Measurement of Zinc Absorption From Meals: Comparison of Extrinsic Zinc Labeling and Independent Measurements of Dietary Zinc Absorption

Sheng, Xia; Hambidge, K. Michael; Miller, Leland V.; Westcott, Jamie E; Lei, Sian; Krebs, Nancy F.

doi:10.1024/0300-9831.79.4.230

Cited by 11 publications

(11 citation statements)

References 20 publications

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“…These latter studies both raised questions in that the methodologies involved quantities of tracer and/or supplemental Zn that constituted a relatively large portion of the total Zn in the test meals. We have recently conducted a study of Zn absorption from whole diets by 21 healthy adult women, which revealed absorption of an extrinsic Zn isotope label and absorption of total Zn in the diets did not differ (P = 0.49) (26). This is consistent with our previous unpublished observations of agreement between Zn absorption measurements using isotopic tracer and metabolic balance methods.…”

Section: Discussionsupporting

confidence: 73%

The Quantity of Zinc Absorbed from Wheat in Adult Women Is Enhanced by Biofortification , ,

Rosado

Hambidge

Miller

et al. 2009

The Journal of Nutrition

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131

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Biofortification of crops that provide major food staples to large, poor rural populations offers an appealing strategy for diminishing public health problems attributable to micronutrient deficiencies. The objective of this first-stage human study was to determine the increase in quantity of zinc (Zn) absorbed achieved by biofortifying wheat with Zn. Secondary objectives included evaluating the magnitude of the measured increases in Zn absorption as a function of dietary Zn and phytate. The biofortified and control wheats were extracted at high (95%) and moderate (80%) levels and Zn and phytate concentrations measured. Adult women with habitual diets high in phytate consumed 300 g of 95 or 80% extracted wheat as tortillas for 2 consecutive days using either biofortified (41 mg Zn/g) or control (24 mg Zn/g) wheat. All meals for the 2-d experiment were extrinsically labeled with Zn stable isotopes and fractional absorption of Zn determined by a dual isotope tracer ratio technique. Zn intake from the biofortified wheat diet was 5.7 mg/d (72%) higher at 95% extraction (P < 0.001) and 2.7 mg/d (68%) higher at 80% extraction compared with the corresponding control wheat (P = 0.007). Zn absorption from biofortified wheat meals was (mean +/- SD) 2.1 +/- 0.7 and 2.0 +/- 0.4 mg/d for 95 and 80% extraction, respectively, both of which were 0.5 mg/d higher than for the corresponding control wheat (P < 0.05). Results were consistent with those predicted by a trivariate model of Zn absorption as a function of dietary Zn and phytate. Potentially valuable increases in Zn absorption can be achieved from biofortification of wheat with Zn.

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Section: Discussionsupporting

confidence: 73%

The Quantity of Zinc Absorbed from Wheat in Adult Women Is Enhanced by Biofortification , ,

Rosado

Hambidge

Miller

et al. 2009

The Journal of Nutrition

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131

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“…Test meals extrinsically labeled (9) with a zinc stable isotope were given for 1 d (study day 1) and with an iron stable isotope for 2 d (study days 1 and 2). Pearl millet was fed daily for a week prior to the metabolic studies, but intake quantities were not recorded.…”

Section: Experimental Design and Methodsmentioning

confidence: 99%

Biofortification of Pearl Millet with Iron and Zinc in a Randomized Controlled Trial Increases Absorption of These Minerals above Physiologic Requirements in Young Children

Kodkany

Bellad

Mahantshetti

et al. 2013

The Journal of Nutrition

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115

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Millet is unusually drought resistant and consequently there is a progressive increase in the use of these grains as a human food staple, especially in large areas of India and sub-Saharan Africa. The purpose of this study was to determine the absorption of iron and zinc from pearl millet biofortified with 2 micronutrients that are typically deficient in nonfortified, plant-based diets globally. The study was undertaken in 40 children aged 2 y in Karnataka, India (n = 21 test/19 controls). Three test meals providing ∼84 ± 17 g dry pearl millet flour were fed on a single day for zinc and 2 d for iron between 0900 and 1600 h. The quantities of zinc and iron absorbed were measured with established stable isotope extrinsic labeling techniques and analyses of duplicate diets. The mean (± SD) quantities of iron absorbed from test and control groups were 0.67 ± 0.48 and 0.23 ± 0.15 mg/d, respectively (P < 0.001). The quantities of zinc absorbed were 0.95 ± 0.47 and 0.67 ± 0.24 mg/d, respectively (P = 0.03). These data did not include absorption of the modest quantities of iron and zinc contained in snacks eaten before and after the 3 test meals. In conclusion, quantities of both iron and zinc absorbed when iron and zinc biofortified pearl millet is fed to children aged 2 y as the major food staple is more than adequate to meet the physiological requirements for these micronutrients.

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“…As additional total diet data are identified and new data are published that include phytate intake, these data have been added to the original data set of 21 to give a current total of 72 data sets (means) (Figure 2) (6,9,17,18,20,22,24). The parameters of the current model have been compared with the corresponding values for the original model ( Table 1) and indicate further improvement in the certainty of the estimates, which include a lower A MAX .…”

Section: Effect Of Dietary Phytate On the Bioavailability Of Ingestedmentioning

confidence: 99%

“…Measurement of fractional absorption of zinc with isotope, typically stable isotope, techniques is essential to determine the quantity of zinc absorbed and the efficiency of zinc absorption of any quantity of ingested zinc. In our experience, extrinsic labeling with zinc stable isotopes provides a reliable technique to determine the absorption of intrinsic zinc from a wide range of total diets (6).…”

Section: Saturation Response Modeling Of Zinc Absorption Datamentioning

confidence: 99%

Zinc bioavailability and homeostasis

Hambidge¹,

Miller²,

Westcott³

et al. 2010

The American Journal of Clinical Nutrition

212

149

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Zinc has earned recognition recently as a micronutrient of outstanding and diverse biological, clinical, and global public health importance. Regulation of absorption by zinc transporters in the enterocyte, together with saturation kinetics of the absorption process into and across the enterocyte, are the principal means by which whole-body zinc homeostasis is maintained. Several physiologic factors, most notably the quantity of zinc ingested, determine the quantity of zinc absorbed and the efficiency of absorption. Other factors are age and the time over which zinc is ingested. Zinc from supplements has not been shown to be absorbed differently from that taken with meals that lack inhibitors of zinc absorption. The principal dietary factor known to impair zinc bioavailability is inositol hexa-(and penta-) phosphate or phytate. Modeling of zinc absorption as a function of dietary zinc and phytate accounts for .80% of the variability in the quantity of zinc absorbed. Fitting the model to new data has resulted in continual improvement in parameter estimates, which currently indicate a maximal absorption in adults of '6 mg Zn/d and that the average estimated dietary requirement doubles with 1000 mg dietary phytate/d. Intestinal excretion of endogenous zinc is regulated in response to recent absorption and to zinc status. The quantitative relation of intestinal excretion of endogenous zinc to zinc absorption is currently considered to be of major importance in the determination of zinc requirements. The effects of phytate on intestinal losses of endogenous zinc merit further investigation but are probably not of the same magnitude as its inhibitory effects on absorption of exogenous zinc.Am J Clin Nutr 2010;91(suppl): 1478S-83S.

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Measurement of Zinc Absorption From Meals: Comparison of Extrinsic Zinc Labeling and Independent Measurements of Dietary Zinc Absorption

Cited by 11 publications

References 20 publications

The Quantity of Zinc Absorbed from Wheat in Adult Women Is Enhanced by Biofortification , ,

The Quantity of Zinc Absorbed from Wheat in Adult Women Is Enhanced by Biofortification , ,

Biofortification of Pearl Millet with Iron and Zinc in a Randomized Controlled Trial Increases Absorption of These Minerals above Physiologic Requirements in Young Children

Zinc bioavailability and homeostasis

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