Eggs...as good as gold?

[Lori Anne]

Egg yolk yellow,  the essence of all chicken life.  The essence of all life, in the egg.   Which came first, though you tell me.  And why, oh why, are my store bought run of the mill, previously barely-yellow egg yolks now bright as the sun, saffron coloured delicious orbs of gold?



Previously, store bought eggs were generally paler in comparison to farm fresh eggs, or brown chicken eggs.  Lately, even my cheapest. right off the grocers shelf are saffron coloured like the eggs from the best kept hens.  What gives?



I did some research to find out if farmers are now adding something to the chicken feed to make our yolks look so yellow and appealing and found some interesting information.

Here is some general info on the eggs we know and love to start our day with:

Hardly any other food is subject to such strict marketing guidelines as the egg. Eggs may only be offered to the consumer within the 21 days after they first saw the light of day. The "best before" date for fresh hen eggs is exactly 28 days after laying.

It’s an egg’s life…
Freshly laid eggs do not have a typical taste. The familiar attractive flavour only develops in the first three days after laying.

    * Day 1: laying date
    * Day 3: last packing date
    * Day 9: Up to day nine, eggs can be marketed with a sleeve marked "Extra" or "Extra Fresh". 
    * From day nine onwards, fresh eggs must be stored in a cool, dark and dry place.
    * Cooling date: after day 18, eggs must be kept in a refrigerator. 
    * From day 22 onwards: three-week-old eggs must be used quickly. They are no longer allowed to be offered for sale to the consumer at this age.
    * The "best before" date is passed on day 28.

So what makes our eggs so yellow?  How do they get their gorgeous golden colour?


Carotenoids – nature’s colorants
In 1931, the chemist Heinrich Wackenroder was the first to discover a carbon compound in carrots, naming it "carotene". We now know of some 650 carotenoids, without which natural life would be impossible. These substances are responsible, for example, for the yellow to reddish-orange colors of fruit and vegetables, for the vibrant hues of flowers and for many a colorful coat in the animal kingdom. Plants, fungi and bacteria around the world produce some three tons of carotenoids every single second.

In nature, carotenoids are much more than just colorants. They also perform vital protective and regulatory functions. Neither humans nor animals are capable of producing carotenoids themselves; we need to take them in with our food. Around fifty of these valuable colorants are important for humans as pro-vitamin A, meaning that they can be converted into vitamin A.


Carotenoids 

    * protect the cells of the body from harmful environmental influences (e.g. "free radicals")
    * improve the performance of the immune system
    * support detoxifying functions
    * are involved in the process by which we see
    * protect the skin from damage by ultra-violet light
    * increase the fertility of animals

 Carotenoids don’t just put color into egg yolks; they also perform vital functions. In the egg, they protect sensitive substances such as vitamins from becoming "rancid", and protect every single cell from harmful influences. Hens, too, profit from carotenoids in their feed: their immune systems are strengthened, protecting their cells from harmful environmental influences and providing the basis for vital vitamin A. When it comes to mother hen’s chicks, healthy birds only hatch if the yolks are provided with sufficient carotenoids. So yellow yolks are always a sign of happy hens.

One relatively new way for farmers to get more carotenoinds into hens in order to produce more golden coloured eggs is to supplement the hens feed with canthaxanthin.  Relatively unheard of, though still controversial, canthaxanthin is said to be safe for human consumption in small doses, however has been shown to cause several side effects.

[Lori Anne]

Scientists first discovered canthaxanthin, a common yellow carotenoid pigment, in edible chanterelle mushrooms. The chemical also occurs naturally in crustaceans, carp, green algae, Pacific salmon, and golden mullet. Considered a coloring agent and an antioxidant, canthaxanthin is approved by the United States Food and Drug Administration (FDA) as a food additive, in which case only minute amounts are employed.

Some tanning pills incorporate this pigment, which, when ingested, accumulates in the fat layer of the skin and produces a golden hue, simulating a tan. Although canthaxanthin theoretically increases skin resistance to ultraviolet light due to its antioxidant effects, the FDA does not approve the use of this product as a tanning agent or a medicine. The copious amount required to induce a skin-coloring effect has been linked to several side effects, including liver damage, aplastic anemia, and canthaxanthin retinopathy, an ocular condition in which yellow deposits collect in the retina.

Researchers have studied canthaxanthin for use in treating conditions that produce abnormally high levels of irritation and sensitivity to sunlight, including medication-induced photosensitivity, eczema, and erythropoietic protoporphyria, which is a genetic disorder. During the warmer months when patients most often receive more sun exposure, physicians prescribe between 60 to 90 milligrams of canthaxanthin each day. Patients typically use the pills three to five months each year.

Due to its chemical similarity and possible conversion to Vitamin A, patients with allergies to Vitamin A or carotenoids should not take this product. Canthaxanthin is soluble in fat and can be stored in the body for long periods of time. For this reason, as well as its unknown effect on a developing fetus, pregnant women and breast-feeding mothers should refrain from using these pills.


Canthaxanthin can produce unpleasant adverse reactions,
including diarrhea, nausea, stomach cramps, and reddish-orange body secretions. It may also lead to the development of an itchy, dry skin rash, known as urticaria, or hives in allergic individuals.


Aplastic anemia, a dangerous and potentially fatal condition in which the bone marrow fails to make new blood cells, can occur with the use of these carotenoid pills. Reported in 1989, tanning pill intake induces the reversible deposition of yellow crystals in the retina of the eye, associated with reduced ability of the light-sensitive cells to detect light at lower levels. Considering the potential for liver toxicity along with the other drawbacks of this additive, the FDA issued a health warning in 2003 to all companies that marketed products containing this chemical.


Canthaxanthin has come to media attention for its use in aquaculture, particularly salmon farming, in which it is used to give the salmon a more appealing color than the otherwise grey or pale yellow hue. It is also used in poultry farming to enhance the color of the skin of chickens and give egg yolks a richer color. In both cases, the pigment have would come from a source in the diet of the animal in the wild, however, in industrial farming, synthesized canthaxanthin is supplied in the feed.

In the United States, canthaxanthin is an FDA-approved food additive color. Its inclusion in chicken feed is regulated at a maximum of 4.41mg/kg of feed and need not be declared on labels of the end product. Its inclusion in fish feed is regulated at a maximum of 80mg/kg and must be declared on labels of the end product. The European Union regulates the maximum amount of canthaxanthin in fish feed at 25mg/kg. Canada regulates it in fish feed at 30mg/kg.

[Lori Anne]

Canthaxanthin is also used topically as a sunless tanning spray. 

The Effects on human pigmentation are as follows:

When ingested for the purpose of simulating a tan, its deposition in the panniculus imparts a golden orange hue to the skin.[4]:860

The FDA has no "tanning pills" approved for sale in the United States. In spite of this, there are companies that continue to market such products, some of which contain canthaxanthin. The FDA considers such items "adulterated cosmetics" and as a result sent "Warning Letters" to the firms citing such products as containing "a color additive that is unsafe within the meaning of section 721(a) of the FD&C Act (FD&C Act, sec. 601(e))."[5]

According to the FDA:

        Tanning pills have been associated with health problems, including an eye disorder called canthaxanthin retinopathy, which is the formation of yellow deposits on the eye's retina. Canthaxanthin has also been reported to cause liver injury and a severe itching condition called urticaria, according to the AAD.[6]

[Lori Anne]

While carotenoids,  in  naturally occurring form is quite safe and beneficial, canthaxanthin synthetic pigment manufactured by Hoffman-La Roche, may not be safe for consumption.  Some scientists worry that adding it to animal feeds can be harmful. IN the farmed fishing industry, fish farmers can choose just what shade of peach their fish will display from the pharmaceutical company’s trademarked SalmoFan, a color swatch similar to those you’d find in a paint store.

 Studies are still ongoing as Canthaxanthin is a relatively new feed additive, but some known side effects have been recorded.

The European Commission Scientific Committee on Animal Nutrition (SCAN) issued a warning several years ago about the pigment and urged the industry to find an alternative. In 2002, SCAN reviewed the maximum levels of canthaxanthin in fish feeds and determined that the allowable level of 80 milligrams of canthaxanthin per kilogram in feed was too high, and that consumers who ate large amounts of salmon were likely to exceed the Acceptable Daily Intake of 0.03 milligrams per kilogram human body weight. In 1997, the EU’s Scientific Committee on Food recognized a link between canthaxanthin intake and retinal problems, so in April 2002, SCAN suggested lowering the level of canthaxanthin to 25 milligrams per kilogram in feed for salmonids (baby salmon). To date, no government has banned canthaxanthin from animal feed.

Canthaxanthin was linked to retinal damage in people when taken as a sunless tanning pill, leading the British to ban its use as a tanning agent. (In the U.S., it’s still available.) Consumed In high amounts, canthaxanthin can produce an accumulation of pigments in the retina of the eye and adversely affect sight.

Interactions between canthaxanthin and lipid membranes - possible mechanisms of canthaxanthin toxicity.

Canthaxanthin may have some undesirable effects on human health, mainly caused by the formation of crystals in the macula lutea membranes of the retina. This condition is called canthaxanthin retinopathy. It has been shown that this type of dysfunction of the eye is strongly connected with damage to the blood vessels around the place of crystal deposition. The interactions of canthaxanthin with the lipid membranes and the aggregation of this pigment may be the factors enhancing canthaxanthin toxicity towards the macula vascular system. Studies indicate a very strong effect of canthaxanthin on the physical properties of lipid membranes, which may explain its toxic action, which leads to the further development of canthaxanthin retinopathy.




In feeds for laying hens canthaxanthin can be added at up to 8mg per kilogram (mg/kg) of feed. For other poultry the maximum level is 25 mg/kg – the same maximum level applies for feed for farmed salmon and trout.   At present there is no requirement to label canthaxanthin in food derived from animals that had this substance included in the diet. 


While Canthaxanthin occurs in nature, for example in aquatic crustacea such as shrimps, much of the material used by the feed industry is made synthetically.  Following initial concerns about the safety of canthaxanthin organizations have set maximum limits for the use of it in poultry and shrimp feed. 

More info can be found at World Poultry Volume 19 number 3.