Veronica Lopez-Teros

Vitamin A-Fortified Milk Increases Total Body Vitamin A Stores in Mexican Preschoolers

Vitamin A (VA) deficiency (VAD) continues to be a major nutritional problem in developing countries, including Central America. In Mexico, milk is a well-accepted vehicle for the administration of micronutrients, including VA, to preschoolers. Thus, we conducted a randomized, controlled, clinical trial to investigate the efficacy of daily consumption of 250 mL of VA-fortified milk (which provided 196 retinol equivalents/d) for 3 mo on VA stores in mildly to moderately VAD (serum retinol concentration 0.35-0.7 μmol/L) preschoolers who were not enrolled in a food assistance program. Twenty-seven mildly to moderately VAD children were randomly assigned based on screening measurements to either the intervention (n = 14) or control group (n = 13) (children in the control group did not receive placebo). All children in the control group and 79% (n = 11) of the children in the intervention group completed the study. The total body VA (TBVA) pool size was estimated using the deuterated retinol dilution technique before and after the intervention. After 3 mo, median changes in the serum retinol concentration for the intervention and control groups were 0.13 and -0.21 μmol/L, respectively (P = 0.009). Median changes in the TBVA stores were 0.06 and 0.01 mmol, respectively (P = 0.006) and estimated median changes in the liver VA concentration were 0.09 and 0.01 μmol/g, respectively (P = 0.002). The VA-fortified milk was well accepted among preschoolers and significantly increased TBVA stores, liver VA stores, and serum retinol concentration, indicating that it may be an effective means to ameliorate VAD in young Mexican children.

Giardia lamblia Infection and Its Implications for Vitamin A Liver Stores in School Children

Background: Vitamin A deficiency (VAD) is a nutritional problem affecting the health of people in developing countries because VAD compromises innate and adaptive immunity, increasing a person’s predisposition toward infectious diseases. In addition, a high prevalence of infectious diseases continues to be a problem in developing countries, including Giardia lamblia. G. lamblia may be related to VAD because of its ability to change the intestinal architecture, thereby compromising the absorption of vitamin A. The aim of this study was to evaluate the effect of giardiasis on serum retinol levels and vitamin A liver stores in school children. Methods: Thirty Giardia-infected school children participated in this study. Vitamin A liver stores were evaluated with the modified relative dose response (MRDR) technique, and antiparasitic treatment was administered. In addition, anthropometric and dietary data were collected. Results: According to anthropometric indicators (age-appropriate Z scores for weight, height and body mass index) and daily vitamin A intake, the children had a normal nutritional status. Although the mean serum retinol levels did not change significantly after treatment for Giardia (p > 0.05), the MRDR values showed significant improvement (p < 0.002). Conclusion: Giardiasis not only compromises the vitamin A status through intestinal malabsorption, it also causes profound mobilization of liver retinol stores.

Current Capabilities and Limitations of Stable Isotope Techniques and Applied Mathematical Equations in Determining Whole-Body Vitamin A Status.

Background: Retinol isotope dilution (RID) methodology provides a quantitative estimate of total body vitamin A (VA) stores and is the best method currently available for assessing VA status in adults and children. The methodology has also been used to test the efficacy of VA interventions in a number of low-income countries. Infections, micronutrient deficiencies (eg, iron and zinc), liver disease, physiological age, pregnancy, and lactation are known or hypothesized to influence the accuracy of estimating total body VA stores using the isotope dilution technique. Objective: Our objectives were to review the strengths and limitations of RID methods, to discuss what is known about the impact of various factors on results, and to summarize contributions of model-based compartmental analysis to assessing VA status. Methods: Relevant published literature is reviewed and discussed. Results: Various equations and compartmental modeling have been used to estimate the total body VA stores using stable isotopes, including a newer 3-day equation that provides an estimate of total body VA stores in healthy adults. At present, there is insufficient information on absorption of the isotope tracer, and there is a need to further investigate how various factors impact the application of RID techniques in field studies. Conclusions: Isotope dilution methodology can provide useful estimates of total body VA stores in apparently healthy populations under controlled study conditions. However, more research is needed to determine whether the method is suitable for use in settings where there is a high prevalence of infection, iron deficiency, and/or liver disease.

‘Dose-to-Mother’ Deuterium Oxide Dilution Technique: An Accurate Strategy to Measure Vitamin A Intake in Breastfed Infants

In Mexico, infants (0–2 years old) show the highest prevalence of vitamin A deficiency (VAD), measured by serum retinol concentrations. Thus, we consider that low vitamin A (VA) intake through breast milk (BM) combined with poor weaning practices are the main factors that contribute to VAD in this group. We combined the assessment of VA status in lactating women using BM retinol and a stable isotope ‘dose-to-mother’ technique to measure BM production in women from urban and agricultural areas. Infants’ mean BM intake was 758 ± 185 mL, and no difference was observed between both areas (p = 0.067). Mean BM retinol concentration was 1.09 μmol/L, which was significantly lower for the agricultural area (p = 0.028). Based on BM retinol concentration, 57% of women were VAD; although this prevalence fell to 16% when based on fat content. Regardless of the VA biomarker used here, infants from the urban and agricultural areas cover only 66% and 49% of their dietary adequate intake from BM, respectively (p = 0.054). Our data indicate that VAD is still a public health concern in Mexico. Adopting both methods to assess VA transfer from the mother to the breastfed child offers an innovative approach towards the nutritional assessment of vulnerable groups.

Selected Physiological Effects of a Garcinia Gummi-Gutta Extract in Rats Fed with Different Hypercaloric Diets

Garcinia gummi-gutta (GGG) rind extract is effective for reducing appetite, body weight and adiposity of obese rodents fed high-fat (HF), high-sugar (HS) or high fat/sugar (HFS)-based diets, but these effects have not been simultaneously evaluated. Thirty obese (~425 g) male Wistar rats were fed for eleven weeks with six hypercaloric diets (4.1 kcal/g; five rats/diet) non-supplemented (HF, HS, HFS), or supplemented (HF+, HS+, HFS+) with GGG extract (5.9%), while rats from the control group (375 g) were fed a normocaloric diet (3.5 kcal/g). Body weight, dietary intake, body fat distribution, and histological and biochemical parameters were recorded. Compared to control rats, non-supplemented and supplemented groups consumed significantly less food (14.3% and 24.6% (−4.3 g/day), respectively) (p < 0.05). Weight loss was greater in the HF+ group (35–52 g), which consumed 1.9 times less food than the HS+ or HFS+ fed groups. The HF and HFS groups showed 40% less plasma triacylglycerides and lower glucose levels compared to the HF+. GGG-supplemented diets were associated with lower ketonuria. The HF+ diet was associated with the best anti-adiposity effect (as measured with the dual X-ray absorptiometry (DXA) and Soxhlet methods). The severity of hepatocyte lipidosis was HF > control > HF+, and no signs of toxicity in the testes were observed. The results indicate that GGG is more effective when co-administered with HF diets in obese rats.