The body can manufacture all of the fatty acids it needs except for the essential fatty acids (efas). There are two efas: linoleic acid and linolenic acid. (The preceding example was a representation of linolenic acid.) Since the body cannot manufacture efas, they must be obtained from the diet.
Both EFAS are precursors to prostaglandins. By varying the ratio of EFAS, it is possible to manipulate prostaglandin synthesis.
Young children need more EFAS than adults, and males need more than females. Children under two years that are fed low fat cows’ milk can develop an EFA deficiency.
Types of Lipids
How are fatty acids related to the everyday fats and oils we are familiar with? In general, they combine to form lipids (fats) in food.
Most of the lipids in foods are triglycerides, combinations of four molecules: the glycerol molecule, which acts as a three âœrodâ hanger, and the three fatty acids that hang from each âœrod.â The properties and abilities of each triglyceride depend upon the characteristics of its component fatty acids.
For example, the properties of an oil are related to the types of triglycerides found in that oil. In turn, the properties of triglycerides are determined by the fatty acids that form it, and the properties of the fatty acids are determined by their structure. The longer and more unsaturated the fatty acids, the more liquid or soft the fat is at room temperature. The order of the fatty acids on the glycerol molecule also affect the digestibility and absorbability of the triglyceride. Because so many different fatty acids are present in natural foods, many types of triglycerides are found in a fat or oil.
Besides triglycerides, foods also contain monoglycerides (with one fatty acid hanging on the glycerol) and diglycerides (with two fatty acid molecules). These molecules are also produced during the digestion of triglycerides.