Iron - Requirement and absorption of the essential mineral

Iron is an essential component of hemoglobin, myoglobin, and ferritin, playing a vital role in oxygen and electron transport. It is involved in DNA synthesis, cellular respiration, fatty acid desaturation, hydrogen peroxide degradation, tyrosine iodination, prostaglandin biosynthesis, tryptophan catabolism, liver detoxification, and immune modulation. Unfortunately, modern diets high in sugars and fats fail to provide adequate iron levels. Other causes of iron deficiency include disorders affecting absorption, such as celiac disease (gluten intolerance) or Crohn's disease. Symptoms of iron deficiency encompass weakened immunity, apathy, chronic fatigue, pale skin, brittle nails and hair, as well as difficulties with concentration, memory, and learning.

Boys aged 9 to 13 years require approximately 11 mg of iron per day. However, women are most affected by iron deficiency, as they consume less red meat – the primary source of iron – follow restrictive diets more often, and experience blood loss during menstruation. Girls in this age group should intake 8 mg of iron daily.

The human body requires iron for proper functioning, which can be obtained from both animal and plant-based foods. While plant-based foods often contain higher amounts of iron per unit weight, the iron present in meat and offal is in a form that is significantly more bioavailable. The richest sources of iron include: dried yeast – 20 mg/100 g, liver – 7.5 – 17 mg/100 g, wheat bran – 12.9 mg/100 g, beef – 1.3 – 3.1 mg/100 g. Iron poisoning through food consumption is practically impossible, but there is a risk of excessive intake when using dietary supplements and fortified products. In addition to the form of iron, other factors also influence its bioavailability, such as drinking tea during meals, which can inhibit absorption, while adding lemon juice enhances it.

This chemical element is predominantly found in nature in the form of various compounds, exhibiting diverse chemical properties. Apart from its role in living organisms, its presence in carbon alloys, i.e., steel, is of critical importance. Steel serves as the primary material in the global metallurgical sector. Iron constitutes approximately 35% of the total mass of all elements on Earth.

Food category with iron content per 100 grams: beef, veal, lamb, goose, duck, rabbit, 2,6 mg, 2,4 mg, 4,7 mg, 2,5 mg, 2,4 mg, 3,2 mg, meat products: pork liver, beef liver, veal liver, poultry liver, 18,7 mg, 9,7 mg, 7,4 mg, 9,5 mg, fish: salmon, herring, smoked cod, smoked mackerel, sardines in oil, tuna in water, 1 mg, 1 mg, 1,2 mg, 2,9 mg, 1,2 mg, eggs: egg (70 g), 1,4 mg, cereal products: rye bread, whole grain bread, pumpernickel, graham crackers, wheat bran, oat flakes, barley, buckwheat, brown rice (1 slice), 1,1 mg, 1,3 mg, 1,3 mg, 1,1 mg, 10,5 mg, 4,2 mg, 4,8 mg, 2,8 mg, 1,9 mg, 1,3 mg, seeds and kernels: pumpkin seeds, sunflower seeds, sesame seeds, poppy seeds, 15 mg, 4,2 mg, 14,5 mg, 9,7 mg, nuts: pistachios, hazelnuts, peanuts, almonds, 6,7 mg, 3,4 mg, 3,2 mg, 3,1 mg, vegetables: lentils, broccoli, Brussels sprouts, beetroot, chicory, garlic, asparagus beans, green peas, kohlrabi, dill, parsley (leaves and root), dandelion, sorrel, chives, spinach, 1,9 mg, 2,4 mg, 0,9 mg, 1,7 mg, 0,9 mg, 1,7 mg, 1,1 mg, 2 mg, 0,4 mg, 6,5 mg, 1,1 mg, 2,1 mg, 2,4 mg, 1,6 mg, 1,8 mg, fruits: blackcurrants, whitecurrants, redcurrants, raspberries, avocado, 1,2 mg, 1 mg, 1 mg, 0,6 mg, 0,6 mg, dried fruits: apricots, prunes, figs, dates, raisins, 3,6 mg, 0,9 mg, 3,3 mg, 2 mg, 0,9 mg, legumes: beans, red lentils, soybeans, 6,9 mg, 5,8 mg, 8,9 mg.

Iron in food exists in a trivalent form, but in the stomach, it is converted into divalent iron, which, when bound to proteins, forms ferritin – a readily absorbable compound. However, the human body can only absorb around 10% of dietary iron, and even less from plant-based sources. To counteract iron deficiency, several key steps must be taken: reducing the intake of strong tea and coffee in favor of weaker alternatives or juices, as caffeine significantly inhibits iron absorption. Additionally, it is important to note that calcium can impair iron uptake, so one should avoid consuming calcium- and iron-rich foods together, though calcium should not be entirely eliminated from the diet, especially in children, as it is crucial for bone development. Increasing the consumption of foods rich in vitamins B12, B6, C, E, folic acid, copper, zinc, and molybdenum can enhance iron absorption. When supplementing, iron tablets should be taken with vitamin C-rich juices to improve bioavailability. The best sources of iron are animal-based products such as liver and red meat. Iron excess is rare but can lead to serious health issues, including hormonal imbalances, abdominal pain, joint pain, osteoporosis, depression, and heart disease. Iron is an essential micronutrient, so monitoring its levels along with ferritin and blood morphology is advisable. Iron deficiency is common in developing countries but also prevalent in developed nations, where imbalanced diets (vegan, restrictive) and unhealthy lifestyles (overwork, overtraining) contribute to deficiencies. Therefore, a balanced diet rich in high-quality meat products, which provide essential macronutrients, is recommended. Given that daily iron requirements are increasing and that a diet high in refined fats and simple carbohydrates, combined with excessive coffee consumption and smoking, lowers iron levels, this negatively impacts cognitive performance.