The Impact of Tannin Consumption on Iron Bioavailability and Status: A Narrative Review

Abstract

Iron deficiency remains a global health issue, and antinutritional factors, such as tannins, are often cited as contributors to the high prevalence of deficiency. Despite this, tannin-rich diets may have potential beneficial cardiovascular and cancer-fighting properties because of the antioxidant activity of tannins. Furthermore, epidemiologic studies and long-term trials involving participants who consumed diets rich in antinutritional factors, particularly tannins, conflict with single-meal bioavailability studies. The purpose of this narrative review is to determine the effect of tannins on iron bioavailability and status and establish whether adaptation to tannins reduces the antinutritional effects of tannins over time. We also aimed to compare tannins used in iron studies. Common themes related to iron bioavailability and iron status with tannin consumption were collected and collated for summary and synthesis based on models and subjects used. Overall, there was dissonance between iron bioavailability and status in studies. Single-meal studies with hydrolyzable and oligomeric catechin and epicatechin tannins (tea and tannic acid) generally support reductions in bioavailability related to tannin consumption but not consumption of condensed tannin, which are more commonly found in food. Long-term animal model, epidemiologic, and multimeal studies generally do not support changes in iron status related to tannin intake. Studies suggest that long-term tannin consumption may impact iron status in a different manner than single-meal studies or bioavailability iron models predict. Furthermore, iron bioavailability studies that use condensed tannins, which are more commonly consumed, may better predict mealtime iron bioavailability. More research is needed to develop representative antinutritional iron studies and investigate mechanisms underlying the adaptation to tannins and other antinutritional factors that occur over time.

The Effect of Potassium and Sulfur Fertilization on Seed Quality of Faba Bean (Vicia faba L.)

“…The antinutritional effects of tannins include depression of food intake, formation of less digestible tannin-dietary protein complexes, inhibition of digestive enzymes, astringent taste of tannin-rich foods and feeds, and toxicity of absorbed tannin and its metabolites [35]. Some studies report that a tannin-rich diet may have a negative effect on iron absorption and cause its deficiency [36]. However, in recent years, especially in human nutrition, the more interesting fact is that phenolic compounds have strong antioxidant activity and a tannin-rich diet may have potential beneficial cancer-fighting properties [37].The chemical composition of grain legume seeds is primarily determined by genotype.…”

Quality Characteristics of Beef Patties Fortified with Husk Tomato and the Effect on Tannic Acid-Induced Anaemia in Rats

“…Tannic acid is typically used to study the reductions in iron bioavailability and/or lowered iron status in rats. Tannic acid could reduce Fe absorption and deplete the serum and haemoglobin iron concentrations, and it induced severe Fedeficient anaemia [18,37]. Aside from the macronutrients protein and fat, the meat of beef patties contains micronutrients (vitamins, minerals, and antioxidant), as well as higher levels of available haem iron, with additional nonhaem iron (inorganic iron) that are involved in essential metabolic processes [38].…”

STATUS KESEHATAN IKAN LELE (Clarias gariepinus) YANG MENERIMA PAKAN BERSUPLEMEN KOMBINASI DAUN SIRIH (Piper betler leaf), JAMBU BIJI (Psidium guajava leaf), DAN KIPAHIT (Tithonia diversifolia leaf)

“…Pada studi yang melibatkan tannin pada pakan benih Laboe rohita oleh Prusty et al (2007) menyebutkan bahwa penambahan tannin pada pakan hingga 20 g.kg -1 pakan tidak memengaruhi pertumbuhan namun berdampak pada gambaran darah dari ikan yang diuji. Sedangkan konsumsi tannin yang masih terkandung dalam daun teh memberikan dampak pada penurunan penyerapan besi jika dibandingkan hewan uji tikus yang tidak mendapatkan perlakuan (Delimont et al, 2012). Pada ikan diduga terjadi juga respons yang sama saat ikan menerima pakan yang ditambah daun yang mengandung tannin.…”