Chapter 18
Nutrition
Courtesy of United States Department of Agriculture
Nutrients are substances in foods that provide energy and materials for cell development, growth, and repair.
Our body needs energy which we get from the food we eat. This energy is measured in Calories. A Calorie is the amount of heat necessary to raise the temperature of 1 kg of water 1 degree Celsius. For example, a taco may have 180 Calories. This means your body has 180 Calories of energy to use.
There are six classes of nutrients found in food: proteins, carbohydrates, fats, vitamins, minerals, and water.
Proteins are large molecules made of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. They provide long term energy and build and repair body cells. Meats, fish eggs, nuts, and legumes are significant sources of protein. Proteins release 4 Cal/gram as energy. The building blocks for proteins are amino acids.
There are twenty amino acids your body needs to make different proteins. The amino acids your body cannot make are essential amino acids which need to be supplied by your foods. Eight amino acids are essential plus two more for children. Complete proteins have all essential amino acids and are found in animal products. Incomplete proteins are missing one or more of the essential amino acids. Plants are incomplete proteins.
Carbohydrates are made of carbon, hydrogen, and oxygen. They are the main source of energy for your body and can be used as quick energy. Grains, fruits, vegetables, and dairy products are significant sources of carbohydrates. Carbs release 4 Cal/gram as energy. The building blocks of carbohydrates are simple sugars.
Fats, or lipids, are made of carbon, hydrogen, oxygen, nitrogen, and potassium. They cushion internal organs and absorb fat soluble vitamins. Fats, oils, and sweets are significant sources of fat. Fats release 9 Cal/gram as energy. Glycerols and fatty acids are the building blocks of fats.
Vitamins are organic nutrients needed in small quantities for growth, regulation of body functions, and prevention of some diseases. Vitamins release 0 Cal/gram as energy.
There are two classes of vitamins: fat soluble and water soluble. Fat soluble vitamins only dissolve in fat and are stored in the body. Water soluble vitamins dissolve easily in water and need to be replenished daily because they aren't stored in the body. Vitamins B and K are water soluble, and vitamins D, E, K, and A are fat soluble.
Minerals are inorganic nutrients (nutrients that lack carbon). They regulate chemical reactions, send nerve impulses throughout your body, and carry oxygen to body cells. Minerals release 0 Cal/gram as energy. There are fourteen minerals that our body uses to function.
Water is made of two hydrogen atoms bonded to one oxygen atom. It is the second most important factor for survival besides oxygen. This is why we are made up of about sixty percent water. Most chemical reactions in the body occur in water solutions, and water is needed to bring nutrients to cells.
We need to eat a balanced diet in order to get all the nutrients we need for our body to function. That is why we have a food pyramid. The food pyramid is split up into six different food groups: grains, vegetables, fruits, milk, meat and beans, and oils. Foods that contain the same type of nutrient belong to a food group. Depending on your age, size, and activity level, you will need to eat a certain number of servings from each food group each day.
Our body needs energy which we get from the food we eat. This energy is measured in Calories. A Calorie is the amount of heat necessary to raise the temperature of 1 kg of water 1 degree Celsius. For example, a taco may have 180 Calories. This means your body has 180 Calories of energy to use.
There are six classes of nutrients found in food: proteins, carbohydrates, fats, vitamins, minerals, and water.
Proteins are large molecules made of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. They provide long term energy and build and repair body cells. Meats, fish eggs, nuts, and legumes are significant sources of protein. Proteins release 4 Cal/gram as energy. The building blocks for proteins are amino acids.
There are twenty amino acids your body needs to make different proteins. The amino acids your body cannot make are essential amino acids which need to be supplied by your foods. Eight amino acids are essential plus two more for children. Complete proteins have all essential amino acids and are found in animal products. Incomplete proteins are missing one or more of the essential amino acids. Plants are incomplete proteins.
Carbohydrates are made of carbon, hydrogen, and oxygen. They are the main source of energy for your body and can be used as quick energy. Grains, fruits, vegetables, and dairy products are significant sources of carbohydrates. Carbs release 4 Cal/gram as energy. The building blocks of carbohydrates are simple sugars.
Fats, or lipids, are made of carbon, hydrogen, oxygen, nitrogen, and potassium. They cushion internal organs and absorb fat soluble vitamins. Fats, oils, and sweets are significant sources of fat. Fats release 9 Cal/gram as energy. Glycerols and fatty acids are the building blocks of fats.
Vitamins are organic nutrients needed in small quantities for growth, regulation of body functions, and prevention of some diseases. Vitamins release 0 Cal/gram as energy.
There are two classes of vitamins: fat soluble and water soluble. Fat soluble vitamins only dissolve in fat and are stored in the body. Water soluble vitamins dissolve easily in water and need to be replenished daily because they aren't stored in the body. Vitamins B and K are water soluble, and vitamins D, E, K, and A are fat soluble.
Minerals are inorganic nutrients (nutrients that lack carbon). They regulate chemical reactions, send nerve impulses throughout your body, and carry oxygen to body cells. Minerals release 0 Cal/gram as energy. There are fourteen minerals that our body uses to function.
Water is made of two hydrogen atoms bonded to one oxygen atom. It is the second most important factor for survival besides oxygen. This is why we are made up of about sixty percent water. Most chemical reactions in the body occur in water solutions, and water is needed to bring nutrients to cells.
We need to eat a balanced diet in order to get all the nutrients we need for our body to function. That is why we have a food pyramid. The food pyramid is split up into six different food groups: grains, vegetables, fruits, milk, meat and beans, and oils. Foods that contain the same type of nutrient belong to a food group. Depending on your age, size, and activity level, you will need to eat a certain number of servings from each food group each day.
The Digestive System
Courtesy of Web Books
In our body, food goes through four different stages: ingestion, digestion, absorption, and elimination. Digestion is the process that breaks down food into small molecules so that they can be absorbed and moved into the blood. There are two types of digestion: mechanical and chemical. Mechanical digestion occurs when food is chewed, mixed, and churned. Chemical digestion occurs when chemical reactions break down large food molecules into smaller molecules.
An enzyme is a type of protein that speeds up chemical reactions. Enzymes are needed in order for chemical digestion to take place. In digestion, enzymes break down large molecules into small molecules so they can be absorbed and used in the body. Enzymes have certain steps to break down carbs, proteins, and fats:
Carbs: Starches ==> Complex Sugars ==> Simple sugars
Proteins: Polypeptides (large proteins) ==> Peptide chains (small proteins) ==> Amino Acids
Fats: Large Fats ==> Small Fats ==> Glycerols and Fatty Acids
There are many different enzymes needed in order for digestion to occur:
Made in the salivary glands: Ptyalin- breaks down starches into complex sugars
Made in the stomach: Pepsin- breaks down polypeptides into peptide chains
Made in the liver (stored in the gallbladder): Bile- breaks down large fats into small fats
Made in the pancreas: Amylase- breaks down starches into complex sugars
Trypsin- breaks down polypeptides into peptide chains
Lipidase- breaks down small fats into glycerols and fatty acids
Made in the duodenum: Sucrase, Maltase, Lactase- breaks down complex sugars into simple sugars
Peptidase- breaks down peptide chains into amino acids
Lipidase- breaks down small fats into glycerols and fatty acids
Enzymes are also used for other actions in the body like producing energy for muscle and nerve cells and aiding in blood clotting. Without enzymes, chemical reactions would occur more slowly and some wouldn't occur at all. So, without enzymes, we would die.
The digestive system has two parts: the digestive tract and the accessory organs. Accessory organs, or digestive helpers, are the liver, gallbladder, and pancreas. These organs do not have food pass through them but are needed in order for your digestive system to run properly.
The digestive tract is as follows:
Mouth- Mechanical (MD) and Chemical (CD) digestion
Teeth: mash up food (MD)
Tongue: mixes up food (MD)
Saliva: moistens food (MD) and contains ptyalin that breaks down starches into complex sugars
Pharynx- (MD)
Esophagus- uses waves of muscle contractions called peristalsis to move food into the stomach (Route)
Stomach- peristalsis still occurs (MD), and the enzyme pepsin breaks down polypeptides into peptide chains (CD)
digested food turns into a thin, watery liquid called chyme
Small Intestine- many different enzymes break down proteins, carbs, ad fats here (CD)
contains villi, finger-like projections on the wall of the small intestine that increase its surface area and
absorb nutrients from chyme so that they can be brought throughout the body by the blood
Large Intestine- absorbs water from the chyme to maintain homeostasis and turns chyme into a semisolid waste (Route)
bacteria feed on undigested chyme to make Vitamins B and K
Rectum- controls release of semisolid waste, or feces (Route)
Anus- sphincter muscle; releases feces (Route)
An enzyme is a type of protein that speeds up chemical reactions. Enzymes are needed in order for chemical digestion to take place. In digestion, enzymes break down large molecules into small molecules so they can be absorbed and used in the body. Enzymes have certain steps to break down carbs, proteins, and fats:
Carbs: Starches ==> Complex Sugars ==> Simple sugars
Proteins: Polypeptides (large proteins) ==> Peptide chains (small proteins) ==> Amino Acids
Fats: Large Fats ==> Small Fats ==> Glycerols and Fatty Acids
There are many different enzymes needed in order for digestion to occur:
Made in the salivary glands: Ptyalin- breaks down starches into complex sugars
Made in the stomach: Pepsin- breaks down polypeptides into peptide chains
Made in the liver (stored in the gallbladder): Bile- breaks down large fats into small fats
Made in the pancreas: Amylase- breaks down starches into complex sugars
Trypsin- breaks down polypeptides into peptide chains
Lipidase- breaks down small fats into glycerols and fatty acids
Made in the duodenum: Sucrase, Maltase, Lactase- breaks down complex sugars into simple sugars
Peptidase- breaks down peptide chains into amino acids
Lipidase- breaks down small fats into glycerols and fatty acids
Enzymes are also used for other actions in the body like producing energy for muscle and nerve cells and aiding in blood clotting. Without enzymes, chemical reactions would occur more slowly and some wouldn't occur at all. So, without enzymes, we would die.
The digestive system has two parts: the digestive tract and the accessory organs. Accessory organs, or digestive helpers, are the liver, gallbladder, and pancreas. These organs do not have food pass through them but are needed in order for your digestive system to run properly.
The digestive tract is as follows:
Mouth- Mechanical (MD) and Chemical (CD) digestion
Teeth: mash up food (MD)
Tongue: mixes up food (MD)
Saliva: moistens food (MD) and contains ptyalin that breaks down starches into complex sugars
Pharynx- (MD)
Esophagus- uses waves of muscle contractions called peristalsis to move food into the stomach (Route)
Stomach- peristalsis still occurs (MD), and the enzyme pepsin breaks down polypeptides into peptide chains (CD)
digested food turns into a thin, watery liquid called chyme
Small Intestine- many different enzymes break down proteins, carbs, ad fats here (CD)
contains villi, finger-like projections on the wall of the small intestine that increase its surface area and
absorb nutrients from chyme so that they can be brought throughout the body by the blood
Large Intestine- absorbs water from the chyme to maintain homeostasis and turns chyme into a semisolid waste (Route)
bacteria feed on undigested chyme to make Vitamins B and K
Rectum- controls release of semisolid waste, or feces (Route)
Anus- sphincter muscle; releases feces (Route)
Courtesy of The Aquino Clan
