Biomedical subjects

Cristina Lasheras

Publications and source records attributed to Cristina Lasheras.

8 recordsLinked to original sources

PubMed2006

Food intake and serum selenium concentration in elderly people.

BACKGROUND/AIMS: It is becoming apparent that the essential trace element selenium plays a critical role in the maintenance of optimal health status. The objective of this study was to identify the food groups that most contributed to selenium intake and its serum levels in elderly people. METHODS: Dietary intake was assessed in 205 institutionalized elderly by means of a 1-year food frequency questionnaire (FFQ). Intake of macronutrients and minerals of the diet were estimated. Selenium was determined in serum and analyzed by graphite-furnace atomic absorption spectrometry. RESULTS: Selenium intake and serum concentration were both within the normal range. The major contributors to selenium intake were cereals and bakery, fish and shellfish, meat and meat products and dairy products. All of them except cereals were also associated to serum selenium. Intake of animal protein, but not the vegetable one, contributed to serum selenium. CONCLUSION: An adequate intake of fish and meat would be of importance to improve selenium status and health principally in elderly people who are at high risk of mineral deficiency.

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PubMed2006

Lipid peroxidation, antioxidant status and survival in institutionalised elderly: a five-year longitudinal study.

Oxidative stress has been related to ageing and risk of death. To determine whether oxidative status was associated with all-cause risk of death we carried out a prospective study in 154 non-smoking Spanish elderly without major illness. Baseline glutathione peroxidase (GPx) and superoxide dismutase (SOD) were analysed in plasma and erythrocytes. alpha-tocopherol, beta-carotene, lycopene and retinol were determined in serum samples and malondialdehyde (MDA), as a lipid peroxidation marker, in plasma. Mean survival time was 4.3 years. A total of 31 death cases (20.1%) occurred during the follow-up. Plasma-MDA predicted mortality independently of all other variables, while erythrocyte-SOD (e-SOD), beta-carotene and alpha-tocopherol were positively associated with survival. alpha-tocopherol and MDA were revealed as independent predictors in a joint survival model, being the group with low MDA and high alpha-tocopherol that with the lowest mortality. In conclusion, a higher risk of death was associated with increased lipid peroxidation and lower antioxidant defenses.

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PubMed2004

Folate and cobalamin synergistically decrease the risk of high plasma homocysteine in a nonsupplemented elderly institutionalized population.

OBJECTIVE: Total plasma homocysteine (tHcy) has been associated with an increased risk of cardiovascular disease in the general population and elderly subjects are at high risk of elevated homocysteine because of an impaired vitamin status. The aim of the present study was to determine the independent and interactive association of adequate folate and cobalamin (intake and serum levels) with tHcy in elderly subjects who were not taking vitamin supplementation. DESIGN AND METHODS: Cross-sectional analysis of a sample of 140 elderly recruited from seven nursing homes in Asturias (Northern Spain). Dietary intake was assessed by a food frequency questionnaire, and serum folate, cobalamin, and tHcy were determined in fasting blood samples. RESULTS: Mean tHcy concentration was 13.3 micromol/L (upper quartile of tHcy >16.0 micromol/L) and was inversely correlated with serum folate. Subjects with an adequate intake or serum levels of both folate and B12 were at a reduced risk of being in the highest quartile of tHcy. In both cases, the reduction of high tHcy (upper quartile) risk was found to be greater than expected when subjects with high levels of both vitamins were considered together. CONCLUSIONS: Adequate folate and cobalamin (both intake and serum levels) act synergistically to decrease the risk of high total plasma homocysteine levels in this elderly population.

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PubMed2004

No evidence for oxidative stress as a mechanism of action of hyperhomocysteinemia in humans.

Oxidative stress has been suggested as one of the physiopathologic conditions underlying the association of total plasma homocysteine (p-tHcy) with cardiovascular disease (CVD), but this hypothesis has not been validated in human epidemiological studies. We measured plasma and erythrocyte antioxidant enzymes glutathione peroxidase (GPx) and superoxide dismutase (SOD), along with serum lipid-soluble antioxidants alpha-tocopherol, beta-carotene, lycopene and retinol, in a sample of 123 healthy elderly subjects (54 men, 69 women). Plasma malondialdehyde (p-MDA) was determined as a marker of lipid peroxidation, and p-tHcy was quantified by HPLC. No significant differences were found for p-MDA, GPx or SOD activities or serum antioxidant concentrations, in subjects with elevated p-tHcy (> or =15 micromol/l) as compared to those with lower plasma homocysteine. Hyperhomocysteinemia did not lead to increased risk of having the highest p-MDA values, in either sex. We found no evidence that p-tHcy was associated with lipid peroxidation in this elderly human sample. Our results do not support the view that hyperhomocysteinemia would induce an adaptive response of antioxidant systems, either. More epidemiologic and clinical research is needed to clarify whether homocysteine promotes atherosclerosis by means of an oxidative stress mechanism.

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PubMed2004

Serum selenium is associated with plasma homocysteine concentrations in elderly humans.

Low selenium levels in humans have been associated with several pathologies; however, an earlier animal investigation found a direct association between Se intake and total plasma homocysteine (tHcy) concentrations. To date, the importance of serum selenium levels in association with tHcy in humans has not been determined. We evaluated the cross-sectional association of blood selenium concentrations with plasma tHcy and other determinants of this cardiovascular disease risk factor. We estimated protein intake and measured the blood status of selenium, tHcy, and several other related factors in serum such as folate, vitamin B-12, and creatinine. Serum selenium was inversely associated with tHcy, explaining 5.8% of tHcy variance with respect to 2.2% accounted for by serum folate. Furthermore, there was a 63% decreased risk of higher tHcy concentrations (>14 micro mol/L) for subjects with serum selenium in the highest tertile (P = 0.013). We also found an inverse association of protein intake with tHcy in men (beta = -0.144; P = 0.036), which disappeared after controlling for serum Se concentrations (beta = -0.055; P = 0.003). In conclusion, selenium should be considered as a potential factor to lower tHcy. In addition, the described association between protein intake and homocysteine levels could be mediated by this trace element.

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PubMed2003

Food habits are associated with lipid peroxidation in an elderly population.

OBJECTIVE: The purpose of this study was to assess the association between dietary intake and lipid peroxidation. DESIGN: Cross-sectional population analysis from an ongoing prospective study. Malondialdehyde (MDA) was measured as a marker of lipid peroxidation. Diet was assessed through direct observation and food frequency questionnaire. SUBJECTS: Participants with no missing data were 162 nonsmoking elderly individuals residing in 7 institutions across Asturias (Spain). STATISTICAL ANALYSES PERFORMED: Comparisons of adjusted group means by tertiles of plasma MDA were made by analysis of variance. Stepwise regression analysis was done using MDA as a dependent variable and food intake as an independent variable. Food intakes were categorized into quartiles and logistic regression was applied to calculate the odds ratio for being in the highest tertile of plasma MDA. RESULTS: Consumption of potatoes had an independent direct effect and accounted for a sizeable proportion of the variation in plasma MDA levels (18%, P<.001). In addition to potatoes, other foods that had an apparently independent effect on plasma MDA were eggs, cooked vegetables, and red wine (R(2)=0.028, 0.023 and 0.018, respectively). In this study, dietary factors accounted for 25% of the variation in plasma MDA levels. CONCLUSION: Identifying nutritional determinants of oxidative stress is important because of its negative health effect. Consumption of cooked vegetables and moderate intake of wine has been shown to be appropriate for reducing the risk of oxidative damage. On the contrary, caution must be used with the intake of potatoes because we have found a positive association with MDA levels. Further studies are required to investigate the mechanism(s) of this association and whether it is related to the preparation method or to the potato itself.

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PubMed2003

Plasma iron is associated with lipid peroxidation in an elderly population.

Epidemiological evidence has raised concern that a moderate elevation in body iron stores may increase oxidative stress and risk of heart disease. We examined the cross-sectional association between plasma iron and factors that could affect its levels (antioxidant enzymes, diet), with the concentration of plasma malondialdehyde (MDA) as a marker of lipid peroxidation. Participants were 162 non-smoking institutionalised elderly. Our results show that those in the highest tertile of plasma iron were at least twice as likely to have higher plasma MDA levels. Among the factors affecting plasma iron levels, we found that the upper tertile of erythrocyte-superoxide dismutase (E-SOD) was inversely associated with higher plasma iron, and potato intake explained a sizeable proportion of the variation in plasma iron levels. In addition to potatoes, eggs, wine, fruit in men and green vegetables in women showed a positive association with plasma iron levels. Only potatoes in both sexes, wine in men and eggs in women had an independent effect on plasma MDA. Potatoes, wine, plasma lycopene and plasma iron accounted for 43% of the variability in plasma MDA for males, and E-SOD, potatoes, eggs, plasma lycopene and plasma iron explained 45% for women. A longitudinal study should confirm, whether these MDA levels are related to morbidity and mortality.

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PubMed2002

Independent and interactive association of blood antioxidants and oxidative damage in elderly people.

Oxidative stress is recognized as one of the major contributors to the increased risk of several diseases. Many recent population studies have established a close link between antioxidant defense and lowered risk of morbidity and mortality from cancer and heart disease, but little is known about the cooperative interactions of antioxidants. We examined the cross-sectional independent and interactive association of serum lipid-soluble antioxidant levels and free radical scavenging enzymes to serum malondialdehyde (MDA) levels, as a marker of oxidative damage. The participants were 160 nonsmoker institutionalized elderly. Upper tertile values of erythrocyte-superoxide-dismutase (E-SOD) constituted the strongest-associated single compound with a 74% decreased risk of high MDA. Upper tertiles of carotenoids and alpha-tocopherol independently showed a similar lowering of risk of about 57%. The highest tertiles of lycopene and either beta-carotene or alpha-tocopherol simultaneously reveal a higher decreased risk for oxidative damage (74 and 71%, respectively), very similar to those in the upper tertiles of all these three vitamins (75%). This study represents one of the few attempts to date to understand the interactive effect between antioxidants and suggests that lipid-soluble antioxidants act not individually, but rather cooperatively with each other. The efficacy of this interaction is more effective when lycopene is present.

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