Nutrients are the substances in food that maintain the body and make it work. Most of what one eats is made up of carbohydrates, proteins, and fats. Nutrients needed in smaller amounts, but still vital, are vitamins and minerals. Also on the list are fiber and water. Our diet should comprise a mix of foods that supply all necessary nutrients in the right amounts. Such a diet is called a balanced diet. Let’s have a glimpse of nutrition in human beings.
Complex carbohydrates, particularly starch, are found in foods such as pasta, bread, rice potatoes, and cereals. During digestion, starch is broken down to the simple sugar glucose, the body’s main source of energy.
Vitamins and Minerals:
Only needed in tiny amounts, vitamins and minerals are nonetheless essential for growth and good health. Most vitamins come from fresh fruit and vegetables, with some also found in fish, meat, dairy, and eggs. Minerals, such as calcium and iron, also help the body perform optimally. The best sources are vegetables, dairy, meat, and some fish.
Dairy food, meat, seeds, and nuts all supply fats, as do vegetable oils. Fat is digested into fatty acids, which are used as an energy source and to make cell membranes. Or they are rebuilt into fat that, under the skin, insulates the body and helps to keep us warm.
Rich sources of proteins are fish, lean meat, poultry, and beans. Once digested, proteins supply the body with amino acids. These building blocks are reassembled by cells into different proteins used for construction such as enzymes, and a myriad of other roles.
Around 50 – 70 percent of our body is made of water. Therefore this amount should always be maintained in the body.
Digestion in Human Beings
Digestion in humans happens through a stepwise process which is common to all organisms. The order in which it occurs in human beings is described below
- Ingestion: It is the process of us ingesting the food by actually eating it. In the mouth the food material is subject to cutting, tearing, chewing, and a little bit of pre-digestion using the salivary juice and finally swallowing.
- Digestion: It is the breakdown of the ingested food into microscopic and finally molecular fragments. Most of the digestion happens in the stomach and a small part of it also occurs in the small intestine.
- Absorption: This is a critical stage where nutrients are taken up from digestive organs and distributed to the body’s tissues. This process is where food ingested is converted to actual energy to be used by our bodies.
- Excretion: This is the final process where waste material is excreted from our bodies.
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