The Quiet Threat: Understanding Latent Iron Deficiency.

Dr Rajshree Badami
February 9, 2024

Iron Marvels: A Superheroic Ode to Health and Vitality

In the vast universe of human health, iron emerges as a silent superhero, its importance echoing not just in physiology but also in the fantastical realms of fiction.

Enter the enigmatic Tony Stark, the genius behind the iconic Iron Man suits, seamlessly blending technology and the strength of iron to create a symbol of resilience. Stark becomes a living metaphor for the significance of iron, his suits serving a metaphorical ode to this indispensable super mineral in our own biological marvel.

Key role of Iron in our body

The human body contains a reservoir of approximately 3-5 grams of iron, 70% is in our blood, about 5% in the muscles, 10-20%  stored away in the liver and the remaining 5-15% as part of iron containing proteins and enzymes present within our cells.(1)

1. Oxygen Delivery: The most efficient delivery service

Iron is an integral part of two proteins that help in storing and delivering oxygen. One being hemoglobin  - a protein in our red blood cells that carries oxygen from the lungs to each and every cell of our body- like an express delivery service ensuring that each cell gets its essential oxygen dose. The other is myoglobin which stores and delivers oxygen to our hard-working muscles, keeping them in top-notch shape.

2. Powering the Energy Grid: Our very own Power House

Mitochondria - the microscopic powerhouse of our cells utilize oxygen as a fuel to run energy producing chemical reactions all day long. The iron-containing proteins in this biological dynamo keep our energy grid buzzing with efficiency.

3. The Wonders of Iron Storage: Transferrin, Ferritin, and the Hemosiderin Tag-Team

Iron is a very special mineral in the sense that our body never throws it away. Instead, it cleverly packs it into proteins called ferritin and hemosiderin, storing them away for later use. In the bloodstream, iron takes on a buddy called transferrin. When the demands go up, the stores are mobilized to make iron available for the body's needs.

What is our daily requirement of Iron and where can we get it from?

Fig 1 : Dietary sources of Iron

Fig 2: Recommended Daily Allowance of Iron in our body

Anemia and Beyond - Into the Intriguing World of Latent Iron Deficiency (LID)

When our body lacks iron, it leads to a condition called anemia. Anemia is defined by the World Health Organization (WHO), as a hemoglobin value below 13g/dl for adult men and below 12g/dl for adult nonpregnant women. Hemoglobin is responsible for carrying oxygen, so when it drops, our blood's ability to carry oxygen decreases - this is the key feature of anemia.

Globally, anemia affects nearly 1.2 billion people with iron deficiency being its primary cause.(3)

Fig 3: Identifying and Recognizing common signs of Anemia (4,5)

Prevalence of anemia among women in the age group of 15-49 years was 29.9% while 39.8% of children under 5 years were anemic globally.(6)

Fig 4: National Family Health Survey (NFHS) Stats on Anemia in India (2019-21) (7)

While global and national efforts are underway to tackle iron deficiency anemia (IDA), we must grasp that this condition is the tip of the iceberg. We need to zoom in and understand the earlier stages of iron deficiency, especially a phase called latent iron deficiency (LID). This is where the story gets interesting and understanding it can be a game-changer for our health.

The Iron Depletion Spectrum

Iron deficiency isn't a one-size-fits-all narrative – it's a spectrum, and at its far end lies Iron Deficiency Anaemia.

When the body's iron demand outpaces its supply, it starts a silent raid on its iron reserves, depleting them gradually. As the iron well runs dry, the bone marrow iron levels drop and myoglobin synthesis in the muscles take a hit. The cellular power grid, fueled by iron-dependent proteins, begins to flicker, plunging us into a low-energy state. This is where the saga begins - fatigue, loss of motivation, reduced exercise tolerance, diminished work productivity, poor concentration and low immunity. Yet, the deceiving normalcy of hemoglobin levels allows this latent stage to go unchecked. It's a silent struggle, a feeling that something is "off." These early indicators of oxygen deprivation to tissues should sound an investigative alarm into the status of the body's iron reserves.(4,5)

Fig 5: Spectrum of Iron Deficiency

The Detectable Clues: Transferrin and Ferritin

Much before anemia announces itself, the bone marrow – birthplace of red cells – witnesses a decline in iron levels, a significant clue often hidden from easy access. Here, we have transferrin and ferritin, the initial markers to dip during iron depletion and latent deficiency.
Low ferritin levels are strong indicators of iron depletion, however, their levels are elevated and unreliable in chronic diseases, transferrin saturation in that setting becomes an important guide to iron depletion. Monitoring these markers becomes crucial in deciphering the iron saga before hemoglobin takes a nosedive. (4,8).

Journeying from superhero realms, let’s have a look at some real numbers.     

Insights from the Eka Vault: Mining Health Data with Analytical Precision

There is power in numbers. But wielding it requires analytical insight. In our analytical quest at Eka, we analyzed nearly 4 lakh medical records, looking at hemoglobin and transferrin values. Here’s what we found:-

Anemia Prevalence

Figure 6(a) highlights anemia prevalence among women aged 15-49 at 52.6%, closely followed by those over 49 years at 51%. Girls under 5 had a prevalence of 41.6%, while those aged 5-15 fared slightly better at 35.3%.

Fig 6(a) : Hemoglobin distribution in females across all ages
Fig 6(b) : Hemoglobin distribution in males across all ages

Figure 6(b) displays the distribution of hemoglobin levels among men of all ages. Those above 49 years had the highest anemia prevalence at 41%, followed by 39.8% among those under 5. A slightly lower prevalence of 24.8% was seen in the 5-15 age group, while those aged 15-49 had the lowest prevalence at 17.4%.

Gender Disparities in Hemoglobin Levels

In the age group of 15-49 years, men had the lowest prevalence of anemia at 17.4% (Fig 6(b)), while women faced the highest prevalence of 52.6%( Fig 6(a)). A similar pattern persisted across all age brackets, with women consistently experiencing higher rates of anemia compared to men in the same age groups. These findings not only align with data from the National Family Health Survey (NFHS) but also surpass global averages.
Particularly worrisome is the fact that more than half of women in their reproductive years grapple with anemia. These years make women extremely vulnerable to iron depletion, not only through blood loss during the monthly cycles but also due to the increased iron demands during pregnancy, childbirth and lactation. This is the time when the health of the mother and her child are deeply intertwined, and hence, it is of critical importance to address this health issue in the mother in order to safeguard the well-being of her child.

Insights of Latent Iron Deficiency Anemia from Non-Anemic Individuals

As we delved into understanding Latent Iron Deficiency (LID), our focus shifted to a specific group: Individuals aged 15-49 years and children aged 5-15 years with normal hemoglobin levels. We examined their transferrin values, a marker of iron stores in the blood. A transferrin saturation below 16% was taken as the marker of iron depletion, although some studies suggest a cutoff of 20%.(4,5) Here are the findings:

Fig 9: Distribution of transferrin saturation % in Age 5-15 years age group
Fig 10 : Distribution of transferrin saturation % in 15-49 years age group

The curves for Transferrin Saturation % in both the age groups (Fig 9 and Fig 10) lean towards the left and peak around the lower cut off of 16% indicative of depleted iron stores, especially in women and children between 5-15 yrs.

A remarkable 31% of women were found to have low transferrin levels with normal hemoglobin in contrast to 9% in men of the same age group. 32% of children aged 5-15 years showed low transferrin levels.

These findings highlight a cohort possibly experiencing latent iron deficiency, showing early signs,but often being left undetected and untreated owing to their "normal" hemoglobin levels.

The Call for Attention: Undetected Iron Scarcity in Women and Children

Addressing Latent Iron Deficiency (LID) in the cohort of women and children becomes paramount. Undetected LID will set a woman up for Iron Deficiency Anemia during and after her pregnancy. Iron deficiency poses an added risk to the developing baby - lower birth weight, preterm deliveries, impaired cognitive development and depleted iron reserves - perpetuating the cycle of hidden iron scarcity. This is an important cohort that needs special attention as far as early detection of iron depletion is concerned. A conscious search and early management of iron deficiency in this subgroup will prevent a cascade of events that might lead to frank anemia and related morbidities in the future. (9)

Keeping Iron Depletion at Bay

Awareness about your iron status along with informed interventions can keep LID away. Here’s what you can easily do to prevent it.

  1. Be sure to include iron rich and iron fortified foods in your daily diet.
  2. Consume Vitamin C rich foods: Citrus fruits like lemons, oranges and Indian gooseberries (amla) have abundant vitamin C which helps the body to absorb iron efficiently.
  3. Monitor blood loss during menstrual cycles and seek advice if the bleeding is too heavy.
  4. Do not dismiss symptoms like fatigue, lack of interest and weakness as lifestyle or stress-related complaints, instead get a health check done to look for your iron status among other tests.

Scripting Your Wellness Voyage: The Importance of Monitoring Your Vitals

Snapshot to Story: Weaving Health Vitals into a Tapestry"

Health is more a journey than a destination. While we take snapshots of our health along the way by recording our health vitals at different points in time, everything really needs to be woven into a tapestry to get the essence of where we are heading.

Create Your Own Health Story

When you regularly check and record your health vitals, let’s say your hemoglobin or transferrin values, it's like writing down parts of your health story. Each time you do it, you add a new page, and over time, you can see patterns. Any deviation from the pattern (like a twist in the plot!) will alert you to take charge of your iron status and seek advice before it can seriously affect your health and quality of life. The Eka Care App transforms your health information into a comprehensive narrative, providing an overview of your well-being through time. It uniquely showcases all your vitals in relation to your age and gender cohort, giving a tailored understanding of your health status with personalized insights.

In the wise words of Tony Stark, "Sometimes you gotta run before you can walk." In our pursuit of well-being, embracing prevention is the bold stride forward. Regular health assessments, vigilant monitoring of key vitals, and seeking expert advice are akin to taking that bold stride, ensuring we march forward with the vigor of a superhero in our daily lives.


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2. Vasudevan DM, Sreekumari S, Vaidyanathan K. Textbook of biochemistry for medical students. Seventh edition. New Delhi: Jaypee Brothers Medical Publishers (P) LTD; 2013. 791 p.

3. Kassebaum NJ, Jasrasaria R, Naghavi M, Wulf SK, Johns N, Lozano R, et al. A systematic analysis of global anemia burden from 1990 to 2010. Blood. 2014 Jan 30;123(5):615–24.

4. Al-Naseem A, Sallam A, Choudhury S, Thachil J. Iron deficiency without anaemia: a diagnosis that matters. Clin Med. 2021 Mar;21(2):107–13.

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9. Juul SE, Derman RJ, Auerbach M. Perinatal Iron Deficiency: Implications for Mothers and Infants. Neonatology. 2019;115(3):269–74.