All about eggs, eggs cholesterol and how many eggs can I eat a day?
Despite the fact that eating eggs was so common in our diet in ancient times, and in almost all cultures it has been appreciated for being easy to obtain, cheap and for its high nutritional content of easy absorption, with a wide use within the food industry.
Its consumption was contraindicated by health professionals in the 60s, since it was thought that eggs cholesterol raised blood cholesterol, and increased the chances of suffering from cardiovascular diseases.
Later it was found that reducing dietary cholesterol did not lead to a significant reduction in plasma cholesterol levels (6, 10), or to a lower incidence of cardiovascular disease (2, 10). This fact makes us to change or way of thought about the role of cholesterol in the diet. Since now we know that our body has a more complex cholesterol regulation (homeostasis) mechanism than just eating less cholesterol (1, 2, 7, 10).
Cholesterol functions.
Our body needs a continuous supply of cholesterol, since it performs many functions in the body:
- It is an essential component of cell membranes, including myelin in our nervous system.
- It is a precursor of steroid hormones necessary for our sexual, reproductive and general health.
- It is a precursor of bile acids necessary for fat digestion.
- It is a precursor of vitamin D.
Regulation of cholesterol by our body.
Cholesterol is synthesized in most tissues with red blood cells exception, but the main place is the liver, in simple words our body cholesterol regulation mechanism works like this: if you increase your dietary cholesterol intake, your liver produces less, if you eat less cholesterol in your diet, the liver produces more (1, 7 , 10, 11, 12).
It is also true that there are people with hypersensitivity to dietary cholesterol, in which case dietary intake of cholesterol does increase blood cholesterol, but it is a very small group of the population (1).
Eggs and its cholesterol.
In fact, the slight increase in total cholesterol that happens by increasing egg intake is primarily HDL, protective against coronary heart disease (1, 4, 7, 8, 9, 10, 11). In addition to all this, keep in mind that egg yolk contains lecithin and other substances that prevent a significant absorption of cholesterol by our intestines (1, 3).
Even the American Heart Association in its latest guide includes eggs as part of a healthy diet and eliminates the 300mg/day limit for cholesterol in its guide, which had been around since 1968. And although it still limits the number of eggs to 1 daily (10, 11), progress is gradually made in nutrition.
Nutritional content of eggs:
- It is the best source of natural protein, the one with the highest biological value and best net use of protein, only beaten by isolated protein supplements, such as whey protein.
- They are low in saturated fat compared to other animal proteins.
- Rich in vitamins A, D, E, K, B2, B5, B12 and minerals iron, zinc, iodine, phosphorus, potassium, selenium.
- Egg yolk is a good source of carotenoids such as lutein and zeaxanthin, antioxidants that are very important in visual health, and helps prevent macular degeneration and cataracts.
- Excellent source of choline, a fundamental nutrient for the brain, liver and muscles, a large egg (60g) provides approximately 30% of the daily requirements.
- Low in calories. an egg has only 70-80 calories.
- It does not increase blood cholesterol, in fact, the slight increase in total cholesterol that happens when we increase the intake of eggs is mainly HDL, protective against coronary disease
- Source of Omega 3, depending of the hen diet.
- They are satisfying. Starting the morning with two eggs makes you eat less during the day, which helps you lose weight.
Variation of the nutritional composition of eggs
Eggs nutritional composition can vary depending on the hens, the rearing method and their diet (3). So, it is always advisable to choose organic eggs or eggs of free-range chickens (happy chickens) and avoid eggs from hens raised in cages (sad chickens). Since depending on the diet and the stress that hens suffer with the rearing methods, the fats, minerals and fat-soluble vitamins of eggs vary.
How many eggs can I eat a day?
However, there are people who include more than 3 eggs in their diet and their health and blood tests are perfect.
For example, If you are a high-performance athlete such as a high mountain cyclist of 202Lb, who does routes of 20 miles a day in competition periods, 3 eggs may be too few for you. If, on the other hand, you are an enthusiastic athlete with a low or medium performance of 120Lb, 2 eggs may be enough.
There is even a study of a person who eat 25 eggs a day and his blood tests and health were perfectly fine (5), I never recommend excesses, not even with the best food, because like Paracelso said ¨the dose makes the poison¨ and as with any food, there may be problems with its abuse, but limiting a healthy food by old and questionable hypotheses is absurd.
Egg whites or egg yolk? Which is better?
Egg is a great food. However, much of its nutritional properties are found in egg yolk, not in egg whites. Most vitamins and all carotenoids are in egg yolk as well as almost half of its proteins (3).
If you eliminate egg yolk not only do you lose that protein, vitamins and carotenoids, but you also decrease the quality of total protein, turning it into a protein of lower biological value. Since the protein from the whole egg generates greater protein synthesis than the protein from egg whites alone. Without considering food waste. It is best to eat the whole egg.
Raw or cooked?
Humans start cooking to improve the digestibility of our food, since heat enhances the absorption of certain nutrients, although it also interferes with the absorption of others.
Cooking degrades some heat sensitive vitamins, but also improves protein digestibility and the absorption of biotin or vitamin B8 in eggs.
Since heat inhibits the anti-vitamin avidin that interferes with its absorption present in eggs whites (3), in the same way when we cook, we eliminate dangerous bacteria such as salmonella.
Because all of this, it is advisable to cook our eggs. If you like it to add them to your post-workout shake, I recommend you adding them already cooked in the blender and then blending them to make your shake.
Are our eggs fresh?
If you have any doubts about an egg state, put it in water:
- If it sinks, you can eat it.
- If it rises from the bottom, without floating, it is good, but it has little time left.
- If it floats, it is bad.
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Now you know, eggs are an excellent food, next time someone tells you that you should not eat so many eggs, because they are bad and raise blood cholesterol, show them this article that one by one we will be able to change the bad reputation of eggs.
Referencies
1. Blesso, C, & Fernandez, M. (2018). Dietary Cholesterol, Serum Lipids, and Heart Disease: Are Eggs Working for or Against You? Nutrients, 1-12.
2. Griffin, B. A. (2016). Eggs: good or bad? Conference on ‘The future of animal products in the human diet: health and environmental concerns’ Symposium 2: Milk and eggs, health and sustainability (págs. 259–264). Nottingham: The Nutrition Society Summer Meeting.
3. Hernandez, A. G. (2010). Tratado de Nutrición Tomo II Composición y Calidad Nutritiva de los Alimentos. Madrid:: Editorial Médica Panamericana.
4. Joseph, R, Mutungi, G, Puglisi, M, Volek, J, & Fernandez, M. (2008). Eggs modulate the inflammatory response to carbohydrate restricted diets in overweight men. Nutrition & Metabolism.
5. Kern, F. (1991). Normal plasma cholesterol in an 88-year-old man who eats 25 eggs a day. The new england journal of medicine, 896-899.
6. Keys, A, Anderson, J, & Grande, F. (1965). Serum Cholesterol Response to Changes in the Diet II. The Effect of Cholesterol in the Diet. Metabolism, 750-765.
7. Lemos, B, Medina, I, Blesso, C, & Fernandez, M. (2018). Intake of 3 Eggs per Day When Compared to a Choline Bitartrate Supplement, Downregulates Cholesterol Synthesis without Changing the LDL/HDL Ratio. Nutrients, 1-12.
8. Mutungi, G, Ratliff, J, Puglisi, M, Torres, M, Vaishnav, U, Leite, J, Fernandez, M. (2008). Dietary Cholesterol from Eggs Increases Plasma HDL Cholesterol in Overweight Men Consuming a Carbohydrate-Restricted Diet. The Journal of Nutrition, 272-276.
9. Pearce, K, Clifton, P, & Noakes, M. (2011). Egg consumption as part of an energy-restricted high-protein diet improves blood lipid and blood glucose profiles in individuals with type 2 diabetes. British Journal of Nutrition, 584–592.
10. Soliman, G. (2018). Dietary Cholesterol and the Lack of Evidence in Cardiovascular Disease. Nutrients, 1-14.
11. Xia, P.-F, Pan, X.-F, Chen, C, Wang, Y, Ye, Y, & Pan, A. (2020). Dietary Intakes of Eggs and Cholesterol in Relation to All-Cause Mortality: A Prospective Cohort Study. Journal of the American Heart Association, 1-11.
12, Yeon Lim, M, Benyon, S, & O´Neale Roach, J. (2013). Lo esencial en el metabolismo y nutrición. Barcelona: Elsavier.
