• Distinguish among the various carbohydrates found in foods and in the human body.
• Describe the body’s use of glucose to provide energy or to make glycogen and fat.
• Discuss diabetes, hypoglycemia, and lactose intolerance and their relationship to carbohydrate intake.
• Discuss the roles of fiber-rich foods in the maintenance of the boy’s health and identify foods rich in fiber.
• Assess the role alternative sweetener play in one’s diet.

No human carbohydrate deficiency disease has ever been identified, yet prolonged lack of carbohydrates in human diets will result in intestinal problems and disturbances in metabolism. Also, dietary fiber intake may be negatively correlated to incidence of cancer, especially colon cancer.

The natural process for the creation of glucose takes place in green plants. The process is called photosynthesis because it uses energy from light to accomplish the chemical condensation of six H₂O molecules and six CO₂ molecules to produce one C₆H₁₂O₆ molecule (glucose) and six molecules of O₂ (oxygen gas).

---

The chemical reaction is: 6H₂O + 6CO₂ C₆H₁₂O_{6 +} 6O₂

Chlorophyll is the green pigment that captures the light energy for the process.

The Important Polysaccharides are made up of many (possibly thousands) of monomer units.

Starch	Plant glucose, storage molecules (amylose - straight chain starch, amylopectin - branch chain starch)
Glycogen	Animal glucose, storage molecules
Cellulose	Plant structural material from glucose, polymerized differently than in starch (fiber)

water soluble fiber - called pectins and pectic acids, gums and mucilages
water insoluble fiber - called cellulose, hemicellulose and lignin

Characteristics of fiber in human health and disease

Fiber and the Colon

Benefits

• Provides feelings of fullness
• Reduces colon cancer
• Displaces calorie dense foods
• Prevents diverticulosis
• Prevents constipation
• Lowers blood cholesterol
• Prevents hemorrhoids
• Slows carbohydrate absorption
• Prevents appendicitis

Advantages

• Delays nutrient absorption rates
• Delays sterol absorption
• Stimulates bacterial fermentation in the colon
• Increases water binding in stool

Disadvantages 

• Can cause dehydration by binding and carrying away water
• May speed up transit time, and thereby reduce absorption of certain substances
• Chelation of minerals may reduce their bioavailability.

Absorption of carbohydrates - Microvillli are finger-like projections in the small intestine which increase the surface area of the absorptive area to up to 200 m² in humans. A number of saccharidases are attached to the microvilli, it is these enzymes that hydrolyze the starch fragments to monosaccharides in preparation for absorption by the microvilli.
After monosaccharides are absorbed into the bloodstream the liver takes them up. Fructose and galactose are converted to glucose. Glucose is used at once for energy, or polymerized to glycogen for storage, or converted to fat for storage.

Malabsorption - The failure to absorb carbohydrate in the proper manner at the proper site may be due to a congenital condition (lactose intolerance or hypolactasia) or a disease such as cancer.

The body’s use of glucose:

• Energy - directly in such processes as thermoregulation, metabolism and motion.  Carbohydrate is the most preferred fuel for the body.
• Storage (as glycogen) - In liver and muscle cells, energy is stored as glycogen. The pancreas releases insulin into the blood as response to the increase of blood sugar, which is the result of sugar absorption from the villi.
• Storage (as fat) – Once the liver and cells have stored the maximum amount of glycogen, excess glucose is broken down to 2 carbon fragments and reassembled as fatty acids. These fatty acids are converted to triglycerides and stored in the body in unlimited quantities as fat. That is why excess carbohydrate calories are just as bad for you as excess fat calories.
• Release (as glucose) - Low blood sugar levels cause the pancreas to release glucagon, which stimulates the liver to hydrolyze glycogen and release glucose into the blood. Muscle glycogen is not available for the release of glucose into the blood. Muscle glycogen can only be used for energy by that particular muscle group.

Insulin regulation of blood sugar

Blood glucose levels are maintained in the blood by the hormone activity of insulin and glucagon. These two hormones are synthesized in the pancreas.  If this control is lost due to pancreatic disease or impaired action of the insulin, blood glucose rises and diabetes is the result!

Table 4-7 (Page 113) compares the two common types of diabetes.

Diabetes Mellitus - Type I (IDDM) and Adult Onset Diabetes - Type II (NIDDM)

• Warning Signs
  - excessive urination
  - glucose in the urine
  - easy tiring, weakness, irritability
  - cravings for sweets
  - frequent infections of skin and mucosal membranes
  - vision problems
  - pain in feet, legs and hands
  - drowsiness
  - itching

One important symptom that differs between IDDM and NIDDM is the onset of IDDM is associated with weight loss, and the onset of NIDDM is associated with weight gain

Warning signs for both: headaches and fatigue

The Bread, cereal, rice or pasta group provides about 15 grams, mostly starch.

The Vegetables group provides about 5 grams, as a mixture of sugars and starch.

The Fruits group provides about 15 grams, mostly as sugars.

The Milk, cheese and yogurt group provides about 12 grams, mostly sugar, while other dairy products have less carbohydrate (cheeses).

What is the truth about sugar?

The following are disorders in which sugar has been named the culprit.

What is the truth? Study each claim, and carefully assess the evidence.

Artificial Sweeteners - Good or Bad?

Acesulfame-K - no evidence of health effects
Cyclamate - rat cancer suspected, never proven
Aspartame - no evidence of health effects
Saccharin - bladder cancer increased in rats
Sucralose - non-caloric, not absorbed
Alitame - similar to aspartame, no evidence of health effects

These chemicals probably pose little threat if used in moderation, especially if you are healthy to start with.