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Biomedical subjects

J G Reinhold

Publications and source records attributed to J G Reinhold.

12 recordsLinked to original sources
PubMed1991

The Journal of Nutrition, Volume 106, 1976: Decreased absorption of calcium, magnesium, zinc and phosphorus by humans due to increased fiber and phosphorus consumption as wheat bread.

During a 20 day period of high fiber consumption in the form of bread made partly from wheaten wholemeal, two men developed negative balances of calcium, magnesium, zinc and phosphorus due to increased fecal excretion of each element. The fecal losses correlated closely with fecal dry matter and phosphorus. Fecal dry matter, in turn, was directly proportional to fecal fiber excretion. Balances of nitrogen remained positive. Mineral elements were well-utilized by the same subjects during a 20 day period of white bread consumption.

Bread↗
PubMed1986

Retention of iron by rat intestine in vivo as affected by dietary fiber, ascorbate and citrate.

The effects of pH, ascorbate, citrate and dietary fiber on retention of ferrous and ferric iron by jejuno-ileal segments of rat intestine were examined in vivo. Iron was introduced in an isosmotic solution of sodium chloride and dextrose buffered by 2-[bis(2-hydroxyethyl)amino]ethanesulfonic acid (BES) and acetate. Stabilization of the iron solutions was aided by use of iron concentrations less than or equal to 1 microgram/ml injected into the intestine for 10-min periods. Iron retention was optimal over a broad pH range from 5 to 7.8. Inclusion of ascorbic acid in the solution injected (5, 25 or 75 micrograms/ml) did not increase retention of iron in either valence state. A low concentration of sodium citrate (2 mM) had no effect on iron retention, but increasing the concentration to 5 mM released iron from the mucosa. Maize and wheat fibers decreased the retention of ferrous iron by binding and by promoting autoxidation and formation of poorly soluble iron polymers. Bound ferrous iron was released completely at pH below 5. Retention of ferric iron was also lowered in the presence of fiber, presumably as a result of polymerization. Retention of iron by the rat in the absence of ligands was independent of valence state.

Animals↗
PubMed1979

Fiber of the maize tortilla.

Fiber concentrations were measured in maize tortillas and in masa, the lime-treated dough from which they are made, with the aid of Van Soest's methods. Neutral detergent fiber of tortillas was 6.60 +/- 0.98% (mean and SD) and acid detergent fiber 3.75 +/- 0.83% of the dry weight corrected for ash. The hemicellulose fraction was 2.89 +/- 0.94%. Both neutral and acid detergent fiber were significantly higher in tortilla than in masa. The gain in fiber by tortillas during baking is attributed to the formation of browning reaction (Maillard) products resistant to the detergent-containing fiber reagents.

Cellulose↗
PubMed1977

Binding of zinc and iron to wheat bread, wheat bran, and their components.

Wholemeal wheat bread decreases the availability and intestinal absorption of divalent metals. To define this action further, binding of zinc in vitro to a wheat wholemeal bread (Tanok), dephytinized Tanok, and cellulose was determined at pH 5.0 to 7.5. Zinc binding by each was highly pH-dependent and reached a maximum at pH 6.5 to 7.5. Removal of phytate from Tanok did not reduce its binding capability. Wheat bran at pH 6.5 and 6.8 bound 72% of iron (0.5 microgram/ml of solution) and 82.5% of zinc (1.43 microgram/ml solution), respectively. Lignin and two of the hemicellulose fractions of wheat bran and high binding capabilities for zinc (85.6, 87.1, and 82.1%, respectively) whereas a third had a lower zinc-binding capability (38.7%). Binding of zinc to various celluloses and dextrans is also demonstrated. Formation of complexes of these metals with wheat fiber can explain, at least in part, the decreased availability of dietary iron and zinc in wholemeal wheat bread.

Bread↗
PubMed1977

Effects of cellulose added to diets of low and high fiber content upon the metabolism of calcium, magnesium, zinc and phosphorus by man.

Addition of 10 g of cellulose dispersed in 150 g of apple compote to the daily diet with a low fiber content for a 20-day period caused the fecal excretion of calcium and zinc of three men to increase significantly. Balances of both metals became negative and their concentrations in plasma decreased. Magnesium balances became negative in two subjects while phosphorus balance changed to negative in one. In a similar experiment in which the cellulose was added to a fiber-rich diet, fecal excretions of calcium and zinc increased significantly in each of two men and excretion of magnesium in one. Previously negative balances became more negative, and calcium and zinc concentrations decreased in plasma. The dependence of fecal dry weight upon fecal fiber content measured by the acid-detergent method was confirmed. However, increments of dry matter per g of fiber were less fecal fiber concentrations were high. Fecal calcium content correlated significantly with fecal fiber in two subjects, and fecal fiber and zinc in one. No correlations were demonstrated in the subject who apparently digested fiber most effectively. Our findings indicate that high intakes of fiber can explain to a considerable extent the impaired utilization of zinc, calcium, and magnesium among villagers in rural Iran.

Adult↗
PubMed1976

Folate content of Iranian breads and the effect of their fiber content on the intestinal absorption of folic acid.

Folate deficiency is a relatively uncommon disorder in central Iran. In order to explain this finding; the acid content of various Iranian breads was determined, since bread is the staple food in Iran. Tanok, the village wholemeal bread, has an average "free" folate content (without conjugase incubation) of 0.34 mug/g. Sangask and Bazari, leavened breads made from flours of high extraction rates and widely consumed in towns and cities, have aberage "free" folate contents of 0.38 and 0.71 mug/g, respectively. The folate content of these breads are significantly higher than that of white bread from refined flour (0.13 mug/g) or oatmeal bread (0.09 mug/g). Iranian breads also have a high content of indigestible fiber (1.6 to 4.2% of dry weight). Since substances within the bread, such as fiber, may interfere with folate absorption by the small intestine, sequential folate absorption tests (tritiated pterolymonoglutamic acid) were performed in four subjects with meals of increasing fiber content and fasting. No interference with folate absorption was found. Furthermore, in vitro studies did not demonstrate the formation of insoluble complexes between bread fiber and folic acid, which might indicate decreased availability.

Bread↗
PubMed1976

Decreased absorption of calcium, magnesium, zinc and phosphorus by humans due to increased fiber and phosphorus consumption as wheat bread.

During a 20 day period of high fiber consumption in the form of bread made partly from wheaten wholemeal, two men developed negative balances of calcium, magnesium, zinc and phosphorus due to increased fecal excretion of each element. The fecal losses correlated closely with fecal dry matter and phosphorus. Fecal dry matter, in turn, was directly proportional to fecal fiber excretion. Balances of nitrogen remained positive. Mineral elements were well-utilized by the same subjects during a 20-day period of white bread consumption.

Adult↗
PubMed1976

The effects of prolonged consumption of wholemeal bread upon metabolism of calcium, magnesium, zinc and phosphorus of two young American adults.

The ability to adapt to a large daily intake of unleavened bread made from wheaten wholemeals of high extraction rate was examined in two young Americans who had not previously consumed fiber, phytate-, and phosphate-rich bread of this type. Adaptation was evaluated by comparing balances of zinc, calcium, magnesium, and phosphorus for a 12 day period after ten days of bread consumption with those during a similar period after 50 days and also by observing changes in blood composition during this period of bread consumption. Significantly negative balances of zinc, magnesium and phosphorus were observed in the initial period. However, all had become positive or nearly so after 50 days. By contrast, calcium balances which were also negative during the initial period remained negative at the end of the study. Plasma calcium and zinc concentrations had declined to low normal or subnormal values at this time. The failure to overcome the disturbing effects of consumption of wholemeal bread upon calcium metabolism occurred despite daily exposure to sunshine for many hours under conditions favorable for Vitamin D biosynthesis.

Adult↗
PubMed1975

Combined zinc and iron compared with iron supplementation of diets of 6- to 12-year old village schoolchildren in southern Iran.

The effects of supplementation of the diets of 6- to 12-year-old children in a village near Shiraz in Iran with zinc plus iron or iron alone, together with the indispensable amino acids in the form of egg white protein, vitamins, minerals, and corn oil have been evaluated. Initially 48 of 59 children had zinc concentrations below the minimum found in well-nourished persons. Eight months of supplementation with zinc plus iron (20 mg daily of elemental zinc as carbonate and 20 mg ferrous iron as fumarate) failed to stimulate growth or bone development or to bring about an increase in plasma zinc concentrations. However, supplementation with iron in the above amount was associated with an acceleration of growth in height and weight. The persistence of low concentrations of zinc in plasma and the failure of supplemental zinc to stimulate growth are attributed to the poor availability of both dietary and supplemental zinc resulting from sequestering action of fiber and phytate present in large amounts in the unleavened whole meal bread consumed by villagers. In addition, the results suggest that simultaneous administration of iron and zinc supplements may impair utilization of the metals.

Alkaline Phosphatase↗
PubMed1975

Phytate destruction by yeast fermentation in whole wheat meals. Study of high-extraction rate meals.

Destruction of phytate by yeast fermentation is compared in sponges prepared from Iranian whole wheat meals of different extraction rates. Phytate was destroyed rapidly in whole meals of 75 to 85 and 85 to 90 per cent extraction, but destruction was retarded in those of 95 to 100 per cent extraction. Production of acid-soluble phosphorus kept pace with phytate destruction in the two whole meals of lower extraction rates but was delayed with less-than-expected yield in those of 95 to 100 per cent rate. Unleavened whole meal bread contains little acid-soluble phosphorus. Leavened breads made from whole meals of slightly lower extraction rate average five times as much. Since phytate phosphorus appears to remain unavailable in the small intestine in many circumstances, dependece on unleavened whole meal bread may result in critically low intakes of available phosphorus when other sources are lacking in the diet. It is concluded that replacement of the whole meals of 95 to 100 per cent extraction rate, presently the main staple of the diet of rural Iran, by those of somewhat lower rate is an important preliminary to the introduction of leaven and fermentation into village bread-making methods.

Bread↗