What is astaxanthin as a dietary supplement?

Overview

Astaxanthin, a substance in the carotenoid family, provides the pink color of
salmon and many other sea creatures. Like other carotenoids, astaxanthin is a
strong antioxidant. It has been advocated for treating or
preventing a number of health conditions, but none of these proposed uses is
supported by meaningful scientific evidence.

Requirements and Sources

Astaxanthin is not an essential nutrient. However, it is possible that increased intake of astaxanthin could provide health benefits.

Salmon is an excellent source of astaxanthin. A typical serving of Atlantic salmon provides approximately 1 milligram (mg) of astaxanthin, while a similar serving of Pacific salmon might provide 4 to 5 mg. Krill oil is another good food source of astaxanthin.

When consistently exposed to high levels of ultraviolet light, the alga Haematococcus pluvialis produces very large quantities of astaxanthin, presumably to protect itself from injury. Haematococcus raised in this way is used as a commercial source of astaxanthin.

Therapeutic Dosages

In studies, astaxanthin has been given in doses ranging from 4 to 16 mg daily. Some evidence suggests that astaxanthin is better absorbed when consumed in an oily base.

Therapeutic Uses

Many health claims for astaxanthin are based on its strength as an antioxidant.
However, scientific confidence in the medical benefits of antioxidants has waned;
study after study of antioxidants such as vitamin E and
beta-carotene have failed to find the hoped-for benefits.

Other proposed uses of astaxanthin have some marginal supporting evidence from double-blind studies. In one such study, thirty men with infertility were given either placebo or 16 mg of astaxanthin daily for three months. The results showed possible small benefits on laboratory measures of fertility.

Another study tested astaxanthin combined with the carotenoid lutein as a possible supplement for enhancing recovery from exercise. In this small trial, twenty bodybuilders were given either placebo or the carotenoid combination for three weeks. Participants then engaged in intense exercise. The results failed to show that the use of the astaxanthin and lutein combination reduced muscle soreness or signs of muscle injury.

Weak evidence additionally hints that astaxanthin might reduce blood pressure,
help prevent heart disease, lower cholesterol, protect the lens of the
eye against cataracts, protect the stomach against ulcers, and reduce
the risk of macular degeneration. However, for none of these uses (or
any other) can astaxanthin be remotely called a proven treatment. Also, two
studies failed to find astaxanthin significantly more effective than placebo for
treating stomach irritation in people with dyspepsia (nonspecific stomach
pain).

Safety Issues

As a widely consumed nutritional substance, astaxanthin is expected to have a low order of toxicity. In human studies, no serious adverse effects have been seen. Maximum safe doses in pregnant or nursing women, young children, or persons with severe liver or kidney disease have not been determined.

Bibliography

Bloomer, R. J., et al. “Astaxanthin Supplementation Does Not Attenuate Muscle Injury Following Eccentric Exercise in Resistance-Trained Men.” International Journal of Sport Nutrition and Exercise Metabolism 15 (2005): 401-412.

Comhaire, F. H., et al. “Combined Conventional/Antioxidant ‘Astaxanthin’ Treatment for Male Infertility.” Asian Journal of Andrology 7 (2005): 257-262.

Higuera-Ciapara, I., L. Felix-Valenzuela, and F. M. Goycoolea. “Astaxanthin: A Review of Its Chemistry and Applications.” Critical Reviews in Food Science and Nutrition 46 (2006): 185-196.

Kupcinskas, L., et al. “Efficacy of the Natural Antioxidant Astaxanthin in the Treatment of Functional Dyspepsia in Patients with or Without Helicobacter pylori Infection.” Phytomedicine 15 (2008): 391-399.

Spiller, G. A., and A. Dewell. “Safety of an Astaxanthin-Rich Haematococcus pluvialis Algal Extract.” Journal of Medicinal Food 6 (2003): 51-56.

Wu, T. H., et al. “Astaxanthin Protects Against Oxidative Stress and Calcium-Induced Porcine Lens Protein Degradation.” Journal of Agricultural and Food Chemistry 54 (2006): 2418-2423.