Getting enough iron

Did you know?

Vitamin C can increase the absorption of non-haem iron - so when you eat plant foods that contain iron also eat foods high in vitamin C, like kiwifruit, citrus fruit, tomatoes and broccoli.

Iron deficiency

This is a significant problem in developed countries around the world, including New Zealand. We need iron to carry oxygen from our lungs to the rest of our body, to maintain a healthy immune system and help with energy production. Our need for iron differs over our lifetime and inadequate intakes are common.

Who is at risk of iron deficiency?

• Infants, children and teenagers, as they grow quickly.
• Teenage girls and adult women due to monthly blood loss.
• Pregnant women, as their iron requirements increase considerably with the growing foetus.
• Athletes and very active people as they often have higher losses, eg, from strenuous exercise, and altered food intake.
• Vegetarians, as they may not eat sufficient iron-containing foods.

Three three stages of adult iron deficiency

Your GP can arrange a blood test to check for the 4 indicators of deficiency: serum ferritin (storage iron), serum iron, total iron binding capacity (TIBC) and haemoglobin (red cell pool). If your iron levels are normal then you will be within the healthy range for all indicators. As iron deficiency progresses, the indicators fall outsife of the healthy ranges.

* Source: Normal levels from Diagnostic MedLab Ltd

Symptoms of iron deficiency

• fatigue
• lethargy
• impaired learning
• reduced resistance to cold
• more frequent infections.

Recommended dietary intake for each life stage

 * RDI: The average daily dietary intake level that is sufficient to meet the nutrient requirements of nearly all (97-98%) healthy individuals in a particular life stage and gender group

How to increase your iron intake from food

Iron is found in many foods including red meat, chicken and seafood. There are two forms of iron: haem and non-haem. Haem iron is found only in animal foods and non-haem is found in both plant and animal foods.

Your body will absorb haem iron more easily than non-haem, with about 25% being absorbed compared to only about 5% of non-haem iron. The absorption of iron is influenced to some degree by the body’s iron stores. If your stores are low, then you will absorb more iron than someone whose stores are in the normal range.

Choosing animal protein sources each day can help to increase your iron intake.

Haem iron sources

Non-haem sources

Source: Food Works 2007, Version 5, Service Pack 1. Xyris Software. Tbsp= tablespoon, tsp = teaspoon.

Is there anything in food that can inhibit iron absorption?

Polyphenols, oxalate, phytates and soy protein can inhibit iron absorption. Dietary fibre and calcium have also been shown to affect the absorption of iron. It is important to eat a balanced diet and to weigh up the benefit of each food that you eat.

• Polyphenols – such as tannins are found in tea, coffee and cocoa and inhibit iron absorption.
• Oxalate – is found in foods such as beetroot, rhubarb and spinach. It forms a complex with iron and is then makes it unable to be absorbed.
• Phytates – can be found in wholegrain breads, cereals, grains, seeds, nuts, vegetables and fruit. They bind to iron and make it unavailable for the body to absorb.
• Soy protein – inhibits the absorption of non-haem iron absorption regardless of its phytate content. However, fermented soy products improve the bioavailability of iron.

Enjoy a cup of tea between meals rather than with meals, so you don't inhibit iron absorption.

If your iron levels are below the normal range, what can you do?

• Eat foods high in iron.
• Eat foods that enhance iron absorption with your main meals.
• Limit foods that inhibit iron absorption.
• Discuss iron supplementation with your dietitian or doctor: 

1.  It is important to check if there are any other causes of low iron stores before you start taking a supplement for example: blood loss, coeliac disease.
2. Oral iron supplements that can be prescribed include ferrous sulphate and ferrous glutamate (both have an option of containing vitamin C).
3. Iron is also a component of most pregnancy multi-vitamins.
4. Iron supplements can be brought over the counter from pharmacies and at the supermarket, the iron content can vary considerably between brands.
5. Iron supplements can have side effects such as constipation or diarrhoea that you need to consider.
6. In some circumstances, your doctor may recommend a course of iron injections, discuss this in detail with them.

Article supplied by Auckland Dietetics Service

Photo credit: Zsuzsanna Kilian