If you are concerned that you may not be receiving all of the vitamins and minerals you need from your current diet, you may be considering taking a multivitamin or dietary supplement.

When trying to decide which supplement to take, you will no doubt come across some multivitamins that contain iron and others that do not. While iron is an essential mineral that our bodies need in order to function, it can be dangerous at high levels, leaving many people to wonder if it is better to take a multivitamin without iron.

What is iron?

Iron is an essential mineral that exists naturally in two forms: heme iron and nonheme iron. The body needs both heme and nonheme forms of iron to function properly, but about 95 percent of functional iron in the body is heme iron. The body is better able to absorb heme iron from the foods that we eat, while it is less efficient at absorbing nonheme iron. Heme iron is found only in animal products, including meat, while sources of nonheme iron include plants, animal products, and foods that are fortified with iron, such as cereals. Heme can consist of up to two thirds of the average person’s intake of iron in countries that eat large amounts of animal products, particularly meat. 

Why do we need iron?

The body relies on iron in order to perform many essential functions, and iron deficiency can cause serious problems. Iron is used by the body in order to properly develop and grow, so it is particularly important during childhood and for women who are pregnant or lactating. The body uses iron for the production of hemoglobin, which is a protein that delivers oxygen from the lungs to various parts of the body via the red blood cells. Myoglobin, another protein that is needed in order to deliver oxygen to the muscles, is also produced with the help of iron. Iron is also used for the production of several hormones in the body, so iron deficiencies or surpluses can contribute to hormonal imbalances. Therefore, ensuring that people receive the right amount of iron is critical. Most people receive an adequate amount of iron from the food that they eat, but deficiencies are also common. People with an iron deficiency may need to take an iron supplement. 

What is the recommended daily intake for iron?

The Food and Nutrition Board at the Institute of Medicine determines the recommended dietary allowances for all vitamins and minerals, including iron, based on a person’s age, sex, and whether they are pregnant or lactating. The recommended dietary allowance for iron, as defined by the Food and Nutrition Board, is considered sufficient to meet the needs of about 97 to 98 percent of health individuals. However, people with certain medical conditions may need to take in more or less iron in order to meet their body’s specific requirements. The recommended dietary allowance for iron is shown below.

As reflected in the above table, the iron consumption needs for women are higher than those of men during childbearing years.

What are the symptoms of iron deficiency?

Many people around the world suffer from a mild version of Iron deficiency, but most people with mild iron deficiency do not know that they are impacted by the condition. Mild iron deficiency generally does not cause symptoms, but over time, a chronic deficiency can lead to a condition called iron deficiency anemia.  Iron deficiency anemia occurs when the body is unable to produce enough red blood cells to deliver oxygen to the extremities, organs, and muscles. The following symptoms are common when experiencing low levels of iron and iron deficiency anemia:

• Tiredness
• Shortness of breath
• Hearing ringing, buzzing, or hissing sounds in your head
• A sore tongue or difficulty swallowing
• Itchiness
• Changes in the way food tastes
• Cravings for non-food items, such as dirt (also known as pica)
• Spoon-shaped nails
• An uncontrollable urge to move your legs, or restless leg syndrome
• More frequent bouts of illness
• Lack of energy
• Difficulty concentrating
• Difficulty regulating the body temperature or frequently feeling cold
• Pale skin
• Headaches
• Heart palpitations
• Hair loss
• Painful open sores in the corners of the mouth

Some of the symptoms listed above may occur when a person has low levels of iron, but other people may not experience any symptoms until the condition has progressed to iron deficiency anemia. People who are prone to iron deficiency should have their iron levels checked regularly to ensure that they receive adequate amounts of dietary iron from natural sources. If diet alone is enough to provide an adequate supply of iron, iron supplements may be required. 

What are some natural sources of iron?

Iron is found naturally in a wide variety of different foods, including both plant and animal products. As a result, most people receive plenty of iron from their diets. Natural sources of iron include lean meat, seafood, nuts, beans, and vegetables, and iron can also be found in fortified grain products. The average American receives about half of their dietary iron intake from grain products that have been fortified with iron. Excellent sources of iron include:

• Kidney beans
• Sardines
• Chickpeas
• Dark chocolate
• Beef liver
• Beef
• Potatoes
• Lentils
• Fortified breakfast cereals
• Oysters
• White beans
• Spinach
• Tofu
• Tomatoes
• Cashew nuts

Is it better to take a multivitamin without iron?

After learning about iron deficiency, it might seem like ingesting more iron, rather than less, would be beneficial. However, it is possible to take too much iron, and the most common mechanism by which this occurs is through unnecessary iron supplementation. Taking too much iron can cause common side effects like changes to stool, nausea, constipation, vomiting, and abdominal pain. However, people usually do not experience negative effects as a result of eating too much iron in natural foods. This is because the body naturally regulates the absorption of iron from food as it passes through the intestines. However, the body struggles to regulate the absorption of iron from dietary supplements in the same way, because the intestines cannot block the buildup of excess amounts of iron from supplements. As a result, it is better to take a multivitamin that does not contain iron if you need to address nutritional gaps, because taking a vitamin that includes iron can be dangerous if you are not deficient. It is recommended that people check their iron levels with their doctors prior to taking an iron supplement in order to ensure that they do not receive too much of the mineral. Unfortunately, taking too much iron can be detrimental.

What are the risks of taking too much iron?

There are numerous risks associated with taking too much iron. The body’s ability to absorb zinc is impacted when high doses of iron are received; diminishing the body’s ability to absorb zinc can cause a nutritional deficiency. The risks associated with iron intake increase as the dose becomes higher. When taken at extremely high doses in proportion to body weight, excess iron can cause convulsions, organ failure, coma, and even death. Hemochromatosis, a genetic disorder that causes iron to build up in the body at toxic levels, increases the likelihood of iron poisoning, but it can happen to anyone. People who suffer from hemochromatosis can develop liver cancer, heart disease, and cirrhosis of the liver, and heart disease as a result of their condition. Iron poisoning is a dangerous condition that can happen to anyone, regardless of whether or not they suffer from hemochromatosis.

What are the symptoms of iron poisoning?

Iron poisoning was the leading cause of medication overdose death among children under the age of 6 in America, and although it is on the decline, it is still a serious problem. Anyone can experience iron poisoning as a result of consuming too much iron through supplements, however. The first symptoms of iron poisoning, which typically develop within the first six hours, include:

• Nausea
• Abdominal pain
• Vomiting blood
• Diarrhea
• Dehydration
• Black or bloody stools

Often, these symptoms seem to approve for about 24 hours, but serious complications often reappear within 48 hours of overdose. These include:

• Dizziness
• Headache
• Shortness of breath and fluid in the lungs
• Jaundice (yellowing of the skin due to liver damage)
• Low blood pressure
• Fast or weak pulse
• Fever
• Grayish or bluish color in the skin
• Seizures

 Iron poisoning typically occurs when doses higher than 35 mg per kg of bodyweight are taken by children and doses higher than 20 mg per kg of body weight is taken by adults. 

Sources:

https://www.healthline.com/health/iron-poisoning 

https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/ 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3967179/ 

https://www.healthline.com/nutrition/iron-supplements