How It Works
Bottom Line: Lutein may prevent worsening of macular degeneration.
Lutein is a natural pigment synthesized by plants and microorganisms. It is known to be an antioxidant, to which its proposed cancer prevention activity is attributed. Scientists also propose that lutein may stimulate the immune system, inhibit DNA mutation, or inhibit growth of pre-cancerous cells. Lutein has been associated with a decreased risk of macular degeneration and cataracts, although researchers are uncertain how lutein exerts this effect. In addition, studies in animals and human subjects have shown that high lutein intake can prevent the progression of atherosclerosis.
Purported Uses
As an antioxidant
Laboratory and clinical data support this use.
To prevent cancer
One population-based study showed that higher intake of foods rich in lutein is associated with a lowered risk of developing colon cancer. But another study showed increased risk of lung cancer among smokers. More research is needed.
To treat cataracts
No scientific evidence supports this use.
To prevent and treat macular degeneration
A few clinical trials support this use.
For increased visual acuity
Clinical trials support this use in patients with degenerative diseases of the retina.
Research Evidence
Retinitis pigmentosa or macular degeneration:
A small study evaluated the use of lutein supplements by recruiting subjects with retinitis pigmentosa or macular degeneration via the Internet. Sixteen patients took 40 mg of lutein daily for nine weeks, followed by 20 mg daily for 17 weeks. Ten patients also took DHA. Every two weeks, patients performed a self-evaluation of visual acuity, and overall, reported eyesight improvements after beginning lutein supplementation. Effects were strongest in individuals with blue eyes. The results from this study are not very reliable due to the fact that several patients took DHA, vitamin B complex, digestive enzymes, vitamin A and/or beta-carotene in combination with their lutein therapy, making it unclear whether the positive effects were a result of the lutein or these other supplements.
Prevention of colon cancer:
In a large population-based study, researchers collected data from 1993 patients with adenocarcinoma of the colon and 2410 healthy control subjects to compare the intake of dietary antioxidants and the risk of colon cancer. Patients who reported a higher intake of foods containing lutein (such as spinach, broccoli, lettuce, tomatoes, oranges and orange juice, carrots, and celery) were found to have a significantly lower risk of developing colon cancer.
Warnings
This product is regulated by the FDA as a dietary supplement. Unlike approved drugs, supplements are not required to be manufactured under specific standardized conditions. This product may not contain the labeled amount or may be contaminated. In addition, it may not have been tested for safety or effectiveness.
Side Effects
No side effects have been reported at normal doses.
Toxicity from high lutein intake can cause carotenodermia, a yellowish discoloration of the skin.
Common Name
Xanthophyll, dihyroxycarotenoid, nonprovitamin A carotenoid
Clinical Summary
A natural pigment synthesized by plants and microorganisms. Lutein is used primarily as an antioxidant and also to prevent and treat cancer, heart disease, and macular degeneration. Lutein has antioxidant activity (2) and is classified as a nonprovitamin A carotenoid, which also includes lycopene and zeaxanthin. Alpha-carotene, beta-carotene, and beta-cryptoxanthin are classified as provitamin A carotenoids because they can be converted into retinol. Epidemiologic studies suggest an inverse relationship between increased lutein consumption and decreased incidence of atherosclerosis (6), possibly colon cancer (7), and macular degeneration (9). However, conclusions from a systematic review and meta-analysis suggest that the current evidence is insufficient to support use of lutein and other dietary antioxidants in prevention of early age related macular degeneration (10). Further, long-term supplementation with beta-carotene, retinol, and lutein supplements was associated with an increased risk of lung cancer (11).
No significant adverse effects or drug interactions have been reported with use of lutein.
Food Sources
Kale, spinach, winter squash, cruciferous vegetables, cabbage, green beans, yellow/orange fruits, mangoes, papayas, peaches, oranges
(2)
Purported uses
Cancer prevention
Cataracts
Macular degeneration
Visual acuity
Mechanism of Action
Lutein is a natural pigment synthesized by plants and microorganisms. Lutein has been associated with a decreased risk of macular degeneration and cataracts
(1). The physiologic function of lutein in the macular membranes is not known at this time
(3). Referred to as a nonprovitamin A carotenoid, it is not known to have any vitamin A activity. Other possible actions for carotenoids are antioxidant
(2), immunoenhancement, inhibition of mutagenesis and transformation, and inhibition of premalignant lesions. Lutein has been associated with decreased risk of colon cancer
(7) and atherosclerosis
(6).
Pharmacokinetics
Absorption:Intestinal absorption of carotenoids, including lutein, is facilitated by the formation of bile acid micelles containing carotenoids. The presence of fat in the small intestine stimulates the secretion of bile acids from the gall bladder and improves the absorption of carotenoids by increasing the size and stability of the micelles, thus allowing more carotenoids to be solubilized. Bioavailability of lutein is affected by the dose and presence of other carotenoids such as Beta carotene. The bioavailability of lutein from vegetables is approximately 70%
(3).
Distribution:The concentrations of various carotenoids in human serum and tissues are highly variable and depend on food sources, efficiency of absorption, and amount of fat in the diet. Lutein is transported by high-density lipoprotein (HDL) and, to a lesser extent, by very low-density lipoprotein. The serum concentration of carotenoids after a single dose peaks at 24 to 48 hours post dose. The average lutein concentration in human serum is 280 nM
(2). Lutein is primarily stored in adipose and the liver. Of all the carotenoids circulating in the body, only two polar species, lutein and zeaxanthin, are contained in the macula
(8).
Metabolism/Excretion:It is assumed that lutein is excreted through the bile and kidneys
(1).
Adverse Reactions
No adverse effects have been reported at normal doses.
(1)Toxicity: Carotenodermia is a harmless biological effect of high carotenoid intake. Characterized by a yellowish discoloration of the skin, it results from chronically elevated serum concentrations of carotenes.
Herb-Drug Interactions
No known drug interactions at this time.
(4)
Literature Summary and Critique
References
- Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. Washington (DC): National Academy Press; 2000.
- Khachik F, Beecher GR, Smith JC. Lutein, lycopene, and their oxidative metabolites in chemoprevention of cancer. J Cell Biochem Suppl 1995;22:236-46.
- van het Hof KH, et al. Bioavailability of lutein from vegetables is 5 times higher than that of beta-carotene. Am J Clin Nutr 1999;70:261-8.
- Elinder LS, et al. Probucol treatment decreases serum concentrations of diet-derived antioxidants. Arterioscler Thromb Vasc Biol 1995;15:1057-63.
- Sujak A, Okulski W, Gruszecki WI. Organisation of xanthophyll pigments lutein and zeaxanthin in lipid membranes formed with dipalmitoylphosphatiylcholine. Biochim Biophys Acta 2000;1509:255-63.
- Dwyer JH, et al. Oxygenated carotenoid lutein and progression of early atherosclerosis: the Los Angeles atherosclerosis study. Circulation 2001;103:2922-7.
- Slattery ML, et al. Carotenoids and colon cancer. Am J Clin Nutr 2000;71:575-82.
- Olmedilla B, et al. A European multicentre, placebo-controlled supplementation study with alpha-tocopherol, carotene-rich palm oil, lutein or lycopene; analysis of serum responses. Clin Sci (Lond) 2002;102:447-56.
- Dagnelie G, Zorge IS, McDonald TM. Lutein improves visual function in some patients with retinal degeneration: a pilot study via the internet. Optometry 2000;71:147-64.
- Chong EW, Wong TY, Kreis AJ, et al. Dietary antioxidants and primary prevention of age related macular degeneration: systematic review and meta-analysis. BMJ 2007;335(7623):755.
- Satia JA, Littman A, Slatore CG, et al. Long-term use of beta-carotene, retinol, lycopene, and lutein supplements and lung cancer risk: results from the VITamins And Lifestyle (VITAL) study. Am J Epidemiol. 2009 Apr 1;169(7):815-28. Erratum in: Am J Epidemiol. 2009 Jun 1;169(11):1409. Dosage error in article text.
