Jernærings

Jernærings is a term used to describe the study of iron nutrition in living organisms, including how iron is absorbed, transported, stored and utilized. Iron is essential for oxygen transport in blood, cellular respiration and many enzymes, making it a focus of both human health and plant biology. In humans and other animals, iron status is tightly regulated to balance needs with the risk of toxicity.

In human nutrition, iron is absorbed mainly in the duodenum and upper jejunum. Heme iron from animal sources is typically absorbed more efficiently than non-heme iron from plants. Non-heme iron absorption is influenced by enhancers such as vitamin C and inhibitors including phytates, polyphenols and calcium. The hormone hepcidin regulates iron balance by limiting iron export from cells. Stored iron is predominantly in ferritin, while circulating iron is carried by transferrin; transferrin saturation and ferritin levels are commonly used to assess status. Iron deficiency can lead to anemia with fatigue and reduced function, particularly among women of childbearing age, infants and those with restricted diets. Excess iron, though less common, can cause toxicity and organ damage, especially in genetic conditions like hemochromatosis.

In plant nutrition, iron availability is strongly affected by soil pH. Non-graminaceous plants use Strategy I to reduce Fe3+ to Fe2+ and transport it into roots, while graminaceous plants use Strategy II, secreting phytosiderophores to solubilize and uptake Fe3+. Iron chlorosis is a common symptom of deficiency in high-pH soils. Management includes soil pH adjustment and the use of iron chelates or fortified fertilizers.

Overall, jernærings covers the physiological, biochemical and agronomic aspects of iron acquisition and use, with practical implications for diet, health and crop production.