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.