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Biomedical subjects

R Uauy

Publications and source records attributed to R Uauy.

At least 19 recordsLinked to original sources
PubMed2004

Copper overload affects copper and iron metabolism in Hep-G2 cells.

Divalent metal transporter #1 (DMT1) is responsible for intestinal nonheme Fe apical uptake. However, DMT1 appears to have an additional function in Cu transport in intestinal cells. Because the liver has an essential role in body Cu homeostasis, we examined the potential involvement of Cu in the regulation of DMT1 expression and activity in Hep-G2 cells. Cells exposed to 10 microM Cu exhibited a 22-fold increase in Cu content and a twofold decrease in Fe content compared with cells maintained in 0.4 microM Cu. (64)Cu uptake in Cu-deficient Hep-G2 cells showed a twofold decrease in K(m) compared with cells grown in 10 microM Cu. The decreased K(m) may represent an adaptive response to Cu deficiency. Cells treated with >50 microM Cu, showed an eightfold increase in cytosolic metallothionein. DMT1 protein decreased (35%), suggesting that intracellular Cu caused a reduction of DMT1 protein levels. Our data indicate that, as a result of Cu overload, Hep-G2 cells reduced their Fe content and their DMT1 protein levels. These findings strongly suggest a relationship between Cu and Fe homeostasis in Hep-G2 cells in which Cu accumulation downregulates DMT1 activity.

Cation Transport Proteins↗
PubMed2004

School-based obesity prevention in Chilean primary school children: methodology and evaluation of a controlled study.

OBJECTIVE: To assess the impact of a 6 months nutrition education and physical activity intervention on primary school children through changes in adiposity and physical fitness. DESIGN: Longitudinal school-based controlled evaluation study. SUBJECTS: Children from 1st to 8th grade, 2141 in intervention and 945 in control schools. INTERVENTION: Nutrition education for children and parents, 'healthier' kiosks, 90 min of additional physical activity (PA) weekly, behavioral PA program and active recess. MEASUREMENTS: Adiposity indices (BMI, BMI Z-score, triceps skinfold thickness (TSF), waist circumference and physical fitness (20 m shuttle run test and lower back flexibility). RESULTS: Positive effect on adiposity indices (except TSF) was observed in boys (P<0.001 for BMI Z), while both physical fitness parameters increased significantly in both boys (P<0.001 for each test) and girls (P<0.0001 for each test). A differential effect in BMI Z was observed according to baseline nutritional status. CONCLUSIONS: This intervention showed a robust effect on physical fitness in both genders and decreased adiposity only in boys.

Anthropometry↗
PubMed2002

Trends in overweight and obesity prevalence in Chilean children: comparison of three definitions.

OBJECTIVE: To compare trends in prevalence of overweight and obesity among Chilean children using three different criteria. METHODS: Descriptive cross-sectional school-based study to analyse these trends in 6-y-old boys and girls who entered first grade in 1987, 1990, 1993, 1996 and 2000. Gender-specific prevalence of overweight and obesity were determined with three criteria: weight for height (W-H) Z-scores compared to NCHS 1977; present reference used by the Ministry of Health; and body mass index (BMI) compared to the revised US CDC Growth Charts with cut-off values of P85-95 and P-95 and IOTF reference with cut-offs extrapolated from an adult BMI of 25 and 30. RESULTS: The prevalence of overweight determined by W-H (WHO) increased from 15% in 1987 to 20% in 2000 for boys and from 17.2 to 21.8% for girls. With BMI-CDC, the increase was from 13.2 to 19.2% for boys and 12 to 18.5% for girls. With BMI-IOTF, rates were very similar. Prevalence of obesity using W-H (WHO) increased from 6.5% in 1987 to 17% in 2000 for boys and from 7.8 to 18.6% for girls. Using BMI-CDC, the increase was from 5.1 to 14.7% for boys and from 4 to 15.8% for girls; using BMI-IOTF prevalence estimates were much lower. CONCLUSIONS: Obesity prevalence in children has increased over time, and trends are similar independent of criteria. The reference used to define prevalence is important since it provides different estimates. Policy makers should be aware that a spurious drop in prevalence may appear if the IOTF reference is compared to the other criteria.

Body Height↗
PubMed2001

Nausea threshold in apparently healthy individuals who drink fluids containing graded concentrations of copper.

Ingestion of drinking water with a high copper content may induce acute gastrointestinal effects, mainly nausea and vomiting, rarely diarrhea and abdominal pain. The objectives of this study were to define nausea threshold in apparently healthy adult volunteers who received graded concentrations of copper and to explore how individual thresholds were modified by delivering copper in an orange-flavored drink. Sixty-one healthy subjects received 200 mL of a copper-containing solution in purified water, at concentrations 0, 2, 4, 6, 8, 10, and 12 mg/L, as copper sulfate, in random order. Nausea threshold concentration for first response was established and then this threshold was confirmed. Subsequently, following the same design, subjects received the same copper concentrations (up to 12 mg/L), delivered in an orange-flavored drink, starting at the confirmed threshold concentration found in water. Mild nausea shortly after ingestion of copper-containing water was the most frequent finding (33/61 subjects), starting at 4 mg/L; vomiting was observed in 7 individuals, starting at 6 mg/L. The NOEL for copper in purified water was 2 and 4 mg/L for nausea and vomiting, respectively. When copper was provided as an orange-flavored drink, 11 subjects (18%) reported nausea, starting at 8 mg Cu/L, and no subjects vomited up to 12 mg Cu/L. It is concluded that after consumption of copper in purified water, the NOEL is 2 mg Cu/L and the LOAEL 4 mg Cu/L for nausea, while tolerable intake is between 2 and 4 mg Cu/L in water depending on whether apparent or confirmed nausea is used as the criterion to define critical effects.

Administration, Oral↗
PubMed2001

Essential fatty acids in visual and brain development.

Essential fatty acids are structural components of all tissues and are indispensable for cell membrane synthesis; the brain, retina and other neural tissues are particularly rich in long-chain polyunsaturated fatty acids (LC-PUFA). These fatty acids serve as specific precursors for eicosanoids, which regulate numerous cell and organ functions. Recent human studies support the essential nature of n-3 fatty acids in addition to the well-established role of n-6 essential fatty acids in humans, particularly in early life. The main findings are that light sensitivity of retinal rod photoreceptors is significantly reduced in newborns with n-3 fatty acid deficiency, and that docosahexaenoic acid (DHA) significantly enhances visual acuity maturation and cognitive functions. DHA is a conditionally essential nutrient for adequate neurodevelopment in humans. Comprehensive clinical studies have shown that dietary supplementation with marine oil or single-cell oil sources of LC-PUFA results in increased blood levels of DHA and arachidonic acid, as well as an associated improvement in visual function in formula-fed infants matching that of human breast-fed infants. The effect is mediated not only by the known effects on membrane biophysical properties, neurotransmitter content, and the corresponding electrophysiological correlates but also by a modulating gene expression of the developing retina and brain. Intracellular fatty acids or their metabolites regulate transcriptional activation of gene expression during adipocyte differentiation and retinal and nervous system development. Regulation of gene expression by LC-PUFA occurs at the transcriptional level and may be mediated by nuclear transcription factors activated by fatty acids. These nuclear receptors are part of the family of steroid hormone receptors. DHA also has significant effects on photoreceptor membranes and neurotransmitters involved in the signal transduction process; rhodopsin activation, rod and cone development, neuronal dendritic connectivity, and functional maturation of the central nervous system.

Brain↗
PubMed2001

Insulin homeostasis in the extremely low birth weight infant.

The need to improve the nutritional status of extremely low birth weight infants has resulted in a higher incidence of problems related to glucose intolerance. The inability of the newborn to inhibit gluconeogenesis in response to a glucose infusion has been postulated as an important determinant of the hyperglycemia observed in extremely low birth weight infants. The 2 proposed mechanisms to explain this finding include inappropriate secretion of insulin by the pancreas and decrease sensitivity of the liver to the gluco-regulatory effect of insulin. The capacity of extremely low birth weight infants to oxidize glucose at higher rates, and the positive effect that insulin may have in glucose utilization and tolerance, support the use of insulin in the prevention and treatment of hyperglycemia. Continuous infusion of insulin appears to be safe for the treatment of hyperglycemia, based on the available studies. However, the effectiveness of insulin treatment needs to be critically tested further before it can be implemented in routine clinical practice.

Diabetes Mellitus↗
PubMed2001

Determination of the taste threshold of copper in water.

Copper effects on human health represent a relevant issue in modern nutrition. One of the difficulties in assessing the early, acute effects of copper ingested via drinking water is that the taste of copper may influence the response and the capacity to taste copper in different waters is unknown. The purpose of the study was to determine the taste threshold of copper in different types of water, using soluble and insoluble salts (copper sulfate and copper chloride). Copper-containing solutions (range 1.0-8.0 mg/l Cu) were prepared in tap water, distilled deionized water and uncarbonated mineral water. Sixty-one healthy volunteers (17-50 years of age), with no previous training for sensory evaluation, participated in the study. A modified triangle test was used to define the taste threshold value. The threshold was defined as the lowest copper concentration detected by 50% of the subjects assessed. To evaluate the olfactory input in the threshold value obtained, 15 of 61 subjects underwent a second set of triangle tests with the nose open and clamped, using distilled water with copper sulfate at a concentration corresponding to the individual's threshold. The taste threshold in tap water was 2.6 mg/l Cu for both copper sulfate and copper chloride. The corresponding values for distilled deionized water were 2.4 and 2.5 mg/l Cu for copper sulfate and copper chloride, respectively. In uncarbonated mineral water the threshold values were slightly higher, 3.5 and 3.8 mg/l Cu for copper sulfate and for copper chloride, respectively, which are significantly higher than those observed in tap and distilled waters (P < 0.01, Kruskal-Wallis test). The taste threshold did not change significantly when the nose was clamped. In conclusion, the median values for copper taste threshold were low, ranging between 2.4 and 3.8 mg/l Cu, depending on the type of water.

Adolescent↗
PubMed2001

Obesity trends in Latin America: transiting from under- to overweight.

Latin America is undergoing a rapid demographic and nutritional transition. A recent WHO/PAHO survey on obesity in the region revealed an increasing trend in obesity as countries emerge from poverty, especially in urban areas. In contrast, in middle income countries, obesity tends to decline as income increases; this is especially so in women. Dietary changes and increasing inactivity are considered the crucial contributory factors that explain this rise. The end result is a progressive rise in overweight and obesity, especially in low income groups who improve their income and buy high fat/high carbohydrate energy-dense foods. Intake of these foods increases to the detriment of grains, fruits and vegetables. Most aboriginal populations of the Americas have changed their diet and physical activity patterns to fit an industrialized country model. They now derive most of their diet from Western foods and live sedentary and physically inactive lives. Under these circumstances they develop high rates of obesity, insulin resistance and type 2 diabetes. Supplementary feeding programs are common in the region; the number of beneficiaries significantly exceeds the malnourished. Weight-for-age definition of undernutrition without assessment of length will overestimate the dimension of malnutrition and neglect the identification of stunted overweight children. Providing food to low income stunted populations may be beneficial for some, although it may be detrimental for others, inducing obesity especially in urban areas. Defining the right combination of foods/nutrients, education and lifestyle interventions that are required to optimize nutrition and health is a present imperative.

Adolescent↗
PubMed2001

Nutrition transition in Latin America: the case of Chile.

The nutritional situation of Latin America is changing rapidly from one characterized by underweight and stunting to one where chronic diseases such as cancer, cardiovascular disease, and type 2 diabetes are increasingly prevalent. In Chile, under-nutrition has virtually disappeared, but rising obesity rates and risk factors for chronic diseases indicate the need to modify existing programs and emphasize prevention of diet-related chronic diseases.

Cause of Death↗
PubMed2001

Gastrointestinal effects associated with soluble and insoluble copper in drinking water.

The aim of this study was to determine whether total copper or soluble copper concentration is associated with gastrointestinal signs and symptoms. Forty-five healthy adult women (18-55 years of age), living in Santiago, Chile, ingested tap water with 5 mg/L of copper containing different ratios of soluble copper (copper sulfate) and insoluble copper (copper oxide) over a 9-week period. Three randomized sequences of the different copper ratios (0:5, 1:4, 2:3, 3:2, and 5:0 mg/L) were followed. Subjects recorded their water consumption and gastrointestinal symptoms daily on a special form. Mean water consumption was similar among groups. Serum copper levels, ceruloplasmin, and activities of liver enzymes were within normal limits. No differences were detected between the means of biochemical parameters at the beginning and at the end of the study. Twenty subjects presented gastrointestinal disturbances at least once during the study, 9 suffered diarrhea (with or without abdominal pain and vomiting), and the other 11 subjects reported abdominal pain, nausea, or vomiting. No differences were found in incidence of abdominal pain, nausea, vomiting, and diarrhea regardless of the ratio of copper sulfate to copper oxide. In conclusion, both copper sulfate (a soluble compound) and copper oxide (an insoluble compound) have comparable effects on the induction of gastrointestinal manifestations, implying that similar levels of ionic copper were present in the stomach.

Abdominal Pain↗
PubMed2001

Long chain polyunsaturated fatty acids (LC-PUFA) and perinatal development.

UNLABELLED: This paper reports on the conclusions of a workshop on the role of long chain polyunsaturated fatty acids (LC-PUFA) in maternal and child health. The attending investigators involved in the majority of randomized trials examining LC-PUFA status and functional outcomes summarize the current knowledge in the field and make recommendations for dietary practice. Only studies published in full or in abstract form were used as our working knowledge base. CONCLUSIONS: For healthy infants we recommend and strongly support breastfeeding as the preferred method of feeding, which supplies preformed LC-PUFA. Infant formulas for term infants should contain at least 0.2% of total fatty acids as docosahexaenoic acid (DHA) and 0.35% as arachidonic acid (AA). Since preterm infants are born with much less total body DHA and AA, we suggest that preterm infant formulas should include at least 0.35% DHA and 0.4% AA. Higher levels might confer additional benefits and should be further investigated because optimal dietary intakes for term and preterm infants remain to be defined. For pregnant and lactating women we consider it premature to recommend specific LC-PUFA intakes. However, it seems prudent for pregnant and lactating women to include some food sources of DHA in their diet in view of their assumed increase in LC-PUFA demand and the relationship between maternal and foetal DHA status.

Animals↗
PubMed2001

[Food based approaches to improve vitamin and mineral nutrition adequacy].

This paper, using the nutrient density concept and the development of Food-Based Dietary Guidelines (FBDG), explores the nutritional adequacy of food patterns based on the main staples around the world--maize, wheat, rice and potato. The nutritional adequacy of the vitamins A, C, folates and the minerals iron, zinc and calcium in diets composed by these staples is analyzed. Projected diets modified by the addition of foods high in vitamins and minerals, based on food table composition information, are analyzed for changes in nutritional adequacy, in order to cover the nutritional requirements of all family members. This theoretical exercise shows that diets diversified by the addition of relatively small quantities (27-70 g) of foods like fruits, vegetables, legumes and meat improve substantially the nutritional adequacy of the vitamins A, C, folates, iron and zinc. In the case of calcium, the addition of a dairy source becomes essential. From the practical point of view, the implementation of the food based approach requires a national effort in order to support the production of nutrient rich foods and to promote consciousness of nutrient bioavailability, so that people may obtain all nutrient potential from foods. Simultaneously, the need of fortification programs at the national level is recognized. This is the case for critical nutrients, where requirements might be above the potential in available foods. A similar situation occurs in the case of vulnerable groups like pregnant women and infants, who need supplementation to ensure nutritional adequacy of their diets. In conclusion, the use of FBDG is a good alternative for improving the nutritional adequacy of diets based predominantly on staple foods. However, food fortification and supplementation programs directed to vulnerable groups are necessary and complementary practices to the FBDG implementation.

Ascorbic Acid↗