Lycopene health effects

A concern has been raised that phytosterol doses that are effective for cholesterol reduction may impair the absorption and lower blood concentrations of fat-soluble vitamins and antioxidants. A number of studies showed that phytosterols had no effect on plasma concentrations of vitamin D, retinol, or plasma-lipid-standardized alpha-tocopherol. Moreover, the reports of the effect of phytosterols on concentrations of blood carotenoids (lutein, lycopene, and alpha-carotene) are controversial. There seems to be general agreement that phytosterol doses >1 g/d significantly decrease LDL-C standardized beta-carotene concentrations however, it remains to be determined whether a reported 15-20% reduction in beta-carotene due to phytosterol supplementation is associated with adverse health effects. Noakes et al. found that consumption of one or more carotenoid-rich vegetable or fruit servings a day was sufficient to prevent lowering of plasma carotenoid concentrations in 46 subjects with hypercholesterolemia treated with 2.3 g of either sterol or stanol esters. 

Data concerning gastric cancer are scarce. The prospective Netherlands Cohort Study found no correlation between lutein dietary intake and gastric cancer risk, whereas findings from the Physicians Health Study and the ATBC study reported no effect of P-carotene on gastric cancer incidence. Two case-control studies and three intervention trials (ATBC, CARET, and the Physicians Health Study ) showed no association of P-carotene, lycopene, lutein, zeaxanthin, and P-cryptoxanthin. 

However, intervention trials investigating the effects of P-carotene and lycopene supplementation on CVD have not reported convincing results (Table 3.1.3). Among the seven studies reviewed herein, four primary prevention trials, namely the Multicenter Skin Cancer Prevention Study, the Beta Carotene and Retinol Efficacy Trial, the ATBC cancer prevention study, " and the Physicians Health Study have shown no association between a supplementation of P-carotene and risk of death from CVD or fatal and non-fatal MI. 

Epidemiological data on carotenoids and cerebral infarcts or strokes indicate a protective effect of P-carotene and lycopene. Indeed, the Basel prospective study, the Kuopio Ischaemic Heart Disease Risk Factor study, and the Physicians Health Study " have shown an inverse correlation between carotenoid plasma level and risk of stroke. In the same way, Hirvonen et al. demonstrated, in findings from the ATBC cancer prevention stndy, an inverse association between P-carotene dietary intake and stroke. However, clinical data on carotenoids and stroke are nonexistent and they are needed to confirm this possible protective effect of carotenoids on stroke. 

The second major difficulty is that cells and tissues in the body are exposed to numerous metabolites displaying different structures compared to the parent molecules present in plant foods. For example, it has been suggested that the metabolites of lycopene may be responsible for reducing the risk of developing prostate cancer. These metabolites may interact with nuclear receptors such as PPARs, LXR, and others. " Future research is needed to produce metabolites (enzymatically or chemically) in order to elucidate their cellular mechanisms and thus clarify their effects on human health. 

Kim, H.S. and Lee, B.M., Protective effects of antioxidant supplementation on plasma lipid peroxidation in smokers, J. Toxicol. Environ. Health A, 63, 583, 2001. Gaziano, J.M. et al.. Supplementation with beta-carotene in vivo and in vitro does not inhibit low density lipoprotein oxidation. Atherosclerosis, 112, 187, 1995. Sutherland, W.H.F. et al.. Supplementation with tomato juice increases plasma lycopene but does not alter susceptibility to oxidation of low-density lipoproteins from renal transplant recipients, Clin. Nephrol, 52, 30, 1999. 

Lower doses (at or below 200 Gy) of irradiation coupled with 35 days of storage at 10°C were not harmful in the retention of lycopene and other health-promoting compounds in early-season grapefruit, but higher doses (400 and 700 Gy) and 35 days of storage had detrimental effects. However, no significant effect of radiation and storage was observed in late-season fruit (Patil and others 2004). 

The role of lycopene in bone health to date is based on its potent antioxidant properties, the well-known role of oxidative stress in bone health, and the limited reported studies on the effects of lycopene in bone cells in culture. Therefore, in order to understand the role that lycopene can play in bone health, we have included a review of the reported studies on the role of oxidative stress in bone health and bone cells. 

This chapter provides an overview of lycopene bioavailability and the potential benefits of dietary lycopene on human health. Lycopene chemistry and its effect on functionality will be discussed, followed by the effects of processing on lycopene obtained from tomatoes. Finally, methods of analysis and of extraction from tomatoes are discussed. 

The present volume also addresses the issue of processing and its effects on the bioavailability of bioactives. It shows that processing of a functional food may have profound effects on specific health benefits it claims to deliver. As illustrated in Chapter 4, the physiological effects of lycopene are altered significantly during processing, primarily due to its isomerization and oxidation. Worth noting, however,... 

The potential beneficial effects of lycopene in human health have been reviewed extensively in recent years [39-45] numerous observational studies have consistently shown an inverse relationship between the consumption of lycopene-rich diets (tomato or tomato-based foods) or plasma lycopene levels with the risk of cancers at various sites [46, 47]. The strongest inverse relationship was that for prostate cancer [2, 46-49], one of the most prevalent male cancers in the western populations and common across the world other significant inverse relationships were found with lung and stomach cancers. 

The ability of lycopene to act as an antioxidant and scavenger of free radicals is frequently cited as the most likely mechanism that could account for the hypothesized beneficial effects on human health.Supporting this theory, protection against oxidative stress has been shown in parallel with a preferential destraction of lycopene relative to P-carotene in a study of human skin irradiated with ultraviolet (UV) light. Further, the ability of carotenoids to act as antioxidants has been hypothesized as the mechanism underlying the protection of the human retina from photooxidation, a process that over time can result in the pathologies of age-related macular degeneration (AMD) and cataracts. ... 

Figure 111.1 shows the principal carotenoids found in natural products, together with zeaxanthin, which is not as ubiquitous. p-Carotene, a-carotene, p-cryptoxanthin, lutein, and lycopene are also the carotenoids most conunonly found in human plasma. These carotenoids, together with zeaxanthin, have been shown to have health-promoting effects. 

In this chapter, we have summarized the potential effects of lycopene in prevention and treatment of cancer. Lycopene intake and plasma levels of lycopene have been inversely associated with cancer risk in most of the case-control studies and animal studies. Clinical trials need to be craiducted to investigate lycopene in prevention of cancer and as an adjunct to standard cancer therapy. Until more data is available regarding lycopene supplementation, it is suggested that the potential health benefits of lycopene can best be achieved through a diet rich in a variety of fruits and vegetables, which include tomatoes. 

Al-Malki AL, Moselhy SS, Refai MY (2012) Synergistic effect of lycopene and tocopherol against oxidative stress and mammary tumorigenesis induced by 7,12-dimethyl[a] benzanthracene in female rats. Toxicol Ind Health 28 542-548... 

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