We get exposed to fitness facts and dietary advice every now and then. Apparently, on a daily basis if I am not wrong. Just so you know, the relationship between nutrition choice and the impact of non identical choices on health cannot always be inferred spot on without uncertainty. What do I mean? I mean if you've read somewhere that you need to have 8 glasses of water every day no mater what, I would say that's not the case for everyone. Let's find out what do researchers and nutrition scientists base their conclusive opinions on and no I 'm not talking about the tests conducted on lab rats.
To establish or better say perceive association between dietary intake and health consequences, a researcher may chose from an assorted range of study patterns. Whatever be the approach, it can basically be either an experimental or an observational study. Let's dive a little deep in the ocean of details to understand things.
What is an Experimental Study?
In an experimental way of studying the relationship between nutrition and health, an actual experiment is performed not necessarily in a closed laboratory but it could be done anywhere and most importantly with any number of test subjects. Suppose, we want to study the impact of olive oil on cholesterol levels in humans. An experimental approach to study this would recommend bringing together a large number of people with somewhat similar health condition i.e. high levels of bad cholesterol and then segregating them into two groups, one of which could be referred to as the main group of study and the other one the control group. The main group would be served with olive oil in certain prescribed amounts and ways while the control group remains untreated in all ways. After a span of time both the groups get diagnosed for their cholesterol levels and an opinion is laid based on the experimental analysis. If the main group shows considerably significant fall in bad cholesterol levels as compared to the control group, it could be stated that olive oil worked wonders for cholesterol control. You see, the role of control group is inevitable when performing an experimental study.
This approach, however needs big investment as the test subject has to be large enough and the participants need to be followed over a long course of time.
What is an Observational Study?
In contrast to the experimental methodology, an observational way of studying the relationship between nutrition and health considers not intervening the regular dietary habits of the participants. Considering the same example, researchers who choose to go by the observational strategy would bring together a group of people who already have olive oil in their regular diet as the main group and a control group would constitute people who don't use olive oil at all. Imagine that they find lower cholesterol levels across the group of people who used to consume olive oil. Let me ask you, how fair would it be to declare that the consumption of olive oil is responsible for low cholesterol levels in general? I say, not fair at all if we go by this particular observational study. Why? you'd ask. There is a possibility that those who consumed olive oil belonged to a section of society that was already health conscious. Maybe they used to exercise or possibly had a planned and controlled diet whereas the control group that showed high cholesterol levels might have had a bad eating pattern. Who knows? Unlike studies that employ experimental setups, observational studies cannot actually determine the exact effect of any dietary element on health.
Observational studies can be categorized into following sub-types :-
- Ecological Study
- The participants or test subjects under ecological study are not individuals but a share of the entire population of an area or even a country for that matter. You'd have heard positive interrelationship between the Mediterranean diet and heart health. How do you think the idea that Mediterranean diet was good for heart got formulated? The might have been an ecological study of the masses living in the Mediterranean that would have come up with such promising results. This study cannot be extrapolated to individuals. For example- If Europe has less number of crimes per year as compared to Asia and alongside the alcohol consumption in Europe is also found comparatively lower , this could lead to an assumption that alcohol consumption is directly related to the crimes. Though the example I took is pretty obvious but we can't extend this opinion to very individual level. Possibly, Europe has a better crime management system. This is just an example.
- Cross Sectional Study
- A cross sectional observational study makes an observation of the dietary intake or lifestyle habit and its impact on health at the same time. Suppose, I am doing a cross sectional study on the relationship between running and weight loss. I would meet a few test subjects and examine them through questionnaires maybe. Imagine I find out a lot many people who consider running daily no matter what and I also get to interview people who would seldom indulge into physical activities. Now what do you expect? Which group should have a better BMI? Those who run daily. Pretty obvious? but imagine I found just the opposite, those who used to run daily were heavier on the scale than those who were physically almost inactive. To explain, because we are looking at running and weight aspect at the same time, we also interviewed many people who took up running just because they were over weight and while the were still in process we made our observation. So here, running was not the cause of heavy weight but heavy weight was the cause of running. This is a severe drawback of this approach.
- Case Control Study
- This method of observational study makes an assessment of dietary habits of two groups, one which is called the main group and the other that is referred to as the control group. Same, as we discussed earlier. Both the groups are evaluated and examined on their dietary or lifestyle habits and the difference in noted down. This difference is then analyzed to make approximations on the health and nutrition relationship. Suppose, we were to find out the relationship between industrial smoke and lung cancer. We chose the main group to be the people who live nearby the industries or the industrial workers and the control group to be the town dwellers or the rich class people. Don't get amazed when I tell you what we found. Imagine, the rich town dwellers had more number of lung cancer patients. We would straightaway say that industrial pollution doesn't cause lung cancer. That would be wrong. Why? Maybe the town dwellers indulged into something more dangerous that we left out of the scene. Possibly, they were prone to smoking and drinking. What do we learn? These studies can be deluding if not done carefully.
- Prospective or Cohort Study
- This is considered to be the most effective of all the observational studies we saw earlier. Participants prerecord their dietary and lifestyle habits mostly by registering themselves on online research portals (these days) and keep submitting track records every now and then. This process takes over decades of tracking the test groups to conclude something from the observation. Since the dietary habits are recorded long time ahead of the occurrence of any health complication, unlike cross sectional studies there's no confusion between the cause and the result. However, like other observational studies the biggest limitation is the unfair and fabricated data submission by the test subjects.
Whosoever be your fitness mentor or guide, the tips they share, the suggestions they make or the so called diet secrets they reveal are based on one or more than one of the above mentioned research methodologies. So, the next time you hear that soy consumption causes decline in testosterone levels, make sure you find out what kind of study was done to come up with such a conclusion. Though a lot of studies and findings have stood the test of time, out there lay many ideologies based on delusional researches. The idea is to stay aware when going through any advice specially related to health and stuff. Why? because it's not only misleading studies but also marketing ploys that have come into play with some false facts and suggestions of course for their self interests.
-Inspired by
WageningenX
No comments:
Post a Comment