antioxidants and their potential prooxidative role, to
determine under which conditions supplementation with
carotenoids such as astaxanthin can help reduce skin
carcinogenesis.
Astaxanthin and inflammation
In inflammation-related clinical conditions such as
Crohn’s disease, toxic reactive oxygen species (ROS) are
released by phagocytic leucocytes at the site of inflammation
(intestinal mucosa and lumen). These, plus
increased concentrations of neutrophiles at the site of
inflammation, create a pro-oxidative balance that leads to
lower levels of antioxidant vitamins and increased levels of
markers of oxidative stress and lipid peroxidation [27].
Furthermore, oxidants have been directly linked to the
stimulation of inflammation genes in endothelial cells [28].
Similarly, ROS have been attributed an aggravating role
in the inflammation that accompanies asthma [29] and
exercise-induced muscle damage [30].
Astaxanthin was found to reduce induced swelling of rat
paw, that vitamin E did not reduce [12]. More recently,
dietary astaxanthin was found to help fight symptoms of
ulcer disease from Helicobacter pylori. Astaxanthin
reduced symptoms of gastric inflammation and was also
associated with shifts in the inflammation response [31].
Although it could be assumed that the antioxidant
properties of astaxanthin explains its anti-inflammatory
activity, further studies are needed to better understand
the specific mode of action of astaxanthin in fighting
inflammation.
Astaxanthin and heart health
High blood levels of LDL-cholesterol (the ‘bad’ cholesterol)
are associated with an increased risk of atherosclerosis.
However, HDL blood levels are inversely correlated with
coronary heart disease and are indicative of protection
against atherosclerosis. Usually LDL in plasma is not
oxidized and oxidation of LDL is believed to contribute to
the development of atherosclerosis [32] thus it might be
possible to reduce the risk of atherosclerosis by antioxidant
supplementation. Epidemiological and clinical
data indicate that dietary antioxidants might protect
against cardiovascular disease [33].
Astaxanthin is carried by VLDL, LDL and HDL in the
human blood. An in vitro test and a study with human
subjects ingesting daily dosages as low as 3.6 mg astaxanthin
per day for two consecutive weeks demonstrated
that astaxanthin protects LDL-cholesterol against
induced in vitro oxidation [34]. In an animal model
study, astaxanthin supplementation led to an increase in
blood levels of HDL [35], the form of blood cholesterol
inversely correlated with coronary heart disease. Thus,
astaxanthin could benefit heart health by modifying blood
levels of LDL and HDL cholesterol. Finally, astaxanthin
could also be beneficial to heart health by reducing
inflammation presumably associated with the development
of coronary heart disease [36].
Astaxanthin and cellular health
In the mitochondria, multiple oxidative chain reactions
generate the energy needed by the cell but produce large