Iron deficiency is common
Due to improper dietary intake or the limitation of the level of economic development, iron deficiency has been one of the nutritional deficiency diseases that cannot be ignored. The survey on the nutrition and health status of Chinese residents shows that iron and other micronutrient deficiency is a common problem among urban and rural residents in China.
Iron is one of the essential micronutrients and deficiency can lead to iron deficiency anemia (weakness, dizziness, palpitations, spoon nails, etc.) and low immune function.
Iron deficiency in children can also lead to low cognitive ability, stunted growth, abnormal behavior (xenophagia), etc;
Iron deficiency in pregnant women can cause premature birth, low birth weight babies and even fetal death.
The main factors affecting iron absorption are the chemical form of iron and bioavailability. The chemical form of iron is divided into two categories according to the absorption mechanism: heme iron and non-heme iron.
Heme iron
It is mainly found in animal foods, such as liver, whole blood, meat and fish, and can bind directly to hemoglobin with high bioavailability. It is mainly regulated by iron nutritional status, with an average absorption rate of 25%, and the absorption rate of heme iron can reach 40% when iron is deficient and 10% when it is not. It is a good source of iron for human body.
Non-heme iron
It is mainly from plant foods, dairy products, ferritin and iron supplements, such as dark green vegetables, black fungus, black rice, etc. It accounts for most of the dietary iron (90%). Non-heme iron is mainly in the form of trivalent iron, which must be broken down by gastric acid and reduced to ferrous ions (divalent iron) before it can be absorbed through the mucous membrane cells of the small intestine, so its absorption rate is very low, averaging about 7.5%, which can be increased to 21% when iron is deficient and reduced to 2.5% when iron is sufficient.
Non-heme iron absorption is greatly influenced by diet
Components that promote absorption: vitamin c, meat, fish, seafood and certain organic acids.
Factors that hinder absorption: lack of stomach acid, dietary factors (oxalic acid, phytic acid, polyphenols, calcium, etc.).
Phytic acid is widely found in grains, seeds, nuts, vegetables and fruits.
Foods high in polyphenols include tea, coffee, cocoa and spinach (tea and spinach are rich in iron, but also high in polyphenol compounds).
Therefore, non-heme iron has low bioavailability and is not a good source of iron.
How to prevent iron deficiency?
Because the majority of our diet is non-heme iron, the utilization rate is very low, so how can we ensure that we do not have iron deficiency?
1, the best daily diet with vitamin C, vitamin A high content of food to improve its utilization.
2, to diversify food, to ensure the intake of fish and meat.
3, less coffee, strong tea, especially iron deficient people.
4, animal food to minimize the long time high temperature cooking (long time high temperature cooking will make heme iron decomposition into non-heme iron).