Iron is an essential nutrient for the human body. Iron is one of the essential trace elements for the human body. As early as 1932, scientists confirmed that iron is involved in the synthesis of hemoglobin and basically understood the role of iron in the human body. The main iron-containing chemical groups in the body are iron-sulfur complexes and heme iron. Based on these, many biologically active functional proteins are formed, exerting corresponding physiological functions. 1. Iron is a component of hemoglobin, myoglobin, cytochromes, and some respiratory enzymes, participating in the transport of oxygen in the body and the process of tissue respiration. 2. Maintain normal hematopoietic function. 3. Iron-sulfur proteins are involved in a series of basic biochemical reactions, including regulating enzyme activity, mitochondrial respiration, ribosomal biosynthesis, cofactor biosynthesis, regulation of gene expression, and nucleotide metabolism. 4. Other functions. Iron can catalyze the conversion of ß-carotene to vitamin A, participate in the synthesis of purines and collagen, the production of antibodies, the transport of lipids in the blood, and the detoxification of drugs in the liver. How much iron do we need daily The iron requirement is not only related to the amount of iron lost but also related to the absorption rate of iron and individual differences. 1. Absorption rate. The absorption rate of iron is affected by many factors in the diet and is also closely related to the body's iron nutritional status, the intake of dietary iron, and the proportion of heme iron and non-heme iron in the diet. Generally, the absorption rate for adults is about 10%. The iron absorption rate in the first trimester of pregnancy is similar to that of non-pregnant women, while in the second and third trimesters, the iron absorption rate increases by 1 to 3 times compared to the early stage, around 25%. 2. There are also certain differences in iron requirements among individuals. The human body needs more than 40 nutrients. For most nutrients, men's needs are higher than women's,唯独 the requirement for iron is higher in women than in men. For children under 11, the iron requirement is not differentiated by gender: The recommended iron intake for children aged 1-3 is 9 mg per day. The recommended iron intake for children aged 4-6 is 10 mg per day. The recommended iron intake for children aged 7-10 is 13 mg per day. Iron is more important for women's health After the age of 11, with the onset of puberty, due to increased iron loss, women's iron requirements are significantly higher than men's. The recommended iron intake for females aged 11-13 is 18 mg per day, and for males, it is 15 mg per day. The recommended iron intake for females aged 14-17 is 18 mg per day, and for males, it is 16 mg per day. In the adult stage, the recommended iron intake for women aged 18-49 is 20 mg per day, and for men, it is 12 mg per day. For women over 50, the iron requirement decreases, and the recommended intake is 12 mg per day. Women who are pregnant or breastfeeding not only need to meet their own iron needs but also need to provide enough iron for the child, so their iron requirement is higher: The recommended iron intake for women in the second trimester of pregnancy increases by an additional 4 mg per day, and in the third trimester, it needs to increase by an additional 9 mg per day. The recommended iron intake for lactating mothers increases by an additional 4 mg per day. Where does the iron go The loss of iron in the body mainly includes the following parts. 1. Basic iron loss, which is iron loss through feces, sweat, skin, and urine. 2. Menstrual iron loss. Age, marital status, parity, age of menarche, and cycle length have no significant effect on the amount of menstrual blood. Once a woman's menstrual pattern is established after menarche, before menopause, the amount of blood loss during each period does not change much, with an average daily iron loss of about 0.65 mg. 3. Iron accumulation during growth. As children and adolescents grow and develop, iron can accumulate in the body, including iron accumulation in hemoglobin, increased iron in non-storage tissues, and increased storage iron. Especially during the period of accelerated growth, girls grow faster before menarche, and growth continues after menstruation begins. Therefore, the iron requirement is very high. 4. Special physiological conditions. Such as pregnancy and lactation, due to fetal growth and milk secretion, iron loss will also increase.
Iron content in common foods [(mg/100g edible part)]
This article is excerpted from "Ma Guansheng Talks about Nutrition" by Ma Guansheng, authorized by Phoenix Hanzhang Books, and is strictly prohibited from being reproduced.