Carbohydrates
Macronutrient
An energy-yielding nutrient. Macronutrients are those
nutrients that together provide the vast majority of metabolic energy to an
organism. The three main macronutrients are carbohydrates, proteins, and fat.
Micronutrients
Microminerals or trace elements, are dietary minerals needed
by the human body in very small quantities (generally less than 100mg/day) as
opposed to macrominerals which are required in larger quantities.
Functions
Glucose it is the
most easily used by the body. It is a simple carbohydrate that circulates in
the blood and is the main source of energy for the muscles, central nervous
system, and brain (the brain can also use ketone bodies).
Carbohydrates are made of organic compounds carbon, hydrogen, and oxygen.
There are three sizes of
carbohydrate and they are distinguished by a classification of two that is, simple
carbohydrates (mono saccharides and disaccharides) and complex
carbohydrates (polysaccharides). Polysaccharides are the most abundant
carbohydrate in the body along with glycogen.
The break down of polysaccharides goes
as follows: Polysaccharides are digested into monosaccchorides including
glucose which goes into the intestinal epithelium and into the bloodstream. The
molecules of glucose are taken by glucose transporters and delivered into the
cells of the body. While glucose is in the cells it can be oxidized for energy
or provide substrates to other metabolic reactions or of course into glycogen
for storage.
A. Monosaccharides = Single
carbohydrate unit such as, Glucose, Fructose, and Galactose.
B. Disaccharides = Two single
carbohydrates bound together such as, Sucrose, Maltose, and Lactose.
C. Polysaccharides = Have many
units of monosaccharides joined together such as, Starch and Fiber.
Fiber
Fiber is carbohydrates that cannot
be digested. It is in all eatable plants such as fruits vegetables, grains and
Legumes. There are many ways of categorizing fiber types. First, from the foods
they come from such as grains, which is called cereal fiber. Second, if they
are soluble fiber or insoluble fiber. Soluble fiber partially dissolves in
water and insoluble fiber does not.
Adults need about 21-38 grams of
fiber a day. Children ages 1 and up need 19 grams a day. On average Americans
eat only 15 grams a day.
Fiber helps reduce the chances of
having the following conditions: colon cancer, heart disease, type 2 diabetes,
diverticular disease, and constipation.
Glycemic Index
Glycemic Index is a new way of classifying carbohydrates. It measures how fast and how far blood sugar will rise after consuming carbohydrates. Foods that are considered to have a high glycemic index are converted almost immediately to blood sugar which causes it to rise rapidly. Foods that are considered to have a low glycemic index are digested slower causing a slower rise in blood sugar. Examples of high glycemic index foods are potatoes, white rice, white flour, anything refined, anything with a lot of sugar which includes high fructose corn syrup. Examples of low glycemic index foods are whole grains (brown rice, 100% whole wheat bread, whole grain pasta, high fiber cereals), high fiber fruits and vegetables, and many legumes. According to the Harvard School of Public Health, "The most comprehensive list of the glycemic index of foods was published in the July, 2002, issue of the American Journal of Clinical Nutrition. A searchable database maintained by the University of Sydney is available online."
