The test, developed by Canadian company Arctic Diagnostics (ArcticDX), is called Vita Risk. The name plays off of another diagnostic test offered by the company called Macula Risk, which assess a patients overall risk of AMD based on their genetics. The Vita Risk test also purports to determine which patients might be harmed by eye health supplements.
“Vita Risk is a genetics-based adjunct to treatment for age-related macular degeneration (AMD). Patients with dry AMD are commonly treated with eye vitamins and supplements to prevent advanced disease and vision loss. Based on personal genetics, some patients derive no benefit and may even be harmed by this treatment, while others benefit greatly,” said Greg Hines, president and CEO of ArcticDx. “Vita Risk determines which eye vitamin formulation an individual should take to maximize benefit and avoid needless progression to blindness.”
The treatment of AMD is one of those rare areas in which conventionally trained health care practitioners are fully on board with dietary supplementation. Two large scale studies — AREDS and AREDS 2 — have looked at which supplement ingredients could best combat the progression of macular degeneration. The current research points to a formula containing lutein, zeaxanthin, vitamin E and zinc.
James Stringham, PhD, is an expert on the role of carotenoids in the retina. An experimental psychologist by training, Stringham has concentrated on the effects of visual acuity as a factor in cognitive performance. Stringham, who is now a research scientist at the University of Georgia, has in the past studied visual performance and the role carotenoids play in other career stops including a stint as senior vision scientist at the Air Force Research Laboratory.
“I started studying visual perception which of course involves the brain,”Stringham told NutraIngredients-USA. “Along the way I have become something of a neuroscientist.”
On the question of risk
Stringham said it is true that a small percentage of people seem to lack the dedicated transporter that carries the carotenoids into the retina and so do not benefit from supplementation nearly as well as the others. As far as the test could elucidate that, it would be good information to have.
“It is valuable information. I would want to know. You would then know if you are going to respond optimally to these supplements. We have found that 4% or 5% of people appear to have difficulty transporting the nutrients from the blood to the eye. We are still trying to figure out what’s going on with that situation and it is possibly genetic,”he said.
But Stringham said he was uncomfortable with the notion of the ‘riskiness’ of dietary supplementation in relation to eye health. He said in his opinion this has mostly to do with the inclusion of zinc into the supplement formula. The original optimal level, determined in the AREDS2 trial, was pegged at 80 mg, but was subsequently lowered to a 25 mg dose.
“I think the idea of ‘risk’ is mostly about zinc. Zinc plays an important role in the transport of certain pigments into the retina, but there is a possibility for zinc to build to toxic levels in the body. Zinc toxicity first manifests as an upset stomach and it can interfere with copper absorption,” he said.
“But in the kind of research I do, on the nutrients lutein and zeaxanthin, there is really no reasonable toxic dose on these nutrients and in the research done around the world there have been no adverse events. So there is really no risk associated with these, and even if you are a ‘low responder’ you still get the systemic benefits of these antioxidants in your body. There is no evidence for the notion that by taking a supplement you could exacerbate the disease,” Stringham said.
OmniActive Health Technologies, a prominent supplier of both lutein and zeaxanthin, had this to say via a statement supplied to NutraIngredients-USA: “Supplementation studies on eye health have consistently shown benefits including preventing and/or slowing down the progression of age-related vision loss, and supporting overall visual function. Although this test could provide some indication as to where a consumer may stand on the ‘responder’ spectrum, the fact remains that there are nutrients, like the macular carotenoids, that are essential for visual health and function. Dietary intake or supplementation is the only way to get these nutrients.”
Concentration of carotenoids
Many researchers in the field of dietary ingredients start out with the compounds themselves, looking at traditional uses and trying to build up a picture that conforms to Western scientific methods of their modes of action and activities in the body. Stringham worked the other way, so to speak, starting with the obvious and profound concentration of these carotenoids in the eye and working backward to fill in the blanks as to why there are there.
“That led me into nutrition as well,” Stringham said. Studying these xanthophyll carotenoids led Stringham to a revelation; of all the well researched dietary ingredients, such as omega-3s and vitamin D3, lutein, zeaxanthin and meso-zeaxanthin stand alone in terms of the concentration at one site. Like those other dietary ingredients these carotenoids, especially lutein, can be found in many tissues, too, but their prevalence in the retina really stands apart.
“It is the highest concentration of any nutrient that the body takes in in any tissue in the body,” Stringham said.