The Health Benefits of Lycopene

Lycopene is the pigment responsible for the characteristic red color of ripe tomatoes, pink grapefruit, guava, and watermelon. There is increasing clinical evidence supporting the role of lycopene—an important carotenoid—as an antioxidant. Carotenoids are a class of hydrocarbons (carotenes) and their oxygenated derivatives (xanthophylls). They are composed of eight isoprenoid units arranged in such a manner that these units reverse at the center of the molecule with the two central methyl groups being in the 1,6-position relationship and the remaining non-terminal methyl groups in the 1,5-position. Approximately 600 carotenoids have been isolated from natural sources and are all derived from the acyclic C40H56 structure. In most cases, each carotenoid occurs solely in one configuration in Nature. The most notable of the carotenoids are lycopene and beta-carotene.

An interesting feature of carotenoid stereochemistry is that carotenes exist in two isomeric forms, cis and trans. Both forms exist in nature and exhibit different biological properties. Based on the number of double bonds in the molecule, a great number of cis/trans isomers exist for each carotenoid: 1,056 for lycopene and 272 for beta-carotene. Normally, carotenoids occur naturally as the all trans isomer, but exposure to heat and ultraviolet (UV) light can increase the percentage of the cis isomer.

Tomatoes and tomato-based products are the major source of lycopene and other carotenoids in the human diet. Fresh tomatoes, soup, and most processed tomato-based products have predominantly the trans-lycopene isomer and a small amount of the cis-lycopene. In biological tissues, about 60-65 percent of lycopene is in the cis isomeric form. A study of the bioavailability of the two different isomeric forms of lycopene was conducted by feeding test subjects specially bred tomatoes that were either poly-cis or all all-trans. Lycopene from the poly-cis tomato was better absorbed than the all-trans tomato. Conversion of the trans to the cis isomer occurred after absorption. What is fed is what is absorbed, demonstrating that the conversion does not take place at the gut level. It is not clear if the conversion takes place in the tissues or in the liver. It is likely not due to an enzyme but a simple isomerization of the lycopene in the body. This seems to be supported by the fact that lycopene is stable in the tomato and once removed becomes susceptible to reactions. Based on studies, it appears that co-consumption of fat is essential for the absorption of carotenoids. The reason and significance for the isomeric trans-cis change in form is unknown.

Effect at the tissue level

Joseph Levy, Ph.D., at Ben-Gurion University of the Negev in Beer-Sheva, Israel, has shown that lycopene inhibits estradiol stimulation of hormone-dependent malignant cells. Estrogen, androgen, and IGF-1 regulate cell division. Antiestrogens and lycopene inhibit a key protein in cell cycle regulation known as Cyclin D that is over-expressed in cancer cells. Some carotenoids inhibit estradiol-induced estrogenic receptor activity in cancer cells. This has implications for women with breast and endometrial tumors and men with prostate cancer.

Reactive oxygen species (ROS) affects bone cells by decreasing osteoblast (bone forming) function and increases osteoclast (bone resorbing) activity. Leticia Rao, Ph.D., at St. Michael’s Hospital at the University of Toronto hypothesizes that lycopene inhibits ROS. Lycopene treated osteoclasts do not fuse to grow larger when treated with lycopene, while osteoblastic proliferation is stimulated by lycopene. The role of lycopene in the prevention and treatment of osteoporosis is currently under investigation.

High levels of ROS are found in 25-40 percent of infertile men and may be of clinical significance in idiopathic oligoasthenospermia (severely depressed sperm count). Lycopene is being studied to see if it can reduce oxidative stress and improve sperm count.

Photooxidative stress from UV light affects the eyes and the skin. It results in the formation of ROS and peroxyl radicals that damage proteins, lipids, and DNA and may be responsible for skin aging, photosensitivity disorders, and skin cancer. Chiang et al at Fu Jen Catholic University in Taiwan showed that platelet-derived growth factor-BB (PDGF-BB) was inhibited by lycopene (Life Sci. 2007;81:1509-1517). Trapping of PDGF-BB by lycopene compromised melanoma-induced fibroblast migration and attenuated signaling transduction in fibroblasts simulated by melanoma-derived conditioned medium, suggesting that lycopene may interfere with tumor-stroma interactions. Darvin et al of the Charité-Universitätsmedizin Berlin in Germany found that higher levels of lycopene in the skin effectively lead to lower levels of skin roughness (Eur J Pharm Biopharm. 2008;69:943-947). Likewise, Heinrich’s group at the Institute of Experimental Dermatology in Witten, Germany found the skin of patients treated with lycopene showed improvement in roughness and scaling as determined by Visioscan.

Topical vs. Dietary Lycopene for Skin

Recent studies have suggested that topically applied lycopene may be more effective in protecting the skin than dietary lycopene. Dietary lycopene, once absorbed, distributes throughout the body and deposits in various tissues. Lycopene applied directly to the skin may achieve higher levels and offer a greater degree of protection from UV-induced oxidative stress. Fazekas et al of Mount Sinai School of Medicine in New York found that topically applied lycopene prevented the cleavage of caspase-3 and significantly reversed UVB-induced proliferating cell nuclear antigen (PCNA) and normal PCNA staining (Nutr Cancer. 2003;47:181-187) Furthermore, topically applied lycopene may act as a preventive agent via inhibition of epidermal ornithine decarboxylase activity, reducing inflammatory responses, maintaining normal cell proliferation, and possibly preventing DNA damage. Andreassi et al of the Istituto Tecnologica di Scienza Dermatologiche at Università degli Studi di Siena, Siena, Italy, similarly found topical lycopene to have suitable characteristics to be used successfully in the prevention of cutaneous damage by free radicals (J Eur Acad Dermatol Venereol. 2004;18:52-55).

For lycopene to be used in a cutaneous preparation, certain parameters must be met. Contrary to many blogs on the internet, it is not true that adding powdered lycopene to any face cream is sufficient to create a lycopene cream. As has been elucidated above, once lycopene undergoes reduction by singlet oxygen radicals it becomes inactive. Other factors such as exposure to UV light and reducing agents in the creams themselves degrade and inactivate lycopene. To protect lycopene, it needs to be encapsulated. Two methods are available to do this: a liposome envelope or newer and more efficiently absorbed cerosome envelope. Both of these methods also protect the skin from the orange staining that can sometimes be associated with topically applied lycopene.

Another important consideration in choosing a face cream containing lycopene is whether the lycopene is natural or synthetic. Aust et al of the Institute for Biochemistry and Molecular Biology at Heinrich-Heine-University in Dusseldorf, Germany, found that natural lycopene exerted a more protective effect than synthetic lycopene (Int J Vitam Nutr Res. 2005;75:54-60). Other studies show that natural lycopene has almost 50 percent greater ability to kill malignant cells in vitro than synthetic lycopene.

Conclusion

Lycopene is one of the most powerful antioxidants found in nature. Creams containing lycopene offer protection from the damaging effects of environmental contaminants and UV radiation responsible for photoaging and skin cancer. It is important that the cream contain a substantial amount of lycopene, that is natural and not synthetic, and that the lycopene is protected by either a liposomal or cerosomal envelope. Research is ongoing and results are encouraging for the health benefits of lycopene creams.

This post was contributed by Gary I Weinberger, MD FACS. Gary was a clinical professor of medicine at the Buffalo School of Medicine and also the New York University School of Medicine. Gary is now a Medical Skincare Specialist and works with Paphos Skincare in Ft Lauderdale, Florida. Paphos Skincare has introduced an all natural, organic Lycopene Skincream that is imported from Italy.