Laura Leiva

Effects of vitamin D supplementation and exercise training on physical performance in Chilean vitamin D deficient elderly subjects.

The aim was to assess the effects of resistance training and vitamin D supplementation on physical performance of healthy elderly subjects. Ninety-six subjects, aged 70 years or more with 25 OH vitamin D levels of 16 ng/ml or less, were randomized to a resistance training or control group. Trained and control groups were further randomized to receive in a double blind fashion, vitamin D 400 IU plus 800 mg of calcium per day or calcium alone. Subjects were followed for nine months. Serum 25 OH vitamin D increased from 12.4+/-2.2 to 25.8+/-6.5 ng/ml among subjects supplemented with vitamin D. Trained subjects had significant improvements in quadriceps muscle strength, the short physical performance test and timed up and go. The latter improved more in trained subjects supplemented with vitamin D. At the end of the follow up, gait speed was higher among subjects supplemented with vitamin (whether trained or not) than in non-supplemented subjects (838+/-147 and 768+/-127 m/12 min, respectively, p=0.02). Romberg ratio was lower among supplemented controls than non-supplemented trained subjects (128+/-40% and 144+/-37%, respectively, p=0.05). In conclusion, vitamin D supplementation improved gait speed and body sway, and training improved muscle strength.

Colon cancer in Chile before and after the start of the flour fortification program with folic acid.

Background Folate depletion is associated with an increased risk of colorectal carcinogenesis. A temporal association between folic acid fortification of enriched cereal grains and an increase in the incidence of colorectal cancer in the USA and Canada has, however, been recently reported. Aim To compare the rates of hospital discharges owing to colon cancer in Chile before and after the start of the mandatory flour fortification program with 220 μg of synthetic folic acid/100 g of wheat flour. Methods Cancer and cardiovascular hospital discharge rates were compared using rate ratios between two study periods, 1992–1996, before folic acid fortification and 2001–2004, after the flour fortification with folic acid was established in the country. Standard errors of the log rate ratio to derive confidence intervals, and to test the null hypothesis of no difference, were calculated. Results The highest rate ratio between the two periods was for colon cancer in the group aged 45–64 years (rate ratio: 2.6, confidence interval: 99% 2.93–2.58) and in the 65–79 years (rate ratio: 2.9, confidence interval: 99% 3.25–2.86). Conclusion Our data provide new evidence that a folate fortification program could be associated with an additional risk of colon cancer.

Association between sarcopenia and mortality in healthy older people

Aim:  To evaluate the association between loss of fat‐free mass and mortality among older people.

Effects of enalapril or nifedipine on muscle strength or functional capacity in elderly subjects. A double blind trial.

Introduction. The inhibition of angiotensin-converting enzyme could be useful to avoid sarcopenia in the elderly. Materials and methods. We compared in a prospective double blind trial, the effects of treatment with enalapril or nifedipine on muscle performance in hypertensive elderly subjects. Patients were followed for nine months, and at baseline, 4.5 months and the end of follow-up, quadriceps and hand grip muscle strength, walking capacity, timed up and go and the short physical performance test were measured. Results. During follow-up, more subjects on nifedipine than on enalapril discontinued the medication due to side-effects. No differences in the evolution of muscle strength, walking capacity or functional measures were observed. At nine months, plasma angiotensin-converting enzyme activity decreased by 6.0±2.5 U/L among patients on enalapril and increased by 8.5±4.2 U/L (p<0.001) among patients on nifedipine. Conclusion. In this group of elderly subjects, enalapril was not superior to nifedipine with regard to the age-related decline of muscle performance.

Methylation status in healthy subjects with normal and high serum folate concentration.

OBJECTIVE We assessed the impact of high serum folate concentration on erythrocyte S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH) concentrations, SAM/SAH ratio, CpG methylation levels across the promoter region of the extracellular superoxide dismutase (ec-SOD) gene, and ec-SOD activity in healthy men. METHODS Serum folate levels were measured in 111 subjects who were categorized in quintiles according to their folate status. Subjects located at the lowest, middle, and upper quintiles were selected for assessment of SAM and SAH by high-performance liquid chromatography, C677T genotype of the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene, ec-SOD methylation of CpG sites in lymphocytes genomic DNA by bisulfate treatment, and ec-SOD activity by a chemical assay. RESULTS Sixteen subjects were in the lowest serum folate quintile (<23.6 nmol/L), 17 in the middle (>34-<42 nmol/L), and 14 in the highest (>45nmol/L). SAM concentration was higher in the upper than in the middle and lowest quintiles (5.57 +/- 1.58, 2.52 +/- 0.97, 2.29 +/- 1.2 micromol/L; P < 0.0001). SAH concentration was higher in the upper compared with the lowest quintile (0.76 +/- 0.24 versus 0.52 +/- 0.23 micromol/L, P < 0.001). There were no differences in the SAM/SAH ratio, ec-SOD activity, methylation status of CpG sites of the ec-SOD gene, and TMTHFR C677T genotype between groups. CONCLUSION Serum folate concentrations in the highest quintile among healthy humans are associated with increased erythrocyte SAM and SAH concentrations, but not with SAM/SAH ratio or with methylation levels of CpG sites across the promoter region of the ec-SOD gene. Further research is required to determine if these findings are beneficial or harmful.

Efecto del probiótico Saccharomyces boulardii en la prevención de la diarrea asociada con antibióticos en adultos ambulatorios en tratamiento con amoxicilina

Antibiotic-associated diarrhea is one of the mostcommon adverse effects of antimicrobials. Any antimicrobial can potentially produce diarrheabut beta-lactamics have a higher risk. Among these, amoxicillin is widely indicated inambulatory practice. One of the alternatives suggested to prevent antibiotic-associated diarrhea,is the use of the probiotic Saccharomyces boulardii.

Relationship of Adiposity and Insulin Resistance Mediated by Inflammation in a Group of Overweight and Obese Chilean Adolescents

The mild chronic inflammatory state associated with obesity may be an important link between adiposity and insulin resistance (IR). In a sample of 137 overweight and obese Chilean adolescents, we assessed associations between high-sensitivity C-reactive protein (hs-CRP), IR and adiposity; explored sex differences; and evaluated whether hs-CRP mediated the relationship between adiposity and IR. Positive relationships between hs-CRP, IR and 2 measures of adiposity were found. Hs-CRP was associated with waist circumference (WC) in boys and fat mass index (FMI) in girls. Using path analysis, we found that hs-CRP mediated the relationship between adiposity (WC and FMI) and the homeostatic model assessment of insulin resistance (HOMA-IR) (p < 0.05) in both sexes. Our novel finding is that inflammation statistically mediated the well described link between increased adiposity and IR.

Weight increase is associated with skeletal muscle immunostaining for advanced glycation end products, receptor for advanced glycation end products, and oxidation injury.

BACKGROUND Tissue accumulation of advanced glycation end products (AGEs) is associated with ageing, both in diabetics and nondiabetic subjects. AIM The purpose of this study was to assess immunostaining for AGEs, specifically carboxymethyl-lysine (CML) and receptor for AGEs (RAGE), in muscle tissue of healthy male subjects differing in age and weight stability. METHODOLOGY Muscle tissue was obtained during hernia surgery in middle-aged men reporting weight maintenance (WM, n = 10) or weight gain (WG, n = 7), and also in 4 elderly men. Tissue inmunostaining for CML and RAGE was performed. RESULTS Intensity of CML and RAGE staining were highly correlated (r = 0.84) and also significantly associated with weight change and age. Muscle AGEs accretion was statistically associated with muscle expression of oxidative injury (8-hydroxy-deoxyguanosine and 4-hydroxy-2-nonenal) and inflammatory markers (tumor necrosis factor-alpha). DISCUSSION The increase of skeletal muscle AGEs/RAGE and markers of inflammation and oxidative injury in association with weight gain and old age suggest a pathogenic role of AGEs in weight gain and in sarcopenia of aging.

High HOMA-IR, adjusted for puberty, relates to the metabolic syndrome in overweight and obese Chilean youths

Burrows RA, Leiva LB, Weisstaub G, Lera LM, Albala CB, Blanco E, Gahagan S. High HOMA‐IR, adjusted for puberty, relates to the metabolic syndrome in overweight and obese Chilean youths.

Assessment of sarcopenia: longitudinal versus cross sectional body composition data

Background and aims: An accurate diagnosis of sarcopenia is required. The aim of this study is to correlate the results of two methods to define sarcopenia using cross sectional body composition data, with actual loss of fat free mass. Methods: Healthy older subjects (926 females and 381 males aged 70 years or more) and healthy young adults (425 females and 151 males aged 20 to 40 years) were studied. Body composition was assessed by double beam X ray absorptiometry (DEXA). Among older subjects, a contemporary subsample of 148 females and 45 males had two or more measurements, separated by 4.8±1.5 years and loss of fat free mass per year was calculated. In the whole sample, total and appendicular lean body mass index were calculated as total or appendicular lean body mass/height. Using data from young people, sex specific t scores were obtained. In older subjects residuals were derived from a regression equation, using total or appendicular fat free mass as the dependent variable and height, fat free mass and age as independent variables. Results: The concordance between residuals and t scores to define sarcopenia was 68 and 72%, respectively. Among subjects with two or more measurements, men and women lost a mean of 521±454 and 221±399 g/year of fat free mass, respectively. The odds ratio of losing more than 822 g lean body mass/year among men or 514 g lean body mass/year among women was 2.63 and 2.64 for subjects classified in the two lowest quintiles of sarcopenia, using t scores or residuals, respectively. Conclusions: Cross sectional body composition data can predict loss of fat free mass among older people.