Assessment of zinc bioavailability: studies in rats on zinc absorption from wheat using radio- and stable isotopes

Fox, T E; Fairweather‐Tait, Susan J.; Eagles, John M.; Wharf, S G

doi:10.1079/bjn19940114

Cited by 13 publications

(5 citation statements)

References 25 publications

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“…Published studies comparing absorption of intrinsic and extrinsic Zn isotope tracers have provided inconclusive results. Six reports of such studies in rats demonstrated either no significant difference or that the extrinsic tracer was absorbed to a greater or lesser extent (14)(15)(16)(17)(18)(19). Of 6 studies in humans, 4 found no significant difference, whereas 2 studies indicated that the extrinsic label was absorbed at a lower level (20)(21)(22)(23)(24)(25).…”

Section: Discussionmentioning

confidence: 98%

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

Rosado

Hambidge

Miller

et al. 2009

The Journal of Nutrition

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: Discussionmentioning

confidence: 98%

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

Rosado

Hambidge

Miller

et al. 2009

The Journal of Nutrition

131

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“…Many studies have been performed to validate the extrinsic labelling approach, in particular for Zn, with contradictory results. Even if it is still not certain that the isotope behaves in exactly the same way as the native Cu or Zn bound in the food matrix (Fairweather-Tait et al 1991;Fox et al 1994;Boza et al 1995), it is accepted that extrinsic labels may be used as an approximate guide when assessing the bioavailability of Cu and Zn from different regimens.…”

Section: Discussionmentioning

confidence: 99%

Response of diamine oxidase and other plasma copper biomarkers to various dietary copper intakes in the rat and evaluation of copper absorption with a stable isotope

Feillet‐Coudray¹,

Coudray²,

Bayle³

et al. 2000

Br J Nutr

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There is a lack of agreement on index of Cu status and reliable and sensitive biomarkers are still required. The purpose of this present work was to assess in rats the sensitivity of diamine oxidase (DAO) activity, a recently proposed biomarker, to modifications in dietary Cu intake in comparison with other plasma biomarkers of Cu status. We also evaluated the effect of Cu dietary level on Cu and Zn intestinal absorption. Results showed that plasma Cu and plasma caeruloplasmin were significantly decreased at day 8 compared with the control group (7·4 mg Cu/kg diet) while DAO activity was significantly decreased at day 12 of the deficient diet (0·61 mg Cu/kg diet). Cu supplementation (35 mg Cu/kg diet) had no effect on any of the studied biomarkers of Cu status. In Cu-deficient rats plasma Cu and DAO activities were normalized 4 d after return to the control diet while caeruloplasmin was normalized later, at day 11. Apparent absorption values (%) of total Cu or 65Cu isotope were significantly increased in the Cu-deficient rats compared with the other groups and similar in the control and the Cu-supplemented groups. The urinary excretion of total Cu or 65Cu isotope were increased in the Cu-supplemented group compared with the other two groups. Both apparent absorption and urinary excretion of total Zn or 67Zn isotope remained unchanged in the three experimental groups. In conclusion, DAO activity seemed to be less sensitive to Cu deficiency than plasma Cu or caeruloplasmin concentrations. The present study also showed a significant increase in Cu intestinal absorption with dietary Cu restriction but no decrease with Cu supplementation in the rat.

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“…Rapidly and almost fully absorbed (about 79 %) in upper part of the gastrointestinal tract of rats fed free compound (601) Small-intestinal phytases have high activity in rats and very much lower activity in human subjects and pigs (217) Fe: 1 -20 % in human subjects fed usual diets (204) Mg: 70 % in rats fed whole-wheat flour (219) 21 -28 % in human subjects fed brown bread diet (602) 50 % in human subjects fed a typical diet (603) 57·6 % in human subjects fed a standard diet (604) Zn: 16·6 % in human subjects consuming wholemeal bread (605) 20 % in adult women consuming whole-wheat tortillas (606) 35 % in rats fed whole-wheat flour (219) 88·9 -94·6 % in rats fed whole-wheat flour (607) 18·5 % in rats fed wheatmeal (608) 60 -82 % in rats fed whole-grain wheat (609) 30 -37 % in rats fed whole-wheat flour chapatti (610) Cu: 62 -85 % in human subjects fed whole-wheat bread (611) 16·3 -16·5 % in rats fed free compound (71,73) Se: 81·1 -84·5 % in rats fed whole-wheat flour (607) 73 -86 % in rats fed whole wheat as compared with sodium selenite (612) 100 % in rats fed whole-wheat flour as compared with sodium selenite (613) P: 41-55 % in human subjects fed brown bread diet (602) Ca: 81·7 % in human subjects fed whole-wheat bread (614) 43 -44 % in rats fed whole-wheat flour chapatti (610) 85·7 -92·8 % in rats fed whole-wheat flour (607) Thiamin (vitamin B 1 ): 91 % in rats fed whole-wheat bread compared with free thiamine mononitrate (100 %)…”

Section: Appendixmentioning

confidence: 99%

New hypotheses for the health-protective mechanisms of whole-grain cereals: what is beyond fibre?

2010

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Epidemiological studies have clearly shown that whole-grain cereals can protect against obesity, diabetes, CVD and cancers. The specific effects of food structure (increased satiety, reduced transit time and glycaemic response), fibre (improved faecal bulking and satiety, viscosity and SCFA production, and/or reduced glycaemic response) and Mg (better glycaemic homeostasis through increased insulin secretion), together with the antioxidant and anti-carcinogenic properties of numerous bioactive compounds, especially those in the bran and germ (minerals, trace elements, vitamins, carotenoids, polyphenols and alkylresorcinols), are today well-recognised mechanisms in this protection. Recent findings, the exhaustive listing of bioactive compounds found in whole-grain wheat, their content in whole-grain, bran and germ fractions and their estimated bioavailability, have led to new hypotheses. The involvement of polyphenols in cell signalling and gene regulation, and of sulfur compounds, lignin and phytic acid should be considered in antioxidant protection. Whole-grain wheat is also a rich source of methyl donors and lipotropes (methionine, betaine, choline, inositol and folates) that may be involved in cardiovascular and/or hepatic protection, lipid metabolism and DNA methylation. Potential protective effects of bound phenolic acids within the colon, of the B-complex vitamins on the nervous system and mental health, of oligosaccharides as prebiotics, of compounds associated with skeleton health, and of other compounds such as a-linolenic acid, policosanol, melatonin, phytosterols and para-aminobenzoic acid also deserve to be studied in more depth. Finally, benefits of nutrigenomics to study complex physiological effects of the 'whole-grain package', and the most promising ways for improving the nutritional quality of cereal products are discussed. Whole-grain wheat: Bioactive compounds: Physiological mechanisms: Health IntroductionThere is growing evidence that whole-grain cereal products protect against the development of chronic diseases. The most important of these in terms of public health are obesity (1,2) , the metabolic syndrome (3,4) , type 2 diabetes (5,6) , CVD (7) and cancers (8 -12) . Whole-grain cereal consumption has also been shown to be protective against mortality, as was shown with inflammation-related death (i.e. noncardiovascular and non-cancer inflammatory diseases such as, for example, respiratory system diseases) (13) and with cancer and CVD (4,14,15) . These conclusions are supported by the effects of consuming refined cereal products (bread, pasta and rice), as these have been associated with an increased risk of digestive tract, pharynx, larynx and thyroid cancers in northern Italians (16) . However, an association between a lower risk of developing a chronic disease and a high whole-grain cereal consumption does not mean a direct causal relationship and provides no information about the physiological mechanisms involved.These metabolic diseases are related to our daily lifestyle, no...

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Assessment of zinc bioavailability: studies in rats on zinc absorption from wheat using radio- and stable isotopes

Cited by 13 publications

References 25 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 , ,

Response of diamine oxidase and other plasma copper biomarkers to various dietary copper intakes in the rat and evaluation of copper absorption with a stable isotope

New hypotheses for the health-protective mechanisms of whole-grain cereals: what is beyond fibre?

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