5 Clinical Trials for Various Conditions
Over the past few decades, fructose consumption has risen significantly in the United States1. This sugar is increasingly being used as a sweetener in a variety of foods1. Because there is a limited absorptive capacity for fructose, excessive ingestion of fructose leads to fructose malabsorption and dietary fructose intolerance (DFI) 2-9, 13. Incomplete absorption of fructose may lead to a variety of gastrointestinal symptoms, including bloating, pain, gas and diarrhea 2-9. In tertiary care centers, the prevalence of DFI in subjects with unexplained GI symptoms has been estimated to range between 11-50 %, when subjects were assessed with breath tests following administration of 25 grams of fructose 2, 5-7. Currently, the main treatment for DFI consists of restricting the intake of fructose-containing foods 10-12 or limiting the intake of foods with excess "free fructose" (ie, fructose in excess of glucose) or a high fructan content17. These diet restrictions can improve symptoms in patients with DFI 10-12,17. However, the diet is very restrictive and imposes a significant burden on the individual and the family. In one study, 40% of subjects were unable to comply with dietary restrictions 10. Currently, there are no other therapeutic agents for treating this condition 14, 15. Apart from promoting intestinal fructose absorption, an ideal therapeutic agent should be safe, simple to use, inexpensive and have no calorific value. Fructose is mostly absorbed in the small intestine by facilitated diffusion which is mediated by the GLUT-5 transporter protein. This protein is expressed on the intestinal mucosal surface. In the presence of glucose, fructose absorption is increased, mostly due to co-transport with glucose via the GLUT-2 transporter protein. However, the calorie content of glucose precludes its routine use in patients with DFI. Other compounds that promote fructose absorption, such as 3 O-methyl glucose and epidermal growth factor (EGF) have significant side effects and safety issues, making them unsuitable for clinical use in DFI. Several amino acids, including alanine, have been also been shown to increase intestinal fructose absorption 14. The postulated mechanism is as follows: transmucosal Na+-coupled amino acid transport causes increased water flow through the mucosal apical membrane14. This, in turn, facilitates fructose absorption by a process of 'solvent drag', caused by an increase in intraluminal fructose concentration caused by water removal from the lumen14. The potential benefit of alanine was assessed in a European study in healthy children 14. Ten subjects underwent H2 breath tests following administration of fructose alone (2g/ Kg body weight), followed by a combination of fructose and an equi-molar dose of various amino acids (L-alanine, L-phenylalanine, L-glutamine, L-proline) or glucose. Breath H2 production was assessed as a marker of intestinal fructose absorption. Subjects were asked to report any gastrointestinal symptoms during the test. All subjects had a positive (\>20 ppm of H2) breath test (68 ± 38 ppm) with fructose and 6/10 subjects reported either abdominal pain or diarrhea during the test. Co-administration of alanine caused a significant (p \< 0.05) decrease in breath H2 production (3 ± 3 ppm), suggesting increased intestinal fructose absorption. Furthermore, none of the subjects reported any gastrointestinal symptoms during the test.
Data suggest that alanine may facilitate the intestinal absorption of fructose in patients with DFI and thereby may decrease GI symptoms. We hypothesize that the ingestion of supplemental L-alanine along with mixed meals or snacks that contain foods with free fructose or high fructose content will decrease GI symptoms in subjects with dietary fructose intolerance by facilitating intestinal absorption of fructose. Aim: To investigate the effects of co- administration of equi-molar doses of L-alanine or placebo on the occurrence of GI symptoms in subjects with dietary fructose intolerance, in a randomized, double blind, cross over study. Methods: We propose to investigate the effects of co-administration of equi-molar doses of L-alanine or placebo on the occurrence of GI symptoms in 70 subjects with dietary fructose intolerance, in a randomized, double blind, cross over study. Data Analysis: The primary outcome measure will be a comparison of baseline breath sample values and study visit breath sample values. Additionally, we will assess subject-reported occurence and severity of nine gastrointestinal symptoms during the test on a visual analog scale (VAS). Expected Results: We anticipate that dietary fructose intolerance (DFI) symptoms will improve with ingestion of supplemental L-alanine (along with foods containing free fructose or high fructose content). We additionally expect treatment of DFI with administration of L-alanine powder to be more practical than co-ingestion of alanine-rich foods, and more convenient for patients.
Background: Over the past few decades, fructose is increasingly being used as a sweetener/ additive in a variety of foods. Incomplete absorption of fructose has been implicated as a cause of gastrointestinal symptoms. In tertiary care centers, the prevalence of fructose malabsorption in subjects with unexplained GI symptoms is thought to be between 11-50%, when assessed with breath tests following administration of 25 grams of fructose in a 10% solution. Restriction of dietary fructose has been shown to improve symptoms in these patients to an extent. Currently, there are no therapeutic agents that improve intestinal fructose absorption and thereby decrease symptoms. Studies in the pediatric population have shown that fructose absorption in the small intestine is increased in the presence of glucose or amino acids, especially alanine. Objective: The investigators' objective is to assess whether co-administration of an oral solution of L-alanine facilitates fructose absorption and decreases gastrointestinal (GI) symptoms associated with fructose malabsorption in subjects undergoing standard fructose breath test when compared to placebo. Methods and analysis: The investigators propose a randomized, double-blind study in 40 subjects with known fructose intolerance. After an overnight fast, each subject will receive an oral solution of 12.5 grams of alanine in 125cc of water or placebo. Next, the subject will receive an oral solution of 25 grams of fructose in a 10% solution. Serum, urine and breath samples will be collected at baseline and at 30-minute intervals for 4 hours. GI symptoms will also be assessed and recorded at 30 minute intervals using a standard questionnaire. Repeated measures ANOVA will be used to compare the data obtained during the study protocol with the baseline (pre-study) data. Expected outcomes: Co-administration of alanine with fructose may improve fructose absorption and decrease symptoms in subjects with fructose intolerance. Hypothesis: Ingestion of alanine along with fructose, will facilitate intestinal absorption of fructose in subjects with fructose malabsorption. Aim: To investigate the effects of co-administration of equi-molar doses of alanine on a) the absorption of fructose and b) the occurrence of GI symptoms in subjects with fructose malabsorption.
Early Check provides voluntary screening of newborns for a selected panel of conditions. The study has three main objectives: 1) develop and implement an approach to identify affected infants, 2) address the impact on infants and families who screen positive, and 3) evaluate the Early Check program. The Early Check screening will lead to earlier identification of newborns with rare health conditions in addition to providing important data on the implementation of this model program. Early diagnosis may result in health and development benefits for the newborns. Infants who have newborn screening in North Carolina will be eligible to participate, equating to over 120,000 eligible infants a year. Over 95% of participants are expected to screen negative. Newborns who screen positive and their parents are invited to additional research activities and services. Parents can enroll eligible newborns on the Early Check electronic Research Portal. Screening tests are conducted on residual blood from existing newborn screening dried blood spots. Confirmatory testing is provided free-of-charge for infants who screen positive, and carrier testing is provided to mothers of infants with fragile X. Affected newborns have a physical and developmental evaluation. Their parents have genetic counseling and are invited to participate in surveys and interviews. Ongoing evaluation of the program includes additional parent interviews.
Bloating, gas, pain and diarrhea are common complaints. Routine investigations are negative; these patients are labeled as IBS. In these patients, whether testing for carbohydrate malabsorption or small intestinal bacterial overgrowth (SIBO) is useful is unclear. Investigators aim to assess the prevalence of SIBO, fructose and lactose intolerance, the usefulness of breath tests, and predictive value of pre-test symptoms.