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 RequirementsCategory CaloriesTeen males, many active men, and some very active women. 2,800

Older children, teen females, active women, and most emn. Women who are pregnant or breast-feeding may need more. 2,200

Younger children, women, and most older adults 1,600

Recommended Calorie AmountsNutrient Calories1 g pure Carbohydrate 4 Calories1 g Pure Protein 4 Calories1 g Pure Fat 9 Calories

Calories in NutrientsNutrient Teens AdultsCarbohydrate 45-65% 45-65%Proteins 10-30% 10-35%Fats 25-35% 20-35%

Nutrient Sources for Calories

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.