Monday, September 14, 2015

Macro-and Micronutrients and Digestion


Minerals and Vitamins are micronutrients that are required in very small amounts by the body and serve a wide variety of purposes.  Some minerals can provide structure to the bones, regulate blood pressure, and keep the body’s immune system healthy.  The amounts of minerals and vitamins that are needed vary and are generally based upon a person’s amount of nutrients in his or her diet. 

            Water is the most essential nutrient that our bodies need and is required to keep our bodies healthy and functioning properly.  Water does many things for the body.  It is required for metabolism and energy storage, temperature regulation, helps the kidneys filter waste products from the bloods, and helps transport oxygen and vital nutrients to the cells in the body (Water, 2004).  2 to 3 liters of water or half a person’s body weight is a good recommendation of just how much water should be consumed on a daily basis. 

            It is important to have a good balance of macronutrients.  Proteins, fats, and carbohydrates are considered to be macronutrients and it is important that the right amount is consumed.  Most diets consist of a combination of the three.  When I am trying to eat a balanced nutritional diet, I make sure that I include all three in every meal that I have.

            Protein’s primary function is to build and repair tissues and structures.  This is why it is so important to consume protein after a workout, especially strength training.  When muscle tissue is strained and broken down, protein is the nutrient that builds and repairs it back up.  Protein is broken down into amino acids that the body uses to build or repair tissue or used as an energy source when calories or carbohydrates are insufficient to do so.  Some examples of proteins sources that I like are chicken, lean steaks, cottage cheese, or string cheese.

            Lipids, or fats, are the most concentrated source of energy.  Fats act as a carrier for fat-soluble vitamins A, D, E, and K.  In addition, fats are responsible for the regulation and excretion of nutrients in cells, protecting and holding in place organs, insulating the body, and helping to create sensation of fullness after a meal.  The recommended range for fat intake is 20 to 25% of total calories from fat (Nettleton, 2013).  Eating more than what is recommended can lead to a slower metabolism.  One of my favorite ways to get good, healthy fats into my diet is to consume avocados.  They are higher in calories, but packed with the right kind of fats that will help you get the healthy fats that a body needs. 
Carbohydrates are the main source of readily available energy for body function and muscular exertion.  Carbohydrates help to utilize fat and protein, in addition to regulating the digestion system.  Carbohydrates make glucose, which is the fuel that gives the body energy and helps keep everything going (Neacsu, 2014).  Recommended intake for carbohydrate is 45 to 65% of caloric intake.  Some of my favorite healthy carbohydrates to eat are whole wheat bread and fruits. 

      
     
There is a process to the digestion, absorption, and metabolism of these macronutrients.  I will use the example of a cheeseburger to describe what happens when all three macronutrients are digested in the body.  First, a bite is taken out of the cheeseburger.  The mouth chews up the bite so that it is easier to pass down the esophagus.  This also makes the cheeseburger easier to digest.  The food is mixed with saliva and the enzyme in saliva provides the ability to break down starch and has a trace of a fat-digesting enzyme that infants need.   The enzymes in the saliva also to break down the food into a mass called a bolus, which is then ready to be swallowed.  The tongue moves the food to the back of the mouth and then after the bolus is swallowed, it makes its way down the esophagus and into the stomach. 

            The stomach is where the chewed up cheeseburger, or bolus at this point, hangs out for a while and is churned, mashed, and mixed into a fine paste, thanks to the stomach muscle layers.  Gastric juice is a mix of water, enzymes, and hydrochloric acid.  The acid is needed to activate a protein-digesting enzyme so that the protein can be digested.  In the case of the cheeseburger, the protein from the meat and cheese in the cheeseburger needs to be broken down and the hydrochloric acid is what allows the protein to be used for muscle building.  Digestion of starch continues to occur while in the upper stomach.  Stomach acid is so strong that it can actually give you a chemical-like burn on your hand. Fat from the cheese and meat is last to leave stomach and floats on top of fluid mixture.  Mucus in the stomach allows the stomachs lining to be protected from the acid. The stomach uses water and digestive chemicals to turn the paste into a thick liquid mass called chyme.  At this point, the cheeseburger does not look like a cheeseburger anymore.  The chyme is then slowly squirted a little at a time into the small intestine.

            The small intestine is very active in the digestion process.  This is where other organs help out with the digestion process.  The gallbladder squirts bile into the intestine in order to emulsify fat and oils.  The pancreas releases pancreatic juice that neutralizes the stomach acid that has hit the small intestine.  The walls of the intestine also have digestive enzymes that help in the digestive breakdown so that even more nutrients can be absorbed and used.  Most of the carbohydrates, fat, and proteins are completely absorbed by the time contents enter the colon (Sizer & Whitney, 2013). The liver acts as an accessory and helps to produce bile that helps digest the fats. 

            In the colon or large intestine, intestinal bacteria helps break down some of the undigested carbohydrates.  Fiber and some fatty materials get excreted.  Most protein is digested, but whatever is left will be carried out by the large intestine.  Any leftover water and minerals are reabsorbed here also.   At this point, most of the digestion and absorption of the cheeseburger is complete.  The colon absorbs most of the water that used to help digestion and mineral absorption.  What is left of the cheeseburger is a paste of fiber and other undigested materials called feces.  The feces are then excreted through the anus.
Braintofu (2014). Image retrieved from http://i.ytimg.com/vi/0eAI7kmiryQ/hqdefault.jpg
Haiku deck (2015). Life of a cheeseburger. Image retrieved from https://www.haikudeck.com/life-of-a-cheeseburger-uncategorized-presentation-bsUGxket54
 
Neacsu, N. A. (2014). EFFECTS OF CARBOHYDRATE CONSUMPTION. CASE STUDY: CARBOHYDRATES IN BREAD. Bulletin of the Transilvania University of Brasov.Economic Sciences.Series V, 7(2), 39-44. Retrieved from http://search.proquest.com/docview/1658463257?accountid=32521

Nettleton, J. A., Villalpando, S., Cassani, R. S. L., & Elmadfa, I. (2013). Health significance of fat quality in the diet. Annals of Nutrition & Metabolism, 63(1-2), 96-102. doi:http://dx.doi.org/10.1159/000353207

Sizer, F. & Whitney, E. (2013).  Nutrition: Concepts and Controversies (13th ed.).  Mason, OH:   Cengage Learning.
Water is one of the body's essential nutrients for good health. (2004, Jul 26). Daily Breeze Retrieved from http://search.proquest.com/docview/338671459?accountid=32521

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