Iron deficiency is the most common nutritional deficiency globally, and women are significantly more affected than men.
Iron deficiency is rarely discussed with the seriousness it deserves. The symptoms – fatigue, difficulty concentrating, feeling slightly off – are easy to attribute to stress, a demanding job or too little sleep. For many Swedish women, that is exactly what happens. The underlying cause goes unidentified for years.
What puts women at risk
Women lose iron through menstruation every month. For those with heavy periods – which are more common than often acknowledged – this loss can be significant enough to deplete iron stores over time, even with an otherwise adequate diet.
Dietary patterns add another layer of complexity. The shift towards plant-based eating reduces intake of haem iron – the form found in meat and fish that the body absorbs most efficiently. Plant-based iron sources exist but are absorbed less readily.
As women move through perimenopause and beyond, hormonal changes further affect how the body regulates iron. The picture becomes increasingly individual and a general assumption of adequacy is not enough.
The problem with going undetected
Iron deficiency exists on a spectrum. Full anaemia – where red blood cell production is compromised – is the end point, not the starting point. Long before anaemia develops, depleted iron stores can cause significant symptoms and affect biological function.
Standard blood tests in Swedish primary care often measure haemoglobin alone, which can appear normal even when iron stores are genuinely low. A more complete picture requires measuring ferritin – the protein that stores iron in the body. Many women with low iron stores are told their results are fine because haemoglobin has been the only marker.
This is a gap that a comprehensive blood panel closes. At EndoHealth, iron status is assessed as part of a broad analysis of over 90 health markers, giving a complete and individualised picture of where a woman's levels actually stand.
What low iron actually does to the body
Low iron does not just cause tiredness. It affects cognitive function, immune response, cardiovascular performance and mood. Research has linked iron deficiency to reduced VO2 max – a key marker of cardiovascular fitness and one of the strongest predictors of long-term health. It affects the brain's ability to regulate dopamine and serotonin. It compromises the body's ability to maintain muscle mass and recover from physical activity.
For women who are otherwise active, eating well and doing what they are supposed to do for their health, unexplained fatigue and reduced capacity are often the first signs that something is off. Iron is frequently the missing piece.
What can be done
Iron deficiency is highly treatable. Dietary adjustments, targeted supplementation and in some cases intravenous iron therapy can restore levels effectively. But the right intervention depends on understanding the underlying cause – whether it is dietary, related to absorption, hormonal or something else.
That is why assessment matters more than assumptions. Supplementing iron without understanding the full picture is not always straightforward. Too much iron carries its own risks. The goal is to understand what the body needs and why – and to act on that with precision.
Iron, hormones and the bigger picture
Iron deficiency does not exist in isolation. In women, it intersects with hormonal health, thyroid function and inflammation in ways that are easy to miss when each marker is looked at separately. A woman experiencing fatigue, brain fog and reduced physical capacity may be dealing with low iron, suboptimal thyroid function and declining oestrogen simultaneously – conditions that compound each other.
This is the kind of complexity that preventive medicine is designed to navigate. Not treating symptoms in isolation, but understanding the full biological picture and acting on it early – before the consequences become harder to reverse.
Sources
Camaschella C. Iron deficiency. Blood, 2019.
Pasricha SR, et al. Iron deficiency. The Lancet, 2021.
Beard JL. Iron biology in immune function, muscle metabolism and neuronal functioning. Journal of Nutrition, 2001.
Haas JD, Brownlie T. Iron deficiency and reduced work capacity: a critical review of the research to determine a causal relationship. Journal of Nutrition, 2001.
Ganz T. Systemic iron homeostasis. Physiological Reviews, 2013.
