Many of the pigments in colorful plant foods possess antioxidant/anti-inflammatory powers.
These include polyphenols — found in berries, tea, coffee, and cocoa — and carotenoids, which include the carotenes and xanthophylls found in orange, yellow, and green produce.
But a highly healthful, unusually promising member of the xanthophyll (zan-tho-fill) family is often overlooked.
We're talking about astaxanthin (ass-tuh-zan-thin) — the orange-red antioxidant pigment produced by marine algae, in part to protect their DNA from sunlight-induced damage.
Astaxanthin gets passed up the ocean food chain, first to algae-eating crustaceans such as shrimp and krill, and then to wild Pacific salmon, whose diets feature those tiny creatures.
A salmon’s flesh is white at birth, but gradually turns orange-red as the fish continuously consumes astaxanthin-rich crustaceans.
Wild Pacific salmon — sockeye, king, silver, keta, and pink salmon — are the richest food sources of astaxanthin by far.
Because sockeye salmon feed mostly on crustaceans, these particular fish — aptly nicknamed “red” salmon — provide the most astaxanthin per pound.
Astaxanthin appears to enhance the endurance salmon need to swim upstream and spawn just before they die.
Absent astaxanthin, salmon would suffer debilitating oxidation in their cells, lose energy, and die before completing their exhausting marathon.
Astanxthin: A brief overview
Research into the potential health benefits of astaxanthin has been growing fast.
In cell studies, it inhibits cancer growth, and in animal studies, astaxanthin reduces inflammation, heart and liver damage, cholesterol levels, and risk of stroke.
Human studies are scarcer, but suggest that astaxanthin can enhance endurance, improve skin appearance, beneficially modulate immune response, dampen inflammation, and reduce certain risk factors for cardiovascular disease.
Astaxanthin may also help protect the aging brain from decline. As researchers from the University of South Florida wrote earlier this year, “Results from [the available research] … implicate astaxanthin as a promising therapeutic agent for neurodegenerative disease.” (Grimmig B et al. 2017)
Although the astaxanthin in wild salmon, salmon oil, and krill oil is certainly beneficial, these sources provide amounts too small to produce measurable health impacts.
Supplemental astaxanthin delivers far higher doses — amounts that typically produce beneficial effects in both animal and human studies.
Clinical study: Astaxanthin fights mental and physical fatigue
Fatigue ranks among the most common complaints expressed to physicians.
Earlier studies indicate that astaxanthin can enhance physical and mental endurance.
In the latest such study, Japanese researchers tested whether astaxanthin could fight mental and physical fatigue (Hongo N et al. 2016).
The study was designed to induce fatigue and stress like that encountered in daily life.
For the mental-fatigue challenge, study participants were given the Uchida-Kraepelin test: a series of timed calculations that require intense concentration.
To test the effects of astaxanthin on physical fatigue, volunteers rode a bicycle equipped with a gauge called an ergometer.
Encouragingly, supplemental astaxanthin significantly reduced the participants’ reported feelings of mental and physical fatigue, compared to the placebo.
These benefits included improvements in clarity of thinking, concentration, motivation, and mood in the astaxanthin groups, as well as reduced perceptions of irritation and body heaviness.
And, during the second half of the calculation test, the astaxanthin group committed far fewer errors than the placebo group.
Finally, levels of a proven biomarker of mental stress — salivary cortisol — were significantly reduced in the astaxanthin group.
Anti-aging effects seen in pioneering animal study
Landmark findings from Hawaii suggest that astaxanthin may slow the aging process.
The study was performed by researchers from the NIH-funded Lifespan and Healthspan Studies Center at the University of Hawaii.
Researchers at the Center tested the effects of astaxanthin on the FOXO3 gene, which occurs in all mammals — including humans — and plays proven roles in health and longevity.
This gene is called FOXO3 because it activates the FOXO3 protein, which is part of the “Forkhead box” or FOXO group of proteins.
FOXO proteins exert strong influences on cell metabolism, growth, aging, and differentiation, as well as oxidative stress and inflammation.
Certain FOXO genotypes — and/or abnormal expression of FOXO proteins — either discourage or promote metabolic disease, cancer, and reduced lifespans, in animals and humans alike.
“All of us have the FOXO3 gene, which protects against aging in humans,” said professor Bradley Willcox, the center’s director and principal investigator.
But only about one in three people carry the "G" version of the FOXO3 gene, which appears to discourage heart disease and promote longevity.
Evidence from two population studies involving 6,235 older men showed that — over a 17-year period — those who carried the FOXO3 “G” genotype were 10 percent less likely to die from any cause and 26 percent less likely to die from coronary heart disease.
As Dr. Willcox said, “By activating the FOXO3 gene common in all humans, we can make it act like the ‘longevity’ version. Through this research, we have shown that astaxanthin ‘activates’ the FOXO3 gene.”
In the study, mice were fed either normal food or food containing a low or high dose of astaxanthin.
Animals fed the higher dose of astaxanthin displayed a nearly 90 percent increase in activation of the FOXO3 gene in their heart tissues.
The researchers intend to test the effects of astaxanthin in other tissues where the FOXO3 gene is expressed, including the liver, muscle, and brain.
The Hawaiian team also plans to test the ability of astaxanthin to improve cognitive function in people who suffer from early dementia.
We'll be sure to report on the results of those studies, if and when they're performed and published.