Astaxanthin is an antioxidant compound that occurs naturally in sources like microalgae, yeast, salmon, crustaceans and basically any ocean plant or animal with a reddish color. Astaxanthin is used as a nutritional supplement and touted for its benefits in treating cardiovascular, immune, anti-inflammatory and neurodegenerative diseases. Many of these effects have been demonstrated in vitro or animals, but few have yet been studied on humans, although there’s hope astaxanthin may prove to be a potent disease fighter.
Antihypertensive and Neuroprotective Effects
A study published in 2005 in the "Biological & Pharmaceutical Bulletin" fed astaxanthin for 14 days to hypertensive rats and over a period of five weeks to ischemic, or stroke-prone, rats. The hypertensive rats had a significant reduction in blood pressure, while the stroke-prone rats showed a marked neuroprotective effect that delayed incidence of stroke, as well as exhibited an improved learning ability in a water maze test.
In 2006, Hokkaido University's Department of Ophthalmology and Visual Sciences investigated the effects of astaxanthin on uveitis, an inflammation of the vascular middle layer of the eye containing the iris. The astaxanthin reduced ocular inflammation in the eyes by down-regulating proinflammatory factors.
In various studies, astaxanthin has been shown to have greater antioxidant properties than other carotenoids, a class of yellow to red pigments found in plants, algae and photosynthetic bacteria. One particular project, at Finland’s University of Kuopio, investigated the effect of astaxanthin supplementation in healthy non-smoking men on lipid peroxidation, the process where free radicals steal electrons from cell membranes and cause cell damage. The astaxanthin group had a significant drop in the levels of hydroxy fatty acids that encourage inflammation as compared to the placebo group.
A study in the February 2004 issue of "Journal of Pharmacological Sciences" reported on the effects of using astaxanthin combined with ginkgo biloba to treat asthma, which showed that the combination therapy suppressed T-cell activation to a degree comparable to two commonly used antihistamines, Zyrtec and Astalin.
Results from a study published in 2004 in "BioFactors" showed a lower level of blood glucose in diabetic mice treated with astaxanthin than in a non-treated group, and that the antioxidative activity of astaxanthin reduced stress on the kidneys and prevented renal cell damage. The researchers concluded that astaxanthin may be useful in preventing diabetic nephropathy.
The Kaunas University of Medicine in Lithuania found that higher doses of astaxanthin, at 40 milligrams, didn’t cure the symptoms of patients with dyspepsia but did provide a significant reduction of reflux in patients who were infected with H. pylori, the bacteria that can lead to ulcers.
Results from a study by scientists in Rome, Italy, compared several carotenoids to see how they protected skin against the damaging effects of UVA rays from the sun. According to the study, published in 2009 in "Experimental Dermatology," fibroblasts from skin were treated with the carotenoids before being exposed to UVA, with only astaxanthin showing a significant photoprotective effect, modulating most of the UVA-induced injuries.