Antioxidants, Eye Health and the Blood Brain Barrier

Antioxidants, Eye Health and the Blood Brain Barrier

In our previous blog on eye health,  we stated that exposure to ultraviolet light creates reactive oxygen species (ROS).  ROS is linked to age-related macular degeneration (AMD), the formation of cataracts and other eye related problems.  

Antioxidants mitigate damage from ROS. To be effective, these antioxidants have to cross the blood-brain barrier, take up residence in the eye tissue and be powerful enough to react with and neutralize ROS.

What is the Blood Brain Barrier (BBB)?

Blood circulates throughout most of our bodies, delivering nutrients to the cells, carrying out waste products to organs that filter the toxins out and carrying eicosanoids that are chemical signals that help cells communicate to each other.  Viruses and bacteria can also circulate in the blood. 

The BBB is a semipermeable border of cells that prevent certain compounds from crossing over into into the extracellular fluid and neurons that form the brain itself.  

Water, oxygen and small lipid-soluble compounds are allowed in whereas toxins, viruses and bacteria that are in the bloodstream are blocked.  Most of our eye tissue is protected by and behind the BBB.

Can antioxidants pass through the BBB?

Yes, however, note only “small lipid-soluble” compounds can pass through the BBB. Lipids are fatty acids and are not water or blood soluble.  The only way to get antioxidants through the BBB is to surround the antioxidant within a small lipid structure called a micelle or liposome. Tiny micelles carry antioxidants through the BBB and into the eye tissue.

Can all antioxidants cross the BBB?

No.  Only antioxidants that can use small lipid soluble transportation (micelles) can cross through. Lipids are fatty acids so only antioxidants that are fat soluble (i.e. hydrophobic) will form the micelles needed to get across.

Size also matters.  Natural astaxanthin that has been processed from algae using super critical carbon extraction is micron sized, much too big to form micelles and pass through the BBB.  To make micelles requires nano-sized compounds together with lipids to pass on through.

Antioxidants that dissolve in water (hydrophilic)  don’t easily cross over. Unoxidized Vitamin C is an example of an antioxidant that can’t pass through the BBB.

The list of antioxidants that cross over the BBB include astaxanthin, vitamin E, grape seed extract (proanthocyanidin), CQ10, Fisetin, Lutein, Zeaxanthin, N-acetyl carnitine, Alpha lipoic acid,  Lycopene and N-Acetyl cysteine.  All of these compounds are sold by the nutraceutical industry claiming benefits for eye health.

Do all antioxidants that cross the BBB act in the same way?

No.   Antioxidants can be classified across two different dimensions. Where do they go once they cross the BBB and once they arrive at their destination how effective they are at mitigating ROS.

The ideal antioxidant takes up residence in the cells that make up the cornea (epithelial cells, keratocytes, and endothelial cells) which is where UV induced ROS is created. 

All antioxidants have a certain capacity to mitigate ROS. Once that capacity is used up, the antioxidant is now oxidized,  falls apart and no longer protects the eye from ROS damage.  In 2010,  FDA rated the oxidation reduction capacity (ORAC) of each antioxidant. 

What is the best antioxidant for eye health?

The ideal antioxidant for eye health is astaxanthin.

Astaxanthin is nature’s most powerful antioxidant.  Its oxidation reduction capacity is 5000X higher than vitamin C,  800X higher than CQ10 and 75X more powerful than alpha lipoic acid. More importantly, it takes up residence exactly where it is needed, in the cell plasma membrane of the cells that form the cornea.

 

Adjuvia™  Astaxanthin

Adjuvia Astaxanthin the best antioxidant for eye health. To pass though the BBB requires small lipid-soluble compounds.  Our patented process uses astaxanthin derived from freshwater algae to make astaxanthin really small (about 40 nanometers).  We retain all of the lipids in the algae to form the micelles needed to carry astaxanthin through the BBB and into the cornea.