Friday, January 21, 2011
Thanks to the unbridled passion for zeaxanthin science of our friend and fellow member/supporter of the Ocular Nutrition Society and the Council for Responsible Nutrition, Dennis Gierhart, PhD, the ophthalmic community better understands the important role that zeaxanthin plays in neural tissue health.
Supplementing with zeaxanthin has been suggested in a number
of clinical studies to lower the risk of diseases associated with aging,
including macular degeneration and cataract. Science also suggests that
zeaxanthin can efficiently inhibit diabetes-induced lipid peroxidation
in the retina.
We have known for a number of years that
zeaxanthin protects the eye from ultraviolet and blue-light damage.
Zeaxanthin's ability to absorb blue light was recently found to make
night driving easier for older adults who participated in a
carotenoid study that looked at supplementation with lutein
and zeaxanthin; lutein alone, and zeaxanthin alone.
Zeaxanthin and lutein are the two carotenoids
responsible for the macula pigment, with zeaxanthin being in the very
center of the macula. Both nutrients are included in two arms of the
AREDs2 study: 10 mg of lutein and 2 mg of zeaxanthin. However, the
amount of zeaxanthin included is less than optimal, given the very
promising research that supports higher dosage of zeaxanthin to
be beneficial for a number of diseases of the eye.
A research study published in Investigative Ophthalmology and Visual Science (IOVS),
suggests that zeaxanthin supplementation prevented diabetes-induced
increase in retinal damage, and it prevented increases in vascular
endothelial growth factor (VEGF), and intercellular adhesion molecule
Diabetic retinopathy is considered to be a
multifactorial disease with various abnormalities contributing to its
development. It is the major cause of blindness in young adults. VEGF,
a major angiogenic factor is elevated in the retina and vitreous of
diabetic patients and animals, and this increase is associated with the
manifestation of diabetic retinopathy.
Oxidative stress is always increased in the retina in diabetes; the antioxidant defense system is compromised, and superoxide levels are elevated in the
mitochondria. Increased oxidative stress is one of the key regulators
in the development of diabetic complications. Antioxidants are
suggested to prevent diabetes-induced oxidative stress and the development of retinopathy in research animals and people.
Diabetics have lower serum levels of the
xanthophyll carotenoids, zeaxanthin and lutein, and they also seem to
have lower serum levels of the hydrocarbon carotenoid, lycopene.
Their retinal levels of zeaxanthin and lutein are also decreased.
Zeaxanthin is generally considered a safe
supplement (GRAS). Although Zeaxanthin is available from a few foods
including corn, egg yolks, paprika, oranges and green vegetables, the
daily consumption is far lower than the concentration necessary for
ocular/neural tissue protection.
Ellen Troyer, MT MA
Biosyntrx CEO / Chief Research Officer