The various steps of digestion, absorption, and plasma transport of dietary carotenoids in mammals were reviewed by Furr and Clark in 1997 in “Intestinal Absorption and Tissue Distribution of Carotenoids”. J. Nutr. Biochem. 8, 364-377.

In the plasma, oil-soluble carotenoids such as beta- and alpha-carotene or lycopene, are mostly transported by very low-density lipoproteins (VLDLs) and low-density lipoproteins (LDLs), while more polar carotenoids, such as astaxanthin, zeaxanthin, or lutein, are more likely to be transported by LDLs and high-density lipoproteins (HDLs).

A quite elegant study on humans conducted by Osterlie et al. confirmed the bioavailability of astaxanthin supplied in a single high dosage of 100 mg, and
its transport in the plasma by lipoproteins. The results indicate that a selective process increases the relative proportion of astaxanthin Z-isomers compared to the all-E-astaxanthin during blood uptake, and that astaxanthin E/Z isomers have similar pharmacokinetics.

Fuji Chemicals published in one of their astaxanthin brochures that only the free form of astaxanthin is detected in the blood, and it can reach a maximum concentration of 210-230 ng/ml. Interestingly, they found that a single dose of 50 mg of astaxanthin—or 12 mg per day—showed similar peak concentrations in the blood plasma.

Takahashi et al. studied the distribution of astaxanthin in tissues and plasma lipoproteins in male broiler chickens fed with astaxanthin from Phaffia rhodozyma.
More than 70% of the astaxanthin was contained in the high-density lipoprotein (HDL) fraction of the plasma, and astaxanthin concentration in the small intestine was highest, followed by subcutaneous fat, abdominal fat, spleen, liver, heart, kidney, and skin. The lowest concentration was in the muscles. Over 50% of astaxanthin deposited in liver tissues was detected in the microsomal fraction, and 15% was in the mitochondrial fraction. In muscles, both fractions of mitochondria and sarcoplasmic reticulum contained astaxanthin.

Showalter et al. studied the plasma and tissue accumulation of non-esterified, free astaxanthin in mice after oral dosing of a disodium disuccinate diester of astaxanthin (Heptax trademark). The disodium disuccinate diester of astaxanthin (Heptax trademark) was administered by oral gavages in a lipophilic emulsion to C57BL/6 mice, and plasma appearance and tissue accumulation of non-esterified, free astaxanthin was studied by HPLC over 72 hours after single- and multiple-dose regimens. The results suggest that hepatoprotection against oxidative insults may be achieved after a single dose of Heptax in mice.

Chew et al. compared the anti-cancer activities of dietary beta-carotene, canthaxanthin, and astaxanthin in mice in vivo, and found that concentrations of plasma astaxanthin (20 to 28 mumol/L) were greater than that of beta-carotene (0.1 to 0.2 mumol/L) and canthaxanthin (3 to 6 mmol/L). However, in tumor tissues, the concentration of canthaxanthin (4.9 to 6.0 nmol/g) was higher than that of beta-carotene (0.2 to 0.5 nmol/g) and astaxanthin (1.2 to 2.7 nmol/g). In general, all three carotenoids decreased mammary tumor volume. Mammary tumor growth inhibition by astaxanthin was dose-dependent and was higher than that of canthaxanthin and beta-carotene. Lipid peroxidation activity in tumors was lower (P < 0.05) in mice fed 0.4% astaxanthin, but not in those fed beta-carotene and canthaxanthin. The researchers concluded that beta-carotene, canthaxanthin, and especially astaxanthin inhibit the growth of mammary tumors in mice; their anti-tumor activity is also affected by the supplemental dose.

Osterlie et al also studied the accumulation of astaxanthin geometrical and optical isomers in rainbow trout and found that geometrical and optical isomers of astaxanthin are distributed selectively in various tissues of rainbow trout.

Several recent studies clearly showed the positive effect of astaxanthin esters mixed with fat formulations on the oral bioavailability of astaxanthin in humans.

Odeberg et al. found that astaxanthin bioavailability could be enhanced in the presence of fat. In an open parallel study, healthy male volunteers received a single dose of 40 mg astaxanthin in the form of lipid-based formulations or as a commercially available food supplement, followed by blood sampling for further analysis of plasma concentrations. The highest bioavailability was observed with formulations containing a high content of the hydrophilic synthetic surfactant polysorbate 80.

Clark et al. compared lycopene and astaxanthin absorption from corn oil and olive oil emulsions in rats. Absorption of lycopene and astaxanthin from both oils increased with the amount infused into the rat’s duodenum. The average recovery of astaxanthin in the lymph from the olive oil emulsion was 20%, but decreased to 13% from emulsions containing corn oil. Lycopene was not as well absorbed as astaxanthin. The average recovery of LYC was 6% from olive oil emulsions but only 2.5% when infused with corn oil. They concluded that the type of oil with which a carotenoid is consumed can substantially influence its absorption.

Astaxanthin, a superb natural antioxidant

Information provided in this article is for informational purposes only, and is not meant to substitute for the advice of your own physician or other medical professional.
The statements herein have not been evaluated by the Food and Drug Administration. Astaxanthin from Algatech is not intended to diagnose, cure, treat, or prevent any disease.