Carbohydrates & Type 2 Diabetes
Ashleigh King
HUN 3230 DL
Dr. Labyak
October 18, 2013
Carbohydrates & Type 2 Diabetes
–What is a carbohydrate?
The foods that humans consume can be broken down into three main categories:
proteins, fats and carbohydrates.
These categories are referred to as
macronutrients and are the basis for the fuels that our bodies use to function
properly. Carbohydrate or, “hydrated carbon”1, is the body’s preferred energy
source and is especially important for our nerve cells. “The major source of energy
fuel in the average human diet is carbohydrate, supplying half or more of the total
caloric intake.”2 As the name carbohydrate implies, it is made up of carbon,
hydrogen and oxygen.1 We get carbohydrates primarily from plant sources in our
diet such as vegetables, fruits and grains. Through a process called photosynthesis,
plants make the most common and simplest form of carbohydrate called glucose.1
-Digestion, Absorption & Function
Carbohydrates exist as two main classes: simple carbohydrates and complex
carbohydrates.
disaccharides.
The simple carbohydrates are the monosaccharides and
The complex carbohydrates are the oligosaccharides and the
polysaccharides. Glucose, being the most abundant monosaccharide in the body,
usually attaches itself to other monosaccharides, forming disaccharides and
complex carbohydrates. As a carbohydrate enters digestion, it’s main goal is to
break down polysaccharides and disaccharides into monosaccharides that will
eventually be converted to glucose.1 Digestion begins in the mouth, stimulated by
chewing and aided by saliva. Salivary amylase breaks down the carbohydrates into
polysaccharides and maltose. Salivary amylase is then destroyed by acids in the
stomach and no carbs are digested there. As the carbs enter the small intestine,
what remains is broken down by pancreatic amylase. Disaccharides are broken into
monosaccharides by the enzymes maltase, sucrase and lactase. The small intestine
completes digestion as all monosaccharides enter the bloodstream. Any carbs that
pass into the large intestine undigested, are fermented by bacteria, while other
carbs in the form of fiber, carbs that our body can’t digest, exits the body as waste.
The liver accepts the monosaccharides via the portal vein and it converted to
glucose which is the cells energy source. Extra glucose is then stored in the muscles
as glycogen and in the liver.
We need carbohydrates to survive. They are our bodies’ main fuel source and are
easily used as energy. They play a key role in our body’s central nervous system,
kidneys and brain. Fiber is key to maintaining intestinal health and in waste
elimination. 3
Unfortunately, carbohydrates have been given a bad rap by some. As our nation
battles the obesity epidemic, fad diets and quick fix solutions have invaded our
culture. Many diets seek to eliminate carbs as much as possible giving the body only
two of the macronutrients it requires, protein and fat. This requires the body to
break down protein tissue to make glucose or convert protein to glucose. 4 As a
result of this overweight status we have put ourselves into, doctors are reporting
record numbers of cases of type 2 diabetes among adults and even more alarming,
children. What is diabetes? Type 2 diabetes is the most common form of diabetes
and is a condition where “either the body does not produce enough insulin or the
cells ignore the insulin”5. Insulin is a hormone produced by the pancreas that aids in
the transport of the sugar from the blood to the cells. When this function is
disrupted, the cells don’t get the energy they need and the high glucose levels in the
blood may have a lasting, damaging effect on the eyes, kidneys, nerves or heart.
Carbohydrates raise the blood sugar, which can be a serious issue for the type 2
diabetic.
It is important for the diabetic to know what kind and how much
carbohydrate they are consuming. In a recent study published by the American
Journal of Clinical Nutrition, the study showed “that, under conditions of carbohydrate
restriction, fuel sources shift from glucose and fatty acids to fatty acids and ketones, and
that ad libitum–fed carbohydrate-restricted diets lead to appetite reduction, weight loss,
and improvement in surrogate markers of cardiovascular disease”6. The
results
in
conclusion are that “LCDs improve glycemic control and insulin resistance in healthy
persons and in persons with type 2 diabetes. The instruction to limit carbohydrate
intake, without specific reference to calorie intake, leads to a spontaneous reduction
in calorie intake”6.
-Application to Dietetic Practice
Nearly 26 million Americans have diabetes but the good news is that diabetes can
be managed or prevented with a few lifestyle changes.7 As a future dietician,
knowing the ins and outs of managing diabetes and what foods can help diabetics
live a long healthy lifestyle, is vital. Following a low carbohydrate diet may even
reverse the diagnosis and be an effective treatment plan for diabetics. As stated,
carbohydrates are vital to cells and are our body’s preferred fuel source. Educating
the clients on nutritious balanced meals and counting carbohydrates will be
essential to a successful practice.
Carbohydrate
Glucose
Pyruvate
Acetyl CoA
TCA Cycle
Electron Transport Chain
ATP
Water
References
1. Thompson J, Manore M, Vaughan L. Thompson, The Science of
Nutrition_3. Benjamin Cummings; 2013: 118
2. Sareen S. Gropper, Jack L. Smith. e-Study Guide for: Advanced
Nutrition and Human Metabolism by . Wadsworth Publishing;
2013: 63
3. McKinley Health Center. Macronutrients: The Importance of
Carbohydrates, Protein, and Fat website. Available at:
http://www.mckinley.illinois.edu/handouts/macronutrients.htm.
Accessed October 18, 2013.
4. Reviews CT. e-Study Guide for: Understanding Nutrition by
Eleanor Noss Whitney, ISBN 9780538734653. Cram101 Textbook
Reviews; 2012.
5. Diabetes Basics. American Diabetes Association website. Available
at: http://www.diabetes.org/. Accessed June 22, 2013.
6. Westman Eric. Low-carbohydrate nutrition and metabolism. Am J
Clin Nutr 2007 web site. Available at
http://ajcn.nutrition.org/content/86/2/276.full.pdf
7. Diabetes. Eat Right website. Available at:
http://www.eatright.org/Public/list.aspx?TaxID=6442452078.
Accessed October 18, 2013.