Echinacea: No better than blessings

Back in the sixth century AD, most of Europe was succumbing to the bubonic plague.  One of the first signs of the plague was sneezing, and so as legend has it, Pope Gregory the Great was the first to say “God bless you” when anyone sneezed, presumably as a pre-emptive death rite.

The practice of saying “Bless you” to any and all steternatory reflexes spread across Europe just as quickly as the plague did, and then to other parts of the world where they developed their own local variation (for example, apparently people in Arabic countries say, “Alhamdulillah,” which means, “praise be to God.” Hindus say, “Live!” or “Live well!”).  There were also some superstitious meanings attached.  For example, people can to believe that a sneeze was someone’s soul detaching itself and exiting the body, and saying “Bless you” would stop Satan from stealing their untethered soul (http://goo.gl/znyyuY).

These days, we know that the humble sneeze has nothing to do with detaching souls or the Bubonic Plague, but interestingly, the cultural phenomenon of blessing people every time they sneeze is something that lives on.

While it’s not the only reason people sneeze, we know that the main cause for sneezing, especially at this time of year, is viruses.  There are lots of different home and herbal remedies that people swear by for colds and flus.  I hear about them every winter.  Last year I reviewed the effectiveness for Olive Leaf Extract.  Another popular herbal remedy is Echinacea.

Echinacea is a family of perennial flowering plants which are in the same broad class as sunflowers.  Early botanists gave the flowers the name Echinacea, from the Greek root word is rooted in the Greek word ‘echinos’ because the distinct spiky appearance and feel of the flower heads looks a little like an echidna or hedgehog.

Traditionally, Echinacea products are thought to enhance the action of the white blood cells, which in turn, is supposed to help the body fight off various sorts of infections.  There are many different variations of Echinacea products that are available for consumers, but these vary widely in composition. They contain different extracts from different bits of different Echinacea species which result in vastly different chemical compositions between the products.

So, do Echinacea products work?  Are they worth the money people are spending on them?

As I was poking around the internet today, I came across this article in Natural News.  The article boasted: “Echinacea preparation as effective as Tamiflu in early flu cases in large clinical trial” … “Echinaforce Hotdrink has here been demonstrated as attractive therapy for acute influenza treatment with better safety and comparable efficacy profile to the neuraminidase inhibitor Oseltamivir.” (Oseltamivir is also known as Tamiflu, the gold standard influenza treatment).

That sounded promising, until I looked at the actual paper the article was referencing.  Natural News failed to report the most important paragraph, “This study was sponsored by A. Vogel Bioforce AG, Roggwil, Switzerland, manufacturer of Echinaforce Hotdrink. R. Schoop is an employee of Bioforce AG, and K. Rauš and P. Klein have received honorarium funds from the study sponsor.” [1]  In other words, this journal article was the scientific equivalent of an infomercial.  No particularly independent or trustworthy results there.

What about independent trials into Echinacea?  Do they show any benefit?

Ah, that would be “no”.  Echinacea products have been reviewed several times in the past [2-4] and the same conclusion has been reached every time.  In fact, a Cochrane review (the gold standard of clinical research) was published on the use of Echinacea for the common cold in 2014 [5].  The best that it could say for Echinacea was that there was a weak trend towards benefit for prevention of colds, but there was also a trend towards people dropping out of the study because of side effects.  There was no evidence at all for treating a cold with Echinacea.

In biostatistics lingo, ‘trend’ means there was a small blip one way or another, but it could be entirely related to random chance.

The bottom line is that there’s no strong evidence that Echinacea does anything for a cold or influenza.  In terms of health benefits, taking Echinacea for a cold is equivalent to saying “bless me” whenever you sneeze.  At least blessings don’t cost $15 dollars a bottle.

So when you’re inevitably struck down by the modern plague of common colds this winter, stick to rest, fluids, and some paracetamol.  They’re much more of a blessing than Echinacea supplements.

References

[1]        Raus K, Pleschka S, Klein P, Schoop R, Fisher P. Effect of an Echinacea-Based Hot Drink Versus Oseltamivir in Influenza Treatment: A Randomized, Double-Blind, Double-Dummy, Multicenter, Noninferiority Clinical Trial. Curr Ther Res Clin Exp 2015 Dec;77:66-72.
[2]        Barnes J, Anderson LA, Gibbons S, Phillipson JD. Echinacea species (Echinacea angustifolia (DC.) Hell., Echinacea pallida (Nutt.) Nutt.,Echinacea purpurea (L.) Moench): a review of their chemistry, pharmacology and clinical properties. J Pharm Pharmacol 2005 Aug;57(8):929-54.
[3]        Hart A, Dey P. Echinacea for prevention of the common cold: an illustrative overview of how information from different systematic reviews is summarised on the internet. Preventive medicine 2009 Aug-Sep;49(2-3):78-82.
[4]        Allan GM, Arroll B. Prevention and treatment of the common cold: making sense of the evidence. CMAJ : Canadian Medical Association journal = journal de l’Association medicale canadienne 2014 Feb 18;186(3):190-9.
[5]        Karsch-Volk M, Barrett B, Kiefer D, Bauer R, Ardjomand-Woelkart K, Linde K. Echinacea for preventing and treating the common cold. The Cochrane database of systematic reviews 2014;2:CD000530.

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Olive Leaf Extract – A potential treatment, but not for what you think

Here in Australia, it’s winter. It’s currently warmer in the fridge than it is outside. We’ve just been blasted by a wall of frigid air straight from Antarctica, and much of the south-eastern corner of our continent has snow drifts over parts that not so long ago were baking under the hot Autumn sun. It’s not something we’re used to in Australia.

Of course, now that winter is firmly entrenched, more people are coming to see me with their viral upper respiratory tract infections, better known as ‘colds’. Yes, ’tis the season to be sneezin’!  Over my years of practice, I’ve seen enough people with a cold to last me a thousand winters.

What always fascinates me are the things that people try to use to cure their cold. I think I’ve heard everything over the last decade: garlic, ginger, peppermint, chicken soup, honey, tea, honey mixed with lemon mixed with tea, or honey mixed with lemon mixed cayenne pepper mixed with tea.   Some people rub Vicks on their feet. Other people douse their pillows in eucalyptus oil.

Another common recommendation that gets around the grape vine and social media is olive leaf extract, used in traditional ‘medicine’ for thousands of years, and those witch-doctors and shamans can’t all be wrong.

One published review described the ‘science’ of olive leaf extract: “Constituents of the olive tree, Olea europaea, have been studied and utilized in folk medicine for centuries. Olive leaf extract, derived from the leaves of the olive tree, contains phenolic compounds, specifically oleuropein, that have demonstrated potent antimicrobial, antioxidant, and anti-inflammatory activity. Oleuropein and derivatives such as elenolic acid have been shown to be effective in in vitro and animal studies against numerous microorganisms, including retroviruses, coxsackie viruses, influenza, and parainfluenza as well as some bacteria. Research suggests that olive leaf constituents interact with the protein of virus particles and reduce the infectivity and inhibit replication of viruses known to cause colds, influenza, and lower respiratory infection. Olive leaf extract has also been shown to stimulate phagocytosis, thereby enhancing the immune response to viral infection. Anecdotal reports indicate olive leaf extract taken at the onset of cold or flu symptoms prevents or shortens the duration of the disease. For viral sore throats, gargling with olive leaf tea may alleviate symptoms, possibly by decreasing inflammation and viral infectivity.” [1]

It’s always a concern when a supposedly peer reviewed journal allows an article to get through which seriously discusses anecdotal evidence as something worthy of attention. Anecdotal evidence is the weakest level of evidence possible. Anecdotal evidence is essentially just stories and opinion [2]. There’s anecdotal evidence for the Tooth Fairy. The other ‘evidence’ that this review describes is from in vitro studies, which are trials in test tubes not in people. In vitro evidence is only helpful in a general sense. Just because a reaction happens in a test tube or petri dish doesn’t mean that it will happen in a real life human being.

So then, do the claims for olive leaf extract stand up to the rigors of modern scientific enquiry or is it like every other cold and flu ‘remedy’ – just another individualised mythology?

Being sceptical, I wanted to find out. So I searched through the published medical literature for quality clinical trials that studied olive leaf extract in humans, and I found only six trials. Interestingly, all of the trials studying olive leaf extract weren’t looking at its effect on immune function but on cholesterol and blood sugar control, blood pressure, and oxidative stress.

In 2009, Kendall et al published a single-centre, randomized, single-blinded, prospective pilot comparison of the effect of dietary supplementation with olive leaf extract on the markers of oxidative stress in 45 healthy young adult volunteers. They found that olive leaf extract had no effect on oxidative stress compared to the control group [3].

Susalit et al (2011) published a double-blind, randomized, parallel and active-controlled clinical study looking at the tolerability, cholesterol-lowering and anti-hypertensive effect of Olive leaf extract in comparison with Captopril (a common blood pressure medication) in patients with early hypertension. After 8 weeks of treatment, there were similar reductions in blood pressure in both the olive leaf extract and the blood pressure pill groups. There was a significant drop in triglyceride levels in the olive leaf extract group, but not in Captopril group [4].

Wainstein et al (2012) performed a randomized controlled trial on 79 adults with non-insulin dependent diabetes, comparing a single 500mg dose of olive leaf extract with placebo over 14 weeks. They measured the HbA1c (a surrogate measurement of the average blood sugar over a three month period) and plasma insulin levels. They also did studies in rats to study the mechanism of action of the olive leaf extract. In the human trials, the subjects treated with olive leaf extract exhibited significantly lower HbA1c and fasting plasma insulin levels. This effect was thought to be reflected in the rat study which suggested that olive leaf extract reduced the digestion and absorption of starch from the intestines [5].

de Bock et al (2013) did a randomized, double-blinded, placebo-controlled, crossover trial on 46 patients in New Zealand, over a 30 week period. The participants were middle aged and overweight. The researchers were primarily studying insulin sensitivity but they also looked at glucose and insulin profiles, cytokines, lipid profile, body composition, 24-hour ambulatory blood pressure, and carotid intima-media thickness. The olive leaf extract group had a statistically significant improvement in insulin sensitivity and responsiveness of the pancreatic β-cell. Interestingly, the olive leaf extract supplementation improved some inflammatory markers, but not others, and made no difference to the patients lipid profile, blood pressure, body composition (their body fatness), carotid intima-media thickness (a risk predictor of cardiovascular disease), or liver function [6].

For completeness, de Bock lead another trial, also published in 2013, although this trial was more a study of the absorption of the compounds in olive leaf extract than a study of their effects [7]. There was a 1996 Belgian study which was written in French. I’m not very good with French, but according to the English abstract, there was no difference between the olive leaf extract and placebo in terms of blood pressure and blood sugar levels [8].

Reconciling the research on olive leaf extract makes for an interesting narrative. There are a couple of really strong, methodologically robust trials on olive leaf extract, and with positive results in favour of it. However, I can count them on one hand, and while the results are encouraging for proponents of olive leaf extract, there needs to be a lot more research before those claims can be made with certainty. And in contrast to its usual selling points, those positive effects for olive leaf extract were for blood sugar control, not the prevention or treatment of viral illnesses.

The bottom line – olive leaf extract may one day prove to be a useful herbal supplement, but there’s not enough clinical evidence to support it at the present moment. And there’s certainly no evidence that olive leaf extract will do anything for your viral upper respiratory tract infections.

So next time you get a cold, don’t bother spending money on olive leaf extract. Have a couple of paracetamol, a long hot shower and a good rest.

And if symptoms persist, don’t forget to see your GP.

References

[1]        Roxas M, Jurenka J. Colds and influenza: a review of diagnosis and conventional, botanical, and nutritional considerations. Alternative medicine review : a journal of clinical therapeutic 2007 Mar;12(1):25-48.
[2]        Fowler G. Evidence-based practice: Tools and techniques. Systems, settings, people: Workforce development challenges for the alcohol and other drugs field 2001:93-107.
[3]        Kendall M, Batterham M, Obied H, Prenzler PD, Ryan D, Robards K. Zero effect of multiple dosage of olive leaf supplements on urinary biomarkers of oxidative stress in healthy humans. Nutrition 2009 Mar;25(3):270-80.
[4]        Susalit E, Agus N, Effendi I, et al. Olive (Olea europaea) leaf extract effective in patients with stage-1 hypertension: comparison with Captopril. Phytomedicine : international journal of phytotherapy and phytopharmacology 2011 Feb 15;18(4):251-8.
[5]        Wainstein J, Ganz T, Boaz M, et al. Olive leaf extract as a hypoglycemic agent in both human diabetic subjects and in rats. Journal of medicinal food 2012 Jul;15(7):605-10.
[6]        de Bock M, Derraik JG, Brennan CM, et al. Olive (Olea europaea L.) leaf polyphenols improve insulin sensitivity in middle-aged overweight men: a randomized, placebo-controlled, crossover trial. PloS one 2013;8(3):e57622.
[7]        de Bock M, Thorstensen EB, Derraik JG, Henderson HV, Hofman PL, Cutfield WS. Human absorption and metabolism of oleuropein and hydroxytyrosol ingested as olive (Olea europaea L.) leaf extract. Molecular nutrition & food research 2013 Nov;57(11):2079-85.
[8]        Cherif S, Rahal N, Haouala M, et al. [A clinical trial of a titrated Olea extract in the treatment of essential arterial hypertension]. Journal de pharmacie de Belgique 1996 Mar-Apr;51(2):69-71.

Dr Caroline Leaf and the 98 Percent Myth

Dr Caroline Leaf believes that nearly all our diseases come from our thoughts.

Dr Caroline Leaf believes that nearly all our diseases come from our thoughts.

In the hustle and bustle of daily life, most people wouldn’t stop to consider what makes people sick.  In my profession, I get a front row seat.

In the average week, I get to see a number of different things.  Mostly “coughs, colds and sore holes” as the saying goes, although there are some rarer things too.  And sometimes, people present with problems that aren’t for the faint of heart (or stomach – beware of nail guns is all I can say).

Normally, the statistics of who comes in with what doesn’t make it beyond the desk of the academic or health bureaucrat.  The numbers aren’t as important as the people they represent.

But to Dr Caroline Leaf, Communication Pathologist and self-titled Cognitive Neuroscientist, the numbers are all important.  To support her theory of toxic thoughts, Dr Leaf has stated that “75 to 98% of mental and physical (and behavioural) illness comes from one’s thought life” [1: p37-38].  She has repeated that statement on her website, on Facebook, and at seminars.

As someone with a front row seat to the illnesses people have, I found such a statement perplexing.  In the average week, I don’t see anywhere near that number.  In general practices around Australia, the number of presentations for psychological illnesses is only about eight percent [2].

But Australian general practice is a small portion of medicine compared to the world’s total health burden.  Perhaps the global picture might be different?  The World Health Organization, the global authority on global health, published statistics in November 2013 on the global DALY statistics [3] (a DALY is a Disability Adjusted Life Year).  According to the WHO, all Mental and Behavioural Disorders accounted for only 7.2% of the global disease burden.

You don’t need a statistics degree to know that seven percent is a long way from seventy-five percent (and even further from 98%).

Perhaps a large portion of the other ninety-three percent of disease that was classified as physical disease was really caused by toxic thoughts?  Is that possible?  In short: No.

When considered in the global and historical context, the vast majority of illness is related to preventable diseases that are so rare in the modern western world because of generations of high quality public health and medical care.

In a recent peer-reviewed publication, Mara et al state, “At any given time close to half of the urban populations of Africa, Asia, and Latin America have a disease associated with poor sanitation, hygiene, and water.” [4] Bartram and Cairncross write that “While rarely discussed alongside the ‘big three’ attention-seekers of the international public health community—HIV/AIDS, tuberculosis, and malaria—one disease alone kills more young children each year than all three combined. It is diarrhoea, and the key to its control is hygiene, sanitation, and water.” [5] Hunter et al state that, “diarrhoeal disease is the second most common contributor to the disease burden in developing countries (as measured by disability-adjusted life years (DALYs)), and poor-quality drinking water is an important risk factor for diarrhoea.” [6]

Diarrhoeal disease in the developing world – the second most common contributor to disease in these countries, afflicting half of their population – has nothing to do with thought.  It’s related to the provision of toilets and clean running water.

We live in a society that prevents half of our illnesses because of internal plumbing.  Thoughts seem to significantly contribute to disease because most of our potential illness is prevented by our clean water and sewerage systems.  Remove those factors and thought would no longer appear to be so significant.

In the same manner, modern medicine has become so good at preventing diseases that thought may seem to be a major contributor, when in actual fact, most of the work in keeping us all alive has nothing to do with our own thought processes.  Like sanitation and clean water, the population wide practices of vaccination, and health screening such as pap smears, have also significantly reduced the impact of preventable disease.

Around the world, “Recent estimates of the global incidence of disease suggest that communicable diseases account for approximately 19% of global deaths” and that “2.5 million deaths of children annually (are) from vaccine-preventable diseases.” [7] Again, that’s a lot of deaths that are not related to thought life.

Since 1932, vaccinations in Australia have reduced the death rate from vaccine-preventable diseases by 99% [8].  Epidemiological evidence shows that when vaccine rates increase, sickness from communicable diseases decrease [9: Fig 2, p52 & Fig 8, p67].

Population based screening has also lead to a reduction in disease and death, especially in the case of population screening by pap smears for cervical cancer.  Canadian public health has some of the best historical figures on pap smear screening and cervical cancer. In Canada, as the population rate of pap smear screening increased, the death rate of women from cervical cancer decreased.  Overall, pap smear screening decreased the death rate from cervical cancer by 83%, from a peak of 13.5/100,000 in 1952 to only 2.2/100,000 in 2006, despite an increase in the population and at-risk behaviours for HPV infection (the major risk factor for cervical cancer) [10].

And around the world, the other major cause of preventable death is death in childbirth.  The risk of a woman dying in childbirth is a staggering one in six for countries like Afghanistan [11] which is the same as your odds playing Russian Roulette.  That’s compared to a maternal death rate of one in 30,000 in countries like Sweden.  The marked disparity is not related to the thought life of Afghani women in labour.  Countries that have a low maternal death rate all have professional midwifery care at birth.  Further improvements occur because of better access to hospital care, use of antibiotics, better surgical techniques, and universal access to the health system [11].  Again, unless one’s thought life directly changes the odds of a midwife appearing to help you deliver your baby, toxic thoughts are irrelevant as a cause of illness and death.

Unfortunately for Dr Leaf, her statement that “75 to 98 percent of mental, physical and behavioural illnesses come from toxic thoughts” is a myth, a gross exaggeration of the association of stress and illness.

In the global and historical context of human health, the majority of illness is caused by infectious disease, driven by a lack of infrastructure, public health programs and nursing and medical care.  To us in the wealthy, resource-rich western world, it may seem that our thought life has a significant effect on our health.  That’s only because we have midwives, hospitals, public health programs and internal plumbing, which stop the majority of death and disease before they have a chance to start.

Don’t worry about toxic thoughts.  Just be grateful for midwives and toilets.

References

1.         Leaf, C.M., Switch On Your Brain : The Key to Peak Happiness, Thinking, and Health. 2013, Baker Books, Grand Rapids, Michigan:

2.         FMRC. Public BEACH data. 2010  [cited 16JUL13]; Available from: <http://sydney.edu.au/medicine/fmrc/beach/data-reports/public%3E.

3.         World Health Organization, GLOBAL HEALTH ESTIMATES SUMMARY TABLES: DALYs by cause, age and sex, GHE_DALY_Global_2000_2011.xls, Editor 2013, World Health Organization,: Geneva, Switzerland.

4.         Mara, D., et al., Sanitation and health. PLoS Med, 2010. 7(11): e1000363 doi: 10.1371/journal.pmed.1000363

5.         Bartram, J. and Cairncross, S., Hygiene, sanitation, and water: forgotten foundations of health. PLoS Med, 2010. 7(11): e1000367 doi: 10.1371/journal.pmed.1000367

6.         Hunter, P.R., et al., Water supply and health. PLoS Med, 2010. 7(11): e1000361 doi: 10.1371/journal.pmed.1000361

7.         De Cock, K.M., et al., The new global health. Emerg Infect Dis, 2013. 19(8): 1192-7 doi: 10.3201/eid1908.130121

8.         Burgess, M., Immunisation: A public health success. NSW Public Health Bulletin, 2003. 14(1-2): 1-5

9.         Immunise Australia, Myths and Realities. Responding to arguments against vaccination, A guide for providers. 5th ed. 2013, Commonwealth of Australia, Department of Health and Ageing, Canberra:

10.       Dickinson, J.A., et al., Reduced cervical cancer incidence and mortality in Canada: national data from 1932 to 2006. BMC Public Health, 2012. 12: 992 doi: 10.1186/1471-2458-12-992

11.       Ronsmans, C., et al., Maternal mortality: who, when, where, and why. Lancet, 2006. 368(9542): 1189-200 doi: 10.1016/S0140-6736(06)69380-X