Act as a certified nutritionist with 10 years of experience specializing in micronutrients and immune health. Write a detailed explanation of how [zinc] supports the immune system, focusing on its role in [cellular function], [antioxidant activity], and [wound healing]. Include specific dietary sources of zinc, such as [seafood], [legumes], and [nuts], and explain how [daily recommended intake] varies by age, gender, and health conditions. Conclude with practical tips for optimizing zinc absorption and avoiding deficiencies, especially for individuals with [vegetarian diets] or [chronic illnesses].