The Carbohydrates:

Sugars, Starches, and Fibers

Chapter 4

Chapter Summary

            The simple carbohydrates include the monosaccharides (glucose, fructose and galactose) and the disaccharides (sucrose, maltose and lactose). The complex carbohydrates include the polysaccharides (glycogen, starch and fiber).

            Carbohydrate digestion involves hydrolyzing bonds to absorbable forms.  This process begins in the mouth and continues through the stomach and small intestine. Fibers are not digested. Carbohydrates that are absorbed circulate to the liver, where cells convert the compounds to glucose.

            Some individuals lack lactase - the enzyme responsible for the digestion of lactose. This is characterized by bloating, gas, abdominal discomfort and diarrhea upon the consumption of lactose-containing foods.

            The main function of glucose in the body is to provide energy. Glycogen is the storage form of glucose - found only in the liver and muscle cells. Glucose can be made from protein. Extra glucose can be converted into fat. The homeostasis of blood glucose is important for health. Hormones that help to maintain blood glucose in the normal range include insulin, glucagon and epinephrine.

            Sucrose poses no major health concerns except for increased risk of dental caries. It may be associated with nutrient deficiencies. Sugar does not cause obesity, heart disease, misbehavior in children nor criminal behavior in adults. It is recommended that the diet contain no more than 10% of total kCalories from refined sugars.

            Health effects of starch and fiber include weight control, low blood pressure, decreased risk of some forms of cancer, better control of diabetes and improved GI functioning. Excessive fiber may result in abdominal discomfort, low nutrient availability and bulk production.

            Highlight 6 classifies the list of FDA approved artificial sweeteners, their properties and allowable intakes and uses. Safety aspects and benefits of artificial sweeteners are discussed. Advantages and disadvantages of sugar alcohols are provided.


Chapter Outline                                                          


I.           The Chemistís View                               

II.          Simple Carbohydrates                               

A.       Monosaccharides                                        

1.        Glucose              

2.        Fructose             

3.        Galactose              

B.       Disaccharides                                         

1.        Condensation               

2.        Hydrolysis            

3.        Maltose                 

4.        Sucrose              

5.        Lactose                 

III.        Complex Carbohydrates                                                                                   

A.       Glycogen                                                  

B.       Starches                                                                                                                              

C.       Fibers                                                         

1.        Cellulose              

2.        Hemicellulose

3.        Pectins

4.        Gums and mucilages

5.        Lignin

6.        Other classifications         

IV.      Digestion and Absorption                      

A.       Processes

1.        Mouth            

2.        Stomach            

3.        Small intestine              

4.        Large intestine              

5.        Absorption in bloodstream        

B.       Lactose Intolerance                                   

1.        Symptoms

2.        Causes               

3.        Prevalence

4.        Dietary changes         

V.       Glucose in the Body

A.       Carbohydrate Metabolism                         

1.        Storing glucose as glycogen

2.        Using glucose for energy

3.        Making glucose from protein   

4.        Making ketone bodies      

5.        Converting glucose to fat

B.       Blood Glucose Constancy

1.        Glucose homeostasis      

2.        Regulating hormones        

3.        Balancing within normal range

4.        Outside normal range

5.        Diabetes            

6.        Hypoglycemia              

7.        Glycemic effect          

VI.      Health Effects and Recommended Intakes of Sugars                              

A.       Health Effects of Sugar

1.        Nutrient deficiencies      

2.        Dental caries            

B.       Accusations about Sugar

1.        Obesity

2.        Heart disease

3.        Misbehavior and criminal behavior

C.       Recommended intakes of sugar

VII.    Health Effects and Recommended Intakes of Starch and Fibers

A.       Health Effects of Starch and Fiber

1.        Weight control

2.        Heart disease

3.        Cancer

4.        Diabetes

5.        GI health         

6.        Harmful effects of excessive fiber                  

B.       Recommended Intakes of Starch and Fiber

1.        Choose variety

2.        Read food labels

VIII.   Highlight: Alternatives to Sugar               

A.       Artificial Sugars                                             

1.        Saccharin            

2.        Aspartame              

3.        Acesulfame-K              

4.        Sucralose              

5.        Alitame, cyclamate           

6.        Acceptable daily intake        

7.        Weight control

B.       Sugar Replacers                                               

1.        Sugar alcohols         

The University of Texas at Brownsville & Texas Southmost College
For comments or more information, contact Gerson Peltz.