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Herbal supplements, body fat, weight, mass; review of humans and animals

July 4, 2009

A systematic review of the efficacy and safety of herbal
medicines used in the treatment of obesity

Hasani-Ranjbar S, Nayebi N, Larijani B, Abdollahi M.
World J Gastroenterol. 2009 Jul 7;15(25):3073-3085. PMID: 19575486

http://www.wjgnet.com/1007-9327/15/3073.asp
http://www.wjgnet.com/1007-9327/15/3073.pdf

Change in human body weight
All studies showed loss of body weight except one[21]
which seemed to have problems with the study design,
and one other study[10] which showed a significant
decrease only in body fat. Studies with Cissus quadrangularis
(CQ)[26] or combined with Irvingia gabonensis (IG)[15], a
combination of Sambucus nigra and Asparagus officinalis[16],
calcium hydroxycitrate in Garcinia atroviridis[18], supplements
containing ephedra and caffeine[9,13,20], and Slimax as an
extract of several plants including Zingiber officinale[8] and
Bofutsushosan[14] showed significant decreases in body
weight.
Body fat
A significant decrease in body fat was shown with CQ[26],
supplements containing ephedra and caffeine[9,13], a natural
compound containing capsicum and some lipotropic
nutrients[10], Bofutsushosan[14], and calcium hydroxycitrate
in Garcinia atroviridis[18]. These phytopharmaceuticals
showed a significant decrease in triceps skin fold thickness
indicating significant loss of fat.
Waist and hip circumference
Efficient decreases in both waist and hip circumferences
in trials with a supplement containing ephedra and
caffeine[9] and Slimax (extract of several plants including
Zingiber officinale[8] were shown whereas Caralluma
fimbriata[19] and CQ with or without IG[15] significantly
decreased waist size.
Food intake
Decreases in appetite or amount of food or energy
intake with a supplement containing ephedra and
caffeine[20] and Caralluma fimbriata[19] were shown (not
significant) but hydroxycitric acid (HCA-SX) with or
without Gymnema sylvestre[23] decreased the amount of
food intake efficiently. A natural compound containing
capsicum and other lipotropic nutrients[10] did not
significantly change energy intake.

Published online: July 7, 2009

Abstract

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.

© 2009 The WJG Press and Baishideng. All rights reserved.

Key words: Animal; Herbal medicine; Human; Obesity

INTRODUCTION

The prevalence of obesity is increasing worldwide[1] resulting in an association with major health problems such as type 2 diabetes, ischemic heart disease, stroke, and cancer. It is necessary to treat obese individuals by both lifestyle interventions and/or pharmacological therapy. Pharmacologic treatment and surgical interventions used in some circumstances are not always appropriate[2]. Unfortunately, drug treatment of obesity despite short-term benefits, is often associated with rebound weight gain after the cessation of drug use, side effects from the medication, and the potential for drug abuse[3]. Pharmacologic options include sibutramine, orlistat, phentermine, diethylpropion, and fluoxetine or bupropion. Phentermine and diethylpropion have potential for abuse and are only approved for short-term use. Approved medications for long term use in the treatment of obesity are sibutramine and orlistat, however, these agents should be used with caution in patients with a history of cardiovascular disorders[4]. The general public uses many other methods for weight loss including herbs, vitamins, nutritional supplements, and meal replacement preparations. Rigorous scientific studies have not been carried out on these products, and in many cases safety and efficacy take a back seat to marketing.

Complementary and alternative therapies have long been used in the Eastern world but recently these therapies are being used increasingly worldwide[5]. When conventional medicine fails to treat chronic diseases and conditions such as obesity efficaciously and without adverse events, many people seek unconventional therapies including herbal medicine[6]. Although the number of randomized trials on complementary therapies has doubled every 5 years and the Cochrane library included 100 systematic reviews of unconventional interventions[7], none of these studies specifically mentioned herbal therapy in obesity.

This review aimed to evaluate the current science on the efficacy and safety of herbal medicines in the management of obesity.

DATA SOURCES AND STUDY SELECTIONS

PubMed, Scopus, Google Scholar, Web of Science, and IranMedex databases were searched up to December 30, 2008 for all human and animal studies investigating the effects (both harmful and beneficial) of treating obesity with herbal medicines. The search terms were “obesity” and (“herbal medicine” or “plant”, “plant medicinal” or “medicine traditional”) without narrowing or limiting search elements. Only publications with available abstracts were reviewed. The main outcome measures sought at the end of treatments as anti-obesity effects, were body weight, body fat including fat mass/fat weight or fat percentage/visceral adipose tissue weight, triceps skin fold thickness, waist or hip circumference, and appetite or amount of food intake.

Herbal medicines are defined in this review as raw or refined products derived from plants or parts of plants (e.g. leaves, stems, buds, flowers, roots, or tubers) used for the treatment of diseases. The synonyms of herbal medicines are herbal remedies, herbal medications, herbal products, herbal preparations, medicinal herbs, and phytopharmaceuticals, etc.

All of the abstracts from human and animal studies with the main outcome of change in anthropometric measures such as body weight and waist-hip circumference, body fat (weight or mass of visceral adipose tissue, fat mass or percent), amount of food intake, and appetite in participants were included. Even studies on other relevant diseases such as diabetes were also reviewed and included if the appropriate outcomes were shown. In vitro studies, review articles, and letters to the editor were excluded. Unpublished data such as theses were also excluded. Two reviewers independently examined the title, abstract and references of each article meeting the inclusion criteria and eliminated duplications and those showing exclusion criteria.

FINDINGS

Of the publications identified from the initial database search, 915 results were identified and reviewed for inclusion or exclusion. A total of 77 studies were included (19 human and 58 animal studies). Human studies included 17 randomized clinical trials (RCTs) and two before-after clinical trials[8-26]. RCTs reported random allocation of humans to herbal medicines vs (placebo/another plant/combination of plants) with or without specific dietary and exercise programs outlined in Tables 1 and 2 as weight loss programs. Human subjects were healthy overweight, obese or with impaired glucose tolerance test volunteers. Animal studies included healthy, genetically or experimentally obese or diabetic mice, rats and other rodents. The route of administration of herbs in almost all studies was oral intake with the exception of some animal studies as indicated in Table 2.

HUMAN STUDIES

Change in human body weight

All studies showed loss of body weight except one[21] which seemed to have problems with the study design, and one other study[10] which showed a significant decrease only in body fat. Studies with Cissus quadrangularis (CQ)[26] or combined with Irvingia gabonensis (IG)[15], a combination of Sambucus nigra and Asparagus officinalis[16], calcium hydroxycitrate in Garcinia atroviridis[18], supplements containing ephedra and caffeine[9,13,20], and Slimax as an extract of several plants including Zingiber officinale[8] and Bofutsushosan[14] showed significant decreases in body weight.

Body fat

A significant decrease in body fat was shown with CQ[26], supplements containing ephedra and caffeine[9,13], a natural compound containing capsicum and some lipotropic nutrients[10], Bofutsushosan[14], and calcium hydroxycitrate in Garcinia atroviridis[18]. These phytopharmaceuticals showed a significant decrease in triceps skin fold thickness indicating significant loss of fat.

Waist and hip circumference

Efficient decreases in both waist and hip circumferences in trials with a supplement containing ephedra and caffeine[9] and Slimax (extract of several plants including Zingiber officinale[8] were shown whereas Caralluma fimbriata[19] and CQ with or without IG[15] significantly decreased waist size.

Food intake

Decreases in appetite or amount of food or energy intake with a supplement containing ephedra and caffeine[20] and Caralluma fimbriata[19] were shown (not significant) but hydroxycitric acid (HCA-SX) with or without Gymnema sylvestre[23] decreased the amount of food intake efficiently. A natural compound containing capsicum and other lipotropic nutrients[10] did not significantly change energy intake.

Other effects

Anti-hyperlipidemic, antihyperglycemic, and other relevant anti-obesity effects of medicinal plants in human studies are summarized in Table 1.

Adverse effects

No significant adverse effects compared to controls were mentioned and no mortality was reported, except in studies with supplements containing ephedra and caffeine[9,20] which caused minor adverse effects such as dry mouth, insomnia, nervousness, palpitation and headache. Bofutsushosan[14] caused loose bowel movements.

ANIMAL STUDIES

Change in body weight and body fat

The majority of animal studies (41 out of 58) showed significant weight loss or inhibition of weight gain when supplemented with high fat diets containing extracts of plants, with or without an efficient decrease in fat mass[27-85] (Table 2).

Food intake

Clinical trials with Agave tequilana (TEQ) and Dasylirion spp (DAS)[30], Pomegranate leaf[43], Korean red ginseng[58], Tree peony[69], Gyeongshang angjeehwan containing a variety of plants including platycodongrandiflorum, Magnoliaceae and Ephedra[81], Parasitic loranthus[70], and Panax ginseng berry[85] showed significant reductions in food intake or appetite. In studies with Cucurbita moschata[40], Cyperus rotundus[42], Nomame Herba[66], Acanthopanax senticosus[57] PM-F2-OB (a traditional herbal medicine used for the treatment of obesity in Korea composed of Lycii Fructus), and several other plants[73], bofu-tsusho-san[79], Galega officinalis[77], and Oolong tea[67], no change in the amount of food intake or appetite was observed.

DISCUSSION

In many studies[8-10,12-16,20-23,27,39,73,74,79-81,83], a combination of plants or compounds containing minerals and or chemical extracts of plants were investigated and the scientific names are summarized in Tables 1 and 2. Most of these studies showed anti-obesity effects such as decreasing body weight in humans or body weight gain in animals with or without changes in body fat.

Currently available anti-obesity medications attack the body fat dilemma in three different ways. They can stimulate metabolism, suppress appetite, affect serotonin, or they can impede digestion of fat. In this review, we can categorize the target effects of herbal medicines in the same way.

Arachis hypogaea[50] decreased body weight gain, liver triglyceride content and liver size in association with increased fecal lipid excretion, suggesting an inhibitory mechanism on lipid absorption. Phillyrin[52], Allium victorialis[32], Pomegranate leaf[43], Kochia scoparia[46], Panax japonicus[55], Oolong tea[67], and Aesculus turbinata Blume[71] also had the same effect.

A decrease in food intake as a result of a decrease in appetite and an influence on hormonal status was observed with TEQ and DAS[30], Pomegranate leaf[43], Korean red ginseng[58], Tree peony[69], Gyeongshang angjeehwan containing a variety of plants including platycodon grandiflorum and Magnoliaceae and ephedra[81], and Parasitic loranthus[70], refined Rhubarb[34], Caralluma fimbriata[19] and Panax ginseng berry[85]. Possible stimulation of metabolism has been reported as a mechanism of action for compounds such as Slimax[8], supplements containing ephedra[9,13,14,20] and Terminalia arjuna Roxb[11] which showed modification of lipid metabolism and a reduction in serum lipid levels.

Ephedra known as Ma Huang is a well known natural product with amphetamine-like stimulation effects. Although it’s efficacy in weight loss need more investigations, its adverse effects are well established in the literature. In this review, nine studies investigated the effects of ephedra as one of the major components in the combinations with caffeine[9,13,22] or with several other plants[14,20,79,81,83] 5 of which were human studies[9,13,14,20,22].

In one study[13], efficient decreases in body weight and fat were observed with the administration of 210 mg caffeine and 72 mg ephedra per day for 12 wk with an improvement in lipid metabolism and blood pressure without serious adverse effects. In this study, the weight loss at 12-wk was -3.5 ± 0.6 kg with the test compound which was significantly (P < 0.02) higher than that of the placebo. The percentage fat loss shown by DXA was -7.9% ± 2.9% and -1.9% ± 1.1%, respectively (P < 0.05). In another study[20], ephedra at a dose of 40 mg/d and caffeine at a dose of 100 mg/d for a longer time (9 mo) was found to be more efficient than the previous study in lowering body fat and weight, improving lipid metabolism and blood pressure and had no serious adverse effects. The treatment group lost significantly more body weight (-7.18 kg) and body fat (-5.33 kg) than the control group (-2.25 and -0.99 kg, respectively). The difference in data from these two studies possibly resulted from the different dosages and duration of interventions.

In a human study[9], a significantly greater weight loss was observed (-4.0 ± 3.4 kg or 3.5% of baseline) in the test group vs (-0.8 ± 2.4 kg or 0.09% of baseline) in the placebo group. Changes were significantly greater for body fat and percentage of body fat in the active group (-3.5 ± 3.3 kg and -2.1% ± 3.0%) in comparison to the placebo group (-0.7 ± 2.9 kg and -0.2% ± 2.3%). The tested product also produced several untoward side effects, leading to some actively treated subjects withdrawing from the study. Additional long-term studies are needed to elucidate the effects of chronic treatment. Thus further examinations in healthy individuals using scientific combinations and dose/duration adjustments are required.

Four studies[58,59,65,76] investigated different doses and types of ginseng which is a very popular Chinese herbal medicine. Ginseng significantly decreased weight gain and efficiently improved glucose tolerance[59,76].

It has been reported[58] that hormonal influences can reduce food intake and decrease serum leptin and neuropeptide Y in the brain hypothalamus although not significantly. Thus the anti-obesity effect of this plant requires further investigation.

CQ, a succulent vine native to West Africa and Southeast Asia, has been used in traditional African and Ayurvedic medicine for more than a century. Although some studies have examined other uses for CQ, its role in fighting against obesity and for symptoms of metabolic syndrome has recently attracted interest in other parts of the world, because of its milder adverse effects comparing to ephedra. In this review, two studies focused on this herb[15,26]. CQ in combination with IG[15] induced marked reductions in body weight and fat. In addition, a reduction in waist size of 1.0 cm in the placebo group vs 21.9 cm in the CQ-IG group was observed.

As we focused on herbal medicines, all dietary interventions such as the consumption of fruits and vegetables, whole grains, different types of fibers, functional food components including omega three fatty acids or phytochemicals such as flavonoids were omitted. Lifestyle modification is still the safest and efficacious method of inducing a persistent weight loss. In this review, some of the studies were carried out on subjects who simultaneously received diet and exercise programs (mentioned as weight loss programs in Tables). These results demonstrated that specific phytochemical supplements increase the effectiveness of weight loss programs and additional significant anti-obesity effects are observed.

Although few studies mentioned adverse effects, it should be noted that many serious adverse events which would have stopped a trial of a pharmaceutical agent would likely not have been identified by the authors’ search methods. Moreover, important safety issues including significant adverse events or supplement-drug interactions relevant to many clinical populations may not be fully addressed by the trials available for review.

CONCLUSION

Compliance with conventional weight-management programs, which often include increasing energy expenditure via physical activity, is low. It is not surprising to see the marketing of many new dietary slimming aids aimed at satisfying the need for palatable (as well as safe, effective, and therapeutic) options. In accord with this approach there are numerous investigations on the effectiveness of medicinal plants as natural supplements to reduce body weight. In this paper a variety of herbal supplements had beneficial effects on obesity especially compounds containing ephedra, CQ, ginseng, bitter melon (Momordica charantia), and zingiber. Most of the introduced herbals (Tables 1 and 2) have also been shown to have antioxidant effects, and with regard to the role of oxidative stress in the pathophysiology of some diseases and conditions, their further positive effects may be very promising[86-95]. Attention to these natural compounds and further work on the isolation and characterization of their constituents is highly recommended.

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