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Julie A Howe - One of the best experts on this subject based on the ideXlab platform.

  • β cryptoxanthin from supplements or carotenoid enhanced maize maintains liver vitamin a in mongolian gerbils meriones unguiculatus better than or equal to β carotene supplements
    British Journal of Nutrition, 2008
    Co-Authors: Hua Jing, Julie A Howe
    Abstract:

    Maize with enhanced provitamin A carotenoids (biofortified), accomplished through conventional plant breeding, maintains vitamin A (VA) status in Mongolian gerbils (Meriones unguiculatus). Two studies in gerbils compared the VA value of Beta-Cryptoxanthin with beta-carotene. Study 1 (n 47)examined oil supplements and study 2 (n 46) used maize with enhanced Beta-Cryptoxanthin and beta-carotene. After 4 weeks' depletion, seven or six gerbils were killed; remaining gerbils were placed into weight-matched groups of 10. In study 1, daily supplements were cottonseed oil, and 35, 35 or 17.5 nmol VA (retinyl acetate), Beta-Cryptoxanthin or beta-carotene, respectively, for 3 weeks. In study 2, one group of gerbils was fed a 50% biofortified maize diet which contained 2.9 nmol Beta-Cryptoxanthin and 3.2 nmol beta-carotene/g feed. Other groups were given equivalent b-carotene or VA supplements based on prior-day intake from the biofortified maize or oil only for 4 weeks. In study 1, liver retinol was higher in the VA (0.74 (SD 0.11) micromol) and Beta-Cryptoxanthin (0.5 (SD 0.10) micromol) groups than in the beta-carotene (0.49 (SD 0.13) micromol) and control (0.41 (SD 0.16) micromol)groups (P<0.05). In study 2, the VA (1.17 (SD 0.19) micromol) and maize (0.71 (SD 0.18) micromol) groups had higher liver retinol than the control (0.42 (SD 0.16) micromol) group (P<0.05), whereas the beta-carotene (0.57 (SD 0.21) micromol) group did not. Bioconversion factors (i.e. 2.74 microg Beta-Cryptoxanthin and 2.4 microg beta-carotene equivalents in maize to 1 microg retinol) were lower than the Institute of Medicine values.

  • the xanthophyll composition of biofortified maize zea mays sp does not influence the bioefficacy of provitamin a carotenoids in mongolian gerbils meriones unguiculatus
    Journal of Agricultural and Food Chemistry, 2008
    Co-Authors: Christopher R Davis, Torbert Rocheford, Julie A Howe, Sherry A. Tanumihardjo
    Abstract:

    Maize has been targeted for biofortification with provitamin A carotenoids through traditional breeding. Two studies were conducted in gerbils to evaluate factors that may affect provitamin A activity. Maize diets had equal theoretical concentrations of vitamin A (VA) assuming 100% bioefficacy. Study 1 ( n = 57) varied the ratio of Beta-Cryptoxanthin and beta-carotene but maintained the same theoretical VA. Study 2 ( n = 67) varied lutein and zeaxanthin. Other treatments were oil, VA, or beta-carotene doses. Serum and livers were analyzed for VA and carotenoids. In study 1, total liver VA did not differ among the maize groups. In study 2, total liver VA of the VA and maize groups were higher than controls ( P < 0.05). Conversion factors were 2.1-3.3 mug beta-carotene equivalents to 1 mug retinol. Twice the molar amount of Beta-Cryptoxanthin was as efficacious as beta-carotene and the proportion of Beta-Cryptoxanthin or xanthophylls did not appreciably change the VA value of biofortified maize.

  • evaluation of analytical methods for carotenoid extraction from biofortified maize zea mays sp
    Journal of Agricultural and Food Chemistry, 2006
    Co-Authors: Julie A Howe, Sherry A. Tanumihardjo
    Abstract:

    Biofortification of maize with beta-carotene has the potential to improve vitamin A status in vitamin A deficient populations where maize is a staple crop. Accurate assessment of provitamin A carotenoids in maize must be performed to direct breeding efforts. The objective was to evaluate carotenoid extraction methods and determine essential steps for use in countries growing biofortified maize. The most reproducible method based on coefficient of variation and extraction efficiency was a modification of Kurilich and Juvik (1999). Heat and saponification are required to release carotenoids from biofortified maize and remove oils interfering with chromatographic analysis. For maize samples with high oil content, additional base may be added to ensure complete saponification without compromising results. Degradation of internal standard before carotenoids were released from the maize matrix required the addition of internal standard after heating to prevent overestimation of carotenoids. This modified method works well for lutein, zeaxanthin, Beta-Cryptoxanthin, alpha-carotene, and beta-carotene.

Sherry A. Tanumihardjo - One of the best experts on this subject based on the ideXlab platform.

  • Serum Carotenoids Reveal Poor Fruit and Vegetable Intake among Schoolchildren in Burkina Faso
    MDPI AG, 2018
    Co-Authors: Jean Fidèle Bationo, Augustin N. Zeba, Souheila Abbeddou, Nadine D. Coulibaly, Olivier O. Sombier, Jesse Sheftel, Imael Henri Nestor Bassole, Nicolas Barro, Jean Bosco Ouedraogo, Sherry A. Tanumihardjo
    Abstract:

    The health benefits of fruits and vegetables are well-documented. Those rich in provitamin A carotenoids are good sources of vitamin A. This cross-sectional study indirectly assessed fruit and vegetable intakes using serum carotenoids in 193 schoolchildren aged 7 to 12 years in the Western part of Burkina Faso. The mean total serum carotenoid concentration was 0.23 ± 0.29 µmol/L, which included α- and β-carotene, lutein, and β-cryptoxanthin, and determined with serum retinol concentrations in a single analysis with high performance liquid chromatography. Serum retinol concentration was 0.80 ± 0.35 µmol/L with 46% of children (n = 88) having low values <0.7 µmol/L. Total serum carotene (the sum of α- and β-carotene) concentration was 0.13 ± 0.24 µmol/L, well below the reference range of 0.9–3.7 µmol carotene/L used to assess habitual intake of fruits and vegetables. Individual carotenoid concentrations were determined for α-carotene (0.01 ± 0.05 µmol/L), β-carotene (0.17 ± 0.24 µmol/L), β-cryptoxanthin (0.07 ± 0.06 µmol/L), and lutein (0.06 ± 0.05 µmol/L). These results confirm the previously measured high prevalence of low serum vitamin A concentrations and adds information about low serum carotenoids among schoolchildren suggesting that they have low intakes of provitamin A-rich fruits and vegetables

  • the xanthophyll composition of biofortified maize zea mays sp does not influence the bioefficacy of provitamin a carotenoids in mongolian gerbils meriones unguiculatus
    Journal of Agricultural and Food Chemistry, 2008
    Co-Authors: Christopher R Davis, Torbert Rocheford, Julie A Howe, Sherry A. Tanumihardjo
    Abstract:

    Maize has been targeted for biofortification with provitamin A carotenoids through traditional breeding. Two studies were conducted in gerbils to evaluate factors that may affect provitamin A activity. Maize diets had equal theoretical concentrations of vitamin A (VA) assuming 100% bioefficacy. Study 1 ( n = 57) varied the ratio of Beta-Cryptoxanthin and beta-carotene but maintained the same theoretical VA. Study 2 ( n = 67) varied lutein and zeaxanthin. Other treatments were oil, VA, or beta-carotene doses. Serum and livers were analyzed for VA and carotenoids. In study 1, total liver VA did not differ among the maize groups. In study 2, total liver VA of the VA and maize groups were higher than controls ( P < 0.05). Conversion factors were 2.1-3.3 mug beta-carotene equivalents to 1 mug retinol. Twice the molar amount of Beta-Cryptoxanthin was as efficacious as beta-carotene and the proportion of Beta-Cryptoxanthin or xanthophylls did not appreciably change the VA value of biofortified maize.

  • evaluation of analytical methods for carotenoid extraction from biofortified maize zea mays sp
    Journal of Agricultural and Food Chemistry, 2006
    Co-Authors: Julie A Howe, Sherry A. Tanumihardjo
    Abstract:

    Biofortification of maize with beta-carotene has the potential to improve vitamin A status in vitamin A deficient populations where maize is a staple crop. Accurate assessment of provitamin A carotenoids in maize must be performed to direct breeding efforts. The objective was to evaluate carotenoid extraction methods and determine essential steps for use in countries growing biofortified maize. The most reproducible method based on coefficient of variation and extraction efficiency was a modification of Kurilich and Juvik (1999). Heat and saponification are required to release carotenoids from biofortified maize and remove oils interfering with chromatographic analysis. For maize samples with high oil content, additional base may be added to ensure complete saponification without compromising results. Degradation of internal standard before carotenoids were released from the maize matrix required the addition of internal standard after heating to prevent overestimation of carotenoids. This modified method works well for lutein, zeaxanthin, Beta-Cryptoxanthin, alpha-carotene, and beta-carotene.

Demetrius Albanes - One of the best experts on this subject based on the ideXlab platform.

  • dietary carotenoids serum beta carotene and retinol and risk of lung cancer in the alpha tocopherol beta carotene cohort study
    American Journal of Epidemiology, 2002
    Co-Authors: Crystal N Holick, Dominique S Michaud, Rachael Z Stolzenbergsolomon, Susan T Mayne, Pirjo Pietinen, Philip R Taylor, Jarmo Virtamo, Demetrius Albanes
    Abstract:

    Findings from several beta-carotene supplementation trials were unexpected and conflicted with most observational studies. Carotenoids other than beta-carotene are found in a variety of fruits and vegetables and may play a role in this important malignancy, but previous findings regarding the five major carotenoids are inconsistent. The authors analyzed the associations between dietary beta-carotene, beta-carotene, lutein/zeaxanthin, lycopene, Beta-Cryptoxanthin, vitamin A, serum beta-carotene, and serum retinol and the lung cancer risk in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study cohort of male smokers conducted in southwestern Finland between 1985 and 1993. Of the 27,084 male smokers aged 50-69 years who completed the 276-food item dietary questionnaire at baseline, 1,644 developed lung cancer during up to 14 years of follow-up. Cox proportional hazards models were used to estimate relative risks and 95% confidence intervals. Consumption of fruits and vegetables was associated with a lower lung cancer risk (relative risk = 0.73, 95% confidence interval: 0.62, 0.86, highest vs. lowest quintile). Lower risks of lung cancer were observed for the highest versus the lowest quintiles of lycopene (28%), lutein/zeaxanthin (17%), Beta-Cryptoxanthin (15%), total carotenoids (16%), serum beta-carotene (19%), and serum retinol (27%). These findings suggest that high fruit and vegetable consumption, particularly a diet rich in carotenoids, tomatoes, and tomato-based products, may reduce the risk of lung cancer.

  • effects of supplemental beta carotene cigarette smoking and alcohol consumption on serum carotenoids in the alpha tocopherol beta carotene cancer prevention study
    The American Journal of Clinical Nutrition, 1997
    Co-Authors: Demetrius Albanes, Pirjo Pietinen, Philip R Taylor, Jarmo Virtamo, Matti Rautalahti, O P Heinonen
    Abstract:

    We determined whether serum carotenoid or retinol concentrations were altered by p-carotene supplementation in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study and whether such effects were modified by alcohol consumption or cigarette use. Participants in this substudy were 491 randomly selected men aged 58-76 y from the metropolitan Helsinki study center [237 receiving supplemental β-carotene (20 mg/d) and 254 not receiving such supplementation]. Dietary carotenoids, retinol, and alcohol, and serum β-carotene, α-tocopherol, retinol, and cholesterol were assessed at baseline. After an average of 6.7 y of supplementation, serum was collected and carotenoid, retinol, and α-tocopherol concentrations were determined by HPLC. Serum carotenoid fractions were highly correlated with each other (P ≤ 0.001). Compared with the unsupplemented group, the β-carotene group had significantly higher serum concentrations of β-carotene (1483%), α-carotene (145%), and β-cryptoxanthin (67%) (P ≤ 0.0001). Retinol concentrations were 6% higher (P = 0.03) and lutein was 11% lower (P = 0.02) in the supplemented group. Serum lycopene, zeaxanthin, and α-tocopherol did not differ according to β-carotene-supplementation status. Although these β-carotene-group differences were not significantly altered by amount of alcohol consumption, higher consumption (> 12.9 g/d, median) was related to lower (10-38%) concentrations of carotenoids, particularly β-carotene, α-carotene, and β-cryptoxanthin, in both the supplemented and unsupplemented groups. Smoking status did not significantly influence the supplementation-related differences in serum carotenoid and retinol values but concentrations of carotenoids were generally highest in participants who quit smoking while in the study and lowest in current smokers of ≥20 cigarettes/d. This study showed that serum concentrations of non-β-carotene carotenoids are altered by long-term β-carotene supplementation and confirms the adverse effects of alcohol and cigarette smoking on serum carotenoids.

Edward P Norkus - One of the best experts on this subject based on the ideXlab platform.

  • prospective study of antioxidant micronutrients in the blood and the risk of developing prostate cancer
    American Journal of Epidemiology, 2003
    Co-Authors: Hanyao Huang, Edward P Norkus, Anthony J. Alberg, George W. Comstock, Sandra C Hoffman, Kathy J Helzlsouer
    Abstract:

    Antioxidant micronutrients may have chemopreventive effects. The authors examined the associations between prediagnostic blood levels of micronutrients and prostate cancer risk in two nested case-control studies of 9,804 and 10,456 male residents of Washington County, Maryland, who donated blood in 1974 (CLUE I) and 1989 (CLUE II), respectively. Until 1996, 182 men for whom adequate serum remained for assays in the CLUE I cohort and 142 men in the CLUE II cohort developed prostate cancer. Each case was matched with two controls by age, gender, race, and date of blood donation. In both cohorts, cases and controls had similar concentrations of alpha-carotene, beta-carotene, total carotene, Beta-Cryptoxanthin, lutein, lycopene, retinol, and ascorbic acid; serum alpha-tocopherol was weakly associated with prostate cancer risk. Higher retinyl palmitate concentrations were associated with a lower risk in CLUE I but not CLUE II. In CLUE I, cases had lower concentrations of gamma-tocopherol than did controls (p = 0.02), but no dose-response trend was observed. A strong inverse association between gamma-tocopherol and prostate cancer risk was observed in CLUE II. Findings do not replicate previous reports of a protective association between lycopene and prostate cancer, but they suggest potential chemopreventive effects of gamma-tocopherol on prostate cancer.

  • smoking and exposure to environmental tobacco smoke decrease some plasma antioxidants and increase γ tocopherol in vivo after adjustment for dietary antioxidant intakes
    The American Journal of Clinical Nutrition, 2003
    Co-Authors: Marion Dietrich, Edward P Norkus, Gladys Block, Mark Hudes, Maret G Traber, Carroll E Cross, Lester Packer
    Abstract:

    BACKGROUND: Free radicals in cigarette smoke may cause oxidative damage to macromolecules, contributing to cardiovascular diseases and cancer. Decreased plasma antioxidant concentrations may indicate cigarette smoke-related oxidative stress. OBJECTIVE: We compared the effects on plasma antioxidant concentrations in cotinine-confirmed active and passive smokers with those in nonsmokers, independent of differences in dietary intakes and other covariates. DESIGN: Plasma samples from 83 smokers, 40 passive smokers, and 36 nonsmokers were analyzed for total ascorbic acid, alpha- and gamma-tocopherols, 5 carotenoids, retinol, and cotinine. Groups were compared by using analysis of variance with adjustment for sex, age, race, body mass index, alcohol intake, triacylglycerol concentration, fruit and vegetable intakes, and dietary antioxidants. RESULTS: After adjustment for dietary antioxidant intakes and other covariates, smokers and passive smokers had significantly lower plasma beta-carotene concentrations than did nonsmokers (0.15, 0.17, and 0.24 micro mol/L, respectively) and significantly higher gamma-tocopherol concentrations (7.8, 7.8, and 6.5 micro mol/L, respectively). Smokers had significantly lower plasma ascorbic acid and Beta-Cryptoxanthin concentrations than did nonsmokers and passive smokers (ascorbic acid: 43.6, 54.5, and 54.6 micro mol/L, respectively; Beta-Cryptoxanthin: 0.12, 0.16, and 0.16 micro mol/L, respectively) and significantly lower concentrations of lutein and zeaxanthin than did nonsmokers (0.33 compared with 0.41 micro mol/L). The P values for all the differences described above were < 0.05. No significant differences in plasma concentrations of alpha-tocopherol, alpha-carotene, total carotenoids, lycopene, or retinol were observed. CONCLUSIONS: These results indicate that cigarette smokers and nonsmokers exposed to cigarette smoke have a significantly lower plasma antioxidant status than do unexposed nonsmokers, independent of differences in dietary antioxidant intakes. Further research is required to explain why plasma gamma-tocopherol concentrations were significantly higher in smokers and passive smokers than in nonsmokers.

  • which plasma antioxidants are most related to fruit and vegetable consumption
    American Journal of Epidemiology, 2001
    Co-Authors: Gladys Block, Edward P Norkus, Mark Hudes, Shelly Mandel, Kathy J Helzlsouer
    Abstract:

    Substantial evidence suggests that fruit and vegetable intake reduces the risk of some cancers and other chronic diseases. While a varied diet containing fruits and vegetables may confer benefits greater than those of any single nutrient, it would be useful to have data on the plasma nutrients most influenced by fruit and vegetable intake. The authors examined the correlation between fruit and vegetable intake as measured by the abbreviated CLUE II food frequency questionnaire and several plasma antioxidants. This study includes 116 male subjects aged 35-72 years who were nonsmokers and nonusers of vitamin supplements and who provided blood samples in the CLUE II Study in Washington County, Maryland. Plasma was assayed for ascorbic acid, beta-carotene, Beta-Cryptoxanthin, and alpha- and gamma-tocopherol. Lipid- and energy-adjusted partial correlation for the relation with fruit and vegetable intake was r = 0.64 for ascorbic acid, r = 0.44 for beta-carotene, and r = 0.50 for Beta-Cryptoxanthin. While this study does not address efficacy, the stronger association of ascorbic acid with fruit and vegetable intake seen here may imply that ascorbic acid is an important component of the protective effect seen for fruits and vegetables in numerous epidemiologic studies.

  • the risk of developing lung cancer associated with antioxidants in the blood ascorbic acid carotenoids alpha tocopherol selenium and total peroxyl radical absorbing capacity
    Cancer Epidemiology Biomarkers & Prevention, 1997
    Co-Authors: George W. Comstock, A E Burke, S C Hoffman, Edward P Norkus, Richard G Cutler, Myron D Gross, Anthony J. Alberg, Hanyao Huang, K Wu, J. S. Morris
    Abstract:

    Lung cancer cases diagnosed during the period 1975 through 1993 and matched controls were identified in the rosters of Washington County, Maryland residents who had donated blood for a serum bank in 1974 or 1989. Plasma from participants in the 1989 project was assayed for ascorbic acid; serum or plasma was assayed for participants in either project for alpha- and beta-carotene, cryptoxanthin, lutein/zeaxanthin, lycopene, alpha-tocopherol, selenium, and peroxyl radical absorption capacity. Among the total group of 258 cases and 515 controls, serum/plasma concentrations were significantly lower among cases than controls for cryptoxanthin, beta-carotene, and lutein/zeaxanthin with case-control differences of -25.5, -17.1, and -10.1%, respectively. Modest nonsignificant case-control differences in a protective direction were noted for alpha-carotene and ascorbic acid. There were only trivial differences for lycopene, alpha-tocopherol, selenium, and peroxyl radical absorption capacity. Findings are reported for males and females and for persons who had never smoked cigarettes, former smokers, and current smokers at baseline. These results and those from previous studies suggest that beta-carotene is a marker for some protective factor(s) against lung cancer; that cryptoxanthin, alpha-carotene, and ascorbic acid need to be investigated further as potentially protective factors or associates of a protective factor; and that lycopene, alpha-tocopherol, selenium, and peroxyl radical absorption capacity are unlikely to be associated with lung cancer risk. Until specific preventive factors are identified, the best protection against lung cancer is still the avoidance of airborne carcinogens, especially tobacco smoke; second best is the consumption of a diet rich in fruits and vegetables.

Kathy J Helzlsouer - One of the best experts on this subject based on the ideXlab platform.

  • prospective study of antioxidant micronutrients in the blood and the risk of developing prostate cancer
    American Journal of Epidemiology, 2003
    Co-Authors: Hanyao Huang, Edward P Norkus, Anthony J. Alberg, George W. Comstock, Sandra C Hoffman, Kathy J Helzlsouer
    Abstract:

    Antioxidant micronutrients may have chemopreventive effects. The authors examined the associations between prediagnostic blood levels of micronutrients and prostate cancer risk in two nested case-control studies of 9,804 and 10,456 male residents of Washington County, Maryland, who donated blood in 1974 (CLUE I) and 1989 (CLUE II), respectively. Until 1996, 182 men for whom adequate serum remained for assays in the CLUE I cohort and 142 men in the CLUE II cohort developed prostate cancer. Each case was matched with two controls by age, gender, race, and date of blood donation. In both cohorts, cases and controls had similar concentrations of alpha-carotene, beta-carotene, total carotene, Beta-Cryptoxanthin, lutein, lycopene, retinol, and ascorbic acid; serum alpha-tocopherol was weakly associated with prostate cancer risk. Higher retinyl palmitate concentrations were associated with a lower risk in CLUE I but not CLUE II. In CLUE I, cases had lower concentrations of gamma-tocopherol than did controls (p = 0.02), but no dose-response trend was observed. A strong inverse association between gamma-tocopherol and prostate cancer risk was observed in CLUE II. Findings do not replicate previous reports of a protective association between lycopene and prostate cancer, but they suggest potential chemopreventive effects of gamma-tocopherol on prostate cancer.

  • which plasma antioxidants are most related to fruit and vegetable consumption
    American Journal of Epidemiology, 2001
    Co-Authors: Gladys Block, Edward P Norkus, Mark Hudes, Shelly Mandel, Kathy J Helzlsouer
    Abstract:

    Substantial evidence suggests that fruit and vegetable intake reduces the risk of some cancers and other chronic diseases. While a varied diet containing fruits and vegetables may confer benefits greater than those of any single nutrient, it would be useful to have data on the plasma nutrients most influenced by fruit and vegetable intake. The authors examined the correlation between fruit and vegetable intake as measured by the abbreviated CLUE II food frequency questionnaire and several plasma antioxidants. This study includes 116 male subjects aged 35-72 years who were nonsmokers and nonusers of vitamin supplements and who provided blood samples in the CLUE II Study in Washington County, Maryland. Plasma was assayed for ascorbic acid, beta-carotene, Beta-Cryptoxanthin, and alpha- and gamma-tocopherol. Lipid- and energy-adjusted partial correlation for the relation with fruit and vegetable intake was r = 0.64 for ascorbic acid, r = 0.44 for beta-carotene, and r = 0.50 for Beta-Cryptoxanthin. While this study does not address efficacy, the stronger association of ascorbic acid with fruit and vegetable intake seen here may imply that ascorbic acid is an important component of the protective effect seen for fruits and vegetables in numerous epidemiologic studies.