Anatomy and Physiology
Our digestive system is a complex and yet amazing feature in our road to survival. The digestive system allows us to break down the foods we eat and use these foods as fuel for our everyday activities.
The two main ways in which we digest food is mechanically and chemically. Breaking apart the food without any digestive enzymes doe’s mechanical, where as, chemical digestion uses enzymes and digestive juices to break down the food into usable nutrients. Salivary glands produce digestive juices which aides in the digestion of food while in the mouth. Saliva contains an enzyme that begins to break down the starches and sugars in food into smaller particles. (Bronson, 2011)
The teeth break down the food down by a process called mastication. The process of mastication involves chewing, mashing, and breaking food down. This process prepares the food to be swallowed. The tongue also assists in this process by shaping the food into its shape to be safely swallowed. (Bronson, 2011)
In your mouth the salivary gland give off enzymes, which help to break down many of the foods we eat. The enzyme salivary amylase is used to break down starch into smaller glucose particles called “dextrins.” The smaller chains of starch, or dextrins, get further digested into polysaccharides and then maltose. (Waxman, 2015)
The stomach is a hollow, sac-like organ enclosed in a wall of muscle. (Bronson,2011) The stomach holds food for further digestions prior to the small intestine.
The stomach produces gastric juices that are secreted by the stomach lining. The stomach lining produces hydrochloric acid and pepsin, an enzyme that digests protein. The hydrochloric acid actively kills the bacteria taken in with food and creates an acidic environment for pepsin to work. (Bronson, 2011)
Small and Large Intestine
The small intestine is 20-23 feet long and consists of 3 parts: the duodenum, the jejunum, and the ileum. 90% of all nutrients are absorbed here. The inner wall of the small intestine contains millions of fingerlike projections called villi. Villi are lined with capillaries that absorb nutrients. Unabsorbed material is then moved to the large intestine via peristalsis (muscle like contractions which send food through the digestive tract). (Bronson, 2011)
Undigested parts such as fiber, or roughage pass through into the colon, or what’s better known as the large intestine. The large intestine is 5 to 6 feet in length and has a diameter of 2.5 inches. Its function is to absorb water, vitamins, and salt, while also eliminating waste. (Bronson, 2011)
6 Main Nutrients
We obtain energy from the foods we eat and the nutrients we receive from those foods. The six main nutrients are carbohydrates, proteins, fats, vitamins, minerals, and water. Without these basic rudimentary building blocks of nutrition our bodies would not receive the proper amount of nutrients it needs to maintain its proper functions.
Nutrients perform many functions throughout the body. Nutrients help in healing the body, sustaining growth, production of energy, helping transport oxygen to cells, and regulating body functions. (Bronson, 2011) Carbohydrate, proteins and fats all provide the body with a steady stream of energy. Each gram of carbohydrate and/or protein we eat it accounts for four calories of energy. Fats, however, account for 9 calories per gram when eaten. The body uses these nutrients to build, repair, and fuel itself.
The main role of carbohydrates in the body is to provide energy to working muscles, providing fuel for the central nervous system, enabling fat metabolism and preventing protein from being used as energy. Food containing carbohydrates are in the grains, fruits, and milk groups. Vegetables have a small amount of carbohydrates as well. (ISU, 2015)
Carbohydrates are broken down into two subcategories: simple and complex. Simple sugars are found in your fruits (juices), candy and sodas. These types of sugars are readily broken down and area easily digested into the small intestine. This allows for a more rapid spike in blood glucose levels and adversely an increased release of insulin. This energy is produced quickly, yet only lasts for a brief time. Complex carbohydrates better known as starches and fiber are more “complex” than the simple sugars and take longer to digest and absorb leading to a slower increase in blood glucose and similarly a slower and steadier increase in insulin levels. These types of foods include but are not restricted to bread, pasta, and whole grains.
Carbohydrates are broken down into smaller units of sugar (including glucose, fructose, and galactose) in the stomach and small intestine. These smaller units of sugar are absorbed into the small intestine and then entered into the blood steam where they then travel to the liver. The liver converts fructose and galactose to glucose. Glucose is then transported out to the various tissues and organs, including the muscles and the brain, where it is used as energy. (ISU, 2015)
What about when we sleep? Where not burning much energy, yet we just ate dinner a few hours prior to this act? What happens to this abundance of glucose then? The glucose not needed for energy is stored by the liver and skeletal muscle in a form called glycogen. If these areas are full and glycogen has no place to be stored glycogen is then stored as fat. (ISU, 2015)
In order for our bodies to actually absorb the particles from the foods we eat it must be broken down into very small pieces. When breaking down carbohydrates our mouth do the mechanical part of digestion, but what does our bodies do to get the food prepared for absorption? As stated in an article by Carlyne Waxman, “With the work of three digestive enzymes, carbs get broken down from polysaccharides to shorter glucose chains and disaccharides.” (Waxman, 2015) These enzymes are maltase, sucrase, and lactase. Maltase helps to break down the maltose into glucose; sucrase breaks down sucrose into fructose and lactase breaks down lactose into glucose as well. (Waxman, 2015)
Chemical Make Up of Sugar and Artificial Sweeteners
There are many different types of sugar and artificial sugars. The natural sugar found in most kitchens across the world is comprised of 12 carbon atoms, 22 hydrogen atoms and 11 oxygen atoms.
Sucrose is another name for a natural sugar and is found in most plants, but it occurs at concentrations high enough for economic recovery only in sugarcane. (Clarke, 2015)
Many people tend to eat these artificial sweetened foods because they are in fact “sugar free.” Thus, leading towards fewer calories. The fact of the matter is that even though these sweeteners claim to be calorie free they still contain some form of caloric intake. “The dextrose and maltodextrin that manufacturers use to bulk them up contain about a quarter of the calories found in sugar.” (Selim, 2005)
How can so many different structures all taste sweet? Unit very recently the answer was a mystery. “Thousands of sweet-tasting compounds belonging to more than 150 chemical classes have been discovered including low-molecular-weight carbohydrates, aminoacyl sugars, amino acids, peptides, proteins, terpenoids, sulfamates polyketides, and ureas.” (Selim, 2005) Scientists have known that taste buds have receptors, which react to all these compounds, but no one understood how they worked. One theory is that of synergy. Synergy is well known in drug design, which typically means two or more receptors working together.
A study conducted by Charles Zuker and Grant Dubois found that humans and rats have the 30 receptor taste buds devoted to bitter yet only one devoted to sweetness. (Selim, 2005) Grant Dubois is quoted as stating, “The theory being that there are a lot of varyingly toxic bitter compounds we have to distinguish between, but everything sweet can be lumped together as good.” (Selim, 2005) Zucker then wondered what would happen if each subunit had its own binding site? Our bodies have only one sweetness receptor, but it has more than one region that can be activated by different molecules. Dubois is quoted by saying, “It’s like having a gun with two triggers.” (Selim, 2005)
Chemical periodic table:
History of Artificial Sweeteners
You see sugar substitute packets everywhere you go, but what makes one different from the other? Here is the history of all of those artificial sweeteners. Saccharin was one of the first artificial sweeteners discovered in 1878 in the Johns Hopkins University Laboratory of Ira Remsen, a professor of chemistry at the school. At age 21 Remsen had graduated with honors from the College of Physicians and Surgeons at Columbia University. (Hicks, 2015) Saccharin was said to have no side effects at the time and better for you than regular sugar.
Remsen teamed up with another chemist in 1877 by the name of Constantin Fahlberg. Fahlberg found that if you add sulfobenzoic acid to phosphorus (V) chloride and ammonia it produces benzoic sulfinide. This compound had given Fahlberg the first commercially viable alternative to sugar cane. (Hicks 2015)
As saccharin use rose customers began to question its harmlessness. Tests analyzing the product in 1882 showed that it had barley any bodily response and was surprisingly passed unmetabolized into his urine. However, in 1906 congress had place into affect a law regulating the nations food supply. This law was called the, “Pure Food and Drug Act.” (Hicks 2015) The product was banned in 1908. In years to come this pattern went on to repeat itself. As medical evidence was increasingly supportive of the product and inconclusive of the harms it may cause the product was then publicized in the early 1970’s. (Hicks 2015)
As testing progressed, researchers decided to start using controlled groups. The research produced more data and better results in favor of saccharin usage. However, in 1972 the FDA stated that, “If it causes cancer, whether it’s 875 bottles a day or 11 it’s going off the market.” (Hicks 2015)
By 1977 a ban of Saccharin looked likely, but with the help of the public it was not nearly gone. The ban against these sweeteners gave way to a huge increase in saccharin sales. People were stocking up because of the ban being placed into effect. As stated by Hicks, “People spoke with their wallets.” (Hicks 2015)
The threat of a saccharin ban led producers to research alternatives. Saccharin was 300 times as sweet as regular sugar cane, but this gave way to a new generation of artificial sugars. More and more artificial sweeteners kept popping up: Aspartame in 1965, Sucralose in 1976 and in 2002 Neotame, 7000 times sweeter than sugar. (Hicks 2015)