zeaxanthin and Colonic-Neoplasms

The intra- and interindividual variations and season and center effects were estimated from a series of serum carotenoid concentrations in the Polyp Prevention Trial (PPT) participants.. Fasting blood was collected annually for 4 years in all 1905 participants, and a subcohort of 901 participants were selected within each (of eight) center(s), by gender and dietary arm of the study, for measurement of five major carotenoid peaks. Using variance of component methods, the variation in serum carotenoid concentrations about the underlying mean was partitioned into explanatory components attributed to various sources.. The contributions of the inter- and intraindividual variances to the overall variation in carotenoid concentrations were in the range of 61-70 and 20-35%, respectively, whereas center and center-by-season effects provided 2.6-9.5 and 0.2-1.4%, respectively. The highest percent (35%) of intraindividual variation was exhibited by lycopene, and the highest percent (70% apiece) of interindividual variation was exhibited by lutein/zeaxanthin and beta-carotene. Serum lycopene had the highest ratio of intra- to interindividual variation of 0.57, whereas lutein had the lowest ratio of 0.29. We estimate that the ratio of intra- to interindividual variance around the mean carotenoid concentration can be reduced greatly by collecting 3-4 compared to 1 blood measurement in large-scale trials like the PPT.. In the largest study of components of variation in individuals at high risk for colorectal cancer, the largest contributors to variation in serum carotenoid concentrations were intra- and interindividual effects followed by center and center-by-season effects.

Topics: Adenoma; beta Carotene; Carotenoids; Colonic Neoplasms; Cryptoxanthins; Diet; Female; Humans; Lutein; Lycopene; Male; Middle Aged; Neoplasm Recurrence, Local; Risk Factors; Seasons; Xanthophylls; Zeaxanthins

Two cell lines, human normal colon epithelial cells (CCD 841 CoTr) and human colon adenocarcinoma cells (HT-29) were cultured in the presence of exogenous carotenoids, either zeaxanthin or lutein. Both carotenoids demonstrated cytotoxicity with respect to cancer cells but not to normal cells. Cells from both the cell lines were analyzed with application of fluorescence lifetime imaging microscopy and Raman scattering microscopy. Both imaging techniques show effective incorporation of carotenoid molecules into growing cells. Comparison of the Raman scattering and fluorescence lifetime characteristics reveals different molecular organization of carotenoids in the carcinoma and normal cells. The main difference consists in a carotenoid aggregation level which is substantially lower in the carcinoma cells as compared to the normal cells. Different molecular organization of carotenoids was interpreted in terms of a different metabolism of normal and carcinoma cells and has been concluded to provide a possibility of cancer diagnosis based on spectroscopic analyses.

Topics: Adenocarcinoma; Carotenoids; Cell Line, Tumor; Cell Survival; Colon; Colonic Neoplasms; Epithelial Cells; Fluorescence; Humans; Image Processing, Computer-Assisted; Lutein; Spectrum Analysis, Raman; Zeaxanthins

Zeaxanthin (Zea) and lutein are the only dietary carotenoids that accumulate in the macular region of the retina and lens. It was proposed that these carotenoids protect these tissues against photooxidative damage. Few plant foods are enriched in Zea, and information about the bioavailability of Zea from these foods and its accumulation in ocular tissues is limited. The amounts of free Zea and its mono- and diesters were measured for several plant foods that have relatively high concentrations of this xanthophyll. Wolfberry had the greatest concentration of Zea with a diester that accounts for 95% of the total. Free, mono-, and diesters of Zea were present in orange and red peppers, whereas only Zea monoesters were detected in squash. Zea esters were partially hydrolyzed by carboxyl ester lipase (CEL) during simulated digestion. The efficiency of micellarization was dependent on speciation with combined means of free Zea, Zea monoesters, Zea diesters from the digested foods of 81 +/- 8, 44 +/- 5, and 11 +/- 4%, respectively. When exposed to micelles generated during digestion of the test foods, Zea uptake by Caco-2 cells was proportional to the medium content (11-14%). Free Zea was the most abundant form in Caco-2 cells, although Zea monoesters also were detected (<8 +/- 0.7% vs. free Zea). CEL enhanced Zea uptake from micelles (12.3-fold; P < 0.05) by hydrolyzing Zea esters. After cell uptake, concentrations of free and monoesterified Zea remained relatively stable. These data suggest that dietary Zea esters are hydrolyzed by CEL during the small intestinal phase of digestion and that this conversion enhances Zea bioavailability.

Topics: beta Carotene; Biological Transport; Carboxylesterase; Cell Line, Tumor; Colonic Neoplasms; Digestion; Food Analysis; Humans; Hydrolysis; Micelles; Palmitates; Xanthophylls; Zeaxanthins

Some epidemiological studies suggest that consumption of fruits and vegetables with a high carotenoid content may protect against colon cancer (CC). The evidence, however, is not completely consistent. Given the inconsistencies in findings in previous studies and continued interest in identifying modifiable risk factors for CC, a case-control study of French-Canadian in Montreal, Canada, was undertaken to examine the possible association between dietary carotenoids and CC risk and to investigate whether this association varies in relation to lifestyle factors such as smoking or diet, and particularly the high consumption of long-chain polyunsaturated fatty acids (LCPUFA). A total of 402 colorectal cases (200 males and 202 females) and 688 population-based controls matched for age, gender and place of residence were interviewed. Dietary intake was assessed through a validated food frequency questionnaire that collected information on over 200 food items and recipes. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated in unconditional logistic regression models. After adjustment for important variables such as total energy intake, no association was found between dietary intake of carotenoids and CC risk. For women with high intakes of LCPUFA, an inverse association was found between lutein + zeaxanthin and CC risk. ORs were 0.41; 95%CI (0.19-0.91), p=0.03 for eicosapentaenoic acid, and OR=0.36, 95%CI (0.19-0.78), p=0.01 for docosahexaenoic acid, when the upper quartiles of intake were compared to the lower. Among never-smokers, a significantly reduced risk of CC was associated with intake of beta-carotene [OR=0.44, 95%CI (0.21-0.92) and p=0.02], whereas an inverse association was found between lycopene intake and CC risk [OR=0.63, 95%CI (0.40-0.98) and p=0.05] among smokers. The results of our study suggest that a diet rich in both lutein + zeaxanthin and LCPUFAs may help prevent CC in French-Canadian females.

Topics: Adult; Aged; beta Carotene; Carotenoids; Case-Control Studies; Colonic Neoplasms; Docosahexaenoic Acids; Eicosapentaenoic Acid; Fatty Acids, Unsaturated; Female; Humans; Lutein; Male; Middle Aged; Xanthophylls; Zeaxanthins

Carotenoids have numerous biological properties that may underpin a role for them as chemopreventive agents. However, except for beta-carotene, little is known about how dietary carotenoids are associated with common cancers, including colon cancer.. The objective of this study was to evaluate associations between dietary alpha-carotene, beta-carotene, lycopene, lutein, zeaxanthin, and beta-cryptoxanthin and the risk of colon cancer.. Data were collected from 1993 case subjects with first primary incident adenocarcinoma of the colon and from 2410 population-based control subjects. Dietary data were collected from a detailed diet-history questionnaire and nutrient values for dietary carotenoids were obtained from the US Department of Agriculture-Nutrition Coordinating Center carotenoid database (1998 updated version).. Lutein was inversely associated with colon cancer in both men and women [odds ratio (OR) for upper quintile of intake relative to lowest quintile of intake: 0.83; 95% CI: 0.66, 1.04; P = 0.04 for linear trend]. The greatest inverse association was observed among subjects in whom colon cancer was diagnosed when they were young (OR: 0.66; 95% CI: 0.48, 0.92; P = 0.02 for linear trend) and among those with tumors located in the proximal segment of the colon (OR: 0.65; 95% CI: 0.51, 0.91; P < 0.01 for linear trend). The associations with other carotenoids were unremarkable.. The major dietary sources of lutein in subjects with colon cancer and in control subjects were spinach, broccoli, lettuce, tomatoes, oranges and orange juice, carrots, celery, and greens. These data suggest that incorporating these foods into the diet may help reduce the risk of developing colon cancer.

Topics: Adenocarcinoma; Age Factors; Aged; Anticarcinogenic Agents; beta Carotene; Carotenoids; Colonic Neoplasms; Cryptoxanthins; Diet; Diet Surveys; Humans; Lutein; Lycopene; Middle Aged; Phytotherapy; Risk Factors; Smoking; Utah; Vegetables; Xanthophylls; Zeaxanthins

Various natural carotenoids were proven to have anticarcinogenic activity. Epidemiological investigations have shown that cancer risk is inversely related to the consumption of green and yellow vegetables and fruits. Since beta-carotene is present in abundance in these vegetables and fruits, it has been investigated extensively as possible cancer preventive agent. However, various carotenoids which co-exist with beta-carotene in vegetables and fruits also have anti-carcinogenic activity. And some of them, such as alpha-carotene, showed higher potency than beta-carotene to suppress experimental carcinogenesis. Thus, we have carried out more extensive studies on cancer preventive activities of natural carotenoids in foods; i.e., lutein, lycopene, zeaxanthin and beta-cryptoxanthin. Analysis of the action mechanism of these natural carotenoids is now in progress, and some interesting results have already obtained; for example, beta-cryptoxanthin was suggested to stimulate the expression of RB gene, an anti-oncogene, and p73 gene, which is known as one of the p53-related genes. Based on these results, multi-carotenoids (mixture of natural carotenoids) seems to be of interest to evaluate its usefulness for practice in human cancer prevention.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Anticarcinogenic Agents; beta Carotene; Carotenoids; Colonic Neoplasms; Cryptoxanthins; Disease Models, Animal; Fruit; Humans; Lutein; Lycopene; Methylnitrosourea; Mice; Rats; Rats, Inbred F344; Skin Neoplasms; Tetradecanoylphorbol Acetate; Vegetables; Xanthophylls; Zeaxanthins

We determined whether intakes of the main dietary carotenoids (alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein plus zeaxanthin, and lycopene) and of vitamins A, C, and E were associated with the prevalence of colorectal adenomas among male and female members of a prepaid health plan in Los Angeles who underwent sigmoidoscopy (n = 488 matched pairs). Participants, ages 50-74 years, completed a 126-item semiquantitative food-frequency questionnaire and a non-dietary questionnaire from 1991 to 1993. In the univariate-matched analysis, alpha-carotene, beta-carotene (with and without supplements), beta-cryptoxanthin, lutein plus zeaxanthin, vitamin A (with and without supplements), and vitamin C (with and without supplements) were associated with a decreased prevalence of colorectal adenomas. After adjustment for intake of calories, saturated fat, folate, fiber, and alcohol, and for current smoking status, body mass index, race, physical activity, and use of nonsteroidal anti-inflammatory drugs, only beta-carotene including supplements was inversely associated with adenomas (odds ratio (OR), 0.6; 95% confidence interval (CI), 0.41.1; trend, P= 0.04; ORs compare highest to lowest quartiles0; vitamin C showed a weaker inverse association (OR, 0.8; 95% CI, 0.5-1.5; trend, P = 0.08); and the remaining compounds were no longer clearly associated with risk. After including beta-carotene with supplements and vitamin C simultaneously in the mutivariate model, the association of beta-carotene with supplements with adenomas was weakened (OR, 0.8; 95% CI, 0.5-1.3; trend P = 0.15), and vitamin C was no longer associated with risk. These data provide only modest support for a protective association of beta-carotene with colorectal adenomatous polyps.

Topics: Adenoma; Aged; Anticarcinogenic Agents; Ascorbic Acid; beta Carotene; Carotenoids; Case-Control Studies; Colonic Neoplasms; Cryptoxanthins; Diet; Feeding Behavior; Female; Humans; Los Angeles; Lutein; Lycopene; Male; Middle Aged; Multivariate Analysis; Prevalence; Rectal Neoplasms; Risk Factors; Sigmoidoscopy; Vitamin A; Vitamin E; Xanthophylls; Zeaxanthins