The Placebo Effect.

[matt21]

I have read a lot into the placebo effect and see it to be a very interesting subject, so just wondered what other people thought of the subject?

For those who aren't familiar, the placebo effect is when a positive outcome arises simply because the subject believes that something beneficial is being ingested.

An interesting study by Beedie et al., (2006), had trained cyclists complete 3 10km trials, under placebo, 4.5 and 9mg.kg.bw. Although the subjects were decieved and given a placebo (cornflour) for each trial. RESULTS: 1.3% & 3.1% more power when 4.5mg & 9mg of caffeine was believed to be ingested respectively. All subjects reported caffeine-related symptoms.

This raises an interesting question; are the benefits of caffeine psychological, physiological, or a mixture of the two?

And also does this sort of study put into question the physiological benefits of other ergogenic aids, creatine, glutamine, etc...

[NU_nutrition_TS]

This is why any gold-standard scientific intervention study should be double-blind placebo-controlled - see here:
Double-blind, Placebo-controlled Study

This is supposed to compensate for placebo effects because neither the subjects, nor the researchers conducting the study, know who is getting the drug and who is getting the placebo. Once the study is complete and all the data is gathered, a third party 'reveals' who got what and the data can be interpreted so that any placebo-effect is filtered out.

Are you also aware of the less well-known nocebo effect? This is the theory that believing something will have negative effects will often result in those negative effects being manifested - even if the supposed causative agent is actually inert (like a placebo)!

[matt21]

I am aware of the guidelines, and also the nocebo effect! I think I've worded it a bit badly maybe!!

The idea that I am trying to put forward is maybe better worded like this;
I have completed a number of trials for maximuscle, high5, and also for a number of students, and simply I know the effects of caffeine so can tell/have a good idea when I am on the ergogenic aid, placebo (despite researchers trying to mask the effects through exercise, etc). I know the consistency, taste, etc of carbohydrate drinks which imo simply cannot be replicated so the gains that these researchers are getting from these "ergogenic aids" could they be down to the placebo effect and individuals linking the increased mental alertness, etc of caffeine to increased performance.

I know the need for post experimental questionnaires should eliminate/reduce this, but how honest are the answers given, etc.



(Carb drinks is probably a bad example as they are obviously accepted as an ergogenic aid, although the gains maybe exaggerated through the placebo effect.)

[NU_nutrition_TS]

Well this has always been my concern with placebo-controlled trials. Is the placebo truly inert? Is it sufficiently like the the agent being tested in appearance, smell, taste, texture, etc. so that no-one really knows which they are getting? Everyone has heard the 'well-known fact' that placebos are just 'sugar pills' - and in the study you quoted, they used cornflour (a refined carbohydrate) - how 'inert' are these, really?

[matt21]

Good point, I've never thought about the effects of cornflour on the body, although I suppose it was stable across all of the trials in the study I mentioned. Although it does have a valid point, as to if a placebo trial is actually on an inert substance!

Just out of interest do you believe substances like caffeine have as profound effect as documented in studies, or is it more likely that the placebo effect contributes?

I'm quite dubious about the effects of a lot of substances and I just find it a very interesting subject that's all! Don't know if anyone else shares this opinion!!

[NU_nutrition_TS]

I try to avoid caffeine for no other reason than withdrawal from it seems to spark migraines in me!

I have never taken a caffeine supplement so I only used to get it from beverages like coffee and, to be honest, I never noticed any effect from ingesting caffeinated beverages! Maybe I wasn't taking a high enough dose or maybe I am a non-responder or maybe the effects were too slight to notice. Maybe I didn't believe it would have any effect so, a la the nocebo effect, that is what I experienced (or didn't!).

Then again - if withdrawal from caffeine caused migraines - I have to deduce that somewhere along the line it does have a real metabolic effect. Or was it because I believed withdrawal from caffeine would give me a migraine so, when I did stop, I experienced one?

^I think I am getting a headache!

This is another pet peeve of mine - that there is any way to separate subjective from objective!

[matt21]

hahaha!! It is a complicated subject, which rather annoyingly doesn't have a definitive answer, although I suppose it's nice that it is open to debate!

I on the other hand do ingest caffeine before aerobic exercise, and I do feel that it has a profound effect on my performance. Although obviously it could be due to me simply believing that caffeine does have a positive effect on performance.

I suppose it might be interesting to see if simply the smell of coffee (associated with caffeine) in a lab would have an effect on aerobic performance in comparison to control? and maybe not informing that athlete of the purpose of testing, although this it could be difficult to mask/ignore a steaming pot of coffee in a lab?!

[NU_nutrition_TS]

Not entirely related but it reminds me of a Penn & Teller show on organic produce. They interviewed the typical hippy-drippy, fruitarian types - as well as more run-of-the-mill organic aficionados - about why they chose to eat organic produce. Aside from the usual supposed health benefits (more nutrients and less pesticide/herbicide residue), all said that the taste was much better than conventionally grown produce.

One of their researchers went out on the street in a local street market setting and set out a stall from which they canvassed shoppers about their love of organic produce and then challenged them to several taste-test sessions.

One of the tests involved a non-organic banana, which was cut in half. One half was served on a blue plate and the other half was served on a red plate. People were told that the half banana on the blue plate was organic while the half banana on the red plate was conventionally grown. Most taking the test admitted to preferring/buying organic bananas because they tasted better. When they tasted the banana from the red plate they said it didn't taste of banana - rather bland, with a funny after-taste. But when they took a bite of the banana from the blue plate, they became enraptured, saying it really tasted of banana, with a full, sweet taste and a nicer texture. Then the bomb was dropped - they had tasted both halves of the same non-organic banana. Their preconceptions - plus the misdirection about the half on the blue plate being organic - led them to believe they could actually taste a difference!

[Wotan]

I too have thought long and hard about the placebo effect. In my case it was to test the efficacy or otherwise of various electrical devices which were supposed to alkanise and acidify water. I also in the past wanted to test ionisers and magnetic field generators etc.

The only way I found I could test them to my satisfaction was to use batches of bean seed. Two seed trays, twenty seeds per tray from a batch of forty la la la. Whatever else you can say beans do not have much of a communicable subjective experience and so they only way to measure the benefits was with a ruler at two day intervals. Empirical evidence - well as near as I could get!

[NU_nutrition_TS]

You remind me of Tom and Barbara in The Good Life, conducting their 'talking to plants' experiments! I hope you didn't name one of your beans Douglas? Ha ha!

The way I see it, it's not so much the study subjects having a subjective experience but the experimenter!