Sunday, August 06, 2006

Diet Can Elevate Test Results, But How Much Is Unknown

According to Saudan, et al (2006), a diet rich in maize, sugar cane, millet or pineapple can elevate test results designed to show the presence of exogenous steroids.

Does that mean that if Floyd Landis ate a heaping helping of sugarcane after stage 16 he could have triggered a false positive for the IRMS?

Saudan, et al (2006) speculate that such a diet couldn't do such a thing. However they admit that there's much to be learned, and they also admit in their study that diet in experimental subjects was not monitored, logged, etc. So, in other words, the study assumes that there is some increase in dietary 13C but makes no strides to monitor the correlation between intake of certain foods and the degree to which 13C is elevated in tests. As the test was conducted, people who lived in Africa elevated their 13C by as much as 3%, certainly not enough to trigger a false positive.

But it is interesting to note that the % increase in 13C increased linearly the entirety of the time the test subjects were on this Kenyan diet. There's no decay in the increase, even over a 3 month period. Ostensibly, then, if one were on this diet for a year, then one might see a 12% increase in 13C, two years, 24% increase, and so on. The study lends itself to this interpretation.

If Floyd Landis ate somewhat like a Kenyan for three months, consuming some amount of sugarcane and millet, he could have elevated his 13C levels by 3%. That would have put his test results at 30% above test error, still leaving him 5% away from dubious test results. But if he's been eating loads of millet sweetened with sugarcane for a few years, it very well may have put him in false positive territory.

Several questions remain: how much does the intake of *any* amount of exogenous steroids elevate one's testable 13C levels? In other words, how uncommon is it for someone taking any amount of steroids to test as low as Landis did? Another question: how much sugarcane or millet or pineapple would it take to trigger a false positive? Some cyclists are fanatical about their diets, and many aspects of their diets are aspects that have witnesses. If the guy ate millet breakfast lunch and dinner there would be many individuals who could confirm it. Further, what effect does alcohol, a product of fermented sugar, have on the IRMS?

Whil;e the IRMS is a very good test, there are ways a false positive may be arrived at. The ways in which a false positive result is possible seem apparent yet they are poorly understood.

One thing is clear: if I ever get my knee healthy and try to compete at cycling, I'm going to eat lots and lots of millet and pineapple and give myself a natural means of supplementing with androsterone.

Seriously, though, the moral should be that if the UCI wants to test cyclists they should bear the burden of keeping record of each cyclist's diet.

(Short communication: Christophe Saudana, Matthias Kamberb, Giulia Barbatic, Neil Robinsona, Aurélien Desmarcheliera, Patrice Mangina and Martial Saugya. Longitudinal profiling of urinary steroids by gas chromatography/combustion/isotope ratio mass spectrometry: Diet change may result in carbon isotopic variations. Journal of Chromatography B, Volume 831, Issues 1-2 , 2 February 2006, Pages 324-327.)


Blogger A.Q. said...

It looks bad. As much as I'd like to believe he's clean, it's hard to do that.

12:42 PM  
Blogger Free Floyd said...

The title of my blog at this point is misleading but it was always a little facetious to begin with.

In all sincerity I am not attached to his winning. In other words, if he's busted, then let him be busted. I can easily believe he doped, just as easily as I can doubt it.

But what's substantive here is that I'm trying to elevate the level of serious discussion. I'm trying to make the science accessible to those who don't like to do their homework or who are just curious and suspect the media isn't telling the whole story.

The bottom line is that while it is likely that based on what little we know of Landis that he's busted. But we should also realize that there are things that are verifiable that just might have caused a false positive.

Ultimately what I'm seeking is not an easy answer. What I'm seeking is justice, not justice American style, not justice media style, but justice premised on the truth.

2:56 PM  
Blogger Amateur said...

Hi free floyd,

Interesting post. I think you are doing a great job elevating the level of serious discussion, and the media do a terrible job of covering these stories. Please keep going — and I think that your perspective would be useful in other doping cases, too.

However … according to the NYT article you linked to last week, the isotope ratio test doesn't just measure the ratio of C-13 to C-12 in the urinary testosterone; it measures that ratio in the testosterone and in another hormone:

"The test determines whether the testosterone in the athlete's urine has less carbon-13 than another naturally occuring hormone in the urine, like cholestorol. The test is considered positive when the carbon isotope ratio — the amount of carbon-13 compared to carbon-12 — is three or more units higher in the athlete's testosterone than it is in the comparison hormone. It is evidence that the testosterone in the urine was not made by the athlete's body."

This sounds like a very well-designed experiment, controlling for the influence of diet through the use of a reference hormone in the urine. The reference hormone and the athlete's natural testosterone presumably have the same source of carbon (i.e. food) unless some of the testosterone was made in a lab.

If Floyd is innocent there is some out-there physiology going on here. I think his goose is cooked.

7:10 PM  
Blogger mobytom said...

It seems unlikely from what I've read that diet could take the isotope test to a false positive, even if the test was only on testosterone. The first Features article linked on this page gives a good idea of the difference diet makes to the test - there are two or three distinct groupings based on diet, but the isotope test seems to measure beyond these.

I also read a study recently that says one isotope test is sufficient to give a true and reliable reading - if I find it again I'll post it here.

10:32 PM  
Blogger Free Floyd said...

simply put, no one knows how diet as a factor, in combination with time as a factor, affect the results of a IRMS. The only study, which wasn't really a study but rather a "short communication," supports my claim. the study indeed does not show that diet is sufficient for false positives, but that's simply because that study evaluates such a narrow profile: poorly defined diet measure, 1-3 month time span.

11:18 PM  
Blogger Pete said...

Great discussion. However, if Floyd's diet caused the elevated levels, wouldn't he have tested positive in the previous stage(s) where he wore the yellow jersey? It sounds like the dietary changes take months, not days, to maifest.

6:37 AM  
Blogger Free Floyd said...

Pete, the T/E test examines the ratio of T to E, not how much T you have. So no the T/E is not set up to test T levels per se and it would not have been detected previously. Whatever the source of the elevation of T or the depletion of E in his body, it went undetected until he drank a bounch of alcohol, which is well-understood to help just about anyone fail the T/E test. That got him in the headlights.

The dietary changes are linear, about 1% a month. That doesn't mean that the changes take a month to manifest, it just means that the unit of measure was a month. Perhaps it manifests itself as an increase of 1/30th of a percent every day.

7:07 AM  
Blogger Cerberus said...

Floyd, I hope you read this. ALL drugs have a biological half life in the human body. IF you took testosterone, the concentration will leave your body on a decaying exponential. Do you have ANY tests since the bad one? If so, you can plot those tests against time. If they don't follow the exponential (approximately a 2 week half life) then the vials were spiked. The excess testosterone was NEVER in your body.

Lets say you were tested after stage 19 or 20. If that test is normal, science PROVES that the lab screwed up and you're innocent.

I'm retired, but was a Chief Scientist at a National Lab. PLEASE, if you have other results since the bad one, EVEN NOW, they can be used to prove your innocence.

Hope you read this. contact info-

Virtually ANY Physicist, Biologist, or Chemical Engineer knows this information. Lawyers haven't a clue.

8:57 AM  
Blogger Kris said...

Being a scientist...I have an it possible for someone to spike his food or drink with testosterone. One can solubolize steroids (ie estrogen, testosterone etc) with ethanol or oils (like sesame oil). Who's to say someone didn't spike his salad dressing or food the night before the event.

9:04 AM  
Blogger Kris said...

As a scientist who has some experience working with hormones...I just wanted to point out that steroids can be solubolized in ethanol or oils such as sesame oil...who's to say that someone didn't spike his salad the night before or maybe even a drink along the route.

9:05 AM  
Blogger MLS said...

Wondered if you had any insight into what I've been hearing about the T/E ratio found in Floyd's test -- that his actual T was not so high as his E was extremely low, therefore influencing the ratio to be as high as it was (11 to 1, I think?) Any ideas as to how his E could have been so low, and whether that's either a red herring or another indicator of doping?

9:34 AM  
Blogger trust_but_verify said...

Hey Free,

There's a one line comment here pointing to another site that appears to me to be an attempt to commercially exloit the controversy. There's no substance, only ads for T shirts. You might want to moderate it away.


10:22 AM  
Blogger Erling said...

Well, now Landis has drawn back one of his excuses... the one where they drank beer and whiskey.

Hm... where does that leave us?

With 6 left - but an even more unreliable Floyd. Beeing caught in one lie / excuse doesn't really help in believing the next lies.

Sorry - I know you want to believe elsewise - but I say "Giulty as charged". Like Tyler Hamilton, Jan Ulrich, Lance Armstrong... and dozens other bikers.

11:35 AM  
Blogger Jason A. Miller said...

Floyd is coming out strong, it seems. Check his website for all of his scheduled media appearances and links to more statements.

From what I've read so far, he seems to be doing a better job. I do think his explanation for his list of "excuses" makes some sense, but that doesn't mean he's innocent. It will be interesting to see what he can do.

I wish there was a way for informed folks to see his results, bat around ideas and narrow down the possible causes for his positive. Some kind of wiki or forum for science and research experts to collaborate and discuss his numbers and his case. It sounds like some bright minds are reading this blog, but we have so little concrete information.

Floyd, if you read this and you really are innocent, maybe you'll consider some 21st century tech wizardry to tap into the collective wisdom rooting for you. Sure would be cheaper than three big shot lawyers. Just a thought.

12:04 PM  
Blogger CasualTourFan said...

Re: Monday 8/7/06--Floyd's appearances on TV

I hope someone on this blog will address the question of whether what Floyd did in stage 17 is plausible without him having used testosterone or anything else that is banned. As a casual fan of the Tour, I wonder if a lot of the hysteria in the media is due to the fact that Floyd's ride in stage 17 was so unexpected.

I'm reading on this blog that the science surrounding testosterone testing leaves some room to wonder, and I'd like to know what people think of the actual race day (stage 17). There's a fair amount of comment on the internet about how Floyd seemed angry that day. I don't know if that's just speculation, or whether there's any real evidence of him acting substantially different. People on other blogs have suggested that testosterone made him angry.

The way the whole situation has been handled seems so bizarre, unprofessional (Phonak, UCI), and irrational. Why would the Tour de France go through a charade of giving Floyd the yellow jersey, doing the ceremony in Paris, and then act so stupid? If they suspected he used something illegal before or during stage 17, why didn't they get the issue resolved before the peleton got to Paris?

I wonder about all the mumbo jumbo about the tests taking 2 days. Something seems extremely out of order about the way the Tour officials have handled this.

Also, with regard to the way Floyd's early statements came across in the media, I think he may have been somewhat naive about the world media. He hasn't been in the spotlight that much, apparently.

And from a basic human behavior perspective, if he was guilty, why would he be spending all this money on lawyers, going on network news shows, and generally wasting a lot of time and money. He isn't a rich man. This isn't Lance Armstrong with a PR staff and an unlimited bank account. Furthermore, USA Today now reports that Floyd's hip replacement surgery is scheduled in 2 weeks. I don't think he's doing today's publicity for fun.

I'm trying to imagine what I would do if I was a professional cyclist in a situation like this. If I had used a banned substance, and if I had been canned by my team, and if I had been pretty much "hung" by the world media, I think I'd just disappear, and say, "Oh well. Bad try."

If Floyd did use some form of synthetic testosterone before or during stage 17, or if he's been using "PEDs" right along (as many people apparently believe, based on entries in other blogs), wouldn't he know that he's history? It certainly doesn't appear that he's enjoying being on the news shows today. He looks and sounds stressed and certainly doesn't appear to be having a good time. Why bother with this if he's guilty?

This is a fascinating story. Thanks to "free floyd" for at least seriously considering some of the scientific aspects of this.

1:38 PM  
Blogger CasualTourFan said...

One more comment about Floyd's media appearances today: If he's lying about being innocent, he's not doing a real good job of it. He comes across as being what everyone says he is. A private person who isn't used to media exposure, and who isn't sophisticated in any way. I read somewhere that Floyd is the "anti-Lance". No PR staff, no entourage, no hype.

Maybe Floyd comes off as being stressed because he's still somewhat naive about the world, and maybe he really is innocent.

I'm not a conspiracy theorist, but there's a saying to this effect: "Just because you're not paranoid doesn't mean they're not out to get you".

If anyone in France is out to get Floyd in any way, they sure do look like turkeys while they're doing it.

1:56 PM  
Blogger Sue in Va said...

My family and I (2 PhD physicists) agree with what Cerberus said.

Also, I must add that we're LIBERAL Americans who have lived in France and know the bias of the french all too well. That's just one reason for our suspicion about the results of this test.

2:38 PM  
Blogger David said...

I'm intrigued by the possibility that the synthetic cortisone Landis took was converted by his body into a "natural" testosterone that would test "artificial" by the isotope test.

The liver partially recycles the steroid hormones through the enterohepatic circulation, so it is possible. Also, synthetic thyroid hormone can get in this circulation as well. By this theory, an isotope test performed on earlier samples would also be positive for "synthetic" testosterone. While this would not eliminate the possibility that Landis was cheating all along, it would refute the idea that he took a one-time injection before stage 17. Conversely, if only the stage 17 test showed altered isotopes, that would eliminate a pure natural variant, and leave only cheating and tampering as explanations.

3:44 PM  
Blogger arborjimb said...


Do you any idea where I can get a list of althetes that were false positive by WADA?

Bernard Legat comes to mind. He tested positive for epo and was skewered in the press. Then his b sample was negative but the damage was done.

Any other examples? Ho about althetes that have had their cases over-turned on appeal?

6:35 PM  
Blogger CasualTourFan said...

One more comment from a person who is basically just curious about all of this. I watched the 7 minute interview of Floyd and Amber that Good Morning America did (twice--on an unbelievably slow internet connection). They just look so totally "normal". They're ordinary people. Not celebrities. Not sophisticated athlete types. What if they're telling the truth?

They seemed calm, though somewhat stressed. Didn't appear to me to be lying. Floyd has such sad eyes, but I've looked at photos of him from long before the 2006 tour. His eyes are sad in almost all the photos I've seen.

What if Floyd is really innocent? Why is everyone so convinced he took testosterone? And why are people so vicious in their comments about him?

I think sports fans are generally jaded these days. I'm NOT a sports fan, and mostly by accident stumbled into watched the Tour. I'm willing to give Floyd the benefit of the doubt. The truth will come out sooner or later.

7:31 PM  
Blogger Free Floyd said...

Cerberus what an awesome idea. There must be some way to communicate that to him.

8:45 PM  
Blogger Free Floyd said...

MLS, apparently a lowered E level is concomitant with exogenous testosterone supplementation. so if is ratio is high because his E level is low, that doesn't indicate against taking T. I need to double-check that so don't hold me to it!

Erling, like I've said, I'm not attached to his winning. I am however attached, well into the fourth decade of my life, to the notions of truth and justice.

casualtourfan, there's no way to know for sure.l to know for sure, we'd need to recreate the conditions of that day and change factors. we don't have multiple copies of floyd landis or multiple copies of that day, so we have no avenue for knowing. but we caqn't get hung up on purifying the tribe. if he didn't ear that banana on his fourth birthday, would he have ever even ridden a bike? the way T is used, it's very difficult to demonstrate it as the proximal cause, the very difference maker between him and the other leaders. i'm still attached to my own theorry that his nearest competitors were suffering from greater muscular fatigue after 16 than Landis; Landis' metabolic crash on 16 left him, oddly enough, in better shape for 17, as metabolic fatigue is easier to recover from in 12 hours than muscular fatigue.

look, my cynic says that landis has millions of reasons (dinero + points of pride) to defend himself. those reasons are present regardless of his guilt or innocence.

it is unlikely from what I understand that IRMS was performed on earlier samples. again, another thing I need to double-check before I believe what I'm saying!

9:06 PM  
Blogger drehvial said...

Can anybody point out researchers or anti doping activists who back Landis in public (e.g. in a newspaper) and are not payed by himself or his former Phonak team?
So far I only found people who say that the tests are reliable and that they can hardly think of anything else than doping causing this results.

6:22 AM  
Blogger clint said...

"capitalize" would imply that i was actually making money from the site.
people like to support their heroes. I'm simply providing a way for people to do that. buy the shirt or not... i don't care, just show your support somehow.

6:52 AM  
Blogger dmacvid said...

Testosterone ??? Of all the doping he could have done
he chooses the easiest and most obvious thing they would test for? Somethings rotten in Denmark. I just remember they tried to do this to Lance Armstrong with a "bad" first sample.
I take testosterone replacement due to a pituitary issue and trust me, it took 3 weeks before I noticed the slightest difference. You don't take it and become superman in 48 hours. Something is going on here.

8:08 AM  
Blogger trust_but_verify said...

Yes, capitalize and exploit. There's nothing on the site to suggest support, only merchandising. The BBS has no entries but one asking "how do you feel?" which tries to have it both ways. The phrase itself is ambiguous and can be read either way, as an accusation or a defense.

I have nothing against T shirts or merchandising, but this is pretty shameless. Defending it here and still having the site contents be as vacuous as they are is telling.

9:11 AM  
Blogger Free Floyd said...

This site is not a place to debate the relative merits of merchandising. Thanks.

5:48 PM  
Blogger CasualTourFan said...

I listened to a few minutes of an interview with Floyd on BBC that was done today (BBC Radio website). He doesn't come right out and say that he thinks someone contaminated his urine sample, but he suggests it could have happened.

Floyd said he really wonders what happens to the samples before they get to the lab, as well as while they're in the French lab. He says he knows the urine samples aren't anonymous when they're in the lab. Maybe he's just pointing out all the possibilities for someone to mess with samples, but maybe he knows something?

What do you think is the likelihood that Floyd has been talking to Lance and discussing the goof-ups of the French lab in the past? It wouldn't surprise me if the lab is part of a messed up system.

So now, in addition to maintaining his innocence and repeating that he never took any banned substance, Floyd is suggesting that someone (the UCI, WADA, Tour officials, other people?) have some sort of agenda against him.

If he's innocent, one can certainly understand how angry and frustrated he must feel.

6:20 PM  
Blogger bigtelcobike said...

Assuming the following assertions are correct:
1. T only influences performance if taken over long periods.
2. T is tested for on numerous occasions. Results of other tests were negative.
3. Elevated levels of T are what improves performance, but elevated levels were not detected.
3. T does not instantly speed recovery--so it does not explain Stage 17.

Then how could Floyd's performance have been "enhanced"?

Oh, and by the way, if Floyd were tossed out, the race really doesn't mean anything. Oscar P. wasn't the 2nd best rider in the race. tactically Phonak let him pick up 30 minutes, because they were in the lead and didn't think Oscar was a threat in the mountains or the TT. Absent Floyd, even the self-imploding T-Mobile team might have gotten itself together and put Kloden at the top of the podium.

6:28 PM  
Blogger trust_but_verify said...

If Floyd was doping, it wasn't short term. That's a straw man, easily knocked down. It would make more sense for there to have been a long term steroid program to build up sprinter twitch muscles for matching attacks up hills. This would increase the T, masked by synthetic E. What would make more sense is that stages 16/17 disrupted the masking, leading to lower E, a blown ratio, and synthetic showing up in IRMS. However, IRMS of samples before and after 17 should also show exogenous because of the half-lives involved.

Until we see IRMS results of samples on either side of stage 17, its hard to get a sensible picture. If there is no exogenous in the adjacent samples, that suggests that there is an anomaly with the stage 17 result. If the adjacent tests show exogenous, then that would indicate a long term doping program.

The problem is that there may not be any IRMS on the adjacent samples, and the samples may have been destroyed after being negative on the T/E screen.

9:22 PM  
Blogger Rads said...

Would they have been destroyed? Lance's B samples from 1999 where there were no Asmales still existed seven years later.

11:53 PM  
Blogger drehvial said...

Concerning the possibility of tampering with the samples: Both samples are sealed in presence of the athlete, the seal of the B-Sample is broken in presence of the athlete or a representative (in Landis's case one of the two spanish lawyers - so either Luis Sanz or José Maria Buxeda - attended the breaking of this seal) the B-Sample is then examined again in presence of the athlete or one representative (Deuwin de Boer for Landis). But of course the MI-6, CIA, Mossad and the RG are playing their own game...

12:35 AM  
Blogger b2cool said...

I hope that Floyd and his lawyers have seen this article:

It seems that there is some evidence that his drinking binge the night before the 17th stage could have caused a spike in his testosterone levels, according to a study done at the Scripps Research Institute.

6:57 AM  
Blogger Free Floyd said...

The CIA has no incentive whatsoever to make Landis' results positive. I can see how various spooky shadowy elements of our government participated in a conspiracy to shock and awe Americans into WWIII by blowing up the WTC in order to shake them down for trillions of war-appropriated dollars. I can and do believe that, but the evidence and the historical prcedents and familial linkages are there to support such a supposedly wacko idea. But sabotaging Floyd Landis' success? Maybe the French intelligence service would have many an incentive for messing with Landis, but certainly not the CIA. Jeez louise let's maintain some degree of credibility in our critiques of secrecy in government.

8:42 PM  
Blogger Free Floyd said...

We've thoroughly covered the relationship between alcohol and the T/E ratio test. Alcohol is indeed a significant false positive source for the T/E ration test. Alcohol ingestion would not have made Landis positive for the IRMS test, however, and he did test positive on that test. So alcohol is at best a remote influence on why he's positive.

8:59 PM  
Blogger drehvial said...

Please be aware of irony

Thanks ;-)

12:50 AM  

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