Cancer, carotene lycopene

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. ... 

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. 

Carotenoids are a class of lipophilic compounds with a polyisoprenoid structure. Most carotenoids contain a series of conjugated double bonds, which are sensitive to oxidative modification and cis-trans isomerization. There are six major carotenoids (ji-carotenc, a-carotene, lycopene, P-cryptoxanthin, lutein, and zeaxanthin) that can be routinely found in human plasma and tissues. Among them, p-carotene has been the most extensively studied. More recently, lycopene has attracted considerable attention due to its association with a decreased risk of certain chronic diseases, including cancers. Considerable efforts have been expended in order to identify its biological and physiochemical properties. Relative to P-carotene, lycopene has the same molecular mass and chemical formula, yet lycopene is an open-polyene chain lacking the P-ionone ring structure. While the metabolism of P-carotene has been extensively studied, the metabolism of lycopene remains poorly understood. 

Daucus carota L. subsp. sative Hoffm. Nan He Chi (Carrot) (whole plant) Carotenes, lycopene, phytofluere, umbelliferone, alpha-pinene, camphene, myrcene, daucol, alpha-phellandrene, bisabolene, luteolin-7-glucoside, daucine, pyrrolidine, geraniol, citronellol, carotol, citral, caryophyllene, p-cymene, asarone, daucosterol, petroselinic acid.48 For chronic dysentery, worms, carminative, diuretic, emmenagogue, lower blood sugar, prevent cancer, diabetes, dyspepsia and gout. 

Numerous studies have demonstrated an inverse correlation between cancer rates and dietary intake of various antioxidants (foods rich in vitamins C and E, beta-carotene, lycopene, etc.) (Cl3, G5, E3, P2, H10, Y5). For example, a recent review (G8) showed a consistently lower risk of developing a variety of cancers in those with a higher consumption of tomatoes and tomato-based products (rich in lycopene, a potent carotenoid antioxidant), adding further support for the current recommendations to increase the consumption of fruits and vegetables. In addition... 

Narisawa, T. et al.. Inhibitory effects of natural carotenoids, a-carotene, P-carotene, lycopene, and lutein, on colonic aberrant crypt foci formation in rats. Cancer Lett., 107, 137, 1996. 

Tomatoes contain many compounds of carbon, including some that have properties that help people stay healthy. Two of these compounds are lycopene and beta-carotene. Lycopene gives tomatoes their red color and is believed to help prevent heart disease and some forms of cancer. In the human body, beta-carotene is converted to vitamin A, an essential nutrient. 

Antioxidants derived from foods help to protect against free radical damage. Carotenoids are a very important class of antioxidants, as are vitamins A, C, and E. Carotenoids, including alpha carotene, beta carotene, lycopene, lutein, and zexanthin, have been demonstrated to protect against skin cancer, prostate cancer, and atherosclerosis, among others. Higher blood antioxidant levels have been correlated with lower blood levels of C-reactive protein (CRP), and thus lower inflammation of the blood vessels (and less atherosclerotic plaque). 

A predominantly plant-based diet reduces the risk of developing several chronic diseases, including cancer and cardiovascular disease (CVD) coronary heart disease and stroke. It is often assumed that antioxidants, including vitamin C, vitamin E, the carotenoids (e.g., / -carotene, lycopene, and lutein), selenium, and the flavonoids (e.g., quercetin. 

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. 

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. 

Other dietary factors implicated in prostate cancer include retinol, carotenoids, lycopene, and vitamin D consumption.5,6 Retinol, or vitamin A, intake, especially in men older than age 70, is correlated with an increased risk of prostate cancer, whereas intake of its precursor, [3-carotene, has a protective or neutral effect. Lycopene, obtained primarily from tomatoes, decreases the risk of prostate cancer in small cohort studies. The antioxidant vitamin E also may decrease the risk of prostate cancer. Men who developed prostate cancer in one cohort study had lower levels of l,25(OH)2-vitamin D than matched controls, although a prospective study did not support this.2 Clearly, dietary risk factors require further evaluation, but because fat and vitamins are modifiable risk factors, dietary intervention may be promising in prostate cancer prevention. 

Levy, J., E. Bosin, B. Feldman et al. 1995. Lycopene is a more potent inhibitor of human cancer cell proliferation than either alpha-carotene or beta-carotene. Nutr Cancer 24(3) 257-266. 

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