Atlantic Digestive Specialists

Helping people inside & out

  • Our Physicians
    • Aristotle J. Damianos, MD
    • Roger M. Epstein, MD
    • Brian H. Hyett, MD
    • Sukeerti Kesar, MD
    • Jennifer Lewis, MD
    • Sean P. Lynch, MD
    • William E. Maher, MD
    • Khushboo Munot, MD
    • Robert A. Ruben, MD
    • Sonya Alyea, APRN
    • Shelby Menard, APRN
    • Alyssa Young, APRN
    • Robert Ketchum, PA
    • Kathy Gibson, PA
    • Kerry Loan, PA
    • Rachel Whitman, PA
    • Jenna Adams, FNP
  • Conditions
    • Acid Reflux
    • Eosinophilic Esophagitis
    • Irritable Bowel Syndrome (IBS)
    • Barrett’s Esophagus
    • Food Allergies
    • Lactose Intolerance
    • Celiac Disease
    • Esophageal Diseases
    • Liver Disease
    • Cirrhosis
    • Gallstones
    • Nausea/Vomiting
    • C. Difficile Infection (C. diff)
    • Gastroesophageal Reflux (GERD)
    • Obesity
    • Colorectal Cancer
    • GI Infections
    • Pancreatitis
    • Constipation
    • Heartburn
    • Peptic Ulcers
    • Crohn’s Disease
    • Hemorrhoids
    • Polyps
    • Diarrhea
    • Hepatitis
    • Ulcerative Colitis
    • Diverticulitis
    • Inflammatory Bowel Disease (IBD)
  • Procedures
    • Bacterial Overgrowth Breath Test (SIBO)
    • Colon Cancer Screening
    • Colonoscopy
    • Endoscopic Retrograde Cholangiopancreatography
    • Endoscopic Ultrasound (EUS)
    • Esophageal Manometry
    • Esophagogastroduodenoscopy
    • Helicobacter Pylori Breath Test
    • Lactose Intolerance Breath Test
    • Liver Biopsy
    • pH Probe Placement – Impedance
    • Photodynamic Therapy
    • Radiofrequency Ablation of Barrett’s Esophagus
    • Video Capsule Endoscopy
  • Prep Instructions
    • Colonoscopy Preparations
      • Gatorade Miralax Colon Prep Instructions
      • Mag Citrate Colon Prep Instructions
      • Moviprep Colon Prep Instructions
      • Nulytely Colon Prep Instructions
      • 5 Day Miralax/Nulytely Prep Instructions
      • OSMO Pill Colon Prep Instructions
      • Prepopik Split-Dose Colon Prep Instructions
      • Suprep Split-Dose Colon Prep Instructions
    • Sigmoidoscopy Preparations
      • Sigmoidoscopy Hospital Prep Instructions
      • Sigmoidoscopy In-Office Prep Instructions
    • Upper Endoscopy Preparations
      • Esophageal Manometry Prep Instructions
      • Upper Endoscopy Hospital Prep Instructions
      • Upper Endoscopy In-Office Prep Instructions
    • Other Preparations
      • H-Pylori Breath Test Prep Instructions
      • Lactose Tolerance Testing Prep Instructions
      • Outpatient Liver Biopsy Prep Instructions
  • For Patients
    • Patient Portal
    • Patient Forms
    • Frequently Asked Questions
    • Colorectal Cancer Screening Guidelines
    • Insurance Accepted
    • Our Affiliates
    • Testimonials
    • Patient Reviews
    • News and Events
    • Health Links
    • Notice of Non-Discrimination
    • Video Gallery
  • Locations
  • Pay Your Bill
  • Notice of Data Security Incident

Physician Assistant Rachel Whitman Joins Atlantic Digestive Specialists

February 29, 2020 By julie

Rachel Whitman, PA

Rachel Whitman, MS, PA-C, joins the medical team at Atlantic Digestive Specialists.

Certified by the National Commission on Certification of Physician Assistants, Rachel earned her master’s degree at the University of New England, College of Health Professions in Portland. She most recently worked at Newburyport Gastroenterology in Massachusetts.

Rachel is experienced in managing acute and chronic diseases of the liver and digestive tract. She is now seeing patients in the Portsmouth office at Atlantic Digestive Specialists.

Atlantic Digestive Specialists is the region’s foremost gastroenterology physician practice treating diseases associated with the esophagus, stomach, intestines, liver, pancreas, and other digestive organs. Drs. Baquero, Damianos, Epstein, Flavin, Grondin, Hyett, Lewis, Lynch, Maher, Mahmoud, and Ruben are all board-certified gastroenterologists with more than 100 years of combined experience.

With offices in Somersworth and Portsmouth, Atlantic Digestive Specialists is dedicated to providing the most comprehensive services related to the digestive system and are trusted colonoscopy and endoscopy providers.

Gastroenterologist Position

February 24, 2020 By julie

Atlantic Digestive Specialists, the largest private GI practice in New Hampshire, with eleven physicians, two Physician Assistants and two Nurse Practitioners, seeks a gastroenterologist to join us in the summer of 2020.

We have three offices located in the seacoast region of the state, and practice at four hospitals and three separate ASCs. We are seeking a Fellowship-trained physician who is looking for a long-term career opportunity. Training in EUSs and ERCPs is strongly preferred. We offer a two-year track to partnership, with competitive guaranteed salary that includes bonus potential. Full comprehensive benefits. Opportunities for ASC ownership available. J-1visa candidates will be considered.

To discuss this opportunity please send your resume to David Hutton, Practice Administrator at [email protected] or call him at (603) 841-1302.

You can also check us out at www.atlanticdigestive.com.

New Hampshire was recently ranked by U.S. News and World Report as the second best state in the United States to live, including ranking fourth in healthcare, third in education, and first in opportunity. The state has no income or general sales tax.

Dalia Mahmound, MD, joins the medical team at Atlantic Digestive Specialists.

August 5, 2019 By julie

Board-certified in gastroenterology and internal medicine, Dr. Mahmoud has a special interest in treating diseases of the bile ducts, liver, and pancreas.

Dr. Mahmoud has fellowship training in advanced endoscopy from New-York-Presbyterian Brooklyn Methodist Hospital, where she most recently worked, and received training in performing therapeutic endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic ultrasound (EUS) procedures, as well as large polyp removal.

Dr. Mahmoud is now accepting patients at our Portsmouth office.  Call (603) 692-2228 to make an appointment.

Atlantic Digestive Specialists provides free colonoscopies every March

April 14, 2019 By julie

The physicians at Atlantic Digestive Specialists are committed to the health and wellbeing of the communities we serve. Each spring, during Colorectal Cancer Awareness Month, we donate screening colonoscopies to eligible patients in the Seacoast. Working with Families First and Lamprey Health Care this year, Drs. Epstein, Hyett, and Grondin performed colonoscopies at Portsmouth Regional Hospital.

Led by Dr. Roger Epstein, we have been offering this program every March for the past nine years.

“Most of us think of a colonoscopy as unpleasant and approach it with dread and fear,” said Jane Cummings, RN, about the program in a past post. “Our patients view it as a positive experience and appreciate the opportunity to receive a health screening that they are not able to afford. This is a great collaboration of the public and private sector resulting in preventive health services to the uninjured in the Seacoast community.”

Physicians typically perform about twenty colonoscopies on select Saturdays in March and patients never receive a bill.

Dr. Ruben, Dr. Maher & Dr. Grondin are Voted Top Doctors in NH for the 3rd year in a row!

April 7, 2019 By julie

The results are in — New Hampshire physicians have selected Dr. Robert Ruben, Dr. William Maher, and Dr. Marylyn Grondin as “Top Docs”  — placing them in the top 25% of gastroenterologists in the granite state.

A poll conducted by NH Magazine asks all licensed physicians in NH to choose who they would have provide medical care for their friends and loved ones. Drs. Ruben, Maher, and Grondin were selected as top gastroenterologists.

Top Gastroenterologists in NH

The nine board-certified gastroenterologists at Atlantic Digestive Specialists serve people throughout southern Maine and the seacoasts of New Hampshire and Massachusetts.

Dr. Ruben received his undergraduate degree from Brandeis University and his medical degree from the University of Vermont (UVM). His internship and residency was completed at the University of Colorado Health Sciences Center. Dr. Ruben obtained one year special training in Pathology at UVM and completed a fellowship in gastroenterology at Brigham and Women’s Hospital in Boston. He is a former clinical instructor of medicine at Harvard University Medical School.

Dr. William Maher received his undergraduate degree from Rutgers University and his medical degree from the University of Medicine and Dentistry of New Jersey Hospital. His internship and residency in Internal Medicine and his fellowship in gastroenterology was completed at Strong Memorial Hospital at the University of Rochester, New York. Dr. Maher completed a fellowship for advanced training in Therapeutic Endoscopy at the University of Wisconsin.

Dr. Grondin received her medical degree from LaSalle University and a Clinical Certificate from the College of Medicine and Dentistry of New Jersey. She completed her internship and residency at Bridgeport Hospital, an affiliate of Yale University Medical School. Dr. Grondin completed her fellowship in gastroenterology at West Virginia University School of Medicine, where she continued on staff there as an Assistant Professor for three years. Dr. Grondin is a clinical instructor of medicine at Harvard Medical School.

« Previous Page
Next Page »
Copyright © 2026 Atlantic Digestive Specialists, All Rights Reserved

  • facebook
  • youtube
MENU
  • Home
  • Patient Portal
  • Pay My Bill
  • About Us
  • Locations
  • Meet Our Trusted Physicians
  • Conditions Treated
  • Procedures Performed
  • Prep Instructions
  • Patient Resources
  • Contact Us