- Researchers conducted a systematic review of randomized controlled trials of a selection of weight loss supplements and alternative therapies.
- They found no high-quality evidence of the efficacy of any of the products reviewed.
- An accompanying opinion piece calls for closer scrutiny of the supplement industry and its role in promoting “misleading claims” about products.
- The Council for Responsible Nutrition, which represents the supplement industry, has questioned the validity of this latest research.
Among adults in the United States trying to maintain a moderate weight,
But, according to a new review, high-quality evidence of the benefits of many weight loss products and alternative therapies is currently lacking.
The systematic review of randomized controlled clinical trials — the gold standard of clinical research — appears in the journal
“Our findings are important for clinicians, researchers, and industry alike, as they suggest the need for rigorous evaluation of products for weight loss,” says corresponding author John Batsis, M.D., of the University of North Carolina School of Medicine, Chapel Hill.
“Only then can we produce data that allows clinicians to provide input and advice with a higher degree of certainty to our patients,” he adds.
The condition also has associations with an increased risk of diabetes, heart disease, cancer, and premature death.
People often struggle to lose weight; due to either a lack of effectiveness of Food and Drug Administration (FDA)-approved treatments or no access to healthcare professionals who can provide anti-obesity therapy.
The researchers write that many people turn to nonprescription weight loss supplements in the belief that they are “natural” or “clinically proven.” Consumers may even believe these products are as safe as FDA-approved drugs.
In addition, the scientists say that healthcare professionals have incomplete information about the scientific claims made by the promoters of such therapies.
The researchers reviewed randomized controlled trials that evaluated the efficacy of 14 dietary supplements, therapies, or both, including:
- green tea
- ephedra or caffeine
- guar gum
- calcium-vitamin D supplements
- chocolate or cocoa
- mind-body therapies
Out of a total of 315 trials, they judged 52 to have a low
Of these, 16 reported statistically significant weight reduction throughout the trial, ranging from 0.3 to 4.93 kilograms.
However, the authors write that these reductions were not “clinically significant.”
“An outcome can be statistically significant without being clinically significant,” Prof. Batsis told Medical News Today.
He said clinical guidelines consider a weight loss of more than 5% to be clinically significant.
“During our review of supplement studies, in the rare cases where people did lose weight, they did not drop enough pounds to make a positive impact on their health,” he said.
In their paper, the researchers conclude:
“Despite there being a number of studies evaluating dietary supplements and alternative therapies for weight loss, this review does not support strong, high-quality evidence of the efficacy of any of the products.”
In 1994, the
Under the Act,
In a strongly worded
The authors 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.”
Steve Mister, president and CEO of the Council for Responsible Nutrition (CRN), which represents the supplement industry, challenged the study’s validity. CRN is “is the leading trade association representing dietary supplement and functional food manufacturers and ingredient suppliers.”
In a statement provided to MNT, he questioned the inclusion of acupuncture, mind-body interventions, and chocolate, among others, in what he described as a “hodgepodge” of products and therapies.
He added that manufacturers do not market vitamin D and calcium for weight loss.
“There are many safe, beneficial weight management dietary supplements on the market with research support in this category, along with supplements that help fill nutrient gaps for consumers who do not get all the nutrients they need from food alone, especially when they are limiting calories or engaging in strenuous exercise,” he said.
“The recent review only covers a handful of ingredients in this area and should not diminish the supportive role these products play for consumers’ weight management programs,” he added.
However, he agreed with the scientists’ call for more research, adding that industry and academia should strengthen their research collaborations.