Comparative evaluation of green and black tea consumption on the iron status of omnivorous and vegetarian people

Schlesier, K.; Kühn, B.; Kiehntopf, Michael; Winnefeld, K; Roskos, Martin; Bitsch, Roland; Böhm, Volker

doi:10.1016/j.foodres.2011.06.019

Cited by 13 publications

(14 citation statements)

References 20 publications

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“…Supplementation periods consisted of week 0 and week 4 meal challenges, with 4 wk of tannin supplementation in between ( Figure 2 ). Four-week supplementation periods were chosen as completed previously ( 31 ) to assess for iron status changes with inhibited iron absorption at each meal and to allow for time to adapt to tannins. Each participant consumed a powdered, condensed tannin (Grape seed extract, 95% condensed proanthocyanidins; NuSci, Walnut, California) supplement mixed in an opaque bottle with water and a noncaloric flavor enhancer and sweetener (MiO Original) to improve its palatability, 3 times/d for 4 wk.…”

Section: Methodsmentioning

confidence: 99%

Long-Term Dose-Response Condensed Tannin Supplementation Does Not Affect Iron Status or Bioavailability

Delimont

Fiorentino

Kimmel

et al. 2017

Current Developments in Nutrition

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Background: Repeated phytic acid consumption leads to iron absorption adaptation but, to the best of our knowledge, the impact of repeated tannin consumption has not yet been established. Salivary proline-rich proteins (PRPs) may improve iron absorption by precipitating tannins. Objectives: This study aimed to determine the effect of long-term, dose-response condensed tannin supplementation on iron bioavailability and status and to assess the effect of salivary proteins on iron bioavailability during prolonged condensed tannin consumption. A secondary objective was to assess astringency as a potential marker for adaptation to tannins and iron bioavailability. Methods: Eleven nonanemic women were enrolled in a double-blind 3-dose crossover trial. Three (1.5, 0.25, or 0.03 g) condensed tannin supplements were consumed 3 times/d for 4 wk in random order, with 2-wk washouts in between. Meal challenges were employed before and after supplementation to assess iron bioavailability, iron status, salivary PRP changes, and astringency. Results: Tannin supplementation in any dose did not change iron bioavailability at any dose (P > 0.82) from weeks 0 to 4. Hemoglobin (P = 0.126) and serum ferritin (P = 0.83) were unchanged by tannin dose from weeks 0 to 4. There were significant correlations among tannin supplementation and iron bioavailability, basic proline-rich proteins (bPRPs) (r = 0.366, P = 0.003), and cystatin production (r = 0.27, P = 0.03). Astringency ratings did not change significantly within or between tannin doses (P > 0.126), but there were negative relations among bPRP (r < −0.32, P < 0.21), cystatin production (r < −0.2, P < 0.28), and astringency ratings. Conclusions: Condensed tannin consumption did not affect iron bioavailability or status regardless of the supplementation period in premenopausal nonanemic women. Correlation analyses suggest that bPRPs and cystatins are associated with improved iron bioavailability and that lower ratings of astringency may predict improved iron absorption with repeated tannin consumption.

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Section: Methodsmentioning

confidence: 99%

Long-Term Dose-Response Condensed Tannin Supplementation Does Not Affect Iron Status or Bioavailability

Delimont

Fiorentino

Kimmel

et al. 2017

Current Developments in Nutrition

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“…Fundamental nexus between nutrition and health diverting the consumers focus towards plant based natural products as a remedy against various metabolic syndromes. In diet based regimen, functional/nutraceutical foods are gaining core attention of the nutritionists to be a therapeutic device against the maladies [ 2 ]. No doubt, medicines are inevitable for curing various physiological disorders nevertheless, high treatment cost predominantly in the developing countries along with associated side effects demanding some other rationale approaches to meet the perils.…”

Section: Introductionmentioning

confidence: 99%

Exploring the potential of black tea based flavonoids against hyperlipidemia related disorders

et al. 2018

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BackgroundIn recent decade, Hyperlipidemia related disorders like obesity, hypercholesterolemia and diabetes are considered as the leading killers for mankind. Fundamental nexus between nutrition and health diverting the consumers focus towards plant based natural products as a remedy against various metabolic syndrome. Considering this, present study was conducted to explicate the role of black tea polyphenols such as Theaflavins and thearubigins therapeutic potential to tackle targeted maladies especially oxidative stress related disorders like hypercholesterolemia and diabetes.MethodsThe mandate of current investigation was to explore the hypoglycemic and hypocholestrolemic perspective of isolated theaflavin and thearubigins through a model feeding trial. For the purpose, theaflavin & thearubigins were isolated from black tea through solvent partition method and utilize to form three types of nutraceutical drinks (theaflavin, thearubigins & theaflavin + thearubigins based) alongside control to be further utilized in bioefficacy trial. In bioefficacy trial, three types of independent studies were design on the bases of diet by involving 20 male wistar rats in each study (5 for each group). In study I, normal diet was administrated while, in study II & III high cholesterol and high sucrose diet was given, respectively along with prepared nutraceutical drinks to synchronize their therapeutic effect for a period of 56 days. At the termination of trial, Feed & drink intakes, body weight, total cholesterol, LDL, HDL, triglycerides, glucose and insulin levels were measured.ResultsThe results indicated reduction in cholesterol, LDL and triglycerides levels of experimental rats in all studies with significant increase in HDL. In this context, theaflavin based drink imparted maximum reduction in cholesterol (3.75, 11.03 & 10.39%), LDL (3.84, 14.25& 10.84%) & triglycerides (2.99, 8.54 & 6.65%) in respective studies compared to thearubigins and theaflavin + thearubigins based drinks. However, theaflavin+ thearubigins based drink caused highest glucose decline and maximum insulin increase in all studies as compared to other nutraceutical drinks. The reported value for the insulin increase were 13.02 ± 1.02 & 14.55 ± 1.13, 10.09 ± 0.15 & 11.59 ± 0.86 for Hyperglycemic and Hypocholestrolemic rats respectively compared to control (7.84 ± 0.45 & 9.10 ± 0.41) for study I and II.ConclusionsIn the nutshell, theaflavin and thearubigins based dietary interventions are helpful to alleviate the hypercholestrolemia and hyperglycemia and should be promoted as parallel therapy to combat these disorders.

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“…In 19- to 32-y-old German vegetarian ( n = 6 and 8 in black and green tea groups, respectively) and omnivorous ( n = 10, both groups) men and women who consumed green or black tea for 4 wk, ferritin was significantly decreased in omnivorous women who consumed black tea, as well as in a subgroup analysis of anemic women who consumed black or green tea. There were no changes in ferritin in men and nonanemic vegetarian women who consumed tea, nor did total iron binding capacity, hemoglobin, serum iron, or hematocrit change in groups from baseline to end line ( 69 ). In a study that compared the iron status of Indian men and women aged 20–25 y ( n = 46), polyphenol-rich diets that contained leafy green vegetable supplements did not significantly affect individuals' hemoglobin concentrations after 3 wk of supplementation compared with those consuming a control meal with no leafy green vegetables ( 70 ).…”

Section: Resultsmentioning

confidence: 91%

“…In epidemiologic studies, tannin compounds that inhibit iron bioavailability in single-meal studies were not correlated with iron status changes ( 55 ) or iron deficiency ( 53 , 54 ). Furthermore, studies lasting ≥4 wk that focused on tannin-rich foods did not find alterations in iron status ( 69 , 70 ). Some animal ( 38 , 48 ) and human ( 40 , 41 ) studies that were reviewed point instead to the idea of long-term adaptation to antinutritional factors, including tannins.…”

Section: Discussionmentioning

confidence: 99%

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

Delimont

Haub

Lindshield

2017

Current Developments in Nutrition

104

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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.

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Comparative evaluation of green and black tea consumption on the iron status of omnivorous and vegetarian people

Cited by 13 publications

References 20 publications

Long-Term Dose-Response Condensed Tannin Supplementation Does Not Affect Iron Status or Bioavailability

Long-Term Dose-Response Condensed Tannin Supplementation Does Not Affect Iron Status or Bioavailability

Exploring the potential of black tea based flavonoids against hyperlipidemia related disorders

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

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