The secret powers of egg yolk
When considering the benefits of raw eggs, what often springs to mind are bodybuilders trying to build muscle mass, or perhaps the urban legend of the raw egg hangover cure.
Health benefits of egg yolks
Egg yolks are a source of protein and are packed with nutrients, including iron, calcium, zinc, selenium, several B vitamins (B1, B2, B3, B6, folate, B12) ,vitamin A, vitamin K and vitamin E. They are one of the few foods that contain vitamin D and are a good source of healthy fats. They contain polyunsaturated and monounsaturated fats, including omega 3, an essential fatty acid that can only be sourced through the food you eat (or supplementation)¹.
Some of the key health benefits of including eggs in your diet are:
- they keep you fuller for longer due to high protein content,
- they make a great post workout snack to help muscles recover and grow,
- they contain choline, and essential nutrient for a healthy brain and nervous system,
- they contain the antioxidants lutein and zeaxanthin, which help maintain eye health,
- they contain peptides that have been shown to reduce blood pressure in rats,
- they contain sulfated glycoproteins, which support the immune system.
Cooked versus raw egg yolks
For many, the idea of eating raw egg yolks is off-putting, so why would you choose raw over cooked eggs?
Many nutrients are sensitive to heat and water, so when you cook foods, this can deplete the nutrients that you are getting in your diet. This isn’t always the case, and some nutrients require cooking to make them more digestible or available. For example, protein and biotin (vitamin B7).
Nutrients such as vitamin A, lutein, zeaxanthin and vitamin D are depleted when eggs are cooked. However, the nutrients in cooked eggs are easier for your body to digest and absorb. If you are eating a wholefood diet and eating a variety of foods, you should be getting most of the nutrients that you require.
Wholefoods are best eaten as a whole food, as nature designed them to provide a balanced and diverse source of nutrients. So, unless your recipe calls for just the yolk, or the white of an egg, or you have a particular health goal in mind, eggs are best eaten the way that nature intended.
Where nutrients are depleted due to heat, the general advice is to eat raw or to lightly cook the food. Of course, this advice is balanced with ensuring that you properly cook the food according to health and safety guidelines.
Raw egg yolks for immune health
Immunoglobulins are a type of antibody that protects you against pathogens, such as bacteria, viruses and fungi. Humans have five types of immunoglobulin, IgG, IgM, IgA, IgD and IgE. Each type of immunoglobulin has a different role, for example, IgE produces an immune response when you have an allergic reaction.
IgG is the main immunoglobulin found in the blood, lymph, cerebral spinal fluid and perineal fluid. This highly abundant antibody is the first responder when we have a bacterial or viral infection and protects you by remembering which pathogens you have been previously exposed to.
What does this have to do with raw egg yolk? Well, chickens also have immunoglobulins – natural glycoprotein isolate molecules, made up of a carbohydrate and a protein. Immunoglobulin Y (IgY) antibodies found in chicken yolk have been found to be almost identical to IgG found in mammals, playing a similar role of being the major immunoglobulins providing defence against infectious pathogens².
Egg yolks contain a high amount of IgY, but it is unlikely that we would be able to get adequate levels from our diet, because IgY is destroyed through the cooking process. In fact, to get the levels required to bolster your immunity, you would need to regularly consume raw egg yolk, which can be impractical and potentially unsafe.
The levels of immunoglobulins consumed from foods, such as eggs are safe. The structure of the IgY natural glycoprotein isolate means that it can be safely used at relatively high dosages, as an adjunct to your immune system, without compromising your immune health.
In supplement form, IgY begins working against pathogens in the gut where 70-80% of the immune system is found and in-so-doing takes the pressure off your immune system and frees vital resource up to deploy elsewhere in the body when its needed. Preliminary studies are starting to show how this supports immunity, respiratory health and sports performance³.
BBA (Hons)., BNat., mNMHNZ
Registered Naturopath & Medical Herbalist
¹ Batiha, G. E., et al. (2021). Dairy-derived and egg white proteins in enhancing immune system against COVID-19. Frontiers in Nutrition, 8. doi: 10.3389/fnut.2021.629440
² Warr, G. W., Magor, K. E., & Higgins, D. A. (1995). IgY: Clues to the origins of modern antibodies. Immunology Today, 16(8), 392-398. doi: 10.1016/0167-5699(95)80008-5
³ (n.d.). IGY Immune | For daily immune health. https://www.igyimmune.com/uploads/4/6/0/9/46096343/igy_life_sciences_-_summary_of_human_studies.pdf