Understanding Iron and Women’s Nutrition
Iron deserves special attention in women’s nutrition. Because of menstrual blood loss and the demands of pregnancy, women of reproductive age need considerably more iron than men, and they are the group most likely to run short. Knowing your needs and the signs of deficiency helps you stay ahead of it.
Key points
- Women aged 19 to 50 need 18 mg of iron a day; in pregnancy the requirement rises to 27 mg.
- Heavy periods and pregnancy are the main reasons women develop iron-deficiency anemia.
- Tiredness has many causes, so ask for a blood test before taking iron supplements.
Why women need more iron
The body uses iron to make hemoglobin, the protein in red blood cells that carries oxygen. Iron is lost whenever blood is lost. Regular menstrual bleeding means that women of reproductive age lose iron every month, and those with heavy periods lose more. During pregnancy, the body needs extra iron for the increased blood volume and for the developing baby.
How much is needed
Recommended daily amounts from the NIH Office of Dietary Supplements:
- Teen girls 14 to 18: 15 mg
- Women 19 to 50: 18 mg
- Pregnancy: 27 mg
- Breastfeeding: 9 mg
- Women 51 and over: 8 mg
For comparison, adult men need 8 mg. After menopause, a woman’s requirement falls to the same level.
Iron-deficiency anemia
When iron stores are too low, the body cannot make enough healthy red blood cells. The Office on Women’s Health notes that iron-deficiency anemia affects more women than men, and that the risk is highest for women who are pregnant or who have heavy menstrual periods.
Symptoms
Symptoms often develop slowly and may include:
- tiredness and weakness;
- pale skin;
- shortness of breath;
- dizziness or headaches;
- cold hands and feet;
- brittle nails;
- a fast or irregular heartbeat.
Who is at higher risk
- Women with heavy or long periods
- Pregnant women
- Women who have recently given birth
- Vegetarians and vegans
- Frequent blood donors
- Women with digestive conditions that affect absorption
Food sources of iron
Heme iron (well absorbed)
- Lean red meat
- Poultry
- Fish and shellfish
Non-heme iron
- Iron-fortified breakfast cereals and breads
- Beans, lentils and chickpeas
- Tofu
- Spinach and other dark leafy greens
- Nuts, seeds and dried fruit
Vegetarians need almost twice as much iron, because the body absorbs non-heme iron less efficiently.
Getting more from your food
- Pair plant sources of iron with vitamin C: beans with tomatoes, cereal with berries, spinach with a squeeze of lemon.
- Include meat, fish or poultry in the same meal if you eat them; they improve absorption of non-heme iron.
- Take calcium supplements at a different time from iron-rich meals or iron supplements.
Heavy periods and iron
If you regularly soak through a pad or tampon every one to two hours, pass large clots or have periods lasting longer than seven days, see a doctor. Heavy periods are treatable, and treating the cause is as important as replacing the iron.
Supplements
Iron supplements treat confirmed deficiency, and some women’s multivitamins contain iron to help meet daily needs. Our Women’s Multivitamin with Iron is a once-daily option; it is not a prenatal supplement.
Points to remember:
- Test first. A blood test shows whether you are deficient and how much you need.
- Side effects can include constipation, nausea and dark stools.
- Upper limit: 45 mg a day for adults unless a doctor prescribes more.
- Interactions: iron can reduce the absorption of some medicines, including levothyroxine.
- Child safety: iron supplements can be fatal to young children in overdose. Keep them locked away.
Pregnancy
Iron needs rise sharply in pregnancy, and prenatal supplements usually contain iron. Your maternity care provider will check your blood count and advise on the right dose.
After menopause
Once periods stop, iron needs drop to 8 mg a day. Most postmenopausal women should not take iron supplements unless a doctor recommends them, because the body has no natural way to get rid of excess iron.
Other nutrients that work with iron
- Vitamin C improves absorption.
- Folate and vitamin B12 are also needed to make red blood cells; a shortage of either causes a different kind of anemia.
When to see a doctor
Make an appointment if you have persistent tiredness, breathlessness, heavy periods or any of the symptoms above. Anemia has several possible causes, and the right treatment depends on the cause.
The bottom line
Women of reproductive age need plenty of iron, and food is the first place to find it. If you suspect you are low, ask for a blood test before supplementing. See nutritional support in our women’s health department.
Sources
- NIH Office of Dietary Supplements. Iron.
- Office on Women's Health. Iron-deficiency anemia.
- NHS. Heavy periods.
- Office on Women's Health. Healthy eating and women.
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