Science Buddies: "Ask an Expert"

Are we really what we eat? And how is that possible?

This is an excellent idea for a project, and can help illustrate why conventional dietary wisdom is important, or on the other hand completely wrong. Thats the great think about science, as soon as we think we got it, we’re back to square one.

So are we what we eat? I think your best option for this is to divide whatever type of dietary intake you plan on looking at into basic groups. Carbohydrates, fats, proteins, etc. And then determining what path these go on when they are ingested. After that it is possibly to break down a specific meal by nutrient type and say where it goes. For instance a cheese burger contains carbohydrate, protein, and these go to a specific part of the body, or are used in certain metabolic processes.

To a certain extent, yes we are what we eat, but only in regards to certain nutrient groups. You will also discover some of the things that we thought we used directly (like protein or fat for instance) is not used in the same form in which we consumed it. Also the source of cholesterol and other lipids in the body may not come from where you would expect them to.

To further answer your question you may want to research the quite unattractive area of what is left of our food after we are done with it. By figuring out what is excreted as waste, you can determine what isn’t present and then figure out what happens to those substances.

Look forward to hearing more about your research. Please feel free to write back if you have any more questions.

Mark

Here's a little something I wanted to add to Mark's insightful reply!

Here's the way I think about "you are what you eat": All the different nutrients, minerals and vitamins that I consume with every meal have a direct impact on the way my body functions and looks. For example, a diet rich in protein enables muscle growth and repair. So you can think of the muscles in your arm as being built by proteins your body obtained from your meals. It isn't meant to be taken literally - eating an orange will give you lots of Vitamin C and fiber that will benefit your body, but the orange does not become a part of your body in its original form.

All the cells in our body require many different nutrients to survive and function. What we eat is broken down and used to grow new cells, maintain existing ones, and enable them to work efficiently so that our bodies can function at their best. At that core level, we are all made up of what we eat!

Hope that clarifies things a little. Tell us more about your project!
Tanvi.

Thank you Mark and Tanvi . It means a lot for you two to help me understand a little bit more about my project and what I have to research.

Can I use earthworms for my project that involves metabolism? And would I be able to have them in a specific diet ?

No problem, let us know if you need anything else.

There is a movie on Netflix, it is a cheesy documentary about nutrition and goes on to talk about the food industry, which is not related to your project at all. If you disregard that however he does a great job of explaining how carbohydrates and fats are utilized. The movie is called Fat Head. If you can watch it in your spare time it could be useful, if not it is information you will most likely find elsewhere anyway.

Thank you . I will try to find time to watch that documentary. I have another question. Can I use earthworms for my experiment? And can I have them in a specific diet?

That would entirely depend on what you are attempting to investigate. Do you have an early experiment design or specific question you are trying to answer? Maybe even a working hypothesis or observation you would like to narrow down on?

One idea for using earthworms, off the top of my head:

Prepare granular food for the worms in fixed proportions of carbohydrates, fats and proteins, with varying levels of these nutrients. Feed them to different batches of earthworms, with as many earthworms per batch as you can handle (~20-30 is a good number for statistical analysis). You can keep earthworms fed on their regular diet as a control. Then, after a fixed time (maybe a few weeks) you can grind up the earthworms and measure their protein, fat and carbohydrate content. This will give you an idea about how the earthworms utilize nutrients they obtain from their diet. You can also analyze their feces to see what components of the food their bodies did not use.

Of course you'll have to do some background reading about the worms' diet and how their digestive system works. Also plan your experiment in a way that allows for good statistical analysis - have a sufficient number of samples, and try to make sure there aren't any other factors affecting your experiment that you cannot control. Read about how to analyze protein, carbohydrate and fat content and try this analysis on a small number of worms first to make sure you learn the techniques well!

Think about this some more, and feel free to share your own ideas so we can help you develop them into experiments!

Thank you , I have a couple more questions. How does genetics come into obesity ? Also why does obesity happen? How does metabolism work?

Metabolism and the metabolic process is extremely complex, but not impossible to get a handle on. The best place to get a rough overview of the process is probably a biology textbook, probably college level. Then once you know what to look for you can do better research online. Most published papers on the topic will assume that you already have an understanding of the topic already. There are some excellent videos about the mechanism done by Khan Academy as well.

Obesity is simply an excess of "fuel" being consumed. If it is not used, it gets stored somewhere. Ages age this mechanism is what allowed early humans to survive long periods without food. Now though, we have about all the food we can ever want, so that has a totally different effect on us. Is there a genetic link? Maybe, but it is important to understand how little a genetic pre-disposition may matter. A person may have a certain gene that affects their metabolism in a way to lead to obesity earlier in life, or with less calories being consumed. But just because the gene is there doesn't mean they will be obese, or are obese and there is nothing they can do about it. It just means that becoming obese will be a little bit easier for them than the rest of the population.

Is the amount of carbohydrates you consume depending on your body mass index ?

The body mass index is a rough measure of obesity calculated with your height and mass. I'm not sure exactly what you mean by your question. Certainly, people who are larger (with a higher BMI) will generally need to eat a larger number of calories to maintain that weight, although there are a number of other factors including that person's normal metabolism (basal metabolic rate) and their activity level (an athlete will need to eat significantly more calories due to their intensive training than a person who is sitting at a computer most of the day). Furthermore, eating more carbohydrates may lead to a higher BMI, just as eating too many of any type of calories will contribute to increased weight and a higher BMI.

I hope this answers your question.

Thank you , you did answer my question.

I understand that obesity is due to lack of diet and lack of exercise which causes the metabolism to not be active. The thyroid actually plays in important part in metabolism. The thyroid gland is made of two types of cells which need iodine to produce those hormones but does the lack of iodine effect obesity?

Hi!

While I am not very familiar with your topic, I do think that the effect of iodine on the actions of the thyroid gland would be an excellent area to research. If you're interested in pursuing this, I found this link which may help you with preliminary research. Try scholar.google.com too!
http://www.lef.org/magazine/mag2011/oct ... ncy_01.htm

Hope this helps.

Hello,
I wanted to know how can I test for the lack of iodine in human metabolism using E coli cells. I want to use E coli cells because I cannot use human cells for my experiment. Is there a possible way I can use E coli? Does anyone have any feedback or ideas regarding other bacteria that may be a better test specimen?

Thank you.

Hi Gaby,

It is good that you are looking for alternatives to using human cells. That is why we have model organisms!

When it comes to model organisms for human cells, I recommend that you look into culturing yeast instead of bacteria. Yeast are eukaryotes, which means their cells have a true nucleus, just like human cells. (Yeast are actually unicellular fungi.) Yeast are also capable of performing aerobic respiration, which is a crucial part of cellular metabolism in humans.

I recommend researching yeast culturing, and posting back here when you have more questions.

Best,
Heather

gaby__08 wrote:Hello,
I wanted to know how can I test for the lack of iodine in human metabolism using E coli cells. I want to use E coli cells because I cannot use human cells for my experiment. Is there a possible way I can use E coli? Does anyone have any feedback or ideas regarding other bacteria that may be a better test specimen?

Thank you.

You could use Yeast to study metabolism as Heather mentioned. I do not know however if you can specifically answer your iodine question, as iodine is actually a anti-microbial to an extent.

Hello,
I wanted to know if i can use any type of yeast for my experiment ?

Hi Gaby,

You can use baker's yeast, which is fairly easy to grow and not dangerous. See these projects for details:
https://www.sciencebuddies.org/science- ... p009.shtml
http://www.disknet.com/indiana_biolab/b021.htm

I have also seen the species Saccharomyces cerevisiae grown for lab experiments. Check out Carolina Biological Supply for cultures.

Heather