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13Iron ( Fe ) for the body - top 30 sources and health implications _
Eliseeva Tatyana, editor-in-chief of the EdaPlus.info project E-mail: eliseeva.t@edaplus.info
Abstract. The article discusses the main properties of iron ( Fe ) and its effect on the human body. A systematic review of modern specialized literature and relevant scientific data was carried out. The best natural sources of iron are indicated . The use of the mineral in various types of medicine and the effectiveness of its use in various diseases are considered. The potentially adverse effects of iron on the human body under certain medical conditions and diseases are analyzed separately.
Key words: iron, iron, Fe , benefit, harm, useful properties, contraindications
Iron is a trace element necessary for transporting oxygen and removing carbon dioxide. When nutrient stores in the body are severely reduced, cells receive less oxygen and iron deficiency anemia (IDA) develops. To prevent this from happening, you need to eat more iron-rich foods. The problem is that they are absorbed differently and absorption can be as low as 2%.
Why does the body need iron: reserves and functions
The body does not produce a substance, but only processes and stores:
• 70% is in hemoglobin, and the rest is in the form of ferritin in the liver, spleen, muscle tissue and bone marrow;
• hormone hepcidin regulates its absorption and distribution in the body;
• transferrin, a protein in blood plasma, delivers the microelement throughout the body . [one]
People lose the mineral in small amounts with urine and feces. Large losses occur with blood loss, which is why many menstruating women suffer from a deficiency. [2]
How to detect anemia: tests that show iron deficiency
Your doctor will usually confirm IDA with a complete blood count (CBC), more specifically hemoglobin and hematocrit tests. Other indicators help to identify the problem in the early stages, determine the severity of the condition and the method of treatment:
• size and color of red blood cells;
• serum ferritin ;
• vitamin B12.
In anemia, hematocrit and hemoglobin levels are low, and red blood cells are smaller than normal. A low ferritin level indicates a low supply of iron and is a harbinger of anemia, so it is advisable to check it as often as possible.
Iron in food - types and absorption
The mineral is found in food in two forms:
• Heme . Absorbed by the body up to 40%. This type of iron comes from animal protein—found only in meat, poultry, organ meats, and seafood (fish, shellfish, etc.).
• Non-heme . It has a low bioavailability of 2-20%. Found in plant foods and animals as animals eat plant foods. [3]
The absorption of the component is complex and one food enhances this process, while the other suppresses it.
Foods rich in iron
According to scientists, 85-90% of the total micronutrient intake is in the non- heme form, and 1015% in the heme form .
15 Animal Foods Highest in Iron [4]
No. Products
In 100
g:
No. Products
one Pork spleen stewed, fried 22.2 mg eight Mussels boiled 2 Fried or stewed pork liver 17.9 mg 9 Beef heart, liver stewed or fried
3 Pork lung boiled
four Chicken liver, fried
Chicken liver boiled, stewed
6 Chicken heart stew
7 Oysters baked
16.4 mg ten Beef kidneys boiled, stewed
In 100 g:
6.7 mg
6.4-6.5 mg
5.8 mg
„ ^ , Goose or duck liver pate, canned foie 12.9 mg eleven 5.5 mg
gras
11.6 mg 12 Beef light stew, boiled 5.4 mg
9.03 mg 13 Chicken gizzards stewed, boiled 3.2 mg
7.2 mg fourteen Lean beef cooked any way 3 mg
Fish such as halibut, haddock, perch, salmon and tuna are not included in the rankings, but are ranked first in the seafood category. Many organ meats also deserve a place in the diet.
15 plant foods with the highest iron content [4]
Journal.edaplus.info - ■ Журнал здорового питания и диетологии
No. Products In 100 g: No. Products In 100 g
one Dried thyme (thyme) 123.6 mg eight Spirulina, dry powder 28.5 mg
2 dry basil 89.8 mg 9 dried parsley 22 mg
3 Turmeric 55 mg ten paprika (powder) 21 mg
four dried dill 48.8 mg eleven rice bran 18.5 mg
5 Dried cilantro (coriander) 42.5 mg 12 soy protein isolate 14.5 mg
6 Oregano (dried oregano) 36.8 mg 13 Dark chocolate, 70-85% cocoa 11.9 mg
7 Rice, wheat puffed 31.7 mg fourteen Pumpkin seeds 8.8 mg
See also Top 100 Natural Sources of Iron .
As for cereals, they do not lead the list. The highest percentage of the substance in amaranth, oatmeal, quinoa, spelled, barley groats. Legumes (soybeans, lentils, beans, mung beans ), cashews, unroasted sesame seeds, flax seeds, sunflower seeds, hazelnuts, dark green leafy vegetables (spinach and cabbage), dried fruits (raisins and dried apricots) also help increase iron intake.
Daily iron intake: recommended dose for the prevention of iron deficiency
Iron requirements are most stable in men. In women, they change depending on age and whether they are pregnant or breastfeeding. [5]
Norms of iron intake per day
Life period Age Men (mg) Women (mg)
babies 0-6 months 0.27 0.27
babies 7-12 months eleven eleven
Children 1 -3 years 7 7
Children 4-8 years ten ten
Children 9-13 years old eight eight
Teenagers 14-18 years old eleven fifteen
adults 19-50 years old eight eighteen
adults 51+ years old eight eight
The Tolerable Upper Intake Level without side effects is 45 mg per day for all men and women aged 14 years and older, and 40 mg for younger children. [6] Multivitamins often contain 18 mg of iron, and single-component supplements often contain up to 360% of the daily value.
Journal.edaplus.info - Журнал здорового питания и диетологии The daily need for iron increases:
• for vegetarians, the norm is 1.8 times higher than in the table, since non-heme iron is poorly absorbed;
• in pregnant women - not less than 27 mg / day, because a deficiency leads to premature birth and IDA in newborns;
• during menstruation;
• in athletes; [7]
• for those on kidney dialysis;
• with attention deficit hyperactivity disorder (ADHD). [eight] Daily requirement is reduced:
• for women after menopause;
• during breastfeeding - after childbirth, the need decreases from 27 mg to 9-10 mg;
• with regular blood transfusions.
Useful properties of iron
The trace element supports many important functions, including the functioning of the gastrointestinal tract and the immune system. Its benefits often go unnoticed until a person is faced with a deficiency.
The role of iron in the body and its health benefits:
• necessary for the formation of red blood cells;
• is part of more than 70 enzymes involved in the respiration of cells and tissues;
• supports physical growth and neurological development, especially in children under one year old;
• is part of myoglobin - a protein in the muscles that stores oxygen and is used during physical exertion;
• improves sports performance (some experts advise athletes to add 10 mg to the daily allowance);
• reduces fatigue - is crucial for physical and mental performance;
• participates in the metabolism and synthesis of thyroid hormones. [9]
The interaction of iron with other trace elements
Iron absorption does not occur on its own and requires the participation of cofactors :
• in the body there should be a protein level of at least 73-75 g / l, since ferritin and hemoglobin are protein complexes;
• cofactors are needed to promote its absorption - vitamin C, a group of vitamins B, copper, manganese. [ten]
Without creating such conditions, any dietary supplements and medicines can be useless. Vitamin C is especially important - in one study, taking 100 mg with meals increased iron absorption by 67%. [11, 12] Beta-carotene, the red-orange pigment of vegetables and fruits, is converted in the body to vitamin A. According to the study, it increases iron absorption by more than 300% for rice and 180% for wheat, corn. [13]
A large amount of calcium interferes with the absorption of iron. Just 165 mg of calcium from milk, cheese, or supplements reduces calcium absorption by 50-60%. [14, 15]
How to Increase Iron Absorption: Good and Bad Food Combinations
Foods that help you absorb more iron:
• any food with ascorbic acid: citrus fruits, dark green leafy vegetables, bell peppers;
• sources of beta-carotene and vitamin A: carrots , sweet potatoes (sweet potatoes), spinach, cabbage, zucchini, red peppers, melons, apricots, oranges, peaches;
• meat, fish, and poultry not only contain highly absorbable heme iron, but also stimulate the absorption of the non- heme form—1 g of meat, fish, or poultry has a boosting effect similar to that of 1 mg of vitamin C. [16]
Impair iron absorption
• dairy products due to calcium content;
• polyphenols in cereals, legumes, spinach;
• tannins in coffee, tea, wine and some berries; [17]
• phosphates in carbonated drinks;
• phytic acid ( phytates ), found in whole grains, cereals, soybeans, nuts, legumes.
negative effect of phytates can be counteracted by eating iron-rich foods with vitamin C and meat at the same time. As for drinks, drinking a cup of black tea with meals reduces iron absorption by 6070%, regardless of its strength. If you drink it between meals, the negative effect is reduced to 20%.
How to keep iron in foods during cooking?
The mineral is relatively thermally stable. It is very simple to increase its content in food and assimilation:
• you need to soak cereals, legumes for several hours before cooking to reduce the concentration of phytic acid;
• it is enough to cook dishes in cast-iron pots - dishes increase the iron content by 5 times;
• it is important to cook food for the minimum amount of time necessary for safe consumption.
[eighteen]
The use of iron in medicine: when is it prescribed and in what forms
Studies show that about 80% of people in the world do not receive the substance and 30% suffer from IDA. For the treatment and prevention of anemia, drugs are used, vitamin and mineral complexes with iron salts, such as fumarate , gluconate, sulfate. They are produced in the form of tablets, capsules, liquids. The most digestible and close to the body form of the mineral is chelated. [19]
Intravenous formulations are indicated when oral supplements are ineffective or cannot be used. For example, they are prescribed to patients with inflammatory bowel disease (IBD) - Crohn's disease, ulcerative colitis. [20, 21]
Iron medicines can cause side effects:
• constipation,
• abdominal pain,
• diarrhea
• nausea,
• staining of teeth. [22]
Dietary supplements that are made from plant materials are less likely to cause adverse reactions. Any mineral supplements are usually taken during or immediately after a meal at the same time. There should be a maximum time interval between their intake and tea, coffee, nuts, dairy products.
Iron in scientific research: what scientists say about the trace element
A study published in 2021 found that serum iron levels are correlated with development in 4-7 year olds. With its shortage, kids have lower grades, are passive. [23] Scientists have also found that people with gastritis caused by Helicobacter often suffer from anemia. pylori , celiac disease and heart failure.
Anemia is also a common complication of chronic kidney disease. In response to iron deficiency, the body absorbs lead, cadmium and aluminum, which adversely affects the bone and central nervous system.
Contraindications and possible complications
Pregnant women, children under one year of age, athletes and adolescent girls are at the greatest risk of IDA. Vegetarians and vegans are also prone to the disease due to the fact that non-heme is less digestible. [24, 25, 26]
Most often, anemia occurs in a mild form. If left untreated, it will lead to health problems:
• heart failure or an increase in heart muscle, as the heart needs to compensate for the lack of oxygen and pump more blood;
• deterioration in concentration, mental activity;
• premature birth in pregnant women;
• low body weight in newborns;
• reduced immunity, stunted growth and development - deficiency in early childhood is associated with lower IQ. [27, 28]
Iron overload is caused by repeated blood transfusions, large doses of supplements, and rare metabolic disorders. For example, hemochromatosis is a disease in which the absorption of a component is enhanced. [29] Excessive accumulation of the micronutrient is dangerous because it provokes liver damage, the development of diabetes, heart disease and certain types of cancer. [30, 31, 32, 33]
Iron deficiency symptoms:
• fast fatiguability;
• pale skin and nails, lack of holes on the nails;
• dizziness;
• headache;
• decrease in endurance;
• sensitivity to cold;
• shortness of breath with little physical exertion;
• increased irritability;
• loss of attention;
• hair loss - slight or excessive, similar to genetic male and female pattern baldness. [34] Signs of excess iron
Iron poisoning from food sources is rare, and symptoms of excess iron occur in 1 in 4 people:
• high blood sugar;
• weakness;
• abdominal pain;
• hyperpigmentation or bronze skin color;
• loss of sexual desire;
• reduction in the size of the testicles in men;
• decrease or absence of menstruation in women. [35]
The problem can lead to frequent supplementation - more than 20 mg of the substance at a time. [36] The interaction of iron with drugs
Some medications can deplete mineral reserves, reduce its absorption:
• quinolones - a family of antibiotics that includes ciprofloxacin and levofloxacin ;
• tetracycline;
• proton pump inhibitors for the treatment of gastric reflux - ranitidine , omeprazole , nolpaza, etc.; [37]
• angiotensin- converting enzyme (ACE) inhibitors for high blood pressure;
• bile acid sequestrants to lower cholesterol - colestipol , cholestyramine .
Iron supplements, in turn, reduce the bioavailability levodopa, which is prescribed to treat restless legs syndrome, Parkinson's disease. They also impair the absorption of levothyroxine , a drug used to treat a poorly functioning thyroid gland. [38]
Expert comment
Tatyana Eliseeva, nutritionist, nutritionist
It is advisable to get your daily iron intake from wholesome foods, not from supplements. A healthy diet has no risk of overdose and fills the body with other nutrients. It is also advisable not to drink tea after meals, cook in cast iron cookware, and eat foods high in iron and vitamin C at the same time. If changes in diet do not improve performance, then it is worth talking with a doctor, dietitian or nutritionist about taking supplements.
In summary, iron deficiency is one of the most common nutritional problems in the world. Its absorption depends on how much the substance accumulates in the body. This is a good reason to monitor the level of ferritin and seeks to prevent the problem, rather than deal with the consequences.
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An extended HTML version of this article is available on the edaplus.info website. Iron for the Body - Top 30 Sources and Health Importance
Eliseeva Tatyana, editor-in-chief of the project EdaPlus.info E-mail: eliseeva.t@edaplus.info
Received 21.12.2021
Abstract. The article discusses the main properties of iron ( Fe ) and its effect on the human body. A systematic review of modern specialized literature and relevant scientific data was carried out. The best natural sources of iron are indicated . The use of the mineral in various types of medicine and the effectiveness of its use in various diseases are considered. The potentially adverse effects of iron on the human body under certain medical conditions and diseases are analyzed separately.
