Nutrient Information: 铁 Iron, Fe

Vitamin C helps convert ferric iron (Fe3+) found in plant-based foods into ferrous iron (Fe2+). Ferrous iron is more soluble and easier for the body to absorb in the small intestine. So including vitamin C-rich foods or beverages in the meals containing iron-rich plant foods can significantly improve iron absorption.

Both iron and manganese use and compete Divalent Metal Transporter 1 (DMT1) for uptake them into intestinal cells. Iron supplements can inhibit manganese absorption more significantly than dietary iron because supplements provide a concentrated source of iron.

The body's iron stores influence the expression of DMT1. When iron stores are low (iron deficiency), the body upregulates DMT1 to increase iron, as well as manganese, absorption. Conversely, when iron stores are high, DMT1 expression is downregulated, which can reduce the absorption of both iron and manganese.

Iron and zinc share a common absorption pathway in the intestines, high concentration of one mineral can potentially inhibit the absorption of the other due to competition for this transporter. In addition, iron supplements can form insoluble complexes with zinc in the gastrointestinal tract, that reduce the availability of zinc for absorption.

When taking high bioavailability Ferrous Sulfate iron supplement, especially without food, the impact to the zinc absorption is more pronounced. The higher the iron supplement dosage, the severe the zinc absorption reduction. It is true vice versa.

Recommend to separate the intake of iron and zinc supplements by a few hours to reduce direct competition for absorption. It is better to obtain heme iron from animal products which is less likely to interfere with zinc absorption, and also make sure to get sufficient zinc from food sources such as meat, shellfish, seeds, nuts, cheese, and whole grains.

Several studies have shown that calcium, whether from food or supplements, can reduce the absorption of non-heme iron (found in plant-based foods) when they are consumed simultaneously. The calcium-iron complexes that form in the intestine reduce the amount of iron that can be absorbed. However, this inhibitory effect is temporary.

To optimize iron absorption, it is better to consume calcium-rich foods or supplements at different times than iron-rich meals, especially meals containing iron-rich vegetables.