Peas Lettuce Help You

Which common vegetables should be limited by hyperglycemic or diabetic people based on Brix measurements and the presence of starch?

Avril Eich

Aeris Kwon

Mr. Johnson and Mr. Mathot

Sierra Vista Middle School, IUSD

Abstract

Many have been taught that vegetables are healthy. However, people must remain cautious of which vegetables should be included in their diet. This holds especially true for diabetic and hyperglycemic people since many vegetables contain unwanted glucose and carbohydrates, negatively impacting these individuals the most. If they knew which vegetables contained high sugars, they could limit them accordingly within their diet. People with diabetes or high blood sugar could benefit if they viewed the conclusion of this project.

Nine common vegetables underwent two experiments to determine which should be limited for diabetics and people with abnormally high blood glucose. The first required a Brix refractometer, a telescope-like tool, to calculate and measure the Brix, the percentage of dissolved sugar content in a liquid. To measure the Brix of each vegetable, its juice was extracted by crushing it with a metal spoon or ice cream scooper; the liquid was then transferred using a dropper to the Brix refractometer. The refractometer was held toward a light source, and the Brix measurement was seen through the eyepiece and then recorded. This process was repeated for all nine vegetables, and the dropper and refractometer were cleaned between each test to avoid cross-contamination. The second test used iodine to detect the presence of starch within the vegetable. The vegetable was classified as starchy if the iodine turned from its natural color, brown, to black a few seconds after coming into contact with it. If the vegetable is non-starchy, the iodine would remain brown, and this test was repeated on all vegetables.

Both tests had reasonable results that matched the hypothesis. Peas and sweet white corn should be the most strictly managed since both are starchy and have a high Brix, with peas at 9-10 degrees Brix and sweet white corn at 8. However, russet potatoes, yellow onions, carrots, and garlic should also be eaten in moderation since all have a Brix of at least 8 degrees or a large amount of starch. Romaine lettuce, green beans, and plum ruso tomatoes do not have to have strict limits since they all have little to no starch and a low Brix measurement.

This project would positively contribute to people with diabetes or hyperglycemia by helping them create a healthy and balanced diet that suits them. It would raise their awareness of which vegetables negatively impact their health and how to manage them.

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Which vegetables should be limited

by diabetic or hyperglycemic people based on Brix measurements and the presence of starch?

Problem

Introduction

A model comparison between normal and high blood glucose

Source: National Institute of Diabetes and

Digestive and Kidney Diseases

A diagram that shows how different types of carbohydrates affect the body (modified)

Source: Big Dog Pet Foods

A comparison of blood glucose responses between pre-diabetics, diabetics,

and non-diabetics

Source: SNAQ - Blog

Introduction Cont.

Plants produce carbohydrates and oxygen in a process that occurs within their chloroplasts – known as photosynthesis – using sunlight, carbon dioxide, and water. When humans digest plants, their bodies break down the carbohydrates into glucose to provide energy for their brain and blood cells. However, due to genetics, diet, and personal circumstances, some people build up excess glucose in the bloodstream, resulting in hyperglycemia, also called high blood sugar.

Hyperglycemia causes diabetes mellitus, or simply diabetes, a disease that occurs when the pancreas produces little to no insulin needed to absorb glucose in the bloodstream. Diabetes can increase the risks of hearing loss, poor blood flow, joint problems, teeth or gum infections, and eye, kidney, nerve, and heart damage. It affects the amount of insulin people’s body releases, a hormone that helps cells absorb glucose. Prediabetic people have abnormally high blood sugar levels that are not high enough to be officially diagnosed as diabetes.

A Brix measurement is the percentage of dissolved solids, or sugar content, in a liquid. These dissolved sugars include soluble fiber, which can decrease the risk of heart disease and cholesterol levels and help manage blood sugar, the National Institutes of Health states. Although dieticians may recommend some vegetables with high Brix due to their high fiber content, consumption of these vegetables should still be monitored since the other dissolved sugars, such as glucose, fructose, and galactose, can be harmful. In this project, peas, sweet white corn, yellow onions, carrots, and garlic should have high Brix measurements due to high amounts of soluble sugars and fiber. One degree Brix represents one gram of sucrose, or table sugar made of glucose and fructose, dissolved in 100 grams of solution. It essentially indicates the sugar concentration as a percentage by mass. When digested, starch breaks down into glucose, which is absorbed into the bloodstream and causes blood sugar levels to rise. Starchy vegetables, therefore, raise blood sugar levels faster than non-starchy types. Of the vegetables we will test, peas, sweet white corn, and russet potatoes are starchy vegetables. Meanwhile, yellow onions, garlic, green beans, carrots, plum ruso tomatoes, and romaine lettuce are not starchy. However, carrots and green beans contain starch in a very minuscule amount. Therefore, as stated by the American Diabetes Association, both are considered non-starchy.

Hypothesis

Based on our initial research, peas, sweet white corn, russet potatoes, green beans, and carrots will have starch. However, carrots and green beans will contain very low amounts of starch. Meanwhile, sweet white corn, peas, carrots, yellow onions, and garlic will have the highest Brix measurements because they contain a lot of dissolved sugars. Therefore, peas and sweet white corn should be limited the most for diabetic and hyperglycemic people because of their high Brix and starch content.

Materials

Ingredients:

• 1 russet potato
• 1 plum ruso tomato
• 1 yellow onion
• 1 romaine lettuce
• 1 canned cut green bean (no additional salt)
• 1 organic garlic
• 1 organic carrot
• Sweet white corn
• Peas

Equipment:

• 1 Brix refractometer
• 3 droppers
• 30 mL Iodine
• 1 metal spoon/ice cream scooper
• Paper towels
• 50 mL water (in beaker)
• 1 strainer
• 10 petri dishes

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Procedure

Using water for calibration and a sample test

1. Open daylight plate and place 2-3 drops of water onto prism using dropper. Close daylight plate so that the water spreads across the entire surface of the prism without air bubbles or dry spots. Allow the sample to test on the prism for approximately 30 seconds before going to next step.
2. Hold Brix refractometer in the direction of a bright light source and look into eyepiece. You will see a circular field with graduations down the center. The upper portion of the field should be blue, while the lower portion is white.
3. If needed, turn the calibration screw until the boundary between the upper blue field and lower white field meet exactly on the zero scale.

End of calibration, Calculating Brix measurements

• Open daylight plate and delicately wipe off water with paper towel. Use spoon or ice cream scooper to squeeze juice out of vegetable in a petri dish. If needed, use strainer to squeeze out juice easier.
• Place 2-3 drops of vegetable juice onto prism using dropper. Close daylight plate so the vegetable juice spreads across the entire surface of the prism without air bubbles or dry spots. Allow the sample to test on the prism for approximately 30 seconds before going to next step.
• Hold Brix refractometer in the direction of a bright light source and look into eyepiece. Take the reading where the boundary line of blue and white cross the graduated scale. The scale will provide a direct reading of the concentration.
• Record the Brix measurement of the vegetable.
• Open daylight plate and delicately wipe off water with paper towel.
• Repeat for all vegetables.

Testing for presence of starch

• Wash out dropper with water. Place 2-4 drops of iodine onto the vegetable using dropper.
• Observe if the color of iodine changes to black.
• Record observations.
• Repeat for all vegetables.

Procedure Cont.

A closed Brix refractometer

An open Brix refractometer

Brix refractometer diagram

Source: Integrity Soils

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Results

Results Cont.

Lettuce

Water

(for calibration)

Carrot

Garlic

Water on daylight plate

(for calibration)

Onion

Discussion

The nine various vegetables underwent two tests, one for the presence of starch and the other to determine the Brix measurement. Starch was detected in the peas, sweet white corn, green beans, russet potatoes, and carrots. However, carrots and green beans are still classified as non-starchy because, referencing our research, they contain very small quantities of starch. Peas, sweet corn, yellow onions, carrots, and garlic had the highest Brix measurements, all at least eight degrees in Brix. According to our initial research, russet potatoes, green beans, romaine lettuce, and plum ruso tomatoes should have lower Brix measurements since they don’t contain a lot of soluble carbohydrates such as glucose, fructose, and galactose. This proved correct in the data as all the vegetables were in the lower range, measuring six or below. There were no connections between starch and Brix measurements since garlic and yellow onions have a high Brix but are non-starchy, while russet potatoes are the opposite.

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Conclusion

The project’s objective was to identify which common vegetables should be limited by hyperglycemic or diabetic people based on Brix measurement and the presence of starch. The experiments used russet potatoes, yellow onions, sweet white corn, peas, carrots, romaine lettuce, green beans, plum ruso tomatoes, and garlic to conduct our experiments. It was confirmed with the data that peas, russet potatoes, sweet white corn, yellow onions, and garlic should be limited for people with high blood sugar or diabetes due to their abundance of starch or high Brix. However, restrictions on peas and sweet white corn should be emphasized since they have the most dissolved sugar content and starch presence. It was concluded that carrots, plum ruso tomatoes, romaine lettuce, and green beans do not have to be strictly managed since they have little to no starch and a low Brix measurement. Overall, the outcome determined that the experiment was successful and achieved the initial intent. Our hypothesis was proven to be correct by the results of the experiments as well.

Reflection/Application

Reflection:

• An improvement that could be made is to find a more consistent and easy way to extract the juice from the numerous vegetables since crushing the vegetables took lots of effort and time.
• We learned that vegetables can be harmful or beneficial in different situations based on the various types and amounts of carbohydrates.
• We tested only nine of some of the most popular vegetables. The next step would be to conduct more trials to gather more evidence.

Application:

If a person with diabetes or high blood glucose does not know how to handle their diet, we can help them decide which vegetables to eat and limit. Through our research and experiments, we understand how to define which vegetables diabetics and hyperglycemic people should restrict. However, we still acknowledge that some vegetables do not have to be entirely excluded from their diets if they are eaten in moderation and cooked healthily.

References Cited

Mayo Clinic, Diabetes diet: Create your healthy-eating plan (June 11, 2024)

https://www.mayoclinic.org/diseases-conditions/diabetes/in-depth/diabetes-diet/art-20044295

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Medline Plus, Carbohydrates (March 25, 2024)

https://medlineplus.gov/carbohydrates.html

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Mayo Clinic, Diabetes - Symptoms and Causes (March 27, 2024)

https://www.mayoclinic.org/diseases-conditions/diabetes/symptoms-causes/syc-20371444

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National Institute of Diabetes and Digestive and Kidney Disease (NIDDK) - What Is Diabetes? (April 2023)

https://www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes

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JamJarMMX, Iodine Test for Starch (April 10, 2012)

https://www.youtube.com/watch?v=HO_q8GPl3bE

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United Concordia Dental, Common Healthy Foods High in Sugar (January 2024)

https://www.unitedconcordia.com/business-services/employers/blog/common-healthy-foods-high-sugar

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South First, Crafting the perfect diabetic diet chart for Indians: See what doctors recommend (July 3, 2024)

https://thesouthfirst.com/health/what-is-an-ideal-diet-for-a-diabetic-patient-see-doctor-recommended-food-chart/

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CDC, Fiber: The Carb That Helps You Manage Diabetes (May 15, 2024)

https://www.cdc.gov/diabetes/healthy-eating/fiber-helps-diabetes.html

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Career Power, Glucose C6H12O6- Chemical Formula, Structure, Composition, Properties, Uses (September 18, 2023)

https://www.careerpower.in/school/biology/glucose

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WebMD, Danger of Uncontrolled Blood Sugar (June 3, 2024)

https://www.webmd.com/diabetes/uncontrolled-blood-sugar-risks

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UCLA Health, Diet rich in veggies can decrease risk of Type 2 diabetes (April 26, 2023)

https://www.uclahealth.org/news/article/diet-rich-veggies-can-decrease-risk-type-2-diabetes

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WebMD, Starchy vs. Non-Starchy Vegetables (March 18, 2024)

https://www.webmd.com/diet/difference-between-starchy-non-starchy-vegetables

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Healthline, What’s the Difference Between Starchy and Non-Starchy Vegetables (October 16, 2024)

https://www.webmd.com/diet/difference-between-starchy-non-starchy-vegetables

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Mettler Toledo, Brix Measurement (No date shown)

https://www.mt.com/us/en/home/perm-lp/product-organizations/ana/brix-meters.html#:~:text=Brix%20is%20a%20measure%20of,in%20100%20grams%20of%20solution

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References Cited Cont.

American Diabetes Association, Non-Starchy Vegetables for Blood Glucose Control (No date shown)

https://diabetes.org/food-nutrition/reading-food-labels/non-starchy-vegetables

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National Institutes of Health, Health benefits of dietary fibers vary (May 24, 2022)

https://www.nih.gov/news-events/nih-research-matters/health-benefits-dietary-fibers-vary#:~:text=Soluble%20fibers%20mix%20with%20water,%2C%20legumes%2C%20and%20various%20vegetables

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American Diabetes Association, Understanding Carbs (No date shown)

https://diabetes.org/food-nutrition/understanding-carbs

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Integrity Soils, How to Use a Refractometer (No date shown)

https://integritysoils.com/blogs/resources-lists/how-to-use-a-refractometer

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Big Dog Pet Foods, Hidden Sugars in Commercial Pet Foods (November 22, 2024)

https://www.bigdogpetfoods.com/guides/hidden-sugars-in-commercial-pet-foods-by-narelle-cooke

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SNAQ, Normal Blood Glucose Levels: For People With & Without Diabetes (October 15, 2021)

https://www.snaq.ai/blog/normal-glucose-levels

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