MC4R and Abdominal obesity: Among nutrients (iron, zinc and magnesium), Iron had an interaction with MC4R SNP in the development of abdominal obesity (P interaction = 0.006); in A allele carriers, the risk of abdominal obesity did not change significantly with increased iron consumption (P trend = 0.50) whereas for GG genotype carriers, higher consumption of iron led to an increase in the risk of abdominal obesity (P trend = 0.002) (Fig. 2).