Tag Archives: placebo

Science or Snake Oil: do skinny teas boost weight loss?

The Conversation

File 20171212 9383 1e2tlrz.jpg?ixlib=rb 1.1
‘Skinny teas’ might not have any properties to help you lose weight, but they might remind you you’re on a diet. from http://www.shutterstock.com

Clare Collins, University of Newcastle

Weight loss teas are becoming common, with advertisements claiming dramatic results often appearing online. Do the big promises match the results, or do they only match the price tag?

A search of the medical research database pubmed found there are no studies specifically on the use of “slimming teas” for weight loss, but there are studies on green and black tea.

One review of five research trials compared changes in body weight in more than 300 adults at high risk of type 2 diabetes and heart disease. They gave people either green tea, a fermented tea called Puehr or tea extracts and compared the weight change to people who were given either placebo (non-active) tea extracts or no tea at all.

They found that in the group of people who had the most risk factors for type 2 diabetes and heart disease, and who also ate more healthy foods and exercised more, those having the tea or tea extracts had a weight reduction of about 4kg. Interestingly, in the group who were not given healthy lifestyle advice and who did not have many risk factors, the average weight loss was only about 350 grams.


Read more – Health Check: six tips for losing weight without fad diets


These results suggest most of the weight loss was due to the impact of following the healthy lifestyle advice, and that there may have been some extra motivation to stick to that advice among those who were at high risk of other health problems.

An analysis of six studies examined the effect of tea mixtures that contain added catechins (a chemical compound found in tea that have a bitter flavour) and caffeine or caffeine-only supplements on the body’s energy expenditure. They found both significantly increased the amount of energy the body burns over the day, by approximately 5%. That may not sound like much, but it’s equivalent to about 430 kilojoules per day, or the kilojoules in a medium banana.

In another review of the effects of green tea and added tea extracts on body weight regulation, consuming green tea with the tea extract added was associated with a 1.3 kilogram greater weight loss compared to not consuming them over about three months.

Slimming teas can have herbal tea components, herbal extracts or other additives mixed in with the tea. There’s limited good quality research on the effectiveness of these compounds, although some have been around for decades. But there has been a case report of heart failure triggered from using a herbal weight loss tea that was thought to have illegally contained weight loss drugs known to cause heart problems, so caution must be exercised.

It’s important to look at what’s in the tea you’re drinking.
from www.shutterstock.com

Read more – Health Check: what’s the best diet for weight loss?


Botanical compounds that might be added to slimming tea include the following, so check the label:

  1. Senna, a laxative used to treat constipation;
  2. Valerian root, which has some evidence that it may improve sleep quality;
  3. Roots of the burdock plant, which are thought to contain chemicals that act as a diuretic (and increase urine production);
  4. Yerba mate, a plant common in South America. The leaves are used to make a drink high in polyphenols, a group of compounds found in plants that help the body defend itself against disease. Yerba mate also contains caffeine, so it has a stimulatory effect similar to coffee. A recent review suggests it may be helpful in lowering blood cholesterol levels;
  5. Dandelion leaf contains chemicals thought to have a diuretic effect, but there’s no strong evidence to support this effect;
  6. Celery seed can be used as a spice or flavouring, the active ingredient apiole has been thought to have anti-cancer effects (in mice); and
  7. Calendula flowers are edible and a review of their medicinal use through out history found potential wound healing and anti-swelling properties.

As long as you do not have any sensitivities or a chemical intolerance to slimming tea components, they might have a powerful placebo effect and act as a timely reminder to stick to a weight loss diet. Interestingly, the placebo effect is supported by evidence.

While the price of slimming teas vary, check the small print for disclaimers before you part with your money. They might read something like:

For maximum health benefits this product should be consumed in conjunction with a low kilojoule diet and daily exercise, individual results may vary.

The ConversationThink about whether you get better value from A$30+ dollars worth of weight loss tea or from buying a regular box of green or black tea, and spending the price difference on buying more fruits and vegetables. The research evidence indicates higher intakes of fruit and vegetables are associated with a lower risk of weight gain, heart disease, type 2 diabetes, some specific types of cancer and age-related health decline.

Clare Collins, Professor in Nutrition and Dietetics, University of Newcastle

This article was originally published on The Conversation. (Reblogged by permission). Read the original article.

Leave a comment

Filed under Reblogs

New evidence gives supporters of chiropractic a headache

The Conversation

Michael Vagg, Deakin University

A paper was published and much discussed online recently, which demonstrates all the problems that I – and other critics – have with the way research is done and interpreted in the world of chiropractic.

The study looked at the effect of chiropractic neck manipulation on people who have migraines.

On the face of it, the article concerned looks like a pretty fair and well conducted study. Despite the methodological difficulties of randomisation and blinding of participants with manual therapies, a genuine effort was made as part of the study design to allow for this.

The trial was a three-armed study comparing chiropractic spinal manipulation (CMST) with a sham manual therapy and a group who continued with their usual care.

Although the deliverers of the manual therapy would know what they were providing, a level of blinding to treatment allocation was possible. It was refreshing to see as well that they had checked to confirm that the blinding of subjects was maintained throughout the study. This is extremely important in assessing the validity of a study, and as the authors point out

The importance of our successful blinding is emphasized by the fact that all previous manual-therapy RCTs on headache lack placebo._

The outcome measures chosen were reasonably fair and representative of the group studied. The statistical analysis was conventional enough. They had performed power calculations using a reasonable comparator, which again increases confidence in the validity of the results and shows they were taking the methodology seriously.

The robustness of the methodology is likely the reason it was included in the European Journal of Neurology – a solid, second-tier journal with a credible reputation.

I would not quibble with the summary of their conclusion, published in the paper’s abstract, that said:

It is possible to conduct a manual-therapy RCT with concealed placebo. The effect of CSMT observed in our study is probably due to a placebo response.

This is the correct scientific interpretation of the data. If it was a drug trial, we would conclude there was no pharmacologically relevant effect within the parameters shown, and it would be considered a negative study.

How very different then is the analysis of the same study by chiropractors. The Chiropractors’ Association of Australia (CAA) mentioned it in their press release titled saying “chiropractors welcome latest evidence of headaches”. The relevant quote is:

A paper published in the European Journal of Neurology in September 2016 was the latest in a series of papers to confirm the effectiveness of chiropractic health care in treating people with migraines. The study of 104 people in Norway found that Migraine symptoms were substantially reduced as a result of chiropractic treatment.

Critical reporting of this study, such as found on the website of the American Council on Science and Health, throws up some interesting conversations and interpretations in the comments section.

While I don’t generally read online comment sections (apart from this column naturally) it’s worth making the effort in this particular case. The author of that piece has made the same basic epidemiological arguments as I have above, and come to the correct conclusion that it is a negative study.

One of the commenters accuses the author of deliberate bias and makes the following piquant observation:

To show how much spin this “article” has the title could have been: Have a Migraine? Skip the meds, sham and Gonstead CSMT both effective. more than medical care.

This commenter appears to be making the same error of interpretation as the CAA. The point of a three-armed study is to differentiate between the effect of any intervention in the study (due to placebo responses) and the improvement due to simply being observed in an artificial situation (known as the Hawthorne effect).

If a treatment is genuinely efficacious, one expects to see three divergent curves with: a minor improvement in the no-intervention group; a larger improvement in the sham intervention group; and a clearly larger improvement in the true intervention group.

A treatment which lacks effectiveness will produce results in which the two intervention groups are indistinguishable. That is exactly what this study returned. Observe the graphs for yourself.

The graphs that tell the story. European Journal of Neurology

Note carefully that the authors of the original study are careful to claim the only conclusion that can be drawn is that it is feasible to conduct a manual therapy study in a single-blinded fashion.

They made no claims about the efficacy of the intervention apart from the fact it was equivalent to sham, and in fact are explicit about the fact they believe the treatment effects were all placebo. Outright claiming the opposite is a new peak of disingenuousness for supporters of chiropractic.

Another characteristic of treatments which do not have efficacy is that the more rigorous the study, the more the claimed effect disappears into the statistical noise. To be definitive about a lack of efficacy, a much larger study would be needed.

The results above would not inspire me to spend a couple of million dollars on a study with 200 people in every arm. Results like this over the years have killed off hundreds of medications which were being developed by Big Pharma.

Academic chiropractors are in the invidious position of trying to establish that an ideologically-based treatment system has a scientific basis. They should be careful what they wish for when conducting rigorous studies, as they may find their fondest beliefs being dashed on the rocks of reality.

The ConversationMichael Vagg, Clinical Senior Lecturer at Deakin University School of Medicine & Pain Specialist, Deakin University

This article was originally published on The Conversation. (Reblogged by permission). Read the original article.

Leave a comment

Filed under Reblogs

2014, a Bad Year for Homoeopathy

The Conversation
By Ian Musgrave

This has been a bad year for homoeopathy, first there was the Draft Information Paper on Homoeopathy from the NHMRC, which concluded there was no reliable evidence for the use of homoeopathy in the treatment of the 61 health conditions looked at. Then a homoeopathic remedy manufacturer left the North American market due to law suites over the ineffectiveness of their products, then the Federal Court has found that Homeopathy Plus! was engaged in misleading conduct over its homoeopathic “vaccines”

Quoting from the ACCC website “…[Homeopathy Plus!] engaged in misleading and deceptive conduct and made false and misleading representations to the effect that there was an adequate foundation in medical science for the statement that homoeopathic treatments are a safe and effective alternative to the whooping cough vaccine, when in fact no such foundation exists..”

However, this is not a one-way street. Complementary Medicines Australia has claimed, 6 months after the public consultation process had closed, that the NHMRC process was flawed. In the august publication Food Navigator Asia it was claimed to be “fatally flawed”.

What coffee diluted homeopathically looks like. Ian Musgrave

Before we examine these claims, let me remind you that homoeopathy is based on two principles “like cures like” and extreme dilution, in most cases to levels so dilute that there is almost no chance of a single remaining molecule of original compound being present in the remedy. Thus caffeine diluted 1 in a hundred 30 times is used to treat insomnia and Uranium nitrate diluted 1 in a hundred 30 times is used to treat diabetes.

In the latter case it is fortunate at no uranium will actually be present, as uranium nitrate causes kidney failure. In uranium nitrate-induced kidney failure some glucose turns up in the urine, as the kidneys ability to reabsorb it is damaged. This is completely unlike what happens in diabetes, where high blood glucose overwhelms the kidneys capacity to reabsorb it (in uranium nitrate toxicity blood glucose is not elevated so it is not “like” diabetes at all). Thus the rationale for homoeopathic treatment is flawed at many levels.

But back to the draft report of the NHMRC’s review of homoeopathy. This represents the largest and most extensive recent review of homoeopathy research. The review looked at both systematic reviews of the use of homoeopathy in 61 heath conditions and submissions on behalf of interested parties, which contained a mix of systematic reviews and individual randomised controlled trials. All submissions and papers were carefully evaluated against strict criteria recognised internationally for this type of review. The Australasian Cochrane Centre independently reviewed the overview report to ensure that it was valid and high quality.

To remind you, the review found there was no good evidence that homeopathy was effective for any of the 61 medical conditions considered. In some cases, there was clear evidence that homoeopathy was ineffective; in others the evidence base was too weak to give a clear result. These findings are in concert with other large reviews of homoeopathy. Let’s look at the claimed “flaws”.

There was no adequate explanation of why randomised controlled trials (RCTs) were excluded.

They were not excluded. The main review focused on systematic reviews, which included randomised controlled trials (and other types of high level evidence). This is the best way to compare multiple studies. Randomised controlled trials are considered the highest level of evidence, but the results of a single randomised controlled trial may be misleading for many reasons.

Chance is one, if a therapy has no actual effect,by chance alone you will find some studies that appear to show an effect.

Thus it is far better to compare as many high quality trials as possible to get a clearer picture. Randomised trials were not excluded, but an integral part of the evidence through systematic reviews. Randomised controlled trials submitted by stakeholders that were not already part of systematic reviews were considered as well.

While there are limitations to this approach (specifically the most recent research may be excluded), it is widely used in making clinical decisions and in no way invalidates the findings of the report. One of the biggest limitations is that negative findings tend to be under-reported, so that systematic reviews tend to overestimate the effectiveness of a therapy. That homoeopathy cannot pass muster under these conditions is telling.

Three academics invited to comment on the review all broadly agreed there was no high quality evidence recommending homoeopathy for any disorder.

The review excluded too many studies.

Of the 1367 publications considered in the main review, only 60 were finally considered. Not because of anything sinister, but because only those met the review criteria. 374 were duplicate citations, 729 were the wrong study type (not peer-reveiwed, not systematic reviews or metaanalyses, or not looking at controlled trials or high level evidence) or were not looking at the conditions considered in the review or did not report the outcomes (etc. etc.) (see the main review for details).

Of the reports submitted by stakeholders, only a few passed the inclusion criteria or were not already included. Pro tip, if the NHMRC asks you for peer-reviewed systematic reviews and randomised controlled trials in humans, don’t submit books on the life of Hahneman and studies of frogs exposed to thyroxine (yes, I went through the papers).

The review did not consider any publication not in English.

While this excludes some studies, most high quality studies are published in the English language press. As well, the practicalities of translating foreign language papers to ensure there are no complicating errors in translation are avoided. Overall, the impact of this decision on the reliability of the report is marginal at best.

The NHMRC had not appointed a homeopathic expert to the panel.

Assoc Prof Evelin Tiralongo on the NHMRC panel is trained in homeopathic remedies.

The review did not consider animal studies.

These homoeopathic preparations are already in use in humans, so the appropriate studies are ones in humans in the first place. As well, the studies in animals suffer the same flaws as those in humans, too many are of poor quality and many are unable to be interpreted or make claims that cannot be supported. For example, one study submitted to the review that claimed to demonstrate that homoeopathic treatments kill breast cancer cells actually shows that the ethanol diluent is the lethal factor.

Summary

Overall, while there are some limitations to the study, this is a wide ranging, carefully interpreted study. While overall the broad conclusion is that there is no good evidence the homoeopathy being effective in the 61 studied conditions, in at least 13 studies there was good evidence that homoeopathy was ineffective (asthma for example). The results of this study are in broad agreement with previous studies of homoeopathy (see also this, and before you bring up the “Swiss Report” see here and here).

The NHMRC study conclusion that “…the assessment of the evidence from research in humans does not show that homeopathy is effective for treating the range of health conditions considered” cannot be ignored or dismissed.

This article was originally published on The Conversation. (Reblogged with permission). Read the original article.

Leave a comment

Filed under Reblogs

Are pharmacists are trustworthy as they’d like us to believe?

The Conversation

By Michael Vagg, Barwon Health, 12 September 2014

Pharmacists are consistently held up as among the most respected and trusted of professionals. They fulfil an important role within the health professions of being the gatekeepers of medication dispensing and the link between the community and their medication use. For more than one hundred years, there has been a very clear and ethical distinction between doctors (who prescribe medications) and pharmacists (who sell them). That way, the argument goes, doctors have no direct financial interest in drugs they prescribe, and pharmacists have no direct financial interest in recommending any of the drugs on their shelves directly to patients. So far, so good.

There has been a bit of role creep over the years, with calls from some doctors to be allowed to sell their own concoctions directly to their patients, as well as a much more concerted push by pharmacists to play a bigger role in health care, including providing immunisations and health checks direct to consumers. Naturally this is of concern to GPs as such proposals have the potential to fragment primary care even further. Not to mention taking the critical role of diagnosis and putting it into the hands of those who are underqualified, underinsured and undersupported to handle it.

What concerns me particularly is not so much that these health checks will take work away from GPs. If anything I suspect they will increase GPs workloads, sorting out the advice already given to patients by wannabe GP enthusiasts like pharmacists and their associated naturopaths. This month’s Skeptic magazine from Australian Skeptics highlights the problem quite well.

I think it’s time for pharmacists to decide if they want to keep the trust placed in them by the community to give sound advice. If they want to remain a trusted source of advice they need to lift their game and get all the ear candles, homeopathy, magnets, herbs and supplements out of their shops, along with the iridologists and other fairground ‘health professionals’. In short, they need to start acting like they deserve the trust and respect that is accorded them. We have heard nothing of the training and CPD requirements for pharmacists who want to diagnose and treat patients, let alone how they will be insured. I would want to see all this detail before I let my croupy baby or breathless grandmother within a bull’s roar of a pharmacist’s diagnostic skills.

The protectionism involved in the business of running pharmacies is breathtaking. Like dentists, only pharmacists are legally allowed to profit from running pharmacies, and they have defended this with all the bitterness and vitriol you might expect from a group who know they are onto a good thing. Health Minister Peter Dutton seems all for the pharmacists’ ambitions and has been on the media trail vowing not to wind back their protected status.

So it seems the pharmacists will have all they want. I wonder if they deserve it? I hope they take the opportunity to lift their game as a profession and use their protected status to raise standards, not profits. A good place to start would be to stop advertising and selling shonky devices and products that would be considered fraudulent in any other context. Too hard? Then get out of the expanded responsibility game for good.

The ConversationMichael Vagg does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.

This article was originally published on The Conversation. (Republished with permission). Read the original article.

Leave a comment

Filed under Reblogs

The David and Goliath Fallacy

by Tim Harding

 The biblical parable of David and the Goliath is taught to many children throughout the Western world and the Middle East.  Goliath was a huge armoured and weapon-carrying champion, who was defeated by a small shepherd boy using only a slingshot and stone.  This parable is often cited to show how an underdog with ‘right on his side’ can defeat much a more powerful opponent.

Andrea_del_Castagno_002

In some cases, this parable is extended into a logical fallacy that attempts to paint large and powerful organisations as bad or wrong because they are large and powerful.  For example, anti-science advocates often disparagingly refer to ‘Big Pharma’, implying that the pharmaceutical industry is bad, at least in part, because it is big.  Never mind that, in terms of retail sales dollars, the placebo industry (or so-called ‘alternative medicine’) is of a similar order of magnitude these days.  Similar disparagements are made against medical science, the medical profession and even government agencies on the grounds of their size and influence.

The David and Goliath Fallacy takes roughly the following form:

   Premise 1: There is a conflict between two organisations A and B.

   Premise 2: A is much larger and more powerful than B.

   Conclusion: Therefore, A is bad or wrong, compared to B which is good or right.

Like all logical fallacies, this argument is invalid because the conclusion does not necessarily follow from the premises.  Small organisations can be bad and/or wrong; and large organisations can be good and/or right. In some ways, the David and Goliath Fallacy can be viewed as a perverse over-correction of the aphorism ‘Might Makes Right’.

One of the consequences of this fallacy is that claiming underdog status against a more powerful ‘Goliath’ can give moral licence to poor behaviour during conflicts, to create a ‘more even contest’.  For example, small organisations like the so-called Australian Vaccination-skeptics Network frequently make false or unsubstantiated claims, with the lame excuse that they do not have the resources to back up their claims with evidence. The David and Goliath Fallacy has been used during ideological debates in attempts to justify intellectual property theft and even terrorism.

If you find the information on this blog useful, you might like to consider supporting us.

Make a Donation Button

Leave a comment

Filed under Logical fallacies