Carbohydrates in Your Body...in Your Diet

Since the 1970's, the traditional diet, with carbohydrates as the foundation, has been touted as the leading cause of the rise in obesity rates in the United States. But is the culprit all carbohydrates or refined carbohydrates? The refining process alters the natural composition of sugars and grains, reducing the amount of fiber and micronutrients that the body needs for optimum health. There is a clear indication of the connection between the increased consumption of refined sugars and carbohydrates and the rise in obesity and obesity related diseases, the simple truth remains that carbohydrates are not the evil they have been purported to be. Carbohydrates, the right kind of carbohydrates, are needed by the body not only for quick and long term energy needs but also to maintain normal bodily functions and a healthy gastrointestinal tract.

What are carbohydrates?

The right carbohydrates are essential to a healthy diet. Technically speaking, carbohydrates are chemical compounds of carbon, hydrogen, and oxygen. Carbohydrates include sugars, starches, and fibers. Carbohydrates are either simple or complex. Carbohydrates are broken down into single units in the digestive tract where they are absorbed and transported to the liver, used as energy, or converted into glucose and stored for quick use. The main purpose of carbohydrates is to provide the body with energy, mainly from glucose (sugar). (Grosvenor & Smolin, 2006)

Simple Carbohydrates

What are simple carbohydrates? Sugars are simple carbohydrates or simple sugars because they are composed of monosaccharides (one basic carbohydrate unit); when two monosaccharides combine they form disaccharides. The three most common monosaccharides are glucose, fructose, and galactose; although differing in arrangement, each are composed of 6 oxygen, 12 hydrogen, and 6 carbon atoms. Glucose, also known as blood glucose, is the simple sugar most people are familiar with and is rarely found in food as a monosaccharide. Fructose, much sweeter in taste than glucose, is found in fruits, vegetables, and honey. Galactose, like glucose, is rarely solitary, and is usually consumed in the diet as the disaccharide lactose found in milk. (Grosvenor & Smolin, 2006)

The three most common disaccharides are maltose, lactose, and sucrose. Galactose combines with glucose (both monosaccharides) to make the disaccharide lactose, the only sugar naturally occurring in animal foods. Maltose, the combination of two glucose molecules, is formed by the breakdown of starches. Sucrose, more commonly known as table sugar, is made by the combination of glucose and fructose. Healthy simple carbohydrates can be found in pineapples, melons, and honey in addition to many other vegetables and fruits. (Grosvenor & Smolin, 2006)

Complex carbohydrates

What are complex carbohydrates? Starches and fiber are complex carbohydrates that consist of chains of multiple sugar units joined together and usually do not taste sweet. The composition and length of the chains determine the role they play in food and the body. There are two classifications of chains: oligosaccharides and polysaccharides. Oligosaccharides are chains of three to ten monosaccharides and naturally occur in onions and legumes and may taste a little sweet. Polysaccharides, like the name suggests, are many chains of sugars and are contained in animal glycogen, starches, and plant fibers. (Grosvenor & Smolin, 2006)

Glycogen is carbohydrate that gets stored in the muscles and liver; it consists of many branches on glucose molecules enabling it to be broken down quickly when needed for energy. Plants store carbohydrates as starch for use as energy to enable reproduction and growth; starch is the combination of glucose molecules in straight or branched chains. Potatoes, beets, yams, and sweet potatoes are a few examples of stored plant energy that we eat and are good sources of complex carbohydrates. (Grosvenor & Smolin, 2006)

Fiber

The other complex carbohydrate is fiber; fiber is either soluble or insoluble. Dietary fiber is plant materials that the body is unable to digest. Fiber has many benefits to the body including maintaining digestive health, lowering cholesterol levels, and lowering the risk of cardiovascular disease; however, the main function of fiber is to regulate the digestive system (American Heart Association, n.d.). Soluble and insoluble fiber are found in oats, barley, legumes, beans, broccoli, apples, oranges, prunes, grapefruit, and many other vegetables, fruits, and grains; although, some sources are better than others, not only because some sources provide more fiber than others, but also because some sources contain both soluble and insoluble fiber. (Horn, 1997)

Adults are recommended to consume 25 grams or more of fiber per day. Children should consume five grams of fiber in addition to one gram of fiber for each year of age after age five each day; to give an example, a 10 year old child would need 10 grams of fiber per day (5 grams for up to the age of five plus five grams for each year from age five through ten). (Horn, 1997)

Soluble Fiber

Soluble fiber is characterized by its ability to swell with water in the intestines. Soluble fiber dissolves in water and forms a gelatinous solution in the intestines holding water which increases the weight of bowel movements and can be digested in the large intestine by bacteria facilitating the production of fatty acids and the much dreaded gas. Oats, apples, and beans are good sources of soluble fiber. (Grosvenor & Smolin, 2006)

Insoluble Fiber

Insoluble fiber cannot be digested in the gastrointestinal tract; therefore, it exits the gastrointestinal tract without changing. Instead, insoluble fiber adds bulk or substance to bowel movements making them easier to eliminate. Insoluble fiber assists in controlling caloric intake, by slowing the emptying of the stomach. Insoluble fibers are the structures of plants like the cell walls; good sources of insoluble fiber are wheat, bran, celery, cauliflower, and broccoli. (Grosvenor & Smolin, 2006)

Disorders Related to Carbohydrates

There are several diseases and disorders that are linked to eating certain carbohydrates. Let us examine the role carbohydrates play in lactose intolerance, diabetes, and hypoglycemia.

Lactose Intolerance

Lactose intolerance is the inability to digest the sugar lactose. Babies are usually able to produce the enzyme lactase, but the ability to make lactase decreases with age, declining so much in some individuals that lactose cannot be digested completely. When lactose cannot be digested, it is metabolized by bacteria in the large intestine creating acids and gas that pull water into the intestine creating abdominal discomfort and pain in the form of gas, cramping, diarrhea, and abdominal distention. (Grosvenor & Smolin, 2006)

Lactose intolerance can be a temporary condition brought on by disease or intestinal infection. For some, spreading lactose sources (primarily dairy products) throughout the day can reduce or prevent symptoms. If no lactose can be tolerated, other sources of calcium must be consumed to prevent deficiency or lactase tablets can be used to assist in digesting lactose prior to it reaching the intestine. (Grosvenor & Smolin, 2006)

Diabetes

Diabetes occurs when the blood glucose levels remain elevated due to the lack of insulin (Type 1 Diabetes) or when the body reduces or stops responding to insulin (pre-diabetes, gestational diabetes, and Type 2 Diabetes). Left uncontrolled, diabetes can cause irreversible damage to the eyes, nerves, heart, blood vessels, and kidneys.

An auto-immune disease, Type 1 Diabetes occurs usually before the age of 30 and the body stops making insulin due to destruction of the pancreas cells that secrete insulin. Type 2 Diabetes is most common, and is typically caused by a decrease in the cell's sensitivity to insulin, causing blood glucose levels to rise since the glucose cannot enter the cells properly. Type 2 Diabetes is believed to be caused by a combination of genetics and poor lifestyle choices. Pre-diabetes is a condition characterized by blood glucose levels that run higher than normal but not high enough to qualify as Type 2 Diabetic. Pre-diabetes is a warning, but can be reversed by monitoring diet and increasing exercise. Gestational diabetes occurs in pregnant women and presents a risk to the unborn child. It is presumed to be caused by hormone changes and typically disappears after the baby is born and hormone levels have returned to normal; although, after having Gestational Diabetes, there remains an increased risk for developing Type 2 Diabetes. (Grosvenor & Smolin, 2006)

Symptoms of diabetes include frequent thirst, urination, and blurred vision. Poor control of blood glucose levels lead to long term organ and tissue damage. Treatment includes a healthy diet, regular exercise, and oral medication. In the more advanced stages of diabetes insulin shots may be necessary in addition to oral medications. (Grosvenor & Smolin, 2006)

Hypoglycemia

Hypoglycemia is when the body's blood glucose levels drop too low. Symptoms include sweating, shaking, irritability, nervousness, anxiety, headache, hunger, weakness, rapid heartbeat, seizures, and sometimes coma. Hypoglycemia can occur in diabetics and persons without diabetes. In diabetics, hypoglycemia can be caused by over-medicating or an imbalance in carbohydrates and insulin levels. Treatment consists of consuming a carbohydrate that is digested quickly followed by a balanced meal within 30 minutes of the episode. In non-diabetic persons, hypoglycemia is caused by abnormal hormone production or the body's response to insulin. Reactive hypoglycemia follows consumption of a food high in carbohydrates causing a release of too much insulin, resulting in a fast drop of blood glucose levels. Treatment includes consuming small frequent meals that are high in protein and fiber, but low in simple carbohydrates. Fasting hypoglycemia, results from abnormal insulin release causing low levels of blood glucose, and is frequently caused by pancreatic tumors. (Grosvenor & Smolin, 2006)

The benefits that carbohydrates provide to the body are really too many to list here, but the most important are the use of fiber in the diet and the body's use of carbohydrates for energy. Indigestible carbohydrates increase bulk and fluids in the feces making them easier to pass; it also facilitates an increase in peristalsis: involuntary muscles that control movement through the gastrointestinal tract and reduce transit time. A high fiber diet reduces the absorption of glucose helping to maintain steady blood glucose levels; however, too much fiber can also decrease the absorption of essential vitamins and minerals. The body turns most carbohydrates into sugars to provide energy and fuel for the body's processes and activities. A healthy diet should derive most carbohydrates from whole sources such as whole grains, vegetables, and fruits.

References

American Heart Association. (n.d.) Heart & stroke encyclopedia: Fiber. Click here.

Horn, L. V. (1997). Fiber, lipids, and coronary heart disease: A statement for healthcare professionals from the Nutrition Committee, American Heart Association. Click here.

Grosvenor, M. B., & Smolin, L. A. (2006). Nutrition: Everyday choices. New Jersey: John Wiley & Sons, Inc.