NUTRIENTS AT WORK Chapter 5

Objective ◦ Explain the impact of nutrients on your body and health. ◦ Describe standards and guidelines that provide information about nutrient requirements. ◦ Summarize the steps in the digestive process. ◦ Explain how nutrients are absorbed, transported, and stored in the body. ◦ Discuss the role of metabolism in the body.

Terms ◦Absorption ◦Adequate intakes (AI) ◦Anemia ◦Basal Metabolism ◦Calorie ◦Chyme ◦Dietary Reference Intakes (DRI) ◦Digestion ◦Enzyme ◦Esophagus ◦Glucose ◦Glycogen ◦Malnutrition ◦Metabolism ◦Oxidation ◦Pancreas ◦Peristalsis ◦Recommended Dietary Allowances (RDA) ◦Villi

6 Basic Nutrients and Their Functions ◦ Carbohydrates – Provide the body’s main source of energy. ◦ Fats – Provide a concentrated source of stored energy as well as insulation for the body. ◦ Proteins – Help build, repair, and maintain body tissues. ◦ Vitamins – Help regulate many vital processes. ◦ Minerals – Help the body work properly. ◦ Water – Participates in chemical reaction in the body and helps transport materials to and from cells.

Nutrients and Health ◦Malnutrition – a deficiency or severe shortage of a nutrient, or having too much of a nutrient from overeating. ◦Anemia – not getting the recommended amount of iron. ◦Having a healthy lifestyle helps with: ◦Appearance ◦Fitness ◦Weight ◦Illness ◦Healing ◦Emotions ◦Future Health

Digestion ◦Digestion – is the mechanical and chemical process that breaks food down to release nutrients in forms your body can absorb. ◦Parts of the digestive system: ◦Mouth ◦Salivary Glands ◦Esophagus ◦Stomach ◦Liver ◦Pancreas ◦Small Intestine ◦Large Intestine

The Mouth ◦ Digestion begins by chewing food to the consistency of applesauce. ◦ Saliva is released in the mouth containing enzymes that help to break down food. ◦ The sight and smell of food helps to release the saliva and gets your mouth “watering” ◦ Taste buds on the tongue can identify four general flavors: ◦ Salty ◦ Bitter ◦ Sour ◦ Sweet

The Esophagus ◦ Connects the mouth to the stomach. ◦ Once food is chewed it passes into the esophagus. ◦ Food moves through the esophagus by peristalsis to the stomach

The Stomach ◦ Hollow, muscular pouch at the end of the esophagus, below the rib cage. ◦ Widest part of the digestive system, and can hold about 6 cups of food. ◦ Produces gastric juices (acids and enzymes) that helps food break down chemically. ◦ Also breaks down food mechanically through peristalsis. ◦ Turns food into a thick liquid called chyme.

The Small Intestines ◦ Attached to the stomach. Food passes from the stomach to the small intestines. ◦ Three types of digestive juices act on the chyme as the breakdown of carbohydrates, proteins, and fats continues. ◦ Bile – Helps the body digest and absorb fats. Bile is produced in the liver and stored in the gall bladder. ◦ Pancreatic juice – contains enzymes that help break down carbohydrates, proteins, and fats. The Pancreas produces this substance. ◦ Intestinal juice – works with other juices to break down food. It is produced in the small intestine.

Absorption of Nutrients ◦ Once food is broken down it must be absorbed into the bloodstream. ◦ This takes place through the surface of the small intestine. ◦ Villi (billions of tiny, fingerlike projections) increase the surface area of the intestine so that more nutrients can be absorbed. ◦ After absorption, waste material is moved into the large intestine.

Nutrient Transportation ◦ After nutrients are absorbed they are transported to the liver to be turned into forms that the body can use. ◦ Carbohydrates are broken down into glucose a simple sugar that is the body’s basic fuel. ◦ Fats are broken down into fatty acids. ◦ Proteins are broken down into amino acids. ◦ Vitamins, minerals, and water are not broken down. ◦ After any necessary breakdown, nutrients are ready to be transported in the bloodstream to individual cells.

Nutrient Storage ◦ If not immediately needed, some nutrients are stored for further use. ◦ Liver turns glucose into glycogen, the extra is turned into fat. ◦ Fatty acids and amino acids are converted into body fat and deposited throughout the body. ◦ Minerals and vitamins are stored in various ways. ◦ Vitamins that are dissolved in fat are stored in the liver. ◦ Vitamins that are dissolved in water are removed from the body.

Metabolism ◦ Metabolism – living cells use nutrients in many chemical reactions that provide energy for vital processes and activities. ◦ Oxidation – glucose in the cells combine chemically with oxygen to produce energy and heat. ◦ Calorie – amount of energy needed to raise the temperature of 1 kilogram of water 1 degree Celsius.

Recommended Requirements

Metabolism ◦ Basal metabolism – the minimum amount of energy you need to maintain basic functions. ◦ Energy requirements – the number of calories you need for energy on a given day. Age, weight, gender, and activity level do impact what you need.