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The Antioxidant Lycopene and Its Role in the Prevention of Risk for Osteoporosis in Postmenopausal Women
Lycopene is a potent antioxidant
Lycopene is a 40-carbon, acyclic isomer of β-carotene1. Among the carotenoid family, it is credited with the highest singlet oxygen quenching capacity2, which makes it a powerful antioxidant. Lycopene is the most predominant carotenoid found in human serum1. Over 80% of lycopene consumed in the diet is obtained through consumption of tomatoes and tomato products3. However, it is also found in watermelon, pink grapefruit, rosehips and pink guava4.
Lycopene is well documented for its ability to decrease biomarkers of oxidative stress. Research shows that it is capable of decreasing lipid, protein and DNA markers. The antioxidant properties of lycopene have been credited with its ability to decrease the risk of age-related chronic diseases often attributed to oxidative stress. Research suggests that through its antioxidant capacity, lycopene may decrease the risk of infertility, diabetes, dementia, cardiovascular disease and several types of cancer5. Our research suggests that lycopene may also act in its antioxidant capacity to decrease the risk of osteoporosis in postmenopausal women.
Intake of dietary lycopene is important to improve antioxidant status
In a cross-sectional study we have shown that those with a high daily intake of lycopene consumed on average, more cooked and processed tomato products, which usually contain higher amounts of lycopene. In order to increase serum concentrations of the antioxidant-rich 5-cis lycopene, an increased consumption of foods rich in bioavailable lycopene, such as processed tomato products, should be considered6.
We have recently reported data showing that lycopene restriction, for a period of only one month, resulted in important changes in biomarkers of oxidative stress and bone resorption markers in postmenopausal women aged 50-607. Refraining from consuming lycopene-containing foods resulted in significantly lower serum lycopene, which coincided with increases in oxidative stress parameters and the bone resorption marker NTx. This significant increase in NTx may lead to a long-term decrease in BMD and increased risk for osteoporotic fracture8, suggesting that a longer restriction period may be detrimental to bone health7.
Lycopene supplementation may decrease the risk of osteoporosis in postmenopausal women
Further support to the importance of lycopene in the daily diet is given by our randomized controlled trial in which supplementation with lycopene resulted in significant increased in total antioxidant capacity which corresponded to significantly lower oxidative stress parameters and the bone resorption marker N-telopeptide of Type I collage (NTx). These findings show capsule or juice forms of lycopene, supplying at least 30 mg of lycopene day, may decrease the risk of osteoporosis by decreasing oxidative stress parameters and the bone resorption marker NTx. Based on these findings, the consumption of lycopene by women to improve overall bone health should be considered as a natural complementary or alternative supplement for the prevention and treatment of osteoporosis in postmenopausal women9.
Lycopene is present in only select number of foods4; therefore targeted consumption of these products as a part of the regular daily diet to decrease negative health consequences in women, particularly with respect to osteoporosis risk, should be considered. Presently, lycopene is not considered to be an essential nutrient with no formal daily intake levels specified, however, based on human intervention studies an intake of 8-10 mg per day is recommended. Results from our research also provide further proof of the importance of consuming tomatoes and tomato products as a source of lycopene in the daily diet in maintaining overall health and decreasing the risk for age-related chronic diseases, particularly osteoporosis, which is associated with oxidative stress.
- Rao, A. V. & Agarwal, S. Role of antioxidant lycopene in cancer and heart disease. J Am Coll Nutr 19(5): 563-9 (2000).
- Di Mascio, P., Kaiser, S. & Sies, H. Lycopene as the most efficient biological carotenoid singlet oxygen quencher. Arch Biochem Biophys 274(2): 532-8 (1989).
- Boileau, T. W., Boileau, A. C. & Erdman, J. W., Jr. Bioavailability of all-trans and cis-isomers of lycopene. Exp Biol Med (Maywood) 227(10): 914-9 (2002).
- U.S. Department of Agriculture, A. R. S. (United States Department of Agriculture, 2009).
- Rao, A. V. & Rao, L. G. Carotenoids and human health. Pharmacol Res 55(3): 207-16 (2007).
- Mackinnon ES, Rao AV, Rao LG. Lycopene intake by Canadian women is variable, similar among different ages, but greater than that reported for women in other countries. J Med Food. 2009 Aug;12(4):829-35.
- Mackinnon ES, Rao AV, Rao LG. Dietary restriction of lycopene for a period of one month resulted in significantly increased biomarkers of oxidative stress and bone resorption in postmenopausal women. J Nutr Health Aging. 2011 Feb;15(2):133-8.
- Brown, J. P. & Josse, R. G. 2002 clinical practice guidelines for the diagnosis and management of osteoporosis in Canada. CMAJ 167S1-S34 (2002).
- Mackinnon ES, Rao AV, Josse RG, Rao LG. Supplementation with the antioxidant lycopene significantly decreases oxidative stress parame ters and the bone resorption marker N-telopeptide of type I collagen in postmenopausal women. Osteoporos Int. 2011 Apr;22(4):1091-101.