Science Fair 2009

By: Katie Lewis

Big Question

• If a food or liquid is high in glucose, does it make your blood sugar higher than foods with lower glucose?

Hypothesis

• If a food of liquid is high in glucose, then it is not necessarily worse for diabetics (that is, it will not necessarily make their blood sugar higher) than foods or liquids with lower glucose concentrations.

Materials

• Variety of Juices and Foods– Juices: Water (negative control), Carrot, Orange,

Apple, Cranberry, Lemon, Lime– Foods/Liquids: Peanut butter, vinegar, milk,

tomato• Glucose test strips• Small test containers• Stopwatch• Paper for recording results

Written Procedures

1. Pour a small amount of each liquid being tested in a container.2. Get ready to start the stopwatch.3. Dip the test strip in the liquid.4. Start the stopwatch as the test strip has been dipped.5. Wait for the amount of time specified on the test strip directions

(30 seconds).6. Compare the color on the test strip with the color on the side of

the container to determine it’s glucose concentration.7. Write down the amount of glucose concentration for sample.8. Repeat steps 1-7, of this section for all foods and juices.

More Written Procedures

9. Make a data table of results.10. Graph results.11. Research the glycemic index of the foods tested and

graph alongside the glucose concentration of each food.

Interesting Facts

• There are many common foods that have not been tested for a glycemic index rating (such as lemon and lime juice).

• I was surprised that peanut butter has a very low glycemic index.

• When diabetics have taken too much insulin, they should eat a food with a higher GI to quickly raise their blood sugar (so they don’t go into insulin shock).

• Eating low GI foods helps to prevent insulin resistance and also helps weight control.

• Glucose is the only fuel used by brain cells.

Observations

• Foods high in acids typically have lower GI ratings.

• Foods high in fiber (such as some vegetables) and whole wheat foods have low GI ratings.

• Carrot juice and orange juice have the same glucose concentration but carrot juice has a much lower GI rating.

• Cranberry juice has the highest GI.

Control

• My control in this experiment was water. It has a glucose concentration of 0; therefore it should register 0 on the glucose test trips, which it did.

Data

Analysis of Data

• The objective of this experiment is to investigate the concentration of glucose in common juices and foods.

• I also researched the glycemic index of these foods which is a rating that indicates how quickly a food raises blood glucose levels.

• Keeping blood glucose from going too high is important for people with a disease called diabetes.

• My research showed that the glucose found in a food doesn’t always indicate how it’s going to affect blood glucose levels.

• There are many components in foods that determine how they will affect blood glucose levels (such as fiber, and other elements).

Conclusion

My hypothesis was correct, because certain foods such as peanut butter are high in glucose, but their low GI rating doesn’t result in higher blood glucose levels. Next time I would add other foods such as vegetables because it would be interesting to find out their glucose levels in relation to their GI rating. I suspect many vegetables have a low GI rating. One of my questions I would like to research further is what components of low GI foods make them so healthy for you.

References • How Sweet It is! Measuring Glucose in Your Food:• http://www.sciencebuddies.org/science-fair-projects/project_ideas

/FoodSci_p049.shtml• Blood Glucose Levels:• http://www.netdoctor.co.uk/health_advice/facts/diabetesbloodsug

ar.htm• Foods Highest in Glucose:• http://www.nutritiondata.com/foods-000010000000000000000-1.h

tml• The Glycemic Index:• http://www.mendosa.com/gi.htm• Glycemic Values of Common American Foods:• http://www.mendosa.com/common_foods.htm• Food and Diet in Diabetes:• http://www.diabetesnet.com/diabetes_food_diet/glycemic_index.p

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