Egg whites: all the essential amino acids you need!
There’s an awful lot of talk about proteins in the healthy diet world. How do you make sure you’re getting enough, how much is enough and can you get enough protein if you don’t eat meat?
But to understand all of that, we need to first understand what protein is made of. Amino acids are the building blocks of proteins and there are 20 different amino acids – each different type of protein in the human body is made up of a different amount and combination of these 20 amino acids.
The body can manufacture 11 of the amino acids, and they’re considered ‘non-essential’ amino acids because it isn’t essential that we consume them in our diets. The other nine amino acids are considered essential, because we cannot get them from anywhere aside from our diet.
Foods that contain all nine essential amino acids are known as ‘complete protein’ foods and tend to be animal-based foods such as meat, dairy products and eggs. (It’s also possible to get all nine essential amino acids from plant-based foods such as peas and beans, but it might require some extra thought.)
Egg whites are a naturally occurring complete protein with all nine essential amino acids, and contain, on average, around 3.4 grams of protein per egg white. Around 40% of the protein content of an egg white is made up of the essential amino acids.
It’s for this reason that many nutritionists consider eggs to be one of the healthiest foods around and eating them regularly can help us make sure we’re getting enough protein to meet our needs, whilst not overgoing it on the calories, since egg whites are low in calories and fat, and despite the rumours of the 1990s, are also low in cholesterol (more on that later).
The importance of protein
The human body contains thousands of different proteins, and they’re found in everything from our muscles to our cells to our hair and nails. Each protein is constantly being broken down and replaced by newly made proteins.
When a protein is broken down, it releases its amino acids, some of which can be used to make new proteins, but others become oxidised and therefore cannot be used, so it’s essential that we eat enough.
The nine essential amino acids are as follows:
Egg whites contain all of these, as well as some of the non-essential amino acids, making egg whites an extremely nutritious food.
The quality of protein in egg whites
There is a system, called the Digestible Indispensable Amino Acid Score (DIAAS), developed by the Food and Agricultural department of the World Health Organisation (WHO), that is an internationally recognised way of scoring and grading the protein quality of foods.
The DIAAS score of a food depends on how many essential amino acids it contains compared to non-essential and how well the body can digest them.
Egg whites are around 93% protein and contain mainly the protein albumin. Albumin has one of the highest DIAAS scores of all foods due to its availability of essential amino acids. The amino acid profile of egg whites is as close to a perfect match for amino acid requirements as is possible.
As well as the essential amino acids, egg whites contain some of the non-essential amino acids, so consuming them regularly can mean that we’re preventing a protein deficiency and looking after our health and wellbeing.
Egg whites contain the following non-essential amino acids as well as all nine essential amino acids:
- Aspartic acid
- Glutamic acid
Why do we need protein?
As we mentioned above, the body needs protein from our diet for healthy cells, muscles, hair and nails, as well as for important functions such as building new proteins and tissues, to helping us meet our energy requirements, regulating our appetite and helping us recover from injury.
We also require amino acids to help us regulate our mood and they can help to reduce the symptoms of anxiety and depression. Some amino acids also help to keep the blood vessels healthy by reducing plaque build-up and for stimulating the production of collagen that we need for youthful skin and healthy wound healing.
Another benefit of the essential amino acid content of egg whites is that they contain the three branched chain amino acids (BCAA) that help to build lean muscle mass.
The nutritional benefits of egg whites
The number of calories in egg whites is very low compared to their high protein content and they’re free from saturated fat, cholesterol, carbohydrates and sugar. This makes them super healthy, especially if you’re on a calorie controlled diet or you have diabetes or heart disease.
Egg whites are also rich in vitamin B2 (also known as riboflavin) and the mineral potassium. We need vitamin B2 to help release the energy from the carbohydrates in our food which in turn can help to speed up our metabolism. More than 60% of the vitamin B2 in eggs is found in the egg white.
Potassium is essential for heart health by helping to keep the blood vessels open and vasodilated. This in turn helps to lower blood pressure, helping to keep the heart pumping as it should and the blood flow healthy.
The whites of an egg also contain a relatively recently understood compound called RVPSL. RVPSL can lower blood pressure with results equivalent to the blood pressure lowering drug Captopril by blocking the effects of angiotensin converting enzymes that can increase blood pressure.
Egg whites are also extremely versatile, and can be used in many recipes from omelettes and savoury muffins and frittatas to meringues and macarons. Since they’re so high in protein and low in calories, they’re popular with those who exercise a lot to help build lean muscle mass. Such high protein foods also help to keep us feeling fuller for longer and sustain energy levels, which can help with weight loss.
Studies also show that eating a high protein breakfast, for example one that contains egg whites, helps to dampen down our insulin and glucose responses after eating, meaning lower blood sugar levels and less risk of energy spikes and dips. This means that we’re less likely to overeat at our next meal as we’ll already be feeling fuller.