Nutritional iron
First, human understanding of iron
Iron deficiency anemia is one of the four major nutritional deficiencies confirmed by the World Health Organization.
In the18th century, Menghini used magnets to absorb particles in dried blood and noticed that blood contained iron.
In 1892, Bunge noticed that infants are prone to iron deficiency.
1928, MacKay proved for the first time that iron deficiency was the cause of the prevalence of infantile anemia in East London. She also believes that providing iron-fortified milk powder can alleviate anemia.
1932, Castle and his colleagues confirmed that inorganic iron can be used for the synthesis of hemoglobin.
Second, the distribution of iron
Iron is an essential trace element for human body. The total amount of iron in human body is 4-5g, which is an important part of hemoglobin. People need it all over their bodies. This mineral already exists in red blood cells that supply oxygen to muscles, and it still needs many enzymes and immune system compounds. The human body takes most of the iron it needs from food, and carefully controls the iron content.
Third, the proper daily intake of human body.
Age of pregnant women, daily intake
0-0.5 years old 0.3mg early 15mg
0.5 years old-1 year old 10mg metaphase 25mg
1-4 years old 12mg late 35mg
4-7 years old 12mg lactation 25mg
7 years old-1 1 year 12mg
1 1 year-old-14 year-old male 16mg female 18mg
14 years old-18 years old male 20mg female 25mg.
18-50 years old male 15mg female 20mg
50 years old 15mg
Fourthly, the physiological function of iron.
1, iron is an important component of hemoglobin, and the function of hemoglobin is to transport oxygen to cells and take carbon dioxide out of cells. The link structure of heme and tetraglobulin in hemoglobin provides an effective mechanism, that is, it can combine with oxygen without being oxidized, and plays a key role in the transport of oxygen from lung to tissue.
2. Myoglobin is composed of heme and globulin chains, and exists only in muscle tissue. Its basic function is to transport and store oxygen in muscles.
3. Cytochrome is a series of heme compounds. Through its electron conduction in mitochondria, it has a very important influence on respiration and energy metabolism. For example, cells A, B and C are necessary to generate energy through oxidative phosphorylation.
4. Iron in other iron-containing enzymes can be non-heme iron, NAP dehydrogenase and amber dehydrogenase, which participate in energy metabolism, as well as heme-iron-containing catalase, poly-oxidase (involved in trihydroxy acid cycle), phosphoenolpyruvate kinase (rate-limiting enzyme in sugar production pathway) and nucleotide reductase (enzyme needed for DNA synthesis).
5. Iron catalyzes the transformation of β -carotene into vitamin A, the synthesis of purine and collagen, the production of antibodies, the transport of lipids in blood and the detoxification of drugs in liver. Iron is also closely related to immunity. Studies have shown that iron can improve the body's immunity, increase the phagocytic function of neutrophils and phagocytes, and enhance the body's anti-infection ability.
Verb (abbreviation for verb) lacks symptoms and consequences.
1. Anemia: In severe cases, it can increase the mortality rate of children and mothers and obviously reduce the working ability of the body.
2. Behavior and intelligence: Iron deficiency can cause damage to psychological activities and intellectual development and behavior changes. Iron deficiency (lack before anemia) will also damage children's cognitive ability, and it is difficult to recover after iron supplementation in the future. Animal experiments show that short-term deficiency can reduce the iron content in the brain of young animals. In the future, iron supplementation can correct iron storage in the body, but it has no effect on iron in the brain. Long-term iron deficiency will obviously affect physical endurance. The animal experiments carried out by Finch et al. show that the damage of iron deficiency to the running ability of animals has nothing to do with the level of hemoglobin, but is caused by the damage of muscle oxidative metabolism caused by iron deficiency.
In terms of immunity and anti-infection ability, both human and animal experiments have recorded that one of the characteristics of iron deficiency is the decline of anti-infection ability.
1. In terms of body temperature regulation, another feature of iron deficiency anemia is that the ability to maintain body temperature in a cold environment is impaired.
2. In the aspect of lead poisoning, animal and human experiments have proved that iron deficiency will increase the absorption of lead.
3, some pregnancy consequences, sweaty bowel disease research shows that anemia in early pregnancy is related to premature delivery, low birth weight infants and fetal death.
Symptoms of iron deficiency include pale skin, tongue pain, fatigue or weakness, loss of appetite and nausea.
Effect of iron deficiency on immune system;
1. The ability to resist the invasion of pathogenic microorganisms is weakened.
2. Reduce the reaction speed of immune cells from rest to war.
3. Reduce the activity of antioxidant biochemical enzymes.
4. Antibody production stops or proceeds at a very slow speed.
5. Iron deficiency anemia, insufficient oxygen supply to cells. The result is listless, tired and tired all day, and more susceptible to infection.
Excessive free iron flowing in the blood will not only help to resist and protect the human body, but will be swallowed up by bacteria and become food for bacteria, which will multiply in large numbers. This is why we must be more careful when we supplement iron for our children.
Six, the main food source of iron
Rich in resources: animal blood, liver, chicken gizzard, bovine kidney, soybean, black fungus, sesame paste, beef and mutton, clams and oysters.
Good sources: lean meat, brown sugar, egg yolk, pig kidney, sheep kidney, dried fruits (dried apricots and raisins), beer yeast, seaweed, brown sugar paste and wheat.
General sources: fish, grains, spinach, lentils, peas, mustard leaves, broad beans and melon seeds (pumpkins, zucchini and other seeds).
Trace sources: dairy products, vegetables and fruits.
In addition, cooking tomatoes or other acidic foods in a cast iron pot can also supplement iron, and the pot will put healthy iron into the food.
It seems that many foods contain iron, but China is still a country with serious iron deficiency, mainly women, children and the elderly. Scientific iron supplementation is essential every day!
There are two forms of iron in food:
Nonheme iron. Trivalent iron mainly combines with protein and organic acids to form a complex. This form of iron must be separated from organic matter and reduced to divalent iron before it can be absorbed. If there is more phytic acid or phosphoric acid in the diet, it will form insoluble iron salt with iron, which will affect absorption. Ascorbic acid and cysteine can reduce trivalent iron to divalent iron, which is beneficial to iron absorption.
Iron (Fe) is a component of hemoglobin, myoglobin and many enzymes in the body. Heme iron mainly exists in animal products, which is much better than non-heme iron, which accounts for more than 85% of iron in general diet. However, when ingested with animal protein and vitamins, it can improve the absorption of non-heme iron.
Iron demand, iron metabolism and iron deficiency anemia are discussed in section 127 anemia caused by erythropoiesis deficiency. Section 127 discusses iron-negative diseases.
Iron deficiency can lead to anemia, which is the most common malnutrition in the world. Some infants, adolescent girls and pregnant women suffer from iron deficiency anemia due to insufficient iron intake. Anyone who loses blood will have iron deficiency. All people with iron deficiency need iron supplementation.
Excessive iron poisoning is toxic, which can lead to vomiting, diarrhea and intestinal damage. When a person receives iron treatment for too long or too long, or receives repeated blood transfusions, or has chronic alcoholism, iron will accumulate in the body. Iron deficiency disease (hemochromatosis) is a potentially fatal but treatable hereditary disease, which absorbs too much iron; Affected 1 10,000 Americans.