Lutein, a chemical found in green vegetables, is a member of a family of substances known as
carotenoids
.
Beta-carotene
is the most famous nutrient in this class. Like beta-carotene, lutein is an
antioxidant
that protects our cells against damage caused by dangerous, naturally occurring chemicals known as free radicals.
Recent evidence has found that lutein may play an important role in protecting our eyes and eyesight. It may work in two ways: by acting directly as a kind of natural sunblock, and also by neutralizing free radicals that can damage the eye.
Sources
Lutein is not an essential nutrient. However, it is possible that it may be useful for optimal health.
Green vegetables are the best source of lutein, especially spinach, kale, collard greens, romaine lettuce, leeks, and peas. Unlike beta-carotene, lutein is
not
found in high concentrations in yellow and orange vegetables such as carrots.
We don't know how much lutein is necessary for a therapeutic effect, but estimates range from 5 to 30 mg daily. (However, see
Safety Issues
)
Therapeutic Uses
According to theoretical findings and two preliminary double-blind studies, it appears that use of lutein supplements might help prevent or slow the development of
age-related macular degeneration
(ARMD) and possibly
cataracts
, the two most common causes of vision loss in seniors.
Lutein has also shown a hint of promise for treatment of
retinitis pigmentosa
, an inherited form of eye disease that causes progressive vision loss.
13
Very weak evidence hints that lutein might help prevent
atherosclerosis
.
9
What is the Scientific Evidence for Lutein?
Most but not all
observational
studies suggest that people who eat foods containing lutein are less likely to develop cataracts and perhaps macular degeneration as well, the two most common causes of vision loss in adults.
1–5,8
Furthermore, there are good theoretical reasons to believe that lutein may play an important role in protecting the eyes.
Lutein is the main pigment (coloring chemical) in the center of the retina, the region of maximum visual sensitivity known as the
macula
. Macular degeneration consists of injury to the macula and leads to a severe loss in vision. One of the main causes of macular degeneration appears to be sun damage to the sensitive tissue. Lutein appears to act as a natural eyeshade, protecting the retina against too much light.
6
It is also an
antioxidant
, meaning that it fights dangerous, naturally occurring substances called free radicals. Free radicals may play a role in macular degeneration.
Based on this information, researchers conducted a
double-blind, placebo-controlled
trial of lutein.
11
The study enrolled 90 people with dry-type macular degeneration and followed them for 12 months. The participants received either lutein (10 mg), lutein plus other antioxidants, and a multivitamin/mineral supplement, or placebo. At the end of the study period, participants who had taken lutein alone or lutein plus the other nutrients showed improvements in vision, while no change in vision was seen in the placebo group.
A subsequent study failed to find benefit with lutein, but it used a lower dose (6 mg daily) and involved fewer people.
15
Ultimately, further study will be needed to establish whether lutein is actually helpful for macular degeneration.
Besides protecting the macula, lutein might also shield the lens of the eye from light damage, slowing the development of
cataracts
.
7
One small 2-year, double-blind, placebo-controlled trial found some evidence that lutein may improve vision in people who already have cataracts.
10
Safety Issues
Although lutein is a normal part of the diet, there has not been much evaluation of lutein's safety when taken as a concentrated supplement.One study found evidence that lutein is safe in doses up to the highest tested dose of10 mg daily.
14
A review of other evidence concluded that long term use of lutein should be safe when taken at a dose of up to 20 mg per day.
13
Maximum safe dosages for young children, pregnant or nursing women, or those with severe liver or kidney disease have not been established.
References
1:
Mares-Perlman JA, Brady WE, Klein BE, et al. Diet and nuclear lens opacities.
Am J Epidemiol
. 1995;141:322–334.
2:
Hankinson SE, Stampfer MJ, Seddon JM, et al. Nutrient intake and cataract extraction in women: a prospective study.
BMJ
. 1992;305:335–339.
3:
Brown L, Rimm EB, Seddon JM, et al. A prospective study of carotenoid intake and risk of cataract extraction in US men.
Am J Clin Nutr.
1999;70:517–521.
4:
Chasan-Taber L, Willett WC, Weddon JM, et al. A prospective study of carotenoid and vitamin A intakes and risk of cataract extraction in US women.
Am J Clin Nutr.
1999;70:509–516.
5:
Landrum JT, Bone RA, Kilburn MD. The macular pigment: a possible role in protection from age-related macular degeneration.
Adv Pharmacol
. 1997;38:537–556.
6:
Landrum JT, Bone RA, Kilburn MD. The macular pigment: a possible role in protection from age-related macular degeneration.
Adv Pharmacol
. 1997;38:537–556.
7:
Hammond BR Jr, Wooten BR, Snodderly DM. Density of the human crystalline lens is related to the macular pigment carotenoids, lutein and zeaxanthin.
Optom Vis Sci
. 1997;74:499–504.
8:
Mares-Perlman JA, Fisher AI, Klein R, et al. Lutein and zeaxanthin in the diet and serum and their relation to age-related maculopathy in the third National Health and Nutrition Examination Survey.
Am J Epidemiol.
2001;153:424–432.
9:
Hassan K, Hough G, Wang X, et al. Dietary lutein markedly reduces atherosclerotic lesion formation in apolipoprotein null mouse [abstract].
FASEB J.
1999;13:A176.
10:
Olmedilla B, Granado F, Blanco I, et al. Lutein, but not alpha-tocopherol, supplementation improves visual function in patients with age-related cataracts: a 2-y double-blind, placebo-controlled pilot study.
Nutrition
. 2003;19:21–24.
11:
Richer S, Stiles W, Statkute L, et al. Double-masked, placebo-controlled, randomized trial of lutein and antioxidant supplementation in the intervention of atrophic age-related macular degeneration: the Veterans LAST study (Lutein Antioxidant Supplementation Trial).
Optometry
. 2004;75:216-30.
12:
Shao A, Hathcock JN. Risk assessment for the carotenoids lutein and lycopene.
Regul Toxicol Pharmacol.
2006;45:289-98.
13:
Bahrami H, Melia M, Dagnelie G et al. Lutein supplementation in retinitis pigmentosa: PC-based vision assessment in a randomized double-masked placebo-controlled clinical trial [NCT00029289].
BMC Ophthalmol.
2006 Jun 7 [Epub ahead of print].
14:
Rosenthal JM, Kim J, de Monastario F et al. Dose-ranging study of lutein supplementation in persons aged 60 years or older. Invest Ophthalmol Vis Sci. 2006;47:5227-33.
15:
Bartlett HE, Eperjesi F. Effect of lutein and antioxidant dietary supplementation on contrast sensitivity in age-related macular disease: a randomized controlled trial. Eur J Clin Nutr. 2007 Jan 31 [Epub ahead of print]
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
