Adjunctive Nigella sativa Supplementation Enhances Selected Metabolic and Oxidative-Stress Responses to Combined Aerobic–Resistance Exercise in Men with Type 2 Diabetes Mellitus: A Randomised Controlled Trial

Type 2 diabetes mellitus (T2DM) is increasingly managed through lifestyle measures, yet the value of pairing structured exercise with a well-characterised phytotherapeutic adjunct remains poorly defined. We examined whether adding Nigella sativa (NS) to combined aerobic and resistance exercise (EX) yields greater improvements in metabolic, inflammatory, and oxidative-stress markers than exercise alone in men with T2DM. In this three-arm randomised controlled trial, 90 sedentary, non-smoking men (aged 40–60 years; T2DM duration > 2 years; glycated haemoglobin (HbA1c) 6.5–9.0%; body mass index (BMI) < 30 kg/m2) were allocated 1:1:1 to control, EX, or EX + NS (2 g/day; n = 30 per group) for four weeks. Fasting blood samples obtained before and after the intervention were used to measure glycaemic indices (fasting blood glucose (FBG) and fructosamine), a lipid panel (total cholesterol, triglycerides, low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c)), inflammatory markers (tumour necrosis factor-α (TNF-α), interleukin-4 (IL-4), and adiponectin), and oxidative-stress markers (thiobarbituric acid–reactive substances (TBARS) and catalase activity). Outcomes were analysed by two-way repeated-measures analysis of variance (time × group), with partial eta-squared (ηp2) and 95% confidence intervals (CIs) reported for all principal effects. Relative to control, both exercise arms significantly improved body composition and glycaemic, lipid, inflammatory, and oxidative-stress profiles (all p < 0.05). The time × group interaction was significant for every outcome except systolic and diastolic blood pressure and triglycerides. Compared with EX alone, EX + NS produced significantly greater improvements in FBG, HDL-C, TBARS, and catalase activity; changes in fructosamine, total cholesterol, TNF-α, IL-4, and adiponectin favoured EX + NS directionally but did not reach significance after correction for multiple comparisons. Triglycerides, LDL-C, and blood pressure did not differ between the two exercise arms. These hypothesis-generating findings support NS as a candidate adjunct to structured exercise for selected metabolic and redox outcomes, and warrant larger, longer, sex-balanced confirmation.