Science Buddies: "Ask an Expert"

Hello Science Buddies:
I am revising my post because I am thinking of other things and realized my first request was too broad. I want to use planaria to test the affects of toxic food additives and see if there's a connection between memory and toxic additives. I'm not sure which one to focus on but I have heard that sugar substitutes may have an affect on memory and trigger the Alzheimer's disease. I am also considering testing preservatives and maybe food dyes (red, green) to observe the effects of memory. I will show that aspartame, for example, affects a planaria's memory. To do this I would teach my planaria to follow a path. Then I would regenerate them and introduce new ones to a food additive. And then I will see if the new ones remember the path. Please tell me what you think? I'm working with my mom and doing this at home for a science fair project. If you have other suggestions, please let me know. Thank you so much.

Hi Ruby_Roo123,
Your experiment looks so interesting! We would be happy to offer some advice. Planaria have actually been used to examine the preservation of memory through DNA. This means that multiple experiments have used Planaria to understand why Planaria offspring actually remember what their parents remember, because these memories may have been encoded in the DNA the mother gave to its offspring. This is why I would suggest using an entirely new set of Planeria rather than regenerating the ones that you will train. This should help make sure the new Planaria do not remember the path from the old Planeria which might help your data make more sense by reducing the number of other factors affecting your Planeria. Also, I read a really interesting research paper that used a simple method to train Planeria, much simpler than having the Planeria follow a path. Data suggests that Planeria tend to actually familiarize and somewhat memorize their environments. This is why I suggest training the Planeria to become familiar with finding food in a distinct environment. You could measure the amount of time it takes the Planeria to reach their food before the additives, then you can have them consume the additives and place them in the same environment. The Planeria should be timed again...the faster they reach their food, the better their memory of the environment might be and visa versa. This method is actually quite well-known; however, the research paper I have linked will give you some useful suggestions to reduce bias when using it. Don't forget to place your Planeria in the dark while their not being trained or tested! Here's the really helpful research paper! https://mechanism.ucsd.edu/teaching/f13 ... a_2013.pdf If the research paper is too long for you, I've created a list of the most relevant parts to your project. However, I do suggest reading the entire paper because I may have missed some useful information. I would read....
The Abstract, the introduction (starting line 134), and the materials and methods section. Your experiment has definitely intrigued me! Please tell me how your results turn out and good luck!

Thank you for the help and suggestions! I will let you know!

You're welcome!

Hello Science Buddies,
For my work with planaria, could you tell me how to find the LD50 dosage information for food toxins that I want to test? I know that for many animals there are amounts established for the lethal dose. I want to look at red dye #40, aspartame, sodium nitrate and BHA/BHT. Do you know if this is available anywhere? Do you have any suggestions? Thank yoU!

Hi Ruby,

I have to make one comment first about your choice of terminology. When you say something is toxic, most people assume that you mean toxic to humans. The 'additives' that you are thinking about, artificial sweeteners, food colors, preservatives, etc are not considered to be toxic to humans at the concentrations used in food. If they were toxic the FDA would not have approved their use in our food. Aspartame, for example, has been studied extensively and no health concerns have been found:

http://www.cancer.org/cancer/cancercaus ... /aspartame
http://www.eurekalert.org/pub_releases/ ... 121113.php

I know there are some claims on the web that aspartame is an 'excitotoxin' that can affect brain function but I did a PuMed search and there is no good published evidence for this. Experiments that have been done using very high doses of aspartame, 2000-4000 mg/kg, are so much higher than what any human would taken in through food and drink that toxicity claims based on those cannot be related to humans:

J D Fernstrom, Aspartame effects on the brain, European Journal of Clinical Nutrition (2009) 63, 698–699; doi:10.1038/ejcn.2008.5; published online 30 January 2008


Scientists are very careful how they say things especially when their words seem to express a bias or foregone conclusion. You should likewise be careful in stating the hypothesis of your project. You will use planaria as a test subject so your hypothesis should be something like: Artificial sweeteners (aspartame), food colors, nitrates and preservatives (BHA, BHT) inhibit the memory (or reproduction, or ability to regenerate, or whatever effect you choose to look at) of planaria. That is what you will prove or disprove in the experiments.

As to what concentration of these substances to use, here's a link to a project to test aspartame on memory and mortality in planaria: https://apps2.societyforscience.org/abs ... &Year=2007 but I could not find where they mentioned the aspartame dose.

I did a search for planaria and nitrates and found that planaria need nitrate to grow so I think that one is definitely nontoxic unless you used a very high concentration.

I found no information about effects of BHA or BHT on planaria.

Using planaria as test subjects for memory or regeneration experiments makes a really great science project! Just be careful in the statements you make until you have proof to back them up.

Sybee