Phase angle (PhA), measured by bioelectrical impedance analysis, indicates cellular health, integrity, and function. As inflammation can damage cells, phase angle may be useful in detecting inflammatory status early. The relationship between dietary inflammatory index (DII) and PhA has not been studied yet. Therefore, we aimed to examine this association in Iranian adults. This cross-sectional study included 206 university employees. Dietary intakes were assessed by using a validated 86-item food frequency questionnaire (FFQ). Anthropometric indices and blood pressure were measured. A short form of the validated International Physical Activity Questionnaire (IPAQ) was used for evaluating physical activity. The PhA was measured by the Body Composition Analyzer Mc780 MA device. The mean age of participants was 43.50 ± 8.82 years and the range of DII score was − 4.66 to 0 among them. The highest tertile of DII compared to the lowest tertile, showed greater weight, WC, HC, basal metabolic rate (BMR), and diastolic blood pressure. We found no significant association between DII and PhA (crude model: OR: 0.68; 95% CI 0.34, 1.33, fully-adjusted model: OR: 0.65; 95% CI 0.26, 1.64). Also, after BMI stratification this association remained (fully-adjusted: normal weight: OR: 0.61; 95% CI 0.11, 3.27; Overweight and obese: OR: 0.57; 95% CI 0.16, 1.98). Having a higher DII score was not associated with a lower PhA. Further well-controlled prospective studies are warranted.

Phase angle (PA), derived from bioelectrical impedance analysis, serves as an indicator of cellular health, membrane integrity, and hydration status. Despite its potential utility, the relationship between PA and nutritional and lifestyle factors has not been extensively studied in Iranian populations. This study aimed to investigate these associations in Iranian adults. This cross-sectional study included 239 university employees (85 men and 154 women) with a mean age of 43.32 years. Anthropometric indices and blood pressure were measured. PA was measured by the Body Composition Analyzer Mc780 MA device. Dietary intakes were assessed by using a validated 86-item food frequency questionnaire (FFQ). Physical activity was evaluated by the short form of the International Physical Activity Questionnaire (IPAQ). Associations between PA and study variables were analyzed using Pearson’s correlation and Linear Regression. Significant positive correlations were observed between PA and several anthropometric and body composition indices, including weight, body mass index (BMI), waist circumference (WC), hip circumference (HC), fat-free mass (FFM), muscle mass, bone mass, and visceral fat. PA showed significant associations with dietary intake variables. This study highlights significant associations between PA and body composition and dietary factors in Iranian adults, with notable sex-based differences. These findings suggest that PA may be a valuable marker for assessing nutritional and cellular health.