Fat
Objective
- Identify the classification of fat
- Fat function
- Digestion, absorption and metabolism
- Identify food sources of fat
Saturated fats
Saturation of fatty acids depends on how many hydrogen atoms bond to the four potential bonding sites of each carbon atom. If all four sites have a hydrogen atom bond, it s saturated. Because all of the carbon atoms are bonded to as many hydrogen atoms as they can hold, no double bonds between carbon atoms exist.
Saturated fats are found in meat, poultry, full-fat dairy products, and tropical oils, such as palm and coconut oils. Most saturated fats:
* less likely to become rancid.
* originate from animal sources
* remain solid at room temperature
* have high melting points
Unsaturated Fats
In general, un saturated fats has double bonds between carbon atoms.
* originate from plant
* fat and oils are soft or liquid at room temperature
* have lower melting points than saturated fats
can become rancid when exposed to extended
periods of light and oxygen.
There are two types of unsaturated fatty acids mono unsaturated (MUFA) and polyunsaturated (PUFA). MUFA are found mostly in vegetable oils, such as olive, canola, and as sunflower, safflower, and soybean oils and in peanut oils.
Fats perform six general functions in the body:
*providing energy for the body
* facilitating absorption of fat-soluble vitamins supplying essential fatty acids
* supporting and protecting internal organs aiding in temperature regulation lubricating body tissue.
* Fat is a concentrated form of energy that provides 9 cal/g double the amount of calories of either a carbohydrate or protein.
* Yet fat isn t the body s preferred fuel sourcing because it s more difficult to metabolize.
* Stored fat in adipose cells represents the body s largest and most efficient energy reserve. Adipose cells have a virtually limitless capacity to store fat.
Essential fatty acids
Dietary fat supplies the essential fatty acids: linoleic acid and alpha-linolenic acid. These are considered essential fatty acids because the body can t manufacture them.
Essential fatty acids are important for:
- maintaining healthy skin,
- promoting normal growth in children,
- maintaining healthy immune function.
- They may also play a role in the prevention of age-related chronic diseases, such as heart disease and Alzheimer s disease.
- Fatty tissue cushions and protects vital organs by providing a supportive fat pad that absorbs mechanical shocks. Examples of organs supported by fat are the eyes and kidneys.
- Fat layers insulate the skin, helping to protect the body from excessive heat or cold.
- A sheath of fatty tissue surrounding nerve fibers provides insulation to help transmit nerve impulses.
- Fats also lubricate the body tissue. The human body manufactures oil in structures called sebaceous glands. Secretions from sebaceous glands lubricate the skin to slow the loss of body water to the outside environment.
Sources of fat
The type and amount of fat in each food group vary. Some fat is visible, such as butter and the fat surrounding a piece of steak. However, most fat is invisible, such as the fat in milk, cheese, and nuts and the fat that s intertwined in the steak. Animal sources account for approximately 57% of total fat intake; plant sources account for the rest.
The saturated fat in the diet of an American adult are:
Beef, butter or margarine
Vegetable and fruit groups
With the exception of avocado, coconut, and olives, fruits don t contain appreciable amounts of fat. Unadulterated vegetables contain little or no fat. Vegetables that are fried, creamed, served with cheese, or mixed with mayonnaise contain significantly more fat.
Milk group
Items within the milk group come in fat-free, reduced-fat, and whole-fat varieties. To reduce your patient s risk of high-fat intake among foods in this group, advise him to read labels and compare different varieties and brands. Because dairy foods originate from animals, also have him watch cholesterol levels in these products.