Biomedical subjects

B Olmedilla

Publications and source records attributed to B Olmedilla.

29 records · Page 2Linked to original sources

PubMed1998

Oxidative DNA damage measured in human lymphocytes: large differences between sexes and between countries, and correlations with heart disease mortality rates.

The 'antioxidant hypothesis' proposes that vitamin C, vitamin E, carotenoids, and other antioxidants occurring in fruit and vegetables afford protection against heart disease and cancer by preventing oxidative damage to lipids and to DNA, respectively. To test elements of this hypothesis, we have measured blood levels of dietary antioxidants, and 8-oxodeoxyguanosine (8-oxo-dG) concentrations in lymphocyte DNA, in healthy men and women from five European countries: France, Ireland, The Netherlands, Spain, and the U.K. Volunteers, aged 25 45, all nonsmokers, gave blood samples before and after a 12-wk carotenoid supplementation regime. Vitamin C was measured in plasma and vitamin E and carotenoids were measured in serum by high-performance liquid chromatography (HPLC). 8-oxo-dG was assayed by HPLC (with coulometric detection) in DNA isolated from lymphocytes from the same blood samples. Mean values were calculated for groups of volunteers at each sampling time according to country, sex, and supplementation (between 9 and 24 individual samples contributing to each mean). We found that 8-oxo-dG levels in lymphocyte DNA vary significantly according to sex and country. A low mean 8-oxo-dG concentration is seen in DNA of women from all five countries, and of men from France and Spain. 8-oxo-dG is significantly higher (up to about threefold) in lymphocyte DNA from men in Ireland and the U.K. Oxidative DNA damage is not significantly affected by carotenoid supplementation; nor is there any association with mean baseline levels of antioxidants, which are generally similar in the five countries. The five countries sampled lie on an axis from northern to southern Europe with a steep gradient in terms of premature heart disease. There is a strong association between premature coronary heart disease mortality in men and the mean levels of 8-oxo-dG for the five countries (r = 0.95, P < 0.01). Women have low coronary heart disease mortality rates, which do not correlate with 8-oxo-dG. In terms of cancer deaths, only colorectal cancer in men shows a significant positive correlation (r = 0.91, P < 0.05), and stomach cancer in women is negatively correlated with DNA oxidation (r = -0.92, P = 0.01).

8-Hydroxy-2'-Deoxyguanosine↗

PubMed1998

Lutein ester in serum after lutein supplementation in human subjects.

Lutein, one of the major carotenoids present in serum, is also widely consumed by most populations. For the purpose of testing the potential health benefits of several carotenoids, lutein was supplied as part of an intervention trial to test whether the consumption of these food constituents reduces oxidative damage to human tissue components. Lutein from a natural source (15 mg/d as mixed ester forms) was supplied for 4 months to eighteen non-smoking, apparently healthy volunteers (nine men, nine women) aged 25-45 years. The serum carotenoid profile was analysed at baseline and monthly thereafter. On average, lutein concentrations increased 5-fold after the first month of supplementation (mean 1.34 (range 0.6-3.34) mumol/l). On reviewing the results, in those volunteers whose lutein levels surpassed 1.05 mumol/l (fourteen of seventeen), we tentatively identified lutein monopalmitate along with another unidentified ester (possibly from a monoketocarotenoid) in serum. Lutein levels returned to baseline values and ester forms were not present 3 months after supplementation was discontinued. Their concentrations did not correlate with, and represented less than 3% of, lutein levels achieved in serum. They were observed before development of, and despite the presence of, carotenodermia. To our knowledge, this is the first time xanthophyll esters have been described in human serum. In view of the fact that xanthophyll esters have not been previously reported in serum and chylomicrons, it seems unlikely that these ester forms would be a reflection of the contents of the capsule. They may indicate a 'ceiling effect' on or saturation of the transport capacity for xanthophylls, and may have been re-esterified in vivo because of the unusual dietary conditions. The determination of the physiological importance of this finding will require further investigation, although neither haematological nor biochemical changes were detected.

Adult↗

PubMed1997

Supplementation with lutein (4 months) and alpha-tocopherol (2 months), in separate or combined oral doses, in control men.

As part of a European project to test if 'the consumption of diets rich in carotenoids reduces oxidative damage to human tissue components', 15 mg/day lutein and 100 mg/day alpha-tocopherol were supplied to ten volunteers. alpha-Tocopherol (alone and combined) provoked an increase in alpha-tocopherol and a decrease in gamma-tocopherol serum levels. Lutein levels increased during the first month (given alone) in all controls but they behaved very differently during the following 3 months. Ketocarotenoids (not supplied) increased whereas anhydroluteins (not supplied) did not change, suggesting that they are formed in vivo.

Adult↗

PubMed1997

Variability in the intercomparison of food carotenoid content data: a user's point of view.

The availability of reliable information on food composition is essential both for the evaluation of diet and for nutritional research to relate diet to health or disease. In this article, we compare the total and individual carotenoid contents and the retinol equivalents in fruits and vegetables reported in several food composition tables and HPLC studies. The impact of the variability in carotenoid intake was evaluated on the basis of Spanish National Consumption Statistics and on the values for a standard diet. We identify, from a user's point of view, errors concerning identification of the items and the terms used to refer to the compounds. Food composition tables overestimate (by 2 to 48%) the retinol equivalent intake, whereas they underestimate (by 30 to 50%) the total carotenoid intake according to HPLC data. We study the effect of these main sources of error, their impact on dietary assessment and on the classification of relevant contributors, and the possible consequences with respect to proper diet in terms of nutritional assessment and epidemiological studies. Given the different dietary habits among populations and the fact that certain items may be over- or underestimated in databases, the use of a single database may be misleading as to the rate of carotenoid consumption and the "true" nutrient intake in a given population, thus weakening the reliability of the study and resulting in erroneous conclusions.

Carotenoids↗

PubMed1997

Reference values for retinol, tocopherol, and main carotenoids in serum of control and insulin-dependent diabetic Spanish subjects.

To establish reference ranges for use in clinical and epidemiological studies, we determined concentrations of retinol, alpha-tocopherol, beta-carotene, alpha-carotene, beta-cryptoxanthin, lutein, zeaxanthin, and lycopene in 450 Spanish control subjects and 123 Spanish patients with insulin-dependent diabetes mellitus (IDDM). Results were grouped according to sex, and samples were collected throughout the year. Concentrations of retinol were significantly lower and beta-carotene and alpha-carotene were higher in women than in men, both in controls and IDDM subjects, whereas beta-cryptoxanthin concentrations were higher only in control women. Conditional logistic regression analysis showed that retinol, beta-carotene, and lycopene were the variables associated with diabetes. In comparison with other populations, our controls showed, in general, ordinary concentrations of retinol, comparatively low beta-carotene and high beta-cryptoxanthin concentrations, and a relatively high alpha-tocopherol/ cholesterol ratio.

Adolescent↗

PubMed1996

Major fruit and vegetable contributors to the main serum carotenoids in the Spanish diet.

OBJECTIVE: To identify the main sources of serum carotenoids (lutein, zeaxanthin, lycopene, beta-cryptoxanthin, alpha-carotene and beta-carotene) among the fruits and vegetables in the Spanish diet, to be used in the design of food questionnaires and to provide useful information for epidemiological and comparative studies. DESIGN: A Family Budget Survey from the National Institute of Statistics (1990-1991); an open questionnaire dealing with foods consumed over a one-week period; physical amounts consumed annually and during three-month periods. Calculation of the percentage contribution of each food on the basis of a standard portion as well as the carotenoid concentrations previously reported by our laboratory. SETTING: Nationwide (urban and rural). SUBJECTS: Twenty-one thousand, one hundred and fifty-five (21 155) randomly selected, private households throughout Spain (72279 subjects). RESULTS: Nine vegetables (potato, tomato, green bean, green and/or red pepper, carrot, artichoke, spinach, lettuce and beet) and five fruits (orange, tangerine, banana, peach and watermelon) account for more than 96% of the intake of the major six carotenoids in serum, both on a yearly and on a seasonal basis. Fruit and vegetables provide between 3.0mg (in autumn) and 4.3mg (in summer) of these carotenoids per day. CONCLUSIONS: In our population, a small number of fruits and vegetables can provide significant information on carotenoid intake (both annually and seasonally) to be used in the design of questionnaires for epidemiological studies, minimizing misclassification and errors. The marked seasonality of some products causes wide differences in the supply of, above all, beta-cryptoxanthin and lycopene.

Carotenoids↗

PubMed1995

Hyper-beta-carotenemia unrelated to diet: a case of brain tumor.

In addition to the provitamin A function of some carotenoids, many of them exhibit antioxidant activity. Epidemiological studies show that high serum levels and/or elevated intake of carotenoids have a protector effect against several chronic and degenerative diseases. We determined the levels and studied the behavior of the major carotenoids and retinol in serum of a brain tumor patient receiving standard (carotenoid-free) artificial enteral nutrition for eight months. After nearly two months on this diet, the retinol level was in the upper region of normal range and the beta-carotene concentration was unusually high. Analyses after several months on this diet showed a decrease in retinol, whereas the beta-carotene concentration had doubled (up to 203 micrograms/dl). Other carotenoids usually found in serum were present in very small amounts or not at all. We conclude that, although diet is an important factor in the presence and proportion of carotenoids in serum, the case we report here appears to indicate that other factors related to the development of certain diseases may be relevant determinants of changes in the carotenoid profile.

Adult↗

PubMed1994

Seasonal and sex-related variations in six serum carotenoids, retinol, and alpha-tocopherol.

We report the results of a study on the influence of season and sex on serum concentrations of six carotenoids, retinol, and alpha-tocopherol, as determined by reversed-phase HPLC. The subjects were 111 healthy individuals (54 females, 57 males); 18 additional subjects (10 females, 8 males) were assessed for within-subject longitudinal seasonal variations. Men presented significantly higher retinol concentrations (P = 0.002) and lower concentrations of provitamin A carotenoids--alpha carotene (P = 0.006), beta-carotene (P < 0.001), and beta-cryptoxanthin (P < 0.001)--than women. There were no significant differences between the sexes with respect to nonprovitamin A carotenoids (lutein, zeaxanthin, and lycopene) or alpha-tocopherol. Significant seasonal increments (P < 0.05) in serum concentrations of alpha-carotene and beta-carotene (in summer) and of beta-cryptoxanthin (in winter) were detected in both sexes; in males, lutein was higher in summer whereas in females it rose in spring. No sex-related or seasonal variations were observed in alpha-tocopherol, zeaxanthin, or lycopene. Serum concentrations of provitamin A carotenoids vary according to the individual's sex and season of the year.

Adult↗

PubMed1993

Carotenoids.

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Carotenoids↗

PubMed1986

Alpha-adrenoceptor involvement in catecholamine-induced hyperglycaemia in conscious fasted rabbits.

In conscious fasted rabbits an intravenous infusion of phenylephrine (20 micrograms kg-1 min-1) induced hyperglycaemia. The increase in blood glucose was accompanied by a modest increase in insulin secretion and a reduction of liver glycogen. Muscle glycogen and blood lactate levels were not altered by treatment with phenylephrine. Prazosin, 1 mg kg-1 s.c., partially attenuated phenylephrine-induced hyperglycaemia. Phenoxybenzamine infusion (16.6 micrograms kg-1 min-1) for 15 min suppressed the increase in blood glucose and the reduction in liver glycogen evoked by phenylephrine. This alpha-adrenoceptor blocker also clearly attenuated the blood glucose elevation observed on infusing adrenaline at 0.3 microgram kg-1 min-1. Blockade by phenoxybenzamine of phenylephrine- and adrenaline-induced hyperglycaemia was not accompanied by a significant increase in immunoreactive insulin plasma levels. Yohimbine infused at a rate of 20 micrograms kg-1 min-1, also completely blocked phenylephrine-induced hyperglycaemia. This suppressor effect was accompanied by a marked rebound in insulin secretion. It is concluded that in normal fasted rabbits stimulation of alpha-adrenoceptors induces hyperglycaemia. The increase in blood glucose depends mainly on liver glycogenolysis and inhibition of insulin secretion. Separate blockade of each component suffices to reduce alpha-adrenoceptor-mediated hyperglycaemia.

Adrenergic alpha-Antagonists↗

PubMedDate not supplied

Evaluation of retinol, alpha-tocopherol, and carotenoids in serum of men with cancer of the larynx before and after commercial enteral formula feeding.

BACKGROUND: Both epidemiologic and in vitro studies have indicated the inverse correlation between intake and/or blood concentrations of different carotenoids, retinol, and tocoferol with different chronic and degenerative disturbances (cancer, cardiovascular diseases, cataracts, aging). The purpose of this study was to determine the fat-soluble vitamin and carotenoid levels in men with recently diagnosed cancer of the larynx (n = 51) who had undergone total or partial laryngectomy and compare them with those of an age- and sex-matched control group (n = 51). In addition, the effects of commercial enteral formula feeding were assessed in a subgroup of these patients (n = 35). METHODS: A validated high-performance liquid chromatography method was used to determine the concentrations of six carotenoids (lutein, zeaxanthin, beta-cryptoxanthin, lycopene, alpha-carotene, and beta-carotene), retinol, and alpha-tocopherol in serum. Commercial, rather than blender prepared, enteral formulas were supplied to the patients as the only food source for an average period of 12 days. The statistical analysis was based on nonparametric methods (Mann-Whitney and Wilcoxon). RESULTS: The levels of all compounds analyzed were significantly lower in men with laryngeal cancer than in the control group. Retinol and tocopherol increased significantly after enteral formula feeding, although they continued to be significantly lower than those of the controls. The carotenoid levels decreased after enteral nutrition. CONCLUSIONS: The retinol and carotenoid concentrations should be monitored on a routine basis in these patients because of their relationship to this type of cancer. Moreover, it would be of interest to assess the effects of the addition of carotenoids to enteral formulas because they may offer protection from oxidative damage and potentiate the immune system.

Adult↗