Studies show that the plant pigment astaxanthin could have great antioxidant potential. The responsible food authorities have not yet approved any official health claims, but there is great interest in the carotenoid among nutrition experts and consumers. The blood-red substance is obtained from algae, for example, which sometimes turn the sea blood-red. We will give you an overview of the extraction and significance of this exciting secondary plant substance.

Astaxanthin is obtained from algae.

Astaxanthin provides the red meat of salmon

Astaxanthin is a pigment from the class of carotenoids and, due to the oxygen group it contains, belongs to the subclass of xanthophylls. Well-known representatives of this class - and also structurally related - are provitamin A, lutein and zeaxanthin . The red-violet astaxanthin is produced by some plants and yeasts, but above all by green algae. Small crustaceans that feed on these algae acquire a reddish colour as a result. Salmon, lobsters and even flamingos also owe their colour to green algae, following the food chain. The blood rain algae (Haematococcus pluvialis) has a particularly high astaxanthin content. This increases even further when the algae goes into a dormant state due to a lack of food or strong sunlight and forms a blood-red capsule. Since astaxanthin absorbs short-wave light due to its chemical structure - and therefore appears reddish - it simultaneously protects the algae from the high-energy, harmful part of sunlight. It also binds important nutrients. When the algae develop in large numbers, entire bodies of water can be colored spectacularly red. The algae owes its name to this phenomenon: blood rain. The blood rain algae is the most important natural source for the extraction of astaxanthin. We also use this natural raw material for our products.

What is the chemical structure of astaxanthin?

Chemically speaking, astaxanthin is a carbon chain with a ring structure at each end, a so-called cyclohexenone ring. The entire molecule consists of 40 carbon atoms, 52 hydrogen atoms and four oxygen atoms (C ₄₀ H ₅₂ O ₄ ). Astaxanthin can exist in three so-called stereoisomers. These are structures that are identical but mirror-inverted in certain points, comparable to left and right hands. In the case of astaxanthin, this applies to the ring structures. The configuration called "3S,3'S" has, to stay with the image, two left hands, "3R,3'R" has two right hands and "meso" has one left and one right hand. This is expressed in our graphic by the dashed connection to the hydrogen atom (H) on both sides of the molecule.

Structural formula of astaxanthin.

Natural or synthetic astaxanthin – what are the differences?

There are three methods available for the extraction of astaxanthin:

• The substance can be produced synthetically using petrochemical processes, i.e. on the basis of petroleum.
• In addition, astaxanthin can be obtained from genetically modified yeast fungi.
• Finally, as already mentioned, it can be extracted directly from highly pure cultures of the blood rain algae.

Synthetic astaxanthin is approved as a feed additive and is often used in fish farming. It is not only salmon raised in aquaculture that get their red color from it. Even salmon trout, which naturally have no red flesh, are colored by the carotenoid. While wild salmon predominantly contains 3S,3'S astaxanthin, the meso configuration predominates in farmed salmon fed synthetic feed. Another argument in favor of using natural astaxanthin from microalgae is that the substance is automatically present in an esterified form. This means that the carotenoid is bound to a fatty acid . This stabilizes astaxanthin and increases bioavailability.

Current status of studies

Carotenoids are secondary plant substances. These are substances that do not participate in the plant's vital metabolic processes, but can still perform important functions. These include, for example, coloring and flavoring agents or substances that ward off pests. We consume an estimated 1.5 grams of secondary plant substances in our daily diet. Even though they are not essential nutrients, we now know that they are involved in many metabolic processes throughout the body. Some, including astaxanthin, are even able to cross the blood-brain barrier, which can be seen as an indication of their potential. In order to understand the role that secondary plant substances play in our metabolic processes, they are increasingly the subject of scientific studies. We now know that around 50 carotenoids have provitamin A activity, meaning that they can be converted into vitamin A by the body. Beta-carotene, the best-known representative of carotenoids, has the highest activity. Carotenoids are also considered to be strong antioxidants. Studies indicate that this could also be the case with astaxanthin. The anti-inflammatory properties of the plant substance have also been investigated in many studies. However, the underlying mechanisms have not yet been conclusively clarified. For this reason, according to the European Food Safety Authority (EFSA), health-related statements on astaxanthin are currently not permitted.

How can I take astaxanthin?

The best natural sources of astaxanthin are salmon and seafood, especially crabs, shrimps and lobsters. All animals should be wild caught, as aquaculture animals are usually only fed synthetic astaxanthin. In addition, all reddish vegetables, such as peppers or carrots, can contain small amounts of astaxanthin. Food supplements offer the possibility of regularly consuming a consistent amount of natural astaxanthin. According to the EFSA, a maximum daily dose of 8 mg for an adult should not be exceeded.

External sources:

• Safety of astaxanthin for its use as a novel food in food supplements (EFSA)