Final answer:
Humans cannot synthesize essential fatty acids, specifically linoleic acid (omega-6) and alpha-linolenic acid (omega-3), and must obtain them through their diet. Foods like plant oils, nuts, flaxseeds, and leafy vegetables are rich in these fatty acids, and intake of 4 to 6 grams per day is recommended for health maintenance.
Step-by-step explanation:
The type of fatty acids that humans are unable to synthesize are called essential fatty acids. Essential fatty acids are vital nutrients that our bodies require but cannot create on their own. The two essential fatty acids for humans are linoleic acid (an omega-6 fatty acid) and alpha-linolenic acid (ALA, an omega-3 fatty acid).
These polyunsaturated fatty acids must be obtained through our diets. Linoleic acid is used by the body to synthesize many other unsaturated fatty acids, such as arachidonic acid, which is a precursor for the synthesis of prostaglandins, crucial for various bodily functions. Similarly, alpha-linolenic acid can be converted into other important omega-3 fatty acids, although the conversion rate is low, meaning direct dietary sources of omega-3s like EPA and DHA are also recommended.
Examples of foods rich in linoleic acid include plant oils like corn oil and soybean oil, while alpha-linolenic acid can be found in nuts, flaxseeds, whole grains, legumes, and dark green leafy vegetables. The average daily diet should contain about 4 to 6 grams of essential fatty acids to maintain proper health and support growth and development.