Meet our Team
Dr. Chris Renna
Dr. Renna is an esteemed alumnus of the University of Texas and the University of North Texas Health Science Center where he 
graduated cum laude with a medical degree. His medical journey advanced with a residency in family medicine, during which he realized a gap in the system: medical school was proficient at equipping doctors with the tools to identify disease, but fell short of educating them on how to foster overall health.
Recognizing this, Dr. Renna set out on a mission to revolutionize the healthcare approach, resulting in the inception of LifeSpan Medicine. This avant-garde system specializes in disease prevention, symptom resolution, and health improvement, all structured around comprehensive medical evaluations. LifeSpan takes a personalized and intensive approach, including features such as round-the-clock access to medical teams and unparalleled follow-up procedures via a concierge support system.
Since opening LifeSpan medicine in 1992, Dr. Renna has maintained a small practice focused on optimal health with two rules.
Everything is about you.
Everything is about your health.
Over the years his passion and dedication to clients along with his unique approach has earned him a reputation as the nation’s premiere preventive medicine provider. He is a published author, popular public speaker and lecturer to audiences across the United States and abroad.
Dr. Olivia Lesslar
Hailing from Australia, Dr. Olivia is a distinguished medical practitioner deeply committed to preventative and integrative
medicine.
Dr. Lesslar adopts a comprehensive and personalized approach to clinical care, focusing on determining the root cause of problems unique to each patient. Her bespoke treatment programs span all modalities, shaped to suit the specific needs and goals of her patients, whether that’s risk reduction, managing chronic illnesses, or biohacking. She is noted for her compassionate and optimistic interaction with patients.
As a respected speaker on the international circuit, Dr. Lesslar has delivered insightful talks on a wide array of topics, including general health, phytochemicals, diabetes, atopy, mind-body connections, and cancer. She has lent her expertise to the Neuroimmunology Associates of New York and engaged in collaborative research on neurodegenerative diseases with the esteemed neurologist, Dr. Jay Lombard.
Dr. Lesslar received her MBBS from Bond University in Queensland, Australia, after earning an undergraduate degree in International Relations, triple majoring in French and diplomacy. She holds certificates in remedial therapies, such as herbal treatment, nutrition, and acupressure. Furthermore, she possesses an Advanced Certificate in Skin Cancer Medicine, demonstrating her diverse proficiency in the medical field.
Dr. Paris Kharbat
Dr. Kharbat is a renowned physician certified in both functional and family medicine. She embarked on her academic journey 
at Texas A&M University for her undergraduate degree and proceeded to earn her medical degree at the University of North Texas Health Science Center, culminating her education with a residency at UC Davis Medical Center/Mercy Methodist Hospital.
Launching her over two-decade-long medical career as the medical director of IHS in California, Dr. Kharbat eventually ventured into functional medicine. She spent a decade in private practice, refining her approach to patient care, focusing on health goals and prevention of health deterioration.
She subsequently joined the Cleveland Clinic, where she, in collaboration with the globally recognized Dr. Mark Hyman, instituted a pioneering functional medicine program. During her tenure, she underwent intensive training in fascial distortion modelTM (FDM) and frequency-specific microcurrent (FSM), subsequently leading the development of a Functional Medicine Fellowship program and educating her peers on FDM.
Post-Cleveland Clinic, Dr. Kharbat led a private concierge practice, offering comprehensive preventative functional medicine programs to her clientele of executives and their families and colleagues, focusing on health optimization and longevity.
In 2023, she joined LifeSpan Medicine, dedicating her expertise to preventive functional medicine. She offers state-of-the-art comprehensive preventive longevity treatments and root cause functional medicine, fostering optimal health and functionality.
Dr. Kharbat is a distinguished member of various professional bodies, including the AOA, ABOIM, IFM, AAFP, ABFM. Her array of expertise and training encompass areas such as cognitive decline, advanced cardiometabolic practice, environmental health, gastrointestinal/microbiome health, hormone balancing, and immune support.
Dr. Moshe Ben-Roohi
Dr. Moshe Ben-Roohi stands out in the medical field for his expertise in advanced non-surgical orthopedics and regenerative
treatments, catering to cases such as sports injuries, degenerative joint diseases, and spinal conditions. His proficiency lies in addressing challenging scenarios, often aiding clients who have had little success with other treatments.
With dual board certifications in Physical Medicine and Rehabilitation (PM&R) and Pain Medicine, Dr. Ben-Roohi brings a well-rounded perspective to his practice. His medical journey began at Tel-Aviv University’s Sackler School of Medicine and led to a residency at NYU Medical Center and Hospital for Joint Diseases, where he held the role of Chief Resident. His academic pursuit further advanced with a fellowship in Interventional Spine and Sports Medicine.
Remaining engaged in academic medicine, Dr. Ben-Roohi continues to contribute to ongoing research and has an impressive record of publications in PM&R and various peer-reviewed journals. As a distinguished speaker, his areas of focus include Sports Medicine, Pain Management, and Molecular Orthopedics.
Dr. Ben-Roohi’s professional affiliations are extensive, including the American Medical Society for Sports Medicine (AMSSM), North American Spine Society (NASS), International Spine Intervention Society (ISIS), International Cellular Medicine Society (ICMS), American Academy of Orthopedic Medicine (AAOM), Institute for Functional Medicine (IFM), and the American Academy of Physical Medicine and Rehabilitation (AAPMR).
Dr. Jared Greenberg
Dr. Jared Greenberg is a highly regarded expert in the field of regenerative and non-surgical orthopedics, and his expertise in 
spine medicine is widely recognized among his peers. He is board-certified in PM&R and is a distinguished fellow of the American Academy of Physical Medicine and Rehabilitation. Throughout his career, he has successfully executed over 12,000 spine, joint, and bursa injection procedures, skillfully employing leading-edge technologies like fluoroscopic X-ray or ultrasound for enhanced accuracy.
His medical journey commenced at the University of Pennsylvania in Philadelphia, where he earned his MD degree. He embarked on an Orthopedic Surgery residency at the University of Wisconsin, Madison, during which he discovered a greater interest in non-surgical interventions for musculoskeletal conditions over surgical ones. Consequently, in 2006, Dr. Greenberg pursued a second residency, in Physical Medicine and Rehabilitation (PM&R), at the Hospital of the University of Pennsylvania. Completing the program in 2009, he notably served two consecutive years as Chief Resident.
Continuing his professional growth, Dr. Greenberg pursued subspecialty training as an Interventional Spine Fellow and Clinical Lecturer in the PM&R Spine Program at the University of Michigan Health System in Ann Arbor. He was also appointed as a National Board Examiner by the American Board of Physical Medicine and Rehabilitation, affirming his standing in the field.
Dr. Mary Caire
Dr. Caire’s medical journey began at LSU Medical School, New Orleans, from where she graduated in 1997. She completed a
dual residency in Physical Medicine and Rehabilitation (PM&R) and Internal Medicine in 2002, serving as the chief resident in her final year. Her board certification in PM&R was further complemented by a fellowship in Metabolic Medicine and Anti-Aging and Regenerative Medicine. She received additional board certification through the Metabolic Medical Institute at George Washington University School of Medicine and the American Academy of Anti-Aging and Regenerative Medicine.
In addition to her clinical responsibilities, Dr. Caire has held the position of President of the Wise County Medical Society and serves on the Texas State Medical Board Political Action Committee.
Her background in traditional allopathic medicine bolsters her specialization in functional medicine. Dr. Caire is an advocate for a holistic approach to health preservation, chronic illness prevention, and treatment. By leveraging advanced testing, she provides individualized comprehensive preventive plans focusing on nutrition, exercise, stress management, DNA-informed precision medicine, digestive health, and hormonal balancing. Her aim is to improve both short-term and long-term health by understanding each individual’s unique DNA, applying the science of epigenetics, and actively managing each detail of health.
Dr. Caire offers Comprehensive Executive health programs and Regenerative Sports Medicine treatments for joint and back issues to all LifeSpan clients.
A published author and noted speaker, Dr. Caire has delivered lectures both locally and nationally on various medical topics. These include precision medicine, addiction recovery, pain management, the use of big data in medicine, and DNA-informed medicine, among others. Her recent appearances include TEDx Turtle Creek and Hope For Tomorrow on Texas47 TV.
Nicole Visnic, MS, CCN
Nicole Visnic, as the Director of Nutrition for LifeSpan Medicine, brings a wealth of experience as a seasoned clinical 
nutritionist. Her proven ability to help clients reach their health and performance objectives has resulted in successful work with thousands of individuals on various issues, from body composition optimization to addressing health concerns such as fatigue and digestive problems. Nicole leverages personalized nutrition and lifestyle plans alongside innovative motivational strategies to ensure her clients commit to their programs and achieve optimal well-being.
Her professional journey has also seen her working closely with professional athletes from major leagues including the NFL, NBA, and MLB. Furthermore, she has provided nutritional guidance to athletes preparing for the Olympics. Her nutritional approach is tailored to ensure these high-performing individuals remain robust, resilient, and healthy, even under the pressure of rigorous training regimes.
Nicole holds a Bachelor’s Degree in Health Education from Winona State University and a Master’s Degree in Human Nutrition from the University of Bridgeport. Furthermore, she is a Certified Clinical Nutritionist, underpinning her vast practical experience with robust academic credentials.
Rachel Swanson, MS, RD
Rachel Swanson is a prominent nutritionist at LifeSpan Medicine, where she specializes in personalized nutrition programs
aimed at promoting optimum health, facilitating detoxification, encouraging weight loss, and optimizing performance and physical functionality. She earned her master’s degree in nutrition and her registered dietetic degree from NYU. Rachel’s noteworthy career commenced with the New England Patriots, where she developed team nutrition programs to enhance player health and team performance. Subsequently, she established a private practice, providing nutrition consulting for various organizations and projects, including Harvard, several nutraceutical companies, and private physicians.
Throughout her career, Rachel has served a diverse clientele, ranging from celebrities and professional athletes to business professionals and families of all ages. Her experience in dietetics and private practice has equipped her with expertise in addressing a wide array of health issues and designing nutritional programs to enhance health, prevent diseases, or manage conditions such as cardiovascular disease, diabetes, and gastrointestinal health. These programs also focus on weight management, anti-inflammatory diets, chronic disease prevention, skincare/anti-aging, and sports nutrition.
Passionate about her work, Rachel is wholly dedicated to helping each client achieve their health goals. Her current practice revolves around nutrition counseling, custom program creation, and nutritional education. As a renowned speaker, she has contributed to various media platforms and events, including TechCrunch, FounderMade, Huffington Post, and Dr Oz. Rachel is also a member of numerous professional organizations, such as the California Academy of Nutrition and Dietetics, Dietitian in Integrative and Functional Medicine, and the American College of Sports Medicine.
Call our Los Angeles Painrelief Clinic team today at (424) 728-5607 to make an appointment!