View clinical trials related to Vitamin A Status.
Filter by:The goal of this study is to assess whether 3-5 years-old children who have Vitamin A intakes above the tolerable upper intake level (UL=900 ug per day) have higher total body Vitamin A stores and biomarkers of excessive vitamin A status, compared to children with Normal Vitamin A intakes (250-600 ug per day).
Vitamin A deficiency (VAD) remains a public health problem that occurs in children and women. WHO estimates that 190 million preschool age children (under five years of age) and 19.1 million pregnant women have inadequate concentrations of retinol . VAD may increase risk of morbidity and mortality during childhood, pregnancy and postpartum period . In developing countries, vitamin A status in lactating women is not optimal. Even in the United States, vitamin A status of low income pregnant women is marginal. Therefore, women of reproductive age are at risk of vitamin A depletion which compromises the vitamin A status of breastfed infants. Vitamin A is transferred to milk from both retinol binding protein bound and chylomicron associated vitamin A carriers. Because of teratogenicity of vitamin A, the transfer of vitamin A from pregnant mother to the fetus is carefully controlled. This results in all infants born with very low stores of vitamin A . Therefore human milk is still the best vitamin A source for infants. The concentration of vitamin A in breast milk is highest in the first 21 days postpartum (colostrum in the first 4-6 days and transitional milk in the next 7-21 days). Breast milk vitamin A concentrations and an infant's vitamin A status are based on maternal dietary intake. Breast milk retinol concentrations are a useful tool and a unique indicator for lactating women and represents extrapolations of vitamin A status of breastfed infant. In high risk vitamin A deficiency areas, prior recommendation for lactating women was to give two doses of 200,000 IU vitamin A within 6 weeks post-delivery . However, the lack of impact evidence of this regimen led to the WHO's withdrawal of such recommendation as a public health policy . Food-based intervention has been regarded as a sustainable approach to improve population vitamin A status. Most recently, vitamin A-depleted sows fed high-provitamin A carotenoid maize resulted in significant increase in liver stores in nursing piglets and significant higher milk retinol concentrations than sows fed white maize that given a high-dose vitamin A supplement . Previous efforts to fortify staples or common vehicles with vitamin A offer promising solution to prevention of vitamin A deficiency in vulnerable population . Food fortified with vitamin A has potentials to improve women's vitamin A status and to increase the vitamin A concentrations of breast milk . Rice as the most important staple food in Thailand, represents the culture of consumption and lifestyle of Thai people . Recent study in Thai school children fed with extruded rice grains fortified with zinc, iron and vitamin A every weekday for 2 months, significantly increased liver stores of vitamin A, as assessed with a stable isotope technique . Likewise, fortification of rice with vitamin A may also benefit mothers during lactation. The outcomes of this study will be useful to guide the promotion of food-based strategies to improve vitamin A status of mother and infant during lactation.
The goal of this study is to assess whether children 12-18 months of age who are exposed to multiple large-scale vitamin A programs, and who are likely to have vitamin A intakes above the tolerable upper intake level (UL), have higher total body vitamin A stores and biomarkers of excessive vitamin A status, compared to children 12-18 months of age who have adequate vitamin A intake.
The combination of poverty-related infectious and lifestyle-related non-communicable diseases, both driven by malnutrition, causes a high burden for South Africa. Healthy and nutritious diets for populations depend on availability and accessibility of a variety of plant and animal foods, within a context that promotes and supports healthy behaviour. Food based strategies, such as supplementation, food fortification, and diversification of crops, are used to achieve optimal dietary requirements to combat malnutrition, including micronutrient deficiencies. A more sustainable food based strategy is the (promotion of) use of indigenous and traditional foods, such as African Leafy Vegetables (ALVs). Unfortunately, several studies from all over Africa have shown that there is a shift from traditional diets as result of the preparing techniques and the absence of women in homes. Furthermore, indigenous and traditional foods are considered as "poor people's food". Against this background, a joint project between South Africa, Kenya and Benin is designed to fill the gaps in knowledge in these countries regarding the availability, acceptability and consumption and evidenced based benefits of foods from local biodiversity. The main aim of the study in South Africa is to provide empirical evidence of how the role of biodiversity can be translated into improved health status in contemporary poor rural and urban communities in the North West Province of South Africa. In order to achieve this it is important to gain knowledge on the possibility of using ALVs as a strategy to alleviate micronutrient deficiencies. Therefore an intervention study to determine the effect of selected ALV on the nutritional status (including zinc, iron, and vitamin A status) of school children (grade R-4) residing in contemporary poor rural community in the North West Province, South Africa has been designed.
The purpose of this pilot study is to determine whether breast milk retinol concentration increases in response to daily supplementation with small amounts of vitamin A (~600 ug RAE/d), as either a b-carotene or retinyl palmitate, 6 d/week for 3 weeks. A secondary purpose is to evaluate sampling methods for collecting breast milk samples in a community setting. The results of this pilot study will allow us to determine whether milk retinol is a useful indicator for evaluating the impact of food-based interventions on the vitamin A status of lactating women.
The study hypothesis is that high ß-C yellow maize can provide vitamin A efficiently. - list item one ß-C in yellow maize The study will use stable isotope labeled high ß-C yellow maize and vitamin A in a well-nourished population by utilizing stable isotope dilution techniques. In this project, deuterium labeled vitamin A that is derived from the labeled ß-C yellow maize will be traced after being eaten by a human subject. Eight men (> 40 years and < 70 y) who are healthy, non-smoking,body weight within 20% of standard weight for height (Metropolitan) and not having taken vitamin A or ß-C supplements within the last month will be recruited as volunteers. This study will last for 50 days during which at day 1, cooked labeled yellow maize paste (porridge) equal to a total of ~ 2 bowls cooked yellow maize (from 100 - 200 g dry weight) containing ~ 1 mg ß-C will be taken by each volunteer. On day 8, a labeled vitamin A (1 mg of 13C retinyl acetate) in oil dose will be used in evaluation of liver storage of vitamin A. Forty six blood samples (460 cc) will be taken during the study which will be analyzed for serum carotenoids and retinoids using HPLC and mass spectrometry techniques. The serum concentration and isotope ratio of ß-C and retinol will be determined. Serum enrichment curve following each oral dose will be studied. The area under the curve (AUC) of retinol-d4 and labeled retinol from the reference dose in serum samples will be determined and compared. The equivalence of a high ß-C corn meal to vitamin A will be calculated based on the isotope reference method to determine the efficiency of corn ß-C to provide vitamin A.