Hassan S. Dashti, Ph.D., R.D.

Assistant Investigator
Anesthesia, Critical Care and Pain Medicine, Mass General Research Institute

Assistant Professor of Anaesthesia
Harvard Medical School

B.A. University of Pennsylvania 2010

Ph.D. Tufts University 2015

M.S. Tufts University 2012

circadian rhythms; clinical trials; electronic health records; genetic epidemiology; large biobanks; nutrition; parenteral nutrition; perioperative care; precision medicine; sleep; wearables

The Dashti Lab leads clinical and translational nutrition research focused on the sleep and circadian rhythms of patients with nutrition-related challenges. The goal of this research is to provide tailored medical treatments and therapies that are less disruptive to sleep and circadian rhythms across diverse patient populations.

Ongoing Projects

Reevaluating standard clinical nutrition practices to support Circadian Medicine in the Intensive Care Unit (ICU)

Clinical care practices and current environments in intensive care units (ICUs) are not optimized to support circadian rhythms or sleep of patients. ICU settings are known to severely fragment sleep and abolish circadian rhythms of critically ill patients. Ongoing efforts to mitigate disruption are non-pharmacological interventions targeting light and noise, which have successfully promoted sleep and reduced delirium risk in ICU patients. Among the contributing factors is the common practice of administering nutrition support through feeding tubes (enteral nutrition) or intravenously (parenteral nutrition) at night. Although nutrition support is known to improve clinical outcomes, this current practice affecting approximately 250,000 US hospital admissions annually lacks a medical rationale. The objective of this study is to examine a novel dimension of clinical nutrition by determining whether prioritizing sleep quality and preserving robust circadian rhythms through a circadian-conscious feeding regimen improves patient outcomes. You can learn more about our ongoing trial here. This project is generously supported by the NIH National Heart, Lung, and Blood Institute (NHLBI).

Sleep Health for adult consumers of Home Total Parenteral Nutrition (TPN)

Parenteral nutrition (PN) is the provision of nutrients intravenously to treat or prevent malnutrition for people who cannot adequately eat by mouth or absorb enough nutrients because of disease or intestinal surgery. It is considered standard clinical practice for patients who are consuming home parenteral nutrition (HPN) to receive infusions for 12-hour periods overnight, coinciding with sleep. Overnight infusion is considered the preferred administration method as it allows time off the feeds and physical freedom from infusion pumps during the day. Consequently, poor sleep is common among consumers of HPN because of polyuria, infusion pump alarms, and fear of catheter dislodgment. In our 7‐day home actigraphy study of 20 patients receiving HPN, we found that most consumers of HPN do not meet current recommendations for sleep duration and quality. We also reported that daytime HPN is feasible and safe in free-living adults with SBS and, compared with overnight HPN, is associated with better subjective sleep without increasing 24-h glucose concentrations. The goal of this community sleep health project led by a multidisciplinary team of scientists and patient representatives is to identify opportunities to support the sleep of adult consumers of HPN. This project is generously supported by the American Academy of Sleep Medicine and the ASPEN Rhoads Research Foundation.

The role of circadian rhythms and sleep in Eating Disorders

There is a known bidirectional relationship between circadian rhythms and sleep and many psychiatric disorders such as depression, schizophrenia, and bipolar disorders. Eating disorders such as anorexia nervosa and binge eating disorder have the highest mortality rates of all psychiatric diseases. While there is some preliminary evidence implicating the circadian system in eating disorders primarily centered on the link between binge eating disorder and evening chronotype, the relevance of the circadian system in eating disorders remains largely unknown. Additional evidence also suggests perturbations in sleep-wake cycles including morning awakening insomnias among people with anorexia nervosa. Whether the effects are mediated by mood and anxiety pathophysiology that often cluster with eating disorders remains unknown. The aim of these studies is to further investigate the relationship between eating disorders and the circadian system and sleep traits through complementary genetic and non-genetic analyses. We recently found that in contrast to other metabo-psychiatric diseases, anorexia nervosa is a morningness eating disorder and further corroborate findings implicating insomnia in anorexia nervosa. However, more research in diverse populations and with subtypes of anorexia nervosa are warranted.

Multimodal Prehabilitation for older adult cancer patients

There is an increasing number of older, frail, and vulnerable patients presenting for surgical care, however these patients are often not optimized prior to surgery. Multimodal prehabilitation is a suite of preventative interventions offered to surgical candidates intended to optimize wellbeing before surgery. Existing programs, however, primarily focus on nutrition and/or physical function and often enroll low-risk patients who may not benefit from prehabilitation. The aim of this study is to develop a multimodal prehabilitation program at Mass General for at-risk older adult patients who have previously undergone neoadjuvant chemotherapy or radiotherapy and are scheduled for surgical removal of esophageal cancer. You can learn more about the ongoing trial here. This project is generously supported by the Center for Aging and Serious Illness (CASI) at MGH.

Select Publications and News

Study: The Role of Circadian Rhythms and Sleep in Anorexia Nervosa
News (Forbes): Being A Morning Person Linked To Higher Anorexia Risk, Study Finds
News (Harvard Gazette): Harvard researchers see genetic link between anorexia, early rising

Study: Is there an association between daytime napping, cognitive function, and brain volume? A Mendelian randomization study in the UK Biobank
News (CNN): Daytime naps may be good for our brains, study says

Study: Genetic determinants of daytime napping and effects on cardiometabolic health
News (Harvard Gazette): The science of siestas

Study: Genome-wide association study identifies genetic loci for self-reported habitual sleep duration supported by accelerometer-derived estimates
News (Harvard Gazette): Study identifies gene regions associated with sleep duration

Study: Night Shift Work, Genetic Risk, and Type 2 Diabetes in the UK Biobank
News (The New York Times): Working Nights May Raise Diabetes Risk

Funding

National Heart, Lung, and Blood Institute (NIH)
ASPEN Rhoads Research Foundation
American Academy of Sleep Medicine
Massachusetts General Hospital
Boston Nutrition Obesity Research Center

Principal Investigator

Dr. Hassan S. Dashti is an Assistant Professor in the Department of Anesthesia, Critical Care and Pain Medicine at Massachusetts General Hospital (MGH), Harvard Medical School. He is a registered dietitian and a research scientist with interest in clinical nutrition, chronobiology, sleep, and genetics. His research seeks to understand the bidirectional relationship between nutrition and sleep and the role of food timing as a cardiometabolic disease risk factor in healthy and patient populations. His work is funded by grants from the NIH-NHLBI, ASPEN Rhoads Research Foundation, and the American Academy of Sleep Medicine. He also currently serves as an Associate Editor for American Society for Nutrition's journal Advances in Nutrition. He completed his postdoctoral training at MGH’s Center of Genomic Medicine working with Dr. Richa Saxena on unraveling the genetic basis of sleep and circadian traits. He received his PhD from Tufts University’s Friedman School of Nutrition after which he completed his dietetic internship at Brigham and Women’s Hospital, Boston MA.

Team Members

Current:

Former:

Collaborations

The success of our projects is contingent on collaborations with scientists, clinicians, and patients all over the world. Please do not hesitate to contact us for collaboration or research opportunities.

Publications

hassan.dashti@mgh.harvard.edu

(617) 726-9132

Anesthesia, Critical Care and Pain Medicine
Edwards Research
60 Blossom Street
410C
Boston, MA 02114-2621

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