Final answer:
Omega-3 and omega-6 fatty acids are the essential fatty acids humans need to include in their diet to avoid deficiency, as they are not synthesized by the body. These fatty acids are required for normal body function, growth, and development. Foods like nuts, seeds, plant oils, and green leafy vegetables are good sources.
Step-by-step explanation:
The essential fatty acids that must be provided in the diet to avoid deficiency are omega-3 and omega-6 fatty acids. These are the only two known essential fatty acids for humans, which the body cannot synthesize and must be ingested through food. Omega-3 fatty acids, like alpha-linolenic acid (ALA), are critical as they play a role in the normal functioning of all body systems including growth, development, and efficient transport and metabolism of cholesterol. Foods rich in omega-3 include nuts, flaxseed, and dark green leafy vegetables. Linoleic acid, an omega-6 fatty acid, is also vital; it is used to synthesize other fatty acids, such as arachidonic acid, and is typically found in plant oils like corn and soybean oil.
The body needs about 4-6 grams of essential fatty acids daily, which must come from dietary sources as they are not synthesized by the human body. Despite their name, 'nonessential fatty acids' are still important for health; the term 'nonessential' only refers to the body's ability to synthesize them.