Carotenoid dietary sources

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. 

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. ... 

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. 

Koutsos, E. A., Garcia Lopez, J. C., and Klasing, K. C. 2006. Carotenoids from in ovo or dietary sources blunt systemic indices of the inflammatory response in growing chicks (Gallus gallus domesticus). J. Nutr. 136 1027-1031. 

Animals cannot synthesize carotenoids de novo. To deposit carotenoids in the proper tissues in the proper amounts, they must acquire carotenoids from dietary sources and transport them to target sites. Knowledge of the molecular mechanisms of carotenoid transport, however, is still... 

Vitamin A is an essential nutrient for humans and other vertebrates. Dietary sources of vitamin A are provided either by retinol esters, which are present in foods of animal origin and are hydrolyzed in the intestine to form retinol, or by plant carotenoids. More than 600 carotenoids have been identified in nature, of which 50 to 60 possess provitamin A properties and 10 have nutritional relevance (De Flora et al., 1999). 

The major dietary sources for preformed vitamin A are vertebrate animal products that are rich in vitamin A esters (liver, kidney, oil, dairy products, and eggs). Liver and oil, particularly from fish, are the major dietary sources of preformed vitamin A. Levels in milk and eggs depend on dietary retinoid and carotenoid intake. Freshwater fish are a source of vitamin A2 (3,4-dehydroretinol), which shows reduced vitamin A activity. Levels of retinal in food are very low, whereas retinoic acid has not been found. 

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. 

Vitamin A activity is expressed as USP units, international units (lU). retinol equivalents (RE), and arotene equivalents. The USP units and lU are equivalent. Each unit ex-pre.sses the activity of 0.3 /ug of all-/rans-retinol. Thus. I mg of all-/rufis-retinol has the activity of 3.333 unit.s. Other equivalents are li.sted in Table 26-3. One RE represents the biological activity of I /7g of all-rnin.t-relinol, 6 /ug of carotene. and 12 /rg of mixed dietary carotenoids. The RE i.s u.sed to convert all dietary sources of vitamin A into a single unit for easy comparison."... 

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,... 

Vitamin A and the associated carotenoids not only reduce the risk of cancer but also strongly inhibit tissue oxidation and free radical damage. Dietary sources of Vitamin A and carotenoids include fish liver oils, dark green leafy vegetables, yellow and red vegetables, beets, spirulina, and garlic. 

Carotenoids are synthesised de novo by all photosynthetic organisms including higher plants, phytoplankton and phototrophic bacteria as well as by certain other bacteria, yeasts and fungi. Carotenoids are selectively absorbed and metabolically modified in the food chain [17]. Animals cannot synthesise carotenoids de novo, but may contain specific carotenoids derived from dietary sources. 

Vitamin Ai (retinol, 13) is essential for the visual process and for normal growth and development of human beings. Carotenoids are the main dietary source of vitamin Aj. As provitamins Ai serve particularly 13-carotene (1) and also carotenoids with one molecular half of (3-carotene (1) intact [24,25]. 

Because astaxanthin has not typically been identified as a major carotenoid in human seram, information on its epidemiology in human health is lacking. Salmon, the principal dietary source of astaxanthin, is an important component of the traditional diets of Eskimos and certain coastal tribes in North America these groups have shown unusually low prevalence of cancer. This low cancer incidence has been attributed to the high levels in salmon of certain fatty acids, notably eicosapentenoic acid (EPA), yet it is possible that astaxanthin has played a role in cancer chemoprevention among these peoples as well. Regardless, the existing data on the potential for astaxanthin to directly prevent cancer is limited to in vitro cell culture studies and in vivo studies with rodent models. 

The dietary source of vitamin A-active substances for herbivores and carnivores is provided, respectively, by carotenoids and by retinol and its esters. But for omnivores such as man, the proportionate contribution of each to habitual diets varies widely, as does the absolute quantity. In the FAO/WHO report of 1967, the lowest intakes of foods with vitamin A activity were said to be in the Near East, Asia, and the Far East, intermediate intakes in Latin America and... 

Serum levels of total carotenoids in the absence of retinol levels are not useful for assessing vitamin A status of individuals or populations because they reflect the level of immediate dietary intake (Clausen and McCoord, 1938 WHO, 1976, 1982). Furthermore, as shown in Table IX, as much as two-thirds or more of the total carotenoids may be non-vitamin A-active compounds (Buzina etaL, 1971). The seasonal effect of carotenoid intake on plasma vitamin A and carotenoid levels is illustrated in Fig. 4. An exception may be among populations, especially children, where malnutrition is prevalent and essentially all the dietary vitamin A throughout the year comes from carotenoid sources (Le Francois et aL, 1980). In this special circumstance when dietary sources of both vitamin A and carotenoids are low, a low carotene value in blood is evidence for inadequate vitamin A status. But in the absence of a serum vitamin A level, a low carotene level may reflect either an inadequate amount in the diet or malabsorption, and without additional supportive evidence cannot be interpreted to reflect poor vitamin A status (Arroyave et al., 1982). 

Effect of Dietary Source of Retinol Equivalents (RE), Preformed versus Precursor, on Plasma Levels of Vitamin A and Carotenoids in Senegal" and the United States ... 

See also Antioxidants Observational Studies Intervention Studies. Ascorbic Acid Physiology, Dietary Sources and Requirements. Carotenoids Chemistry, Sources and Physiology Epidemiology of Health Effects. Copper. Folic Acid. Riboflavin. Selenium. Vitamin E Physiology and Health Effects. Zinc Physiology. 

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... 

See also Antioxidants Diet and Antioxidant Defense Observationai Studies Intervention Studies. Carotenoids Chemistry, Sources and Physioiogy. Coronary Heart Disease Prevention. Lycopenes and Reiated Compounds. Phytochemicais Epidemioiogicai Factors. Suppiementation Dietary Suppiements. 

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