How Much Iron Do I Need?

Iron is a very unique nutrient.

First, unlike other nutrients, your body doesn’t have a regulated way of excreting it. The only iron you lose is via blood, sweat, and loss of skin cells. Instead, it is constantly recycled by your body. Your diet, therefore, needs to only supply enough iron to replace the amount that you are losing on average each day.

Second, unlike other nutrients whose recommended daily intake is affected only by gender and age, daily iron requirements are also affected by the composition of your diet. Specifically, vegans and vegetarians have a considerably higher requirement for iron than omnivores.

Below I have provided the current recommended daily intakes of iron for each age, gender and vegan/vegetarian status, and offer an explanation for the higher requirements in women and vegans/vegetarians.


Children

Age Not vegetarian or vegan Vegetarian or vegan
All
1-3 years 9 mg/day 16.2 mg/day
4-8 years 10 mg/day 18 mg/day
Boys
9-13 years 8 mg/day 14.4 mg/day
14-18 years 11 mg/day 19.8 mg/day
Girls
9-13 years^ 8 mg/day 14.4 mg/day
14-18 years^ 15 mg/day 27 mg/day

Adults

Age Not vegetarian or vegan Vegetarian or vegan
Men
19+ years 8 mg/day 14.4 mg/day
Women
19-50 years^ 18 mg/day 32.4 mg/day
51+ years^ 8 mg/day 14.4 mg/day

^An important note on female requirements for iron 

It is important to note that there is an assumption being made here that girls under 14 years of age do not menstruate, while it is also assumed that all girls over the age of 14 years do menstruate. If menstruation occurs earlier, or later, then iron requirements are likely to be different than those provided here, and you are best to talk to your healthcare practitioner about your specific requirements. Keeping an eye out for some of the symptoms of iron deficiency is also a good idea. 

As with the iron requirements for children, it is also assumed that women under 50 years of age are menstruating, while it is also assumed that all women over 50 years of age are not menstruating. Again, if this is not the case for you, then talking to your healthcare provider, and keeping an eye out for symptoms of iron deficiency is a great idea.

Why do vegetarians and vegans need more iron? 

As discussed in my blog post on the difference between haem and non-haem iron, iron is present in foods in two forms, haem iron and non-haem iron. In brief, haem iron is absorbed quite effectively, while non-haem iron is not absorbed as effectively. 

In a mixed Western diet, about 18% of the iron you consume is absorbed. In contrast, on a vegetarian diet, only about 10% of the iron you consume is absorbed—a result of eating mainly non-haem iron. 

So, vegetarians and vegans need to account for the poorer absorption of non-haem iron by consuming more iron per day—around 80% more. So, as you can see in the tables above, vegetarians and vegans have a 80% greater requirement for iron per day. 

While you can take some measures to reduce the factors that make non-haem iron poorly absorbed, it is still sensible to observe this increased requirement, as we will not be able to fully overcome all the absorption issues with non-haem iron.


How much iron is too much?

Population Upper Level
Children and adolescents
1-3 years 20 mg/day
4-8 years 40 mg/day
9-13 years 40 mg/day
14-18 years 45 mg/day
Adults 19+ years
Men 45 mg/day
Women 45 mg/day

How do I know if I am not consuming enough iron?

There are a few things you can do to make sure you are consuming enough iron.

  1. Look at your diet: if you aren’t consuming a sufficient quantity of foods high in iron, then you may be at risk of iron deficiency. 

  2. Take a close look at your meals: If you are consuming lots of foods and drinks that inhibit iron absorption, then you may be at risk of iron deficiency. 

  3. Look out for the common symptoms of iron deficiency.

If you have any concerns, get in contact with your general practitioner. If you do have iron deficiency, or are on the borderline of iron deficiency, make a booking with a nutritionist who specialises in managing iron deficiency.


Reference

  1. https://www.nrv.gov.au/nutrients/iron