Iron deficiency in women — food sources of iron and why it is so important

Iron deficiency is one of the most common nutritional deficiencies in the world, particularly in women, this is due to menstruation and the loss of iron through menstrual blood. Iron deficiency is when there are insufficient iron stores to meet the body’s needs. The ‘normal’ range of ferritin (stored iron in the body) will say anywhere between 30-200ug/L for a female. Anything below 30 indicates iron deficiency.

We are often only made aware of deficiency if we are below the ‘normal’ range, however, even within the ‘normal’ range, results can be far from optimal, particularly if you are experiencing any of the symptoms I have listed below. Always seek the advice of a health professional when interpreting blood results. 

A few things to consider and rule out when investigating the cause of low iron.

• Coeliac disease

• Internal bleeding

• Inability to absorb iron

• Endometriosis

• Gut diseases such as IBD

• Inadequate intake from the diet

• H.Pylori

• Pregnancy can also cause low iron as the demands are high

Some of the most common signs and symptoms associated with iron deficiency. 

• Fatigue

• Headaches

• weakness

• Pale skin

• Pale conjunctiva

• Shortness of breath

• Hair loss

• Irregular heartbeat

• Cold hands and feet

Why is iron so important and where can we get it in the diet?

Iron is required for many bodily functions, the most well-known being its role in oxygen transport around the body. Iron also contributes to normal cognitive function, helps maintain immunity and assists in the conversion of food to energy.

Dietary iron occurs in two forms: non-heme which comes from plant-based foods such as legumes, fruit, vegetables and pulses, and heme which comes from animal-based foods such as meat, poultry and fish.

Heme iron is much more bioavailable than non-heme iron, meaning it is more easily absorbed and utilised by the body. Certain foods that majorly inhibit the absorption of iron in the body, these include polyphenols, phytic acids, tannins found in black tea and especially caffeine.

It is important to avoid these when consuming iron-rich foods to ensure your body can absorb the iron sufficiently. For example, it is recommended to have tea and coffee at least 2 hours away from consumption of an iron-rich meal or iron supplement.

Studies have shown that consumption of caffeine with an iron-rich meal can reduce absorption by up to 39%. On the plus side, certain foods can increase the absorption of iron, the most common being vitamin C and some amino acids. Citrus fruits such as lemons and oranges are great to consume with iron-rich meals or supplements to assist in the absorption process.

How much iron should we be consuming each day?

The RDI for women aged between 19 – 50 years old is 18mg/day. To give you some perspective 100g of raw spinach roughly contains roughly 1.2mg of non-heme iron and there is roughly 11mg of heme iron in 100g of chicken liver (Nutrition Australia, 2020).

For a female to be getting the required amount of iron each day she needs to be including a variety of iron-rich foods in the diet, consumed with vitamin C for optimal absorption and avoiding inhibitors around these iron-rich meals. 

Plant-based sources of iron:

• spinach, kale and silverbeet

• lentils (be sure to soak them to remove some of the phytates which inhibit absorption)

• beans

• tofu

• tempeh

• soybeans

• seeds: pumpkin, sesame, hemp and flaxseeds

• nuts and nut butter almond, cashew, pine nuts and macadamia

• oats, spelt, amaranth

• quinoa

Animal sources of iron:

• chicken liver

• oysters

• salmon

• chicken

• beef

• turkey

• sardines

• kangaroo

• duck