Effect of dietary protein on serum hepcidin and iron in adults with obesity and insulin resistance: A randomized single blind clinical trial.

Background and aims: Both obesity and iron deficiency are public health problems. The association between the two problems could be explained by chronic low-grade inflammation in obesity, which could stimulate hepcidin expression and modify iron concentration that the consumption of high-protein diets could prevent. Thus, this study aimed to compare the effects of high-protein diets with a predominance of animal or vegetable protein on serum hepcidin and iron concentrations in adults with obesity.

Methods and results: This randomized clinical trial involved adults with obesity and insulin resistance, who were assigned to either a high animal protein (AP) group or a high vegetable protein (VP) group for a one-month intervention. Both groups followed a calorie-restricted diet, reducing energy intake by 750 kcal/day. Baseline and final measurements included serum concentrations of hepcidin and iron, biochemical parameters, anthropometric data, and body composition. A total of 33 participants (63 % female) were included in the study. Significant weight loss was observed in both groups after the intervention. Adjusted for weight loss percentage, the AP group showed a significant increase in hepcidin concentration (from 22.3 ± 14.7 to 27.5 ± 19.5 ng/mL) compared to the VP group (from 17.9 ± 15.1 to 17.2 ± 10.1 ng/mL) (p < 0.01), with no changes in serum iron concentration. Additionally, the VP diet significantly reduced serum adiponectin (p = 0.04) and C-reactive protein (p = 0.03) levels.

Conclusions: In adults with obesity following the AP diet for one month, hepcidin levels increased without affecting serum iron concentrations.

Trial registration: NCT03627104.