Iron Deficiency & Brain Function

Prevalence of Iron Deficiency & Consequences on Brain Function


JUN 1975 – James D. Cook, MD and Clement A. Finch, MD, Seattle, WA

Iron Nutrition

“The interface between ingested iron and body iron resides in the mucosal cell of the upper small intestine. By controlling entry of iron into the body, the intestinal mucosa determines the amount of total body iron. This portal of entry is not specific for iron but is apparently shared by and can be competitively inhibited by a variety of heavy metals including cobalt, manganese and zinc – but not copper or magnesium.”

“Ascorbic acid is a potent enhancer of iron absorption, not only because of its ability to reduce iron, but also by forming a chelate with ferric iron at low pH which remains soluble at the higher pH of the duodenum.”

“For example, 60 mg of ascorbic acid added to a meal of rice more than tripled absorption of iron, and 150 grams of papaya containing 66 mg of ascorbic acid increased iron absorption more than five fold when taken with a meal of maize.”

“Phosphates are known to impair iron absorption by the formation of insoluble complexes of iron within the duodenum. This is particularly true of phytate, illustrated by the pronounced inhibition of iron absorption by bran present in whole wheat bread.”

“As yet, studies of these dietary factors have not progressed sufficiently to define their relative importance in the American diet.”

“A similar line of reasoning may be applied to the iron deficiency observed in domesticated animals, such as pigs and wild animals held in captivity.”

Summary statement: “It would seem that changes of civilization have confronted man with a dietary intake of iron inconsistent with his previously established genetic makeup. While improving the iron nutrition of the population seems a worthy cause, its success will depend on further studies of food iron availability and on careful evaluation of the effectiveness of those dietary changes which are undertaken.”


SEP 1989 – Dr. L. Hallberg, University of Göteborg, Sweden

Search for Nutritional Confounding Factors in the Relationship between Iron Deficiency and Brain Function

“Possible dietary confounders: 1) low intake of ascorbic acid, 2) excess of phytates, and 3) increased absorption of lead.”

“An iron deficiency may be accompanied by a zinc deficiency, which may affect mental performance.”

Summary statement: “A state of iron deficiency may increase the absorption of lead from the diet, which in turn may also affect brain function.”


JAN 1999 – University of Göteborg, Sweden

Prediction of Dietary Iron Absorption [the search for an accurate model for calculating bioavailability of dietary iron]

“It is well known that the variation in dietary iron absorption from meals is due more to differences in the bioavailability of the iron, which can lead to a more than 10-fold variation in iron absorption, than to a variation in iron content.”

“In several studies it was observed that soy protein reduced the fraction of iron absorbed from a meal. The high content of phytate in soy products led the researchers to suspect that the inhibition by soy might be related to phytate. Reduction of the phytate content by repeated washings with acidic solutions, however, did not totally abolish the inhibition.”

Summary statement: [An accurate algorithm was not determined due to the multitude of contributing and varying factors] “The lack of knowledge of the presence of different factors in different foods is even more obvious when the algorithm is applied to diets in developing countries.”


APR 2000 – University of Texas Medical Branch, Galveston, TX

Causes of Iron and Zinc Deficiencies and Their Effects on Brain

“Low consumption of foods rich in bioavailable iron and zinc such as meat, particularly red meat, and high consumption of foods rich in inhibitors of iron and zinc absorption, such as phytate, certain dietary fibers and calcium, cause iron and zinc deficiencies. Neuropsychological impairment is one of several potential outcomes of these deficiencies.”

“Ascorbic acid has no beneficial effect on Zn retention.”

“Humans are unable to compensate for the inhibitory effects of phytate.”

“The phytate content of foods is not currently listed in the publicly available USDA databases.”

“Impaired neuropsychologic function is one of the adverse effects of severe Fe and Zn deficiencies.”

“Non-heme Fe concentrations in brain and the number of dopamine D2 receptors are decreased by Fe deficiency in experimental animals, and learning is decreased.”

“Acute Zn deficiency impairs electrophysiology and behavior of rats. Zn deficiency during early brain development causes malformations. Zn deficiency during later brain development impairs neuronal growth and synaptogenesis, and causes behavioral sequellae.”

Summary statement: “Fe and Zn deficiencies are common and can occur simultaneously. Mild-to-moderate deficiencies impair neuropsychologic function.”


FEB 2009 – Department of Biology, King College, Bristol, TN

A Chronic Iron-Deficient/High-Manganese Diet in Rodents Results in Increased Brain Oxidative Stress and Behavioral Deficits in the Morris Water Maze

“Iron deficiency is especially common in pregnant women and may even persist following childbirth. This is of concern in light of reports demonstrating that iron deficiency may be sufficient to produce homeostatic dysregulation of other metals, including manganese.”

Summary statement: “Taken together, our data suggest that vulnerable iron-deficient populations exposed to high levels of manganese may indeed be at risk of potentially dangerous alterations in brain metal levels which could also lead to behavioral deficits.”