Haematological and toxicological effects of commercial citric acid (e330) samples sourced from Kano metropolis, Nigeria *

Abstract

Citric acid (E330) is a widely used food additive, but limited toxicological data exist on locally sourced formulations. This study evaluated the acute, sub-acute, and combined oral toxicity of commercially available anhydrous, monohydrate, and mixed citric acid from Kano metropolis, Kano State, Nigeria, using male Wistar albino rats. For acute toxicity, single oral doses of 1,000, 3,000, and 5,000 mg/kg were administered, and mortality and clinical signs were monitored for 14 days. Sub-acute toxicity was assessed over six weeks using low, medium, and high doses derived from the LD₅₀ values obtained in the acute study (Anhydrous: 41.75–334 mg/kg; Monohydrate: 73.4–587 mg/kg; Combined: 27.5–220.6 mg/kg). Haematological parameters, including White Blood Cell (WBC), Red Blood Cell (RBC), Haemoglobin (HGB), Haematocrit (HCT), Mean Corpuscular Volume (MCV), Mean Corpuscular Haemoglobin (MCH), Mean Corpuscular Haemoglobin Concentration (MCHC), Platelets count (PLT), and lymphocytes, were analyzed. Results indicated significant (P ≤ 0.05) dose – and formulation – dependent alterations in haematological indices. Low-dose anhydrous citric acid increased WBC (8.12 × 10⁹/L), RBC (8.21 × 10¹²/L), and HCT (43.5%), whereas high doses reduced RBC and HGB but elevated lymphocytes and PLT. Monohydrate citric acid caused increased WBC (8.65 × 10⁹/L) and HGB (15.3 g/dL) at low doses, while high doses elevated lymphocytes and PLT. Combined formulations at low doses increased RBC (7.88 × 10¹²/L), HGB (14.8 g/dL), HCT (42.3%), MCV (53.2 fL), and MCH (18.4 pg), whereas high doses decreased MCH, MCHC, and HCT. These alterations suggest erythropoietic and immunological modulation, with potential dehydration – or toxicity – related effects at higher doses. In conclusion, oral exposure to locally sourced citric acid, particularly at high doses and in combined formulations, may induce measurable haematological changes. Thus, these findings underscore the importance of evaluating the safety of locally sourced food additives before consumption.