Walnuts can be a healthy and nutritious food for people with thyroid disorders, including those with hypothyroidism (an underactive thyroid) and hyperthyroidism (an overactive thyroid). Walnuts are a good source of fiber, protein, and other nutrients that can help support overall health and well-being. They are also a good source of omega-3 fatty acids, which are essential fats that play a important role in brain and heart health.