OTC diet pill as effective as placebo

I was interested to read an article published in the August edition of the Medical Chronicle, that papers presented at the XI International Congress on Obesity, that was held in Stockholm, Sweden, in July 2010, showed that over-the-counter (OTC) slimming pill ingredients have no more effect that placebo pills.

From feedback received from readers and studies of the effects listed for the various herbal ingredients used in OTC slimming pills in authoritative reference books, such as the Pharmacopoeia, I have long suspected that these pills and potions that promise instant weightloss are a sham. With these new studies reported from the XI Congress of Obesity, additional proof is now accumulating that taking OTC slimming pills is basically a waste of time and money and may expose slimmers to a whole host of negative side-effects.

A vast, lucrative and uncontrolled industry

According to Dr Igho Onakpoya, at the Peninsula Medical School of the Universities of Exeter and Plymouth in the UK, who published the results of one of the above mentioned studies, sales of the unregulated slimming industry globally exceed $13 billion. In Western Europe, more than £900 million are spent on OTC weightloss products by desperate individuals trying to lose weight.

According to Dr Onakpoya, people who suffer from overweight and obesity believe that these sliming products "are a short cut to weightloss and may spend huge sums of money on them, but they may end up disappointed, frustrated and depressed if their weight expectations are not met in the long term." 

The situation is no different in South Africa, where the public enticed by promises of instant, supposedly "safe because these products are natural and herbal" weightloss, spend hard-earned money on OTC slimming pills only to end up disappointed or addicted to the synephrine, caffeine and other addictive ingredients that are often used in these products.

One of the most frustrating aspects of the OTC slimming product market, is that most governments, including the US Food and Drug Administration (FDA) do not regulate weightloss supplements. The same can be said for South Africa. While pharmaceutical products have to produce endless proof of efficacy and safety to be registered by the Medicines Control Council, at present anyone can mix together some herbal extracts and sell them as a super slimming product without any control whatsoever.

The German study

Reports from the XI Congress on Obesity in Stockholm, which was chaired by Prof Stephan Rössner, one of the leading experts in the field of obesity who has also lectured in South Africa, indicate that Dr Thomas Ellrott, of the Institute for Nutrition and Psychology at the Göttingen Medical School in Germany, headed a study to investigate if nine popular slimming supplement ingredients would cause more weightloss than the use of placebo pills (placebo pills are dummy pills that have no physiological effect, but may exert a psychological effect because the patient believes he or she is receiving treatment).

The ingredients used in the study included L-carnitine, polyglucosamine, cabbage powder, guarana seed powder, bean extract, Konjac extract, fibre pills, sodium alginate and selected plant extracts. A group of 189 obese or overweight middle-aged subjects were given packets of placebo (fake) pills or one of the nine supplements for eight weeks and instructed to use these products at doses recommended by the manufacturers. To compensate for the diets that usually accompany OTC slimming pills, the researchers gave the same dietary advice to all the participants in the form of specially prepared package inserts.

The subjects who used the slimming pills lost between 1kg and 2kg during the eight week study, while those using fake or placebo pills lost 1.2kg on average. In other words, the weightloss results achieved by the two groups of subjects did not differ significantly. Ellrott is quoted as saying, "we found that not a single product was any more effective than placebo pills in producing weightloss over the two months of the study, regardless of how it claims to work." 

The UK study

Onakpoya reported on a similar study which reviewed all existing systematic reviews of clinical studies using weightloss supplements, particularly those using nine popular slimming pills ingredients: chromium picolinate, Ephedra, bitter orange extract, CLA (conjugated linoleic acid), guar gum, glucomannan, chitosan and green tea.

Onakpoya said that: "We found no evidence that any of these food supplements studied, is an adequate treatment for reducing body weight." In addition, some of the studies found that such weightloss products caused negative side-effects.

The bottom line

These new studies need to be expanded to include all the weird and wonderful ingredients that are used in OTC slimming products, so that we can provide the public with adequate proof and warnings not to be duped and not to use such products. Hopefully one day legislative authorities such as the FDA in America and our own Health Department will take steps to control the sale of these potentially harmful pills and potions that promise the earth to frantic individuals who want to lose weight, and produce no more than the so-called 'placebo effect'.

The latter effect is a well known phenomenon that occurs when people believe that the treatment they are receiving (in the form of pills or drops or injections, etc), is the real thing and will effect a cure or produce a result. Subjects using placebo pills often experience a small positive reaction (like the average weightloss of 1.2kg recorded in the German study), possibly as a result of psychological factors. For an actual treatment like a slimming pill to be declared effective, that slimming pill must produce an effect that is significantly greater than the placebo effect. None of the OTC slimming products tested in the German study showed better results than the fake pills.

These reports from the XI Congress on Obesity, once again indicate that individuals who need or want to lose weight should avoid taking OTC slimming products (no matter how beguiling their ads and promises are) and should rather spend their money on a well balanced slimming diet and membership of a good gym or Walk for Life.

- (Dr IV van Heerden, DietDoc, August 2010)

Any questions? Ask DietDoc


AOL Health 2010. Study: Popular drugstore slimming supplements do nothing to boost weight loss.
ScienceDaily, 2010. No evidence that popular slimming supplements facilitate weight los, new research finds. July 14, 2010
Medical Chronicle. 2010. Slimming supplements ‘useless’. Medical Chronicle, August 2010, p.3.

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