Fixing Iron Deficiency: What to Test, What to Take, and Why

With expert insights from Dr Libby Weaver’s book, Fix Iron First

Iron deficiency is one of the most common nutritional issues in Aotearoa, especially among women. If you’re feeling unusually tired, low in energy, or having trouble focusing, low iron levels could be a contributing factor.

But not all iron supplements are created equal. Before reaching for one, it’s essential to know what your body actually needs.

In her book Fix Iron First, nutritional biochemist Dr Libby Weaver explains what really works when it comes to restoring iron levels safely and effectively. In this article, we share her expert advice, along with how to test your levels and what to look for in a high-quality supplement.

1. Know Your Levels First

Symptoms of iron deficiency, such as fatigue, brain fog, pale skin, or dizziness, can be vague and overlap with those of other conditions. That’s why testing first is crucial.

The Smith Biomed Ferritin (Iron Deficiency) Test is an at-home finger-prick blood test that measures ferritin, your body’s iron storage protein. Low ferritin is a clear early indicator of iron deficiency, even before anaemia develops.

Testing first helps you:

Confirm if low iron is actually the issue
Avoid unnecessary supplementation
Take the proper steps with your GP or health provider

If your test results show low ferritin levels, consult a doctor or a qualified health professional for personalised advice.

2. Support Iron Absorption Naturally

Iron doesn’t work alone. Your body needs the proper nutritional support to absorb and use it effectively.

Dr Libby highlights the importance of cofactors, nutrients that work with iron to support healthy levels:

Vitamin C: boosts absorption
Copper: helps transport iron in the blood
Vitamin A & Beta-carotene: support storage and mobilisation

You can support your body’s iron uptake by:

Pairing iron-rich foods with vitamin C (e.g. lentils + citrus, beef + capsicum).
Avoid consuming coffee, tea, dairy products, or fibre supplements for at least two hours before or after eating iron-rich foods or taking an iron supplement, as these can interfere with iron absorption.
Supporting gut health, as poor digestion can block absorption.

3. Choose the Right Form of Iron Supplement

Not all iron supplements are equal. Many are made from synthetic iron salts, which Dr Libby refers to as “harsh” due to their tendency to:

Irritate the gut
Cause constipation
Raise hepcidin levels and impair absorption

She recommends choosing gentler, bioavailable forms of iron, such as:

Ferrous bisglycinate: better absorbed and well tolerated
Supplements with Ferritin-iron from food-based sources, such as organic peas

These options are more effective and less likely to cause side effects.

“Supplementation is crucial. However, the effectiveness depends significantly on the quality and form of the iron as well as the additional ingredients in the supplements you take.”

— Dr Libby Weaver

4. Know When to Seek Extra Help

Even with the right supplement, some individuals still struggle to replenish their iron levels. Common underlying causes include:

Heavy menstrual bleeding
Gut health issues (like coeliac disease)
Low dietary intake
Chronic inflammation or autoimmune conditions

If your ferritin remains low despite supplementation or you feel worse after starting iron, consult your healthcare provider. Further testing may be necessary to identify the underlying cause.

Start With a Test, Not a Guess

Restoring iron levels isn’t just about taking a supplement; it’s about understanding your body and supporting it properly.

At Smith Biomed, we believe a test-first approach leads to better outcomes. Our Ferritin (Iron Deficiency) Test offers a fast, reliable way to check your iron status from the comfort of home.

👉 Check your iron levels today
If your results are low, consult a healthcare professional for guidance on the best next steps.

1. Know Your Levels First

2. Support Iron Absorption Naturally

3. Choose the Right Form of Iron Supplement

4. Know When to Seek Extra Help

Start With a Test, Not a Guess

Further Reading: Understand Your Iron Health