Healthy eggs: The difference between eggs

In the supermarket you can find many different types of eggs, such as grass eggs, corn eggs, four-grain eggs, free-range eggs, round eggs, organic eggs, omega-3 eggs and double-yolk eggs. These special eggs are usually sold for a higher price than the standard cheaper free-range eggs. The offer is large, but what is the difference between these eggs? How do the chicken's food and conditions affect the egg it lays?

Eggs

In the Netherlands, we eat about two hundred chicken eggs a year. Most eggs are bought in the supermarket, a specialty store or from the farmer. These eggs are largely laid by Dutch hens. A hen has about two thousand egg yolks available at birth to make eggs from during her lifetime. A good laying hen lays about three hundred eggs a year during her first years of life. After the first two years, the hen will lay less and less eggs. The eggs of older hens are getting bigger, but also of less quality. For this reason, hens older than two years are slaughtered in the industry.

It takes about twenty-five hours for an egg to be ready to be laid. During this process, the egg is formed in the hen's fallopian tube. The yolk is formed from the eggs that have been present from birth. When the yolk is ready, an egg settles in the yolk and the yolk is released into the ovaries. This is the beginning of an egg's development. The yolk is provided with a membrane and strings of sprinkles, so that the yolk later stays in place in the egg. The yolk is then coated in the fallopian tube with several layers of egg white. This protein is surrounded by a membrane that holds the egg together. When this is done the eggshell is formed. The latter process takes the longest, at least twenty hours. When the eggshell is ready, the egg is ready to be laid.

Eggs consist of one third egg yolk and two thirds egg white. The egg yolk contains all the nutrients for the chick. The yolk therefore contains most of the nutrients of the egg. Most of an egg is made up of egg white. This serves to protect the chick. Protein therefore consists mainly of water and a small part of proteins. Finally, an egg is surrounded by a membrane and an eggshell. These serve to protect the egg. The eggshell contains a lot of calcium and can also be eaten. However, it is not considered very tasty and therefore not often eaten by people.

Eggs contain a lot of proteins, fats, vitamins and minerals. These nutrients are mainly in the egg yolk. Eggs weigh about 50 to 70 grams each, an egg yolk weighs about 15 to 20 grams each. The nutritional value of eggs is shown in the table below.

The fats come from the egg yolk, the egg white contains hardly any fat. The fat in the yolk consists mainly of unsaturated fats. Unsaturated fats are good fats that can lower the risk of cardiovascular disease. The monounsaturated fats make up the majority of the fatty acids in eggs. In addition, it contains a part of polyunsaturated fatty acids, of which the ratio of omega-3 and omega-6 fatty acids is approximately 1 to 7. Linoleic acid, an essential omega-6 fatty acid, lowers blood cholesterol. However, in large amounts they can promote inflammatory reactions. The Dutch consume on average about three times as much linoleic acid as recommended. Shortages are therefore almost non-existent. The omega-3 fatty acid linolenic acid is anti-inflammatory. The ideal ratio of omega-3 to omega-6 fatty acids in the diet is about 1 to 4, but in most Western diets this ratio is 1 to 15 to 1 to 20. So the ratio of 1 to 7 in eggs is not ideal, but compared to the ratio in western food, it is not bad. In addition, eggs mainly contain EPA as an omega-3 fatty acid. This is better than the more common omega-3 fatty acid ALA, because the latter fatty acid must first be converted into the essential fatty acid EPA, which is inefficient.

Eggs are a good source of protein. The amount of protein in the egg yolk is greater per 100 grams, but because an egg consists of two-thirds of protein, most of the proteins come from the egg white. The proteins can best be absorbed by the body when the eggs are cooked. Raw eggs therefore contain less nutritional value than boiled eggs.

Eggs contain a lot of vitamin B12 and vitamin D. Vitamin D in particular is found in very few foods, so that many people do not get enough of it. An egg already contains about 20 percent of the recommended amount of vitamin D. Eggs also contain important minerals such as phosphorus, selenium, iron and zinc.

Eggs contain a lot of cholesterol. The cholesterol comes from the egg yolk. An egg yolk contains about two-thirds of the maximum recommended amount of cholesterol. In the past, it was therefore recommended not to eat more than two eggs per week. However, this advice is outdated, because research has shown that eating eggs does not increase blood cholesterol. The body can compensate for the higher intake of cholesterol from food by making less cholesterol itself. In addition, the omega-6 fatty acids from eggs reduce bad cholesterol in the blood.

Eggs can have different quality marks, such as the EKO, Grass quality mark and Beter Leven quality marks. These quality marks say something about the welfare of the chickens. For example, they set requirements for the feed that the chickens receive and the amount of space that must be reserved per chicken. In general, the requirements for the EKO quality mark are the strictest. These are organic eggs where the feed for the chickens is largely organic. The chickens also have more space and no chemical pesticides are used.

Besides the quality mark, there is also a difference about how the chickens are kept. This is also called a husbandry system. This can be recognized by the code stamped on the egg. The code 0 stands for organic, 1 stands for free-range, 2 stands for free-range and code 3 is cage eggs.

An egg can in some cases become healthier if the conditions of the chicken change.

By adjusting the feed, the fatty acid composition can change slightly. The chickens then get a special diet in which the saturated fatty acids are limited and which is rich in unsaturated fatty acids. In such a diet, the chickens are fed vegetables rich in omega-3 fatty acids, such as purslane. The feed can also be enriched with omega-3 fatty acids. These omega-3 fatty acids then mainly end up in the eggs in the form of EPA. This allows the eggs to contain up to twenty times more omega-3 fatty acids, making the ratio of omega 3 and omega 6 optimal.

When chickens can find their own food, it is often the case that they eat more green. If the chickens have a choice of rich omega-3 sources, free-range or organic eggs will be healthier. However, this is not always the case. As a result, organic or free-range eggs are in practice no healthier than cage or free-range eggs. In fact, chickens that forage outside can more quickly absorb contaminants from the ground that end up in the eggs. This can contaminate the eggs with dioxins and heavy metals.

Chickens that eat a lot of corn often have a dark yellow yolk because corn contains a lot of carotene, a type of vitamin A. However, the eggs hardly contain any more vitamin A, only the color of carotene. As a result, corn eggs are not healthier. Four-grain eggs aren't healthier either. It turns out that the eggs of a chicken are fairly constant in composition and that the feed has little influence on the composition of the egg. An exception therefore applies only to omega-3 eggs, which can be healthier than eggs from chickens that have only been fed grains.