Nutttt

Name: Sara Ashmore

Course: NFS 2220

Date: 02/26/2020

Lab 1: Digestion

Introduction

The main purpose of food is to provide energy and nutrients to the body. When we ingest

food, our body will begin the process of digestion by breaking down these foods into smaller,

absorbable particles: Carbohydrates are broken down into glucose, fats into fatty acids and

proteins into amino acids. These particles are then absorbed into the blood stream.

Foods can be categorized according to the glycemic index. The glycemic index is a

measurement based on how quickly blood glucose levels rise after eating a particular food. The

body’s preferred energy source is carbohydrates (glucose).

When carbohydrates are consumed, they are broken down into glucose. When glucose

enters the blood stream, blood glucose levels rise, which causes the body to release insulin to

induce glucose uptake by its cells. Insulin is a hormone produced by beta-cells in the pancreas.

Fasting blood glucose levels range from 70 mg/dl to 100 mg/dl. An individual is

considered to be hypoglycemic if fasting blood glucose levels are below 70 mg/dl. If fasting

blood glucose levels are above 125 mg/dl, an individual is considered to be diabetic. If an

individual’s blood glucose levels are between 100 mg/dl and 125 mg/dl, the individual is

considered to be pre-diabetic.

Objective

The purpose of the laboratory session was to observe volunteer’s digestion by measuring

the effect of various foods on blood glucose levels.

Materials and Methods

In order to perform this lab, nine volunteers fasted for at least 8 hours before the

laboratory procedure. Blood glucose levels were measured with a blood glucose meter and test

strips. Measurements were taking after an 8 hour fast and then at 15 mins, 30 mins and 45 mins

respectively after each volunteer consumed one of the following foods: Pepsi as example for

simple carbohydrates, wheat bread as an example for complex carbohydrates, a protein shake as

an example for high protein foods, cheese as an example for high fat foods, and Diet Pepsi as

control measure for the experiment.

Results

The results are shown in the following table and graph:

Student Blood Glucose(mg/dl) Food

Fasting 15 mins 30 mins 45 mins

1 98 109 109 103

2 92 100 86 95Simple Carbohydrate: Pepsi

Average 95 104.5 97.5 99 3 89 96 82 94 4 82 98 88 102

Complex Carbohydrate: Wheat Bread

Average 85.5 97 85 98 5 118 111 127 107 6 103 95 93 94Protein: Protein Shake

Average 110.5 103 110 100.5 7 92 95 91 88 8 74 71 78 84Fat: Cheese

Average 83 83 84.5 86 9 80 82 69

10 84 96 79 70Control: Diet Pepsi Average 82 89 74 70

On average, blood glucose levels rose by almost 10 mg/dl between fasting and the

15 mins mark in volunteers drinking a can of Pepsi (simple carbohydrate). Blood glucose levels

then gradually decreased, but remained elevated at the 45 mins measurement.

In volunteers consuming a slice of wheat bread (complex carbohydrate), blood glucose

levels first rose by 11 mg/dl between the initial measurement and the 15 mins measurement, then

dropped to 85 mg/dl at the 30 mins mark and then rose again to 98 mg/dl at the 45 mins mark.

Blood glucose levels of volunteers drinking the protein shake (high protein food) varied

as well. On average, blood glucose levels were relatively high at fasting, but then decreased at

the 15 min measurement, increased at the 30 mins measurement and decreased again at the 45

mins measurement.

In the high fat group, blood glucose level remained fairly stable at around 84 mg/dl.

In the control group, there was slight variation in blood glucose levels between each

measurements. First blood glucose levels increased slightly, but then decreased gradually.

Discussion

The glycemic index is a measurement based on how a particular food effects blood

glucose levels. The higher a food ranks on the glycemic index, the higher blood glucose levels

will rise after consuming this particular food. Things like candy bars, pop and white bread are

ranked high in the glycemic index as they are made up of simple sugars, which elevates blood

glucose levels significantly. In terms of our experiment, the individuals drinking Pepsi represent

this group. Our prognosis was that blood glucose levels should have been the highest in this

group at the 15 mins mark. In total numbers, average blood glucose levels were in fact the

highest at 104 mg/dl in this group at the 15 minute measurement. Blood glucose levels then

gradually decreased at both the 30 mins measurement and the 45 mins measurements, which is

considered normal as blood glucose decreases due to insulin release and eventual glucose uptake

by cells.

Blood glucose levels of the volunteers consuming wheat bread (complex carbohydrates)

were also increased at the 15 mins mark, which indicates that glucose entered the blood stream.

However, due to the fiber contained in wheat bread, blood glucose levels then showed a

decreased at the 30 mins mark and then an increase again at the 45 mins measurement. This is

considered normal as the fiber in wheat bread decreases rate of absorption and glucose therefore

entered the blood more slowly. This is why individuals suffering from diabetes are advised to eat

foods high in fiber to keep blood sugar levels stable.

The individuals consuming protein shakes, both had elevated blood glucose levels at the

initial measurement, which indicates that both individuals may be pre-diabetic or they may have

consumed food the morning of the laboratory assignment. After consuming the protein shake,

average blood glucose levels decreased. In general, protein does not affect blood glucose, neither

in a lowering or increasing way, which is why I am assuming that both volunteers probably

weren’t fasted at the point of the initial measurement.

Blood sugar levels in the individuals consuming cheese remained fairly stable, which is

what we predicted since fat does not affect blood glucose.

Blood glucose level in the control group (Diet Pepsi) gradually decreased, which is

considered normal as both volunteers did not ingest any macronutrients over the time period of

the measurements.

Reference

Wayne State University. (n. d.). NFS 2220: Human Nutrition Laboratory.