Nutrition Focus: The Humble Egg

However you like them - scrambled, poached, fried or added to an omelette - eggs are a delicious, nutrient-dense food, providing a variety of essential nutrients that play crucial roles in maintaining overall health. You would be hard pressed to find a food that contains such an ideal mixture of nutrients.

Modified or enriched eggs are those in which the content has been modified from the standard eggs. The vitamin and trace mineral enrichment of eggs can be achieved by manipulating the diet of laying hens, as is seen in St. Ewe Super Eggs. Eggs enriched with certain trace minerals, vitamins and a variety of bioactive substances can be an excellent source of these substances in human diets.

Enriched or not, eggs are nutritional powerhouses that play a huge role in the diets of the British population. On average, 11 billion eggs are laid by hens in the UK each year, making the UK 86% self-sufficient in egg production. We eat over 12 billion eggs in the UK every year – if these were placed all in a line they would go round the world 17 times! It is estimated that per consumer, we eat 200 eggs each per year. The UK egg industry is worth over £1 billion to the UK economy and provides 13,000 jobs. 

Here is a breakdown of the nutritional value of an average egg, highlighting key nutrients and their roles:

Protein

Eggs are a complete protein source, meaning they contain all nine essential amino acids required by the body: histidine, isoleucine, leucine, methionine, phenylalanine, threonine, tryptophan and valine. Eggs are considered one of the highest quality forms of protein ahead of cow’s milk and beef, and have a significantly lower contribution to greenhouse gas (GHG) emissions. Making a switch from meat to eggs may be a helpful dietary shift that is of benefit to the environment while still providing you with the protein you need.

 Fats

Around 9% of the egg content is fat. The fat of an egg is found almost entirely in the yolk; there is less than 0.5% in the albumen. Most of an egg’s total fatty acid composition is monounsaturated (approximately 38%). About a further 16% is polyunsaturated and only 28% is saturated.

Monounsaturated Fats:

  • Monounsaturated fats in eggs, such as oleic acid, play a role in promoting heart health by improving cholesterol levels. These fats contribute to a balanced lipid profile, lowering LDL ("bad") cholesterol while increasing HDL ("good") cholesterol. Additionally, monounsaturated fats possess anti-inflammatory properties and support overall cardiovascular well-being. 

Polyunsaturated Fats:

  • Polyunsaturated fats in eggs, specifically omega-3 and omega-6 fatty acids, play a key role in supporting cardiovascular health by reducing blood clotting and inflammation. These essential fats are vital for proper brain function and development, contributing to cognitive well-being. Additionally, polyunsaturated fats in eggs are associated with maintaining healthy skin, hair, and cell membranes.

Cholesterol Debate

What is Cholesterol?

Cholesterol, a fat-like, waxy substance, is found in all cells of our bodies, playing a key role in creating hormones, vitamin D, and certain substances that aid digestion. It's worth noting that our bodies produce all the cholesterol we need, primarily in the liver. However, we also obtain cholesterol through our diet, specifically from animal-based foods such as egg yolks, meat, and cheese.


Eggs and Cholesterol:

Eggs are naturally high in cholesterol. But the cholesterol in eggs doesn't seem to raise cholesterol levels the way some other foods do, such as those high in saturated fats. Most healthy people can eat up to seven eggs a week without increasing their risk of heart disease. Some studies have shown that egg consumption might even help prevent certain types of stroke and a serious eye condition called macular degeneration that can lead to blindness.

Vitamins in the average egg

It’s important to note that these figures will vary depending on egg enrichment and fortification of the hens diets. 


Vitamin B12:

  • Role: B12 plays a crucial role in the formation of red blood cells, aiding in the prevention of anaemia and promoting optimal oxygen transport. Vitamin B12 is also necessary for maintaining a healthy nervous system, as it contributes to the production of myelin, the protective covering of nerves. Additionally, B12 supports DNA synthesis and cell division, crucial for growth and development. 

  • Amount: About 1.4 micrograms per egg.

Vitamin A:

  • Role: Vitamin A plays a crucial role in maintaining healthy vision and supporting the function of the retina and promoting low-light vision. Additionally, vitamin A is essential for immune system function, helping the body combat infections and illnesses. It contributes to skin health, supporting the growth and maintenance of epithelial tissues, is crucial for proper cell differentiation and plays a role in reproduction. 

  • Amount: Around 64 micrograms in the form of retinol activity equivalents (RAE) per egg.

Vitamin D:

  • Role: Its primary function is to regulate calcium and phosphorus absorption, supporting the development and maintenance of strong and healthy bones. Vitamin D is also pivotal for a well-functioning immune system, helping the body defend against infections and illnesses. Beyond skeletal health, adequate levels of vitamin D have been linked to a lower risk of chronic diseases, including cardiovascular conditions, and are associated with mood regulation, potentially impacting mental well-being.

  • Amount: Approximately 1.6  micrograms per egg.

Minerals in the average egg

It’s important to note that these figures will vary depending on egg enrichment and fortification of the hens diets.

Phosphorus:

  • Role: Primarily known for its role in skeletal health and the formation of strong bones and teeth, it also plays a crucial part in various physiological processes, including energy metabolism through its involvement in ATP (adenosine triphosphate) production. Phosphorus is also essential for cell structure, DNA and RNA synthesis, and the regulation of acid-base balance in the body. Additionally, this vital mineral contributes to the activation of enzymes and is a key component of important molecules such as phospholipids, which are integral to cell membranes.

  • Amount: Around 91 milligrams per egg.

Selenium:

  • Role: One of its primary functions is as a cofactor for antioxidant enzymes, including glutathione peroxidases, which help protect cells from oxidative damage. Selenium also supports a healthy immune system by influencing the production and function of immune cells. Furthermore, it is involved in thyroid hormone metabolism, contributing to the proper functioning of the thyroid gland. Adequate selenium intake is crucial for reproductive health, as it is integral to sperm development and maturation. 

  • Amount: Approximately 12 micrograms per egg.

Choline:

  • Role: Choline is a vital nutrient crucial for cell membrane structure, neurotransmitter synthesis (acetylcholine), and lipid metabolism. It plays a key role in liver health by aiding in the formation of very low-density lipoproteins (VLDL). Especially important during periods of growth and development, choline is essential for foetal brain development, supports DNA synthesis, and contributes to overall cellular communication and cardiovascular health.

  • Amount: About 145 milligrams per egg.

Zinc:

  • Role: Zinc plays an important role in promoting immune system function, aiding in wound healing, and contributing to DNA synthesis and cell division. Additionally, zinc is vital for optimal growth and development, supports sensory functions such as taste and smell, and participates in the regulation of gene expression.

  • Amount: One large egg contains about 0.6 milligrams of zinc.

Lutein and Zeaxanthin:

  • Role: Lutein and Zeaxanthin are antioxidants that promote eye health and may reduce the risk of age-related macular degeneration.

  • Amount: Varies, but roughly 186 micrograms of lutein and zeaxanthin per egg.

Omega-3 Fatty Acids:

  • Role: Omega-3 fatty acids in eggs, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are valuable for promoting heart health and supporting cognitive function. These essential fats contribute to maintaining healthy cell membranes and have anti-inflammatory properties. 

  • Amount: The content can be increased in eggs from hens fed a diet rich in omega-3 fatty acids.

Other minerals found in eggs include folate, biotin, iodine, chromium, calcium, copper, manganese and potassium. 

Vitamin D Focus: Cooking Method Study

Vitamin D is a crucial micronutrient involved in many bodily processes, from bone and teeth mineralisation to mood regulation. This vitamin is particularly difficult to get from food sources, as only a small number of foods contain limited amounts, one of which being enriched eggs. Given that over 90% of the British population does not consume adequate dietary vitamin D, enriched eggs, such as St. Ewe Super Eggs eggs present a viable source. 

Our main source of vitamin D comes from sunlight, as our skin can synthesise this vitamin naturally from UVB rays. During autumn, winter, and sometimes spring, when sunlight is scarce, the importance of supplementing with 10 mcg of vitamin D daily intensifies as we are less likely to obtain it from natural sources. 

However, a new study investigating the effects of storage and cooking methods on vitamin D retention in eggs. In this study, after storing and cooking the eggs using various methods, the eggs were freeze dried and tested for vitamin D3 and 25-Hydroxyvitamin D3 levels. The study measured the “true retention” of vitamin D, indicating the percentage of vitamin D preserved in the cooked product compared to its original amount before cooking. This took into account the different rates of weight loss from cooking, often due to water evaporation, with retention rates varying between 78% and 109%.

The study found that, after storing at room temperature, the methods of cooking that best preserved vitamin D, from most to least effective, were:

  • Scrambled Eggs (109%)

  • Microwaved Eggs (109%)

  • Poached Eggs (93%) 

  • Hard boiled eggs (80%)

  • Fried Eggs (78%)

When comparing vitamin-D enriched eggs to standard eggs, the enriched ones had vitamin D levels 22% to 132% higher, depending on the cooking method used.

Egg Labelling


Look for information on the packaging for more information about egg welfare. In the US, there will be information from USDA Organic or other animal welfare organisations to make sure that the eggs meet human and environmental standards. In the UK, the red lion mark shows that the egg meets regulated standards and is safe to eat. The British Lion scheme has been responsible for a drastic reduction to the presence of salmonella in UK eggs and the Food Standards Agency has recently confirmed that they are approved to be consumed runny, or even raw, by vulnerable groups.

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