Background: One of the most frequent and serious adverse effects of chemotherapy for patients with breast cancer is myelo suppression, especially neutropenia. There have been suggestions for nutritional treatments to boost immunological function. However, evaluating their separate effects on white blood cell (WBC) recovery is made more difficult by the concurrent administration of Filgrastim. This study examines how nutrition affects WBC counts in patients undergoing chemotherapy who are on Filgrastim. Methods: This is a randomized, parallel-group clinical trial with 52 participants in each arm that includes adult women with newly diagnosed breast cancer who are recommended for chemotherapy at a cancer treatment day care center at the National Institute of Cancer Research and Hospital (NICRH), Dhaka. The results were measured using a semi-structured questionnaire that had been pretested. Since the only intervention group received three hen-boiled eggs (one entire and two only white parts) daily, one omega-3 fatty acid tablet, and one vitamin D tablet (2000 I U), no placebo was utilized in this trial due to ethical concerns and convenience. Machine SYSMEX XN 350, an automated cell counter, performed the hematology analysis. Blood samples were taken and brought to the lab while taking every aseptic care. Statistical study evaluated differences between and between groups while taking Filgrastim’s impact into account. Results: There was a significant difference between the intervention and control groups (p = 0.021), with a small drop in the total WBC count in both groups. While neutrophil levels stayed constant, lymphocyte percentages fluctuated somewhat. In both groups, the percentage of monocytes increased significantly (p = 0.003, p < 0.0001). The intervention group’s basophil percentage rose noticeably (p = 0.031). The results demonstrate how challenging it is to separate the pharmacologic effects of Filgrastim from the effects of diet. Conclusion: There is conflicting evidence on the impact of nutritional interventions on WBC recovery in chemotherapy patients receiving Filgrastim, despite the fact that they may enhance immune function. Future studies should look into study designs that more clearly differentiate pharmaceutical effects from nutritional contributions, as well as alternative immunological biomarkers besides WBC counts.