Astaxanthin as a dietary supplement
Astaxanthin is a natural carotenoid pigment that gives salmon and various sea creatures their distinctive pink color. As a dietary supplement, it is promoted for its antioxidant properties and potential health benefits, although scientific support for many of these claims is limited. Proposed uses include prevention of cataracts, support for heart health, assistance with high cholesterol and blood pressure, and even enhancements in male fertility and athletic performance. Dietary sources of astaxanthin include salmon and krill oil, with doses in studies typically ranging from 4 to 16 mg daily.
While some research suggests astaxanthin may help combat oxidative stress and improve brain function in older adults, results are mixed, and many findings are based on small studies or used in combination with other supplements. Although generally recognized as safe and well-tolerated, high doses may lead to mild side effects, such as digestive issues or changes in stool color. It's important to approach astaxanthin with caution, as its effectiveness for various health claims remains unproven and further research is needed to establish its true benefits.
Astaxanthin as a dietary supplement
DEFINITION: Natural substance used as a dietary supplement for specific health benefits.
PRINCIPAL PROPOSED USES: None
OTHER PROPOSED USES: Cataracts prevention, dyspepsia, heart disease prevention, high blood pressure, high cholesterol, macular degeneration prevention, male infertility, sports and fitness support, promote brain health, boost immunity, aid skin health
Overview
Astaxanthin, a substance in the carotenoid family, gives salmon and many other sea creatures their pink color. Like other carotenoids, astaxanthin is a strong antioxidant. It has been advocated for treating or preventing several health conditions, but few of these proposed uses are supported by meaningful scientific evidence.
Requirements and Sources
Astaxanthin is not an essential nutrient. However, an 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 a 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 a 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.
Further astaxanthin studies showed the potential for providing short- and long-term benefits for cancer survivors. In a study of breast cancer survivors, astaxanthin appeared to slow the growth of returning cancer cells. Human studies have also produced favorable results in looking at astaxanthin’s utility in anti-aging products. Studies have produced conflicting results on whether astaxanthin benefits exercise endurance and heart health.
Weak evidence also 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 a placebo for treating stomach irritation in people with dyspepsia (nonspecific stomach pain).
An area that has gained support through scientific study is the use of astaxanthin to combat the effects of oxidative stress on the body, which can lead to degenerative conditions in the brain and eyes. In clinical studies where participants were given astaxanthin, older adults appeared to improve their brain function compared to patients in the placebo group, suggesting astaxanthin may help with neurodegenerative conditions, such as dementia. Similarly, participants in another study who were given astaxanthin appeared to increase blood flow to their eyes, combatting many eye conditions astaxanthin was theorized to help. However, it is essential to note that these small studies sometimes produced conflicting results, and astaxanthin was combined with other supplements.
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. Consuming astaxanthin at very high doses may cause frequent bowel movements or red stools.
Bibliography
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Wu, T. H., et al. "Astaxanthin Protects Against Oxidative Stress and Calcium-Induced Porcine Lens Protein Degradation." Journal of Agricultural and Food Chemistry, vol. 54, 2006, pp. 2418-2423.