Astaxanthin (3,3′-dihydroxy-ß,ß'-carotene-4,4′-dione) is an antioxidant in the Carotenoid family belonging to a sub-group called keto-carotenoids. Beta-carotenoids commonly found in carrots, tomatoes and pumpkins are another sub-category of carotenoids that most people would have heard about. Biological astaxanthin was first discovered in the body of lobsters and salmons. It can also be found in krill, shrimp, microalgae and yeast.
Astaxanthin can dock into the cellular membrane (the outer layer of every cell), same as vitamin E. It can cross the blood-brain barrier, which is one of the reasons why it is so interesting for research due to its potential neuroprotective effects on the brain.
The problem with obtaining astaxanthin in a therapeutic dose is that we would have to consume a huge amount of seafood. According to one study, "if people take 4 mg astaxanthin in daily consumption, they need to eat about 600 to 2000 g salmon or seafood every day" This could be expensive and potentially even toxic due to frequent contamination of seafood with heavy metals and persistent organic pollutants. And so the alternative way is to take it in a supplemental form.
Astaxanthin, Oxidative Stress & Cancer
Note to reader: This chapter is a bit technical & geeky. In case you are not interested in some of those technical details, please skip to "Astaxanthin & Sports Performance"
Oxidative stress is one of the main contributors to the development of chronic disease. It is gradual, cumulative damage to tissues, cells and cellular DNA by molecules called the free radicals. Free radicals are a side product of normal metabolism and any basic body function, such as energy production. However, they are also a side product of chronic inflammation which is in the middle of every single systemic disease. When the amount of oxidative stress (or chronic inflammation) overwhelms the body's antioxidant defences, the disease develops and may potentially grow into something like cancer.
A large study (Faraone et al. 2020) has collected all available smaller studies on the effects of astaxanthin in-vitro and in-vivo on cancer tissue. Here are some of the incredible findings they found. (Remember these were not human studies)
Astaxanthin reduces the production of pro-inflammatory molecules called interleukins and eicosanoids. These may trigger systemic & persistent inflammation in the body.
Astaxanthin helps protect mitochondria (the main engine of the cell) from oxidative damage, potentially preventing mitochondrial dysfunction, which is often present in diseases such as fibromyalgia and chronic fatigue syndrome
In-vitro, astaxanthin supports activation of a family of molecules called PPARs (Paroxisome Proliferator Activated Receptors) – what these do is improve metabolic efficiency by improving insulin sensitivity, improving glucose uptake from cells and reducing fatty acid storage. PPAR activation is a target of many drugs used to treat diabetes. PPARs also activate adiponectin, an essential hormone that also improves metabolic efficiency.
In-vitro, astaxanthin also activates an intracellular (inside the cell) pathway called NRF2 (Nuclear factor erythroid 2-related factor 2). This pathway increases the production of a variety of protective antioxidants in the body. NRF2 activation also improves detoxification of drugs, toxins and pesticides in the liver through a variety of different pathways, one of which is the production of glutathione, the master antioxidant.
Astaxanthin & Sports Performance
A unique study (Earnest, 2011) that was done on semi-professional cyclists measured their performance on a 20km bicycle before a 28-day supplementation of astaxanthin (or placebo) and after. This study was, unfortunately, really small, and only 14 people completed it. What they found was that the astaxanthin has significantly improved their time on a 20-minute bike track. What was even more interesting was that they had no idea how that happened. While they also measured for markers such as lactate, maximum oxygen update (VO2 max), carbohydrate oxidation and others, they saw no difference in any of those markers.
Researchers came with a theory based on some previous mice studies that showed that astaxanthin in mice improves the utilisation of fats for energy by improving the rate at which they are transported to mitochondria (the engine of the cell). Personally, I'm inclined to be in favour of this theory. It makes a lot of sense, especially when you look at the picture below that shows that there was a clear improvement of fatty acid oxidation (means ↑ burning of fat for energy) in the cyclists using astaxanthin. But I guess we need more studies of this kind to be able to tell for sure.
Astaxanthin & Skin Health
In a small Japanese study (Ito & Ueda, 2018) volunteers supplemented on astaxanthin for 8 weeks had better resistance to UV-induced skin damage (in lab) and better skin recovery from this damage. It took a longer time to induce the same amount of skin damage as in the non-astaxanthin group.
The chart below shows reduced skin damage from same amount of UV-light exposure in the astaxanthin group. On the right side, the charts shows increased MED (minimal erythema dose) which means that in the astaxanthin dose it took more UV exposure to induce the same time of damage than in placebo. In other worse, the skin obtain better ability to defend itself from UV radiation.
In another study (Tominaga et al. 2011) 8-week supplementation with astaxanthin has resulted in improvement of skin elasticity, mild wrinkle reduction and also mild skin spot reduction. Astaxanthin strengthens the collagen fibrous tissue and appears to protect it from oxidative damage induced by UV-rays of the sun.
These two studies shows promising effects of astaxanthin's oxidative protection for people who get a lot of skin damage from the sun or people who are trying to repair a damage that has been caused by sun in the past. It would still be preferable to seek out a sun shelter rather than to overexpose oneself to the sun relying on supplemental antioxidants.
A study on obese people (Choi et al. 2011) found that those taking astaxanthin for up to 3 weeks had dramatically reduced markers of oxidative stress. What does this mean? Oxidative stress is one of THE MOST significant contributors to chronic diseases, including cancer and heart disease. It is common for obese people to have high levels of oxidative stress, and this is probably the main reason why obese people are at dramatically increased risk of cancer, heart disease and diabetes - the three leading killers of men and women in the world.
In a small study (Mashadi et al. 2018) 44 participants with a medically diagnosed type 2 diabetes were randomly divided into astaxanthin and placebo groups. After 8 weeks, the placebo group had no improvement. The astaxanthin group had some pretty significant results:
improvement of the "good" HDL cholesterol
reduction of the "bad" LDL cholesterol
improvement of the triglyceride levels (means body has become more efficient utilising fats for energy)
And finally, a hormone called adiponectin has also increased in the astaxanthin group. Adiponectin improves metabolic efficiency, insulin sensitivity and fatty acid utilisation for energy. This is a good sign. Despite the small size of this study, this was a profound finding. Something like this we would expect with metformin, the standard type 2 diabetes medication. In fact, it is adiponectin that is predominantly targeted by many of these medication and seeing that a natural supplement managed to produce this result begs for more research to see if astaxanthin could have a potential use in diabetology and cardiology. Personally, I am really excited by this finding and hope to see more and larger trials on astaxanthin in the future.
Cognitive Function & Neuroprotection
The human brain is probably the most fragile organ when it comes to vulnerability to oxidative stress. This is because it is extremely rich in fats, especially polyunsaturated fatty acids, which are easily oxidised. It also does not have a significant proportion of antioxidants compared to other tissues such as the liver or the lungs. The main way the brain has always been protected was the blood-brain barrier, a mechanical barrier that prevents entry of toxins and free radicals, however in the modern world where we become exposed to more and more toxins, stress and inflammation from diet and environment, this barrier is no longer 100% effective, and brain can often get damaged by chronic inflammation or heavy metals. We see results of this in samples taken from people with progressed Alzheimer's, Parkinson's or other neurodegenerative conditions where over decades of oxidative damage, structural changes, scar tissue and necrosis has developed.
For this reason, much research has been focusing on increasing antioxidant defences for the brain. Astaxanthin may have a potential use here. It has been found that astaxanthin derived from fish or algae has an ability to cross the blood-brain barrier, although it is not yet know how it is distributed and what happens once it crosses the BBB. At least not in humans.
We also have some lab studies in rats to show that astaxanthin supplementation increases levels of BDNF (the key driver of brain neuroplasticity, see previous blog articles on BDNF). Unfortunately, in the only human study that ever looked at BDNF after astaxanthin (Ito et al. 2018). supplementation in the elderly, BDNF remained unchanged. The study population on astaxanthin had some mild improvement on psychomotor tests thou.
In a small size Italian study (Crosta et al 2020) 80 elderly subjects were recruited and divided randomly into active and placebo groups. The active group received a supplement product made of bacopa monnieri (popular nootropic), lycopene (a carotenoid found in tomatoes and watermelon), astaxanthin and vitamin B12. After 8 weeks, the active group had a very decent improvement in their cognitive performance, verbal fluency, verbal learning and overall executive performance compared to placebo, where no such results were seen. In this study, it was possible that the effects could have been due to bacopa, lycopene or B12 or a combination of all rather than astaxanthin single-handedly.
And so, based on the research so far, astaxanthin only has theoretical benefits for cognitive health, possibly more for the elderly than for young people. Compared to some of the other natural products such as L-Theanine, Ginkgo or Green tea, astaxanthin definitely wouldn't be my go-to if brain performance optimisation was the goal of the client.
SUMMARY & KEY POINTS
Astaxanthin is a natural antioxidant from the carotenoid family first discovered in the body of lobsters and salmon. It is responsible for its vivid red/orange colouring
Astaxanthin has shown some incredible anti-cancer and anti-inflammatory benefits in-vitro (in a petri dish) and in-vivo (small lab animals)
In a study on amateur cyclists, 28-day supplementation of astaxanthin resulted in significant improvement of the time it took to cross 20km distance compared to the placebo group where no such improvement was seen. It appears astaxanthin may improve utilising of stored fats (fatty acids) for energy. The study also found that those in the astaxanthin group were able to pedal with greater energy output.
Astaxanthin may be able to reduce markers of oxidative stress in obese people and improve cholesterol levels and overall metabolic efficiency in diabetics. These profound findings beg for more studies and the potential use of astaxanthin alongside diabetic treatment in the future.
In terms of cognitive performance, astaxanthin still has questionable efficacy. There are only very few studies available and those show unclear effects. While astaxanthin has the ability to cross the blood-brain barrier and (theoretically) have potent antioxidant effects in the brain, so far, we lack proper evidence in humans and the few trials we have are not convincing enough.
SAFETY, DOSAGE & TOLERABILITY
Astaxanthin is usually well-tolerated and safe to take. In a few studies, some minor reports of digestive discomfort have been noted. A daily intake between 16-40mg has been deemed safe and well-tolerated.
Because we do not have studies of its long-term effects, I would not suggest using it indefinitely as a matter of long-term prevention. It may be of use to diabetic patients (after a consultation with their doctor) as well as long-distance endurance athletes and people looking to repair a past skin damage from the sun overexposure.
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Choi, H.D. et al. (2011). ‘Effects of astaxanthin on oxidative stress in overweight and obese adults’, Phytotherapy research: PTR, [abstract] 25 (12), pp.1313-1318.
Crosta, F. et al. (2020). ‘Improvement of Executive Function after Short-Term Administration of an Antioxidants Mix Containing Bacopa,Lycopene, Astaxanthin and Vitamin B12: The BLAtwelve Study’, Nutrients, 13 (1), pp.56
Earnest, C. P. et al. (2011) ‘Effect of astaxanthin on cycling time trial performance’, International Journal of Sports Medicine, 32(11), pp. 882–888.
Faraone, I. et al. (2020) ‘Astaxanthin anticancer effects are mediated through multiple molecular mechanisms: A systematic review’, Pharmacological Research, 155