Effects of oat protein on hematological parameters and metabolism in Wistar rats

Diets rich in plant-based proteins are becoming increasingly popular, but the safety of extracted oat (Avena sativa L.) protein in relation to cardiometabolic and endocrine risks remains unexplored. This study evaluated the safety of oat protein by analyzing anthropometric, hematological, biochemical, and histopathological parameters in male Wistar rats fed high-protein diets for 30 or 90 days.

Animals were divided into four diet groups (n = 6 per group): oat protein-supplemented (G1), soy protein-supplemented (G2), casein-supplemented (G3), and control (G4). After 30 days, the oat protein group had significantly higher leukocyte (P = 0.018) and lymphocyte (P = 0.001) counts than the other groups. After 90 days, this group had significantly lower erythrocyte counts (P = 0.007), hemoglobin levels (P = 0.017), hematocrit values (P = 0.011), total leukocyte counts (P = 0.001), lymphocyte counts (P = 0.001), and platelet counts (P = 0.001) than the other groups. Oat protein supplementation improved lipid parameters, reducing low-density lipoprotein (LDL) cholesterol (P = 0.034) after 30 days and triglycerides (P = 0.003) and very-low-density lipoprotein (VLDL) cholesterol (P = 0.003) after 90 days, with effects similar to those observed in the casein group. Increased creatinine levels (P = 0.005) were observed in the oat protein group after 30 days, suggesting a transient renal effect. Histopathological analysis revealed mild to moderate alterations in liver and kidney tissues, including neutrophil infiltration in all groups and the presence of macrophages and mononuclear cells in the renal interstitium.

Although oat protein supplementation improved lipid profile parameters, prolonged high intake was associated with hematological alterations and transient renal changes. These results highlight the need for caution in the use of high-protein diets based on plant sources and underscore the importance of further studies to clarify their long-term safety. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.