CHAPTER 3

Health, Nutrients, and DigestionRiley Kelfer B Block

Ch. 3-1 Overview

In food, the substances that provide energy and raw materials for the body’s use are called nutrients.

Without them, the body would not be able to carry out its essential functions and processes.

The 6 types of nutrients are carbohydrates, lipids, proteins, vitamins, minerals, and of course- water.

The amount of energy released by nutrients when used by the body is measured by calories.

Ch. 3-1 Carbohydrates

Hydrogen, oxygen, and carbon are the elemental constituents of carbohydrates.

All carbs provide energy and materials to the body, but because their chemical makeup may differ, they are ÷.

Complex carbs include starches and fibers, and are made of many sugar molecules linked in a chain.

Simple carbs such as the natural glucose and sugar substitutes like maltodextrin provide quick energy.

Ch. 3-1 Lipids

Lipids usually contain about twice the amount of energy as carbohydrates and are also made of C H O.

Fat tissue from lipids play an important role in protecting the body’s internal organs from injury.

One type of fat is unsaturated fat, and it includes mostly liquids like olive and canola oil.

Another type of fat is saturated fat, which includes mainly animal and dairy products as well as some oils.

Ch. 3-1 Proteins

Comprised of carbon, hydrogen, oxygen, and nitrogen, proteins help carry out various processes in the body.

Some examples of protein-rich foods are fish, meats, nuts, legumes, and dairy products.

Amino acids are the smalls structures that make up proteins. Some acids are necessary, while some aren’t.

Our body can only produce ≈half of the 20 amino acids, so we must get the others from foods.

Ch. 3-1 Vitamins

Vitamins come in many forms and provide various specialized functions within the body.

Vitamins are important in aiding chemical reactions that take place in the body.

Vitamins also come in many different forms- in fruit, vegetables, meats, eggs, dairy et cetera.

Although the body does not need much of a single nutrient, it is important to get some from each of them.

Ch. 3-1 Minerals

Some minerals that are essential to the body’s functions are calcium, potassium, sodium and so forth.

Minerals are not made by living things, but rather by the soil and earth.

In order to get these minerals, one has to eat plants that absorb the minerals along with water through roots.

Each mineral performs a specific job, so just like vitamins, the body needs a bit of all of them.

Ch. 3-1 Water

Water is the most copious substance in the body. It aids in chemical reactions and many other functions.

The breakdown of nutrients and and the body’s vital functions take place in water.

The body’s fluids, such as blood and lymph also contain a vast majority of water.

In addition, the other nutrients are dissolved in water making it very important in staying healthy.

Ch. 3-2 Overview

The Food Pyramid includes 6 categories of food; their size representing how much you should eat each day.

A healthy diet includes all the categories of the food pyramid with an emphasis of fruits, vegetables, and grains.

It is also important to read food labels so that you can be aware of your calorie intake. This also applies to excessive amounts of sugar and polyunsaturated fats.

Ch. 3-2 Food pyramid

One should eat the most amount of grains such as pasta to provide energy.

Although it is important to limit the intake of foods from the meats group, as they are high in fats.

Fruits and vegetable often have many vitamins and minerals in them, but fruits also have lots of sugar.

Instead of focusing on one food group, it is important to eat a varied diet across the groups.

Ch. 3-2 Food labels

Food labels are a way to look at the nutritional facts for a certain food.

In addition, one can compare two products using their individual nutrition facts.

When observing the ‘ingredients’ section, the first ingredient listed is the most abundant in the product.

A good rule of thumb for ingredients is: if you can’t pronounce it, it is probably not very healthy.

Ch. 3-3/Ch. 3-4 Overview

Function: It breaks down food into smaller molecules usable by the body.

Function2: Molecules are absorbed into the blood in the process of absorption in the small intestine.

Function3: Unusable wastes are eliminated from the body.

Food flows throughout each of the organs of the digestion system in peristalsis.

Ch. 3-3 The Mouth

All foods starts its journey through the digestive system in the mouth.

Different types of teeth help to mash up and tear food into manageable sizes.

Mastication is an example of mechanical (or physical) digestion.

Salivary glands secrete enzymes which break down food through chemical digestion.

Ch. 3-3 The Esophagus

After the tongue and palate roll the food into ball-shaped structure called a bolus, the esophagus pushes the food down through waves of muscle contractions called peristalsis.

The pharynx is where the nasal cavity and the back of the mouth meet in the esophagus.

The epiglottis is the flap of skin in the esophagus that keeps food from going into the trachea.

Ch. 3-3 The Stomach

The food that has been moved through the esophagus now lands in the stomach.

The stomachs physical churning of the food is a type of mechanical digestion.

Likewise, the various chemicals that engulf the food are an example of chemical digestion.

Without the thick lining of mucus on the inside of the stomach, the chemicals could digest the stomach itself!

Ch. 3-4 Small Intestine

The small intestine is where virtually all chemical digestion and absorption takes place.

The wall of the small intestine is lined with certain folds called villi that aid in absorption.

The small intestine is extremely long, strangely much longer than the large intestine.

Broken down molecules from food are absorbed through the walls of the intestine.

Ch. 3-4 Pancreas, Liver, Gallbladder

The liver is the largest and heaviest internal organ. It produces bile, a certain chemical compound that aids in the digestion of fat.

The gallbladder is the smaller organ underneath the liver that stores extra bile until it is needed.

The pancreas secretes special enzymes that aid in digestion. All these organs work together to help the process of digestion move more smoothly.

Ch. 3-4 Large Intestine

The large intestines main purpose is to eliminate excess water from undigested materials

Fiber, found in many types of fruits, is an example of one such material.

The large intestine readies these materials for elimination through the excretory system.

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