Diet Therapy

Background: Diet is one of the most modifiable behaviors affecting health. But diet assessment measures that are based on self-report can be inaccurate. Researchers want better ways to address the role of diet in chronic disease. They want to see if stable isotopes can be used to better assess what people eat. Objective: To see if stable isotopes can help scientists identify things people eat. Eligibility: Healthy adults ages 18 to 65 Design: Participants will be screened with a medical history and physical exam. They will have blood and urine tests. These tests will be repeated during the study. Participants will stay in the inpatient unit of the NIH in Phoenix, Arizona, for 13 weeks. For 7 days, participants will eat a diet prepared by the NIH kitchen. They will get balanced meals that are 50% carbohydrates, 20% protein, and 30% fat. Then participants will be randomly placed on one of 3 diets containing different percentages of carbohydrates from soda. Participants height and weight will be measured. The amount of fat and muscle in their body will be measured by body scans that are similar to x-rays. Participants will have oral glucose tolerance tests. They will consume a sugar drink and then give blood samples over 3 hours. Participants will give hair and stool samples. Participants will complete a diet questionnaire. It assesses their food intake over 24 hours. Participants will complete behavioral questionnaires and computer performance tests. Participants will have fat biopsies taken from their stomach and thigh. Participants will have three 24-hour stays in a metabolic chamber. It is used to measure metabolism.

This research aims to study the dual effectiveness of incorporating soluble fibre and osmotic carbohydrates (SOLOS), with or without restricting fructans and GOS, and present novel findings in managing GI symptoms in patients with functional bowel disorders with constipation. These findings may also support researchers and clinicians in shaping new dietary approaches in the management of general constipation symptoms.

Crohn's disease (CD), a type of inflammatory bowel disease (IBD), is on the rise globally. Although medical treatments have advanced, CD still leads to significant health issues due to disease progression and medication side effects. Exclusive enteral nutrition (EEN) is a recommended first-line treatment for pediatric CD, proving more effective than oral corticosteroids without side effects. However, EEN demands strict adherence, making it challenging for patients, particularly adults. In 2019, Levine et al. found that a combination of a specific diet (CD exclusion diet, CDED) and partial enteral nutrition (PEN) was as effective as EEN in inducing remission in pediatric patients, with better tolerance and adherence. CDED focuses on whole foods and aims to minimize harmful dietary components affecting the gut. In clinical practice, an adapted CDED (aCDED) has been used to provide more food choices, but it lacks validation in clinical trials. An aCDED that considers regional and seasonal food variations could enhance patient adherence and align with modern dietary preferences. This study aims to compare the quality of life during a flare up of Crohn's disease treated with standard of care or an adapted Crohn's disease exclusion diet with partial enteral nutrition in adult patients.

When a patient has dialysis some nutrients are lost in the process. Nutritional losses include protein, trace elements (i.e. zinc, copper and selenium) and water-soluble vitamins (Vitamins C and B). These nutrients are essential for normal body function, including a good immune system and nutritional status. For example, on average the protein losses during a dialysis session (the process where the blood is cleaned via a machine and special fluid) is equal to 6g of protein/day (which is the equivalent of the amount of protein in 1 egg). Protein needs for the general population are 0.8g protein per kg of body weight. Because people on dialysis lose protein via the dialysis, it is thought that these people need to eat more protein. Currently, in clinical practice for people receiving dialysis, the guidelines are to aim for 1.1 -1.4g of protein per kg of body weight. However, the research is old and very weak. Dialysis treatments have changed over the past 40 years, and the investigator does not know if the replacement of these nutritional losses is important to how well people do on dialysis and if they have any effect on survival. Previous research is mostly limited to haemodialysis (a type of dialysis that requires a machine which cleans the patients' blood via special filters) and peritoneal dialysis (this is a type of dialysis which happens via the patients' tummy). There is no research on the nutritional supplementation in home HD and nocturnal HD. Our research will investigate if a higher protein provision leads to a reduction is hospital admissions and improved outcomes in patients receiving dialysis.