Carotenoid dietary

Botterweck, A. A. et al., Vitamins, carotenoids, dietary fiber, and the risk of gastric carcinoma results from a prospective study after 6.3 years of foUow-up, Cancer, 88, 131, 2000. 

Plants are the major source for dietary provitamin A. As mammals and humans cannot synthesize carotenoids, dietary provitamin A is obtained from plant sources that contain carotenoids having 2,6,6-trimethyl-l-cyclohexen-l-yl rings, such as P-carotene. More than 600 carotenoids have been identified in plants and algae, which together biosynthesize about 0.1 billion tons of carotenoids each year. However, only about ten carotenoids, including P-carotene, are nutritionally significant members of the provitamin A class that can be oxidatively metabolized to retinal in mammals and humans by such organs as the intestine, liver, and kidney and then reduced to retinol. 

One practical outcome of research on a fruit is its widespread application as a food for alleviating diseases associated with malnutrition. Particularly in impoverished western Africa, mango is a practical food source of nutrients, especially provitamin A carotenoids, dietary fiber,... 

Carotenoids are also used as pigments and dietary supplements in animals and poultry feedstuffs. They are added to pharmaceutical products to provide a form of control during manufacturing and to distinguish one product from another. They also enhance the aesthetic aspects of the products (210). 

Rich sources of vitamin A include dairy products such as milk cheese, butter, and ice cream. Eggs as well as internal organs such as the Hver, kidney, and heart also represent good sources. In addition, fish such as herring, sardines, and tuna, and in particular the Hver oil from certain marine organisms, are excellent sources. Because the vitamin A in these food products is derived from dietary carotenoids, vitamin A content can vary considerably. Variation of vitamin A content in food can also result from food processing and in particular, oxidation processes (8). 

Several studies have investigated the role of dietary factors in prostate cancer risk, but results appear inconsistent. Significant effects have not been detected for dietary soya products certain vegetables, beans, fruit, rice and seaweed appear to be protective in some studies, while another has shown no protective effect from seaweed or vegetable consumption. In addition, a number of other risk factors have been shown to be associated with an increased risk of this cancer, including meat and dairy products and carotenoids. 

Saffron is a spice that is used sometimes for flavor, but mostly for the yellow color it imparts to foods. Because of its expense, saffron is often replaced in recipes by another carotenoid, annatto, or the unrelated dye molecule in turmeric. Like the other carotenoid dyes, saffron is an antioxidant, but its expense makes it unsuitable as a preservative or dietary supplement. 

The antioxidant activities of carotenoids and other phytochemicals in the human body can be measured, or at least estimated, by a variety of techniques, in vitro, in vivo or ex vivo (Krinsky, 2001). Many studies describe the use of ex vivo methods to measure the oxidisability of low-density lipoprotein (LDL) particles after dietary intervention with carotene-rich foods. However, the difficulty with this approach is that complex plant foods usually also contain other carotenoids, ascorbate, flavonoids, and other compounds that have antioxidant activity, and it is difficult to attribute the results to any particular class of compounds. One study, in which subjects were given additional fruits and vegetables, demonstrated an increase in the resistance of LDL to oxidation (Hininger et al., 1997), but two other showed no effect (Chopra et al, 1996 van het Hof et al., 1999). These differing outcomes may have been due to systematic differences in the experimental protocols or in the populations studied (Krinsky, 2001), but the results do indicate the complexity of the problem, and the hazards of generalising too readily about the putative benefits of dietary antioxidants. 

HUGHES D A (2001) Dietary carotenoids and human immune function , Nutrition, 17, 823-7. 

Table 7.1 Common dietary sources of carotenoids in regular vegetable foods, xg/100 fresh weight. Data are means derived from literature sources. The normal range of values is the mean at least 85%, and depends upon variety, agronomic conditions, tissue sampled and maturity... 

Table 7.1 shows the common dietary sources of carotenoids in regular vegetable foods, p,g/100 fresh weight. Although the greatest amount of the hydrocarbon carotenoids is present as the all-trans isomer, there is always a proportion of cis isomers present. This table represents only a small number of the fruits and vegetables that contribute carotenoids in the European diet. For more comprehensive information readers are directed to A European Carotenoid Database O Neill et al, 2001, which lists the carotenoid composition of over 100 food items. 

The relationship between serum and tissue concentrations of lutein and zeaxanthin was recently studied by Johnson et al, (2000). Dietary intake of xanthophyll-rich vegetables (for example, spinach and com) resulted in significant increases in lutein concentration in serum, adipose tissue and buccal cells, and this correlated with changes in MP density. However, P-carotene and lycopene are normally the major carotenoids detected in buccal cells (Peng et al, 1994). 

COOPER D A, ELDRiDGE A L and PETERS J c (1999) Dietary carotenoids and certain cancers, heart disease and age-related macular degeneration a review of recent research , iVMtr Rev, 57, 201-14. 

MORTENSEN A, SKIBSTED L H and TRUscoTT T G (2001) The interaction of dietary carotenoids with radical species , Arch Biochem Biophys, 385, 13-19. 

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. ... 

In animals, the major function of carotenoids is as a precursor to the formation of vitamin A. Carotenoids with provitamin A activity are essential components of the human diet, and there is considerable evidence that they are absorbed through the diet and often metabohzed into other compounds. Beyond their important role as a source of vitamin A for humans, dietary carotenoids, including those that are not provitamin A carotenoids, have been implicated as protecting against certain forms of cancer and cardiovascular disease. ... 

Osganian, S.K. et al.. Dietary carotenoids and risk of coronary artery disease in women. Am J Clin Nutr., 77, 1390, 2003. 

Daily consumption of various fruits, vegetables, and derived juices contributes to human intake of carotenoids. The estimation of carotenoid intakes has been made possible throngh publication of the qnalitative and qnantitative carotenoid contents of commonly consnmed foods. Average intake estimates in the United States are around 6.5 mg/day. In seven conntries in Enrope, the average total carotenoid intake based on the snm of the five carotenoids was approximately 14 mg/day. When dietary source of carotenoids were analyzed, carrots appeared as the major sonrces of p-carotene in all conntries except Spain, where spinach was the main contribntor. 

Carotenoids and prostate cancer — Numerous epidemiological studies including prospective cohort and case-control studies have demonstrated the protective roles of lycopene, tomatoes, and tomato-derived products on prostate cancer risk other carotenoids showed no effects. " In two studies based on correlations between plasma levels or dietary intake of various carotenoids and prostate cancer risk, lycopene appeared inversely associated with prostate cancer but no association was reported for a-carotene, P-carotene, lutein, zeaxanthin, or p-cryptoxanthin. - Nevertheless, a protective role of all these carotenoids (provided by tomatoes, pumpkin, spinach, watermelon, and citrus fruits) against prostate cancer was recently reported by Jian et al. ... 

Carotenoids and breast cancer — Among seven case-control studies investigating the correlation between different carotenoid plasma levels or dietary intakes and breast cancer risk, five showed significant inverse associations with some carotenoids. - In most cases, this protective effect was due to 3-carotene and lutein. However, one (the Canadian National Breast Screening Study ) showed no association for all studied carotenoids including (I-carotene and lutein. More recently, another study even demonstrated a positive correlation between breast cancer risk and tissue and serum levels of P-carotenes and total carotenes. Nevertheless, these observational results must be confirmed by intervention studies to prove consistent. 

Carotenoids and urino-digestive cancers — On the whole, findings from epidemiological studies did not demonstrate a protective role of carotenoids against colorectal, gastric, and bladder cancers. Indeed, most prospective and case-control studies of colorectal cancer showed no association with dietary intake or plasma level of most carotenoids. - Only lycopene and lutein were shown to be protective against colorectal cancer. Otherwise, findings from the ATBC study s showed no effect of P-carotene supplementation on colorectal cancer. 

Among 27 prospective and case-control studies, 16 reported inverse associations between some carotenoids and CVDs, taking plasma or serum concentration as carotenoid biomarkers (11 of 16 studies), dietary intake (5 of 16 studies), or adipose tissue level (1 of 16 studies). With regard to the findings from the studies based on CVD risk, only two of seven presented significant inverse associations of carotenoids, particularly lycopene and P-carotene, whereas five studies of nine showed inverse correlations between myocardial infarcts and lycopene and/or P-carotene the others presented no associations. ... 

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. 

Jian, L. et al.. Do dietary lycopene and other carotenoids protect against prostate cancer Int. J. Cancer, 113, 1010, 2005. 

Potischman, N. et al.. Breast cancer and dietary and plasma concentrations of carotenoids and vitamin A, Am. J. Clin. Nutr, 52, 909, 1990. 

Holick, C.N. et al., Dietary carotenoids, serum beta-carotene, and retinol and risk of lung cancer in the alpha-tocopherol, beta-carotene cohort study, Am. J. Epidemiol., 156, 536, 2002. 

Nkondjock, A. and Ghadirian, P, Dietary carotenoids and risk of colon cancer case-control study, Int. J. Cancer, 110, 110, 2004. 

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