Get to know blood circulatory system in the body
The circulatory system delivers nutrients and oxygen to all cells in the body. The average blood volume of an adult is generally equivalent to 1/12 of the total body weight. For example, an adult weighing 60 kg. They should have about 5 liters of blood in their bodies. The main components of blood include plasma, red blood cells, white blood cells, and platelets. Iron is considered an essential element for blood production. The human body usually contains 40-50 mg/kg of iron. Iron is present in red blood cells in the form of hemoglobin and is stored in the liver and spleen. The production of red blood cells, called erythropoiesis, is produced in the bone marrow under the control of the hormone erythropoietin. They are responsible for transporting oxygen from the lungs to body tissues and have an average lifespan of about 120 days. At 120 days, our red blood cells are naturally destroyed by macrophages in the liver and spleen. During the destruction process, iron attached to red blood cells is released back into the circulatory system and reused as an important component of hemoglobin and new red blood cell production. Necessary nutrients for the production of red blood cells are iron, folic acid and vitamin B12.
Iron deficiency and anemia
Anemia is defined as a decrease in the total amount of red blood cells or hemoglobin in the blood. Different types of anemia have different causes. Iron deficiency is the most common cause of anemia. Iron deficiency can be caused by a lack of adequate iron in the daily diet, such as red meat and liver. Vegetarians and vegans can also deplete iron stores. In fact, some vegetables can act as iron absorption inhibitors. An individual's daily recommended intake of iron is influenced by several factors, such as gender, age, growth and physical development, physiological factors, blood loss during menstruation, dietary restrictions, and ongoing health problems. The median daily iron intake for adult men is approximately 10.4 mg and for adult women it is 9.4 - 24.7 mg.
Sources of iron and iron absorption
According to iron absorption, iron can be divided into two main forms:
Heme iron: Heme iron is derived from animals that originally contained hemoglobin, such as red meat, liver, poultry, fish, and seafood. The body can absorb the highest amount of iron from heme, up to 20-30%.
Non-heme iron: Non-heme iron can be obtained from plant foods, such as whole grains, nuts, seeds, beans, green leafy vegetables. Egg yolks and milk also contain non-heme iron. Still, this form of iron is difficult for the body to absorb. Absorption of non-heme iron is significantly affected by dietary components ingested at the same time, with promoting and inhibiting factors playing a key role in the absorption rate of non-heme iron, accounting for only 3-5%.
Dietary planning on iron intake
Vitamin C has been shown to enhance iron absorption. It captures non-heme iron and stores it in a special form that makes it easier for the body to absorb. Foods rich in vitamin C should be eaten along with iron, including citrus fruits, orange juice, and lemonade.
If the daily food contains less than 30 g/day of meat or less than 25 mg/day of vitamin C, the ability to absorb iron from food is limited, only 3-10%.
Iron absorption from food increases slightly to 10-12% if daily food contains 30-90g/day of meat or 25-75mg/day of vitamin C.
If the daily food content of meat exceeds 90 g/day, or the content of vitamin C exceeds 75 mg/day, the absorption of iron from food will greatly increase to more than 15%.
To ensure your daily iron intake, it is recommended to follow the following recommendations:
1. Eat more foods rich in iron (heme), such as meat, liver, chicken, fish, shrimp or prawn offal and edible shells.
2. Keep a sufficient amount of meat, 6-12 tablespoons per day, as it greatly enhances the body's absorption of non-heme iron from food.
3. Eat fruit regularly, 3-5 servings per day, especially citrus fruits rich in vitamin C, to increase iron absorption (non-heme form).
4. If possible, try to eat fresh vegetables and fruits rich in iron, because overheating during cooking can easily destroy vitamin C.
5. Don't drink milk or soy milk with meals, and don't drink iron supplements, because the calcium and phosphates in milk and soy milk can greatly reduce the rate of iron absorption.
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