Digestion And Macronutrients Essay

Digestion And Macronutrients Essay

TOPIC 1: Dietary fat has been vilified. Is this a correct characterization of this macronutrient? Is all fat bad? What types of fats can we find in our diet (go beyond our textbook)?

Most be at least 250 words and at least 2 reference Digestion And Macronutrients Essay


1. Essay: The Digestive and Absorption Processes of Macronutrients
Whenever we eat, the foods we ingest in our bodies undergo different processes in order to put
resourceful nutrients to work and eliminate unnecessary waste products. In regards to utilizing nutrients
from foods for the body, processes such as digestion and absorption are involved. Digestion is when foods
are broken down into components, and absorption is when these products of digestion are moved through
the small intestine walls and overall into circulation of the body. These processes correlate to everything
we eat, which includes macronutrients. Macronutrients, in particular, are the nutrients in which a living
organism needs in huge amounts for effective growth and development. The three main macronutrients
consist of: lipids, carbohydrates, and proteins.
Lipids are one group of macronutrients. Lipids are a diverse class of molecules in which are
insoluble in water, meaning that they do not dissolve in the presence of water. Fats, in particular, are one
type of lipid. There are three different kinds of lipids found in foods: triglycerides, phospholipids, and
sterols. In essence, the role of fat in our body is to provide energy and energy storage for later usage. Digestion And Macronutrients Essay
The digestion and absorption of fats are not done easily as fats are insoluble, but these processes do
happen primarily in the small intestine. The process of digestion for fats first starts off in the mouth, as
salivary glands produce an enzyme called “lingual lipase”. This particular enzyme digests some
triglycerides that can be found within the fats being ingested. As the food is swallowed, it moves along into
the stomach. The intact food is then mixed and broken down into particles/fat droplets. The stomach also
releases gastric lipase, which aids in digesting some more triglycerides. At this point, however, a lot of
digestion has not taken place. The gallbladder releases bile into the small intestine, and chyme (containing
fat molecules) also passes slowly into the small intestine. The bile from the gallbladder helps to emulsify
the fat, alongside pancreatic enzymes that derive from the pancreas. These pancreatic enzymes help to
break triglycerides into monoglycerides and fatty acids. Then, the spherical micelles found in the small
intestine help to transport free fatty acids to the mucosal cells for absorption processes. Within these
mucosal cells, a small amount of protein is involved, and is added to the lipids ­ and this overall creates
chylomicrons, which are lipoproteins produced by the cells that line the small intestine. Chylomicrons are
considered to be the transport system that help remove fats and overall travel through the lymphatic
system, along with being transported into the bloodstream. In order to get through these systems and cells,
the triglycerides in the chylomicrons are once again broken down into two fatty acids and a monoglyceride
with the help of lipoprotein lipase. Once entering the cell membrane, the broken down fatty acids and
monoglyceride reform a triglyceride structure again. This is where the triglyceride can be utilized for the
body, either for immediate energy use, to make lipid­containing compounds, and/or for storage in the
muscle and liver cells. The remaining fats can also be stored as “adipose tissue” (fat cells) within the
body. As for elimination of waste products that involve fats, the undigested lipids move along to the large
intestine.The intestinal bacteria in the large intestine helps to break down the undigested lipids into waste
products (feces).
Carbohydrates are another group of macronutrients that are mainly derived from plant foods (e.g.
fruits, vegetables, and grains). In essence, carbohydrates can be classified as simple and complex. Within
these two categories, there are many different types of carbohydrates involved. These various
carbohydrates are digested and absorbed within the body through various steps. Carbohydrate digestion
starts from the mouth and salivary amylase is produced from saliva. The salivary amylase starts off the
process by breaking down the starch (glucose molecules) into maltose, a disaccharide. Once the food is
ingested, the produced maltose goes to the stomach. The acidic content of the stomach causes the maltose
to become non­functioning and shapeless. Although the content might go to the stomach, carbohydrates do
not get digested via the stomach. Like lipid digestion, carbohydrate digestion also occurs mainly in the
small intestine. The pancreas also helps by secreting pancreatic amylase into the small intestine, in order
to break down starch found in the carbohydrates. As chyme enters the small intestine, the pancreatic
amylase hydrolyzes starch into maltose effectively (unlike the stomach). The small intestine also helps to
break down disaccharides into monosaccharides through certain enzymes. Then, these converted
monosaccharides are all absorbed by the small intestine and overall enter the bloodstream. Through the
bloodstream, these monosaccharides transfer over to the liver. The liver is where all the monosaccharides
are then converted to glucose, and this glucose is spread out to different cells of the body for energy
purposes. The remaining glucose, converted to glycogen, is then stored in the liver. Overall, the remaining
(undigested) carbohydrates transport over to the large intestine. As we humans do not contain the bodily
enzymes to digest fiber, the large intestine helps in breaking down some fiber structures. The large
intestine contains intestinal bacteria that helps to break down the undigested carbohydrates, overall
excreting it out of the body as feces. Digestion And Macronutrients Essay
Proteins are the third type of macronutrients, and they are large and complex molecules that are
made up of amino acids. Proteins are the primary source of nitrogen within our diets, and the digestion and
absorption of proteins includes extensive steps as well as the other two macronutrients. The digestion of
protein starts off in the mouth, where the proteins found in the food are broken down by salivary glands in
saliva and chewing. This breakdown of food is then moved along to the stomach, where protein digestion
essentially begins. The hydrochloric acid found in the stomach helps break down protein structure, also
activating pepsin. Pepsin also helps to deconstruct proteins into single amino acids and smaller
polypeptides. The chyme overall moves along to the small intestine, where digestion continues, and
pancreatic proteases help to digest the polypeptides into even smaller particles. The liver overall
effectively digests the proteins, as the cells found in the wall of the small intestine complete breaking down
polypeptides into single amino acids. The single amino acids then are transferred over to the liver,
monitoring their metabolism and overall sending them out throughout the cells in the body as needed. The
remaining dietary protein is eliminated by the help of the large intestine and its intestinal bacteria that helps
to break down remaining proteins into feces.

Module 2 Written Assignment

1. What are enzymes? What specifically is the role of an enzyme in digestion?

Enzymes are working proteins that facilitate chemical reactions without being changed in the process. Organs of the digestive system excrete digestive juices, which contain enzymes that break the bonds of nutrients that can be absorbed.


2. Trace the path of a cheeseburger and fries through the digestive tract. Indicate each place where mechanical digestion, chemical digestion, and absorption occurs FOR EACH NUTRIENT (carbohydrates, lipids, proteins). Be sure to fully explain the role of EACH organ involved (including the pancreas, liver, and gallbladder).

In the mouth – food is crushed and chewed by teeth (mechanical…show more content…
The small intestine also contributes enzymes to complete the digestion process before nutrients are small enough for the cells to absorb (chemical).
In the large intestine – The digestion and absorption of proteins, fats and carbohydrates are essentially complete by the time the intestinal contents enter the colon. Only water, fiber and some minerals remain. Only certain fibers can be broken down by bacteria (chemical digestion).The colon's task is mostly to reabsorb water and minerals, leaving a paste of fiber and feces for excretion (mechanical) via rectum and anus.

3. How is the lining of the small intestine protected from acidic chyme entering from the stomach?

The pyloric valve of the lower stomach regulates the amount of chyme that exits into the small intestine, allowing only a little at a time to exit. Also, once chyme enters the small intestine, hormonal messengers signal the pancreas to release alkaline pancreatic juice, bicarbonate, to neutralize the stomach acid that has reached the small intestine.

4. Where are carbohydrates stored in the body? In what form are carbohydrates stored?

If you frequent health forums or fitness blogs, you'll have read the word “macros” before. The word is short for macronutrients. That leads to the question, “what are macronutrients?”

The macronutrients a person consumes are what the body needs to function properly. They are the nutrients from protein, fats and carbohydrates that make up a person's daily nutrition. The amount of macronutrients and ratio of one to the other is what people alter to achieve a certain result. For example, lowering carbs and fats while amping up on protein is what body builders do to gain more muscle. Runners will lower protein while increasing carbs to give themselves a rush for a big races. Digestion And Macronutrients Essay

What is Protein?

You've probably heard about how influential protein is to gaining muscle, but it also gives you…show more content…
In terms of why your body needs fats from foods, it uses fat to absorb vitamins. Dietary fats will include saturated as well as unsaturated fats. One type of fat is good for your body and one isn't great at all. This is what can be confusing to most people who strive to remove fats from their diet when they're trying to lose weight.

Saturated fats come from animal sources like steak, hamburger and pork. Unsaturated fats are derived from plants. There are also trans fats that are considered poison for the body. They raise the bad cholesterol in your body, and should never be included in a healthy diet. There are also fatty acids like omega-3 and omega-6 that are good for a healthy body. Digestion And Macronutrients Essay

There should always be a balance between the good macronutrients. Even though you might want to eliminate fats from your daily intake, the USDA concludes that all of the macronutrients are vital in combination with the others. They advocate that daily calories from fats should account for 20-40% of the person's daily calories...Digestion And Macronutrients Essay