The aim of this study is to establish the ideal clinician's approach to nutritional bicytopenia in the context of adequate micronutrient supplementation. We present the case of a 27-year-old patient living with obesity, subjected for months to a very low-calorie diet and adequate supplementation with complementary vitamins and minerals, evaluated and treated for bicytopenia with irondeficiency anemia and lymphocytopenia. The use of meal replacement supplements as nutritional sources replacing food items requires medical supervision as they can have consequences on the patient's micronutrient balance. Classically, and frequently, iron-deficiency anemias have been identified as the most common condition in these restrictive nutritional regimens. However, alterations in the white cell line are more frequent than believed and may be associated with multiple nutritional deficiencies including folic acid and vitamin B12. The diagnostic approach becomes complex when the most common nutritional causes are hidden by replacement supplements. The patient achieved an increase in hemoglobin after treatment (12.3 g/dL), recovering from anemia. When approaching nutritional cytopenias, the primary takeaway should always be the thinking process. Every patient with bicytopenia must be studied particularly meticulously, and the good clinician is forced to address it and reach the most likely diagnosis within the common and the rare.

Keywords: Anemia, folic acid, iron-deficiency anemia, leukopenia, lymphopenia, vitamin B12