The dietary risk factors on cancer patients receiving chemotherapy and correlation between serum vitamin D and B12 levels, depression and anxiety status.

Objective: the aim of this study is to evaluate the relationship between serum vitamin D and B12 levels, nutritional levels, depression, and anxiety in adult cancer patients before and after chemotherapy. Methods: a case-controlled study was carried out on 44 patients who were diagnosed with cancer and applied to the Chemotherapy Unit for treatment (patient group, PG) and 44 volunteer individuals (control group, CG) with similar characteristics to the age and gender-matched patient group but with no diagnosis of cancer. Results: the average age of individuals in PG is 52.50 ± 12.21 years and for those in CG is 52.84 ± 10.98 years. Serum D and B12 levels in the first cure in individuals in PG are higher than in the last treatment (p > 0.05). It was determined that vitamin C taken with a daily diet reduces the risk of cancer (OR: 0.920, 95 % CI: 0.899-0.942, p = 0.042). No correlation was found between depression and anxiety scores of both groups and serum vitamin D and B12 levels (p > 0.05). It was determined that the Beck Anxiety Inventory (BAI) score increased with decrease in body mass index (BMI) (β = 0.311, p = 0.040) and serum vitamin B12 level (β = -0.406, p = 0.006). In addition, it was found that the increase in the Patient-Generated Subjective Global Assessment (PG-SGA) score, which reflects the nutritional status of cancer patients, worsened the level of anxiety (β = 0.389, p = 0.009). Conclusions: as stated in the findings of the study, chemotherapy treatment mediated the development of anxiety in cancer patients by changing the vitamin B12 levels and anthropometric characteristics with its negative effect on nutritional status. It should be ensured that cancer patients treated with chemotherapy follow a healthy and balanced diet plan that is suitable for their needs and has adequate vitamin and mineral content.