Molar Ratios Of Phytate Research Articles

The role of zinc and vitamin A in persistent diarrhea among infants and young children.

The role of zinc and vitamin A in persistent diarrhea among infants and young children.

Zinc absorption, mineral balance, and blood lipids in women consuming controlled lactoovovegetarian and omnivorous diets for 8 wk

Zinc absorption, mineral balance, and blood lipid concentrations were measured in 21 women aged 33 +/- 7 y (range: 20-42 y) consuming controlled lactoovovegetarian and nonvegetarian diets for 8 wk each in a crossover design. The lactoovovegetarian and nonvegetarian diets, respectively, provided (by analysis) 973 and 995 mg Ca, 1.8 and 1.3 mg Cu, 367 and 260 mg Mg, 5.9 and 2.5 mg Mn, 1457 and 1667 mg P, 9.1 and 11.1 mg Zn, and (by calculation) 40 and 16 g dietary fiber, 2.5 and 0.8 mmol phytic acid, molar ratios of phytate to Zn of 14 and 5, and millimolar ratios of (phytate x Ca) to Zn of 344 and 111. Dietary zinc absorption was measured by extrinsic isotopic labeling and whole-body counting. Plasma cholesterol, cholesterol fractions, and lipoproteins were reduced 7-12% with the lactoovovegetarian diet, consistent with predictions based on dietary cholesterol and fat. Blood pressure was unaffected. Calcium, copper, magnesium, and phosphorus balances were not different between diets; manganese balance tended to be greater with the lactoovovegetarian diet (P < 0.07). The lactoovovegetarian diet was associated with a 21% reduction in absorptive efficiency that, together with a 14% reduction in dietary zinc, reduced the amount of zinc absorbed by 35% (2.4 compared with 3.7 mg/d) and reduced plasma zinc by 5% within the normal range. Zinc balance was maintained with both diets. Although there is a greater risk of zinc deficiency in persons consuming lactoovovegetarian compared with omnivorous diets, with inclusion of whole grains and legumes zinc requirements can be met and zinc balance maintained.

The Zinc, Calcium, Copper, Manganese, Nonstarch Polysaccharide and Phytate Content of Seventy-Eight Locally Grown and Prepared African Foods

Suboptimal mineral nutrition may be prevalent in Africa; however, research is limited by the absence of reliable data on the mineral, dietary fiber and phytate content of local foods. For this reason, 75 Ghanaian foods and 3 Malawian cereal flours were analyzed for Zn, Ca, Cu, and Mn by atomic absorption spectrophotometry, nonstarch polysaccharide (NSP) was analyzed by the Englyst method, and phytic acid was analyzed using ion-exchange procedures; some foods were analyzed using the HPLC method. On a fresh weight basis (mg/100 g FW), legumes and animal products had the highest mineral content ranging from 1.2 to 8.5 (Zn), 49 to 4638 (Ca), 0.15 to 1.49 (Cu) and 0.06 to 2.67 (Mn), for animal products; and from 0.4 to 6.0 (Zn), 10 to 442 (Ca), 0.08 to 1.47 (Cu), and 0.28 to 14.12 (Mn) for legumes. In contrast, cereals had the lowest Ca and Cu content, ranging from 1.3 to 16 and from 0.01 to 0.19 (mg/100 g FW), respectively; roots, tubers, plantain, and vegetables had the lowest Zn content (0.1–0.9 mg/100 g FW). The NSP content of groundnuts and bean cakes (mg/ 100 g FW), and the phytate content of cereals and legumes (g/100 g FW) were higher than those of other plant foods (for NSP, 5.8–6.3 vs 0.2–4.6 for other plant foods; and for phytate, 66–279 for cereals; and 118–339 for legumes vs 0–118 for other plant foods). For cereal flours, over 90% of the inositol phosphates were inositol hexa- and pentaphosphates, compared to less than 65% in the fermented cereal products. The molar ratios of phytate:Zn (P:Z) of the cereal staples and most of the starchy staples were similar despite the higher phytate content of the former (8:34; for cereals vs 4:24 for cassava products and yams). Hence, decreasing the proportion of cereals to starchy staples would probably not improve the bioavailability of Zn. However, the addition of groundnuts, fermented locust bean seeds (dawadawa), or fermented kapok seeds (kangtong) to soups and stews, and the use of small fish would increase the mineral content of these dishes.

Development of a dietary model for the study of mild zinc deficiency In humans and evaluation of some biochemical and functional Indices of zinc status

After a 1-wk baseline period, a dietary regimen was developed to induce mild zinc deficiency in 15 males (aged 25.3 +/- 3.3 y, mean +/- SD). The regimen consisted of 1 wk on a liquid diet containing 0.6 mg Zn/d and molar ratios of phytate to zinc (phy:Zn) and of phytate X calcium to zinc [(phy X Ca): Zn] of 209 and 4116, respectively, followed by 6 wk on a diet based on soy protein and egg albumin containing 4 mg Zn/d and with phy:Zn and (Ca X phy):Zn of 70 and 2000, respectively. Subjects were then repleted with 30 mg Zn/d for 2 wk. Fasting blood and urine samples were taken weekly. Changes were observed in mean plasma (mumol/L) and urinary zinc (mumol/d): baseline 97.0 +/- 10.9 and 8.0 +/- 2.7, depletion 80.1 +/- 13.4 and 4.3 +/- 2.3, and repletion 100.8 +/- 13.6 and 8.2 +/- 3.1, respectively (P less than 0.05); taste acuity (0.05 less than P less than 0.10); and cellular immune responses (P less than 0.05). Activities of plasma angiotensin-1-converting enzyme and acidic alpha-D-mannosidase were unchanged. Mild zinc deficiency was induced by the dietary regimen.

Binding differences of Zn(II) and Cu(II) ions with phytate

Binding differences have been observed between Zn(II) ions and Cu(II) ions with phytate. In pH 7.00 solutions containing 10 mM phytate, 1 mM Cu(II) or Zn(II) ions, and 0–0.15 M NaCl, all of the Cu(II) ions were bound by phytate as soluble species, whereas an insoluble zinc phytate complex slowly precipitated from solution. More phytate precipitated after 3 hr from zinc phytate solutions of higher ionic strength than from the solutions of lower ionic strength. After 48 hr, the ionic strength of the zinc phytate solution did not affect the amount of phytate precipitated. The zinc: phytate molar ratio in the precipitates collected after 3 hr was 4:1. This binding ratio decreased to 3.5:1 in precipitates collected after 24 and 48 hr. Chemical shift changes in the 31P NMR spectra of pH 7.00 phytate and zinc phytate solutions, as functions of ionic strength, provided an explanation for these observations. Arguments are presented to support the proposition that Zn(II) ions preferentially bind the 5 axial/1 equatorial phytate conformer in pH 7.00 solutions containing 10 mM phytate and 1 mM Zn(II) ions.

NMR and ESR studies of interactions among divalent cations, phytic acid, and N-acetyl-amino acids

Ion-selective electrode potentiometry, 13C and 31P nuclear magnetic resonance (NMR) and electron spin resonance (ESR) techniques have been utilized to study the independent and mutual interactions of divalent cations (zinc, copper, and calcium ions), phytic acid, and N-acetylhistidine or N-acetylglutamate. In pH 7.00 copper phytate and calcium phytate solutions (1 mM divalent cation, 10 mM phytate), the preferential phytate binding sites for calcium and copper(II) ions appear to be the P5 phosphate group, or between the P5 phosphate group and the P4 or P6 phosphate groups, with the phytate molecule in the 5 equatorial/1 axial conformation. An insoluble zinc phytate complex with a 4:1 zinc ion:phytate molar ratio slowly precipitated from the pH 7.00 zinc phytate solution (1 mM zinc ions, 10 mM phytate). Soluble ternary complexes involving phytate, N-acetylhistidine, and calcium, copper(II), or zinc ions may exist at pH 7.00. There was no evidence of ternary phytate-divalent cation-N-acetylglutamate complexes existing at pH 7.00.

Dietary calcium, phytate, and zinc intakes and the calcium, phytate, and zinc molar ratios of the diets of a selected group of East African children

Dietary zinc, calcium, and phytate intakes of 66 rural Malawian children aged 4-6 y were determined during three seasons on the basis of weighed food records and analyzed food composition data. Height and weight measurements were also recorded and hair samples were collected for zinc analysis. Seasonal daily zinc, calcium, and phytate intakes of females ranged from 6.2 +/- 1.7 to 6.8 +/- 2.1 mg (mean +/- SD), from 335 +/- 170 to 401 +/- 257 mg, and from 1621 +/- 660 to 1729 +/- 592 mg, respectively and, for males, 7.0 +/- 1.7 to 8.0 +/- 2.3 mg, 342 +/- 164 to 473 +/- 310 mg, and 1857 +/- 530 to 2161 +/- 684 mg, respectively. Cereals provided greater than 42% of dietary zinc. Seasonal mean molar ratios of phytate to Zn and Ca x phytate to Zn [per 1000 kcal (4.2 MJ)] and the median Ca to phytate molar ratio ranged from 24 to 27, 151 to 188 mmol/1000 kcal (4.2 MJ), and 3.1 to 3.4, respectively. Over 78% of the children consumed diets with phytate-to-Zn and Ca x phytate.Zn-1 . 1000 kcal-1 molar ratios above values suggested to jeopardize zinc status. Correlations between hair zinc, phytate-to-Zn, and Ca x phytate.Zn-1 . 1000 kcal-1 molar ratios suggest that high phytic acid intakes may compromise zinc status in these children.

Phytate, zinc, and calcium contents of 30 East African foods and their calculated phytate:Zn, Ca:phytate, and [Ca][phytate]/[Zn] molar ratios

Representative samples of 30 staple Malawian foods, raw and prepared “as eaten,” were analyzed for phytate using an anion-exchange method, and for calcium and zinc by flame atomic absorption spectrophotometry. Phytic acid contents expressed on a fresh weight (FW) basis ranged from 211–1089 mg/100 g for cereals and 166–1297 mg/100 g for legumes, to 4–97 mg/100 g for leaves, 10–59 mg/100 g for roots, and 11–25 mg/100 g for fruits. In general, leaves had the highest calcium content (81–514 mg/100 g FW), followed by kidney beans (90 mg/100 g FW), and dry pigeon peas (112 mg/100 g FW). The calcium content of other foods analyzed was relatively low. The zinc content of wild blight, cassava leaves, and okra leaves was comparable to that for the less refined cereals and legumes (i.e., > 1.0 mg/100 g FW), but higher than that of highly refined cereals, pumpkin leaves, chinese cabbage, and other foods analysed (i.e., < 1.0 mg/100 g FW). Cooking had no effect on the phytate content of cereals, but milling and fermentation reduced both the phytate and zinc contents of maize flour. The phytate:Zn molar ratios calculated for all cereals and most legumes analyzed were greater than 20:1. Corresponding Ca:phytate molar ratios were low. Fruits, except for mangoes, vegetables, and roots, had low phytate: Zn molar ratios, but their Ca:phytate and [Ca][phytate]/[Zn] molar ratios were high. Mangoes had high phytate:Zn, Ca:phytate, and [Ca][phytate]/[Zn] molar ratios. These analytical results suggest that the bioavailability of zinc in the Malawian diet is probably low, due to the high phytic acid content of the staple foods.

The phytate and mineral content of some cereals, cereal products, legumes, legume products, snack bars, and nuts available in New Zealand

Analyses for phytate by an indirect precipitation method and for the minerals calcium (Ca), zinc (Zn), iron (Fe), copper (Cu), and manganese (Mn) by atomic absorption spectrophotometry were carried out on 100 foods available in New Zealand. Foods with 1% phytate (dry weight basis) included untoasted muesli, rolled oats, wheat germ, wheat bran, soybean, and some soy products. Most breads contained between 0.35 and 0.60% phytate; legumes on average had 0.62% phytate, as did snack bars. There was a wide variation in Ca and Zn contents: There was a tenfold variation in Ca content among the legume products, whereas there was a seventyfold variation in Zn content among the cereals. The phytate: Zn molar ratio, which is presumed to indicate the biovailability of Zn, was above 20∶1 for two-thirds of the cereals and almost all of the snack bars; it was above 15∶1 for one-third of the breads, almost all of the legumes, and half of the legume products. These high phytate: Zn molar ratios, as well as some Ca: phytate molar ratios above 6∶1, indicate that there might be a reduced biovailability of Zn in many of the foods analyzed in this study.

A ready-to-use kit for the preparation of99mTc-phytate for liver scanning

Kits were developed-for the sterile labelling of phytate with99mTc. The effect of molar ratio of phytate to stannous chloride, pH, dilution of the Sn-phytate with99mTc-generator eluate, time of incubation, the shelf life of99mTc-phytate and the storage time of Sn-phytate on the labelling yield of phytate with99mTc was investigated using paper chromatography and gel chromatography column scanning method (GCS). Organ distribution was performed in rabbits and mice. Excellent human liver scans were obtained.

99 mTc]Ca-Phytate: Some colloidal characteristics related to the optimal preparation conditions

Some physico-chemical characteristics of the colloidal radiopharmaceutical [ 99 m Tc]Ca-phytate related to optimal preparation conditions have been studied. (1,2) It is demonstrated that the Ca 2+-phytate stoichiometry is 6:1. Two different Ca-phytate colloids seem to be formed, mainly depending on the Ca 2+:phytate molar ratio-one of low mycelar size for a 1:1 Ca 2+:phytate molar ratio ( cmc ∗ = 5.10 −5 M) , and another one, with a higher mycelar size for a 6:1 molar ratio (cmc = 8.10 −5 M). This last one it probably better for providing a good quality splenic uptake.

Iranian Flat Breads: Relative Bioavailability of Zinc

ABSTRACTThe effect of flour extraction rate, type and length of fermentation and baking conditions on relative bioavailability of zinc of five distinctly different Iranian flat breads and their unfermented doughs, was determined using weanling rats fed low (5.5 ppm) levels of dietary zinc. When breads rather than unfermented doughs were used for preparation of diets, with one exception, bioavailability of Zn significantly (P &lt; 0.05) improved. Rats on the barbari‐bread‐based diet showed the highest weight gain and femur zinc content. There was no significant difference in weight gain among rats on dough‐based diets. High correlation of weight gain and femur zinc with feed intake and low or no correlation with fiber or Zn:phytate molar ratio of the diets was observed.