Lycopene bioavailability

Rao AV and Shen FI. 2002. Effect of low dose lycopene intake on lycopene bioavailability and oxidative... 

AMS has been used for many years to study the pharmacokinetics of (3-carotene, as has been reviewed by van Lieshout et al. (2003). Recent studies have been performed on the absorption of (3-carotene and metabolism to vitamin A (Dueker et ah, 2000 Hickenbottom et ah, 2002a) and other metabolites (Ho et ah, 2007) in humans. AMS has also been used to monitor the kinetics of lutein metabolism (Moura et ah, 2005) and lycopene bioavailability and metabolism (Ross et ah, 2011) in humans. 

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 composition and structure of food have an important bearing on lycopene bioavailability. Food characteristics may affect the release of lycopene from the tomato tissue matrix. Practices such as cooking or fine grinding can increase bioavailability by physically disrupting or softening plant cell walls and by disrupting lycopene-protein complexes (Hussein and El-Tohamy, 1990). 

Lycopene bioavailability is influenced by many factors. Since the bioavailability of lycopene cis isomers is higher than that of trans isomers, it follows that lycopene bioavailability from processed tomato products is higher than that from unprocessed fresh tomatoes. Further, the total lycopene content of processed foods is higher than that of... 

Sies, H. and Stahl, W., Lycopene antioxidant and biological effects and its bioavail-abihty in the human, Proc. Soc. Exp. Biol. Med., 218, 121, 1998. 

Rao, A.V. and Agarwal, S., Bioavailability and in vivo antioxidant properties of lycopene from tomato products and their possible role in the prevention of cancer, Nutr. Cancer, 3, 199, 1998. 

Reboul, E. et al.. Enrichment of tomato paste with 6% tomato peel increases lycopene and 3-carotene bioavailability in men, J. Nutr, 135, 790, 2005. 

Boileau, A. C., N. R. Merchen, K. Wasson, C. A. Atkinson, and J. W. Erdman, Jr. 1999. Cis-lycopene is more bioavailable than trans-lycopene in vitro and in vivo in lymph-cannulated ferrets. J Nutr 129(6) 1176—1181. 

Unlu, NZ, T Bohn, DM Francis, HN Nagaraja, SK Clinton, and SJ Schwartz. 2007. Lycopene from heat-treated cA-isomer-rich tomato sauce is more bioavailable than from all-/ram-rich tomato sauce in human subjects. BrJ Nutr 98(1) 140-146. 

Horvitz MA, Simon PW and Tanumihardjo SA. 2004. Lycopene and beta-carotene are bioavailable from lycopene red carrots in humans. Eur J Clin Nutr 58 803-811. 

Source Lycopene content of tomato products Its stability, bioavailability and in vivo antioxidant properties. Reprinted from Journal of Medicinal Food. 2001 4, pp. 9-15 by permission of Mary Ann Liebert, Inc., Publishers. 

VI. BIOAVAILABILITY, TISSUE DISTRIBUTION, METABOLISM, AND SAFETY OF LYCOPENE... 

Handelman et al., 1996). Alcohol consumption was also shown to alter serum lycopene levels (Brady et al., 1997). Other factors that influence the bioavailability of lycopene are its release from the food matrix due to processing, presence of dietary lipids, and heat-induced isomerization from the all-trans to cis conformation. They all enhance lycopene absorption into the body. Ingestion of cooked tomato juice in oil medium increased serum lycopene levels threefold whereas consumption of an equal amount of unprocessed juice did not have any effect (Stahl and Sies, 1992). 

Lycopene and its oxidation products are present in human milk and other body fluids (Khachik et al., 1997). Human seminal plasma also contains lycopene and its levels were lower in immunoinfertile men compared to normal individuals (Palan and Naz, 1996). Although the plasma or serum levels of lycopene are used commonly to assess its bioavailability, adipose tissue has been suggested as a better tissue for the assessment of body lycopene status (Kohlmeier et al., 1997). 

Gartner, C., Stahl, W., and Sies, H. 1997. Lycopene is more bioavailable from tomato paste than from fresh tomatoes. Am. J. Clin. Nutr. 66, 116-122. 

Jain, C.K., Agarwal, S., and Rao, A.V. 1999. The effect of dietary lycopene on bioavailability, tissue distribution, in-vivo antioxidant properties and colonic preneoplasia in rats. Nutr. Res. 19, 1383-1391. 

When considering the addition of a bioactive to food, it is useful to classify them as oil-soluble (e.g., polyunsaturated fatty acids, carotenes, lycopene), water-soluble (e.g., anthocyanins, proteins and peptides), or water/oil dispersible components (e.g., probiotics). Bioactives may be added directly to food if they are in a compatible format with the food matrix and provided their direct addition does not impact negatively on food quality or the bioavailability of the bioactive. When the solubility in a food matrix is limiting, its hydrophilicity/lipophilicity may be modified to enable improved incorporation. An example is the conversion of free plant sterols to fatty acid esters in order to make them more oil-soluble and readily incorporated into spreads (Deckere de and Verschuren 2000). 

No carotenoids were detected in tissues of animals sacrificed after 6 weeks. However, as shown in Table 10.4, after 24 weeks, nearly all carotenoids (lutein, zeaxanthin, lycopene, y-carotene, -carotene, a-carotene, P-carotene, phytofluene, phytoene) were bioavailable in colon and liver of the animals that received MCM. A typical HPLC profile of carotenoids in a pooled extract from mouse liver is shown in Figure 10.2. The major carotenoids in brain were lycopene, lutein, and P-carotene. Carotene predominated in the breast tissues, while lutein, lycopene, y-carotene, and a-carotene were detected in low concentrations. Carotenoids were not detected in tissues of the mice on WD without MCM. 

Khachik, R, Steck, A., and Pfander, H., Bioavailability, metabolism, and possible mechanism of chemoprevention by lutein and lycopene in humans, in Food Factors for Cancer Prevention, Ohigashi, H., Osawa, T., Terao, J., Watanabe, S., Yoshikawa, T., Eds., Springer-Verlag, Tokyo, 1997, p. 542. 

Lycopene is the major carotenoid pigment found in tomatoes, along with lesser amounts of a-, P-, y-, and -carotene, phytoene, phytofluene, neurosporene, and lutein (Trombly and Porter, 1953 Kargl et al., 1960). The basic physicochemical information on lycopene is fairly well established and is outlined in Table 4.1. Lycopene is dispersible in edible oils and soluble in apolar organic solvents. In aqueous systems, lycopene tends to aggregate and to precipitate as crystals this behavior is suspected to inhibit the bioavailability of lycopene in humans (Zumbrunn et al., 1985). In fresh tomatoes, the crystalline form of lycopene is responsible for the typical bright red of the ripe fruits. 

The structures of some prominent d,v-isomcrs of lycopene are shown in Figure 4.2. G. s-isomers have distinct physicochemical characteristics (and hence, bioactivity and bioavailability) compared to their all-trans counterparts. In general, the di-isomers are more soluble in oil and hydrocarbon solvents than their all-trans counterparts. They are less prone to crystallization because of their kinked structures. They also are less intense in color, which may influence the consumers perception of food quality. The appearance of a distinct absorption maximum in the UV region ( di-peak ) is useful for distinguishing between the different isomers. 

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