We are discussing—some would say dissecting—the article, Astaxanthin: A Rising Star in Alzheimer’s Prevention. In my opinion, the first six paragraphs of this article were reasonably accurate, but did make some misleading implications.
The most inaccurate implication made was the notion that there is some regimen that is known to protect one against Alzheimer’s disease. There is not. Although we are aware of some factors that increase the probability of getting the disorder, avoiding those things does not guarantee protection. And although we are also aware of some behaviors that enhance brain health, practicing those behaviors does not necessarily protect against neurodegeneration.
But let’s move on. The article talks about astaxanthin, a potent natural antioxidant. Research on astaxanthin is not new—the reference cited in the article is from 2009, but there has been a large commercial market for astaxanthin for over thirty years (Ref. 1).
Astaxanthin is a carotenoid, a natural pigment in the same family as the pigments that give color to carrots and pumpkin. Carotenoids are interesting because in addition to providing attractive color to many foods, they often play essential roles in cell health. Animals cannot make carotenoids. They get these pigments from their diet.
As mentioned in the original article, astaxanthin in their diet changes flamingo feathers from grayish to pink. This is not an exciting or mysterious process. Astaxanthin is a pigment that builds up in the feathers, so it simply dyes them pink.
The rich pink color of salmon meat also comes from astaxanthin, which the fish ingest in the wild as part of their natural diet. When salmon are farmed, astaxanthin is added to their food to give the meat the color consumers expect it to have. So the commercial market for astaxanthin developed in the early 1980s, as salmon farming became more common. By 1990, Roche pharmaceutical company began large-scale production of synthetic astaxanthin (Ref. 3).
As early as 1992, astaxanthin had been recognized as a molecule capable of strongly opposing oxidation (a potent antioxidant—Ref. 2). When most people think of oxidation, they think of rust. But in a biological system, oxidation amounts to the stealing of electrons from one molecule by another molecule containing an electron-hungry atom. Oxygen is notoriously electron-hungry and is very common in biological systems, which is probably why the process got named oxidation. But there is more to the story.
You have probably heard of free radicals, and know that they are dangerous to cells. Well, a free radical is nothing more than a molecule that is a super-strong oxidizing agent. That is, it can rip electrons from other molecules with great ease. This is not a good thing.
Why not? Because having a full compliment of electrons (a full outer shell, if you remember some chemistry) stabilizes molecular structure. Just like a well-placed hit with a wrecking ball can bring a whole building down, so an interaction with a free radical can destroy a molecule.
Anti-oxidants (like astaxanthin) go one-on-one with free radicals and neutralize them. That is how they protect cells from damage.
Do cells need this protection?
Cells normally manufacture antioxidant molecules themselves. Plant cells manufacture carotenoids like astaxanthin. Animal cells make their own antioxidants, too. In a perfect world, between the antioxidants our cells produce and the antioxidants in a healthy diet, we’d have plenty of defense against free radicals. But the world isn’t perfect. There are many environmental stresses that increase the number of free radicals our bodies must contend with. The highly processed foods we eat don’t help matters any. It is not a bad idea to increase our intake of antioxidants. You probably could name a handful of foods high in antioxidants without even thinking too hard: blueberries, dark chocolate, many vegetables, green tea, and more.
But are these things a defense against Alzheimer’s?
Maybe. In many illnesses, including Alzheimer’s, free radicals tend to be increased. Maybe more of these nasty molecules are being made, or maybe the body’s own defensive antioxidant production is dropping off. Either way, adding more protective antioxidants would seem to be a good idea. But when clinical trials have been run to test this idea, the results have been mixed, largely because in any dietary study there are so many variables that are hard to control.
The idea still has merit. The National Institute on Aging is beginning a new, nationwide clinical trial, not on astaxanthin, but on resveratrol—the antioxidant in red wine and dark chocolate. Antioxidants are still an area of active research. And among antioxidants, astaxanthin does appear to have some unique characteristics. We’ll get into those next time.
In the meantime, there are many good sources of antioxidants. I include a wide variety of them in my diet because they are delicious and good for me. In fact, I think I’ll go snack on some blueberries right now!
Until next time,
1) Eric A. Johnson and Gil-Hwan An, Astaxanthin from Microbial Sources, Critical Reviews in Biotechnology, 1991, Vol. 11, No. 4, pages 297-326.
2) Paola Palozza and Norman I. Krinsky, Astaxanthin and canthaxanthin are potent antioxidants in a membrane model, Archives of Biochemistry and Biophysics, 1992, Vol. 297, Issue 2, pages 291-295.
3) Jian-Ping Yuan, Juan Peng, Kai Yin and Jiang-Hai Wang, Potential health-promoting effects of astaxanthin: A high-value carotenoid mostly from microalgae, Mol. Nutr. Food Res.,2011, Vol. 55, pages150–165.