Why do women need more iron than men?
Written by Dr Tosin Sotubo @mindbodydoctor
Iron is essential to the life of men, women, adults, and children. It plays an important role in energy metabolism, cognitive function, immune function and primarily the formation of red blood cells and oxygen transport around the body. The amount of iron an individual needs each day depends on their age, sex, and other factors such as underlying health conditions. Iron is particularly important to women especially those of childbearing age as their iron requirement needs are almost double that of men.
Iron deficiency (the lack of iron) is the most common nutritional deficiency in the world. If left unaddressed, it can lead to anaemia. The population that suffers the most is women. In 2011 roughly 29% of non-pregnant women, and 38% of pregnant women worldwide aged 15–49 years were anaemic.
Why Do We Need Iron?
Iron is an essential mineral that the body needs for every day function. One of the most vital functions of iron is heme synthesis. The body uses iron to make haemoglobin a protein found in the red blood cells. This haemoglobin carries oxygen from the lungs to the rest of the body. A lack of iron means the body can’t make enough red blood cells to carry the oxygen and this can lead to iron deficiency anaemia, resulting in feelings of tiredness, weakness, shortness of breath and difficulty concentrating. Other signs include palpitations, hair loss and brittle nails.
One of the functions of iron is in energy production. Cells require iron to convert energy from food into an energy source the body can utilise.
Iron also plays an important role in maintaining a healthy immune system. A low iron store can result in a poor supply of oxygen to damaged cells, tissues and organs, decreasing the body’s ability to fight off infections.
There is also research to show adequate iron levels play an important role in cognitive ability including contraction, problem solving and memory.
Our bodies do not create iron and therefore we need to make sure we include sufficient iron as part of our diets. The best source of iron is red meat and lesser amounts are found in chicken and fish, however iron can also be found in certain plant foods which we will explore later in this article.
Why do Iron Needs Differ Between Women and Men?
Men and women have different requirements. The main reason for this is mostly due to monthly menstruation. After menopause when women no longer experience monthly blood loss, the requirements equal out between genders. Other life stages women may experience such as pregnancy also impact a woman's iron requirements.
It’s recommended that adult men (aged 18 and over) need approximately 8.7mg of iron a day, whereas women (aged 19 to 50 years) need about 14.8mg a day and women over 50 years of age need 8.7mg of iron a day.
Menstruation is the most common cause of iron loss worldwide. When blood is lost every month during menstruation, the iron within those red blood cells is also lost. A person is considered to have heavy menstrual bleeding when their menstrual period is typically over 80 ml. Therefore, iron intake is particularly important in women and in those who experience heavy periods.
In turn, excessive blood loss and the reduction in iron via menstruation could impact blood flow and lead to missed or late periods and it can turn into a vicious cycle.
Iron in Pregnancy
Iron becomes very important in pregnancy for the mother and just as importantly to support the growing foetus and placenta. When pregnant the blood volume in the body increases by almost 50% and therefore dietary iron requirements can increase especially in the second and third trimester. Low iron can be common in pregnancy especially in those who experience sickness or are carrying more than one child and often iron supplements may be prescribed.4
Iron and breastfeeding
Iron is also important during breastfeeding because a woman still needs to meet her iron requirements as usual and to provide enough for the production of breast milk. Whilst breast milk naturally contains iron the good thing is that babies are born with iron stores and this is usually sufficient to last them until 6 months of age when they start to venture into solids.
Why women who are vegetarians or vegans need to take note.
It’s well known that animal foods such as red meat are one of the best sources of iron, however there are plenty of options for vegetarians and vegans. Animal foods contain heme iron which is easily absorbed however non-heme iron found in plants is not as easily absorbed. Therefore, vegetarians and vegans need almost twice as much iron. Eating foods rich in Vitamin C alongside iron-rich foods can also help improve iron absorption.
Plant based iron rich foods include:
- Pulses including beans, lentils and peas
- Dark green vegetables, kale spinach
- Fortified cereals
- Dried fruit such as raisins, apricot and figs
- Wholegrains including brown rice and brown bread
Overall, iron is an essential nutrient to life for men and women, but we know that women especially during their reproductive years have higher requirements and need to pay closer attention to their daily iron intake.
 Cherayil BJ. The role of iron in the immune response to bacterial infection. Immunol Res. 2011;50(1):1–9.
 Jáuregui-lobera I. Iron deficiency and cognitive functions. Neuropsychiatr Dis Treat. 2014;10:2087-95.