Aging Baby Boomers Devoting Nutrition and Money to Maintain Eye Health
Nutritionís role in eye health has become a topic of conversation, no doubt correlating at least somewhat with the aging of the baby boomers.
By Winston Boyd, Ph.D., and David Feder, R.D. | 08/06/2008
It is believed the natural aging process with its attendance oxidative stresses plays the major role in the progressive degeneration of vision as we age. And with the increase in rates of obesity and the resulting increased incidence of type-2 diabetes comes another eye health issue: diabetic retinopathy.
We now hear regular reference to the term Age-Related Macular Degeneration (AMD). Cataracts have been and remain an issue of concern, especially for older people. While age plays an important role in eye health, recent medical research points to weight maintenance, micronutrient deficiency, macronutrient excess and cardiovascular disease as burgeoning causes of poor eye health.
However, it has only been in recent years the roles of diet and overall health have been investigated.
The vision thing
While maintaining the health of the cornea, lens, retina and optic nerve are critical, one area of the eye appears to be closely connected to the quality of eyesight as we age. This area, just behind the retina and associated with the connection between the optic nerve and the eye, is the macula.
Critical to the macula are carotenoid compounds, including vitamin A and beta-carotene, as well as lycopene, lutein and zeaxanthin. These compounds are oil-soluble but, through breakthroughs in microencapsulation, are now able to be effectively included in food and drink formulations, although they do impart color. They are found naturally in dark green leafy vegetables, such as spinach and kale, as well as in deep orange and red foods, such as paprika or berries.
“Americans continue to be deficient in fruits and vegetables, which are the major source of these nutrients critical to the healthy functioning of the eye,” says David Turok, M.D., an ophthalmic surgeon in the Chicago area. “Vitamin A deficiency remains one of the top causes of blindness in the world. The Age-Related Eye Disease Study (AREDS) — a major prospective study involving multiple universities — showed the vital role of micronutrients in retarding the progression of macular degeneration, the leading cause of blindness in older Americans,” emphasizes Turok.
Certain proteins in the macula appear to degrade over time, apparently at least partly in response the effects of strong light and other pro-oxidative stresses. The degraded proteins form deposits that interfere with vision.
The two main carotenoids found in the eye, lutein and zeaxanthin, accumulate in the macula. Current theory is that the presence of these specific carotenoid antioxidants in the macula may inhibit the oxidative processes that lead to macular protein degradation.
Carotenoids — beyond beta-carotene
Kalsec Inc. (www.kalsec.com), Kalamazoo, Mich., makes ZeaGold, a natural, highly bioavailable esterification of zeaxanthin from paprika. It’s GRAS and exempt from color certification in the U.S. and may be used as a nutrient while also imparting color. It’s available in a 3 percent or 10 percent concentration. The company also will soon market a 5 percent beadlet.
Parsippany, N.J.-based DSM Nutritional Products’ (www.optisharp.com) Optisharp brand of zeaxanthin is being used to great success in powdered drink mixes in Asia and even in soup mixes in South America. The company also makes a number of vitamin A ingredients such as beta-carotene, lycopene and lutein for eye health formulations.
Since the carotenoids act as colorants, their use so far occurs mostly in bars and colored beverages. Coca Cola Co.’s Glaceau touts its Focus Vitaminwater flavor, with vitamin A (and ginkgo biloba), as helping to maintain eye health. Minneapolis-based Ardea Beverage Co. (www.nutrisoda.com), maker of functional carbonated beverages, is about to launch its newest flavor, Vision, a kiwi-clementine-flavored beverage with lutein and zeaxanthine.
San Joaquin Valley Concentrates (www.activin.com), Fresno, Calif., offers ActiVin brand of oligomeric proanthocyanidin (OPC), a polyphenolic bioflavanoid derived from grape seeds. OPCs are powerful antioxidants that were studied for their protective effect against cancer and heart disease but which also have shown to be powerfully protective against cataracts.
Kemin Health LC (www.kemin.com), Des Moines, provides Floraglo, its highly purified lutein for food and beverage applications derived from marigold flowers. Eggs from chickens fed with such marigold extracts as feed fortification provide a good source of bioavailable lutein.
A number of other ingredient companies have been taking the lead in providing commercial forms of naturally derived or synthetic (although nature-identical) lutein.
Perhaps the most significant recent news in eye health is the effect key eye carotenoids have on younger people.
“The results of a recent University of Georgia study conducted on healthy young adults aged 17-41 and published in Optometry and Vision Science showed supplementation with a combination of 10mg lutein and 2mg of zeaxanthin over six months increased macular pigment optical density (MPOD) as early as 60 days following supplementation and throughout the study period,” says Richard Roberts, Ph.D., principal manager of scientific affairs and technical services for Kemin.
Roberts adds that the increase in MPOD “correlated with a reduction in glare disability and photostress recovery time.” This means persons supplementing with lutein and zeaxanthin could discriminate between objects more readily under glaring-light situations while simultaneously exhibiting more rapid recovery following exposure to bright light sources, such as sunlight or bright headlights.
“Although similar effects have been shown in early-stage AMD patients and people with cataracts, this study is the first to show these effects in younger, healthy subjects,” Roberts says. “Given the importance accuracy of vision plays, especially while driving during a bright day or at night exposed to bright headlight glare, these data continue to support the health benefits of lutein and zeaxanthin in our daily diet throughout everyone's lifetime.”
New ingredients for eye health
Only recently a form of zeaxanthin called meso-zeaxanthin has been identified in close association with lutein and zeaxanthin in the eye. The compound appears to be rare in nature and is thought to be produced in the eye by conversion of lutein. It shows significant promise as a new eye health ingredient, but more research is needed and it currently only is included in supplements.
Astaxanthin could prove one of the up and coming ingredients for eye health. It's a potent antioxidant, recognized to be about 500 times more effective than vitamin E and much more powerful than other carotenoids such as lutein, lycopene and beta-carotene.
Algatechnologies grows microalgae that make astaxanthine. When exposed to high-intensity light, the microalgae produce astaxanthin as a protective agent.
"There is substantial evidence astaxanthin may help keep vision sharper and keep eyes healthier when they are exposed to the damaging UV rays in everyday sunshine," says Efrat Kat, marketing manager for Algatechnologies Ltd. (www.algatech.com), Hevel Eilot, Israel.
Astaxanthin seems to target eye tissues particularly well. "Any compound functioning in the eye must be able to cross not only the blood-brain barrier but also the blood-retinal barrier to gain access into the eye," explains Kat. "Among all antioxidants -- and specifically carotenoids -- astaxanthin appears to easily penetrate these two barriers, thanks to its low molecular weight and its specific chemical structure."
Kat cites a double-blind study performed in Japan wherein, after four weeks of supplementation with a daily dose of 5mg astaxanthin, researchers reported a 46 percent reduction in the number of subjects complaining of eyestrain. "Researchers also found positive effects at 4mg astaxanthin per day in relieving eye fatigue," adds Kat.
Algatechnologies supplies AstaPure natural astaxanthin. The compound is derived from Haematococcus pluvialis microalgae. The microalgae, when exposed to high-intensity light, produce astaxanthin as a protective agent. Algatechnologies uses a patented, closed and environmentally protected cultivation system, which allows the production of a pure astaxanthin product free of any biological or chemical contamination.
AstaPure currently is approved for use as a dietary supplement and for cosmetics in the U.S. In Japan it is approved for food and beverages, and it just received European Union Novel Foods approval in July this year. Algatechnologies is seeking to expand regulatory approvals for AstaPure to allow its use in food and beverages in the U.S.
The AstaPure line includes a 10 percent astaxanthin oleoresin extracted using super-critical CO2 extraction technology; gelatin-free vegetarian 2.5 percent astaxanthin beadlets; and cold water dispersible beadlets.
From micro to macro
Some of the best sources of anthocyanins and carotenoids are macroingredients. Blueberries and other red, purple and orange fruits and vegetables have a long historic connection to eye health.
Two examples considered new only by their recent trendiness are goji berries and açai. Bilberries, considered a folk cure for poor night vision in Europe for years, also are catching the eye of processors in the EU and Asia for eye health-targeted products.
As stars of the recent superfruit explosion, goji berries and açai have been recognized for their health benefits as protectors against cancer and heart disease. Now, with formidable concentrations of anthocyanins and carotenoids, they’re enjoying attention for their eye health benefits as well. Look for all the goji- and açai-containing cereals, bars and beverages that have been popping up to start including vision health as marketed benefit soon.
Zinc, selenium and omega-3s also are showing promise in research for eye health. Also, there are a number of other known nutraceuticals enjoying re-examination for protective qualities regarding vision and aging of eyes. Processors will find it worth keeping a sharp eye on this trend in the coming years.