Fat has been loosely and interchangeably described as lipids. The descriptions were attempts to distinguish fat from other nutrients based on it solubility in nonpolar solvent.
Currently, fat refers to triglycerides in the United States but total lipids in the European Community.
Fats are comprised of fatty acids bound, in bundles of three, to glycerol. There are three major types of fats or fatty acid:
*Saturated
*Monounsaturated
*Polyunsaturated
Saturated fats are solid at room temperature and have no room for any additional hydrogen atoms. It is primarily found in animal foods.
Mono and polyunsaturated fats, which remain liquid at room temperature, have room for additional hydrogen atoms.
Fats contains mixtures of all three types of fatty acids; the balance of the mix determines whether the fat is generally saturated (hard) or polyunsaturated (soft).
Fats are insoluble in water and require special treatment for digestion and transport. In digestion, bile acids act as detergents to solubilize fats to aids digestion.
In transport, the fatty material is surrounded by a coat of protein plus phospholipid. The full particle is a lipoprotein.
The liver can convert carbohydrate to fat, which is exported from the liver as a lipoprotein.
Fats are an important energy source in human nutrition. Besides the high energy content, many fats and oils contain fatty acids that are essential to health and cannot be synthesized by the human body.
Certain polyunsaturated fatty acids are nutritionally essentially because:
1. They are the precursors of the vitality important regulators of metabolism, the prostaglandins
2. The body cannot make them from either carbohydrate or existing dietary fatty acids.
The fat content of foods can range from very low to very high in both vegetable and animal products.
Fats are sometimes divided into visible and invisible fats.
In the United States, about 60 percent of total fat and oil consumed consists of invisible fats – that is, those contained in dairy products – eggs, meat, poultry, fish, fruits, vegetables and grain.
The visible fats, including lard, butter, margarine, shortening and cooking oils, account for 40 percent of total fat intake.
Definition and summary of fats
