Dr. Jay Luthar, MD, DipABLM, and Dr. Julia Loewenthal, MD have been named 2026 Castle Connolly Top Doctors, marking the second year they have received this prestigious designation. Only 7 percent of the nation's licensed physicians are chosen each year as Castle Connolly Top Doctors for their specialties in their regions. Drs. Luthar and Loewenthal are physicians with Lutanen Health, a bespoke primary care and longevity practice in Boston's Back Bay that prioritizes deep, sustained patient relationships and strategic life-wide health stewardship over volume-based care.
At Lutanen Health, each doctor cares for no more than 150 patients, allowing for extended visits, same-day appointments, 24/7 physician access, and individualized nutrition counseling. The practice is the only academically affiliated primary care practice in Boston where longevity science is integrated into everyday care. Dr. Luthar emphasized the importance of time, trust, and partnership in medicine, stating that care should be uniquely designed for each patient. By understanding a patient's biology, context, and goals over time, the team offers care that is both effective and deeply human.
The recognition from Castle Connolly highlights the physicians' commitment to identifying risk long before symptoms emerge and allocating interventions across a life span to preserve vigor and delay decline. Drs. Luthar and Loewenthal are fellowship trained in integrative medicine, bringing mind-body science and holistic approaches to lifestyle optimization. Their newly designed 3,000 square foot healing space in Back Bay includes a state-of-the-art human performance laboratory.
Lutanen Health focuses on metabolic health, cardiovascular risk reduction, cognitive preservation, and healthy aging. The clinical team specializes in managing complex internal medicine cases while addressing the unique needs of older patients, including frailty risk, medication optimization, and age-related vitality. Advanced diagnostic technologies employed include AI-guided plaque detection, multi-cancer early detection blood testing, VO₂ max testing, biological age tracking, advanced biomarker and genetic analysis, comprehensive fitness and mobility assessment, and structured sleep evaluation.
Dr. Luthar completed his medical residency at Cambridge Hospital, a Harvard Internal Medicine Residency Site, and is board-certified in Internal Medicine, Integrative Medicine, and Lifestyle Medicine. Dr. Loewenthal completed her Internal Medicine residency at Brigham and Women's Hospital and her fellowship in Geriatric Medicine through the Harvard Multi-Campus Geriatrics Program. She is board-certified in Internal Medicine and Geriatric Medicine, and board eligible in Integrative Medicine. Both physicians maintain academic faculty roles at Harvard Medical School, where Dr. Luthar serves as an Instructor and Dr. Loewenthal as an Assistant Professor. Their work bridges clinical care, education, and research to advance the science of healthy aging.
Castle Connolly Top Doctors are nominated by peer physicians and selected by the physician-led Castle Connolly research team based on criteria including medical education, training, hospital appointments, and disciplinary histories. Doctors do not and cannot pay to be selected.
