Health Benefits Of The Carotenoid Antioxidant Astaxanthin
Astaxanthin is an antioxidant compound that occurs naturally in sources like microalgae. Astaxanthin is used as a nutritional supplement and touted for its benefits in treating cardiovascular, immune, anti-inflammatory and neurodegenerative diseases
Microalgae may be - gram-for-gram - the most nutrient dense food on Earth. Microalgae use light to make energy more efficiently than higher plants. Health experts have long been impressed by the nutritional properties of marine microalgae such as spirulina and chlorella, both now known superfoods.
Now, yet another microalga is now in the spotlight - one that contains a dark red lipid-soluble pigment, the richest known source of the carotenoid astaxanthin.
Only plankton, algae, certain bacteria and fungi are able to make astaxanthin on their own. All animals, including us humans, must consume carotenoids in our diet. Astaxanthin is what gives the reddish-orange color to salmon, shrimp, red fish, and lobster and feathers of birds such as flamingoes and quail. Both its bright color and powerful antioxidant function are a direct result of its chemical structure.
The main natural source of astaxanthin is the microalga H. pluvialis. This alga accumulates the highest levels of astaxanthin in nature - more than 40 g can be obtained from just one kg. Not only that, its population doubles every week, which means scaling up is not a problem. However, expertise is needed to harvest this alga with high astaxanthin content.
It is grown in two phases. In the first, green phase, the alga is given plenty of nutrients to promote growth. In the second red phase, it is deprived of nutrients and subjected to intense sunlight - which is when it starts to make a lot of astaxanthin to protect itself against environmental stress and is harvested.
The yeast X. dendrorhous is also an excellent source of astaxanthin, which is more easily absorbed by our body relative to synthetic and bacterial sources. Krill is also an astaxanthin source, but krill fishing is typically done in Antarctic waters under extreme weather conditions, far away from modern facilities - which drive up production costs. Finally, astaxanthin is also commercially collected from shrimp processing waste.
Astaxanthin is both a nutritional compound and a food supplement. It is also approved for use as a food coloring (or color additive) for specific uses in animal and fish foods by the U.S. FDA.
Carotenoid antioxidants are known for their ability to neutralize damage-causing free radicals. Each carotenoid’s ability to neutralize free radicals is heavily modified by its water and fat solubility and therefore varies with the type of system being protected.
When researchers determined the free radical-fighting capacity of various carotenoids, they found that vitamin E was the most effective in terms of its electron donor capacity, whereas astaxanthin was the most effective in terms of its electron acceptor capacity.
Astaxanthin is not converted to vitamin A in the human body. Like other carotenoids, astaxanthin has very low toxicity when taken by mouth.
Protecting mitochondria against oxidative stress
Mitochondria are cellular furnaces in which ATP is generated for the cell’s energy needs. During this process, oxygen-derived free radicals are also that damage mitochondria via oxidative stress - a critical factor in many diseases such as cancer, brain disorders and lifestyle-related diseases.
Scientists in Japan have found that astaxanthin lowers oxidative stress and protects cultured cells from free radicals. Not only that, it boosts mitochondrial respiration, increasing levels of cellular energy. Finally, astaxanthin improves mitochondria’s ability to maintain its functional integrity when attacked by oxygen-derived free radicals.
Protecting the brain against free radicals
Uniquely, astaxanthin has been found to be capable of crossing the blood-brain barrier in mammals, including humans. This allows astaxanthin to protect the brain, which is highly susceptible to damage by free radicals.
When scientists in Japan treated cultured brain cells with various neurotoxins, many of them died - unless they were pretreated with astaxanthin, which protected them by blocking free radical generation. These results suggest that astaxanthin may effectively prevent oxidative stress-associated damage to the brain.
Protection against many types of cancer
In a study from the Catholic University School of Medicine in Rome, Italy, treatment with astaxanthin was seen to slow down cell growth and even cause death in different types of cancerous cells, especially colon cancer.
Several studies have shown that astaxanthin is also highly effective against other forms of cancer, including urinary bladder cancer in mice and oral and colon cancer in rats. Researchers in China found that the carotenoids beta-carotene, lycopene, zeaxanthin, and astaxanthin all prevented cell growth in cultured breast cancer cells.
Health experts are very excited about the possible role of astaxanthin as an anti-cancer medication and research into this area is continuing.
Not only that, astaxanthin has also been shown to:
- Protect against induced cataracts
- Protects against gastric mucosal injury and the secretion of acid by gastric cells during ulcer disease
- Effectively prevent progression of diabetic complications in combination with Flavangenol, an extract from French maritime pine bark
- Block inflammation, making it a suitable candidate for therapy against cardiovascular oxidative stress and inflammation
- Significantly influence immune function