MD, PhD, FMedSci, FSB, FRCP, FRCPEd

obesity

Pyruvate, a ketone and an alpha-keto acid, occurs naturally in the body when glucose is converted into energy. It is part of the Krebs cycle, the complex chain of reactions in which nutrients are metabolised to provide energy. High doses of pyruvate seem to stimulate the breakdown of fat in the body. It is therefore not surprising that pyruvate is used in all sorts of slimming aids; and if the advertising for ‘fat burners’ is to be believed, pyruvate is just the ticket for the desperate slimmer.

One such product advertisement, for instance, claims that sodium pyruvate and potassium pyruvate, which can act as a stimulant for the metabolism, adding to the thermogenesis process. Pyruvates have been found in studies to reduced the storage of fat in the body and convert the food source into calories which are then burned off in the production of heat. In one study, rats were injected with three fat burners, including pyruvates, and the rats given the pyruvates burned the greatest amount of fat by increasing the rat’s resting metabolic rate. With the elevated resting metabolic rate, the body burned more fat in individuals, which makes pyruvate an excellent source for weight maintenance.

So, maybe pyruvate works for rats – but does it really help those of us who would like to lose a few kilos? Some studies seem to say so, but others don’t. What do we conclude? There can only be one solution: we need a systematic review of the totality of the available trial evidence – and you probably guessed it: we have just published such an article.

The objective of our systematic review was to examine the efficacy of pyruvate in reducing body weight. Extensive literature searches identifies 9 RCTs of which 6 were met our inclusion criteria. All had methodological weaknesses. The meta-analysis revealed a statistically significant difference of 0.72 kg in body weight with pyruvate compared to placebo. The magnitude of the effect is small, and its clinical relevance is therefore uncertain. Adverse events included gas, bloating, diarrhoea, and increase in low-density lipoprotein cholesterol.

Our conclusion: The evidence from randomized clinical trials does not convincingly show that pyruvate is efficacious in reducing body weight. Limited evidence exists about the safety of pyruvate. Future trials involving the use of this supplement should be more rigorous and better reported.

Pyruvate supplements are popular; people who want to lose weight are misled into believing that they are effective. Bodybuilders as well as other athletes tend to take them because pyruvate is claimed to reduce body fat and enhance the ability to use energy more efficiently. None of these assumptions is based on sound evidence. Regardless of the evidence, a whole industry is exploiting the gullible and doing very well on it.

As these ‘fat burners’ are by no means cheap, I recommend a more efficient and more economical method for normalising body weight: eat a little less and move a bit more - I know it’s naff, but it works!

It hardly is a secret: we have a growing problem with obesity. Worldwide it is predicted to cause millions of premature deaths – unless, of course, we come up with a safe and effective treatment that patients find acceptable.

Many herbal remedies are being promoted as the solution to this serious problem. My team looked at the evidence for such treatments in much detail. Sadly the results were less than impressive.

But now, there seems to be new hope! Two recent studies of a specific herbal mixture report amazingly good results – or are they perhaps too good to be true?

Stern JS, Peerson J, Mishra AT, Sadasiva Rao MV and Rajeswari KP from the Department of Nutrition and the Department of Internal Medicine, University of California Davis, have just published an RCT in 60 subjects with body mass index (BMI) between 30 and 40 kg/square meter. Participants received either 400 mg herbal capsules with extracts from Sphaeranthus indicus and Garcinia mangostana or 400 mg placebo capsules twice daily. During the study period, participants consumed a standard diet (2,000 kcal per day) and walked 30 min 5 days per week.

After 8 weeks of this treatment, significant reductions in body weight (3.7 kg), BMI (1.6 kg/m2), and waist circumference (5.4 cm) were observed in the herbal group compared with placebo. Additionally, a significant increase in serum adiponectin concentration was found in the herbal group versus placebo. Adverse events were mild and were equally distributed between the two groups.

The authors’ conclusion leave no doubt: Supplementation with the herbal blend resulted in a greater degree of weight loss than placebo over 8 weeks.

As our own review had suggested that extracts of Garcinia cause small short-term weight reductions, the results did not come as a complete surprise to me. What did strike me as odd, however, was the fact that almost simultaneously another article was published. It was authored by Stern JS, Peerson J, Mishra AT, Mathukumalli VS and Konda PR from the Department of Nutrition, University of California-Davis, and it reported the pooled data from the above plus another, similarly designed trial.

The two studies together enrolled 100 patients who were treated either with the same herbal formula or with placebo. All subjects received 2000 kcal/day throughout the study and walked 5 days a week for 30 min. The primary outcome was the reduction in body weight. Secondary outcomes were reductions in BMI and in waist and hip circumference. Serum glycaemic, lipid, and adiponectin levels were also measured. Ninety-five subjects completed the trials, and the data from these two studies were pooled and analysed.

At study conclusion (8 weeks), statistically significant reductions in body weight (5.2 kg), BMI (2.2 kg/m2), as well as waist (11.9 cm) and hip circumferences (6.3 cm) were observed in the pooled herbal groups compared with placebo. A significant increase in serum adiponectin concentration was also found in the herbal groups versus placebo at study conclusion along with reductions in fasting blood glucose (12.2%), cholesterol (13.8%), and triglyceride (41.6%) concentrations. No changes were seen across organ function panels, multiple vital signs, and no major adverse events were reported. The minor adverse events were equally distributed between the two groups.

And what should be odd about that? Authors are entitled to pool the data of two of their own trials! Yes, of course, but what confuses me is the fact that the data from the second study of 40 patients cannot be found anywhere. I would have liked to see how it is possible that the results from just 40 more patients (actually just 35 seemed to have been included in the analysis) raise the average weight loss from 3.7 kg in the first RCT to a remarkable 5.2 kg in the two RCTs together. As a rough estimate, this means that, in the second trial, patients who took the herbal mixture must have lost about one kilo per week more than those who were on placebo. If true, this outcome is pretty sensational! It could signal the end of the obesity epidemic. It would also mean that the manufacturer of this herbal wonder mixture stands to earn billions.

Considering the potential importance of these findings, I would also like to know what precisely the Californian researchers’ involvement has been in these two studies. In the second article they state that: The two clinical trials were performed at Alluri Sitarama Raju Academy of Medical Sciences (ASRAM), Eluru, Andhra Pradesh, India from November 2009 to April 2010 (clinical trial registration number: ISRCTN45078827) and from March 2010 to July 2010 (clinical trial registration number: ISRCTN52261953). I find this puzzling.

Moreover, it would be interesting to learn what happened to the following co-authors of the first study: Sadasiva, Rao MV and Rajeswari KP. As authors of the largest of the two trials, I would have thought their names would have to be included in the article reporting the pooled data of the two studies.

Call me sceptical, perhaps even cynical, but I do wonder about trials which seem to beg so many intriguing questions. In case you want to know who funded these studies and who thus stands to make the above-named billions, the answer is provided in the second paper: This work was supported by an unrestricted grant from InterHealth Nutraceuticals Inc., Benicia, CA, to J.S.S.

So, do I think that we have finally identified a safe and effective treatment to combat the worldwide epidemic of obesity? Well….

The developed world is in the middle of a major obesity epidemic. It is predicted to cause millions of premature deaths and billions of dollars, money that would be badly needed elsewhere. The well-known method of eating less and moving more is most efficacious but sadly not very effective, that is to say people do not easily adopt and adhere to it. This is why many experts are searching for a treatment that works and is acceptable to all or at least most patients.

Entrepreneurs of alternative medicine have long jumped on this band waggon. They have learnt that the regulations are lax or non-existent, that consumers are keen to believe anything they tell them and that the opportunities to make a fast buck are thus enormous. Today, they are offering an endless array of treatments which are cleverly marketed, for instance via the Internet.

Since many years, my research team are involved in a programme of assessing the alternative slimming aids mostly through systematic reviews and occasionally also through conducting our own clinical trials. Our published analyses include the following treatments:

Phaseolus vulgaris

Supplements containing conjugated linoleic acid

Green tea

Garcinia extracts

Calcium supplements

Chromium picolinate

Guar gum

Chitosan

Acupuncture

There are, of course, many more but, for most, no evidence exist at all. The treatments listed above have all been submitted to clinical trials. The results show invariably that the outcomes were not convincingly positive: either there were too few data, or there were too many flaws in the studies, or the weight reduction achieved was too small to be clinically relevant.

Our latest systematic review is a good example; its aim was to evaluate the evidence from randomized controlled trials (RCTs) involving the use of the African Bush Mango, Irvingia gabonensis, for body weight reduction in obese and overweight individuals. Three RCTs were identified, and all had major methodological flaws. All RCTs reported statistically significant reductions in body weight and waist circumference favoring I. gabonensis over placebo. They also suggested positive effects of I. gabonensis on blood lipids. Adverse events included headache and insomnia. Despite these apparently positive findings, our conclusions had to be cautious: “Due to the paucity and poor reporting quality of the RCTs, the effect of I. gabonensis on body weight and related parameters are unproven. Therefore, I. gabonensis cannot be recommended as a weight loss aid. Future research in this area should be more rigorous and better reported.”

People who want to loose weight are often extremely desperate and ready to try anything. They are thus easy victims of the irresponsible promises that are being made on the Internet and elsewhere. Despite the overwhelmingly evidence to the contrary, consumers are led to believe that alternative slimming aids are effective. What is more, they are also misled to assume they are risks-free. This latter assumption is false too: apart from the harm done to the patient’s bank account, many alternative slimming aids are associated with side-effects which, in some cases, are  serious and can even include death.

The conclusion from all this is short and simple: alternative slimming aids are bogus.

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