Things that blocks absorption are compounds such as phytates, "whole grains, beans, nuts", polyphenols/tannins "tea, coffee, cocoa, red wine and some veggies and fruits, as well as calcium, including dairy supplements that bind to iron.
Even certain proteins like soy, egg whites etc and medications like proton pump inhibitors, which reduce stomach acid can block iron absorption.
These substances interfere with iron uptake, especially non-hem plant based iron that makes it less available for your body to use.
Foods that block iron absorption are yogurt, cheese, milk, soy, tofu, chocolate, ice cream, popcorn, sardines, canned salmon and even pomegranate.
Low iron can also affect sleep and cause insomnia as well as daytime fatigue, restless leg syndrome and poor sleep quality because iron is vital for transport of oxygen and also for neurotransmitter function in the brain, which leads to sleep disturbances like difficulty in falling asleep and difficulty in staying asleep as well as restless limbs.
However the connection between low iron and sleep can be complex and some research suggests poor sleep can get worse with anemia.
Causes of iron depletion in the body are blood loss, like heavy periods or internal bleeding from ulcers and cancer, not enough dietary intake, poor absorption of iron, celiac disease, surgery and increased demand for iron, like through rapid growth, pregnancy, intense exercise and even certain medications, like NSAIDs and foods/drinks, tea coffee, tannins can all hinder absorption of iron in the body and lead to iron depletion.
The number one cause of low iron is bleeding in the stomach and intestines.
Bleeding in the stomach and intestines can be caused by bowel cancer, stomach cancer or stomach ulcers, or even by taking non steroidal anti inflammatory medications also known as NSAIDs.
But in men and post menopausal women, the most common cause of low iron in the body is bleeding in the stomach and intestines.
However other things can also cause low iron.
Bypassing or removing intestinal tissues, which help take in iron and other nutrients also raises a person's risk of iron deficiency anemia.
And people that have certain conditions, which affect digestion, like celiac disease, bowel disease, like ulcerative colitis and Crohn's disease, peptic ulcers and kidney disease are also at risk of low iron in the body.
Low iron in the body, which is also known as iron deficiency is when the body's iron stores are too low.
Other common causes of low iron or iron deficiency include not getting enough iron in your diet, chronic blood loss, pregnancy and even vigorous exercise.
And even some foods and drinks affect how much iron your body absorbs.
Anemia, especially iron deficiency anemia, can and does very commonly cause headaches, as the lack of red blood cells or hemoglobin means less oxygen reaches the brain, which leads to concentration issues, fatigue and headaches or migraines.
A study showed that nearly 80 percent of people with iron deficiency experienced headaches.
The headaches with iron deficiency anemia can range from mild to severe, and sometimes feel like migraines, often linked to low iron affecting brain chemicals like serotonin, and are also treatable with iron supplements and proper diet.