What is astaxanthin?
Astaxanthin is a member of the carotenoid family and a close relative of the more familiar beta-carotene and lutein. The most abundant natural source of asta-xanthin is the marine microalgae Haematococcus pluvialis, but it's also found in a variety of seafood, including salmon, shrimp, lobster and crab-where it's responsible for their distinctive pink hue.
Being a carotenoid, astaxanthin is a powerful antioxidant-a molecule that can protect cells against damage caused by unstable molecules known as 'free radicals'. However, unlike other carotenoids, which can show potentially damaging pro-oxidative properties under certain conditions (for example, if other antioxidants are lacking), astaxanthin is a 'pure antioxidant' (Biosci Biotechnol Biochem, 2009; 73: 1928-32).
Studies demonstrate that astaxanthin's antioxidant ability surpasses that of other carotenoids such as beta-catotene, lycopene and lutein, as well as vitamin E (J Agric Food Chem, 2000, 48: 1150-4). By neutralizing singlet oxygen, a highly reactive oxygen compound, astaxanthin has a potency more than 100-fold higher than that of vitamin E (Pure Appl Chem, 1991; 63: 141-6).
These antioxidant capabilities, coupled with its ability to cross the blood-brain barrier (Pharmacol Biochem Behav, 2011 May 17; Epub ahead of print), make astaxanthin an ideal candidate for the prevention and treatment of a range of diseases and conditions. In particular, as free-radical formation and oxidative stress are thought to play key roles in ageing (Mech Ageing Dev, 2004; 125: 811-26), a growing number of supplement suppliers and manufacturers are promoting astaxanthin as an anti-ageing 'super nutrient'.
The scientific evidence
Numerous studies, including several clinical trials, show that the nutrient may be beneficial for a variety of conditions associated with ageing.
- Dementia. A Japanese study found that astaxan-thin can reduce the buildup of compounds called 'phospholipid hydroperoxides' (PLOOH), which are known to accumulate abnormally in the red blood cells (erythrocytes) of people with dementia. In this randomized double-blind trial, 30 healthy volun-teers aged 50-69 years were given an astaxanthin supplement (6 or 12 mg) or a placebo pill every day for 12 weeks. The results showed that PLOOH levels in erythrocytes declined by 40 and 50 per cent with 6 and 12 mg of astaxanthin, respectively, whereas there was no change with the placebo. The researchers concluded that astaxanthin "may contribute to the prevention of dementia" (Br J Nutr, 2011; Jan 31: 1-9; Epub ahead of print). Another study-albeit a preliminary investiga-tion-found that astaxanthin supplements may be useful for age-related forgetfulness and cognitive decline (J Clin Biochem Nutr, 2009; 44: 280-4).
- Poor eyesight. In a trial published in the Japanese journal Medical Consultation & New Remedies, astaxanthin (6 mg/day) was given to 22 middle-aged and older people with signs of presbyopia-where the lens of the eye loses its ability to focus (known as 'accommodation'), making it difficult to see objects up close. The researchers found a significant improvement in eye accommodation ability after astaxanthin supplementation for four weeks (Med Consult N Rem, 2009; 46: 89-93). However, it should be borne in mind that the study was sponsored by Fuji Chemical Industry (FCI), the company that manufactures the astaxanthin supplement AstaReal. Another trial-a year-long Italian study-reported that taking 4 mg of astaxanthin daily in combination with other carotenoids and antioxidants (180 mg of vitamin C, 30 mg of vitamin E, 22.5 mg of zinc, 1 mg of copper, 10 mg of lutein and 1 mg of zeaxanthin) improved visual function in patients with age-related macular degeneration (Ophthalmology, 2008; 115: 324-33.e2).
- Skin ageing. Several studies show that astaxanthin offers natural protection against the sun's harmful ultraviolet (UV) rays, which are the number-one cause of premature skin ageing. A recent test-tube study reported that astaxanthin displayed superior protective effects against UVA-induced oxidative damage in human skin cells compared with the carotenoids canthaxanthin and beta-carotene (Exp Dermatol, 2009; 18: 222-31). Another laboratory study revealed that astaxanthin slows the increased production of the collagen enzyme matrix-metalloproteinase-1 (MMP-1) and skin fibroblast elastase (SFE) enzyme trigged by UVA exposure. As these enzymes break down skin collagen, elastin fibres and connective tissue, the researchers hypothesized that astaxanthin might offer significant protection against skin sagging and wrinkling (J Dermatol Sci, 2010; 58: 136-42). Even more exciting, clinical trials suggest that taking astaxanthin may actually improve the condition of the skin. In a double-blind study funded by FCI, 16 women with dry skin, aged around 40 years, were split into two groups. One received a daily supplement containing 2 mg of astaxanthin and 40 mg of tocotrienol (vitamin E), while the other received a placebo capsule containing canola oil. After just two weeks, the women in the test group saw numerous improvements in their skin's condition, including fewer wrinkles, better moisture and elasticity, a smoother surface, and less under-eye darkness and flabbiness. The results were even better after four weeks, with various skin measurements showing a statistically significant change compared with the control group (Food Style 21, 2002; 6: 112-7). A more recent study by FCI using a larger sample size (49 American women) investigated the effects of astaxanthin alone (4 mg daily) on skin condition. After six weeks, marked improve-ments were again noted in the astaxanthin group compared with the placebo group, including a significant improvement in elasticity and fine lines/wrinkles, as assessed by a dermatologist (Carotenoid Sci, 2006; 10: 91-5).
Small dose, big benefits
Besides these promising anti-ageing benefits, astaxanthin may also be able to prevent cancer, boost fertility and improve heart health (see box above). However, much larger clinical trials are needed, particularly ones that examine the long-term safety of consuming astaxanthin on a daily basis. Nevertheless, so far there have been no reports of adverse effects, and studies have used oral astaxanthin at dosages ranging from 1.8 mg to 100 mg per day, administered from a single dose up to daily dosing for a year (Mar Drugs, 2011; 9: 447-65). What's more, a human safety study concluded that 6 mg/day of astaxanthin-extracted from H. pluvialis-is safe for healthy adults (J Med Food, 2003; 6: 51-6).
If you do wish to try it, make sure you choose a natural astaxanthin supplement from an unpolluted source of the microalgae, such as Higher Nature's AstaPure Timeless Beauty (lb15.95 for 30 4-mg gel capsules; www.highernature. co.uk).
The usual dose of astaxanthin is 2-4 mg/day and, as it's fat-soluble, it appears to be absorbed best when taken after a fat-containing meal (Biosci Biotechnol Biochem, 2009; 73: 1928-32). In general, it's recommended to take it with a dietary source of healthy fats, such as olive or flaxseed oil.
When combined with a healthy diet and lifestyle, astaxanthin may well be one of the best supplements around to help delay those dreaded signs of ageing.
WDDTY VOL 22 NO 4