HP and obesity due to melanocortin 4 receptor deficiency: Altogether, the findings observed so far in the present and other studies of an association between increased levels of zonulin and elevated risk of overweight, obesity, and hyperlipidemia, suggest that elevated zonulin levels may rather be a biomarker of obesity, metabolic syndrome, and low-grade inflammation, than of increased intestinal permeability [3,13,14,16].