17 Clinical Trials for Various Conditions
Fifteen female study participants will be enrolled in a randomized crossover study to measure fractional and total zinc and iron absorption from four common bean (Phaseolus vulgaris) varieties with varying phytate and polyphenolic contents. Phytate, the storage form of phosphorus in plants, and polyphenols, which contribute to the varied colors of common beans, are natural components of the beans and can reduce zinc and iron bioavailability from these foods.
The FeMicrobiome study will evaluate gut microbiome features and their relationships with dietary iron absorption in healthy adults. The investigators hypothesize that (1) the gut microbiota can be shaped by the heme and non-heme Fe content of the diet and that (2) this will influence individual variation in dietary Fe absorption.
This study aims to; 1) investigate population differences in iron absorption between East Asians and Northern Europeans; 2) assess population differences in hormonal and biochemical determinants of Fe absorption between East Asians and Northern Europeans; and 3) to investigate genetic contributions to Fe absorption, Fe status and Fe regulatory hormones between East Asians and Northern Europeans.
Iron is a nutritionally essential mineral required for optimal physical and cognitive performance. Endurance exercise often leads to declines in iron status; however, the reason for the decline is not known. The primary objective of the proposed study is to determine the effects of an acute bout of strenuous endurance exercise on iron absorption and status and markers of inflammation in human volunteers. The investigators hypothesize that an acute bout of strenuous endurance exercise, compared to rest, will reduce iron absorption, resulting in diminished iron status, and that reduced iron absorption will be negatively associated with markers of inflammation. A secondary objective is to monitor iron status throughout a season of competition.
Ferrous sulfate is rapidly absorbed and the bolus of iron enters blood rather quickly possibly leading to higher concentrations of non-transferrin bound iron which induces oxidative stress. The objective of this study was to determine how quickly iron enters into blood stream from the iron-enriched Asperigillus oryzae (AspironTM, ASP) in contrast to ferrous sulfate. Seventeen healthy, female subjects (18-35 y) were randomized, double blind, cross-over experimental design with three treatments: 10 mg iron as FeSO4 and ASP as well as 20 mg iron as ASP.
The two specific aims of this study are: 1) to assess the impact of a genetic variant on iron status; 2) to assess the impact of a genetic variant on non-heme absorption among Asian women. The investigators hypothesize that the genetic variant could enhance iron status and iron absorption in Asian women.
Few areas are more controversial in pediatric nutrition than the role of a vegetarian diet for children. Advocates make strong health claims whereas others have expressed safety concerns, especially regarding iron nutrition. The frequency of vegetarianism among children is said to be rapidly increasing although clear data are not available. Surveys of children in the US age 8 to 18 reported in the media find that about 3-5% of children are lacto-ovo vegetarian, with some fish or chicken products in the diet. This is a substantial proportion that is very likely to increase over the next few years with essentially no nutrient metabolism data related to this population. One of the principal concerns with a lacto-ovo vegetarian diet, as preferred by many children, is the lack of heme iron in the diet. A key question that can be evaluated in children is whether iron status is in fact affected by a lacto-ovo vegetarian diet. According to the American Academy of Pediatrics (AAP Pediatric Nutrition Handbook, 6th Edition, 2008), vegetarian diets can provide appropriate nutrition for children. Depending on the level of dietary restriction, fortified foods or supplements may be necessary during different life stages. In addition, strict vegetarian children may have slightly higher protein needs compared to non-vegetarian children due to decreased protein digestibility in certain plants. The AAP further recommends that children 4-8 years old consume a minimum of five servings per day of beans/nuts/seeds/eggs and six servings per day of calcium-rich foods. To evaluate this issue, the investigators will use a stable isotope method to directly assess iron status. It is increasingly recognized that the ability to absorb iron when given with vitamin C is a highly accurate measurement of iron status and may be a true gold standard in this regard. In this planned study, investigators will be able to assess both reference dose iron absorption and standard biochemical markers of iron status in a group of lacto-ovo vegetarians and compare them with age- and gender-matched children on a non-vegetarian diet. These data can be important in determining if iron status is decreased in lacto-ovo vegetarians and will serve as a basis for future interventions and evaluations if a difference is found.
Iron deficiency is a common health problem worldwide. Ferrous fumarate (a form of iron) is often added to foods in an effort to prevent iron deficiency. Vitamin C can improve the amount of iron that the body absorbs, therefore it is often added to foods too. However, we don't know if vitamin C really increases the absorption of iron from ferrous fumarate. This study will measure the iron absorption in children from a meal containing some ferrous fumarate with and without vitamin C. The study will include 4 visits to the Children's Nutrition Research Center in Houston, TX.
This study will measure nonheme iron absorption from each of the 7 daily MyPyramid menus. Such measurements will confirm whether modifications are needed to meet dietary iron recommendations and will provide data useful for validation algorithms to calculate dietary iron bioavailability.
This longitudinal study will examine the effects of repeated bouts of operational stress and limited recovery on integrated MPS, whole-body protein balance, iron absorption, and aerobic performance. Following baseline characterization measures, active adults (n=24) representative of normal weight phenotype (NW; n=12) and overweight phenotype (OW; n=12) will complete a 48h balance phase preceding two rounds of repeated 72h energy deficit exposure each immediately followed by a 48h recovery phase. NW cutoff will be defined ≤ 22% body fat for males and ≤ 32% body fat for females. OW cutoff will be defined as \>22% body fat for males and \>32% body fat for females. These body composition cutoffs are informed by the maximum allowable percent body fat standards outlined in current Army Regulation 600-9. Additional details for determining % body fat are outlined in the experimental procedures section of the protocol.
Bioavailability of iron and zinc from habitual plant-based diets consumed by young children in Mexico is low due to the high phytate content. Whey protein has been found to increase zinc absorption, thus, providing a whey based supplement with micronutrients may be an effective strategy to increase iron and zinc bioavailability from plant-based foods and alleviate iron and zinc deficiencies. The investigators compared absorption of zinc and iron in children receiving diets with and without whey protein supplements (WPS).
Populations who consume non-fortified plant-based diets are at increased risk of iron and zinc deficiencies. The purpose of this randomized controlled study is to determine the absorption of iron and zinc from pearl millet biofortified with these two micronutrients. Forty children aged 2 years in Kanartaka, India are randomized to consume biofortified pearl millet (Group 1) or control pearl millet (Group 2) for two days. Quantities of zinc and iron absorbed are measured with established stable isotope extrinsic labeling techniques and analyses of duplicate diets.
The objective of the study is to develop a simple, noninvasive test for evaluation of iron absorption as a tool to determine the cause of iron deficiency anemia. Healthy, premenopausal women with iron deficiency with or without anemia will be recruited for the study. Participants will, over the course of two months, ingest an iron solution three times; after each iron ingestion, participants will collect their stool and bring it to the study investigators for assessment of iron content.
One of the targeted objectives of Healthy People 2020 is to reduce iron deficiency among women of reproductive age (WRA). Consuming foods rich in iron and/or oral iron supplementation is typically recommended to improve iron status; however, global rates of iron deficiency remain high. Thus, nutritional strategies to improve/maintain iron status are warranted. Dietary iron is found in two different forms: heme and non-heme iron. Non-heme iron is found in plant-based sources and is commonly used as a supplement and food fortificant. Absorption of non-heme iron is low compared to heme iron, which is found in animal sources, such as beef. Studies have also demonstrated that beef contains an unidentified factor that stimulates the absorption of non-heme iron. The primary objective of the proposed study is to determine the effects of incorporating daily meals containing beef or plant-based alternative with or without an iron supplement on indicators of iron status in iron-deficient WRA.
The two specific aims of this study are 1) to assess the relative contributions of two major maternal iron sources (i.e. dietary iron intake and red cell catabolism) at supplying iron to the fetus, and 2) to determine the impact of maternal and fetal iron status on placental transfer of these two iron sources in pregnant women and adolescents during the last trimester of pregnancy.
The three specific aims of this study are 1) to assess the impact of iron status on relative differences in absorption of heme and non-heme iron among pregnant women and non-pregnant women, 2) to assess the magnitude and the determinants of heme and non-heme iron transfer to the fetus over the last trimester of pregnancy, and 3) to characterize relationships between placental iron binding proteins with the enrichment of stable iron isotopes in the neonate at birth. The investigators hypothesize that there will be up regulation of heme and non-heme iron absorption and up regulation of placental iron transport proteins in response to low maternal iron stores.
This study will enroll at least 60 pregnant women in a randomized cross-over study in Dhaka, Bangladesh. Each participant will be randomized to one of 3 calcium doses: 500 mg, 1000 mg, 1500 mg elemental Ca per day. Each participant will undergo two calcium absorption tests, one with a micronutrient supplement powder containing non-encapsulated (non-coated) calcium and the other with a micronutrient supplement powder containing encapsulated calcium at the same dose. The absorption tests will be separated by a 2-week washout period. Fractional calcium absorption will be measured using the dual stable isotope method. For each test, the formulation will be administered orally for 9 days; on the 10th day, a 44Ca- labeled stable isotope will be given orally and a 42Ca-labeled stable isotope dose will be given intravenously. Urine will be collected for 48 hours to measure calcium absorption.