Side effects when taking iron you need to be aware of

11.04.23 120

Although it has many important uses for the body, iron supplementation in the wrong way can cause a series of health complications. What are the side effects of taking iron? What is the truth of taking iron tablets that cause nausea? Invite readers to answer the above questions through the following article of Solife.

1. What is Iron?

Iron (Fe) is a trace element necessary for the vital functioning of the body. Iron can be found in red blood cells (hemoglobin) – the main component of blood, also known as hemoglobin. Small amounts of iron are also found in intracellular enzymes such as catalase, peroxidase and cytochrome. But these enzymes all play an important role in the redox processes of the cell.

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In addition, iron can easily be found in your daily diet. Some common foods that contain iron include: red meat, fish, seafood, vegetables, and animal organs. Iron can be absorbed through the stomach and small intestine, then it will be absorbed into the blood and go to different organs. 

Read more: What is the function of iron? Is it fine to take iron and vitamin c at the same time

2. Benefits of iron supplementation for the body

Iron is essential for physiological and biochemical activities of the body, such as:

  • Treatment of blood diseases: One of the most common effects of iron is the production of abundant and healthy red blood cells. The cause of anemia is usually due to a disorder in the absorption of iron, leading to an inadequate amount of red blood cells in the body and causing anemia. Anemic people will have pale skin, the body is often exhausted, tired, dizzy and nauseated. Prolonged anemia can lead to a more serious disease than leukaemia.
  • Improves cognition: acts as an oxygen carrier, iron helps carry oxygen throughout different organs in the body, including the brain. In the course of daily activities, many interesting medical studies have shown that thinking, thinking and perceiving are the activities that consume the most oxygen. Therefore, without enough iron to regularly transport oxygen to the brain, it will be difficult for us to think clearly. At the same time, the ability to concentrate, think logically, and critically will be reduced.
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  • Improves Mood: Dopamine is a neurotransmitter and a happy hormone. The synthesis and maintenance of the right amount of dopamine for the body requires a lot of different “materials”, including iron. Adequate iron supplementation can help trigger dopamine synthesis and, in turn, improve our mood to some extent.
  • Strengthens immunity: iron deficiency will delay the ability to regenerate a wide range of immune cells, including white blood cells and T-lymphocytes. 
  • Good for pregnancy: during pregnancy, the mother’s body will use a lot of red blood cells to be able to maintain the amount of oxygen for both mother and baby. Iron deficiency will seriously affect pregnancy, increasing the risk of premature birth, low birth weight, infections in the mother and slow brain growth in the baby. 

It can be seen that iron supplementation is always a matter of concern. In addition to the amount of iron consumed through daily meals, iron can also be supplemented through different forms of functional foods. However, it should be noted that excessive consumption will cause side effects when taking iron. 

Read more: The side effects of vitamin C you may encounter

3. Side effects when taking iron

A few side effects when taking iron tablets have been reported, including immediate symptoms after use and long-term sequelae such as: 

  • Related to the digestive system: constipation, diarrhea, abnormal bowel movements or loss of appetite, indigestion. 
  • Immune system related: some negative immune response symptoms may appear such as hives, itching, red rash, nausea, mouth swelling or difficulty breathing
  • Damage to liver function due to excess iron, oxidation in the liver takes place faster than normal, tendon damage to liver cells. 
  • Changes in skin pigmentation: excess iron in the blood will be transferred to the epidermal cells, thereby making the skin dark. 
  • Causes neurological syndromes such as excitability, anxiety, Parkinson’s, ADHD and Alzheimer’s.
  • Ovarian damage with some unusual manifestations such as menstrual disorders, delayed puberty.
Những tác dụng phụ khi uống sắt có thể gặp phải
  • Diabetes: The long-term accumulation of iron in organs such as the pancreas can interfere with the synthesis of insulin – the hormone that metabolizes blood sugar. 

Although it plays many important roles in the body, the side effects when taking iron are a matter of concern. Users need to adhere to the recommended dosage when using iron supplements for a long time. In particular, it is necessary to go to the medical center for timely examination if any health abnormalities are detected while taking iron supplements. 

4. When taking iron you need to note these things

Here are a few notes so that readers can use iron supplements more effectively, avoiding reducing the body’s iron absorption efficiency or causing side effects when taking iron. 

First, it is necessary to mention the time of iron supplementation for the body. Specifically, iron tablets can work best when taken about 1-2 hours after eating. When taking iron, you need to drink more water and do not chew the medicine (if it is in the form of oral tablets). 

Some foods can interfere with the body’s absorption and metabolism of iron, such as tea, coffee, alcohol, bread, soy protein. In addition, iron pills may cause some cross-reactivity with antibiotics, thyroid medications, or anticonvulsants. It is necessary to consult a doctor or nutritionist if you are taking a combination of one or more different medicines while taking iron tablets. 

Finally, several other essential micronutrients are counterproductive to iron absorption. Avoid taking calcium, vitamin C and iron together to limit the side effects between these compounds.

In addition, it is necessary to pay attention to choosing reputable functional food brands to always have the assurance of drug composition and quality. 


Through the above article, Solife has mentioned the uses, usage and important notes to avoid side effects when taking iron tablets. Hopefully, readers have gained new knowledge, avoided the situation of “losing money” and choosing functional foods that are suitable for their needs and health status.


Trần Hoàng Uyên (Senior Manager Pharmaceutical company) là chuyên gia cấp cao với nhiều năm kinh nghiệm trong lĩnh vực dược phẩm. Tốt nghiệp cử nhân chuyên ngành Quản lý dược I tại Trường Đại học Y dược TP. Hồ Chí Minh và hiện đang công tác tại công ty dược phẩm. Với hơn 10 năm kinh nghiệm làm việc trong ngành dược, chị Hoàng Uyên là chuyên gia cộng tác tham vấn y khoa cho danh mục blog cũng như các nội dung liên quan trên Solife. (Tran Hoang Uyen (Senior Manager Pharmaceutical company) is a senior specialist with many years of experience in the Pharmaceutical field. She graduated Bachelor of Pharmacy Management I at the University of Medicine and Pharmacy at Ho Chi Minh City and is currently working for a pharmaceutical company. With more than 10 years of experience working in the pharmaceutical industry, Ms. Hoang Uyen is a medical consultant collaborator for content on Solife's website.)