Elizabeth Johnson, Ph.D., scientist II in the Carotenoids and Health Laboratory at Tufts University, is an expert on lutein, the antioxidant that supports prevention (or delay) of age-related eye diseases. Get a sneak peek into her topic before she presents at Nutracon 2011 in the healthy aging track on "The Role of Lutein in Neural Health – from the Retina to the Brain."
Fi: How big a part of "healthy aging" is eye health?
EJ: Very big. When you think about it, the eye is unlike the heart, bones or most other organs and tissues in that it is particularly vulnerable to light damage. So imagine what happens after years, decades of light exposure (think of a salad sitting in the summer sun), which cause oxidative damage. That's where lutein comes in. Lutein is an antioxidant found in the parts of the eye that are vulnerable to decades of light exposure: the lens and retina. In fact, the leading causes of visual impairment in the United States are age-related cataract and macular degeneration. Having a healthy diet that contains a good amount of lutein helps in the prevention or delay in progression of these major diseases.
Fi: What makes lutein different from other carotenoids such as beta-carotene or zeaxanthin?
EJ: There are over 600 carotenoids naturally found in nature (think of the reds, oranges and yellows in the New England fall). We consume about 50 in our diet and about 20-30 are found in our blood and tissues, but only lutein and its sister compound, zeaxanthin, are found in the lens and retina.
Fi: So, is lutein the most superior of the carotenoids or xanthophylls?
EJ: Well that's hard to say. Usually you find lutein where you find zeaxanthin and vice versa, so it's really hard to tease apart whether one is more important than the other. Right now, NIA [National Institute on Aging] is conducting a large placebo-controlled intervention trial that looks at progression of age-related macular degeneration and the effect that supplementation with both lutein and zeaxanthin may have.
Fi: Bilberry has long been thought of as being the top botanical for eye health, dating back to WWII British pilots. Is there any scientific validity to bilberry?
EJ: The jury is still out on the effectiveness of bilberry on eye health (including visual acuity). There have been a number of studies but, unfortunately, they are either case studies (which claim benefit) or controlled studies in healthy young Navy Seals that show no improvement. But how can you improve on perfect vision? For a comprehensive review on this see: Canter PH, Ernst E. Anthocyanosides of vaccinium myrtillus (bilberry) for night vision – a systematic review of placebo-controlled trials. Survey of Ophthalmology 2004;49:38-50.
Fi: What's the most compelling piece of research to back lutein's efficacy for eye health?
EJ: There are actually many different kinds of evidence, which only lends to the credibility of the role of lutein in eye health. These include cell culture, animal, clinical and epidemiological studies.
Cell culture and animal studies help in evaluating the mechanisms by which lutein may be protective. Clinical trials that use lutein as an intervention have found it to improve visual function. Epidemiological studies have found that those who have high intakes of dietary lutein tend to be at a decreased risk for cataracts and age-related macular degeneration [AMD].
The real answer may come after the completion of a current double-blind, placebo-controlled trial on about 4,000 patients with intermediate AMD. This is being conducted at the National Eye Institute of the National Institute of Health (NIH). The study will be completed in 2012. Lutein, with or without the omega-3 fatty acids, is being tested for its effectiveness in slowing down the progression of AMD.
Fi: Can you get therapeutic quantities of lutein in foods, or are supplements the way to go?
EJ: Yes, the levels that have been found to be protective in epidemiologic studies is about 6mg/day, which is easily attained with a diet high in fruits and vegetables. For example, 2oz. of cooked spinach (one of the best sources of lutein) contains about 6-10mg. The amount used in the NIH study is 10 mg/d lutein and 2 mg/d zeaxanthin.
Fi: What are some other health benefits of lutein? For example, how compelling is the research on cardiovascular health?
EJ: There are studies that have looked at that. Being an antioxidant, it's thought to play a role in prevention of heart disease because oxidative damage, again, is thought to be positive in heart disease. It's not completely clear what lutein is doing in those cases, and it may be serving as a biomarker of a diet that's high in fruits and vegetables.
Fi: Lutein in skin health seems to be a trend. Is this a new arena for lutein?
EJ: It is. Nutrition is really thought to be important as far as skin health. Like the eye, the skin is particularly vulnerable to light damage. You do find lutein in the skin where it may be protecting against light damage due to its role as an antioxidant.
Fi: On a more personal note, what supplements do you take?
EJ: Because I'm an older female and I'm worried about bone loss, I take my calcium and vitamin D. I just want to hedge my bet against bone loss. And I do take my fish oils, just to ensure I'm getting enough, because fish oil has been found to be protective against eye disease, brain disease and heart disease.
Nutracon Highlights: Healthy Aging Track
Track chairs: Tom Aarts, president, Nutrition Business Advisors and Tim Avila, founder and CEO, Systems Bioscience Inc.
Keep your eyes peeled for a variety of healthy aging ingredient discussions in this track at Nutracon 2011. Nutracon is March 9-10, 2011, in Anaheim, Calif., co-located with SupplyExpo and Natural Products Expo West. Topics beyond lutein include:
- Steve Walton on lifelong aging. Walton, general manager of Health Focus International, reminds us that aging occurs from birth, and isn’t just for the over 50 crowd. Attend his session to learn about different consumer opportunities that you can take advantage of in your product development efforts.
- Patrick Rea on healthy aging treads. Rea is publisher of Nutrition Business Journal.
- David Mark, Ph.D., on polyphenols. Mark raises an interesting question – and answers it – in his session, "The Polyphenol Paradox – If Not Antioxidants, What?"
- Robert Heaney, MD, on Vitamin D. Examine the latest scientific developments in vitamin D and bone health with Heaney, of Creighton University.
- J. Michael Wyss, Ph.D., on botanicals. Wondering what role botanicals play in healthy aging? Professor J. Michael Wyss of the University of Alabama School of Medicine talks about "Sugar, Salt, Sex and the Potential of an Entwining Vine."