Fundamentals of Human Nutrition/Functions

From Wikibooks, open books for an open world
Jump to: navigation, search

Functions[edit]

Please use this HELP:EDITING link for information about contributing and editing the book.


2.3.1 Sugar and Starch[edit]

Carbohydrates are sugars, starches, dextrins, and gums. Both sugars and starches are classified as saccharide. Sugar is a simple carbohydrate with the chemical composition of (CH2O)n. Most sugars form ringed structures when in solution. Generally refers to as monosaccharides and disaccharides. Starch is a carbohydrate made of multiple units of glucose attached together in a form the body can digest; also known as complex carbohydrate.(1)

2.3.1.1 Energy[edit]

The simple sugars in foods that are most important to human nutrition are called sucrose, fructose, lactose, and maltose. The body needs the simple sugar called glucose, so these other simple sugars in food break apart in the body to become glucose which yields energy of 4Kcal per gram of carbohydrate. They do this by coming apart easily at the water connections. Starches include such foods as potatoes, cereals, wheat and other grains, and rice. Starches are complex sugars, and complex sugars break down into one of the simple sugars (maltose), and then to glucose by easily breaking apart at the water connections. Essentially, starches are sugars that merely require a few more steps to make them into glucose.

2.3.1.2 Lipid metabolism[edit]

Lipids are absorbed from the intestine and undergo digestion and metabolism before they can be utilized by the body. Most of the dietary lipids are fats and complex molecules that the body needs to break down in order to utilize and derive energy from.(2)

Short chain fatty acids enter the circulation directly but most of the fatty acids are reesterified with glycerol in the intestines to form triglycerides that enter into the blood as lipoprotein particles called chylomicrons.

Lipoprotein lipase acts on these chylomicrons to form fatty acids. These may be stored as fat in adipose tissue, used for energy in any tissue with mitochondria using oxygen and reesterified to triglycerides in the liver and exported as lipoprotein called VLDL (very low density lipoproteins).

VLDL has a similar outcome as chylomicrons and eventually is converted to LDL (low density lipoproteins). Insulin simulates lipoprotein lipase.

During starvation for long periods of time the fatty acids can also be converted to ketone bodies in the liver. These ketone bodies can be used as an energy source by most cells that have mitochondria.


Reference

1. What are sugars and starches – By Dr. Beth Gruber, published on July 29, 2003 at www.carbsmart.com

2. Lipid Metabolism – By Dr. Ananya Mandal, MD, published in http://www.news-medical.net/health/Lipid-Metabolism.aspx

3. [1]

2.3.2 Fiber[edit]

2.3.2.1 Glucose balance[edit]

Abstract The current research of glucose balance is ever increasing in breadth and depth of understanding. Glucose balance is a hot topic and includes the major illnesses of obesity and diabetes. From glucose supplements, hip contemporary healthy ‘how- to’ books, notable lectures and nutritional philosophies; glucose is certainly the topic of the day. It has been a curious process to find a starting point in which to explain the central concept of glucose balance while sifting through the morass of data. This brief unscientific overview is aimed at the fundamentals of what glucose is, why we need it and a general sense of what happens when we have too little or too much of this life giving simple sugar.   Glucose Balance:

Glucose is a simple sugar derived from carbohydrates in our food [1]. A steady supply of glucose provides our body with an energy source in which to support healthy functioning and life. Too much or too little glucose in our blood stream can have unhealthy effects to our body. Staying in balance supports healthy functioning. [2] Glucose balance (glucose homeostasis or blood sugar regulation) is dependent upon two hormones, glucagon and insulin [3]. The presence of these hormones regulates the absorption of glucose. [1] Insulin allows absorption of glucose and glucagon stimulates the liver to release more glucose . Our brain and muscle tissue are primary receivers of glucose and utilize it as an energy source. When glucose is not absorbed for energy use, it is deposited into fat cells as storage. A simple diagram found in a journal of Nature shows how this is coordinated between the liver, pancreas and other organs in the body [4]. Finding the right glucose balance is specific to your unique genetic disposition. Talking with your doctor can provide clues to what your balance would look like. Healthy eating practices and eating nutritionally dense foods are continually stressed throughout the research on glucose. And there is little, if at all, research finds that symptoms of an unbalanced glucose balance yield desirable outcomes for people [5]. Two major conditions with evidence pointing to blood glucose are diabetes [6] and obesity. Obesity researchers are finding how the brain senses glucose and how this is linked to obesity and metabolism. [7] Where can we find glucose and what food choices are better for us to consume? These are both broad questions and will not be the focus of this short study. However, there can be some quick comments made to examine this question. Understanding carbohydrates and digestion of carbohydrates will aid in the choices you make. [8] Since carbohydrates are mainly found in plants, consider the fiber intake of these plant based carbohydrates. [9]It is suggested that glucose absorption can be influenced by the fiber you are consuming. And eating whole foods, fiber and all, will aid in the proper balance of glucose in most people’s diets. [10]

References http://en.wikipedia.org/wiki/Glucose http://www2.jabsom.hawaii.edu/pili/curriculum/pic/PiC_Mtg03_Food.pdf http://www.wisegeek.com/what-is-glucose-homeostasis.htm http://www.nature.com/nature/journal/v444/n7121/fig_tab/nature05483_F3.html http://www.med.umich.edu/pfans/docs/tip-2013/bloodsugarbalance-0313.pdf http://www.diabetes.org/ http://www.diabetes-obesity-center.org/?q=faculty/schwartz-md Hyman, Mark MD, (2012). The Blood Sugar Solution: the ultrahealthy program for losing weight, preventing disease, and feeling great now! 1st ed. Little, Brown and Company.New York, New York. http://www.livestrong.com/article/387923-how-do-we-get-glucose/ Robertson, Laurel, (1986). The New Laurel's Kitchen. 1st ed. Berkeley, California: Ten Speed Press.

2.3.2.2 Gut health[edit]

2.3.2.3 Cholesterol balance[edit]

  1. a b http://en.wikipedia.org/wiki/Glucose
  2. http://www2.jabsom.hawaii.edu/pili/curriculum/pic/PiC_Mtg03_Food.pdf
  3. http://www.wisegeek.com/what-is-glucose-homeostasis.htm
  4. http://www.nature.com/nature/journal/v444/n7121/fig_tab/nature05483_F3.html
  5. http://www.med.umich.edu/pfans/docs/tip-2013/bloodsugarbalance-0313.pdf
  6. http://www.diabetes.org/
  7. http://www.diabetes-obesity-center.org/?q=faculty/schwartz-md
  8. Hyman, Mark MD, (2012). The Blood Sugar Solution: the ultrahealthy program for losing weight, preventing disease, and feeling great now! 1st ed. Little, Brown and Company.New York, New York.
  9. http://www.livestrong.com/article/387923-how-do-we-get-glucose/
  10. 5. Robertson, Laurel, (1986). The New Laurel's Kitchen. 1st ed. Berkeley, California: Ten Speed Press.