What Are "Star" Ratings?
Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.
For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.
3 Stars Reliable and relatively consistent scientific data showing a substantial health benefit.
2 Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1 Star For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.
This supplement has been used in connection with the following health conditions:
Refer to label instructions
Lutein and zeaxanthin, antioxidants in the carotenoid family, protect the retina from damage caused by sunlight.
Reference Lutein and zeaxanthin are Reference antioxidants in the Reference carotenoid family. These carotenoids, found in high concentrations in spinach, collard greens, and kale, have an affinity for the part of the retina where macular degeneration occurs. Once there, they protect the retina from damage caused by sunlight.1
Harvard researchers reported that people eating the most lutein and zeaxanthin—an average of 5.8 mg per day—had a 57% decreased risk of macular degeneration, compared with people eating the least.2 While spinach and kale eaters have a lower risk of macular degeneration, blood levels of lutein did not correlate with risk of macular degeneration in one trial.3 , 4 In a double-blind study of people with macular degeneration, supplementation with lutein (10 mg per day) for one year significantly improved vision, compared with a placebo.5 Lutein was beneficial for people with both early and advanced stages of the disease. Lutein and zeaxanthin can be taken as supplements; 6 mg per day of lutein may be a useful amount.
How It Works
How to Use It
Whether people who already consume a diet high in fruits and vegetables would benefit further from supplementation with a mixture of carotenoids remains unknown. While smokers clearly should not supplement with isolated synthetic Reference beta-carotene, the effect in smokers of taking either natural beta-carotene or mixed carotenoids is not clear.
Nonetheless, based on health-promoting effects associated with these levels in preliminary research, some doctors recommend that most people supplement with up to 25,000 IU (15 mg) per day of natural beta-carotene and approximately 6 mg each of alpha-carotene, Reference lutein, and Reference lycopene.
Where to Find It
Carotenoids are found in all plant foods. In general, the greater the intensity of color, the higher the level of carotenoids. In green leafy vegetables, Reference beta-carotene is the predominant carotenoid. In the orange colored fruits and vegetables—such as carrots, apricots, mangoes, yams, winter squash—beta-carotene concentrations are high, but other pro-vitamin A carotenoids typically predominate. Yellow vegetables have higher concentrations of yellow carotenoids (xanthophylls), hence a lowered pro-vitamin A activity; but some of these compounds, such as Reference lutein, may have significant health benefits, potentially due to their Reference antioxidant effects. The red and purple vegetables and fruits—such as tomatoes, red cabbage, berries, and plums—contain a large portion of non-vitamin A–active carotenoids. Legumes, grains, and seeds are also significant sources of carotenoids. Carotenoids are also found in various animal foods, such as salmon, egg yolks, shellfish, milk, and poultry. A variety of carotenoids is also found in carrot juice and “green drinks” made from vegetables, dehydrated barley greens, or wheat grass.
Synthetic beta-carotene is available as a supplement. Mixed carotenoids (including the natural form of beta-carotene) are also available in supplements derived from palm oil, algae, and carrot oil.
Carotenoid deficiency is not considered a classic nutritional deficiency like scurvy or beri-beri (severe Reference vitamin C and Reference vitamin B1 deficiencies, respectively). However, given the possible health benefits of carotenoids, most doctors recommend adequate intake. People who do not frequently consume carotenoid-rich foods or take carotenoid supplements are likely to be taking in less than adequate amounts, though optimal levels remain unknown. Also, deficiency may be found in people with chronic Reference diarrhea or other disorders associated with impaired absorption.
Interactions with Supplements, Foods, & Other Compounds
Interactions with Medicines
Certain medicines interact with this supplement.
Replenish Depleted Nutrients
Reduce Side Effects
Potential Negative Interaction
Carotenoids are generally regarded as safe, based primarily on studies with Reference beta-carotene. Increased consumption of carotenoids may cause to the skin to turn orange or yellow—a condition known as “carotenodermia.” This occurrence is completely benign and is unrelated to jaundice—the yellowing of the skin that can result from liver disease or other causes.
Until more is known, people especially smokers should not supplement with synthetic beta-carotene. Two double-blind studies have shown that supplementation with isolated synthetic beta-carotene may increase the risk of Reference lung cancer in people who smoke.7 , 8 Moreover, three of four studies have found small increases in the risk of Reference heart disease in people assigned to take synthetic beta-carotene compared with those assigned to take placebo.9 , 10 , 11 , 12
1. Bone RA. Landrum JT. Distribution of macular pigment components, zeaxanthin and lutein, in human retina. Methods Enzymol 1992:213:360–6.
2. Seddon JM, Ajani UA, Sperduto RD, et al. Dietary carotenoids, vitamins A, C, and E, and advanced age-related macular degeneration. JAMA 1994:272:1413–20.
3. Blumenkranz MS, Russell SR, Robey MG, et al. Risk factors in age-related maculopathy complicated by choroidal neovascularization. Ophthalmology 1986:93:552–8.
4. Mares-Perlman JA, Brady WE, Kleain R, et al. Serum antioxidants and age-related macular degeneration in a population-based case-control study. Arch Ophthalmol 1995;113:1518–23.
5. 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.
6. Probstfield JL, Lin T, Peters J, Hunninghake DB. Carotenoids and vitamin A: The effect of hypocholesterolemic agents on serum levels. Metabolism 1985;34:88–91.
7. Albanes D, Heinone OP, Taylor PR, et al. Alpha-tocopherol and beta-carotene supplements and lung cancer incidence in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study: effects of base-line characteristics and study compliance. J Natl Cancer Inst 1996;88:1560–70.
8. Omenn GS, Goodman GE, Thornquist MD, et al. Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease. N Engl J Med 1996;334:1150–5.
9. Greenburg ER, Baron JA, Karagas MR, et al. Mortality associated with low plasma concentration of beta carotene and the effect of oral supplementation. JAMA 1996;275:699–703.
10. Omenn GS, Goodman GE, Thornquist MD, et al. Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease. N Engl J Med 1996;334:1150–5.
11. The Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group. The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers. N Engl J Med 1994;330:1029–35.
12. Hennekens CH, Buring JE, Manson JE, et al. Lack of effect of long-term supplementation with beta carotene on the incidence of malignant neoplasms and cardiovascular disease. N Engl J Med 1996;334:1145–9.
Last Review: 11-07-2012
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The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2013.