Omega-3 fatty acids do not include which of the following fatty acids?

• A. Eicosapentaenoic acid (EPA, 20:5, \(\omega\)-3)
• B. Docosahexaenoic acid (DHA, 22:6, \(\omega\)-3)
• C. Alpha-linolenic acid (ALA, 18:3, \(\omega\)-3)
• D. Arachidonic acid (20:4, \(\omega\)-6)

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the classification of omega-3 fatty acids. Omega-3 fatty acids are a type of polyunsaturated fatty acid characterized by the presence of a double bond at the third carbon atom from the methyl end (denoted as \\(\omega-3\\)). Examples include Eicosapentaenoic acid (EPA), Docosahexaenoic acid (DHA), and Alpha-linolenic acid (ALA).
2. Step 2: Analyze the given fatty acids. Eicosapentaenoic acid (EPA, 20:5, \\(\omega-3\\)), Docosahexaenoic acid (DHA, 22:6, \\(\omega-3\\)), and Alpha-linolenic acid (ALA, 18:3, \\(\omega-3\\)) are all classified as omega-3 fatty acids because their first double bond is located at the third carbon from the methyl end.
3. Step 3: Examine the structure of Arachidonic acid (20:4, \\(\omega-6\\)). Arachidonic acid is a polyunsaturated fatty acid, but its first double bond is located at the sixth carbon from the methyl end, making it an \\(\omega-6\\) fatty acid, not an \\(\omega-3\\).
4. Step 4: Compare the classifications. Since omega-3 fatty acids are defined by the position of the first double bond at the third carbon, Arachidonic acid (20:4, \\(\omega-6\\)) does not belong to the omega-3 category.
5. Step 5: Conclude that the correct answer is Arachidonic acid (20:4, \\(\omega-6\\)), as it is not an omega-3 fatty acid but rather an omega-6 fatty acid.