Lycopene dietary sources

An evaluation of the Health Professionals Follow-Up Study (Giovannucci et al., 1995) has detected a lower prostate cancer risk associated with the greater consumption of tomatoes and related food products. Tomatoes are the primary dietary source of lycopene and lycopene concentrations are highest in testis and adrenal tissue (Clinton, 1998). In paired benign and malignant prostate tissue from 25 American men, 53-74 yrs, undergoing... 

Lycopene is a bright red pigment that colors several ripe fruits, vegetables, and flowers. Tomato and tomato products are the main dietary sources of this carotenoid, although it is also found in watermelons, guavas, pink grapefruits, and in small quantities in at least 40 plants. - The absorption of lycopene in the human gut is increased by heat treatment, probably because the breakdown of the plant cells makes the pigment more accessible. ... 

III. Chemistry and Dietary Sources of Lycopene IY. Analytical Methods of Measuring Lycopene in Food and Other Biological Materials... 

Carotenoids cannot be synthesized by humans therefore they must be obtained from dietary sources. These are primarily highly pigmented red, orange, and yellow fruits and vegetables. The carotenoid lycopene is red however, not all red fruits and vegetables contain lycopene. For example, the red in strawberries, apples, and cherries is a result of their anthocyanin content whereas, tomatoes, watermelon, and pink grapefruit derive their red color from lycopene. The carotenoids... 

In this article, some key aspects of the chemical and physical properties, the dietary sources, biochemical status indices, and biological significance of lycopene will be described. 

Source Lycopene content of tomato products and their contribution to dietary lycopene. Reprinted from Food Research International. 1999 31, pp. 737-741 by permission of Elsevier. 

Although red-colored fruits and vegetables are the most common sources of dietary lycopene, not all red-colored plants contain lycopene. Common food sources of lycopene are the tomatoes, processed tomato products, watermelons, pink guava, pink grapefruits, papaya, and apricots. The lycopene content of these foods are shown in Table I. 

The characteristic deep-red color of ripe tomato fruit and related products is mainly due to lycopene. This color serves as an important indicator of their quality. Tomatoes and tomato foods are an important source of carotenoids for humans and are a major source of lycopene in the Western diet. Other important sources of dietary lycopene include watermelon, guava, rose hip, papaya and pink grapefruit (Gross, 1987,1991 Beerh and Siddappa, 1959 Mangels et al., 1993) (Table 4.3). 

The main dietary carotenoids are lycopene (linear, no substitutions), fl-carotene and a-carotene (ring closure at both ends, no substitutions), P-cryptoxanthin (ring closure at both ends, substitution in the 3 position), lutein (ring closure at both ends, substitutions in the 3 and 3 positions) and canthaxanthin (ring closure at both ends, [O] substitutions in the 4 and 4 positions). In some tissues, particularly flower petals, the hydroxylated carotenoids may also be present as mono- or di-acyl esters, most commonly with C16 fatty acids. Further oxidation of the terminal ring may occur to produce the mono- and di-epoxides. For an exhaustive list of carotenoids, the Key to Carotenoids (Straub 1987) is a recommended reference source. 

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