Iron

Iron is an essential mineral best known for allowing blood to carry oxygen between tissues.
Except in the case of deficiency, iron supplementation has no proven benefit; on the contrary, it can lead to iron poisoning.

Iron is stored in the body as ferritin (liver, spleen, duodenum, skeletal muscle, bone marrow) and is delivered throughout the body as Transferrin (a protein in blood that binds to iron).

Sources of heme iron: oysters, beef or chicken Liver, organ meats,
Sources of non-heme iron:Fortified breakfast cereals, beans, whole grains, dark chocolate (at least 45%), lentils, spinach potato with skin, nuts, seeds, enriched rice or bread.

Foods such as legumes that are rich in phytic acid and tannins tend to have reduced iron bioavailability.

For men, iron recommendations are based on age.
For women, they are based on the estimated ages of first and last menstruation and the states of pregnancy lactation.

In children between 1 and 3, the ear 3 mg and the RDA is 7 mg.
In children between 4 and 8, the ear 4.1 mg and the RDA is 10 mg.

For children and adolescents between 9 and 18, the ear and RDA differ between the sexes due to menstruation.

For males under 14,the RDA is 8 mg, but it increases to 11 mg for ages 14 to 18.
For females under 14, the RDA is also 8 mg, but it increases to 15 mg between 14 and 18.

In men older than 18,the RDA is 8 mg.
In women between 19 and 50, the RDA is 18 mg.

For women older than 50,the RDA is 8 mg, the same as for men.
For pregnant women, the RDA increases to 27 mg.
For lactating women, the RDA decreases to 9—10 mg.

Frequently used forms of iron in supplements such as ferrous sulfate, ferrous gluconate, ferric citrate and ferric sulfate
Ferrous gluconate is usually sold in liquid form, and some clinical studies have shown that it is better absorbed than ferrous sulfate tablets.
Ferrous gluconate is more expensive than ferrous sulfate.
Ferrous gluconate contains less elemental iron than ferrous sulfate, so a greater dosage may be needed to correct a deficiency.

Anemia is often caused by iron deficiency; when there is insufficient iron to create hemoglobin, the body has carried adequate oxygen, which can cause tiredness and cognitive impairment.
Infections, heart failure, Restless leg syndrome and depression can all occur as a result of iron deficiency.

Causes of Deficiency
• Blood donation
• Surgery resulting in blood loss
• Celiac disease and gluten-free diets
• Gastric bypass surgery
• Intestinal inflammation
• Menstruation
• Pregnancy

Absorption differs for heme and non heme iron, both are primarily absorbed in the duodenum and to an extent in the upper jejunum.

Heme iron is better absorbed by the body than non-heme iron, whereas certain factors inhibit the absorption of non-heme iron.

Animal protein increases non heme iron absorption.
Bacterial (probiotics) strains seem to be able to increase iron absorption (requires more research).
Vitamin C (ascorbic acid) increases the rate at which non heme iron is absorbed from the intestines into the bloodstream.
In a meta-analysis of 21 clinical trials and 2 cohort studies, vitamin A supplementation to resolve deficiency reduced the risk for anemia increased hemoglobin and ferritin.

Calcium is a strong inhibitor of iron absorption, and avoiding the simultaneous use of calcium and iron supplements will prevent the reduced absorption of iron.
Tea, whether green or black or green coffee extract, might inhibit iron absorption, might possibly due to the presence of catechins, theaflavins chlorogenic acid.
Dietary fiber may have an acute inhibitory effect on iron absorption
Rosemary  (a source of rosmarinic acid) has also been shown to reduce non heme iron absorption.
Ingesting iron at the same time as spices rich in phytic acid or phenolic may reduce its absorption.
Phytates, oxalate and tannins can inhibit absorption of non-heme iron.
Quercetin has also been recognized as a strong chelator of iron.
Although zinc appears to be capable of' reducing iron absorption, the impact is inconsistent and the magnitude of this effect is unknown.

Negative effects of low oxygen delivery due to the curing anemia can be expected to improve athletic performance.

In a randomized single-blind placebo controlled experiment, type 2 diabetes patients with anemia saw larger decreases in Hba1c while taking iron supplements than when taking a placebo, which also correlated with a greater drop in fasting blood sugar. (more research is needed).

Depression is a symptom of iron deficiency anemia, increasing iron levels can likely improve the condition.

High doses of supplemental iron (45 mg/day or more) may cause gastrointestinal side effects, such as nausea, constipation, dark stools, stomach pain, nausea, and vomiting.

When iron is not bound by ferritin and transferrin, it can create free radicals, which can harm a number of organs, including the liver, blood vessels, colon.

Supplementation can produce nausea, headaches and other symptoms, iron overload is a serious health risk.