77
Food and Drug Administration, Center for Food Safety and Applied Nutrition. FDA’s implementation of
“qualified health claims”: questions and answers. May 12, 2006. (Accessed January 3, 2008, at
http://www.cfsan.fda.gov/-dms/qhcqagui.html).
78
Food and Drug Administration, Center for Food Safety and Applied Nutrition. Interim evidence-based ranking
system for scientific data. July 10, 2003. (Accessed January 3, 2008, at
h9ttp://www.cfsan.fda.gov/-dms/hclmgui4.htm1).
Id.
80
Dwyer JT, Allison DB, Coates PM. Dietary supplements in weight reduction. J Am Diet Assoc 2005;105(5 Suppl
1):S80-6. (Exh. 34).
reported that many weight loss supplements have never been the subject of randomized human
clinical studies and “no weight loss supplements meet criteria for recommended use.”” In still
another study, investigators from the Universities of Exeter and Plymouth declared that there “is
little convincing evidence that any dietary supplement is effective in reducing body weight. ,82
These conclusions were further confirmed by the School of Pharmacy at Creighton University.g3
These systematic reviews are particularly telling since they focused on the principal
“active ingredients” that are included in weight loss supplements. While there are myriad weight
loss products, most of these products actually fall into a few discrete categories based on their
purported “active” ingredient or the mechanism of action through which these ingredients .
supposedly help individuals lose weight. Thus, weight loss supplements have been classified
based on whether they purportedly: (1) increase energy expenditure; (2) modulate carbohydrate
metabolism; (3) increase satiety or suppress appetite; (4) increase fat oxidation or reduce fat
synthesis; or (5) block dietary fat absorption. 84 The foregoing systematic studies focused on the
major ingredients in each of these categories of weight loss supplements. This is confirmed by a
recent consumer research survey and an audit of retail outlets identifying the particular types of
weight loss supplements typically purchased by consumers. 85
2. There Is Currently No Credible Scientific Evidence That Would Support a
Qualified Health Claim for Any Ingredient in Any of the Five Categories of
Weight Loss Supplements
It is beyond the scope of this petition to review all of the data that purportedly support the
efficacy of weight loss supplements from these five categories. Nonetheless, the summary that
follows makes clear that currently available data would not support even the weakest of the
qualified health claims for any weight loss supplement for use in an overweight population.g6
There are conflicting results among the studies for each ingredient while, in most cases, there are
studies of high quality that did not detect any effect on weight loss from these supplements.
Moreover, many of the studies that purportedly support the efficacy of weight loss supplements
may not be relied upon since the products actually contain a combination or amalgam of
different ingredients. Furthermore, many of the studies involved short terms and small
population sizes and, significantly, do not distinguish between overweight individuals and those
whose BMI makes them obese. That is important because, to the extent that a qualified health
81
Saper RB, Eisenberg DM, Phillips RS. Common dietary supplements for weight loss. Am Fam Physician
2004;70:1731-8. (Exh. 35).
82
Pittler MH, Ernst E. Dietary supplements for body-weight reduction: a systematic review. Am J Clin Nutr
2004;79:529-36. (Exh. 36).
83
Lenz TL, Hamilton WR. Supplemental products used for weight loss. J Am Pharm Assoc 2004;44:59-67. (Exh.
37).
84
DeBusk RM. A critical review of the literature on weight loss supplements. Integr Med Consult 2001;3:30-1.
(Exh. 38).
85
Blanck HM, Serdula MK, Gillespie C, et al. Use of nonprescription dietary supplements for weight loss is
common among Americans. J Am Diet Assoc 2007;107:441-7. (Exh. 28); Sharpe PA, Granner ML, Conway JM; et
al. Availability of weight-loss supplements: results of an audit of retail outlets in a Southeastern city. J Am Diet
Assoc 2006;106:2045-51. (Exh. 39).
$6 Many weight loss supplements are distributed as combinations containing various ingredients. There also does
not appear to be any credible scientific data supporting the efficacy of such combination products.
claim could be made, it would need to be based solely on data involving overweight – not obese
– individuals. 87 Finally, to the extent that any evidence exists at all, it would be even weaker if it
were extrapolated to support a disease risk reduction claim – that is, the subject of a permissible
health claim.
A brief description follows of the particular findings involving each of the principal
ingredients in each category of weight loss supplement:
(1) Supplements that Increase Energy Expenditure
Bitter Orange: Also known as Zhi shi, bitter orange is derived from an Asian tree
species (Citrus aurantium) and is widely regarded as a substitute for ephedra. The
active ingredient in bitter orange is believed to be synephrine – a sympathomimetic
amine that is structurally similar to epinephrine. There is “little evidence” that bitter.
orange is effective in weight loss. 88 In fact, a randomized, placebo controlled trial
found no benefit for weight loss from bitter orange. 89 On the other hand, bitter orange
and another supplement in the same category (Guarana) may have adverse effects
similar to ephedra, including increased heart rate, blood pressure, and the risk of cardiac
complications. 90
(2) Supplements that Modulate Carbohydrate Metabolism
Chromium: Chromium picolinate is a naturally occurring derivative of tryptophan that
is claimed to promote weight loss by optimizing insulin signaling. “Insufficient
evidence exists” to support the effectiveness of chromium, and many studies yielded
“inconsistent results,” were “poorly designed,” and reported benefits that were refuted
by other reports.91 The results of other studies, including three randomized clinical
trials, did not show any differences in weight loss between treatment and control
groups. 92 Moreover, to the extent that any studies have shown slight weight loss from
87
While qualified health claims may speak to a substance’s ability to reduce the risk of disease, they may not
characterize a substance as treatment for the disease itself. See Food and Drug Administration, Center for Food
Safety and Applied Nutrition. FDA’s implementation of “qualified health claims”: questions and- answers. May 12,
2006. (Accessed January 3, 2008, at http://www.cfsan.fda.gov/-dms/qhcqagui.html). To the extent that any
scientific studies demonstrate the efficacy of particular ingredients for weight loss, then, they are relevant to the
qualified health claims analysis only if such studies measured the effect of ingredients on overweight subjects (i.e.,
individuals at risk for obesity), rather than individuals who were already obese.
gg Fugh-Berman A, Myers A. Citrus aurantium, an ingredient of dietary supplements marketed for weight loss:
current status of clinical and basic research. Expert Biol Med 2004;229:698-704. (Exh. 40).
89
Bent S, et al. Safety and efficacy of citrus aurantium for weight loss. Am J Cardiol 2004;94:1359-61. (Exh. 41).
90
Hess AM, Sullivan DL. Potential for toxicity with use of bitter orange and guarana for weight loss. Ann
Pharmacother 2005;39:574-5. (Exh. 42); Bouchard NC, et al. Ischemic stroke associated with use of an ephedra-free
dietary supplement containing synephrine. Mayo Clin Proc 2005;80:541-5. (Exh. 43); Nykamp D, Fackih MN,
Comptom AL. Possible association of acute lateral-wall myocardial infarction and bitter orange supplement. Ann
Pharmacother 2004;38:812-6. (Exh. 44).
91
Lukaski HC. Chromium as a supplement. Annu Rev Nutr 1999;19:279-302; Lenz TL, Hamilton WR.
Supplemental products used for weight loss. J Am Pharm Assoc 2004;44:59-67. (Exh. 37).
92
Bahadori B, Waliner S, Schneider H, Wascher TC, Toplak H. [Effect of chromium yeast and chromium picolinate
on body composition of obese, non-diabetic patients during and after a formula diet]. Acta Med Austriaca
chromium supplements, the observed effect was found “not clinically meaningful. 03
Therefore, as one report recently concluded, there are “no independent effects of
–
chromium picolinate supplementation on body weight or composition. “94
(3) Supplements that Increase Satiety or Suppress Appetite
Guar Gum: This dietary fiber is derived from the Indian cluster bean (Cyamopsis
tetragonolobus). Soluble fiber is believed to absorb water within the gut, thereby
causing increased satiety and lower caloric intake. The efficacy of this supplement was
assessed in a meta-analysis of 20 double-blind, placebo-controlled randomized clinical
trials. That meta-analysis indicated that guar gum is “not effective” in reducing body
weight.95 The consistency of the results among the individual trials confirmed the
overall conclusion of this meta-analysis. 96 Other studies have reported adverse
gastrointestinal events associated with guar gum. 97
Hoodia: Much attention has recently been focused on P57, a steroidal glycoside that is
extracted from the South African plant species, Hoodia gordonii. P57 is believed to
cause neurons within the satiety center of the hypothalamus to fire rapidly and thereby
suppress appetite. While certain animal studies involving P57 have been published,
there does not appear to be any publications in peer-reviewed journals involving human
trials with Hoodia extract. 98 As a result, there is no credible scientific support for the
efficacy of weight loss supplements containing Hoodia extracts.
(4) Supplements that Increase Fat Oxidation or Reduce Fat Synthesis
Garcinia: Hydroxycitric acid (“HCA”) is contained within extracts of the fruit rind of
Garcinia cambogia, a tree species native to India. HCA has been shown to inhibit
citrate cleavage enzyme and suppress fatty acid synthesis. Nevertheless, clinical data to
suggest that HCA may help in weight loss are “inconsistent” and most of the clinical
1997;24:185-7. German. (Exh. 45); Pasman WJ, Westerterp-Plantenga MS, Saris WHM. The effectiveness of long-
term supplementation of carbohydrate, chromium, fibre and caffeine on weight maintenance. Int J Obes
1997;21:1143-51. (Exh. 46); Crawford V, Scheckenbach It, Preuss HG. Effects of niacin-bound chromium
supplementation on body composition in overweight African-American women. Diabetes Obes Metab 1999;1:331-
7. (Exh. 47).
93
Pittler MH, Ernst E. Dietary supplements for body-weight reduction: a systematic review. Am J Clin Nutr
2004;79:529-36. (Exh. 36).
94
Lukaski HC, et al. Chromium picolinate supplementation in women: effects on body weight, composition, and
iron status. Nutrition 2007;23:187-95. (Exh. 48).
95
Pittler MH, Ernst E. Guar gum for body weight reduction, meta-analysis of randomized trials. Am J Med
2001;110:724-30. (Exh. 49).
96
Pittler MH, Ernst E. Dietary supplements for body-weight reduction: a systematic review. Am J Clin Nutr
2004;79:529-36. (Exh. 36).
97 Dwyer JT, Allison DB, Coates PM. Dietary supplements in weight reduction. J Am Diet Assoc 2005;105(5 Suppl
1):S80-6. (Exh. 34).
98Lee RL, Balick MJ. Indigenous use of Hoodia gordonii and appetite suppression. Explore 2007;3:404-6. (Exh.
50).
studies are “confounded by methodological flaws.”99 Where there has been a
randomized, double blind clinical trial involving HCA, it found no significantly greater
weight loss in the treatment group than in the placebo group. 100
Conjugated Linoleic Acid (“CLA”): CLA is a group of linoleic acid derivatives
produced by bacteria in the gut of ruminant animals. This compound is believed to
inhibit lipoprotein lipase, an enzyme that breaks down fat for absorption. Data from
human studies involving CLA are “equivocal and uncompelling.”1° Several studies
have found no changes in body weight or BMI.1°2 Moreover, based on an analysis of
the results from 13 randomized, controlled trials, investigators reported that there is
little evidence to suggest that CLA helps reduce body weight. 103 The authors of this
study also reported that CLA may promote liver hypertrophy and insulin resistance, and
therefore, may have adverse effects.

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