Co-administration of curcumin forms with supplemental iron: a study of effects on iron absorption and intestinal...

Iron deficiency (ID) and iron deficiency anaemia (IDA) are significant global public health issues, with their main line of treatment being oral iron supplementation that often leads to gastrointestinal (GI) adverse effects and early discontinuation. Strategies to improve the efficiency of oral iron supplements and to ameliorate their associated GI effects could help resolve ID and IDA. Curcumin, a potent antioxidant and anti-inflammatory, iron chelating compound from turmeric may mitigate some of these issues. This study aimed to mechanistically assess the interaction of iron (20 and 100 μM) with two different forms of curcumin - native, unformulated curcumin versus a formulated curcumin (HydroCurc®) at 5, 10 and 20 μM, and the consequent effects on iron uptake and intestinal cellular health. Presence of formulated curcumin incremented ferritin levels by 160.5% versus free iron treatment alone (p < 0.0001) in intestinal Caco-2 cells. A greater ferric iron reducing power by the formulated curcumin was observed (p < 0.001). Formulated curcumin also protected against iron-induced permeability of the intestinal barrier (p < 0.05). Our data points to formulated curcumin's ability to limit oxidation of divalent iron as a possible mechanism to explain the greater iron uptake by intestinal cells. This study characterises for the first time the distinct interaction behaviour of curcumin forms with iron and the potential consequences on iron uptake and intestinal health, providing novel insights that may help optimise therapeutic approaches to tackle ID and IDA.