Iron is a common mineral that helps reduce fatigue, depression and help restore balance to the blood stream. Iron supplementation is fairly common, particularly among women. You can find iron naturally in many different foods such as red meat, poultry, fish, lentils, chickpeas, and often you will find that breakfast cereals are fortified with iron.
Supplements are often made from either Iron (II) fumarate or Iron (II) sulfate. Both are excellent supplement ingredients and are easily absorbed by the body (1).
Most people get all the iron that they need through diet, as such there is little benefit to supplementing with iron. In fact, the only reason you would need to would be if you were at risk of being deficient in iron. This is actually quite common though, which is why iron supplementation is fairly normal.
In this article we are going to look at the benefits of iron supplementation, potential side effects, the recommended dosage, before recapping what we’ve learned about iron.
1Iron supplementation may help reduce fatigue symptoms. While there aren’t many benefits to iron supplementation in people who are not anemic (suffering from an iron deficiency) there does appear to be some evidence that iron supplementation can reduce fatigue.
A 2003 study in the British Medical Journal found that non-anemic women who suffered from unexplained fatigue found an improvement in symptoms after taking iron (2) .
The study found that a lot of the women who saw an improvement had low levels of ferritin (an intracellular protein that stores and releases iron in the body).
A similar study in 2012 by Vaucher et al also found that women who had low ferritin levels and unexplained fatigue may benefit from iron supplementation, the study indicated that six weeks of supplementation were sufficient to see an improvement (3).
While the women were not anemic, having low levels of ferritin is a common cause of iron deficiency anemia (4).
2Iron supplementation may also reduce the risk of depression. A 2017 meta analysis in the journal of Psychiatry Research looked at dietary zinc and iron intake and its effect on the risk of depression. The meta analysis found that there was a link and that taking iron supplements (as well as zinc) may help reduce depression risk (5).
A similar study in 2007 in the European Journal of Clincal Nutrition found that there was a relationship between depression and serum ferritin levels. As with fatigue, it would appear that taking iron supplements would help to reduce depression risk (6) .
If ferritin levels of low, it would take a larger dose of iron to meet dietary requirements – making it more difficult to get enough iron through diet alone.
3Iron supplementation may help prevent hair loss. One of the side effects of iron deficiency anaemia is hair loss (7).
If this is the case then supplementation with iron can prevent it. Sadly there are many causes of hair loss, and iron supplementation cannot treat any of them except for the iron deficiency induced version.
A study in the British Journal of Dermatology found that there was no association with low serum ferritin and chronic diffuse telogen hair loss (8).
This means that regular hair loss is unaffected. However, if your hair loss is due to iron deficiency anemia then taking an iron supplement could help treat it.
A study in the Journal of the American Academy of Dermatology (2006) states that while giving iron supplements to people with hair loss is not a good idea, screening people who are experiencing hair loss for an iron deficiency could be helpful (9).
4Iron supplementation may improve cognition in women/children who are iron deficient. A study in The Lancet (1996) by Bruner et al looked at the impact of iron supplementation in young girls who are iron deficient (10).
The study screened 716 adolescent girls for non-anemic iron deficiency, out of those 716 girls 81 were found to have non-anemic iron deficiency. Participants were either offered 650mg of Iron Sulphate twice per day, or a placebo.
Next, the girls performed four tests that measured attention and memory. The girls who received Iron Sulphate performed better in both verbal learning and memory compared to the placebo group. A 2014 study in Neuropsychiatric Disease & Treatment re-examined the subject (11).
The study noted that “despite there being methodological differences among studies, there is some evidence that iron supplementation improves cognitive functions. Nethertheless, this must be confirmed by means of adequate follow-up studies among different groups”.
A 2004 study in Nutrition Reviews stated that “Undernutrition and deficiencies of iodine, iron, and folate are all important for the development of the brain and emergent cognitive functions” (12).
In other words, children should avoid deficiencies in iron while growing if they want optimal cognitive function as they age.
A study in Public Health Nutrition (2005) by Sachdev, Gera, and Nestel looked at the effect of iron supplementation on mental and motor development in children (13).
It found that iron supplementation has a modest effect on mental development scores. “This effect is particularly apparent for intelligence tests above 7 years of age and in initially anemic or iron-deficient anemic subjects”.
5Iron supplementation can reduce the risk of anemia in menstruating women. The most common use for iron supplementation is to reduce the risk of anemia in women who are menstruating. Teen girls and women with heavy periods are the most in need of iron supplementation (14).
A study on Danish women aged 18 to 30 found that moderate daily doses of iron supplementation could help prevent iron deficiency (15).
It stated that “preventative measures should be focused on those women whose menstruation lasts 5 days or longer, who have menstrual bleeding of strong intensity, who use IUD without gestagen, and who are blood donors”. (IUD stands for intrauterine devices).
Another study by Simon, Hunt, & Garry (1984) found that iron supplementation was beneficial to menstruating women who donated blood (16).
This was because iron supplementation helped maintain body iron stores and haemoglobin levels.
In a study looking at male and female blood donors in the Journal of the American Medical Association (JAMA) in 1981 “reduced iron stores were found in 8% of male and 23% of female donors. Menstruation significantly lowered iron stores in women” (17).
6Iron supplementation may help improve behavioral development in children. A study in 2000 by Grantham-McGreggor, Walker, & Chang looked at the effects of nutritional deficiencies in behavior (18).
They stated that “There is substantial evidence that reduced breast-feeding, small-for-gestational-age birth weight, Fe and I deficiency, and protein-energy malnutrition (PEM) are associated with long-term deficits in cognition and school achievement”.
Fe is the chemical name for Iron, and as stated a deficiency in iron may cause issues with behavior and cognition. There is not enough evidence that iron supplementation can improve behavioral development in children.
But this study was looking at women taking iron while pregnant, rather than supplementing the diet of children at risk of being iron deficient.
7Iron supplementation may reduce risk of infection in children who are anemic. The jury is still out with regards to the effect of iron supplementation on infection risk. It is known that having an iron deficiency can lead to a reduced ability to fight infection, but studies have failed to definitively say whether iron supplements can remedy this.
An article by Stephen Oppenheimer in The Journal of Nutrition (2001) gave an overview on current scientific thinking on the subject (20).
He mentioned two studies in particular that could point to iron having a positive effect on infection risk.
“Milk fortification reduced morbidity due to respiratory disease in two early studies in non malarious regions” and “one study in a non malarious area of Indonesia showed reduced infectious outcome after oral iron supplementation in anaemic schoolchildren”.
He also mentioned studies that did not find similar results, deciding that more research was needed before reaching a conclusion.
As with most vitamins and minerals, there isn’t particularly any side effects to taking the correct dosage of iron per day. But there can be issues about taking too much iron each day. In this section we will take a look at some of the common side effects of taking too much iron through supplementation.
1Iron Supplementation may increase the risk of developing diarrhea. A study in the British Medical Journal (2002) looked at 28 controlled trials on 7892 children 21.
The study was designed to find out whether iron supplementation could increase the incidence of infectious illnesses in children. It found that iron had no effect on infectious illnesses, but did slightly increase the risk of developing diarrhea.
But other studies have found contradictory results. A 2003 study in the Journal of Nutrition found that while a micronutrient mix supplement (containing iron) increased incidence of diarrhea in Bangladeshi children, a zinc and iron supplement significantly reduced incidence of diarrhea (22).
According to the National Institute of Health “acute intakes of more than 20mg/kg of iron from supplements or medicines can lead to gastric upset, constipation, nausea, abdominal pain, vomiting” it recommends taking food at the same time as taking any iron supplement as it can reduce the likelihood of these symptoms (23).
It also possibly explains why diarrhea incidence may increase with iron supplementation.
2Taking too much Iron through supplements can reduce zinc absorption. One of the potential causes of gastrointestinal upset is the fact that consuming too much iron can reduce zinc absorption and lead to a zinc deficiency (24).
A 1998 study in the American Journal of Clinical Nutrition looked at the interaction of iron and zinc in humans (25).
It found that although fortified foods were fine, iron supplements could lead to a reduction in zinc absorption.
Being deficient in zinc through poor absorption can lead to a number of issues.
Taking a zinc and iron supplement together can prevent this issue, and also sticking to a guideline amount of iron each day will also help.
3Overconsumption of iron can lead to iron poisoning (in extreme cases). Usually iron poisoning is caused by a genetic disorder or from repeated blood transfusions. However, it is also possible to get iron poisoning from overconsumption of iron through supplements and medication. Studies have found that severe overdoses of iron can lead to multi-system organ failure.
According to a 2004 study in Clinical Toxicology “From 1983 to 1991, iron caused over 30% of the deaths from accidental ingestion of drug products by children” (28).
As you can see, high doses of iron can not only lead to iron poisoning, it can lead to death – particularly in children (who are more likely to overdose) according to a 2011 study in Pediatric Emergency Care (29).
According to the NHS guidelines the recommended dosage of iron for men over 18 years of age is 8.7mg per day (30).
Women between 19 and 50 years should take 14.8mg per day (due to the increased need for iron that menstruation causes). Women over 50 should take 8.7mg per day, the same as men.
Women who are between 19 and 50 years old are the only group who should consider taking iron supplements. Particularly if they lose a lot of blood during their monthly period. Pregnant women should also ensure that they increase their iron intake as they need to produce more blood for the baby (supplementation can lead to larger birth weights (31)).
In the US the recommendation is for pregnant women to take 27mg of iron per day, roughly double the amount that a 19 to 50 year old woman is supposed to take each day (32).
In the UK the guidance is to stick to the 14.8mg per day intake. The average for pregnant women in the UK is around 10mg, so clearly more awareness of the importance of iron is needed.
Upper limits of iron per day differ depending on what age you are. According to the National Institutes of Health the upper limit for babies and children up to 13 years old is 40mg per day (33).
The upper limits for adults is 45mg per day. Any higher than that can lead to iron poisoning.
If you are suffering from iron deficiency then a doctor may prescribe you a higher dosage than that, which is obviously okay as you are deficient. But always consult with your doctor rather than experimenting yourself.
What foods are rich in iron? These foods include liver, meat, fish, tofu, eggs, nuts, beans and dried fruit.
What does iron do in the body? Iron helps create red blood cells – which help carry oxygen around the body.
How can I boost my iron levels quickly? You can eat lean red meat. You can also take iron pills, or if need be get an IV with iron straight into the blood stream.
What blocks the absorption of iron? Calcium is the only known substance to inhibit absorption of both non-heme and heme iron.
What happens when you have a lack of iron? If you do not have enough iron, your body makes fewer and smaller red blood cells . Then your body has less hemoglobin, and you cannot get enough oxygen. Iron deficiency is the most common cause of anemia.
Which type of iron is best absorbed in the body? Heme iron is the most efficiently absorbed form of iron. The absorption rate of non-heme iron supplements, such as ferrous sulfate and ferrous fumarate, is 2.9% on an empty stomach and 0.9% with food. This is much less than the absorption rate of heme iron, as found in liver, which is as high as 35%.
Can you reverse an iron deficiency? Yes, as long as you address the root issue causing you to lose so much blood an iron. After that it’s simply a matter of eat iron rich foods.
Can you die from anemia? When you’re anemic your heart must pump more blood to compensate for the lack of oxygen in the blood. This can lead to an enlarged heart or heart failure.
Iron supplementation can be very effective if you are a blood donor, if you are menstruating, or if you are pregnant. It can also be effective at treating an iron deficiency.
However, if you are getting enough iron through diet, there aren’t any real benefits to taking iron supplements. Unlike Vitamin C or Vitamin D, taking higher doses of iron won’t produce any real benefits. The only real benefit to taking iron supplements is preventing iron deficiency, so a lot of this benefit section is going to be devoted to that.
We get more than enough iron from our diet, particularly in western nations. Certain parts of Central Africa are common for iron deficiency deaths, but in Europe, Asia, and North and South America the risks of iron deficiency related deaths are very low.
There are still many people (mostly women) who are deficient though, usually from either illness or menstruation. Iron supplementation may be necessary in many cases, but an improvement in diet could also help. Eating more fortified cereals, red meat, poultry, fish, pulses, legumes etc … could make a difference.