***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: The effects of different polyphenol-containing beverages on Fe absorption from a bread meal were estimated in adult human subjects from the erythrocyte incorporation of radio-Fe . The test beverages contained different polyphenol structures and were rich in either phenolic acids ( chlorogenic acid in coffee ) , monomeric flavonoids ( herb teas , camomile ( Matricaria recutita L. ) , vervain ( Verbena officinalis L. ) , lime flower ( Tilia cor data Mill . ) , pennyroyal ( Mentha pulegium L. ) and peppermint ( Mentha piperita L. ) , or complex polyphenol polymerization products ( black tea and cocoa ) . All beverages were potent inhibitors of Fe absorption and reduced absorption in a dose-dependent fashion depending on the content of total polyphenols . Compared with a water control meal , beverages containing 20 - 50 mg total polyphenols/serving reduced Fe absorption from the bread meal by 50 - 70 % , whereas beverages containing 100 - 400 mg total polyphenols/serving reduced Fe absorption by 60 - 90 % . Inhibition by black tea was 79 - 94 % , peppermint tea 84 % , pennyroyal 73 % , cocoa 71 % , vervain 59 % , lime flower 52 % and camomile 47 % . At an identical concentration of total polyphenols , black tea was more inhibitory than cocoa , and more inhibitory than herb teas camomile , vervain , lime flower and pennyroyal , but was of equal inhibition to peppermint tea . Adding milk to coffee and tea had little or no influence on their inhibitory nature . Our findings demonstrate that herb teas , as well as black tea , coffee and coca can be potent inhibitors of Fe absorption . This property should be considered when giving dietary advice in relation to Fe nutrition BACKGROUND Short-term measurements of iron absorption are substantially influenced by dietary bioavailability of iron , yet bioavailability negligibly affects serum ferritin in longer , controlled trials . OBJECTIVE Our objective was to test the hypothesis that in men fed diets with high or low iron bioavailability , iron absorption adapts to homeostatically maintain body iron stores . DESIGN Heme- and nonheme-iron absorption from whole diets were measured in 31 healthy men at 0 and 10 wk while the men consumed weighed , 2-d repeating diets with either high or low iron bioavailability for 12 wk . The diets with high and low iron bioavailability contained , respectively , 14.4 and 15.3 mg nonheme Fe/d and 1.8 and 0.1 mg heme Fe/d and had different contents of meat , ascorbic acid , whole grains , legumes , and tea . RESULTS Adaptation occurred with nonheme- but not with heme-iron absorption . Total iron absorption decreased from 0.96 to 0.69 mg/d ( P < 0.05 ) and increased from 0.12 to 0.17 mg/d ( P < 0.05 ) after 10 wk of the high- and low-bioavailability diets , respectively . This partial adaptation reduced the difference in iron bioavailability between the diets from 8- to 4-fold . Serum ferritin was insensitive to diet but fecal ferritin was substantially lower with the low- than the high-bioavailability diet . Erythrocyte incorporation of absorbed iron was inversely associated with serum ferritin . CONCLUSIONS Iron-replete men partially adapted to dietary iron bioavailability and iron absorption from a high-bioavailability diet was reduced to approximately 0.7 mg Fe/d . Short-term measurements of absorption overestimate differences in iron bioavailability between diets OBJECTIVE To determine the effect of phytic acid , tannic acid and pectin on  fasting non-heme iron bioavailability in both the presence and absence of calcium . RESEARCH METHODS Twenty-eight apparently healthy adult females participated in two iron absorption studies using radioactive iron isotopes ( (59)Fe and (55)Fe ) . One group received 5 mg of iron ( as FeSO4 ) alone ( control ) , together with 10 mg of phytic acid , 100 mg of tannic acid and 250 mg of pectin ( study A ) , on different days . The second group received the same iron doses and compounds as the other group , plus 800 mg of calcium ( CaCl2 ) ( study B ) . The compounds were administered after an overnight fast , and no food or beverages were consumed for the following 3h . Iron status and circulating radioactivity were measured in venous blood sample s. RESULTS The geometric means of iron bioavailability ( range±1SD ) for iron alone , iron with phytic acid , iron with tannic acid , and iron with citrus pectin were 25.0 % ( 11.9 - 52.0 ) ; 18.9 % ( 9.9 - 35.8 ) ; 16.8 % ( 8.7 - 32.3 ) ; and 21.1 % ( 10.2 - 43.9 ) , respectively ( repeated- measures ANOVA , p<0.02 ( Dunnett 's post hoc : control vs tannic acid p<0.05 ) . When 800 mg of calcium was added ( study B ) , iron bioavailability was 16.7 % ( 10.1 - 27.5 ) ; 13.2 % ( 7.1 - 24.6 ) ; 14.8 % ( 8.8 - 25.1 ) ; and 12.6 % ( 5.5 - 28.8 ) , respectively ( repeated- measures ANOVA , NS ) . CONCLUSIONS Tannic acid  decreases the fasting bioavailability of non-heme iron , however this effect did not exist in the presence of calcium . No effect was observed by phytic acid or citrus pectin on fasting non-heme iron bioavailability in both the presence and absence of calcium Astringency is one of the major organoleptic properties of food and beverages that are made from plants , such as tea , chocolate , beer , or red wine . This sensation is thought to be due to interactions between tannins and salivary proline‐rich proteins , which are natively unfolded proteins . A human salivary proline‐rich protein , namely IB‐5 , was produced by the recombinant method . Its interactions with a model tannin , epigallocatechin gallate ( EGCG ) , the major flavan‐3‐ol in green tea , were studied here . Circular dichroism experiments showed that IB‐5 presents residual structures ( PPII helices ) when the ionic strength is close to that in saliva . In the presence of these residual structures , IB‐5 undergoes an increase in structural content upon binding to EGCG . NMR data corroborated the presence of preformed structural elements within the protein prior to binding and a partial assignment was proposed , showing partial structuration . TOCSY experiments showed that amino acids that are involved in PPII helices are more likely to interact with EGCG than those in r and om coil regions , as if they were anchorage points for the lig and . The signal from IB‐5 in the DOSY NMR spectrum revealed an increase in polydispersity upon addition of EGCG while the mean hydrodynamic radius remained unchanged . This strongly suggests the formation of IB‐5/EGCG aggregates . © 2009 Wiley Periodicals , Inc. Biopolymers 91 : 745–756 , 2009 Summary Background Green leafy vegetables ( GLV ) are rich sources of β – carotene , iron and other micronutrients . Our in vitro studies have demonstrated good antioxidant potential in GLV . Moreover linkages of GLV intakes with plasma retinol and ascorbic acid were seen in apparently healthy Indians . Aim of the study To investigate the effect of GLV as a natural fortificant of multiple micronutrients through a prospect i ve human trial . Methods Short – term ( 0–4 h ) response ( AUC ) of single dose of 7.9 mg β – carotene and 130 mg ascorbic acid through a spinach – carrot meal against the st and ard meal without GLV plus10 mg β – carotene and 150 mg ascorbic acid tablets was studied in two groups of 4 young volunteers each . In the second trial of 3 weeks ' supplementation , 5 groups of young adults ( n = 40 ) were given either 100 g GLV/day alone or with tablets of vitamin E ( 100 mg/day ) , or C ( 100 mg/day ) or more oil ( 5 g/day ) or non – GLV meal with tablet of β – carotene ( 10 mg/day ) . Hemoglobin ( Hb ) , plasma β – carotene , zinc , vitamin C , glucose , and triglycerides were measured . Results In a postpr and ial response , AUC were comparable in both GLV and st and ard meals for β – carotene and ascorbic acid . In case of triglycerides and glucose AUC the GLV meal showed a better recovery to the baseline value after 4 hours than the st and ard meal . Three weeks ' supplementation of GLV with more oil result ed in significant increase of plasma β – carotene ( 51 % ) and Hb ( 9 % ) . GLV with vitamin E showed a significant increase in plasma β – carotene ( 40 % ) , Hb ( 8 % ) and plasma vitamin C ( 6 % ) . Supplementing β – carotene without GLV  significantly increased Hb ( 11 % ) , plasma zinc ( 14 % ) in addition to β – carotene . Multiple regression analyses weighted for energy intake indicated a significant association of percent increase in Hb with intakes of iron , riboflavin , folic acid , β – carotene , copper , phytate and fiber ( p < 0.01 ) , percent change in plasma zinc with intakes of zinc , β – carotene , vitamin C , riboflavin , copper , iron , and thiamin ( p < 0.01 ) , percent change in vitamin C with intakes of vitamin C , vitamin E , niacin , riboflavin , thiamin , β – carotene , zinc , phytate and fiber ( p < 0.05 ) and percent change in plasma β – carotene with intakes of β – carotene , thiamin , folic acid , zinc , phytate and tannins ( p < 0.05 ) . Conclusion Using 100 g GLV/day with 10 g oil could be a single moderate strategy for supplementation of iron , β – carotene , ascorbic acid and zinc BACKGROUND High phytate ( HP ) consumption is a concern in developing countries because of the high prevalence of iron deficiency in these countries . OBJECTIVE We investigated whether habitual consumption of an HP diet reduces the inhibitory effect of phytate on nonheme-iron absorption . METHODS Thirty-two nonanemic females , 18 - 35 y of age , with normal body mass index but with suboptimal iron stores ( serum ferritin , ≤30 μg/L ) , were matched for serum ferritin concentration and r and omly assigned to HP and low-phytate ( LP ) groups , in a parallel design study . Each subject consumed HP or LP foods with at least 2 of their daily meals for 8 wk , result ing in a change in phytate intake ( from 718 to 1190 mg/d in the HP group and 623 to 385 mg/d in the LP group ) . The serum iron response over 4 h after a test meal containing 350 mg of phytate was measured at baseline and postintervention . Ferritin , transferrin receptor , and hepcidin concentrations were measured at baseline and 8 wk . RESULTS Twenty-eight subjects completed the study ( n = 14 per group ) . The serum iron response to the test meal increased in the HP group at postintervention , result ing in a 41 % increase in the area under the curve ( AUC ; P < 0.0001 ) . However , no effect was observed in the LP group ( 21 % decrease in AUC ; P = 0.76 ) . The postintervention serum iron response was lower ( P < 0.0001 ) in the LP group than in the HP group after controlling for the baseline serum iron response and hepcidin concentration , reflecting in a 64 % lower AUC . CONCLUSIONS We found that habitual consumption of an HP diet can reduce the negative effect of phytate on nonheme-iron absorption among young women with suboptimal iron stores . Future studies are needed to explore possible mechanisms . This trial was registered at clinical trials.gov as NCT02370940 To explore the influence of dietary factors of iron  bioavailability and socio-demographic conditions on blood iron status of married adolescent girls ( MAG ) , a cross-sectional study was conducted in 173 MAG ( 15–19 years old ) from urban slums near Pune city , India .  Diet was assessed by two r and om 24-h recalls . The age , weight , height , education , family size , income , physical work , and number of days of menstrual loss were recorded . Fasting blood was analyzed for hemoglobin and serum ferritin . Mean intakes of micronutrients were 40–75 % less than the recommended dietary intakes for Indian adolescent girls . High 
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Common themes that positively influenced tannin-PRP binding included specificity of tannin-PRP binding , PRP and tannin stereochemistry .
Hydrolyzable tannins have different affinities than condensed tannins when binding to PRPs .
Conclusions In vitro modeling suggests that tannins favor PRP binding over iron chelation throughout digestion .
Hydrolyzable tannins are not representative of tannin impact on non-heme iron bioavailability in food tannins because of their unique structural properties and PRP affinities .
With tannin consumption , PRP production is increased , and may be an initial line of defense against tannin-non-heme iron chelation in vivo .