Why is Health Advice Conflicting? – By Dr. Alan Christianson:
Hi there. Dr. Alan Christianson here. I want to give a very thorough answer to a very simple question that I was asked. It was a very good question but to answer it thoroughly it requires a little bit of a back story. The question was. How come some thyroid experts give different opinions on iodine? Some say that you should get lots of it and some say you should avoid it. Why is that and what is right? Have you ever heard that thing about how if you give someone a fish they are set for a meal but if you teach them how to fish they are set for life. I am going to teach you how to fish. I am going to give you some input on this.
Evidence comes from a variety sources and not all are created equally. So think about this. If a trusted advisor, perhaps your accountant came to you and said. You know here is the number you should put on your form for the IRS. Okay that is one level of evidence. Okay lets say the kid next door penciled in or used their crayon and wrote some numbers on a piece of paper. Which one would you trust more for your tax returns? Both gave answers to the same question perhaps but both should not be treated equally. This is true in all areas of science.
We have different claims that approach us and we have to have different ways to sort them out. We have to gain evidence and evaluate them in some ways. You know if some one came to me and said that Elvis Presley was still alive and well and living on the dark side of the moon I would be skeptical. I would doubt that claim. There is evidence that he did pass away. He would be quit a bit older and we would not expect people to be living on the dark side of the moon so i would be skeptical. That would be a claim that would require a large amount of evidence. Now if that same person took me on a journey and i got to see the whole trip. We went to the moon and we got to meet the king and maybe he sang some songs I would reconsider. So that is the difference between having a belief and having an idea.
Beliefs we base on facts such as our feelings or our connections where as ideas or concepts we form based upon evidence and they can change. If you take me for that ride and show me the king and he sings some songs I might believe that Elvis is alive on the dark side of the moon but short of that i will be skeptical. So the evidence we get there is this whole system of hierarchy. There is a formal way we can compare evidence. You know kind of like the rock paper scissors game where this one beats that one. Even in more detail you can think about it like poker where you got a Royal Flush that always wins. Then you have got two of kind and four of kind some where in there, i am not a gambler. The same thing is true for evidence.
So if you have two claims of evidence that are different claims the easiest thing you can do is say okay, what do you have in your hand. What is the level of evidence. I am going to give you guys a really easy system by which you can think about this. So imagine you want to lay down and rest and you are outdoors and you want something secure and steady that you can trust. You can lay on a hammock, or on a pile of pine needles or you can lie on a cot. A cot would be a nice thing. It would be secure and steady and it would not be moving or blowing and it would be comfortable enough. So we are going to rest are beliefs on a COT also.
The top of this is C and then O and then T at the very bottom. Now I want to make it clear that all levels of evidence are useful and they all have there place and they all should be honored. When there are levels of evidence that are different and somebody has a high level of evidence and that claim is going against a lower level of evidence then we would put more stock in the higher level of evidence. We would trust our accountant over the neighborhood kid with the crayon.
So to the bottom of the COT we have T and T is for Thoughts or Theories or ideas. We could also say hypothesis or things that we think. In medical school I remember learning about biochemistry and I remember seeing that you could make a giant map out of most the chemical reactions that occur in the body and it could be like the size of a wall almost. What happens is that you could go from one point to any other point is you took enough steps. I would hear people say perhaps this nutrient, this herb, this substance could do something to this pathway because it eventually connects. At first I thought this was really intriguing and I though it was amazing that you could work out so many things by just looking at this map and thinking about it. Then pretty soon I realized you could make anything you wanted to because there is so many connections. It really is like a giant map of America. You could go from one point to another point not necessarily by a logical route but everything always connects. That is kind of the pitfall about thoughts and ideas is that we could imagine almost any scenario.
We could think about how I remember there was this story about a movie in which in the future that people decided that all the opposite of the things we thought were healthy were healthy. We could imagine all these scenarios. So if we are just operating at the level of a thought or idea the we have there is a lot of room for possible error and we call these mind experiments. Hopefully there is some foresight. There is some extra checks and training that go into the ideas but even with that there can be a lot of pitfalls. So when someone has a theory or an assumption that’s really the lowest level of data and it is good to be aware of it for what it is. Say oh wow, okay so that is what you think, cool. Is that an idea or is there some information behind that. It is good to get that clear and out in the open. If it is an idea so be it. A lot of wonderful findings did come from ideas so we do not want to discredit the initial thoughts but we want to know them for what they are and see them for what they are.
The greater experience the person who comes up with the thought has and the greater expertise they have the more relevant it is but only to a point. No matter how great the expert is, their thoughts are all thoughts and any evidence to the contrary does trump the thoughts and does become more meaningful then just thoughts or ideas. So next up on this tier we have O and I think about that as observations or things you can see. Things you measure. There are many different levels to observations.
You can look at things after they happened. We would call this a retrospective study. You can look back after the fact. Maybe you have got a group of a thousand people and say a certain number of people die from lung cancer. You could look and see how many were smokers and from that you could make some correlations. That would be a retrospective study. You are looking backwards in time and this is the lowest level of observational data.
So next up we would have a cohort study. It is the exact same thing but we are looking ahead. So in that scenario we could take a group ten thousand people, some of which we know to be smokers and we could track them moving forward and see how many would develop lung cancer and other diseases. They would be a cohort study and it is just looking forward in time.
Now the fewer variables you are looking at the more powerful your study is. If you have got a whole lot of things you are checking. A whole lot of different numbers, well the odds are something will change whether is was caused by any predictive thing or not. So the fewer number of things you look at the more powerful and then of course the larger number of participants the more powerful. So yeah retrospective and cohort studies.
Next up we have interventional trials and that is where you actively do something. Where you would have say a group of people and you would have them take Folic acid and see what what there cancer risk was for the coming years. That would be an interventional trial. Also the same things apply. The more people involved the more meaningful it is. The more years involved the more meaningful it is. We also have to think about how this data can be generalized.
If we are looking at how people who have arthritis are responding to one specific medication it may be hard to draw implications that are relevant to the population at large about that. It may be only relevant to that population. Again here the numbers are really important. You know so much data that people talk about in blogs or in other sources is based upon there own personal experience and that is relevant. That is a case study and if they make some change to their lifestyle and they see change in their health that would be an interventional study. It would be a number 1, one person study and that is not a large number but it is useful data. It should be seen for what it is and its limitations but it is useful data. So yeah, so much of data that gets put out and debated against is really more so just thoughts or what we call opinions or it is interventional studies of one. Like here is how i think it will work or here are the things that happened to me. Those are not things I would discredit or ignore but they are not the strongest or most compelling evidence.
So after interventional studies then we have what is called randomized controlled trials. Those are cases to where people are put into different groups and one group has the intervention and one group does not. So I mentioned about Folic acid for example. If you had people half given Folic acid and half given a placebo and then you watched there rate of cancer that would be a randomized controlled trial and that would be useful data.
Now the top, the very top of this COT would be C. this would be Conclusions. So this is what happens when people who are reviewing research and they analyze studies. The very pinnacle of this is what we call a meta analysis and that is where many different randomized studies are pooled together and looked at as a unit. The cool thing is that this gives you more meaning then any one study by itself. There is a lot ways in which one study may have biases or may have an unusual group that was involved in it and the outcome may not be typical. So the top of the conclusion thing would be meta analysis or experts reviewing other groups of studies and making position papers on that. So the very top we got Conclusion, then we have Observations then we got Thoughts or Theories.
They are good ways we can learn about the world around us. They are all useful but it should be known that there is a hierarchy and that observations are always more powerful then theories and that conclusions are always more powerful then observations. So the next time someone makes a claim about something such as how much iodine you should take or what diet is best. First thing is you should have a little switch go off that says okay what level of evidence is this coming on. Is this coming from a conclusion from many studies that have been looked at together? Well done studies. Is this observational data from trials that might be cohort studies looking into the future, retrospective studies looking into the past or interventional trials? Or was this more of a thought or an idea or an opinion? They are all important but just know where it is at. We will talk a lot more about evaluating evidence and looking at claims and also some of the biases we have built into our brains. Fascinating stuff but there is a good reason we have formal ways to evaluate information because our brains do not do that very well automatically.
So thank you so very much for participating, as if there was a formal classroom. Yeah I enjoyed the time explaining this to you all and again I want you all to be able to fish. Do not just listen to me as an expert and say okay that is it, the end of it. If there are valid concerns I want to educate you on how you can sort out claims yourself and what is going to the move the needle the most for your health and what is not. Take good care and we will talk soon.