While it is best for everyone to get essential nutrients by eating the right foods, the fact is that most Americans typically don’t consume the proper amounts of fruits and vegetables. That is why supplementation can be helpful.

Recommending Nutraceuticals

Optometrists should be encouraging a healthy diet and recommending high-quality, science-based ocular nutraceuticals to the patients who need them. These nutraceuticals should include a carotenoid called zeaxanthin, and it's selected by the retina to protect central vision. But is all zeaxanthin the same? The short answer to that question is “no.”

Types of Zeaxanthin

Some products are actually mislabeled as containing dietary zeaxanthin but are formulated to contain a zeaxanthin stereoisomer called meso-zeaxanthin. Meso-zeaxanthin is often labeled as “zeaxanthin isomers” and is actually different than dietary zeaxanthin.

Our eyes are naturally protected by macular pigment, the majority of which is made up of the carotenoids dietary zeaxanthin and lutein. The body absorbs these nutrients found in food and deposits them in the macula. Meso-zeaxanthin isn’t found naturally in the diet (unless you eat a ton of fish skin and turtle fat). Although meso-zeaxanthin is also found in macular pigment, research has shown that it is a result of the body’s natural conversion of lutein.

The Effects of the Types of Zeaxanthin

While zeaxanthin is known to be safe, the potential for unwanted effects with meso-zeaxanthin has not been evaluated yet by the scientific community. Research cannot extrapolate safety data that exist for dietary zeaxanthin and lutein to meso-zeaxanthin. Dr. Dorothy Hitchmoth OD, FAAO, who is the Chief of Optometry and Residency Director of Washington Medical Center, weighs in with her thoughts:

“It seems reasonable to wonder about untoward effects of meso-zeaxanthin use, considering it is not found naturally in the diet. In particular, I would be concerned about the implications for brain health, given that lutein is the major carotenoid in the brain and the evidence associating cognitive function with MPOD levels and the lutein level in the brain."

Hitchmoth has mentioned more research needs to be conducted in this realm.

“I have been saying for a long time that the eye is a marker for what is going on in the brain, analogous to the ‘canary in the coal mine’, and I strongly believe that we need to know more about how use of meso-zeaxanthin affects carotenoid levels in the brain.”

Learn more about what Hitchmoth and other eye care experts have to say about the difference between zeaxanthin and meso-zeaxanthin. Download the Carotenoids for Ocular Health monograph.