More than two-thirds of adults and almost one-third of children and adolescents in the United States are overweight or obese.1 Exercise and dieting typically start with a New Year’s Resolution, but often do not last for long. Customers are instead seeking a more acceptable and manageable alternative.
Americans spend about US$2.1 billion a year on weight management dietary supplements.2 Like other dietary supplements, weight management supplements are regulated by FDA; therefore, supplement manufacturers are responsible for ensuring their products are safe, and their label claims are truthful and not misleading.
Weight management dietary supplements are complex mixtures, and as a result, their ingredients should be validated for efficacy for a truthful claim substantiation.
Several ingredients are effective in potentially reducing body weight and waist circumference, according to clinical trials. Since the mechanisms of action are established, suitable biological assays can validate the efficacy of an ingredient coming from different suppliers. On the contrary, other ingredients marketed for weight management (including beta-glucans, calcium, capsaicin, guar gum, hoodia, vitamin D or yohimbine, among others) were ineffective in reducing body weight in clinical trials.3
Effective weight management ingredients often have a modest, but significant effect on body weight as confirmed in clinical trials. Moreover, validation of their efficacy in biological assays is suggested.
Caffeine can be used as an additive to other ingredients in weight management supplements or may be present naturally in herbal products. A clinical trial with overweight or obese participants demonstrated significant weight reduction and fat reduction (mean weight loss 5.3 kg), compared to a placebo group (2.6 kg) with a supplement containing caffeine and ephedrine.4 The bioassays validating the activity of caffeine might utilize the inhibition of fat accumulation in fat cells.
In addition to the activity of caffeine, weight loss is caused by major ingredients in the green coffee bean, such as chlorogenic acids. Chlorogenic acids regulate the differentiation of fat cells. A clinical trial demonstrated green coffee extract moderately, but significantly, reduced body weight and fat accumulation (mean weight loss of 2.47 kg more than placebo) in overweight subjects.5 Bioassays evaluating the activity of green coffee bean extract employed hypolipidemic effects in fat cells.
The active components of green tea associated with weight management are catechins, primarily epigallocatechin gallate (EGCG) and caffeine. A meta-analysis of several, randomized, controlled trials found a combination of EGCG with caffeine for 12 to 13 weeks resulted in mean reduction of 1.31 kg of body weight compared to control groups.6 Since green tea extracts contain dissimilar amounts of EGCG and catechins, bioassays evaluating their efficacy need to be used.
African mango (Irvingia gabonensis) is a fruit seed extract that has decreased body weight, waist circumference and body fat percentage in clinical trials. Three trials reported a statistically significant reduction in body weight compared with placebo (12.8 kg versus 0.7 kg; 4.1 kg versus 0.1 kg; 11.9 kg versus 2.1 kg).7 This weight loss effect was probably induced by inhibiting adipogenesis. The activity of African mango seed extract might use a bioassay evaluating the differentiation of fat cells.
Extracts of a white kidney bean (Phaseolus vulgaris) are used as active compounds in several weight management dietary supplements. They are marketed as carbohydrate- or starch-absorption blockers. One randomized, double-blind clinical trial with mildly overweight women demonstrated dried aqueous extract of Phaseolus vulgaris significantly reduced body weight (with a mean weight loss of 2.93 kg) when compared to placebo (mean weight loss of 0.35 kg).8 Another recent trial with overweight and obese men and women showed Phaseolus vulgaris also significantly reduced body weight and body fat.9 The weight management activity of white kidney bean extract is caused by an alpha-amylase inhibitor. Therefore, a bioassay evaluating alpha-amylase will validate the activity of specific Phaseolus vulgaris extracts.
Other dietary supplements, including chitosan, chromium, conjugated linoleic acid (CLA) or pyruvate, demonstrated only minimal, clinically insignificant effects on body weight.
In summary, several clinical trials with supplements containing caffeine, green coffee bean extract, green tea extract, African mango extract and white kidney bean extract demonstrated significant reduction of body weight and fat. Clinical trials may substantiate efficacy claims of these extracts on the weight management dietary supplement label. However, the proper validation of efficacy must be performed. Chemical analysis of an extract is usually focused on the identification of the main compound(s), which is important for the characterization of the extract, while efficacy (biological activity) depends on the full composition of the extract. Origin of the starting extraction material, cultivating conditions, and storage and extraction procedures will impact the quality corresponding to the efficacy of the specific extract. Since these conditions are different among producers, the extracts of the “same” chemically analyzed compound(s) will have dissimilar efficacy.
DSTest Labs recently evaluated several green tea extracts containing high amounts of EGCG and other catechins for their efficacy. Not surprisingly, some of the extracts had miniscule biological activity, whereas others demonstrated strong efficiency in the bioassay.
Obviously, the best high-quality weight management supplements containing truthful label claims must contain highly efficient extracts. In other words, only proper testing will get rid of the “fake” dietary supplements in the industry.
Daniel Sliva, Ph.D., CEO & founder, DSTest Labs (dstest-lab.com), is a senior investigator at Indiana University Health, and an adjunct associate professor at the Indiana University School of Medicine. He has master’s degrees in food and biochemical technology, as well as biochemistry, and a doctoral degree in molecular biology and genetics. Sliva also completed postdoctoral studies at the department of medical nutrition, Karolinska Institute, Sweden, and at the Indiana University School of Medicine, Indianapolis. He founded DSTest Laboratories at Purdue Research Park in 2014 for evaluating and standardizing efficacy of ingredients, nutraceuticals and dietary supplements. In addition to authoring more than 82 peer-reviewed papers and three book chapters, he is an international speaker.
- Ogden CL et al. “Prevalence of obesity and trends in body mass index among US children and adolescents, 1999-2010.” JAMA. 2012;307:483-90.
- “A race of results.” Nutr Bus J. 2016;21:3-7.
- National Institute of Health. “Office of Dietary Supplements. Dietary Supplements for weight management.” 2017.
- Boozer C et al. “Herbal ephedra/caffeine for weight management: a 6-month randomized safety and efficacy trial.” Int J Obes Relat Metab Disord. 2002;26:593-604.
- Onakpoya I, Terry R, Ernst E. “The use of green coffee extract as a weight management supplement: a systematic review and meta-analysis of randomised clinical trials.” Gastroenterol Res Pract. 2011;2011.
- Hursel R, Viechtbauer W, Westerterp-Plantenga MS. “The effects of green tea on weight management and weight maintenance: a meta-analysis.” Int J Obes (Lond). 2009;33:956-61.
- Onakpoya I et al. “The efficacy of Irvingia gabonensis supplementation in the management of overweight and obesity: a systematic review of randomized controlled trials.” J Diet Suppl. 2013;10:29-38.
- Celleno L et al. “A dietary supplement containing standardized Phaseolus vulgaris extract influences body composition of overweight men and women.” Int J Med Sci. 2007;4:45-52.
- Grube B et al. “Weight reduction and maintenance with IQP-PV-101: a 12-week randomized controlled study with a 24-week open label period.” Obesity. 2014;22:645-51.