SILVER SPRING, Md.-- Although Americans spend billions on them, published research shows a lack of strong evidence that dietary supplements and alternative therapies help adults lose weight, according to a new study published in Obesity, the flagship journal of The Obesity Society (TOS).
There are hundreds of weight-loss supplements like green tea extract, chitosan, guar gum and conjugated linoleic acid, and an estimated 34% of Americans who are trying to lose weight have used one.
For the study, researchers completed a comprehensive review of 315 existing clinical trials of weight loss supplements and therapies, and most of the studies showed the supplements did not produce weight loss among users.
"Our findings are important for clinicians, researchers, and industry alike as they suggest the need for rigorous evaluation of products for weight loss," said corresponding author John Batsis, MD, associate professor in the Division of Geriatric Medicine at the University of North Carolina (UNC) School of Medicine, and in the Department of Nutrition at the UNC Gillings School of Global Public Health. "Only then can we produce data that allows clinicians to provide input and advice with a higher degree of certainty to our patients."
The evaluation should also be collaborative as the supplement industry and academics work together to design high-quality clinical trials of weight loss supplements, Batsis added.
The paper's authors explain that patients often struggle to lose or maintain weight either because of a lack of efficacy of existing Federal Drug Administration (FDA)-approved therapies or a lack of access to healthcare professionals who provide treatments for obesity.
Even though the National Institutes of Health's Office of Dietary Supplements has advanced the science of dietary supplements by evaluating information, and stimulating and supporting research, members of TOS decided it was important to evaluate and perform a qualitative synthesis of non-FDA therapies to provide scientific evidence to guide its membership.
Researchers conducted a systematic literature review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to evaluate the efficacy of dietary supplements and alternative therapies for weight loss in participants aged 18 and older. Searches of Medline (Pubmed), Cochrane Library, Web of Science, CINAHL and Embase (Ovid) were performed.
Researchers focused on 315 peer-reviewed randomized-controlled trials and analyzed them for risk of bias. Results classified 52 studies as low risk of bias and sufficient to support efficacy. Of these, 16 studies demonstrated significant pre/post intergroup differences in weight compared with placebos. In these methodologically distinct studies, the weight loss ranged widely from 0.3 to 4.93 kg.
In a perspective written by members of TOS's Clinical Committee led by Srividya Kidambi, MD, MS, Division of Endocrinology and Molecular Medicine, Medical College of Wisconsin in Milwaukee who also co-authored the paper, members recommend to clinicians to consider the lack of evidence of non-FDA-approved dietary supplements and therapies and guide their patients toward tested weight-management approaches. "Public and private entities should provide adequate resources for obesity management. We call on regulatory authorities to critically examine the dietary supplement industry, including their role in promoting misleading claims and marketing products that have the potential to harm patients," the authors write in the paper.
Other authors of the study include John Apolzan, Steven Heymsfield and Abishek Stanley of the Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, La.; Pamela Bagley, Heather Blunt and Ryan Shean of Dartmouth College in Hanover, N.H.; Vidita Divan of Stormont Vail Health in Topeka, Kan.; Sonia Gill of the University of California, Davis, School of Medicine, Sacramento, Calif.; Angela Golden of the NP Obesity Treatment Clinic, Flagstaff, Ariz.; Shalini Gundumraj of Cornell University, Ithaca, N.Y.; Scott Kahan of the National Center for Weight and Wellness, George Washington University Milken Institute School of Public Health in Washington, DC; Katherine Kopatsis of George Washington University, Washington, DC; Ava Port, Division of Endocrinology, Diabetes and Nutrition, University of Maryland School of Medicine, Baltimore, Md.; Elizabeth Parks, Division of Gastroenterology, Hepatology and Nutrition, The Children's Hospital of Philadelphia and The Healthy Weight Program, Perelman Medical Center, University of Pennsylvania, The Children's Hospital of Philadelphia; Clifford Reilly of The Robert Larner, M.D. College of Medicine at the University of Vermont, Burlington; Domenica Rubino of the Washington Center for Weight Management and Research, Arlington, Va.; Katherine Saunders and Beverly Tchang, Division of Endocrinology, Diabetes and Metabolism, Weill Cornell Medicine, Comprehensive Weight Control Center in New York, N.Y.; Luai Tabaza of Albert Einstein Medical Center in Philadelphia, Pa.; and Shivani Gundumraj of A.T. Still University School of Osteopathic Medicine, Mesa, Ariz.
The paper, titled "A Systematic Review of Dietary Supplements and Alternative Therapies for Weight Loss", will be published in the July 2021 print issue. A perspective titled "Dietary Supplements and Alternative Therapies for Obesity: A Perspective from The Obesity Society's Clinical Committee" will accompany the paper.
Batsis' research reported in this publication was supported in part by the National Institute on Aging of the National Institutes of Health (K23AG051681). He also reports equity in SynchroHealth LLC, a remote monitoring startup. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Apolzan has received funding from a food company to investigate topics from this manuscript. There was no funding from The Obesity Society for the development of the work from this manuscript. Golden reports consulting with Novo Nordisk and Unjury. Heymsfield reports personal fees from Medifast. Rubino reports consulting and speaking fees for Novo Nordisk and AstraZeneca. Saunders has a relationship with Intellihealth Inc. Kidambi is the medical director for TOPS Center for Metabolic Health at the Medical College of Wisconsin, which is supported by TOPS, Inc.
The Obesity Society (TOS) is the leading organization of scientists and health professionals devoted to understanding and reversing the epidemic of obesity and its adverse health, economic and societal effects. Combining the perspective of researchers, clinicians, policymakers and patients, TOS promotes innovative research, education and evidence-based clinical care to improve the health and well-being of all people with obesity. For more information, visit http://www.obesity.org.