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Overweight and obesity are growing health problems in the United States, with approximately one-third of adults being obese and more than one-third are overweight. Many overweight individuals turn to dietary and herbal supplements for weight loss, and millions of dollars are spent on these products. However, there are concerns about the safety and efficacy of many supplements. Supplements are believed to help weight loss by several mechanisms of action, including increasing energy expenditure, increasing satiety, increasing fat oxidation, blocking dietary fat absorption, modulating carbohydrate metabolism, increasing fat excretion, increasing water elimination, and enhancing mood. This topic is changing rapidly, and this review gives a perspective of the current state of the evidence on selected dietary and herbal supplements and combination products. Many supplements have not been studied in randomized controlled trials and require more research to determine efficacy. Nutrition and healthcare professionals need to discuss use of dietary supplements with patients and report any adverse events to the Food and Drug Administration. Additional regulations on production, sales, and marketing of these supplements would be needed.
Content may be subject to copyright.
Top Clin Nutr
Vol. 25, No. 2, pp. 136–150
Copyright c
2010 Wolters Kluwer Health |Lippincott Williams & Wilkins
Herbal and Dietary
Supplements for Weight Loss
Raghda Ghussen Alraei, MS, RD, CDN
Overweight and obesity are growing health problems in the United States, with approximately one-
third of adults being obese and more than one-third are overweight. Many overweight individuals
turn to dietary and herbal supplements for weight loss, and millions of dollars are spent on these
products. However, there are concerns about the safety and efficacy of many supplements. Sup-
plements are believed to help weight loss by several mechanisms of action, including increasing
energy expenditure, increasing satiety, increasing fat oxidation, blocking dietary fat absorption,
modulating carbohydrate metabolism, increasing fat excretion, increasing water elimination, and
enhancing mood. This topic is changing rapidly, and this review gives a perspective of the cur-
rent state of the evidence on selected dietary and herbal supplements and combination products.
Many supplements have not been studied in randomized controlled trials and require more re-
search to determine efficacy. Nutrition and healthcare professionals need to discuss use of dietary
supplements with patients and report any adverse events to the Food and Drug Administration.
Additional regulations on production, sales, and marketing of these supplements would be needed.
Key words: dietary supplements,herbal supplements,safety and efficacy,weight loss
OVERWEIGHT and obesity are growing
health problems in the United States,
with approximately one-third of adults being
considered obese and more than one-third
overweight.1Standard treatment of obesity
includes reducing energy intake and increas-
ing energy expenditure through exercise.
However, adherence to lifestyle changes and
exercise programs are generally poor.2For
this reason, many overweight individuals turn
to dietary and herbal supplements for weight
loss.2Since 1994, with the passing of the
Dietary Supplements Health Education Act,
Author Affiliations: Department of Nutrition
Sciences, School of Health Related Professions,
UMDNJ University of Medicine & Dentistry of New
Jersey, Newark; and Department of Health and
Nutrition Sciences, Brooklyn College, The City
University of New York, Brooklyn.
The author thanks Dr Jane Ziegler for her assistance
and continued support.
Corresponding Author: Raghda Ghussen Alraei, MS,
RD, CDN. Nutrition Services, 476 73rd St, Brooklyn, NY
11209 (
which enables manufacturers to market di-
etary and herbal products without proof
of efficacy and safety, as required for pre-
scription drugs, sales of supplements have
increased.3,4 With the availability of dietary
supplements on the market, Americans are
spending millions of dollars for weight loss
supplements. In 2002, for example, it was
estimated that $2 billion were spent on
weight loss products.5In a 2007 study, it
was estimated that 15.2% of American adults
(20.6% women and 9.7% men) had used di-
etary supplements for weight loss.6Many
supplements are labeled as “natural,” which
gives the consumers the impression that they
are safe.7However, there is concern about
the safety and efficacy of many dietary and
herbal supplements because they contain ac-
tive ingredients, which may interact with pre-
scription drugs, and can cause adverse ef-
fects. Evidence about the efficacy of many of
the supplements is inconclusive.7There are
more than 50 individual dietary supplements
and 125 combinations products listed in the
Natural Medicine Comprehensive Database as
Dietary and Herbal Supplements for Weight Loss 137
being used for weight loss. However, many of
the supplements have not been tested for effi-
cacy and safety or studied in randomized con-
trolled trials (RCTs).8
Claims on dietary and herbal supplements
attribute weight loss to several mechanisms
including the following8,9:
Increase of energy expenditure:
ephedra, caffeine, guarana, bitter or-
ange, yerba mat´
Increase in satiety: soluble fibers such as
guar gum, glucomannan, psyllium
Increase of fat oxidation: hydroxyc-
itric acid (HCA), green tea, conjugated
linoleic acid (CLA), fish oil, capsaicin,
Blocking of dietary fat absorption: chi-
Modulation of carbohydrate
metabolism: chromium
Increase of fat excretion: calcium
Increased water elimination: dandelion,
Enhancement of mood: St. John’s wort
This article examines some of the com-
monly used dietary and herbal supplements
and reviews the available evidence from
RCTs, systematic reviews, and meta-analyses
regarding their efficacy, safety, and drug inter-
actions. Some data are also obtained from the
Natural Medicine Comprehensive Database,
which was established in 1999, and is rec-
ognized as a valuable resource for evidence-
based information on the topic of herbs, di-
etary supplements, and drugs. Information
about ingredients in supplements is organized
in monographs that list their use, safety, ef-
fectiveness, action, adverse reactions, and in-
teractions with medications, other herbs, and
Ephedra sinica is an evergreen shrub that
is native to central Asia, with ephedrine,
or ephedra alkaloids,8being the active in-
gredients in the plant.1It is also called
ma huang and has been used in tradi-
tional Chinese medicine with a combina-
tion of other herbs,3although its use for
weight loss is not part of traditional Chinese
medicine.7Ephedra alkaloids are powerful
central nervous system (CNS) stimulants and
sympathomimetic agents that cause cardiac
stimulation and vasoconstriction.11 Ephedra-
containing dietary supplements were widely
used in the mid-1990s until 2004 when the
sale of these supplements was banned in
the United States.7A recent systematic re-
view sponsored by the National Institutes of
Health concluded that ephedra use was as-
sociated with a modest but statistically sig-
nificant increase in weight loss (0.9 kg per
month) compared with a placebo over a
short period of time (<6 months).7How-
ever, these controlled studies reported that
ephedra use was associated with 2.2- to 3.6-
fold increase in odds of several adverse re-
actions such as gastrointestinal (GI), auto-
nomic, and psychiatric symptoms as com-
pared with controls.1,7 Long-term studies (>6
months) have not been conducted.7,8 Sev-
eral reported adverse events, which included
heart palpitation, GI symptoms, dizziness, in-
creased blood pressure, strokes, and psychi-
atric symptoms such as anxiety, and halluci-
nations, were associated with ephedra use.12
Some reports also linked ephedra use to per-
manent disability (13 reports) and death (10
reports).12 After the review of all the ad-
verse reaction reports, the Food and Drug Ad-
ministration (FDA) concluded that ephedra-
containing products should not be recom-
mended for weight loss because they pose a
risk for illness or injury; therefore, the supple-
ment sale was banned in 2004.7
Adverse drug-supplement interactions
can occur when ephedra is combined
with monoamine oxidase inhibitors, an-
tidepressants, medications containing
pseudoephedrine or ephedrine, and caffeine,
which can result in excessive CNS stimula-
tion. Adverse interactions can also occur with
medications used for the treatment of heart
disease, hypertension, depression, Parkinson
disease, asthma, or diabetes.11
Caffeine, guarana, and yerba mat´
Caffeine is a CNS stimulant8and is com-
monly consumed with coffee, tea, and soft
drinks. The scientific name of caffeine is 1,3,7-
trimethylxanthine.10 Caffeine use for weight
loss has been studied in combination with
ephedra and has been shown that the combi-
nation is effective in reducing weight in the
short term.10 In a double-blind RCT on 35
overweight subjects, 72 mg of ephedra and
240 mg of caffeine for 8 weeks caused a sig-
nificant decrease in body weight and body fat
in the study group compared with the control
group.13 Another RCT that tested an herbal
supplement containing 210 mg of ephedra
and 72 mg of caffeine overall for 12 weeks
found that the treatment group had a sig-
nificant decrease in mean body weight and
in the percentage of body fat.13 A more re-
cent RCT on a multinutrient supplement con-
taining a low dose of ephedra and caffeine
(40 mg of ephedra and 100 mg of caf-
feine), which was tested on 61 healthy,
overweight, postmenopausal women, found
that the treatment group lost significantly
more body weight (7.18 kg) and body fat
(5.33 kg) than controls.14 Adverse effects
reported from these studies included dry
mouth, insomnia, headaches, nervousness,
and palpitation.13,14 After the ban of ephedra,
many dietary supplements have been refor-
mulated and marketed as “ephedra free.”
One of these combination supplements is
a product called Hydroxycut, with caffeine
as the major ingredient. The recommended
dose provides 600 mg of caffeine (equiva-
lent to 6 cups of coffee) and it also contains
other ingredients including HCA, Gymnema
sylvestre, glucomannan, guarana, green tea
extracts (GTEs), and willow bark.15 One case
report showed the development of hyperten-
sive retinopathy in a previously healthy indi-
vidual associated with the use of this caffeine-
based product. It is not clear whether caffeine
alone was the causative agent, or whether
it worked with the other ingredients syn-
ergistically; however, it was presumed that
the causative agent had a sympathomimetic
effect.15 There are also reports that some stim-
ulant, ephedra-free products are associated
with hepatotoxicity, dysrhythmia, hyperten-
sion, and ischemic stroke.15
Guarana and yerba mat´
e are the botani-
cal sources of caffeine.8Guarana is extracted
from the seeds of Paullinia cupana, which
is a South American shrub native to the
Amazon.11,12 Guarana seeds contain 4% to
5% caffeine compared with coffee beans,
which contain 1% to 2% caffeine. In ad-
dition to its inclusion in dietary supple-
ments, guarana is added to many energy
drinks and bars.11 No studies have been con-
ducted to assess the safety and efficacy of
guarana alone or without the aid of other
substances. In a double-blind RCT, the ef-
fects of a guarana and yerba mat´
e contain-
ing supplement on weight loss and gastric
emptying were found to cause delayed gas-
tric emptying and contributed to more short-
term weight loss over 45 days in 44 healthy
overweight subjects than in controls.16 How-
ever, no significant effect was found after 1
year of treatment.16 Adverse events reported
with guarana include heart palpitations, irri-
tability, anxiety, and other CNS symptoms.12
The combination of guarana and ephedra
can cause serious adverse events, with in-
creased heart rate, increased blood pressure,
and impairment of potassium and glucose
homeostasis.17 Guarana, when taken in high
doses, can cause insomnia, anxiety, nausea,
vomiting, tremors, tachycardia, and arrhyth-
mia. Guarana, because of its high caffeine con-
tent, may interact with medications used in
the treatment of diabetes, anticoagulants, an-
tipsychotics, and other medications.11
Yerba mat´
e is prepared from the plant
Ilex paraguariensis, which is an evergreen
shrub native to South America. Only 1 study
was performed on yerba mat´
e and guarana
(mentioned earlier), with no adverse events
reported.12 More study is needed on these
Bitter orange
Citrus aurantium or bitter orange is a
small citrus tree (also known as Seville
Dietary and Herbal Supplements for Weight Loss 139
orange or sour orange). The active ingredients
in bitter orange are synephrine (oxydrine) and
octopamine, which are structurally similar to
epinephrine and norepinephrine and are also
closely related to ephedrine.18 Synephrine
is a sympathomimetic amine that stimulates
the CNS.7Dietary supplements containing
synephrine have been marketed as a safe alter-
native to ephedra,18 and many supplements
labeled “ephedra free” contain synephrine.19
There is little evidence to date that bitter or-
ange supplements are effective in weight loss,
and no clinical trials have been conducted
with bitter orange alone.19 Additional studies
are needed to assess the safety and efficacy of
bitter orange.7Because of the stimulant effect
of synephrine, bitter orange has the potential
to cause adverse effects such as high blood
pressure and other cardiovascular effects.10
Adverse reactions (tachycardia, dysrhyth-
mia, cardiac arrest, and ischemic stroke)
have been reported with combination
supplements containing bitter orange and
caffeine.10,13 Bitter orange also contains the
flavonoids, furocoumarin and bergapten,
which can inhibit CYP3A4, may affect the
metabolism of some drugs, and could po-
tentially increase the serum levels of these
drugs (such as warfarin).18 Additional safety
testing and assessments of drug interactions
are needed.7
Guar gum, glucomannan, and psyllium
Guar gum, glucomannan, and psyllium are
soluble fibers that are claimed to help in
weight loss through their ability to absorb
water in the intestine, resulting in increased
satiety.8Guar gum is a dietary fiber de-
rived from the Indian cluster bean Cyamop-
sis tetragonolobus. A meta-analysis of 20
double-blind, placebo-controlled trials con-
cluded that guar gum was not effective in re-
ducing body weight. In most of these trials,
subjects were instructed not to change their
eating habits.1,8,20 Adverse effects reported
were nausea, diarrhea, and flatulence.1,12 In
3% of subjects, the GI complaints were severe
enough to cause subjects to withdraw from
the trials.12
Glucomannan is prepared from the konjac
root Amorphophallus konjac, and it is struc-
turally very similar to galactomannan present
in guar gum.20 It is a highly viscous fiber21
and is reported to be the most water-soluble
fiber, expanding up to 200 times its original
volume when used with water. In animal stud-
ies, glucomannan has been shown to form a
gel around food particles and cause slower
absorption of carbohydrates and fat.22 Three
RCTs reported that, at a dosage of 2 to 4 g/d,
glucomannan results in modest but significant
weight loss. However, these trials were small
and had methodological limitations.8No ad-
verse events were reported.8,20 Glucomannan
improves glucose and lipid contents.21 Addi-
tional well-designed RCTs are needed to deter-
mine the efficacy and safety of glucomannan
on weight loss.
Psyllium fiber is derived from the plant
Plantago psyllium. Studies on psyllium fiber
did not show any effect on weight loss; how-
ever, its use resulted in the improvement in
lipid contents and glycemic control in 125
overweight subjects with type 2 diabetes.8
Adverse effects were reported with psyllium
fiber, which included flatulence, bloating, in-
digestion, and nausea.12
Hydroxycitric Acid
Hydroxycitric acid is extracted from the
Malabar tamarind tropical fruit Garcinia cam-
bogia, which is native to India.8It has been
shown to inhibit de novo fatty acid synthesis
by inhibiting the enzyme citrate lyase, which
catalyses the first step in fatty acid synthesis.3
Hydroxycitric acid has also been suggested
that it inhibits food intake by suppressing
appetite and decreases weight gain.20 The
evidence from several RCTs regarding the
efficacy of HCA is contradictory.8Some stud-
ies reported improvements in body compo-
sitions; however, these studies had limita-
tions and poor designs or had used HCA in
combination with other herbs.11 Hydroxyc-
itric acid is also sold as supplement with cal-
cium salts3and calcium and potassium salts.23
HCA-SX is a calcium-potassium salt of HCA
with high bioavailability, which induces a
concentration-dependent release of serotonin
in rats and causes appetite suppression.23 In
a study of HCA-SX use, 60 human subjects
took 4666.7 mg of HCA-SX with 2000 kcal
of diet per day and participated in a 30-
minute walking exercise session 5 d/wk for 8
weeks. These authors found that the use of
HCA-SX resulted in decreases in body weight,
body mass index, food intake, serum choles-
terol, low-density lipoprotein cholesterol, and
triglycerides, and increases in high-density
lipoprotein (HDL) and serotonin levels.23 Ad-
ditional well-designed RCTs are needed to as-
sess the efficacy and long-term safety of HCA.
Adverse events observed with HCA in
some studies include stomach pain, GI symp-
toms, headache, and upper respiratory tract
symptoms.12,20 No drug-supplement interac-
tions has been reported.11
Green tea extracts
Green tea is derived from the leaves of
Camellia sinensis.3It contains the polyphe-
nols epigallocatechin gallate (EGCG), epicate-
chin (EC), and epicatechin gallate (ECG). Of
these, EGCG is the most abundant and most
biologically active ingredient.11
Green tea is believed to help weight loss by
promoting thermogenesis and fat oxidation.8
In vitro, GTEs containing catechins and caf-
feine are more potent in stimulating brown
adipose tissue thermogenesis than by caf-
feine alone.3It has also been shown in hu-
man studies that green tea and caffeine mix-
ture can stimulate thermogenesis and fat
oxidation in the short term.24 In few stud-
ies on rats and humans, green tea supple-
ments showed positive effect on reducing
body fat.5A recent double-blind RCT of 78
obese women found that the group receiv-
ing 400 mg of GTEs, 3 times per day for 12
weeks had a slight (0.3%) reduction in body
weight. However, they also had a significant
reduction in low-density lipoprotein choles-
terol and triglycerides and marked increases
in HDL-cholesterol, adiponectin, and ghrelin
compared with the control group.25 Green
tea has also been suggested to limit weight
regain after weight loss and to offset the re-
duction in energy expenditure resulting from
weight loss.26 A randomized, double-blind,
placebo-controlled trial assessed weight loss
and weight maintenance with green tea sup-
plementation and habitual caffeine intake on
76 overweight/obese subjects, who adopted a
very low-calorie diet for 4 weeks, followed by
3 months of weight maintenance. During the
maintenance period, the study group received
green tea-caffeine mixture (270 mg of EGCG
and 150 mg of caffeine), and habitual caffeine
intake was also assessed. The results found
that those with low caffeine intake (<300
mg/d), taking the green tea-caffeine supple-
ments, still reduced body weight and body
fat during the maintenance period with an
increase in resting energy expenditure com-
pared with controls, whereas those with high
caffeine intake (>300 mg/d), no effect of the
supplement was observed. The authors con-
cluded that GTE-caffeine mixture could im-
prove weight maintenance in persons with
low habitual caffeine intake.26 A recent meta-
analysis that included 11 studies on the effect
of green tea on weight loss and weight main-
tenance found that catechins and EGCG sig-
nificantly decreased body weight and signif-
icantly maintained body weight after weight
loss.27 Interestingly, the effect was smaller
in whites than in Asians. It was also sug-
gested that habitual caffeine intake and eth-
nicity might be moderators that may influ-
ence the effect of green tea.27 Safety concerns
about GTEs were raised after reported hepa-
totoxicity from the supplements in Europe.28
Recently, regulatory agencies in France and
Spain suspended market authorization of
weight loss products containing GTEs be-
cause of hepatotoxicity. As a response, the
US Pharmacopeia Dietary Supplement Infor-
mation Expert Committee systematically re-
viewed the safety information of GTEs. A total
of 216 case reports on GTEs were analyzed,
of which 34 reports documented liver dam-
age. The implicated products that contained
GTE in these cases were Exolise, Tealine, Hy-
droxycut, TRA Complex, Camiline Arkocaps
Dietary and Herbal Supplements for Weight Loss 141
tea leaf powder, and GreenLite Polyphenon.29
Clinical and toxicological data indicated that
concentrated extracts of green tea when con-
sumed on an empty stomach, are more likely
to lead to adverse effects than when con-
sumed in the fed state.29 Therefore, it was rec-
ommended that GTE products carry the label-
ing statement: “Take with food. Discontinue
use and consult a healthcare practitioner if
you have a liver disorder or develop symp-
toms of liver trouble such as abdominal pain,
dark urine, or jaundice.”
29(p482) No safety con-
cerns are associated with the consumption of
green tea as a beverage. There is also some
speculation that GTEs may interfere with iron
Conjugated linoleic acid
Conjugated linoleic acid is an isomer of
linoleic acid (cis-9,trans-11) that is found nat-
urally in the rumen of cattle.3It can be found
in the human diet primarily in meat and dairy
and meat products. An average diet supplies
15 to 174 mg of CLA per day.10 In supple-
ments, it is found in a mix of 2 isomers (cis-
9,trans-11 and cis-12,trans 10).30 Conjugated
linoleic acid reduces fat mass and fat depo-
sition in obese mice, probably by increasing
lipolysis and decreasing triglycerides uptake
in the adipose tissue.8Most studies on the ef-
fects of CLA on body composition were per-
formed on animals. Mice were found to be
more responsive, with 60% less total body fat
in treated animals.30 There is little evidence
on the efficacy of CLA in reducing body fat
or body weight in humans.7A recent meta-
analysis on the efficacy of CLA in reducing fat
mass, which included 18 randomized, double-
blind, placebo-controlled studies found that
at a dose of 3.2 g/d, CLA resulted in modest
losses in body fat (0.5 kg/wk) in humans up
to 6 months as compared with those with a
Safety concerns about CLA are related to
several risk factors for chronic disease.30
There has been an increase in insulin resis-
tance in animals treated with CLA,3as well
as in humans with abdominal obesity and
diabetes taking the cis-12,trans-10 isomer.11
It has also shown to cause modest increase
in some inflammatory markers including C-
reactive protein, white blood cell counts, and
blood and urinary isoprostane. Although CLA
increases these inflammatory biomarkers, it
decreases inflammatory disease in several an-
imal studies.30 The effects of CLA on inflam-
matory markers and insulin resistance need to
be studied further.30 Other adverse effects in-
clude mild to moderate GI symptoms in hu-
mans taking CLA.8
Capsaicin is a substance found in the Cap-
sicum species of chili pepper and red pepper.
It is suggested that it stimulates fat oxidation
and thermogenesis3and decreases appetite.31
There are reports of modest weight loss in
individuals who consume chili peppers
regularly.3No studies were performed
on the use of capsaicin alone for weight
loss.5One double-blind, placebo-controlled
study assessed the effects of a combina-
tion of supplements that included tyrosine,
capsaicin, catechins, caffeine, and calcium
on body fat loss and thermogenesis on 80
overweight/obese subjects for 8 weeks. In
the first 4 weeks, the subjects followed a
hypocaloric diet and in the next 4 weeks they
were given the bioactive supplement. In this
study, the supplement combination was sug-
gested to work in a synergistic fashion. The
results demonstrated that the supplement
increased thermogenesis and caused a slight
reduction in fat mass (0.9 kg) compared with
a placebo.31 Additional studies are needed on
capsaicin alone to assess its efficacy.
Some adverse effects such as diarrhea have
been reported.5Capsaicin may reduce the
bioavailability of aspirin.5
Also known as l-carnitine, it is synthesized
in the body from the amino acids lysine and
methionine. Carnitine plays a central role in
fat metabolism by transferring long-chain fatty
acids to the mitochondria for β-oxidation.11 It
is also found in food, primarily in red meat,
with the average nonvegetarian diet provid-
ing 100 to 300 mg of carnitine per day. Car-
nitine deficiency is associated with muscle
weakness and fatty acid accumulation.11 Car-
nitine supplements have been used for sev-
eral medical conditions and for the enhance-
ment of athletic performance.10 The use of
carnitine for weight loss has not been ade-
quately studied to evaluate for its efficacy.
One double-blind, placebo-controlled study
was conducted on 36 overweight subjects re-
ceiving 4 g of l-carnitine per day, or a placebo
for 8 weeks. The group of subjects receiving
carnitine did not have significant changes of
body weight or fat mass.11 More research is
needed to assess the effectiveness of carni-
tine on weight loss. Five of the subjects in
this study experienced nausea and diarrhea.11
l-Carnitine may inhibit thyroid hormone ac-
tivity; therefore, the supplement should be
avoided in hypothyroidism.10,11
Pyruvate is produced in the body from
the end stage of glycolysis.11 Pyruvate sup-
plements are used for athletic performance
and weight loss and are sold in the form of
sodium or calcium pyruvate.10,11 Preliminary
research suggest that pyruvate may increase
fat oxidation.10 A systematic review included
2 double-blind, controlled trials on obese sub-
jects (n=52 and n=104) with a dose of 6 g
of pyruvate per day for 6 weeks, with subjects
consuming a 2000-kcal diet and participating
in exercise program 3 d/wk. It was found that
pyruvate did not cause greater weight loss
than with the placebo.20 There is preliminary
evidence that pyruvate combined with a low-
calorie diet, or taken in place of a portion
of dietary carbohydrate, seems to increase
weight loss and decrease body fat.10 More re-
search is needed to assess the efficacy of pyru-
vate on weight loss. Adverse effects reported
with high doses of pyruvate included gastric
Chitosan is an amino polysaccharide that is
structurally similar to the dietary fiber cellu-
lose. It is derived from chitin, which is found
in the exoskeleton of insects and crustaceans
such as shrimp.11 It is a positively charged
polymer that is suggested to bind to the neg-
atively charged fat molecules in the intestinal
lumen.8In in vitro demonstrations, chitosan is
mixed with corn oil in a glass, which results in
the precipitation of the oil and clearing up of
the solution. It is suggested that it works as a
“fat blocker,” helping weight loss.3Evidence
regarding the efficacy of chitosan in reduc-
ing body weight is not compelling.7A recent
systematic review on the effectiveness of chi-
tosan supplements for the treatment of over-
weight found that there is some evidence that
chitosan is more effective than a placebo in
short-term treatment of overweight and obe-
sity; however, many of these studies had lim-
itations and poor design.32 Results from well-
designed trials indicate that the effect of chi-
tosan on body weight is minimal and of lit-
tle clinical significance.32 Therefore, it seems
that the ability of chitosan to bind fat in vitro
cannot translate to significant fat-binding ef-
fects in the human body.3
Adverse effects of chitosan include
GI symptoms such as constipation and
flatulence.12 Chitosan may interfere with
the absorption of fat-soluble vitamins and
some minerals. The long-term effect on bone
health, nutrient deficiencies, and malabsorp-
tion syndromes need to be determined.11
Chromium is an essential trace mineral
that acts as a cofactor of insulin and en-
hances the action of this hormone by possi-
bly increasing affinity to receptors and insulin
binding to cells.10 Therefore, chromium plays
an important role in carbohydrate and lipid
metabolism.21 Chromium deficiency is asso-
ciated with hyperglycemia, hyperinsulinemia,
high triglycerides, and low HDL cholesterol.8
Chromium, as a supplement, is available as
Dietary and Herbal Supplements for Weight Loss 143
a complex of trivalent chromium and pi-
colinic acid (a derivative of tryptophan).7
Other forms of chromium are available as
supplements; however, chromium picolinate
has the highest bioavailability and lowest
toxicity.33 Chromium supplements have been
promoted to aid in weight loss, for muscle
building, and to lower glucose in persons
with diabetes.11 For weight loss, the dosage
used is 200 to 400 μg.8However, there is lit-
tle evidence on its efficacy on body weight.
A meta-analysis of 10 RCTs on the effect of
chromium supplementation on body weight
found a small reduction in weight (0.08–
0.2 kg/wk) in the chromium-receiving group
compared with controls, which was not clin-
ically significant.11,18 A double-blind RCT that
tested the effects of 200 μg of supplementa-
tion of chromium picolinate on 83 women,
who took controlled energy intake for 12
weeks, did not result in a reduction in body
weight or change in body composition.33 An-
other recent study on 35 overweight pre-
menopausal women assessed the effect of
the combination of chromium and CLA on
body weight and body composition, with con-
sumption of hypocaloric diets for 12 weeks.
The study found that both supplements
did not enhance diet or impact exercise-
induced changes in weight, body composi-
tion, and lipid parameters compared with a
No adverse events were reported with
chromium picolinate use in short-term
trials.20 However, there is concern that this
form of chromium can lead to free radical
damage on the long term. Some preliminary
analysis suggests that chromium might act
as prooxidant in euglycemic patients. Other
research suggests that chromium can be ox-
idized to hexavalent chromium. The clinical
significance of these findings is unknown.10
In high doses (¿1000 μg/d), renal failure
and rhabdomyolysis have been reported.8
Examining drug-supplement interactions,
some medications such as nonsteroidal anti-
inflammatory drugs and vitamin C have been
found to increase chromium absorption,
whereas antacids, H2blockers, and proton
pump inhibitors can decrease chromium
Calcium and vitamin D
Calcium is an important mineral that has
been claimed to help with weight loss in addi-
tion to many other functions. One of the pro-
posed weight loss mechanisms is that calcium
can increase fecal fat excretion.35 Evidence
on calcium supplement effects on weight loss
in human studies is inconsistent and the ef-
ficacy is limited to small trials.7Calcium con-
sumption from dairy foods has been shown to
be more effective in weight loss than calcium
from supplements.35 A systematic review
by Trowman et al,36 who performed meta-
analysis on 13 RCTs, on the effects of calcium
supplementation on body weight concluded
that calcium, from either dairy or supple-
ments, did not result in statistically signifi-
cant reduction in body weight.36 A larger,
more recent systematic review by Lanou et
al,37 which included 19 trials and separated
isocaloric from energy restricted trials, found
that 16 of the trials (8 on calcium supplements
and 8 on dairy products) reported no signifi-
cant effect of calcium on body weight. Of the
3 remaining trials, 1 supplement trial found
significant weight loss and 2 dairy trials found
significantly greater weight gain. The weight
gain is caused by increased energy intake from
the dairy.38 The majority of the calcium stud-
ies were done on postmenopausal women,
and few trials included men.38 One large ran-
domized, double-blinded, placebo-controlled
trial investigated the role of calcium plus vita-
min D supplementation in the prevention of
weight gain in postmenopausal women. The
study included 36 282 women, aged 50 to
79 years, who were randomized to 1000 mg
of calcium and 400 IU of vitamin D intakes
daily or a placebo. Changes in body weight
were monitored for 7 years. It revealed that
women who received calcium and vitamin
D had smaller favorable changes in weight
(0.13 kg) and were 11% less likely to gain
weight (1–3 kg). It was concluded that cal-
cium and vitamin D had a small effect on pre-
vention of weight gain in this population.39
Vitamin D is essential for maintaining cal-
cium homeostasis in the body.11 The effect of
vitamin D alone on weight has not been ad-
equately studied.38 Some population studies
have shown that people with low vitamin D
level are significantly more likely to be obese
that those with high vitamin D levels.10 One
systematic review on the effect of vitamin D
and weight loss identified 3 RCTs that were
published in 1997, 2008, and 2009, respec-
tively. The studies were on postmenopausal
women, obese men and women, and on obese
men, respectively, and compared different
dosages of vitamin D to a placebo (300 IU/d,
20 000–40 000 IU/wk, or 120 000 IU every 2
weeks, respectively). In all 3 studies, no differ-
ences in weight change with or without vita-
min D supplementation were observed.38
No safety concerns were identified with
calcium supplements.7Calcium supplementa-
tion is not recommended for individuals with
absorptive hypercalciuria, primary hyperthy-
roidism, renal insufficiency, or sarcoidosis.11
Vitamin D is toxic at doses above the tolera-
ble upper intake level of 2000 IU.11
Fish oil
Fish oil is a source of omega-3 fatty acids
eicosapentaenoic acid (EPA) and docosa-
hexaenoic acid (DHA).12 It has documented
effects on reducing serum triglycerides
levels and reducing the risk of develop-
ing cardiovascular disease and decreasing
inflammation.10,12 Some evidence indicates
that taking fish oil from dietary sources could
improve weight loss and decrease blood glu-
cose in overweight individuals.10 In animal
studies, EPA and DHA reduce weight and fat
deposition by inhibiting enzymes important
for lipid synthesis, but the effect is less clear
in human studies.40 In an RCT on 75 subjects
who were randomized to receive 6 g of fish
oil per day (providing 260 mg of DHA and 60
mg of EPA), fish oil and exercise, sunflower
oil (control), or sunflower oil and exercise
for 12 weeks, the findings have shown that
both fish oil and exercise independently
reduced body fat. Also, fish oil supplements
reduced plasma lipids and increased HDL
cholesterol.40 Additional studies are needed
to assess the efficacy of fish oil on weight
loss. Supplements of fish oils in high doses
(>3 g/d) may cause some adverse effects,
including inhibition of platelet aggregation,
increased risk of bleeding, and increased
risk for hemorrhagic stroke.10 There is also
concern that some fish oil preparation may be
contaminated with toxins such as mercury,
polychlorinated biphenyls, and dioxins.10
Bean pod (Phaseolus vulgaris)
Phaseolus vulgaris extracts are used for
hypercholesterolemia, weight loss, and other
conditions.10 Extracts of bean pods are re-
ferred as “starch blockers”and are claimed to
decrease carbohydrate digestion and absorp-
tion. Research on humans with specific bean
pod extracts (Phaseolamin) taken with meals
did not show that it inhibits starch breakdown
and absorption.10 In a double-blind RCT on
24 obese men, 3000 mg of bean pods per
day was given to the study group for 8 weeks
and found that the supplement resulted in
decreases in body weight with 129% differ-
ence and also a decrease in triglycerides levels
compared with a placebo.13 The current evi-
dence for the efficacy of bean pods on weight
loss is contradictory, and additional studies
are needed.10 Adverse reactions to bean pods
include nausea, vomiting, diarrhea, and stom-
ach pain.
Cissus quadrangularis
Cissus quadrangularis (CQ) is a succu-
lent vine found in Africa and Asia and has
medicinal use in some parts of Asia. The
supplement is used for weight loss, diabetes,
and hyperlipidemia.10 There is some pre-
liminary research to suggest that CQ may
help in weight loss. Two double-blind RCTs,
which were conducted on overweight/obese
subjects by Oben et al,41,42 were identified in
a recent systematic review. Participants were
given a dose of 300 mg of CQ per day and 300
mg of CQ +500 mg of Irvingia gabonensis
Dietary and Herbal Supplements for Weight Loss 145
(IG) per day, respectively. Both studies
showed significant decreases in body weight,
body fat, and waist size in the CQ group,
with larger reductions in the combination
group (CQ +IG). There was also a significant
decrease in serum cholesterol and glucose
levels in the supplement group.13 Additional
studies are needed to assess the efficacy of
CQ on weight loss. Some adverse effects have
been reported with specific CQ combination
product (Cylaris; Iovate Health Sciences
Research, Oakville, Canada), which include
headache, flatulence, dry mouth, diarrhea,
and insomnia.10
Caralluma or Caralluma fimbriate is an ed-
ible cactus found in India. Traditionally, it was
used by Indian tribes to suppress hunger dur-
ing prolonged hunts.10 Currently, there is in-
sufficient evidence to rate the efficacy of car-
alluma on weight loss.10 Only 1 RCT on the
supplement was identified in a recent system-
atic review, in which 50 overweight individu-
als were randomized to either weight loss pro-
gram plus 1 g of caralluma extract, or weight
loss program alone, for 60 days. The Caral-
luma species significantly decreases waist cir-
cumference and hunger, but no significant de-
creases in body weight, body mass index, and
hip circumference compared with controls.13
Some adverse effects were reported that in-
clude GI upset, flatulence, and constipation;
however, these effects appear to improve
within the first week of use.10
Hoodia gordonii is a succulent plant found
in Africa. It is marketed as a natural appetite
suppressant for weight loss.43 It is claimed
to be one of the glycosides that can act on
the CNS to control hunger; however, the ex-
act mechanism is not understood.10 There
are no published human studies on hoodia.
One animal study on rats showed that com-
pounds from Hoodia species, at all dosages
(6.25–50 mg/kg), resulted in decreases in
food consumption for a period of 8 days when
compared with controls.44 Human RCTs are
needed to determine the efficacy and safety of
hoodia supplements. No adverse effects have
been reported. New reports show that certain
hoodia products sold on the Internet do not
contain the active compounds.10
Dehydroepiandrosterone (DHEA) is the
most abundant hormone secreted by the
adrenal glands and can be converted to andro-
gens or estrogens.11 Its supplements are com-
monly used for slowing aging, weight loss,
metabolic syndrome, and increasing immune
and cognitive functions. Currently, there is in-
sufficient evidence on the efficacy of DHEA
on weight loss. Some preliminary evidence
suggests that taking 50 mg of DHEA per
day may reduce risk factors for metabolic
syndrome in overweight elderly patients. No
studies were performed on younger popula-
tion; therefore, more research is needed.10
The safety of long-term DHEA use is un-
known. High doses of 200 mg of DHEA per
day may cause masculinization in women
(deepening of voice, facial hair, acne, hair
loss, and menstrual irregularities) because of
the rise in testosterone levels.10,11
Hydroxymethyl butyrate (HMB)
Hydroxymethyl butyrate is a metabolite of
the amino acid leucine, a precursor of choles-
terol, and is produced mainly in muscles and
liver.10,11 Its supplements are used for weight
training to both increase muscle strength and
lean mass. There are no studies regarding
its use for weight loss.11 Hydroxymethyl bu-
tyrate supplements are possibly safe when
used for short term, and no adverse effects are
reported.10 More research on hydroxymethyl
butyrate is needed.
Dandelion and cascara
Dandelion (Taraxacum officinale) is a di-
uretic and cascara (Rhamnus purshiana)
is a laxative, and both can increase water
elimination.8There are no studies on either of
the supplements on their use for weight loss.
Adverse effects from their use include dehy-
dration and electrolyte imbalance.8,10
Table 1. Summary of the commonly used dietary supplements for weight loss and evidence for
their efficacy and safety
Proposed mechanism Evidence of
Supplement of action efficacy Evidence of safety
Ephedra Increase energy
There is evidence of
short-term efficacy
(<6 mo)
GI, autonomic, and
symptoms, heart
palpitations, possible
seizure, stroke, death
Sales were prohibited in
guarana, and
yerba mat´
Increase energy
Some evidence on the
efficacy of caffeine
and ephedrine
Insufficient evidence for
guarana and yerba
Heart palpitation,
irritability, anxiety, dry
mouth, headache, and
Some caffeine-based,
ephedra-free products
were associated with
liver damage,
hypertension, stroke,
and retinopathy
No adverse effects with
yerba mat´
Bitter orange Increase energy
Insufficient evidence May cause hypertension.
Some reported
cardiovascular effects.
May increase toxicity
of warfarin
Glucomannan Increase satiety Insufficient evidence No adverse effects
Psyllium Increase satiety No evidence Flatulence, bloating,
Guar gum Increase satiety No evidence Nausea, diarrhea,
Increase fat oxidation No clear evidence GI symptoms, headache
Green tea
Increase fat oxidation Some evidence from
human studies on
reducing body weight
and body fat and
improving weight
Reported liver toxicity
May interfere with iron
linoleic acid
Increase fat oxidation Some evidence GI symptoms
May cause insulin
Capsaicin Increase fat oxidation
Decrease appetite
Insufficient evidence Diarrhea
May reduce the
bioavailability of
Carnitine Increase fat oxidation Insufficient evidence Nausea, diarrhea
May inhibit thyroid
Pyruvate Increase fat oxidation Insufficient evidence
May be effective with a
low-calorie diet
Gastric distress with
high doses
Dietary and Herbal Supplements for Weight Loss 147
Table 1. Summary of the commonly used dietary supplements for weight loss and evidence for
their efficacy and safety (Continued)
Proposed mechanism Evidence of
Supplement of action efficacy Evidence of safety
Chitosan Block dietary fat
Some evidence of small
effect on weight loss,
but not clinically
Constipation, flatulence
May interfere with
absorption of
fat-soluble vitamins
and some minerals
Chromium Modulate carbohydrate
Little evidence, not
clinically significant
No short-term adverse
May lead to free radical
damage on the
long-term use
Reported renal failure
and rhabdomyolysis
with high doses
Calcium Increase fat excretion No clear evidence No adverse effects
Vitamin D Maintain calcium
Insufficient evidence Toxic above upper
intake level of 2000 IU
Fish oil Decrease fat deposition Evidence on decreasing
body fat in animal
studies; less clear
evidence in humans
In high doses (>3 g/d)
may increase risk of
bleeding and
hemorrhagic stroke;
supplements may
contain contaminants
and toxins
Bean pod Decrease carbohydrate
digestion and
Insufficient evidence Nausea, vomiting,
diarrhea, and stomach
Cissus quad-
Unspecified Insufficient evidence Headache, flatulence,
dry mouth, diarrhea,
and insomnia
Caralluma Suppress appetite Insufficient evidence GI upset, flatulence, and
Hoodia Suppress appetite Insufficient evidence
No human studies
No adverse reactions
Unspecified Insufficient evidence Masculinization in
women at high doses
(200 mg/d)
May increase lean mass Insufficient evidence No adverse effects
Dandelion and
Increase water
No studies on weight
Dehydration and
electrolyte imbalance
St. John’s wort Enhance mood No studies on weight
Insomnia, vivid dreams,
restlessness, anxiety,
agitation, irritability,
GI discomfort,
diarrhea, fatigue, dry
mouth, dizziness, and
photosensitivity in
high doses
Interact with many
prescription drugs
Abbreviation: GI, gastrointestinal.
St. John’s wort
St. John’s wort (Hypericum perforatum)is
often used in mild depression and is some-
times added to weight loss products to en-
hance mood; however, there are no data
available on its effect on weight loss.8Some
adverse effects reported include insomnia,
vivid dreams, restlessness, anxiety, agitation,
irritability, GI discomfort, diarrhea, fatigue,
dry mouth, and dizziness, as well as photosen-
sitivity in high doses. St. John’s wort is known
to interact with many prescription drugs and
reduce their levels of activity.10,11 The interac-
tion with some medications may lead to seri-
ous effects, such as cerebral vasoconstriction
disorders with antidepressants, hypertension,
hyperthermia, and coma with monoamine ox-
idase inhibitors, or severe swelling of face
with aminolevulinic acid.10
There are other supplements marketed
for weight loss, such as ginger roots, white
willow,5Laminaria,Spirulina,Guggul, and
apple cider vinegar,8but their safety and effi-
cacy have not been assessed in RCTs.
There are many dietary and herbal sup-
plements and about 125 combination supple-
ments that have been promoted for weight
loss. Some, such as ephedra, were exten-
sively studied; however, for many others, their
efficacy and safety were never determined
by well-designed, randomized, controlled tri-
als. The supplements discussed, with evi-
dence on their efficacy and safety, are sum-
marized in Table 1. Supplements are com-
monly used by Americans for weight loss, es-
pecially women.6Their use is also common
among adolescents.45 People often perceive
that these supplements are “natural”; there-
fore, they should be safe. However, reports
about the adverse events associated with the
use of some supplements raise concern about
their safety. In addition, the potential interac-
tion of some of these supplements with other
herbs, as well as with prescribed or over-the
counter drugs, may lead to serious effects, es-
pecially in the stimulant supplements11,15 and
St. John’s wort.10
Physicians, nutritionists, and other health-
care professionals need to be educated about
the different substances used in supplements.
They need to encourage their patients to re-
port any use of dietary and herbal supple-
ments and to caution their patients against any
drug-supplement interactions. Any adverse re-
actions related to supplement use can be re-
ported to the FDA at
or 1800-FDA-1088.7Well-designed, random-
ized, double-blind, placebo-controlled studies
are needed on many dietary and herbal sup-
plements to assess their efficacy and safety.
More regulations from the FDA on produc-
tion, sales, and marketing of the dietary sup-
plements would also be beneficial to ensure
that the products actually contain the ingre-
dients listed on the labels and are free from
contaminants, as well as, most important, to
protect the public from some of the harm-
ful effects associated with some supplements
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ments among U.S. adolescents. J Adolesc Health.
... (35) O tipo de ensaios efectuados com extractos, merece também atenção, -Glucomanano (fibra solúvel) (56) Absorção de água e, consequentemente, formação de um gel (56,57) -Diminuição do apetite por aumento do volume no estômago (56,57) -Meteorismo. (54) Diminuição da absorção de fármacos administrados por via oral (10) Camellia sinensis (L.) O.Kuntze, Chá verde Folhas secas (58,59) não fermentadas ou não oxidadas. (59) Polifenóis (epicatequina, epicatequinagalato, epigalocatequina e epigalocatequinagalato) (54,60) (58,(61)(62)(63) -Termogénese (61,64) -Estimulação da oxidação lipídica (61,64) -Perda de peso -Nervosismo (10) -Ansiedade (10) -Taquicardia (10) -Capsicum spp, Chili e Pimenta vermelha Bagas Capsaícina (54) -Estimulação da oxidação lipídica (54) -Termogénese (54) -Modesta perda de peso em consumidores habituais (58) -Diminuição do apetite (54) -Caralluma fimbriata, Caralluma -Flavonóides (65) Polifenóis (65) Glicosídeos pregnanos (66) Glicosídeos megastigmanos (66) Terpenóides (65) Saponinas (65,66) Fitosteróis (65,66) Capacidade de amplificação do sinal da função sensorial no hipotálamo (67) -Supressão do apetite (glicosídeos pregnanos) (66) -Diminuição significativa do perímetro da cintura (66) -Perturbações gastrointestinais (54) -Flatulência (54) -Obstipação (54) - (68,69) Flavonóides (68,69) Ácido ascórbico (68,69) Carotenos (68,69) Triterpenóides tetraciclícos (quercitina) (68,69) Inibição da lípase e da amílase 82) -Promoção da perda de peso (69) -Diminuição do peso e da gordura corporal (54) -Cefaleias (54) -Flatulência (54) -Xerostomia (54) -Insónia (54) -Citrus aurantium, Laranjeira-amarga Folhas (70) Sinefrina ou oxidrina (71) Octopamina (71) Outros alcalóides (71) Flavonóides. ...
... (54) Diminuição da absorção de fármacos administrados por via oral (10) Camellia sinensis (L.) O.Kuntze, Chá verde Folhas secas (58,59) não fermentadas ou não oxidadas. (59) Polifenóis (epicatequina, epicatequinagalato, epigalocatequina e epigalocatequinagalato) (54,60) (58,(61)(62)(63) -Termogénese (61,64) -Estimulação da oxidação lipídica (61,64) -Perda de peso -Nervosismo (10) -Ansiedade (10) -Taquicardia (10) -Capsicum spp, Chili e Pimenta vermelha Bagas Capsaícina (54) -Estimulação da oxidação lipídica (54) -Termogénese (54) -Modesta perda de peso em consumidores habituais (58) -Diminuição do apetite (54) -Caralluma fimbriata, Caralluma -Flavonóides (65) Polifenóis (65) Glicosídeos pregnanos (66) Glicosídeos megastigmanos (66) Terpenóides (65) Saponinas (65,66) Fitosteróis (65,66) Capacidade de amplificação do sinal da função sensorial no hipotálamo (67) -Supressão do apetite (glicosídeos pregnanos) (66) -Diminuição significativa do perímetro da cintura (66) -Perturbações gastrointestinais (54) -Flatulência (54) -Obstipação (54) - (68,69) Flavonóides (68,69) Ácido ascórbico (68,69) Carotenos (68,69) Triterpenóides tetraciclícos (quercitina) (68,69) Inibição da lípase e da amílase 82) -Promoção da perda de peso (69) -Diminuição do peso e da gordura corporal (54) -Cefaleias (54) -Flatulência (54) -Xerostomia (54) -Insónia (54) -Citrus aurantium, Laranjeira-amarga Folhas (70) Sinefrina ou oxidrina (71) Octopamina (71) Outros alcalóides (71) Flavonóides. (71) Aumento da termogénese e aceleração do metabolismo basal, devido à sua acção simpatomimética (70) , estimulante do sistema nervoso central (SNC) (71) . ...
... (54) Diminuição da absorção de fármacos administrados por via oral (10) Camellia sinensis (L.) O.Kuntze, Chá verde Folhas secas (58,59) não fermentadas ou não oxidadas. (59) Polifenóis (epicatequina, epicatequinagalato, epigalocatequina e epigalocatequinagalato) (54,60) (58,(61)(62)(63) -Termogénese (61,64) -Estimulação da oxidação lipídica (61,64) -Perda de peso -Nervosismo (10) -Ansiedade (10) -Taquicardia (10) -Capsicum spp, Chili e Pimenta vermelha Bagas Capsaícina (54) -Estimulação da oxidação lipídica (54) -Termogénese (54) -Modesta perda de peso em consumidores habituais (58) -Diminuição do apetite (54) -Caralluma fimbriata, Caralluma -Flavonóides (65) Polifenóis (65) Glicosídeos pregnanos (66) Glicosídeos megastigmanos (66) Terpenóides (65) Saponinas (65,66) Fitosteróis (65,66) Capacidade de amplificação do sinal da função sensorial no hipotálamo (67) -Supressão do apetite (glicosídeos pregnanos) (66) -Diminuição significativa do perímetro da cintura (66) -Perturbações gastrointestinais (54) -Flatulência (54) -Obstipação (54) - (68,69) Flavonóides (68,69) Ácido ascórbico (68,69) Carotenos (68,69) Triterpenóides tetraciclícos (quercitina) (68,69) Inibição da lípase e da amílase 82) -Promoção da perda de peso (69) -Diminuição do peso e da gordura corporal (54) -Cefaleias (54) -Flatulência (54) -Xerostomia (54) -Insónia (54) -Citrus aurantium, Laranjeira-amarga Folhas (70) Sinefrina ou oxidrina (71) Octopamina (71) Outros alcalóides (71) Flavonóides. (71) Aumento da termogénese e aceleração do metabolismo basal, devido à sua acção simpatomimética (70) , estimulante do sistema nervoso central (SNC) (71) . ...
... Various natural remedies that may suppress the feeling of appetite have been studied. Herbal drugs (e.g., green tea or yerba mate) and their extracts, fractions, and even isolates (e.g., catechins) are claimed to be useful for weight loss [8,[26][27][28][29][30]. Safety and clinical efficacy of those supplements often remain unclear, since such studies in food are not required by market regulatory authorities as in the pharmaceutical sector. ...
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The prevalence of obesity is increasing worldwide. Bioactive phytochemicals in food supplements are a trending approach to facilitate dieting and to improve patients’ adherence to reducing food and caloric intake. The aim of this systematic review was to assess efficacy and safety of the most commonly used bioactive phytochemicals with appetite/hunger-suppressing and/or satiety/fullness-increasing properties. To be eligible, studies needed to have included at least 10 patients per group aged 18 years or older with no serious health problems except for overweight or obesity. Of those studies, 32 met the inclusion criteria, in which 27 different plants were tested alone or as a combination, regarding their efficacy in suppressing appetite/hunger and/or increasing satiety/fullness. The plant extracts most tested were derived from Camellia sinensis (green tea), Capsicum annuum, and Coffea species. None of the plant extracts tested in several trials showed a consistent positive treatment effect. Furthermore, only a few adverse events were reported, but none serious. The findings revealed mostly inconclusive evidence that the tested bioactive phytochemicals are effective in suppressing appetite/hunger and/or increasing satiety/fullness. More systematic and high quality clinical studies are necessary to determine the benefits and safety of phytochemical complementary remedies for dampening the feeling of hunger during dieting.
... Thus, the focus of anti-obesity treatment has shifted toward herbal drugs. However, there are few concerns about the safety and efficacy of even herbal supplements as well (Alraei, 2010). ...
Purpose To determine the effect of OBERAY capsules on serum lipid profiles, plasma adiponectin levels, body fat, skin fold thickness and an anthropometric measurements in overweight and obese individuals. Methods In this randomized, double-blind, placebo-controlled study, 72 overweight and obese participants were randomly assigned to receive either 1000 mg of OBERAY or a placebo, daily for 180 days. At baseline, after 90 days and 180 days of treatment, anthropometric parameters, total cholesterol, high density lipoprotein, low density lipoprotein, very low density lipoprotein, triglycerides, plasma adiponectin, body fat and skin fold variables were measured. Results 180 days of OBERAY treatment resulted in a significant increase in mean high density lipoprotein and decrease in other lipid profiles, plasma adiponectin, BMI, Waist Circumference, total body fat, skin fold parameters, subcutaneous and skeletal muscle fat. Conclusion Our findings suggests that, OBERAY is an effective treatment of weight control in overweight and obese Indian population.
... Adulteration with synthetic compounds in slimming preparations of herbal origin has become a major health problem, which led to argumentation against uncontrolled therapy with herbal preparations. In early 2000s, US citizens have paid approximately worth of $30 billion/year on weight loss products, as overweight and obesity are amongst the most common public health problems in the USA (Heber, 2003;Alraei, 2010). According to an early interesting survey study based on search using "diet", "food" and "nutrition" as keywords via 365 websites, 76 of them contained dietary recommendations which were not suitable to the Canadian dietary guidelines and also included recommending advertisements on supplements and herbal weight loss products (Davison and Guan, 1996). ...
... Kelp, its constituent fucoxanthin, and other seaweed products were the topic of reviews and clinical trials on fat burners and weight loss products. [97][98][99] Further human research on the anorectic properties and safety of seaweed or its extract alone for weight loss is required. Table)-Abidov et al. conducted a randomized, double-blinded placebo-controlled study to examine the effects of Xanthi-gen® on weight management in obese premenopausal women (N = 151). ...
... However, there are few concerns about the safety and efficacy of even herbal supplements as well. [16] Adverse events including hepatic injury, psychiatric, autonomic, gastrointestinal and palpitations have been reported with the use of some herbal supplements. [17] These reports contradict the myth regarding the safety of herbals and calls for detailed scientific evaluation of herbal supplements before they are recommended. ...
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The aim of the following study is to evaluate the efficacy and safety of Caralluma fimbriata extract (CFE) in overweight and obese individuals in a prospective, randomized, placebo controlled trial. Commercially available CFE was assessed in overweight and obese individuals. A total of 89 patients were randomized into a treatment group (n = 47) and placebo group (n = 42) to receive either CFE in the form capsules/oral 500 mg b.d. for 12 weeks or matching placebo in similar way. Patients were evaluated clinically and biochemically at 4, 8 and 12 weeks for anthropometric measurements, appetite, biochemical investigations and other safety parameters. At the end of study period both CFE and placebo for 12 weeks caused only numerical reduction in weight, body mass index, waist circumference, hip circumference and waist hip ratio in overweight and obese individuals. However, these parameters failed to attain significant statistical levels (P ≥ 0.05). CFE and placebo both failed to elucidate any modification of the appetite. There were no significant changes in the biochemical and clinical parameters in both the test and placebo group. However, CFE was well-tolerated and adverse events noted were mild and transient in nature. A commercially available extract of CFE in an oral dose of 1 g/day claimed to have anti-obesity effect failed to yield any positive results on anthropometry and appetite in overweight and obese individuals beyond placebo. There were also no significant differences in the clinical and biochemical parameters. However, CFE was well tolerated. Thereby, underscoring the need to carry more research before CFE is recommended as an anti-obesity drug.
Thai Traditional medicine was developed more than 700 years ago, dating back to Sukhothai (1238–1438 CE), an officially recognized healing system alongside conventional medicine in Thailand. Thai Traditional medicine is defined as “the medicinal procedures concerned with examination, diagnosis, therapy, treatment or prevention of, or promotion and rehabilitation of the health of humans or animals, obstetrics, traditional Thai massage, and also includes the production of traditional Thai drugs and the invention of medicinal devices, base on knowledge or text that has been passed on from generation to generation.” Thai Traditional medicine is diverse and intricate system of health and well-being. It bears a high resemblance in treatment philosophy and medicinal plants used in Ayurveda, the ancient science of life developed in India. Presently, there are around 17,001 practitioners in Thai Traditional medicine; 23,409 practitioners in Thai traditional pharmacy; 5735 practitioners in Thai traditional midwifery; 332 practitioners in Thai massage and 660 practitioners in Applied Thai traditional medicine. Moreover, 74 herbal remedies are implemented in the National List of Essential Medicines 2018 and divided into two categories: (1) Thai Traditional Remedy and (2) Herbal Product. Therefore, the development of medicinal plants for use in primary health care is needed to be concerned. In 2018, Thai Herbal Pharmacopoeia was established providing 80 monographs on herbal drugs and herbal drug preparations. Thai Traditional medicine is gaining popularity and has become a part of the National Health Development Plan. The Ministry of Public Health has taken important steps toward the development, promotion, and protection of traditional medicine in Thailand.
Obez ve fazla vücut ağırlığına sahip olma durumu, dünyada yaklaşık olarak her üç kişiden birinde var olan metabolik bozukluklardan biri haline gelmiştir. Obezite tedavisi için en etkili çözüm, dengeli bir beslenme planı ile birlikte yaşam tarzı değişikliğinin oluşturulmasıdır. Ancak uzun vadede sürdürülmesi gereken bu yaşam tarzı değişikliği, obez bireylerin çoğu için uyum zorluğu nedeniyle başarısız sonuçlanmaktadır. Ağırlık kaybını sağlamadaki zorluklar bu kişileri, popülerliği artan besin desteklerine yöneltmektedir. Birçok bitkiden elde edilen ürünler, dünya nüfusunun çoğunluğu tarafından sağlığın iyileştirilmesi ve geliştirilmesi için kullanılmaktadır. Buna paralel olarak, obez ve fazla vücut ağırlığına sahip kişiler tarafından ağırlık kaybını destekleyeceği düşünülerek, besin desteklerinin kullanımı artış göstermiştir. Tüketilen besin desteklerinin içeriğindeki biyoaktif bileşikler; sindirim sisteminde görev alan enzimleri inhibe etme, lipit metabolizmasını arttırma, iştahı baskılama gibi çeşitli metabolik yollarla ağırlık regülasyonuna etki edebildiği varsayılarak fazla vücut ağırlığına sahip bireyler tarafından kullanılmaktadır. Bazı besin bileşenlerinin farklı metabolik yolaklarla ağırlık kontrolünü sağladığı bildirilmekle beraber, bunun aksi yönde insan sağlığını tehdit eden yan etkilerinin de olabileceği unutulmamalıdır. Bu nedenle, mevcut bilimsel veriler ve güvenli kullanım tavsiyelerinin dikkatlice araştırılması önem arz etmektedir. Bu derlemede, bazı besin desteklerinin ve ilaçların obeziteyi önlemedeki etki mekanizması araştırılmış, obeziteyi önleme ve tedavi etme stratejilerine bakış açısı sunmak amaçlanmıştır.
Herbal products are being increasingly used all over the world for preventive and therapeutic purposes because of the belief of their safety. They have become an important part of health care system in many countries since they can easily be purchased in the health food stores or online. However, the lack of sufficient study on their efficacy and toxicity, inadequate controls of their availability, reduce their safety. Unlike conventional drugs, herbal products are not regulated for purity and potency. Herbal products contain substances which can induce or inhibit enzymes that take part in drug metabolism. Therefore the concurrent use of drugs with some medicinal plants can cause serious adverse effects and can also decrease the efficacy of the therapy. Particularly, drugs with narrow therapeutic index and plants which can affect drug metabolizing enzymes when used together, may lead to unpredictable adverse reactions. Impurities, contaminants and adulterants found in the herbal products, are the most common malpractises in herbal raw-material trade. In this review the unpredictable adverse effects of herbal products due to their possible interactions with drugs and also due to the adulteration and contamination with prohibited chemicals will be discussed in detail.
Conference Paper
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For spaceborne SAR (Synthetic Aperture Radar) systems, the dispersive effects of the ionosphere on the propagation of the SAR signal can be a significant source of phase error. While at X-band frequencies the effects are small, current and future P-, Land C-band systems would benefit from ionospheric compensation to avoid errors in topographic retrieval. In this paper the focus is on the effects of the ionosphere on repeat-pass SAR interferometry from Pthrough X-bands and methods for their estimation which are demonstrated on L-band ALOS-PALSAR acquisitions.
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Different outcomes of the effect of green tea on weight loss (WL) and weight maintenance (WM) have been reported in studies with subjects differing in ethnicity and habitual caffeine intake. To elucidate by meta-analysis whether green tea indeed has a function in body weight regulation. English-language studies about WL and WM after green tea supplementation were identified through PubMed and based on the references from retrieved articles. Out of the 49 studies initially identified, a total of 11 articles fitted the inclusion criteria and provided useful information for the meta-analysis. Effect sizes (mean weight change in treatment versus control group) were computed and aggregated based on a random-effects model. The influence of several moderators on the effect sizes was examined. Catechins significantly decreased body weight and significantly maintained body weight after a period of WL (microcirc=-1.31 kg; P<0.001). Inhibition of this effect by high habitual caffeine intake (>300 mg per day) failed to reach significance (microcirc=-0.27 kg for high and microcirc=-1.60 kg for low habitual caffeine intake; P=0.09). Also, the seemingly smaller effect of catechins in Caucasian (microcirc=-0.82 kg) subjects compared with Asians (microcirc=-1.51 kg; P=0.37) did not reach significance. Interaction of ethnicity and caffeine intake was a significant moderator (P=0.04). Catechins or an epigallocatechin gallate (EGCG)-caffeine mixture have a small positive effect on WL and WM. The results suggest that habitual caffeine intake and ethnicity may be moderators, as they may influence the effect of catechins.
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This review focuses on the efficacy and safety of effective herbal medicines in the management of obesity in humans and animals. PubMed, Scopus, Google Scholar, Web of Science, and IranMedex databases were searched up to December 30, 2008. The search terms were "obesity" and ("herbal medicine" or "plant", "plant medicinal" or "medicine traditional") without narrowing or limiting search elements. All of the human and animal studies on the effects of herbs with the key outcome of change in anthropometric measures such as body weight and waist-hip circumference, body fat, amount of food intake, and appetite were included. In vitro studies, reviews, and letters to editors were excluded. Of the publications identified in the initial database, 915 results were identified and reviewed, and a total of 77 studies were included (19 human and 58 animal studies). Studies with Cissus quadrangularis (CQ), Sambucus nigra, Asparagus officinalis, Garcinia atroviridis, ephedra and caffeine, Slimax (extract of several plants including Zingiber officinale and Bofutsushosan) showed a significant decrease in body weight. In 41 animal studies, significant weight loss or inhibition of weight gain was found. No significant adverse effects or mortality were observed except in studies with supplements containing ephedra, caffeine and Bofutsushosan. In conclusion, compounds containing ephedra, CQ, ginseng, bitter melon, and zingiber were found to be effective in the management of obesity. Attention to these natural compounds would open a new approach for novel therapeutic and more effective agents.
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Although there remains controversy regarding the role of macronutrient balance in the etiology of obesity, the consumption of high-fat diets appears to be strongly implicated in its development. Evidence that fat oxidation does not adjust rapidly to acute increases in dietary fat, as well as a decreased capacity to oxidize fat in the postprandial state in the obese, suggest that diets high in fat may lead to the accumulation of fat stores. Novel data is also presented suggesting that in rodents, high-fat diets may lead to the development of leptin resistance in skeletal muscle and subsequent accumulations of muscle triacylglycerol. Nevertheless, several current fad diets recommend drastically reduced carbohydrate intake, with a concurrent increase in fat content. Such recommendations are based on the underlying assumption that by reducing circulating insulin levels, lipolysis and lipid oxidation will be enhanced and fat storage reduced. Numerous supplements are purported to increase fat oxidation (carnitine, conjugated linoleic acid), increase metabolic rate (ephedrine, pyruvate), or inhibit hepatic lipogenesis (hydroxycitrate). All of these compounds are currently marketed in supplemental form to increase weight loss, but few have actually been shown to be effective in scientific studies. To date, there is little or no evidence supporting that carnitine or hydroxycitrate supplementation are of any value for weight loss in humans. Supplements such as pyruvate have been shown to be effective at high dosages, but there is little mechanistic information to explain its purported effect or data to indicate its effectiveness at lower dosages. Conjugated linoleic acid has been shown to stimulate fat utilization and decrease body fat content in mice but has not been tested in humans. The effects of ephedrine, in conjunction with methylxanthines and aspirin, in humans appears unequivocal but includes various cardiovascular side effects. None of these compounds have been tested for their effectiveness or safety over prolonged periods of time.
The Agency for Healthcare Research and Quality (AHRQ), through its Evidence-based Practice Centers (EPCs), sponsors the development of evidence reports and technology assessments to assist public-and private-sector organizations in their efforts to improve ...
Background: Regular exercise and consuming long-chain n-3 fatty acids (FAs) from fish or fish oil can independently improve cardiovascular and metabolic health, but combining these lifestyle modifications may be more effective than either treatment alone. Objective: We examined the individual and combined effects of n-3 FA supplements and regular exercise on body composition and cardiovascular health. Design: Overweight volunteers [body mass index (BMI; in kg/m2): >25] with high blood pressure, cholesterol, or triacylglycerols were randomly assigned to one of the following interventions: fish oil (FO), FO and exercise (FOX), sunflower oil (SO; control), or SO and exercise (SOX). Subjects consumed 6 g tuna FO/d (≈1.9 g n-3 FA) or 6 g SO/d. The exercise groups walked 3 d/wk for 45 min at 75% age-predicted maximal heart rate. Plasma lipids, blood pressure, and arterial function were assessed at 0, 6, and 12 wk. Body composition was assessed by dual-energy X-ray absorptiometry at 0 and 12 wk only. Results: FO supplementation lowered triacylglycerols, increased HDL cholesterol, and improved endothelium-dependent arterial vasodilation (P < 0.05). Exercise improved arterial compliance (P < 0.05). Both fish oil and exercise independently reduced body fat (P < 0.05). Conclusions: FO supplements and regular exercise both reduce body fat and improve cardiovascular and metabolic health. Increasing intake of n-3 FAs could be a useful adjunct to exercise programs aimed at improving body composition and decreasing cardiovascular disease risk.
Green tea [Camellia sinensis (L.) Kuntze] is the fourth most commonly used dietary supplement in the US. Recently, regulatory agencies in France and Spain suspended market authorization of a weight-loss product containing green tea extract because of hepatotoxicity concerns. This was followed by publication of adverse event case reports involving green tea products. In response, the US Pharmacopeia (USP) Dietary Supplement Information Expert Committee (DSI EC) systematically reviewed the safety information for green tea products in order to re-evaluate the current safety class to which these products are assigned. DSI EC searched PubMed (January 1966–June 2007) and EMBASE (January 1988–June 2007) for clinical case reports and animal pharmacological or toxicological information. Reports were also obtained from a diverse range of other sources, including published reviews, the US FDA MedWatch programme, USP’s MEDMARX® adverse event reporting system, the Australian Therapeutic Goods Administration, the UK Medicines and Healthcare products Regulatory Agency, and Health Canada’s Canadian Adverse Drug Reaction Monitoring Program. Case reports pertaining to liver damage were evaluated according to the Naranjo causality algorithm scale. In addition, the Committee analysed information concerning historical use, regulatory status, and current extent of use of green tea products. A total of 216 case reports on green tea products were analysed, including 34 reports concerning liver damage. Twenty-seven reports pertaining to liver damage were categorized as possible causality and seven as probable causality. Clinical pharmacokinetic and animal toxicological information indicated that consumption of green tea concentrated extracts on an empty stomach is more likely to lead to adverse effects than consumption in the fed state. Based on this safety review, the DSI EC determined that when dietary supplement products containing green tea extracts are used and formulated appropriately the Committee is unaware of significant safety issues that would prohibit monograph development, provided a caution statement is included in the labelling section. Following this decision, USP’s DSI ECs may develop monographs for green tea extracts, and USP may offer its verification programmes related to that dietary ingredient.
Background: Obesity is a well-established risk factor for cardiovascular disease, diabetes, hyperlipidemia, hypertension, osteoarthritis, and stroke. Stimulants, such as ephedrine and caffeine and their herbal counterparts, have proved effective in facilitating body weight loss, but their use is controversial due to their undesired effects. Other nutraceuticals have shown moderate success in reducing body weight, whereas several other compounds have demonstrated little or no effect. Therefore, a tolerable and effective nutraceutical that can increase energy expenditure and/or decrease caloric intake is desirable for body weight reduction.
Background: Chitosan, a deacetylated chitin, is a dietary supplement reported to decrease body weight. It is widely available over the counter worldwide and although evaluated in a number of trials its efficacy remains in dispute. Objectives: To assess the effects of chitosan as a treatment for overweight and obesity. Search strategy: We searched electronic databases (MEDLINE, EMBASE, BIOSIS, CINAHL, The Cochrane Library), specialised web sites (Controlled Trials, IBIDS, SIGLE, Reuter's Health Service, Natural Alternatives International, Pharmanutrients), bibliographies of relevant journal articles, and contacted relevant authors and manufacturers. Selection criteria: Trials were included in the review if they were randomised controlled trials of chitosan for a minimum of four weeks duration in adults who were overweight or obese. Authors of included studies were contacted for additional information where appropriate. Data collection and analysis: Details from eligible trials were extracted independently by two reviewers using a standardised data extraction form. Differences in data extraction were resolved by consensus. Continuous data were expressed as weighted mean differences and standard deviations. The pooled effect size was computed by using the inverse variance weighted method. Main results: Fifteen trials including a total of 1219 participants met the inclusion criteria. No trial to date has measured the effect of chitosan on mortality or morbidity. Analyses indicated that chitosan preparations result in a significantly greater weight loss (weighted mean difference -1.7 kg; 95% confidence interval (CI) -2.1 to -1.3 kg, P < 0.00001), decrease in total cholesterol (-0.2 mmol/L [95% CI -0.3 to -0.1], P < 0.00001), and a decrease in systolic and diastolic blood pressure compared with placebo. There were no clear differences between intervention and control groups in terms of frequency of adverse events or in faecal fat excretion. However, the quality of many studies was sub-optimal and analyses restricted to studies that met allocation concealment criteria, were larger, or of longer duration showed that such trials produced substantially smaller decreases in weight and total cholesterol. Authors' conclusions: There is some evidence that chitosan is more effective than placebo in the short-term treatment of overweight and obesity. However, many trials to date have been of poor quality and results have been variable. Results obtained from high quality trials indicate that the effect of chitosan on body weight is minimal and unlikely to be of clinical significance.
Several species of the stapeliads, a group of stem succulents belonging to the family Apocynaceae are reported on in the ethnopharmacology literature and many of the references relate to their use as food plants. The most important of these plants is Hoodia gordonii, which during the past decade has risen from an almost forgotten spiny, desert plant to an important commercial appetite-suppressant herbal. The aim of this review is to summarize the botany, ethnopharmacology and phytochemistry of Hoodia gordonii. Journal articles and books were used to collect information on Hoodia gordonii and related species. Many books and articles documented the use of stapeliad species as food plants and earlier references refer to the use Hoodia species as a thirst quencher. However, prior to the publication of the patent application, only a single reference referring to the use of Hoodia pilifera as appetite suppressant was found. The structures of several steroid glycosides isolated from Hoodia gordonii are summarized. Hoodia gordonii illustrates how a combination of ethnobotany and scientific research can lead to a commercial product which can greatly benefit the indigenous people.
Background: Obesity and overweight may soon affect more than half of the population in some regions of the world and are associated with diabetes, hypertension and other diseases that cause morbidity, mortality and high health-care expenditure. No one approach, whether dietetic management, medication, or commercial weight loss programme, can alone solve the problem--all potential treatments need to be investigated and exploited. Among the herbal preparations known to non-western cultures are materials which may have applications in modulating physiological processes which influence gut motility, food intake and energy balance. One such mixed herbal preparation is 'YGD' containing Yerbe Maté (leaves of Ilex paraguayenis), Guarana (seeds of Paullinia cupana) and Damiana (leaves of Turnera diffusa var. aphrodisiaca). Aims: This study had two distinct aims: to determine the effect of a herbal preparation 'YGD' containing Yerbe Maté, Guarana and Damiana on gastric emptying; to determine the effect of the same preparation on weight loss over 10 days and 45 days and weight maintenance over 12 months. Methods: Gastric emptying was observed using ultrasound scanning in seven healthy volunteers following YGD and placebo capsules taken with 420 mL apple juice. Body weight was observed before and after 10 days of treatment with three YGD capsules or three placebo capsules before each meal for 10 days in 44 healthy overweight patients attending a primary health care centre. Forty-seven healthy overweight patients entered a double-blind placebo-controlled parallel trial of three capsules of YGD capsules before each main meal for 45 days compared with three placebo capsules on body weight. Body weight was monitored in 22 patients who continued active (YGD capsules) treatment for 12 months. Results: The herb preparation YGD was followed by a prolonged gastric emptying time of 58 +/- 15 min compared to 38 +/- 7.6 min after placebo (P = 0.025). Body weight reductions were 0.8 +/- 0.05 kg after YGD capsules compared to 0.3 +/- 0.03 kg after placebo capsules over 10 days, and 5.1 +/- 0.5 kg after PGD capsules compared to 0.3 +/- 0.08 kg after placebo over 45 days. Active treatment with YGD capsules resulted in weight maintenance of the group (73 kg at the beginning and 72.5 kg at the end of 12 months). Conclusions: The herbal preparation, YGD capsules, significantly delayed gastric emptying, reduced the time to perceived gastric fullness and induced significant weight loss over 45 days in overweight patients treated in a primary health care context. Maintenance treatment given in an uncontrolled context resulted in no further weight loss, nor weight regain in the group as a whole. The herbal preparation is thus shown to be one that significantly modulates gastric emptying. Further clinical studies with dietetic monitoring of energy intake, dietary quality, satiety ratings, body weight and body composition are now indicated, and examination of the active principles contained in the three herbal components may prove rewarding.