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47 active trials for Diet Modification

Meat-based Versus Pesco-vegetarian Diet and Colorectal Cancer

Colorectal cancer (CRC) is strongly affected by diet, with red and processed meat increasing risk. To understand the role of microbiome in this phenomenon and to identify specific microbiome/metabolomics profiles associated with CRC risk, will be studied: 1) healthy volunteers fed for 3 months with: a high-CRC risk diet (meat-based MBD), a normalized CRC risk diet (MBD plus alpha-tocopherol, MBD-T), a low-CRC risk diet (pesco-vegetarian, PVD). At the beginning and at the end of the intervention, gut microbiome profiles (metagenomics and metabolomics), and CRC biomarkers (genotoxicity, cytotoxicity, peroxidation in faecal water; lipid/glycemic indexes, inflammatory cytokines, oxidative stress), 2) Colon carcinogenesis: the same diets will be fed (3 months) to carcinogen-induced rats or to Pirc rats, mutated in Apc, the key gene in CRC; faecal microbiome profiles, will be correlated to carcinogenesis measuring preneoplastic lesions, colon tumours, and faecal and blood CRC biomarkers as in humans; 3) To further elucidate the mechanisms underlying the effect of different microbiomes in determining CRC risk, faeces from rats fed the experimental diets will be transplanted into carcinogen-induced germ-free rats, measuring how microbiome changes correlate with metabolome and disease outcomes. The results will provide fundamental insight in the role of microbiome in determining the effect of the diet, in particular red/processed meat intake, on CRC risk

Start: June 2019

Cannabinoid Supplementation on Vascular and Cognitive Function

Cannabidiol (CBD) is a bioactive cannabinoid compound in marijuana (cannabis sativa), but unlike ?9 tetrahydrocannabinol (THC), lacks the psychoactivity effect of THC. Available evidence suggests that there are marked therapeutic CBD effects for diverse disease processes including inflammation, cancers, psychosis, and epileptic seizures. The purpose of this study, in both younger and older healthy humans, is to improve our understanding of how CBD might control and regulate blood vessel health as well as cognitive and exercise performance.

Start: January 2018

Dynamic Connectivity Under Metabolic Constraints

The investigators are studying the impact of insulin resistance on the acceleration of brain aging and testing whether increased neuron insulin resistance can be counteracted by utilization of alternate metabolic pathways (e.g., ketones rather than glucose). This study has three Arms, which together provide synergistic data. For all three Arms, subjects are tested in a within-subjects design that consists of 2-3 testing sessions, 1-14 days apart, and counter-balanced for order. Impact of fuel (glucose in one session, ketones in the other) on brain metabolism and associated functioning is measured during each session. For Arms 1-2, the primary experimental measure is functional magnetic resonance imaging (fMRI), which is used to trace the self-organization of functional networks following changes in energy supply and demand. Arm 1 tests the impact of endogenous ketones produced by switching to a low carbohydrate diet, while Arm 2 tests the impact of exogenous ketones consumed as a nutritional supplement. For Arm 3, simultaneous magnetic resonance spectroscopy/positron-emission tomography (MR/PET) is used to quantify the impact of exogenous ketones on production of glutamate and GABA, key neurotransmitters. Subjects will be given the option to participate in more than one of the Arms, but doing so is not expected nor required. Prior to scans, subjects will receive a clinician-administered History and Physical (H&P), which includes vital signs, an oral glucose tolerance test (OGTT), and the comprehensive metabolic blood panel. These will be used to assess diabetes, kidney disease, and electrolytes. If subjects pass screening, they will be provided the option to participate in one or more Arms, which include neuroimaging. To provide a quantitative measure of time-varying metabolic activity throughout the scan, based upon quantitative models of glucose and ketone regulation, as well as to be able to implement safety stopping rules (see below), the investigators will obtain pin-prick blood samples three times: prior to the scan, following consumption of the glucose or ketone drink, and following completion of the scan. To assess effects of increased metabolic demand, the investigators measure brain response to cognitive load, transitioning from resting-state to spatial reasoning through a spatial navigation video task. To assess effects of increased metabolic supply, the investigators measure brain response to glucose or ketone bolus.

Start: June 2015

Diet and Sleep Monitoring

This study will investigate the effect of two dietary patterns on sleep outcomes and measures of reported appetite. Participants will be given two different diets on two separate stays.

Start: August 2017

A Home-based Intervention to Improve the Diet Quality of Preschoolers

U.S. children eat too little fruits and vegetables and whole grains, and too many energy dense foods, dietary behaviors associated with increased morbidity from cardiovascular diseases. Parents play a key role in shaping their child's diet and best practices suggest that parents should involve children in food preparation, offer, model and encourage a variety of healthy foods. In addition, while parents help to shape food preferences, not all children respond in the same way and certain appetitive traits, such as satiety responsiveness (sensitivity to internal satiety signals), food responsiveness (sensitivity to external food cues), and enjoyment of food may help explain some of these differences. Prior interventions among preschool aged children to improve their diet have not used a holistic approach that fully targets the home food environment, by focusing on food quality, food preparation, and positive feeding practices while acknowledging a child's appetitive traits. This proposal will build upon pre-pilot work to develop and pilot-test the feasibility, acceptability and preliminary efficacy of a novel home-based intervention. The proposed 6-month intervention, will include 3 monthly home visits by a community health worker (CHW) trained in motivational interviewing, that include in-home cooking demos. In between visits, parents will receive tailored text-messages 2x/wk. and monthly mailed tailored materials. During the last 3 months CHW phone calls will replace the home visits. The intervention will be tailored for individual families based on the child's appetitive traits. The proposed research will lay the groundwork for a larger trial to support, motivate, and empower low-income parents to prepare healthy meals and use healthy feeding practices, which will improve children's diets and ultimately their health.

Start: July 2019

Low Energy Diet and Familial Partial Lipodystrophy

To evaluate the therapeutic efficacy and metabolic impact of a low energy diet (LED) in people with familial partial lipodystrophy and diabetes. Participants will be provided with a LED (total diet replacement) for 12 weeks, before the introduction of a stepped food transition. Metabolic effects will continue to be assessed for 1 year. In order to better understand why this intervention changes insulin sensitivity, we will also collect adipose and muscle tissue samples at baseline and 12 weeks into the intervention in participants willing to have these procedures performed. These samples will be used for histological, metabolite, gene expression and protein expression analyses.

Start: July 2019

Azithromycin Insulin Diet Intervention Trial in Type 1 Diabetes

Increasing evidences suggest that infections are important etiological factors for the development of Type 1 Diabetes (T1D). The overall hypothesis of the study is that the treatment of children, during the first year after diagnosis of T1D with Azithromycin, combined with repeated episodes of intensified insulin treatment to induce maximal beta-cell rest, and dietician support to promote dietary habits that minimize the likelihood of bacterial reflux from the duodenum to the pancreatic duct, will lead to preservation of beta cell function. This trial will examine whether the AIDIT protocol initiated within one week from diagnosis could preserve insulin production in children with Type 1 Diabetes.

Start: September 2018