Human nutrition or the process of the taking in and absorbing of nutrients is what we are concerned with discussing here. There us an oft quoted maxim that "you are what you eat". It is probably important to add to this that we are what we eat and drink.
Nutrition is an extremely important facet of overall health in human beings. It is very often only seriously looked at in the realms of medicine and in sporting enhancement. However the importance of good if not excellent human nutrition should not be overlooked for individuals who either do not participate in sporting activities or who are currently of good health.
Why nutrition is important
At the expense of stating the obvious nutrition is important because it provides our bodies with all of the individual entities it requires for life and to maintain what is know as the status quo.
All over the world different peoples and different races have developed and evolved to enjoy an enormous variety of different food substances. Essentially however our bodies require certain substances to maintain a healthy existence.
The Essentials of Human Nutrition
The essential requirements for a healthy living organism are:
* Carbohydrates mainly for energy purposes.
* Protein for building and replenishing structures.
* Fat as an important energy resource and for the facilitation of essential body processes.
* vitamins and minerals.
The Digestion Process
The human nutrition assimilation process begins with the intake of food or drink into the mouth. It is at this point that the ingestion of nutrients actually begins.
Salivary amylase is a substance secreted from glands within the mouth to begin the breakdown of large carbohydrate molecules known as starch. The mechanical breakdown via the action of chewing reduces the food substance into more manageable quantities and the food once chewed is formed into a small ball know as a bolus. The bolus of food then passes down the oesophagus via smooth muscle action and enters the stomach.
Once in the stomach digestion continues further with the secretion from glands within the stomach of gastric acid and other digestive enzymes which are responsible for the breakdown of protiens and fat. Only some small molecules are absorbed by the stomach into the blood stream. The most commonly known one being alcohol which is the reason for its rapid action in terms of the time it takes from ingestion to produce its effects.
The food will stay in the stomach for a length of time depending upon the nature of the food substance. If there is a high fat or protein content to the food then there will be more breakdown required and hence the food will stay in the stomach for a longer period of time.
Simple foods, for example fruits, pass through the stomach and the rest of the digestive tract fairly quicky because they require energy to breakdown.
The Small Intestine and Liver
The food then passes from the stomach into what is know as the small intestine or ilium. It is here that the majority of nutrient absorption occurs. The interior wall of the ilium has an enlarged surface area with many projections known as villi involved to allow maximum absorbtion. The minute nutrients are then carried away from the blood stream. The nutrients are filtered via the liver for removal of toxins before being utilised.
The Large Intestine
Food substances that are not absorbed via the small intestine are transported via peristaltic or smooth muscle movement into the large intestion known as the colon. It is in the colon that fluid or water is absorbed into the body. Any substances that pass through the colon and are not required will pass throught as waste products to be excreted.
Find out about the specifics of human nutrition in sport