ALL LACTOSE INTOLERANCE ARTICLES
Yuying Luo, MD
Medical Reviewer
Yuying Luo, MD, is an assistant professor of medicine at Mount Sinai West and Morningside in New York City. She aims to deliver evidence-based, patient-centered, and holistic care for her patients.
Her clinical and research focus includes patients with disorders of gut-brain interaction such as irritable bowel syndrome and functional dyspepsia; patients with lower gastrointestinal motility (constipation) disorders and defecatory and anorectal disorders (such as dyssynergic defecation); and women’s gastrointestinal health.
She graduated from Harvard with a bachelor's degree in molecular and cellular biology and received her MD from the NYU Grossman School of Medicine. She completed her residency in internal medicine at the Icahn School of Medicine at Mount Sinai, where she was also chief resident. She completed her gastroenterology fellowship at Mount Sinai Hospital and was also chief fellow.
Sanjai Sinha, MD
Medical Reviewer
Dr. Sinha did his undergraduate training at the University of California in Berkeley, where he graduated magna cum laude. He earned his medical degree at the Albert Einstein College of Medicine in New York City in 1998 and completed his internship and residency training at the New York University School of Medicine in 2001. Subsequently, he worked with the Department of Veterans Affairs from 2001 to 2012 and held faculty appointments at both the Mount Sinai School of Medicine and Columbia University College of Physicians and Surgeons.
In 2006, he won the VISN3 Network Director Award for Public Service and a commendation from the secretary of Veterans Affairs for his relief work after Hurricane Katrina. He joined Weill Cornell Medical College in 2012, where he is an assistant professor of clinical medicine and the director of the care management program, as well as a practicing physician.
In addition to his work for Everyday Health, Sinha has written for various publications, including Sharecare and Drugs.com; published numerous papers in peer-reviewed medical journals, such as the Journal of General Internal Medicine; and presented at national conferences on many healthcare delivery topics. He is a fellow of the American College of Physicians.
Reyna Franco, RDN
Medical Reviewer
Reyna Franco, RDN, is a New York City–based dietitian-nutritionist, certified specialist in sports dietetics, and certified personal trainer. She is a diplomate of the American College of Lifestyle Medicine and has a master's degree in nutrition and exercise physiology from Columbia University.
In her private practice, she provides medical nutrition therapy for weight management, sports nutrition, diabetes, cardiac disease, renal disease, gastrointestinal disorders, cancer, food allergies, eating disorders, and childhood nutrition. To serve her diverse patients, she demonstrates cultural sensitivity and knowledge of customary food practices. She applies the tenets of lifestyle medicine to reduce the risk of chronic disease and improve health outcomes for her patients.
Franco is also a corporate wellness consultant who conducts wellness counseling and seminars for organizations of every size. She taught sports nutrition to medical students at the Albert Einstein College of Medicine, taught life cycle nutrition and nutrition counseling to undergraduate students at LaGuardia Community College, and precepts nutrition students and interns. She created the sports nutrition rotation for the New York Distance Dietetic Internship program.
She is the chair of the American College of Lifestyle Medicine's Registered Dietitian-Nutritionist Member Interest Group. She is also the treasurer and secretary of the New York State Academy of Nutrition and Dietetics, having previously served in many other leadership roles for the organization, including as past president, awards committee chair, and grant committee chair, among others. She is active in the local Greater New York Dietetic Association and Long Island Academy of Nutrition and Dietetics, too.
Natalia Johnsen, MD
Medical Reviewer
Natalia Johnsen, MD, is a triple board-certified physician in internal medicine, lifestyle medicine, and obesity medicine, practicing as an internist and consultant at the Vancouver Clinic in Vancouver, Washington.
Dr. Johnsen began her medical career as an ob-gyn in Russia before relocating to the United States in 2000. She completed her internal medicine internship at the University of Nevada and her residency at a Stanford-affiliated program in Santa Clara, California.
Deeply interested in the impact of lifestyle on both physical and mental health, Johnsen transitioned her focus toward prevention-based care after witnessing how many chronic conditions could be avoided or improved through lifestyle interventions. She became board-certified in lifestyle medicine in 2021 and further expanded her expertise by earning board certification in obesity medicine in 2025.
Johnsen is passionate about empowering patients with evidence-based tools to achieve sustainable health and long-term well-being.
Michelle Seguin, MD
Medical Reviewer
Michelle Seguin, MD, is a board-certified family medicine, lifestyle medicine, and certified functional medicine physician (IFMCP). She is a practicing physician at Root Functional Medicine, a leading telemedicine practice specializing in personalized, root-cause care.