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.
30 mg daily
Lycopene, an antioxidant found in tomatoes, helps reduce exercise-related asthma attacks.
Lycopene , an antioxidant related to beta-carotene and found in tomatoes, helps reduce the symptoms of asthma caused by exercising. In one double-blind trial,1 over half of people with exercise-induced asthma had significantly fewer asthma symptoms after taking capsules containing 30 mg of lycopene per day for one week compared to when they took a placebo.
Take 6 mg daily from a tomato extract during periods of high sun exposure
Studies have shown lycopene to be helpful in protecting the skin from sunburn.
Antioxidants may protect the skin from sunburn due to free radical–producing ultraviolet rays.2 Combinations of 1,000 to 2,000 IU per day of vitamin E and 2,000 to 3,000 mg per day of vitamin C, but neither given alone, have a significant protective effect against ultraviolet rays, according to double-blind studies.3 , 4 , 5
Oral synthetic beta-carotene alone was not found to provide effective protection when given in amounts of 15 mg per day or for only a few weeks’ time in larger amounts of 60 to 90 mg per day, but it has been effective either in very large (180 mg per day) amounts or in smaller amounts (30 mg per day) in combination with topical sunscreen.6 , 7 , 8 , 9 , 10
Natural sources of beta-carotene or other carotenoids have been more consistently shown to protect against sunburn. One controlled study found that taking a supplement of natural carotenoids (almost all of which was beta-carotene) in daily amounts of 30 mg, 60 mg, and 90 mg gave progressively more protection against ultraviolet rays.11 In another controlled study, either 24 mg per day of natural beta-carotene or 24 mg per day of a carotenoid combination of equal amounts beta-carotene, lutein, and lycopene helped protect skin from ultraviolet rays.12 A preliminary study compared synthetic lycopene (10.1 mg per day), a natural tomato extract containing 9.8 mg of lycopene per day plus additional amounts of other carotenoids, and a solubilized tomato drink (designed to increase lycopene absorption) containing 8.2 mg of lycopene plus additional amounts of other carotenoids. After 12 weeks, only the two tomato-based products were shown to give significant protection against burning by ultraviolet light.13
It should be noted that while oral protection from sunburn has been demonstrated with several types of antioxidants, the degree of protection (typically less than an SPF of 2) is much less than that provided by currently available topical sunscreens. On the other hand, these modest effects will provide some added protection to skin areas where sunscreen is also used and will give a small amount of protection to sun-exposed areas where sunscreen is not applied. However, oral protection from sunburn is not instantaneous; maximum effects are not reached until these antioxidants have been used for about eight to ten weeks.14 , 15
Refer to label instructions
The carotenoid lycopene, present in high amounts in tomatoes, may help prevent atherosclerosis.
The carotenoid, lycopene, has been found to be low in the blood of people with atherosclerosis, particularly if they are smokers.16 Although no association between atherosclerosis and blood level of any other carotenoid (e.g., beta-carotene) was found, the results of this study suggested a protective role for lycopene. Lycopene is present in high amounts in tomatoes.
Refer to label instructions
Large amounts of the carotenoid lycopene have been shown to increase the activity of natural killer cells in the elderly.
Large amounts of the carotenoid lycopene have been shown to increase the activity of NK cells in the elderly. In a controlled trial, 15 mg of lycopene significantly increased NK cell concentration, but no other immune functions.17
4 mg twice per day
In a preliminary trial, supplementing with lycopene reduced the incidence of prostate cancer in men with precancerous changes in their prostate glands.
In a preliminary trial, supplementation with 4 mg of lycopene twice a day for one year reduced the incidence of prostate cancer in men with precancerous changes in their prostate glands.18 Long-term controlled studies are needed to confirm these promising initial reports.
The ideal intake of lycopene is currently unknown; however, the men in the Harvard study with the greatest protection against cancer consumed at least 6.5 mg per day.
Tomatoes and tomato-containing foods are high in lycopene. In the Harvard study, the only tomato-based food that did not correlate with protection was tomato juice. In an unblinded, controlled trial, lycopene supplementation, but not tomato juice, effectively increased the body’s lycopene stores.19 These studies suggest that the lycopene present in tomato juice is poorly absorbed. However, other research indicates that significant amounts of lycopene from tomato juice can, in fact, be absorbed.20 Other foods that contain lycopene include watermelon, pink grapefruit, and guava.
This is unknown, but people who do not eat diets high in tomatoes or tomato products are likely to consume less than optimal amounts.
1. Neuman I, Nahum H, Ben-Amotz A. Reduction of exercise-induced asthma oxidative stress by lycopene, a natural antioxidant. Allergy 2000;55:1184–9.
2. Fuchs J. Potentials and limitations of the natural antioxidants RRR-alpha-tocopherol, L-ascorbic acid and beta-carotene in cutaneous photoprotection. Free Radic Biol Med 1998;25:848–73.
3. Werninghaus K, Meydani M, Bhawan J, et al. Evaluation of the photoprotective effect of oral vitamin E supplementation. Arch Dermatol 1994;130:1257–61.
4. Fuchs J, Kern H. Modulation of UV-light-induced skin inflammation by D-alpha-tocopherol and L-ascorbic acid: a clinical study using solar simulated radiation. Free Radic Biol Med 1998;25:1006–12.
5. Eberlein-Konig B, Placzek M, Przybilla B. Protective effect against sunburn of combined systemic ascorbic acid (vitamin C) and d-alpha-tocopherol (vitamin E). J Am Acad Dermatol 1998;38:45–8.
6. McArdle F, Rhodes LE, Parslew RA, et al. Effects of oral vitamin E and beta-carotene supplementation on ultraviolet radiation-induced oxidative stress in human skin. Am J Clin Nutr 2004;80:1270–5.
7. Garmyn M, Ribaya-Mercado JD, Russel RM, et al. Effect of beta-carotene supplementation on the human sunburn reaction. Exp Dermatol 1995;4:104–11.
8. Wolf C, Steiner A, Honigsmann H, et al. Do oral carotenoids protect human skin against UV erythema, psoralen phototoxicity, and UV-induced DNA damage? J Invest Dermatol 1988;90:55–57.
9. Mathews-Roth MM, Pathak MA, Parrish J, et al. A clinical trial of the effects of oral beta-carotene on the responses of human skin to solar radiation. J Invest Dermatol 1972;59:349–53.
10. Gollnick HP, Hopfenmuller W, Hemmes C, et al. Systemic B-carotene plus topical sunscreen are an optimal protection against harmful effects of natural UV-sunlight. Eur J Dermatol 1996;6:200–5.
11. Lee J, Jiang S, Levine N, Watson RR. Carotenoid supplementation reduces erythema in human skin after simulated solar radiation exposure. Proc Soc Exp Biol Med 2000;223:170–4.
12. Heinrich U, Gartner C, Wiebusch M, et al. Supplementation with beta-carotene or a similar amount of mixed carotenoids protects humans from UV-induced erythema. J Nutr 2003;133:98–101.
13. Aust O, Stahl W, Sies H, et al. Supplementation with tomato-based products increases lycopene, phytofluene, and phytoene levels in human serum and protects against UV-light-induced erythema. Int J Vitam Nutr Res 2005;75:54–60.
14. Sies H, Stahl W. Nutritional protection against skin damage from sunlight. Annu Rev Nutr 2004;24:173–200 [review].
15. Sies H, Stahl W. Carotenoids and UV protection. Photochem Photobiol Sci 2004;3:749-52 [review].
16. Klipstein-Grobusch K, Launer LJ, Geleijnse JM, et al. Serum carotenoids and atherosclerosis. The Rotterdam Study. Atherosclerosis 2000;148:49–56.
17. Corridan BM, O’Donohue MP, Morrissey PA. Carotenoids and immune response in elderly people. Proc Nutr Soc 1998;57:3A–4A.
18. Mohanty NK, Saxena S, Singh UP, et al. Lycopene as a chemopreventive agent in the treatment of high-grade prostate intraepithelial neoplasia. Urol Oncol 2005;23:383–5.
19. Paetau I, Rao D, Wiley ER, et al. Carotenoids in human buccal mucosa cells after 4 wk of supplementation with tomato juice or lycopene supplements. Am J Clin Nutr 1999;70:490–4.
20. Paetau I, Khachik F, Brown ED, et al. Chronic ingestion of lycopene-rich tomato juice or lycopene supplements significantly increases plasma concentrations of lycopene and related tomato carotenoids in humans. Am J Clin Nutr 1998;68:1187–95.
Last Review: 05-01-2013
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