It is essential to first consult a healthcare professional and undergo blood tests to determine your specific deficiencies before starting any supplement regimen. Common nutrients often assessed postpartum include Omega-3, Vitamin D, Vitamin B12, and Magnesium. Since muscle loss is a common concern for nursing mothers, focus primarily on increasing your intake of high-quality protein, complex carbohydrates, and healthy fats through your diet. A registered nutritionist can help you create a balanced eating plan that meets the caloric demands of breastfeeding while addressing your specific nutritional gaps.