Science Buddies: "Ask an Expert"

Hi Vish,

Individual variation is the very reason that we need multiple test subjects. It's also why each person will serve as his/her own control, since it would not make sense to compare one person's test food to another person's control. The reported GI for each type of food is likely an average from many different people.

Keep in mind that other factors will affect the GI. As I mentioned, each person needs to be fasted for at least 12 hours and not consume anything before the test. Things like hormone levels (especially of insulin and glucagon) can affect each person's reaction, as well as what the person ate the day before each test. These are variables you cannot control, so you can talk about them in the discussion of your results.

It will be interesting to see if there is at least a consistent trend for GI with the different test foods. Please keep me posted as you collect more data! Once you have the data, I would be happy to help you figure out the best way to present everything.

Best,
Heather

Hi Heather,

Thanks for the feedback. I will share the info and be happy to get your advice on how to represent the data.

Regards
Vish

Hi Heather,

I wanted to share one thing that I noticed in one of the volunteers blood glucose. It constantly shows a decrease after eating food and only after 2 hours he shows an increase. Also I am trying to measure just the area under the curve starting from baseline( fasting food value) and the value at end of 2 hours. Sometimes I notice the volunteers blood glucose does not come back to the fasting level within 2 hours. So I just the area by extending the curve to the baseline.

Also I am plotting each person data for different food in a single graph for my lab work, using different color for each food. And then plan to calculate the GI using the individual person AUC for different food/ AUC of Bread multiplied by 100.

Once I done calculating the GI of different food for each person, I would put that in another graph to see the variations for same food among the different volunteers.

Will keep you posted.

Regards
Vish

Hi Vish,

Thank you for the update! Everything sounds great. It is very interesting that one of your volunteers has an initial dip in blood glucose. I wonder if he or she has a very high insulin response.

It sounds like you are doing the right thing to calculate the area under the curve when the blood glucose has not reached baseline by 2 hours. Just extend the graph straight down, rather than assuming a continuation of the curve.

Looking forward to more updates!

Heather

Hi Heather,

Thanks

I do have a question on plotting the graph. The measure of blood glucose meter is in mg/dl where as I see most of the AUC using mmol/l. DO I need to re-plot the graph after converting to mmol/l.

For now the values for the AUC reading looks like this

1.4740 mg/dl . min
2.2590 mg/dl.min



Regards
Vish

Hi Vish,

Since the glycemic index is calculated as a percentage of the reference AUC, the most important thing is that your test AUC and reference AUC are in the same units as each other. Since you measured everything with the same glucose meter, that will work for you. So the short answer is no, you do not need to re-plot your graphs.

If you want your results to be comparable to other studies, you could convert mg/dl to mmol/l. To convert from mg of glucose to to mmol, you will use the molecular mass (g/mol) of glucose (by adding the masses of its component elements from the periodic table). To convert from deciliters of solution to liters of solution, note that there are 10 deciliters in a liter.

Since both of these conversions would be the same for every measurement you did - since glucose does not change its molecular mass, and there are always 10 deciliters in a liter - doing the conversion would not change the shape of your graph. You could keep your graphs and just report the converted values for reference in a separate table.

Heather

Thanks Heather.

I will keep the graph as it is. I am wondering if I got to take 2 more trials for the same food or 1 test for each food with 4 volunteer is good?

Regards

Vish

Hi Vish,

Since you are measuring GI for four people on multiple foods, I think your experimental design is good. Doing multiple trials on the same individuals could help you account for variation within individuals, but I'm not sure that's the most important thing here. Honestly, I think finding more volunteers would help more than adding trials for the same volunteers. So you can stick with what you have, or see whether you can convince anyone else to participate in your study.

Keep me posted!

Heather

Thanks Heather.

I will try to see if I can find new volunteer. Will keep you posted. Also as I am doing the test I am also making a draft of the content I am planning to use on my board. If you want to review let me know what is the best way to share it.

Regards

Vish

Hi Vish,

Sounds great! If you are able to put the materials for your board into pdf or jpeg format, you can upload it as an attachement (or multiple attachments, depending on the size) right here on this forum. I would be happy to review them for you.

Heather

Thanks Heather. I am working on this and will have most of it done by this weekend.

Meanwhile this was some of the title for the project that me and my partner discussed with our volunteers. let me know what should be the best or suggest us one.

1. Prevent Diabetes. Does the type of carb matter?

2. Does the type of carbohydrate really matter!?

3. What type of carbohydrate harm us the most?

4. How can we prevent diabetic by selecting different carbohydrate.?

5. Should every one know there own Glycemic index for different carbohydrate?

Hi Vish,

I'm glad things are coming together!

It's important to make sure your title reflects what you actually studied. You are not looking at a way to prevent diabetes, but rather what carbohydrates might be better for a diabetic to consume when trying to control his or her blood sugar. I would also avoid implying that carbohydrates harm us, as they are essential macromolecules needed for nutrition!

How about something like the following:
1. Are there "good" carbs? The effects of different carbohydrate foods on glycemic index.
2. How do different carbohydrate foods affect blood sugar?

I hope this helps!

Heather

Hi Heather,

Thanks for your suggestion. I will discuss this with my partner.

Also when you get a chance pls see the pdf and let us know if it looks ok.

We would like to mention you as our mentor. Please send what info we can add to the project as we wanted to give credit to you for your help.

Regards

Vish

Hi Vish,

Your presentation looks great! I do think you should include the graph to show how you calculated the AUC, since that is easier to explain with a figure.

Overall, you did a very thorough job and you should be very proud.

I am happy to help, and you do not need to give me credit. My name is Heather Liwanag, and you can just say that I am an Expert for Science Buddies.

I hope your presentation goes well!

Heather

Thank you Heather. I will keep you posted on how our presentation goes. Let me know if you have any other suggestions.

Vish

Hi Heather,

I am glad to let you know that my project won second place at the Regional Science Fair. I have been asked to participate at the state level. I will let you know how it goes.

Thanks again for your help.

Regards
Vish

Hi Vish,

Thank you for that exciting update! You developed a unique and well-conducted study, and it's so great that you earned second place. Make sure to incorporate any feedback from your judges at the regional fair as you prepare for the state fair. Let me know if you need help with that process.

Best,
Heather

Thanks Heather,

I came first in the Medical and Health Science section in the Arizona State Fair (Azsef)

Thanks once again for your help.

Regards
Vish

Hi Vish,

That is such great news! Congratulations on a job well done.

Heather

Thanks Heather.

Also for next year one of my topic of interest was Pancreatic cancer. I thought it will be a nice start if I understand what it is and start reading about it so I can then think about some project ideas.

I see you have been mentoring on this subject as well. Let me know if you have any resource I should look up.

Regards

Vish

Instead of Rice one of the many foods my daughter is testing is Whole Wheat Pasta vs White Pasts.
Is there a rule of thumb as to how much pasta and how much water to combine before mashing ? Or Blender?
Thank you

Also planning on testing fruits, veg, and juices.

Hi Vish,

bumblebee27 wrote:Also for next year one of my topic of interest was Pancreatic cancer. I thought it will be a nice start if I understand what it is and start reading about it so I can then think about some project ideas.

I see you have been mentoring on this subject as well. Let me know if you have any resource I should look up.

I love how you think ahead! I am a physiologist, but I do not have particular expertise in the topic of pancreatic cancer. The student I was mentoring did the Science Buddies project called The Cancer Genome Anatomy Project: https://www.sciencebuddies.org/science- ... p011.shtml. There are a lot of resources available in the information provided for that project.

PubMed (http://www.ncbi.nlm.nih.gov/pubmed/) is a wonderful resource for anything related to molecular biology. You can find everything from scientific articles to gene sequences.

I hope this helps you get started, and I would be happy to continue helping you along the way!

Best,
Heather

Hello Hun,

Welcome to Science Buddies!

Hun wrote:Instead of Rice one of the many foods my daughter is testing is Whole Wheat Pasta vs White Pasts.
Is there a rule of thumb as to how much pasta and how much water to combine before mashing ? Or Blender?
Thank you

Also planning on testing fruits, veg, and juices.

Were you planning on doing the Science Buddies project "How Sweet It Is" (https://www.sciencebuddies.org/science- ... p049.shtml) with these foods? Or did you want to test glycemic index? If you scroll through the earlier posts in this thread, you will see that testing glycemic index requires blood draws from human volunteers, whereas testing the glucose content of food is a simpler procedure.

The important thing when comparing foods is to pick a standard amount for comparison. With solid foods that you plan to mash or blend, you could start with the same wet mass (weight of the food with water in it, including cooked pasta). For the juices, you can compare the same volume.

I hope this helps you get started. Please post again if you have more questions.

Heather

Hi Heather,

Happy New Year!

For this year's science project we started on doing a project on Ultrasonic sensors , but we are running short in time and think we might not be able to complete it. Then we thought of extending the GI project. We have 2 ideas

1. See the effect of genetically modified foods and compare GI. We are not sure if we can get food that are labelled genetically modified in the .
Looking to use Rice, pasta etc similar to the foods we did last year.

2. The other option is to find the effect of GI on the same foods we did last time, but pair it with a constant amount of protein. Thinking about Fish.

We are more leaning to the second option. We would like to see what your suggestion is.

Regards
Vish

Hi Heather,

I know this is an old topic and wanted to get your attention.

Earlier I posted that I am extending this project this . We today decided to modify what we want to try.

We would like to pickup one of the carbohydrate we tested earlier and combine that with different proteins

so thinking about
Carb+fish
Carb+chicken
Carb+lentils

Wanted to see if you have any suggestions

Regards
Vish

Hi Vish,

So sorry for the delayed response. I was away at a conference and have been playing catch-up since I returned.

I think your idea for combining one of your carbohydrates with a protein is a really great idea!

bumblebee27 wrote:so thinking about
Carb+fish
Carb+chicken
Carb+lentils

Remember to include a control, by measuring the same carbohydrate alone.

Otherwise, I think this is a great plan. Any reason you are avoiding red meat here? I like the use of chicken, fish, and lentils (for a vegetarian/vegan option), but I think it would also be interesting to look at red meat. Of course, I only suggest this if it is not a problem to add another trial for your subjects. If 4 trials (control, fish, chicken, lentils) is as much as you are willing to inflict on your subjects, I think it's a well-rounded design and you will be good to go.

By the way, I wanted to address your other idea regarding the genetically modified foods. Honestly, I do not see any reason that genetically modified carbs should affect GI any differently than non-modified carbs. (The exception would be if they were specifically modified to exhibit a lower GI.) Most genetically modified foods are modified for pest resistance and/or flavor, which are genes that would not necessarily affect the GI. Basically, I think you picked the better project idea from the two you listed. (Again, sorry for taking so long to get back to you.)

Please keep me posted as you continue with this project! I really enjoyed helping you with the original project, and I am looking forward to seeing what happens with this one.

Best,
Heather

Hi Heather,
Thanks for the suggestion. We are going to use red meat as another protein and have a control. I will inform you on what we will be doing.

Do you have recommendation on how much protein we should add for each meal.

from,
Vish

Hi Heather,

We started the experiment this weekend. When we researched we found the suggested quantity is 2:1 ( Carb : Protein) Ratio. So we are calculating 25gm of protein in the given food to add to the 50 gm of carb ( we are doing potatoes since it had the high GI).

Regards
Vish

Hi Vish,

Sorry I missed your question about how much protein to add. I'm glad you found a suggested ratio! (I probably would have said that it is most important that you keep it constant and note the ratio.)

Please let me know how it goes!

Heather

Hi Heather,

Thanks for your reply. We did experiment today using red meat and found each volunteer's blood sugar did better when they also eat protein.

I will keep you posted.

From,
Vish