What I feared from my last blog has come true. It
looks as if athletes are going to be “forced” by media (or political!) pressure
to reveal their blood passport data – well every athlete who is successful in a
high profile sport at least. In this context I was interviewed after Paula
Radcliffe on Sky News this afternoon. When I finished the interviewer thanked me,
but said it was all very complex. Such a response would normally indicate I had failed as a
science communicator. In this case I think I succeeded in getting my point across.
Interpreting anomalous athlete biological passport data is non trivial. That is
why it requires three experts to agree in a blind test (not knowing who the
athlete is). Simple analysis can work on large data sets to indicate the potential
scale of a doping problem. It can’t be done to scapegoat an individual.
Wednesday, 9 September 2015
Thursday, 20 August 2015
Doping at the World Athletics Championships – part 1
My
title indicates that I think these championships might take up more than one of
my blogs! Indeed the Sunday Times/IAAF doping story has already messed up my
holiday. I was pestered by well meaning journalists while visiting Yorkshire.
Fortunately I was for the most past saved by dodgy mobile phone signals and an
absence of Wifi. I did, however, make an exception to talk to Radio 5 live
Drive and Radio 4 pm in the BBC radio car parked in the local pub car park.
What could be more surreal?
It
has been hard commenting on the leaks given the fact that the various
protagonists (IAAF and the Sunday Times/ ARD/WDR) have access to the data but have released only a very limited
amount into the public domain. The IAAF has indicated they will eventually
publish a “prevalence study” sometime in the future. Whether this will go so
far as to make comparisons between countries and whether it will also be
possible to compare individual sporting events remains to be seen. These of
course are the highlights of the leaks, but realistically might be excluded in
an academic type report.
So
what can be said and how does it relate to the upcoming World Athletics
Championships in Beijing? Well, starting with a selfish note, I am pleased that
the 1500m final in the women’s 2005 World Athletics championships is finally
getting the “recognition” it deserves [1]. In the opening pages of my book I
note that, far more than Ben Johnson’s 100m run in the Seoul Olympics, this
race deserved the moniker of the dirtiest race in history [2]. My comment that
the first five athletes to cross the line were alter found guilty of doping
(admittedly in later tests) has now been backed up by anomalous blood readings
taken at the time of the events.
It
is worth noting that the winning time in this infamous race was over a second
slower slower than when the clean athlete, Kelly Holmes, won the 1500m Olympics
title a year earlier. This brings me to my first substantive point. An
anomalous blood reading does not mean someone is necessarily doping. And even
if they are doping it does not mean that they won the race because they were
doping. Although there is good evidence in the scientific literature that increasing
your total haemoglobin levels increases athletic performance, there are
sparingly few results in elite athletes (where performance effects of ergogenic
aids naturally become smaller in size). Even the studies that have been done rarely
use a proper randomised placebo controlled design. There is no control for the
placebo effect. The importance of this cannot be underestimated; a placebo effect
is likely to be doubly powerful when taking a banned substance as these are
assumed to be especially powerful. Interestingly a recent randomised blind
trial on elite cyclists surprisingly showed no effect of altitude training and
suggested previous positive results might be mostly down to placebo [3]. “Unfortunately” it will be almost impossible
to do a similar study using EPO or blood doping due to ethical constraints
surrounding giving people potentially harmful drugs. Worse still the definitive
study would involve giving someone the drug and actively telling them they are
getting a placebo [4]; even using microdoses of EPO this would be a real ethical
minefield.
My
second substantive point relates to the success, or not, of the blood passport
program introduced in athletics by the IAAF in 2009. Clearly this has resulted
in a significant number of suspensions. But has it affected the number of
people doping? In cycling there seems to be a clear effect [5]. This was shown
by the drop in the number of cyclists showing abnormally high or low levels of
young red blood cells called reticulocytes (a recent blood transfusion will
likely give a low number and an injection of a high dose of EPO a high number).
The blood doping expert Michael Ashenden was reported in the Sunday Times as
saying that “despite the
introduction of the biological passport, analysis of the data shows nearly 70
athletes with suspicious blood test results still escaped censure” [6]. This my
be so, but it would be very interesting to see his detailed analysis of whether
there was any change at all from 2009-2012.
The
relevant data outlining the effect of blood doping on the performance of elite
athletes is hidden from the average scientist in the secret files of doping
athletes and their coaches. Still my “not too controversial” personal view is
that blood transfusions and high dose EPO genuinely provide a performance
benefit in elite athletes. I am currently less convinced that micro dosing of
EPO, of the type designed to fool the biological passport, is as effective. It is
unlikely to create a situation where a clean athlete cannot win a race against
a doper. It is also possible that just by forcing the athletes to change doping
strategies to avoid detection, you make that doping less effective.
In
the worst-case scenario portrayed by the Sunday Times 30% of successful athletes
had anomalous blood readings and so might have been doping; but this still means
that 70% of athletes with “normal” blood readings managed to beat these dopers.
Doping is best seen as one part of a complex set of factors that lead to a gold
medal. It is only occasionally in sport that we see situations where it is
inconceivable that a clean athlete could beat a doper – the most notable being
the period in the 1970s and 1980s when female athletes were dosing with large
amounts of anabolic steroids. The Tour de France in the Armstrong years may
well be another example.
My
final point relates to one I was questioned by on BBC radio recently. Should
athletes reveal their own passport data? Even the athletes themselves are
divided on this [7, 8]. But I feel the cat is out of the bag now. Anyone with a
normal score is going to shout it from the rooftops. Those with anomalies will
be shamed for not revealing them – unless they have a really clear explanation
to hand. Anyone not revealing their scores will be assumed to be hiding their
data because they are doping. My major concern is that the internet will fill
up with well-meaning and not so well-meaning amateurs who will be able to
“prove” that someone is doping from their passport score.
We
have seen this effect with performance data in cycling for a number of years
now. The most recent example was the accusations of doping against Chris Froome
in the Tour de France in the complete absence of any analytical doping data [9]
or any intelligence about dodgy practices garnered from fellow team members
[10]. Another example: the UK 400m runner Roger Black is one of those now
calling for athletes to reveal their passport data [7]. Yet I remember him
telling me he was once confronted by a member of the public who said he could
tell he was cheating just by looking at some of the times he had posted. As
Paula Radcliffe [8] said you can never prove you are not doping.
I
suspect blood passport scores such as reticulocyte count, red cell volume and
haemoglobin concentration will soon become as well known to the world of online
sport comment as performance measures such as peak power, VO2 max
and lactate threshold are now. In the conclusion of my book I said “When it comes to making practical and
ethical policy there is a devil in the scientific detail that is absolutely
required if we are to make informed moral and political choices.” In athletics
and doping the time of science is upon us now.
Monday, 20 July 2015
Wheatgrass juice, Channel 4, and blood oxygen – the data says no!
I just did
a piece for Channel 4 on their superfoods program (http://www.channel4.com/programmes/superfoods-the-real-story).
It was looking into the claim that wheatgrass juice improved blood oxygen
content; allegedly this works by increasing the amount of haemoglobin as haem
and chlorophyll look so similar. My incredulity contrasted with the health food
expert who supplied the wheatgrass enema to the presenter. The expert said
there was a lot of scientific evidence that supported her view. There was not
time in the program to give the full account for the reasons for my incredulity
so I thought it worth expanding a bit here in case anyone is interested.
·
Haem is
an iron porphyrin and chlorophyll is a magnesium chlorin. Superficially haem and
chlorophyll appear similar in chemical structure – one of the ideas that led to
Charles Schnabel in the 1930s suggesting wheatgrass could be a superfood.
Proponents today suggest it can increase the amount of haemoglobin in the
blood. However, in the 1930s the structure of proteins was not known. Not only
does chlorophyll contain magnesium rather than iron at its centre, but it has a
long organic side chain. Even if you could replace the magnesium with iron, you
could not put the iron-chlorin into the haemoglobin structure. It just won’t
fit.
· So maybe the chlorophyll provides building
blocks to help us make more haem? In this case wheatgrass juice might increase
haemoglobin by an indirect mechanism? There are a number of problems with this
idea. First there is no evidence that we absorb chlorophyll, whether taken
orally or rectally. Even if we did absorb chlorophyll, we cannot convert a
chlorin into a haem. The pathways are
linked metabolically; plants make haem and chlorophyll from the same organic starting
materials. But we have don’t have the enzymes to make this conversion.
· In contrast to chlorophyll, we do absorb
haem quite efficiently. But we immediately break it down for its iron content,
throwing away the porphyrin cofactor. The result. If you want dietary iron, eat
black pudding not wheatgrass juice.
· Still maybe there is an
unknown mechanism for the wheatgrass effect? Is there any science that supports
the effect of wheatgrass juice increasing blood oxygen content? If there was
good human trial data then we could search for a mechanism. After all gut
bacteria are increasingly seen as important to health. Maybe feeding our gut
chlorophyll has an effect on the body, even if none of that chlorophyll is
absorbed? The problem is that there is no good scientific evidence in human
studies of any blood oxygen, health benefit or sports performance effects. I
looked hard and could find only a very few papers. The first [1] is full of flaws and, as far as
I can see not peer reviewed. However, let’s assume the study was well
conducted. The effects observed (0.26% increase in arterial blood oxygen
saturation) would have no significant physiological benefit; indeed there was
no performance boost reported in this paper.
· If wheatgrass juice really
did increase the number of red blood cells it would be a godsend for many
patients who have anaemia. Who needs epo or blood transfusions if you can just
eat crushed grass? Two papers looked at this effect. The first, a small pilot
study [2], suggested that consuming
about 100 mL of wheat grass juice daily could reduce the need for blood transfusions in
patients with thalassemia major. However, a later, larger study contradicted this [3]. Neither study
was randomised or blinded.
· Lest I be accused of being a
complete cynic there is one study published that holds some promise. In a small
double blinded, placebo controlled trial in ulcerative colitis (inflammatory bowel disease), wwheatgrass seemed to have
some beneficial effects [4]. This study was conducted in 2002 and, as far as I
can tell, has not been followed up. But at least it has the benefit of not
straining credulity – the chlorophyll is suggesting to act where we know it
goes – the gut.
In short wheatgrass juice is no superfood. At least not when it comes to
increasing the number of red blood cells. There is no reason for WADA to put it
on the sporting banned list or develop chlorophyll anti-doping tests.
Epo and doping accusations in the Tour de France – the numbers never lie (or do they?)
I was
struck by the vehemance of the current anti-Froome accusations. So I thought I
would add my tuppence worth to this story. First let me nail my colours to the
mast. I have a lot of sympathy with Sir Dave Brailsford when he says “"It is not possible to prove a negative. I
can't," [1].
Sir Dave is referring to the well-known fallacy in
formal logic known as an argumentum ad ignorantiam or “appeal to
ignorance”. This poses that “something is true only because it has not been
proved false, or that something is false only because it has not been proved
true”.
Now there
are some cases where versions of this argument are used by philosophers
(inductive logic relies on it in part). Indeed you cannot prove any future
event true or false until it has happened. Prehistoric man with no knowledge of
physics or astronomy had no definite “proof” that the sun would rise tomorrow
or that walking off a cliff would result in a fatal fall. However, enough
evidence had accumulated from previous life experiences to make these perfectly
reasonable assumptions. Indeed it would be impossible for us to live our lives
without making these kind of inductive “leaps of faith” every day.
Something
ought to go without saying given the scientific literature, but clearly it
needs repeating ad infinitum. Doping allegations based purely on performance
(in this case speed or power data) fall well short of the strong evidence
required for inductive reasoning. Power/time data alone can never prove someone
is doping, or even make it probable. If you doubt this please take time to read
carefully the recent article by Hein FM
Lodewijkx “The Epo Fable in Professional Cycling: Facts, Fallacies and
Fabrications” [2].
Not that
the Lodewijkx review does not prove that epo does not improve performance; in fact it
is careful not to say this. Times have continually
improved in the Tour and doping could be one of many factors that can affect racing
times. The devil is in the scientific detail. But it does make salutary reading
for people who assume that numbers alone are a reason for crying foul.
One thing that is needed is a proper randomized trail in elite cyclists
testing whether epo doping “works”. Crucially, it should include accounting for
the likely strong placebo effect (as everyone “knows” epo works – see my
previous blog). The definitive study would include giving cyclists epo when
they were told they were getting placebo. This kind of approach has been very successful
in studies comparing drug and placebo effects on performance following caffeine
administration [3]. However, significant ethical issues would need to be
overcome before any epo study could start. Worse still cyclists would need to
volunteer for a “ban” so it also need an end of career altruistic act.
If such a study were performed, my suspicion is that it would show that
epo microdosing is no more effective than a strong placebo. I suspect blood
transfusions or high dose epo would
outperform placebo, but I doubt those more severe studies could be done. Still
I don’t “know” these answers – as a scientist I just want the studies to be
done (ethics permitting) to find out!
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