Iron is an important component of hemoglobin, myoglobin and a variety of enzymes, and is indispensable for a variety of physiological reactions, including oxygen, energy production, DNA replication and repair.Note 8
At the same time, iron also plays an important role in the development of central nervous system, immunity, endocrine, cardiovascular, brain and other systems. Although the most common, it is also one of the most commonly deficient nutrients.
Iron in food is usually present in two forms:
Heme iron: This type of iron is found in animal foods (mostly red meat) and is highly absorbed by the body (about 15–35%), several times that of non-heme iron.
Non-heme iron: This type of iron is the most common type of food, found in both animal and plant foods.
What are the recommended scientifically proven benefits of iron?
Iron deficiency anemia
Iron deficiency anemia, as the name suggests, is a disease caused by iron deficiency, without enough iron, the body can not produce hemoglobin, and produce abnormal red blood cells, the efficiency of carrying oxygen becomes low (common symptoms are extreme tiredness, shortness of breath, bloodless face, cold hands and feet, cracked nails, etc.)
Iron deficiency anaemia is prevalent in about 30% of the global population, with infants and young children being the most common. This is followed by non-pregnant adult women, where menstrual blood loss and pregnancy-related iron loss are the biggest causes. In addition, a common cause in men and postmenopausal women is occult gastrointestinal bleeding.
Treatment for iron deficiency anemia generally starts with a diet and consumes iron-rich foods such as red meat, legumes, and green plants.Note 1
If iron stores and haemoglobin cannot be restored to normal levels by diet alone, or if anaemia is too severe, iron is one of the treatment options.
In addition, the choice of treatment depends on urgency and the patient’s clinical symptoms, and if hemoglobin is less than 8 g/dl with signs of tachypnea, severe fatigue, or myocardial ischemia, immediate transfusion is necessary.
Postpartum depression occurs between 13% and 19% (usually after 1 month postpartum) and is the most common psychological illness faced by women after childbirth (hormonal fluctuations and sleep changes are the biggest causes).
The main symptoms are low mood for more than 2 weeks, accompanied by intense sadness, loss of self-worth and lack of hope for life.
A double-blind controlled study (6 weeks, 70 postpartum mothers) found that iron supplementation not only increased ferritin stores, but also had a more significant effect on post-depression by 42.8%, compared with 20% in the placebo group.Note 2
In addition, compared with the improved subjects, the ferritin of those with persistent depression was significantly lower, and the iron deficiency rate reached 27.1%, compared with 4.5% of the improved subjects.
Migraine in children
Migraine is a common type of headache in children, with an estimated incidence of about 5% in children between the ages of 15 and 10. In general, if the incidence of migraine occurs more than 3 to 4 times a month and it seriously interferes with daily routine, you should consider seeking medical attention.
A controlled study (3-month, 98 children aged 5 to 15 years) found that children with iron deficiency increased migraine frequency, severity, and disability scores.Note 3
The combination of iron and the drug topiramate helped reduce the frequency, severity, and duration of attacks and paediatric migraine disability assessments.
Children’s intellectual development
Prenatal nutritional imbalances have an important impact on fetal development and may cause underweight in the short term, resulting in developmental delays and increased neonatal mortality.
In the long run, it will affect the subsequent development of metabolic phenotypes and increase the incidence of a variety of chronic diseases (such as: type 2 diabetes, hyperlipidemia, hypertension, coronary heart disease).Note 5
A generational study (Cohort Study (sample size of 676 children aged 7 to 9 years) found that prenatal nutritional supplementation (iron and folic acid) in pregnant women was significantly positively correlated with young children’s intellectual development, working memory, inhibitory control, and motor function (high rates of iron deficiency in the tracked areas).Note 4
Attention deficit hyperactivity disorder (ADHD)
ADHD is a neurodevelopment-related disorder commonly seen in school-age children, with symptoms of extreme hyperactivity, impulsivity and inattention, with a prevalence of about 5% to 15%, often affecting the patient’s family relationships and schoolwork.
Due to the complex causes of the disease, there is currently no complete theory to explain, but known causative factors include
maternal smoking and stress, alcohol, drug abuse, chemicals, heavy metals, artificial food coloring, low birth weight, and preterm birth.
A controlled study (12-week study of 23 children with ADHD without anaemia) found that iron supplementation helped reduce ADHD scores (compared with placebo).Note 6
However, another systematic review (11 randomized controlled trials) found that there is no significant evidence to improve ADHD in children, whether it is iron, zinc and magnesium.Note 7
What are the side effects of iron supplementation?
Although iron is relatively safe at normal recommended doses, some immediate side effects have been reported, mostly related to gastrointestinal discomfort, such as nausea, vomiting, heartburn, diarrhea, constipation, and darkening of stools.
Most of these gastrointestinal discomforts are related to fasting ingestion, so taking them with meals can help reduce the occurrence of such conditions.
For people without specific medical conditions, the maximum tolerable intake of iron is approximately 45 mg/day and is suitable for adolescents and adults (including pregnant and nursing women) aged 14 to 18 years.
As for short-term taking large doses of iron, it may cause acute poisoning, abdominal pain, melena, pulse, low blood pressure, fever, dyspnea, coma and other symptoms (if the dose exceeds 20-60 mg/kg in a short period of time, poisoning symptoms may occur).
If iron poisoning is not immediately fatal, symptoms usually resolve within 24 hours. However, it may reappear within 12 to 48 hours after ingestion, resulting in multiple organ failures such as cardiovascular, liver, kidney, blood, central nervous system, and even long-term damage.
Safety precautions for iron supplementation
- Do not take iron supplements unless a blood test shows iron deficiency
- People with hereditary hemochromatosis or other conditions (eg, liver disease) that cause iron overload may develop various adverse effects of iron toxicity at the lowest tolerable intake (45 mg/day).
- Taking vitamin C increases iron absorption, and if you consume more than several grams of vitamin C a day and combine iron with iron, it will increase the risk of iron poisoning
- Iron supplementation may reduce absorption of certain drugs, such as levodopa, levothyroxine, penicillamine, antibiotics, and ACE-inhibitors. Conversely, drugs may also inhibit iron absorption, so be used separately (preferably more than 2 hours apart) for safety
- If you have poor liver and kidney function or have special medical conditions, please discuss with your doctor before use
- Although there is insufficient evidence, observational studies have found that high levels of iron in the body may be associated with cancer, cardiovascular disease, and diabetes