Tuna and avocado is a delicious combination, and they are both very healthy foods. Tuna is an excellent source of omega-3 fatty acids, which are vital for brain function and heart health. Avocado contains many vitamins and minerals, including potassium, folate, vitamin E, vitamin K, B vitamins (thiamine, riboflavin), vitamin C, calcium, magnesium, phosphorus, iron, zinc and copper. It also contains monounsaturated fat which helps lower LDL cholesterol levels in the blood.