Review published in Advances in Nutrition finds promising results, but more research is needed

Iron deficiency anemia, the most common type of anemia, develops when the human body does not have enough iron.  As a result, the body cannot produce sufficient healthy red blood cells, which are needed to carry oxygen to fuel the body’s tissues.

According to the Global Burden of Disease Study 2016, iron deficiency anemia is one of main causes of global disability.  If left untreated it can lead to cardiovascular disease.  Among women who are pregnant, iron deficiency anemia can lead to premature as well as low birth-weight babies.  Moreover, iron deficiency anemia among infants and children can lead to delayed growth and development as well as increased susceptibility to infection.

Oral iron supplementation is often used as a first-line treatment for iron deficiency amenia; however, absorption of iron from supplements is highly variable due to the poor solubility of commonly used iron salts.  If iron supplements are taken with meals, certain food components can hinder the iron’s absorption.  In addition, iron supplementation can lead to unpleasant gastrointestinal side effects, such as abdominal pain, constipation and diarrhea, leading many people to stop their iron supplementation regimens.

One possible solution may be prebiotics.  Prebiotics are nondigestible food ingredients that promote the growth of beneficial microorganisms in the intestines.  Evidence from animal and human studies suggests that prebiotics can enhance iron absorption.  In response, Frederike M. D. Husmann et al. conducted a scientific review of 11 human trials to evaluate the strength of the evidence.  The results of their research, “The Effect of Prebiotics on Human Iron Absorption: A Review” were published in Advances in Nutrition, the international review journal of the American Society for Nutrition.

According to the authors, “there are promising findings supporting an enhancing effect of certain prebiotics, but inconsistencies between the studies and results exist.  The most convincing evidence exists for the prebiotics galacto-oligosaccharides and fructo-oligosaccharides combined with the commonly used iron compound ferrous fumarate.”  The authors added that “the absorption enhancing property of prebiotics seems to depend on the type of prebiotic and its dose, the iron compound, duration of intake, population group, and on whether the prebiotic was taken together with the iron compound or was previously fed.”

Most of the studies the authors reviewed investigated iron-deficient, mostly anemic infants or adult women with low iron, but without anemia.  Interestingly, the few studies conducted among healthy individuals did not find an effect of prebiotics on iron absorption.

The limited number of studies that have been conducted to date compounded by the large number of inconsistencies between the studies make it difficult to generate more conclusive results.  The authors have therefore called for more research.  In particular, they believe that research focusing on the mechanisms by which prebiotics enhance iron absorption will help define the optimal combinations and doses.  Ultimately, the authors believe that “the long-term efficacy of a combined iron-prebiotic supplement should be investigated in populations at risk for iron deficiency, taking into consideration other outcomes besides iron status such as gut health, inflammatory status, as well as a potential reduction of iron induced gastrointestinal side effects.”