Study: Low Iron Linked to Brain Fog in Perimenopause

A new study from the University of Oklahoma offers hope for women experiencing brain fog and memory issues in perimenopause. Researchers have found that having healthy iron levels in the blood can help women perform better on thinking and memory tasks during this transition.

What Did the Study Find?

The research, published in the journal Nutrients, looked at women going through the menopause transition. The team measured iron levels in the blood, checked iron in the brain with MRIs, and tested memory and attention. They discovered:

• Women with lower-than-ideal blood iron (even if not technically “deficient”) did worse on memory and attention tests.
• Women with healthy blood iron performed better on these tasks.
• Importantly, having enough iron in the blood did not mean there was too much iron in the brain. This is good news, since too much brain iron has been linked to diseases like Alzheimer’s.

Why Does Low Iron Matter During Perimenopause?

Before menopause, women lose iron every month through their periods. As periods stop, iron loss slows down. But if your iron stores are already low, you may not “catch up” quickly, which can affect how your brain works.

Michael Wenger, Ph.D., a professor of psychology at the OU College of Arts and Sciences and a lead author of the study, says that even small drops in iron can slow down reaction times and make thinking tasks harder.

“When a woman makes the menopausal transition, she’s no longer losing blood on a monthly basis, which means she’s no longer losing iron,” says Dr. Wenger. “We wanted to see if the cost of being low on iron disappears during the menopausal transition. Very few studies have been done in this area.”

The research team checked iron levels in the blood, used MRIs to look at iron in the brain, and tested thinking and memory skills. While none of the women were officially iron deficient, many had lower iron levels than recommended for their age. Those with lower blood iron didn’t do as well on memory, attention, and cognitive tests.

“Our previous research has shown that being iron-deficient extracts some serious costs in terms of cognitive performance,” Wenger said. “If I were to give a woman with iron deficiency a simple task in which she presses a button every time an asterisk appears on a screen, the deficiency would cost her about 150 milliseconds. That doesn’t sound like a lot, but we make simple decisions like that when we choose every word we say in a sentence. Those 150 milliseconds add up."

Being deficient in iron is not the same thing as being anemic. Low iron is a risk factor for anemia, Wenger said, but people can become anemic for other reasons. However, women visiting their OB-GYN typically are not tested for iron deficiency, which may be a missed opportunity.

“Low iron could easily be one of the reasons that a woman is experiencing brain fog during the menopausal transition,” he said. “It also may be why some women talk about their eyesight changing during menopause. Iron is a critical element in the synthesis of the neurotransmitter dopamine, and the eye is dependent upon dopamine for basic signaling at the first point of contact with light.”

Although taking iron supplements is usually not the best course of action since they cause major gastrointestinal side effects, a low dose could be effective, as would diet changes to consume more foods high in iron, Wenger said.

“Making these minor changes could make a woman’s transition from pre- to post-menopause easier to bear,” he said.

Does More Iron Mean More Risk?

The study found that higher blood iron did not lead to more iron in the brain. This means women can aim for healthy iron levels in their blood without worrying about increasing their risk of brain diseases.

What Should Women Do?

• Low iron is different from anemia, but both can cause fatigue and brain fog.
• Many women are not routinely tested for low iron at the doctor’s office, so it’s worth asking about if you have symptoms.
• Instead of high-dose iron supplements (which can upset your stomach), try eating more iron-rich foods like lean meats, beans, spinach, and iron-fortified cereals. Pairing these with vitamin C-rich foods can help your body absorb iron better.

If you’re experiencing brain fog or memory problems during perimenopause, low iron could be part of the reason. Keeping your iron at a healthy level may help you think more clearly and feel better as you move through this stage of life. Talk to your medical provider for more information.

This content is for educational purposes only and is not medical advice.