Here, we will try to find out the answers of very frequent asking questions. Can we take iron supplements or food and calcium supplements or food together? What will happen when we take them together? When we take both of them together, will we become anemic? First of all, we will discuss very briefly about iron,
ABOUT IRON
Iron is an important mineral and essential micronutrient which play a vital role in different physiological, cellular and neurological functions and in hormonal, enzyme and DNA synthesis, in erythropoiesis, oxygen transportation and immune function.
DIETARY IRON
Dietary iron is available in 2 forms,
HEME IRON OR ABSORABLE DIETARY IRON
It is basically derived from the hemoglobin or myoglobin of animal food sources as poultry, sea food or meat. It is readily absorbable form of dietary iron due to availability of specific heme transporter which enhance its absorption from small intestine. It is less affected by dietary factors.
NON-HEME IRON OR LESS ABSORABLE IRON
It is basically derived from plant sources and fortified food. It is less absorbable form of dietary iron because require reduction of ferric iron or oxidize iron (Fe+3) into ferrous iron (Fe+2) before absorption. Its absorption is affected by dietary factors. After reduction, it is transported from intestinal enterocyte into blood stream via Divalent metal transporter 1(DMT1).
Eggs and dairy products are also non heme iron. Animal flesh also contain
non heme iron along with heme iron.
FOOD ENHANCER FOR NON-HEME IRON
Vitamin C, vitamin A, beta carotene and protein enhance the absorption of non heme iron.
FOOD INHIBITORS FOR NON-HEME IRON
Calcium, poly phenols and phytates inhibit absorption of non heme iron.
PROCESS OF NON-HEME IRON ABSORPTIO
For the absorption of non heme iron in the low gastric PH of proximal duodenum (mildly alkaline environment), iron is converted from ferric (insoluble state) to ferrous (soluble state) through a ferric reductase enzyme and duodenal cytochrome B (Dcytb) located on the brush boarder of enterocytes of duodenum.
After reduction or in simple words solubilization, ferrous ion (Fe+2) is up taken into enterocytes from the lumen of intestine via transmembrane influx protein transporter DMT1 (Divalent metal ion transporter) which not only transport ferrous ion but also supposed to be transport others divalent cations like manganese, cobalt and copper.
Once ferrous ion (Fe+2) is entered into enterocyte, there may be storage of iron in enterocyte or efflux of iron from enterocyte into circulation take place depending upon demand of iron with in the body. If iron demand is low then there will be storage of iron into enterocyte as ferritin (iron storage protein complex) but if body iron demand is high then there will be efflux or exit of iron into circulation via efflux transporter ferroportin (FPN1).
After entering into circulation, iron is first oxidizing from ferrous state (Fe+2) to ferric state (Fe+3) via hephaestin for systemic distribution via binding with apo transferrin and form transferrin (transporting protein complex).
SHORT TERM AND LONG-TERM IMPACT OF CALCIUM ON IRON ABSORPTION
Inhibitory effect of calcium on iron absorption is for short duration possibly by interfering with regulation of transmembrane proteins responsible for absorption and transporting iron into circulation. However, on long term the impact of calcium on iron absorption is insignificant because of rebound effect which regulate iron absorption mechanism to maintain iron homeostasis.
POSSIBLE MECHANISM OF ACTION OF CALCIUM ON IRON ABSORPTION
Several studies have indicated that calcium decreases iron absorption (affect both heme and non heme iron) by influencing iron transporting protein. Initially it was supposed that calcium effect iron absorption by influencing DMT1 transport protein responsible for entering of non heme iron into enterocyte but later it was discussed that receptors for entering into enterocyte of both heme and non heme iron is different than influence of calcium on iron absorption through affecting DMT1 became irrelevant. Now it is supposed that calcium affects iron absorption by influencing export transporter protein like FPN1(efflux of iron from enterocyte to circulation). According to some theory calcium and iron compete for same receptors which can inhibit iron absorption. One more possible mechanism of action is that calcium by binding with intestinal iron form insoluble complex which will not allow its absorption. However, exact mechanism of action of calcium on iron absorption is still remain to be elucidated.
CONCLUSION
We can conclude that for optimal absorption of iron and calcium from iron and calcium supplements respectively, (especially in iron and calcium deficiency vulnerable population like women and children) it is better the intake of both of them should be separated by a few hours. However, in the light of evidences from long term studies it is indicated calcium supplements taken simultaneously or separately from meal doesn’t affect iron status. In regular diet, because of the presence dietary factors inhibitory effect of calcium on iron absorption is of less significance when taken simultaneously. Despite the popular belief (calcium and iron supplements or food shouldn’t be taken simultaneously), we cannot justify this belief because of evidences of compensatory mechanism exist for iron regulation. So, there is no problem at all (you not be anemic) when both of them taken simultaneously.
