AHA): up to 1 egg per day for healthy individuals and up to 2 eggs per day for older people with normal cholesterol levels, as part of a healthy diet. On the other hand, the AHA suggests that patients with dyslipidaemia (especially those with type 2 diabetes or at risk of heart failure) should be cautious about their dietary cholesterol intake;1
  • National Heart Foundations of Australia and New Zealand: eggs can be consumed as part of healthy eating patterns for people without cardiovascular disease or type 2 diabetes. In contrast, a maximum of 7 eggs per week has been set for people with type 2 diabetes, cardiovascular disease or at high risk of heart disease;28,29
  • National dietary guidelines of the People’s Republic of China: up to 7 eggs per week for healthy individuals;30
  • National dietary guidelines of Taiwan: up to 1 egg per day for healthy people, but less than 1 egg per day for those at higher risk of cardiovascular disease (e.g. with hypercholesterolemia, obesity) or with cardiovascular disease.31

A heart-healthy diet

Note that some lifestyle changes may have a greater impact on the prevention and management of cardiovascular disease risk and dyslipidaemia than simply limiting egg consumption. While reducing cholesterol intake is not among the strongest recommendations, here are some key pieces of advice for a heart-healthy diet that you may want to remember:

  • Increase your dietary fibre intake by focusing on wholegrain products, vegetables, fruit, legumes, and nuts;
  • Limit your consumption of foods rich in saturated fatty acids (full-fat dairy products, fatty cuts of meat, animal fats, and products containing tropical vegetable oils such as coconut and palm oils) and favour fish, poultry without skin, and plant-based protein sources like legumes and soy products;
  • Opt for sources of unsaturated fats, such as vegetable oils (derived from olives, rapeseed, sunflower, soybean, etc.), nuts (e.g. almonds, walnuts, hazelnuts) and seeds (e.g. pumpkin seeds, flaxseeds);
  • Limit your intake of trans fatty acids as much as possible, especially those of industrial origin, i.e. partially hydrogenated fatty acids found in processed foods like some frying oils, biscuits, pastries, snacks, etc.9,32

Conclusion

Although the impact of egg consumption on cardiovascular disease risk is not yet fully understood, eggs remain a nutritious option as part of a diversified and healthy diet. They are a complete source of protein with all the essential amino acids, and are therefore suitable for omnivorous and lacto-ovo vegetarian diets. Eggs also contain good amounts of vitamin A, vitamin D, vitamin B12, iron, zinc, and a range of other nutrients beneficial to your health.26,28

Alongside the key recommendations for a heart-healthy diet, it may be safer to limit your cholesterol intake until the study findings are perhaps more unequivocal, especially if you are at high risk for cardiovascular disease or have cardiovascular disease. Remember that it is generally advisable to consult your doctor or dietician when deciding on a diet that is best for you and your condition. Lastly, keep in mind that as with any other food, moderation and balance is the key.

Last update: June 2021

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References

a The Food and Agriculture Organization and the World Health Organization

1 Carson, J., Lichtenstein, A. H., Anderson, C., Appel, L. J., Kris-Etherton, P. M., Meyer, K. A., Petersen, K., Polonsky, T., Van Horn, L., & … Council on Clinical Cardiology; Council on Peripheral Vascular Disease; and Stroke Council. (2020). Dietary Cholesterol and Cardiovascular Risk: A Science Advisory From the American Heart Association. Circulation, 141(3), pp. e39–e53. doi:10.1161/CIR.0000000000000743

2 Drouin-Chartier, J. P., Chen, S., Li, Y., Schwab, A. L., Stampfer, M. J., Sacks, F. M., . . . Bhupathiraju, S. N. (2020). Egg consumption and risk of cardiovascular disease: three large prospective US cohort studies, systematic review, and updated meta-analysis. British Medical Journal, 368, p. m513. doi:10.1136/bmj.m513

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3 Dehghan, M., Mente, A., Rangarajan, S., Mohan, V., Lear, S., Swaminathan, S., . . . Yusuf, S. (2020). Association of egg intake with blood lipids, cardiovascular disease, and mortality in 177,000 people in 50 countries. The American Journal of Clinical Nutrition, 4, pp. 795–803. doi:10.1093/ajcn/nqz348

4Krittanawong, C., Narasimhan, B., Wang, Z., Virk, H., Farrell, A. M., Zhang, H., & Tang, W. (2021). Association Between Egg Consumption and Risk of Cardiovascular Outcomes: A Systematic Review and Meta-Analysis. The American Journal of Medicine, 1, pp. 76–83.e2. doi:10.1016/j.amjmed.2020.05.046

5 Zhuang, P., Wu, F., Mao, L., Zhu, F., Zhang, Y., Chen, X., . . . Zhang, Y. (2021). Egg and cholesterol consumption and mortality from cardiovascular and different causes in the United States: A population-based cohort study. PLOS Medicine, 2, p. e1003508. doi:10.1371/journal.pmed.1003508

6 British Heart Foundation. (2021). Do eggs raise your risk of heart disease and death? Retrieved June 2021, from https://www.bhf.org.uk/informationsupport/heart-matters-magazine/news/behind-the-headlines/egg-risks

7 European Food Information Council. (2021). In the news: Will eating 3 eggs a week increase your risk of dying young? Retrieved June 2021, from https://www.eufic.org/en/newsroom/article/in-the-news-will-eating-3-eggs-a-week-increase-your-risk-of-dying-young

8 Jacobson, T. A., Maki, K. C., Orringer, C. E., Jones, P. H., Kris-Etherton, P., Sikand, G., La Forge, R., Daniels, S. R., Wilson, D. P., Morris, P. B., Wild, R. A., Grundy, S. M., Daviglus, M., Ferdinand, K. C., Vijayaraghavan, K., … NLA Expert Panel. (2015). National Lipid Association Recommendations for Patient-Centered Management of Dyslipidemia: Part 2. Journal of Clinical Lipidology, 9(6 Suppl), pp. S1–122.e1. doi:10.1016/j.jacl.2015.09.002

9 Mach, F., Baigent, C., Catapano, A. L., Koskinas, K. C., Casula, M., Badimon, L., Chapman, M. J., De Backer, G. G., Delgado, V., Ference, B. A., Graham, I. M., Halliday, A., Landmesser, U., Mihaylova, B., Pedersen, T. R., … ESC Scientific Document Group. (2020). 2019 ESC/EAS Guidelines for the management of dyslipidaemias: lipid modification to reduce cardiovascular risk. European Heart Journal, 41(1), pp. 111–188. doi:10.1093/eurheartj/ehz455

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11 U.S. Department of Health and Human Services and U.S. Department of Agriculture. (2020). Dietary Guidelines for Americans, 2020-2025. 9th Edition. Retrieved June 2021, from https://www.dietaryguidelines.gov/resources/2020-2025-dietary-guidelines-online-materials

12 European Food Safety Authority. (2010). Scientific Opinion on Dietary Reference Values for fats, including saturated fatty acids, polyunsaturated fatty acids, monounsaturated fatty acids, trans fatty acids, and cholesterol. EFSA Journal, 8(3), 1461. doi:10.2903/j.efsa.2010.1461

13 Public Health England. (2016). Government Dietary Recommendations: Government recommendations for energy and nutrients for males and females aged 1 – 18 años and 19+ años. Retrieved from https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/618167/government_dietary_recommendations.pdf

14 Health Canada, Government of Canada. (n.d.). Dietary Reference Intakes Tables (last updated: 2010). Retrieved June 2021, from https://www.canada.ca/en/health-canada/services/food-nutrition/healthy-eating/dietary-reference-intakes/tables.html#rvm

15 National Health and Medical Research Council, Australian Government Department of Health and Ageing, New Zealand Ministry of Health. (2006). Nutrient Reference Values for Australia and New Zealand Including Recommended Dietary Intakes (last updated: 2017). Retrieved from https://www.nhmrc.gov.au/about-us/publications/nutrient-reference-values-australia-and-new-zealand-including-recommended-dietary-intakes#block-views-block-file-attachments-content-block-1

16 National Health Commission of the People’s Republic of China. (2017). Dietary Reference Intakes for Chinese Residents, Part 1: Macronutrients (中国居民膳食营养素参考摄入量第1部分:宏量营养素). Retrieved from http://www.nhc.gov.cn/wjw/yingyang/201710/fdade20feb8144ba921b412944ffb779.shtml

17 Health Promotion Administration, Taiwan Ministry of Health and Welfare. (2020). Dietary Reference Intakes Eighth Edition: Macronutrients Protein and lipid chapter (draft) revision (「國人膳食營養素參考攝取量」第八版-巨量營養素: 蛋白質及脂質章節(草案)增修訂 線上說明會之重點紀要). Retrieved June 2021, from https://www.hpa.gov.tw/Pages/List.aspx?nodeid=4247

18 World Health Organization & Food and Agriculture Organization of the United Nations. (1994). Fats and oils in human nutrition: Report of a Joint FAO/WHO Expert Consultation. Rome. Retrieved from https://www.who.int/nutrition/publications/nutrientrequirements/9251036217/en/

19 U.S. Department of Health and Human Services and U.S. Department of Agriculture. (2010). Dietary Guidelines for Americans 2010. 7th Edition. Retrieved June 2021, from https://health.gov/our-work/food-nutrition/previous-dietary-guidelines/2010

20 U.S. Department of Health and Human Services and U.S. Department of Agriculture. (2015). 2015 – 2020 Dietary Guidelines for Americans. 8th Edition. Retrieved June 2021, from https://health.gov/our-work/food-nutrition/previous-dietary-guidelines/2015

21 Ministry of Health, Labour and Welfare, Government of Japan. (2020). Dietary Reference Intakes for Japanese (2020): Report of the Study Group on the Dietary Reference Intakes for Japanese People (日本人の食事摂取基準(2020 年版): 「日本人の食事摂取基準」策定検討会報告書). Retrieved from https://www.mhlw.go.jp/stf/newpage_08517.html

22 Fujioka, Y. (2018). Diet therapy in Japan Atherosclerosis Society (JAS) Guidelines for Preventing Atherosclerotic Cardiovascular Disease 2017 (動脈硬化性疾患予防ガイドライン2017における食事療法). Journal of the Japanese Coronary Association, 24(1), pp. 20-25. doi:10.7793/jcoron.24.003

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24 National Institute for Health and Care Excellence. (2014). Clinical guideline [CG181]: Cardiovascular disease: risk assessment and reduction, including lipid modification (last updated: 2016). Retrieved from https://www.nice.org.uk/guidance/cg181

25 Heart UK. (n.d.). High cholesterol food. Retrieved June 2021, from https://www.heartuk.org.uk/low-cholesterol-foods/foods-that-contain-cholesterol

26 U.S. Department of Agriculture (USDA). (2020). FoodData Central: Egg, whole, raw. Retrieved June 2021, from https://fdc.nal.usda.gov/fdc-app.html#/food-details/1100183/nutrients

27 Agence nationale de sécurité sanitaire de l’alimentation, de l’environnement et du travail (Anses), France. (2020). Ciqual – Table de composition nutritionnelle des aliments: Oeuf, cru. Retrieved June 2021, from https://ciqual.anses.fr/#/aliments/22000/oeuf-cru

28 National Heart Foundation of Australia. (2019). Eggs & Cardiovascular Health: Summary of Evidence. Retrieved June 2021, from https://www.heartfoundation.org.au/health-professional-tools/Nutrition-Evidence-Summaries-and-Reviews

29 National Heart Foundation of New Zealand. (2016). Eggs and the Heart: Evidence Paper. Retrieved June 2021, from https://www.heartfoundation.org.nz/resources/eggs-and-the-heart-evidence-paper

30 Chinese Nutrition Society. (2016). Dietary Guidelines for Chinese Residents 2016 (中国居民膳食指南 2016). Retrieved June 2021, from http://dg.cnsoc.org/article/2016b.html

31 Health Promotion Administration, Taiwan Ministry of Health and Welfare. (2018). Daily Food Guide Booklet (每日飲食指南手冊). Retrieved June 2021, from https://www.hpa.gov.tw/Pages/EBook.aspx?nodeid=1208

32 Arnett, D. K., Blumenthal, R. S., Albert, M. A., Buroker, A. B., Goldberger, Z. D., Hahn, E. J., . . . Ziaeian, B. (2019). 2019 ACC/AHA Guideline on the Primary Prevention of Cardiovascular Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation, 140(11), pp. e596–e646. doi:10.1161/CIR.0000000000000678

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