Can Low Iron Affect Your Mood and Brain? Iron Deficiency, Brain Fog, Anxiety and Depression

“I can't concentrate.”

“My memory isn't what it used to be.”

“My brain feels slow.”

“I am more anxious than usual.”

“I feel mentally exhausted.”

These symptoms deserve to be investigated, particularly when they occur alongside fatigue, heavy menstrual bleeding, sleep disruption or other symptoms associated with iron deficiency.

Iron is often discussed as though its only job is preventing anemia.

It is much more complicated than that.

Iron is also important for normal brain function, neurotransmitter activity and cognition.

Can low iron cause brain fog?

Iron deficiency has been associated with changes in complex cognitive tasks including sustained attention, working memory, planning, inhibitory control and emotional regulation.

Even in people who are iron deficient without anemia, research has observed slower cognitive functioning, reduced activity levels and lower cognitive endurance.

In everyday life, that may look like struggling to concentrate for long periods, feeling mentally fatigued more quickly or having greater difficulty with tasks requiring sustained attention.

And for women experiencing perimenopause, this can become even more complicated.

Perimenopause itself can be accompanied by cognitive complaints, including changes in concentration and memory.

This means we need to be careful about automatically deciding that brain fog in a woman in her 40s is “just hormones.”

Iron status may be another piece of the puzzle.

Why does iron affect the brain?

Iron is involved in several neurological processes.

It has roles in neuronal metabolism and myelination and is involved in brain systems that use neurotransmitters including dopamine, serotonin and noradrenaline.

Iron deficiency can therefore potentially affect systems involved in attention, motivation, mood, memory and executive functioning.

Key brain regions involved in learning, memory and executive function may also be affected by inadequate iron status.

This is one of the reasons why Dr. Nicole Roberts, Ontario Naturopathic Doctor, considers nutrient status as part of a broader clinical assessment when women present with cognitive complaints.

Can iron deficiency cause depression?

Research has identified associations between iron deficiency, anemia and depressive symptoms.

Iron deficient or anemic women have been reported to be approximately 1.66 times more likely to experience depressive symptoms compared with women who are iron replete or not anemic.

Iron status can also be important during pregnancy and postpartum.

Pregnancy and lactation substantially increase iron demands, potentially depleting maternal stores. Maternal iron deficiency anemia has been associated with changes in postpartum reasoning and emotional responses as well as an increased risk of postpartum depression.

This does NOT mean that iron deficiency is the sole cause of depression.

Mental health is complex.

But it does mean iron status can be a relevant physiological factor worth considering within an appropriate assessment.

Can low ferritin cause anxiety?

Anxiety has been reported as a behavioural effect associated with iron deficiency, although research is less consistent than it is for some other iron related outcomes.

Some research has not found a direct relationship between ferritin and anxiety unless sleep disruption was also present.

That is important because sleep, mood, cognition and iron status may interact rather than existing as completely separate issues.

The goal should not be to reduce anxiety to a ferritin result.

The goal is to recognize that physiological factors can contribute to how a person feels and function.

Why is this particularly important during perimenopause?

Women experiencing perimenopause may already be dealing with changes in mood, cognition, menstrual bleeding and sleep.

If heavy menstrual bleeding is simultaneously lowering iron stores, symptoms can begin to stack on top of each other.

You may have hormonal changes affecting sleep.

Poor sleep affecting mood.

Heavy bleeding contributing to iron loss.

Iron deficiency contributing to fatigue and cognitive function.

This is why Dr. Nicole Roberts approaches women's health through an integrated lens rather than treating each symptom as though it exists independently.

When should iron status be investigated?

Women experiencing symptoms associated with iron deficiency may benefit from appropriate clinical assessment, particularly when there is a history of heavy menstrual bleeding, pregnancy, lactation or other potential sources of iron depletion.

A complete assessment may include CBC, ferritin, iron and transferrin saturation rather than relying exclusively on a single marker.

Most importantly, results should be interpreted alongside the patient in front of us.

Your symptoms matter.

Your menstrual history matters.

Your sleep matters.

Your mental health matters.

Your quality of life matters.

Women's health support in Ontario

Dr. Nicole Roberts is an Ontario Naturopathic Doctor who works with women experiencing concerns involving menstrual health, perimenopause, mental health, cognitive health and iron deficiency.

If you are struggling with fatigue, poor concentration, brain fog, mood changes or heavy periods, the goal is not to assume there is one simple explanation.

It is to investigate the contributing factors and create a treatment plan based on the full picture.