Blood Loss: The Monthly Drain

Menstruation is the #1 driver of iron loss in women of reproductive age

Each period means shedding blood and with it, iron. The heavier and more frequent the bleeding, the greater the loss.

Women with heavy periods (menorrhagia) can lose up to 5–10 times more iron per cycle than the average woman. This includes:

If your period is heavy and your ferritin hasn’t been tested recently, it’s time.

Low Dietary Iron Intake

Not all iron is created equal.

Heme iron (from meat and fish) is easily absorbed. Non-heme iron (from plants) is less bioavailable and more sensitive to inhibitors like calcium and phytates.

That’s why vegans and vegetarians are at a higher risk, especially if they’re not supplementing wisely or combining iron with absorption enhancers like vitamin C.

Increased Demand During Life Stages

There are times in a woman’s life when the body’s demand for iron skyrockets:

Even high achievers and go-getters -those who “push through” exhaustion - can burn through their iron stores without realizing it.

By the time symptoms like fatigue, poor performance, or brain fog appear, deficiency is already underway.

Malabsorption and Gut Health Issues

You can be eating enough and still become deficient if your body can’t absorb the iron. Common culprits include:

Iron is absorbed mostly in the upper small intestine. If that area is inflamed, compromised, or bypassed, your absorption drops significantly.

Chronic Inflammation or Infection

This one’s sneaky. Even if you’re eating well and don’t have obvious losses, inflammation can still hijack your iron.

Here’s how:

The liver produces a hormone called hepcidin, which blocks iron absorption and locks up stored iron during times of stress or infection.

This is the mechanism behind functional iron deficiency, when the tank looks full, but the fuel isn’t usable.

It’s common in autoimmune conditions, long COVID, endometriosis, obesity, and chronic low-grade infections.

Certain Medications

Some drugs can reduce absorption or increase losses. These include:

If you’re on these long-term, you may need more frequent ferritin monitoring and possibly proactive supplementation.

Lack of Testing or Misinterpretation of Lab Results

Even when symptoms are present, iron deficiency is often missed or misinterpreted due to outdated lab thresholds.

In most provinces, ferritin isn’t flagged until it’s below 15, and even Ontario’s new threshold of 30 is considered conservative.

But studies suggest women can have significant symptoms at ferritin levels below 50 or even 75.

If your levels are in that range, you may be told they’re “normal”, but your body may be telling a very different story.