Article

Reduction of the Phytate Content of Bran by Leavening in Bread and Its Effect on Zinc-Absorption in Man

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Abstract

1. The effect of leavening of bread containing bran on the phytic acid content and on zinc absorption in man was studied. 2. Twenty breads with leavening times varying from 0 to 120 h were prepared. The breads contained 250 g wheat bran/kg flour. The phytic acid content was determined after baking. 3. The phytic acid content of bread containing bran was reduced to about 40% after 2 h of leavening and to 15 % after 2 d. No further decrease was observed. 4. Zn absorption from single meals was determined using a radioisotope technique. Forty-two students volunteered for these studies. They were served a breakfast of milk, butter, bread and 10, 16 or 30 g bran served either raw or baked into the bread with fermentation times of 15 min, 45 min, 3 h or 16 h. One meal contained no bran, but phytate and Zn were added in amounts equivalent to the content of 10 g bran. 5. The amount and percentage of Zn absorbed increased at each bran level as fermentation was prolonged. The percentage of Zn absorbed was reduced by increased bran content in the meal. 6. It is concluded that the fermentation of bread containing bran reduces the phytic acid content and increases Zn absorption from such bread. This may be of importance to people subjected to diets with a high cereal content, especially in combination with a low animal-protein intake.

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... Actually, tetraphosphates and triphosphates were described to have little impact on zinc absorption, whereas inositol hexaphosphates and pentaphosphates severely impaired intestinal zinc availability in in vivo studies [153,157,158]. Nevertheless, phytate can be hydrolyzed by phytase, which is an enzyme that degrades the molecule to tetraphosphates and triphosphates, consequently increasing zinc availability [159,160]. In contrast to sheep and pigs, which are able to degrade phytate with their own intestinal phytase, levels of this enzyme in human small intestine are very low and, thus, phytate degradation is highly dependent on phytogenic and microbiotic phytase [153,159,161,162]. ...
... In contrast to sheep and pigs, which are able to degrade phytate with their own intestinal phytase, levels of this enzyme in human small intestine are very low and, thus, phytate degradation is highly dependent on phytogenic and microbiotic phytase [153,159,161,162]. Phytogenic phytase, particularly in grains, can be activated during fermentation and food processing [159,160,163], which, subsequently, enhances zinc absorption [163]. ...
... However, calcium does not increase the phytate-mediated inhibition of zinc absorption in several human dietary studies [77,166,175]. Other than phytate, fibers such as cellulose seem to have no significant impact on zinc absorption [160,170]. Dietary protein levels positively correlate with zinc uptake [77,154]. Human zinc absorption is substantially higher in the presence of protein from animal sources than plant-based protein [181] and the addition of animal protein to vegetable-based food significantly improved its zinc bioavailability in vivo [182]. ...
Article
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Zinc absorption in the small intestine is one of the main mechanisms regulating the systemic homeostasis of this essential trace element. This review summarizes the key aspects of human zinc homeostasis and distribution. In particular, current knowledge on human intestinal zinc absorption and the influence of diet-derived factors on bioaccessibility and bioavailability as well as intrinsic luminal and basolateral factors with an impact on zinc uptake are discussed. Their investigation is increasingly performed using in vitro cellular intestinal models, which are continually being refined and keep gaining importance for studying zinc uptake and transport via the human intestinal epithelium. The vast majority of these models is based on the human intestinal cell line Caco-2 in combination with other relevant components of the intestinal epithelium, such as mucin-secreting goblet cells and in vitro digestion models, and applying improved compositions of apical and basolateral media to mimic the in vivo situation as closely as possible. Particular emphasis is placed on summarizing previous applications as well as key results of these models, comparing their results to data obtained in humans, and discussing their advantages and limitations.
... Wholemeal cereal flours provide significant amounts of nutrients such as carbohydrate, protein, vitamin, minerals including the trace elements, but also contain high levels of phytic acid (myo-inositolhexakisphosphate, InsP6) that inhibits the bioavailability of essential minerals such as iron and zinc (Hallberg et al., 1989;Nävert et al., 1985). As a result, iron deficiency anaemia is highly prevalent in many low-income countries where cereals constitute the major staple food (Taylor et al., 1995;Tatala et al., 1998;Hurrell et al., 2002). ...
... Cereals do also contain phytase, an enzyme that degrades the phytate content and as a result may free the minerals making them available for absorption by humans (Hurrell, 2004). However, the inhibiting effect of phytate occurs at very low phytate concentrations and to improve iron absorption, the phytate content needs to be degraded to a phytate:iron molar ratio <1 , and for an improved zinc absorption the phytate:zinc molar ratio needs to be <15 (Nävert et al., 1985;Hunt, 2003). The phytase activity of cereal grains varies greatly with rye and wheat showing high activities while maize, millet and sorghum have low activities (Egli et al., 2002;Azeke et al., 2011). ...
... It has been suggested that a phytate:Fe molar ratio of 1:1 and preferably below a 0.4:1 molar ratio needs to be achieved for a 2-fold increase in iron absorption [10]. To achieve an improved zinc bioavailability from cereal based foods the phytate:zinc molar ratio needs to be lower than 15 [11,12]. A long term and sustainable approach to combat iron deficiency anaemia could therefore be to efficiently apply phytate reducing techniques in the bread making process. ...
... The composite flour bread prepared with soaked sorghum flour with added P. kudriavzevii TY13 resulted in a bread with a phytate:iron molar ratio of 0.1 and a phytate:zinc ratio of 0.18, which is by far below the suggested threshold ratios for improved iron and zinc absorption in humans [10,11,12]. The composite flour bread (Table 2) prepared with soaked sorghum flour without TY13 had about 94% phytate reduction. ...
Article
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Whole sorghum flour is rich in phytate, which strongly binds minerals preventing their absorption by humans. Diets based on whole sorghum has therefore been associated with high prevalence of iron and zinc deficiencies in low-income countries. To improve iron absorption, the phytate content needs to be degraded to a phytate:iron molar ratio <1, and for an improved zinc absorption, a phytate:zinc molar ratio <15. Our study aims at finding conditions which effectively reduce the phytate content in whole flour composite bread. The means that was applied included activation of endogenous sorghum phytase and addition of high-phytase secreting yeast Pichia kudriavzevii TY13 at optimal pH in the baking process as well as in a pre-soaking step of the whole sorghum flour. The phytate content was analysed using high performance ion chromatography (HPIC). The initial phytate content in the composite flour was 5.3 µmol/g, that was reduced to 0.85 µmol/g in the composite bread after fermentation for 2
... He observed that at molar ratios above the range of 6-10, zinc absorption starts to decline and at ratios above 15, absorption is typically less than 15 percent. Nävert et al. (1985) and Sandström and Sandberg (1992) reported that phytate present in foods can be reduced by activating the phytase or through the addition of microbial or fungal phytases. The activated phytase hydrolyses the phytate to lower inositol phosphates, resulting in improved zinc absorption (Nävert et al., 1985;Sandström and Sandberg 1992). ...
... Nävert et al. (1985) and Sandström and Sandberg (1992) reported that phytate present in foods can be reduced by activating the phytase or through the addition of microbial or fungal phytases. The activated phytase hydrolyses the phytate to lower inositol phosphates, resulting in improved zinc absorption (Nävert et al., 1985;Sandström and Sandberg 1992). ...
... For instance, a risk of developing iron deficiency has been highlighted among phytic acid rich foods (Coulibaly, Kouakou, and Chen 2010). According to Nävert, Sandström, and Cederblad (1985), this is 60% more magnesium and 20% more zinc that could be absorbed when phytic acid is removed from food. Also, as seen in section 6.2 of this review, calcium absorption is inhibited in the intestine by strong complexation with phytic acid (Foisnet 2020). ...
Article
Nowadays, legumes are considered as a good source of plant-based proteins to replace animal ones. They are more favorable regarding environmental aspects and health benefits, therefore many people consider moving toward a greener diet. Interestingly, recent consumer trends are promoting pea and faba bean as alternatives to soybean. Both are rich in protein and a good source of essential nutrients and minerals (calcium). However, these advantages can be partially impaired due to their high phytic acid content. This natural polyphosphate is a major antinutrient in plant-based foods, as it can bind minerals (particularly calcium) and proteins, thereby reducing their digestibility and subsequent bioavailability. Indeed, complexes formed are insoluble and limiting the absorption of nutrients, thus lowering the nutritional value of pulses. To understand and overcome these issues, the present review will refine specific mechanisms involved in assemblies between these three essential compounds in legumes as soluble/insoluble binary or ternary complexes. Molecular interactions are influenced by the environmental medium including pH, ionic strength and molar concentrations modulating the stability of these complexes during protein extraction. Protein/phytic acid/calcium complexes stability is of high relevance for food processing affecting not only structure but also functional and nutritional properties of proteins in legume-based foods.
... However, its phytate/mineral molar ratio was affected significantly between samples. The absorption of minerals (Fe, Zn, and Ca) from a meal corresponds directly to its phytate content [44][45][46]. The phytate/minerals molar ratios are used to predict its inhibitory effect on the bioavailability of minerals [47]. ...
Article
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Injera is Ethiopian traditional fermented flatbread which is made mostly from tef flour. Tef grain is milled and the flour kneaded to have batter-like dough which will ferment before injera baking. The influence of mill type: hammer mill (HM), disc mill (DM) and blade mill (BM) and mechanical kneading speed-time combinations (K1, K5, and K9) on fermentation kinetics was investigated. Phytate to mineral molar ratio (Fe, Zn and Ca) of tef injera was also investigated as affected by mill type and different kneading conditions. In both milling and kneading levels, maltose was the highest sugar concentration initially, followed by glucose and fructose. As fermentation continued, a similar trend in maltose breakdown was seen among HM, DM, and BM. However, different patterns of glucose and fructose breakdown were seen on HM than DM and BM. Similarly, HM had a different pattern in increment of lactic acid concentration than DM and BM. Similar trend in maltose concentration was seen between K1, K5, and K9. Again glucose breakdown and the increment of lactic acid in K9 were different than that of K1 and K5. Phytate/mineral molar ratio of BM was significantly different (p<0.05) from HM and DM. There was also a significant difference (p<0.05) in phytate/mineral molar ratio between K1, K5, and K9. Decreased phytate/mineral molar ratio was seen with increasing of kneading speed (rpm) for a longer period of time. The effect of mill type and kneading speed and time combinations on fermentation kinetics and phytate/mineral molar ratio were significant.
... Various other dietary constituents may either enhance or impair zinc absorption, Phytate and indigestible fibre which are present in plant foods form insoluble complexes with zinc in the intestinal lumen, and are generally considered to be the primary factors responsible for the poorer absorbability of zinc from plant proteins and cereal products than from foods of animal origin (Reinhold et a 1, 1976;Ismail-Beigi et a 1 , 1977;Kies et al, 1979;Solomons, 1982;Navert et al , 1985). Animal experiments have shown that copper and cadmium may reduce the uptake of (Evans et al , 1974), and zinc absorption may also be impaired by tin (Johnson et al, 1981a) and ...
... In developing countries where staple food is mainly seed-based, it leads to serious alimentary deficiencies in humans 3 . Non-ruminant animals are unable to digest phytic acid, and the undigested phytic acid promotes water eutrophication and environmental pollution 6 . This warrants the development of low phytic acid crops 7 . ...
... The inhibitory effect of PA to iron and zinc absorption is known to follow a dose dependent relationship (Hallberg et al., 1989;Nävert and Sandström, 1985). The inhibitory effect of phytate seems to be stronger for iron compared to zinc, and results in a significant negative effect on iron absorption when 2-10 mg phytate phosphorus is present, while for zinc, negative effects are seen from contents of 50 mg phytate phosphorus onwards (Lönnerdal, 2002). ...
Thesis
Cereals contribute to a substantial proportion of the iron and zinc requirements of low income groups yet they are of low iron and zinc content and bioaccessibility (proportion of minerals available for absorption) due to their high level of mineral binding compounds. Fermentation is commonly practiced for the preparation of cereal products in developing countries and has potential to improve iron and zinc bioaccessibility through the reduction of mineral binding compounds. The purpose of this PhD was to evaluate the potential of fermentation to improve the iron and zinc bioaccessibility of cereal based complementary porridges commonly consumed in Zimbabwe and Africa at large. Finger millet porridges fermented at the household level were of low iron and zinc content and bioaccessibility which could not meet more than 50% of the dietary requirements of children between the ages of 1-3 years. Fermented cereals from five locations in Zimbabwe showed differences in both mineral contents and bioaccessibility that could be attributed to varietal and agricultural influences. Presence of soil iron on some cereals from Chiweshe and Chiredzi could improve the nutritional status of populations subsisting on such cereals. Of interest was the low zinc content and bioaccessibility on all cereals despite their origin suggesting the probable existence of a higher risk of zinc deficiency than iron. Food-to-food fortification using local ingredients such as baobab fruit pulp and mopane worm coupled with cereal fermentation could improve mineral nutrition in developing countries.
... These plant foods are high in phytic acid, which is a potent inhibitor of Zn absorption. 31 ...
Article
This paper reviews the possibility and limits for increasing the content and bioavailability of iron (Fe), zinc (Zn) and calcium (Ca) in edible parts of staple crops, such as cereals, pulses, roots and tubers as a way to combat mineral deficiencies in human populations. Theoretically, this could be achieved by increasing the total level of Fe, Zn and Ca in the plant foods, while at the same time increasing the concentration of compounds which promote their uptake (ascorbic acid), and/or by decreasing the concentration of compounds which inhibit their absorption (phytic acid or phenolic compounds). The content of Zn and Ca in grains and fruits can in some cases be increased through soil and/or foliar applications of Zn and Ca fertilisers. Plant breeding and genetic engineering techniques, however, have the greatest potential to increase Fe and Zn content in grains, roots and tubers. The possibility of enhancing Ca and ascorbic acid content in plant foods by plant breeding and genetic engineering remained to be explored. The critical factor is to ensure that the extra minerals have an adequate bioavailability for man. Given the important role of phytic acid and polyphenols in plant physiology, reducing the levels of these compounds in the edible parts of plants does not appear to be wise although introduction of phytases which are active during digestion is an exciting possibility.
... Although Hurrell et al. (1992) indicated that a strong inhibitory effect of phytate on iron exists even when the [phytate]: [iron] molar ratio is as low as 0.2, the critical value of the [phytate]: [iron] molar ratio of < 1.0 is accepted as phytate begins to lose its inhibitory effect on iron absorption at this level (Hurrell, 2004). Zinc absorption is also a dose-dependent response (Nävert & Sandström, 1985) and poor availability of zinc is encountered when the molar ratio of [phytate]: [zinc] is > 15 (Sandberg, Anderson, Carlesson, & Sandström, 1987). In a study by Hunt and Beiseigel (2009), the amount of zinc absorbed from a 1-day diet was reduced by 25% (1 mg) when the [phytate]: [zinc] molar ratio was increased from 4 to 15. Ellis et al. (1987) recommended a ≤10 [phytate]: [zinc] molar ratio for adequate zinc bioavailability. ...
Article
Cassava, rice, and banana flours were used individually to replace wheat flour in cereal-legume-based composite flours. The proximate composition, mineral content, antinutritional effect, mineral molar ratios, and aflatoxin level were investigated. Replacing wheat flour with rice flour significantly (P < 0.05) improved protein, fat, potassium, and phosphorus content in samples. The molar ratios of phytate or oxalate to minerals (calcium and zinc) in all composite flours were lower than the reported critical values, except phytate to iron. However, all samples, except full replacement by rice flour, might not provide adequate zinc bioavailability when the effect of calcium and phytate on zinc absorption was collectively considered. Although all composite flours were contaminated with aflatoxins, only the control composed of wheat flour did not meet the EU regulatory threshold (4.0 μg/kg) for total aflatoxins. The findings showed that nutritional properties and aflatoxin content of composite flours can be improved by replacement with local crops.
... Compared to PI, ASP was a better source of Mn and Zn containing approximately 10-and 2.5-fold higher amounts of these elements, respectively (Table 3). Although fiber is often implied to negatively affect zinc bioavailability, more precise studies involving reduction of concomitant antinutrient factors (Barbro et al., 1985) as well as experiments on pure fiber components such as α-cellulose (Turnlund et al., 1984) suggested little or no inhibitory effect of fiber on zinc absorption. However, further investigation should be performed to evaluate the influence of the high fiber content in ASP on manganese bioavailability (Freeland-Graves et al., 2015). ...
Article
Full-text available
Protein-rich products, prepared from industrial rapeseed meal, have the potential for versatile applications in the food, feed, and nutraceutical industries. The aim of study was to characterize the biochemical composition of two protein-rich products obtained from industrially produced rapeseed meal. Protein isolate (PI) and acid soluble protein (ASP) were prepared by alkaline extraction (pH 12.0) followed by isoelectric precipitation (pH 4.5). Biochemical analyses revealed that PI contained a high protein amount (86.9%), while ASP had 28.8% protein and a relatively high level of non- protein compounds including ash (20.6%) and fiber (30.0%). Results showed that neither protein products contained glucosinolates. They were rich in microelements; the most abundant were Cu (64.3 mg kg⁻¹) and Fe (133 mg kg⁻¹) in PI and Mn (39.7 mg kg⁻¹) and Zn (84.2 mg kg⁻¹) in ASP. PI and ASP were also a good source of Se (1.1 mg kg⁻¹ and 0.9 mg kg⁻¹, respectively). Lysine was the most abundant essential amino acid in PI with amino acid score of 100.7% followed by leucine (98.3%) and valine (95.8%). Both protein products were mainly composed of low molecular weight fractions (5 to 33 kDa), but in different ratio. The PI contained two fractions with molecular weights 53 and 235 kDa which were not found in ASP. In conclusion, PI and ASP exhibited different biochemical characteristics which make them suitable for different applications.
... A study by Reinhold and coworkers on phytate rich diet found that phytate has inhibitory effect on Zn absorption [68]. Several subsequent single meal studies clearly showed a negative correlation between presence of phytate or ionositol phosphates and zinc absorption in humans [69][70][71][72]. In another study by Bohn and coworkers on 20 human volunteers (10 males and 10 females) it was found that fractional magnesium absorption from white bread was significantly impaired by addition of phytic acid. ...
Article
Mankind has been using plants and natural products since time immemorial for fighting the menace of heavy metal toxicity both in humans as well as in environment surrounding them. Nearly thirty five metals have been reported to cause occupational or accidental exposure to humans. Amongst these, twenty three are heavy metals. The increasing use of such heavy metals including radionuclides constitutes deleterious health issues. Presence of heavy metals in environment and their subsequent effects on humans down the food chain creates potential health hazard. Therefore removal of heavy metal has been a subject of paramount importance. Results of an exhaustive literature survey of natural and plant based compounds against heavy metal pollution including patents, books and scientific data from globally accepted scientific databases and search engines (Pubmed, Scopus and Web of Science, Sci Finder and Google Scholar), is systematically reviewed. It is conceived that a number of phytochemical agents as well microorganism can act as heavy metal removing agent both from human beings and the environment surrounding. Microbes which are used for the removal of heavy metals from the water bodies include bacteria, fungi, algae and yeast. Some important antioxidants such as flavonoids, pectin and phytic acid are also used for the elimination of the heavy metals from the human body. The present article is an extensive review that will offer a number of strategies and possible mechanisms for the heavy metals removal both from environment as well as from human body.
... In addition, the strong chelating characteristic of phytic acid reduces the bioavailability of other essential dietary nutrients such as minerals, trace elements (e.g., Ca ), proteins, and amino acids (3)(4)(5). In human nutrition, phytic acid is reported to inhibit absorption of iron, zinc, and calcium and can cause nutritional deficiencies in populations in developing countries (6)(7)(8). Animal feeds with a high phytic acid content are generally supplemented with inorganic phosphate; however, this causes increased fecal phosphate levels and subsequent eutrophication of waterways. Supplementation of animal feeds with commercial phytases is an increasingly popular alternative and reduces the associated environmental issues caused by inorganic phosphate supplementation (9). ...
Article
Full-text available
Phytic acid, or myo-inositol hexakisphosphate, is the primary source of inositol and storage phosphorus in plant seeds and has considerable nutritional importance. In this form, phosphorus is unavailable for absorption by monogastric animals, and the strong chelating characteristic of phytic acid reduces the bioavailability of multivalent minerals such as iron, zinc, and calcium. Currently, there is no simple quantitative method for phytic acid; existing methods are complex, and the most commonly accepted method, AOAC Official MethodSM 986.11, has limitations. The aim of this work was to develop and validate a simple, high-throughput method for the measurement of total phosphorus and phytic acid in foods and animal feeds. The method described here involves acid extraction of phytic acid, followed by dephosphorylation with phytase and alkaline phosphatase. The phosphate released from phytic acid is measured using a modified colorimetric molybdenum blue assay and calculated as total phosphorus or phytic acid content of the original sample. The method was validated to a maximum linearity of 3.0 g phytic acid/100 g sample. Accuracy ranged from 98 to 105% using pure phytic acid and from 97 to 115% for spiked samples. Repeatability ranged from 0.81 to 2.32%, and intermediate precision was 2.27%.
... The inhibitory effect of PA to iron and zinc absorption is known to follow a dosedependent relationship. (40,41) The inhibitory effect of PA seems to be stronger for iron compared to zinc and results in a significant negative effect on iron absorption when 2-10 mg phytate phosphorus is present, while for zinc, negative effects are seen from contents of 50 mg phytate phosphorus onward. (42) Therefore, molar ratios are used to predict mineral absorptions. ...
Article
Many weaning and complementary foods in Africa are plant based thus are not good sources of bioavailable iron and zinc owing to the presence of anti-nutritional factors, in particular phytic acid, phenolic compounds and to some extent dietary fiber. Several strategies are being developed to increase levels of bioavailable iron and zinc in plant based diets. These strategies range from fortification, biofortification, dietary diversification and use of household processing methods such as soaking, cooking, germination and fermentation. Fermentation poses a great potential as a significant amount of these foods in Africa involve a natural fermentation step. Exploration of this process could offer a more economical and sustainable way to reduce iron and zinc binders and consequently increase the bioavailability of the minerals in diets consisting of fermented cereals.
... Turnlund et al (2), using levels of phytic acid similar to those found in whole grain and cereal-based diets, observed a significantly reduced absorption of zinc with a liquid formula diet. Similar decreases in zinc absorption were observed when phytic acid was added to white bread (17) and to cow's milk formula (18) at levels close to those observed for wholemeal bread and soy-based formula, respectively. ...
Article
Full-text available
The body requires certain levels of essential nutrients, such as zinc, to maintain life. Intake less than the required levels can cause impaired function, disease and death. Every essential nutrient has a unique range of tissue concentration and intake necessary for proper physiological and biochemical functioning. Many criteria have been used to set dietary intake levels for nutrients. For trace elements, however, a limited number of investigative approaches are currently employed by researchers due to inadequate information F on individual requirements and intake levels. Further, a clear lack of satisfactory biochemical methods to measure zinc nutritional status continues to hinder formulation of dietary guidelines. Thus, many assumptions have to be made, and large safety margins have to be added to assumed daily requirements in order to compensate for this absence of information. Numerous barriers to a full understanding of what constitutes an adequate dietary recommendation for zinc still exist. Zinc is incompletely absorbed, and this absorption can be greatly influenced by the chemical form in which zinc is bound; interactions with other nutrients also affect absorption. Part three of this five-part review presents the current Canadian recommended nutrient intakes for zinc for various sex and age categories and provides a rationale for the suggested values. The important nutrient interactions that affect the bioavailability of zinc, including those with phytates, copper, cadmium, tin anal iron, are discussed.
... 6,102,103 Phytic acid strongly inhibits the absorption of iron and other essential minerals. 3,69,97,104,105 It interferes with the functions of essential nutrients, so is considered a natural antinutrient substance. 106 The intake of PA relates negatively with the glycemic index of normal individuals. ...
Article
Mineral balance is of significant importance to achieve sound health in humans. Scarcity, overdose, or discrepancies of minerals have a negative effect on bodily fitness. However, the amount of a mineral consumed is not the most important factor in maintaining a balance; this, rather, is the amount that is bioavailable. Micronutrient malnutrition is a serious threat to more than 2 billion people worldwide, even though it is preventable to a large extent. Deficiencies of micronutrients such as calcium, iron, and zinc can cause various disorders - for example, osteoporosis, anemia, and development of a defective immune system, respectively. Wheat contains significant amounts of Ca, Fe, Zn, and other minerals. Wheat and wheat products can contribute significantly to the dietary intake of minerals, but the limiting factor is the presence of high amounts of phytic acid. In order to overcome malnutrition, it is necessary to find different ways to reduce the inhibitory effect of phytic acid on minerals.
... Fibre is often implicated in antagonising zinc, although this is due to the high phytate content of most fibre containing foods. Fibre itself has little effect on zinc absorption [73]. The consumption of tea, coffee may also affect absorption via containing tannins which bind with zinc, forming insoluble complexes [74]. ...
Article
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Appropriate physiological functioning requires optimal nutrition, which needs to be in balance to prevent potential detrimental interactions, especially when administered at pharmacological dosages. Many nutrients function in harmony to complement digestive function and assimilation. Some may hinder these processes and compete for uptake, while others may also be required in tandem to assist in metabolism which may ultimately affect a number biochemical cycles.Many similar synergistic and antagonistic functions exist within human physiology and should be considered, particularly in the health and research arenas, where positive outcomes may be more likely if nutrient preparations are formulated with assistant supplementary nutrients, while nutrient related confounders need also to be accounted for. A variety of these are discussed in detail, with emphasis on relationships in health and disease.
... The phytate content can be reduced by activating the phytase present in most phytate-containing foods or through the addition of microbial or fungal phytases. Phytases hydrolyse the phytate to lower inositol phosphates, resulting in improved zinc absorption (Navert et al., 1985;Sandström and Sandberg, 1992). The activity of phytases in tropical cereals such as maize and sorghum is lower than that in wheat and rye. ...
... A previous study by Knudsen, et al. [49] observed that high fiber-containing diets decreased the absorption of zinc. Barbro, et al. [50] reported that leavening bread improved zinc absorption to a concentration similar to low fiber bread, indicating that fiber has a little or no impact on the absorption of zinc [51]. Therefore, the effect of fiber on zinc bioavailability may depend on the type of fiber, fiber composition, and the animal or human subjects used. ...
Article
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Studies on dietary fiber and nutrient bioavailability have gained an increasing interest in both human and animal nutrition. Questions are increasingly being asked regarding the faith of nutrient components such as proteins, minerals, vitamins, and lipids after feed formulation. The aim of this review is to evaluate the evidence with the perspective of fiber usage in feed formulation. The consumption of dietary fiber may affect the absorption of nutrients in different ways. The physicochemical factors of dietary fiber, such as fermentation, bulking ability, binding ability, viscosity and gel formation, water-holding capacity and solubility affect nutrient absorption. The dietary fiber intake influences the different methods in which nutrients are absorbed. The increase in the total fiber content of the diet may delay the glycemic response. Soluble fiber decreased blood glucose content whereas purified insoluble fiber has a little or no effect on the blood glucose levels after a meal. Dietary fiber and prebiotics influence the host animal well-being by regulating blood glucose or insulin levels, stool bulking effects, increasing the acidity of the gut, constructive synthesis of short chain fatty acids (SCFAs), decreasing intestinal transit time, stimulating the growth of intestinal microbes, and increasing blood parameters. Previous studies suggest that fiber affects the bioavailability of nutrients, and maintains the host wellness.
... A large part of our global population tends to suffer from mineral (mainly, iron and zinc) deficiencies due to the ingestion of phytate rich plant diets (Bentley et al., 1997;Tatala et al., 1998). Studies in humans have conclusively shown that iron and zinc absorption from a meal corresponds inversely to its phytate content (Nävert et al., 1985). The dietary phytase gets inactivated during cooking, resulting in poor phytate digestion that affects mineral absorption in the small intestine. ...
Chapter
Across the world, plant products, especially of cereals and legumes, are the major staple food and feed sources for humans and animals. The seeds and grains contain phytic acid, the major repository form of organic phosphorus, which is not digestible by monogastrics and acts as an antinutrient. Phytases are a group of hydrolytic enzymes that catalyze stepwise removal of soluble phosphate from phytates, thus making it available to monogastrics. Among microbes, fungi are predominant phytase producers. This review focuses on multifarious applications of fungal phytases as food and animal feed additives, in aquaculture, plant growth promotion, soil amendment, environmental protection and as therapeutics.
... During fermentation, the LAB and yeast in sourdough, i.e., Lb. brevis, S. diasticus, S. cerevisiae and Lb. fermentum produce the enzyme phytase which neutralise phytic acid thus free up these digestive enzyme to allow more effective digestion [29][30][31]. A recent screening of 152 LAB isolated from cereal-based substrates revealed a widespread capacity of the isolates (95%) for degrading phytic acid with strains of Lb. brevis LD65 and Lb. ...
Article
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Sourdough is the oldest form of leavened bread used as early as 2000 BC by the ancient Egyptians. It may have been discovered by accident when wild yeast drifted into dough that had been left out resulting in fermentation of good microorganisms, which made bread with better flavour and texture. The discovery was continued where sourdough was produced as a means of reducing wastage with little known (at that point of time) beneficial effects to health. With the progress and advent of science and technology in nutrition, sourdough fermentation is now known to possess many desirable attributes in terms of health benefits. It has become the focus of attention and practice in modern healthy eating lifestyles when linked to the secret of good health. The sourdough starter is an excellent habitat where natural and wild yeast plus beneficial bacteria grow by ingesting only water and flour. As each sourdough starter is unique, with different activities, populations and interactions of yeast and bacteria due to different ingredients, environment, fermentation time and its carbohydrate fermentation pattern, there is no exact elucidation on the complete make-up of the sourdough microbiome. Some lactic acid bacteria (LAB) strains that are part of the sourdough starter are considered as probiotics which have great potential for improving gastrointestinal health. Hence, from a wide literature surveyed, this paper gives an overview of microbial communities found in different sourdough starters. This review also provides a systematic analysis that identifies, categorises and compares these microbes in the effort of linking them to specific functions, particularly to unlock their health benefits.
... Cook et al. [152] reported that because of the high phytate content of cereal porridges, iron absorption of native iron and fortification iron might be deficient. Barbro et al. [153] reported that when the phytate is absent zinc absorption rate from our food will increase by 20 percent and magnesium absorption will increase by 60 percent. ...
Preprint
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Wheat is the essential constituent of cereal-based diets and one of the most significant sources of calories. However, there is an inherently low bioavailability of proteins, mineral, and vitamins in modern wheat grains. Biofortification has earned recognition as an outstanding approach, at the same time as a cure for world hunger. The developments in the identifications of quantitative trait loci (QTL) analysis and understanding of the physiological and molecular basis of QTLs controlling the biofortification traits in wheat has revealed new horizons for the improvement of modern wheat varieties. Within this review, we have compiled the information from the studies carried out in wheat using QTL mapping methodologies that is among the best methods for biofortification traits. We hope this review will serve as an essential reference for the QTLs identified for the several important biofortification traits in wheat.
... Zinc deficiency may contribute to the burden of anemia by altering erythropoiesis in the bone marrow or by decreasing red cell resistance to oxidative stress [48][49][50]. In developing countries, food is mainly based on cereals such as rice, maize, wheat, oat or sorghum with leguminous, rich in phytic acid, phenolic, and phytate compounds which strongly inhibit the zinc absorption and other minerals [51][52][53]. The mean zinc level was significantly lower in anemic children, while median CRP level was significantly higher in anemic children. ...
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The aim of this study was to explore the relationship of iron and zinc deficiencies and anemia in children aged under 5 years living in malaria endemic area of South Kivu/DRC. We conducted a cross-sectional study in the health zone of Miti Murhesa in South Kivu/DRC. A total of 1088 children in good general health were included in this study. Almost 40% of children were anemic. The prevalence of iron deficiency (ID) was found in 34.9% and 49.1% children based on ferritin or free erythrocyte protoporphyrin (FEP), respectively. If anemia is present, we found iron deficiency anemia (IDA) according to the WHO-criteria (ferritin) in 31%, and according to FEP in 66% of children. The overall prevalence of zinc deficiency was 17.6%. If anemia is present, zinc deficiency was found in 24.4% of children. Inflammation/infection, based upon CRP, was present in 39.7% children. The independent factors associated with anemia were recent illness, middle upper arm circumference, weight-for-height, ID according to FEP, zinc deficiency, and submicroscopic Plasmodium infection. A high prevalence of ID was observed in children in South Kivu according to FEP. Ferritin as acute phase protein was less suited in this population due to a high frequency of infection/inflammation. Iron and zinc deficiencies were found to be significantly associated with anemia in this population.
... Cook et al. [176] reported that, because of the high phytate content of cereal porridges, the iron absorption of native iron and fortification iron might be deficient. Barbro et al. [177] reported that, when the phytate is absent, the zinc and magnesium absorption rate from our food could be increased by 20% and 60%, respectively. ...
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Wheat is an essential constituent of cereal-based diets, and one of the most significant sources of calories. However, modern wheat varieties are low in proteins and minerals. Biofortification is a method for increasing the availability of essential elements in the edible portions of crops through agronomic or genetic and genomic interventions. Wheat biofortification, as a research topic, has become increasingly prevalent. Recent accomplishments in genomic biofortification could potentially be helpful for the development of biofortified wheat grains, as a sustainable solution to the issue of “hidden hunger”. Genomic interventions mainly include quantitative trait loci (QTL) mapping, marker-assisted selection (MAS), and genomic selection (GS). Developments in the identification of QTL and in the understanding of the physiological and molecular bases of the QTLs controlling the biofortification traits in wheat have revealed new horizons for the improvement of modern wheat varieties. Markers linked with the QTLs of desirable traits can be identified through QTL mapping, which can be employed for MAS. Besides MAS, a powerful tool, GS, also has great potential for crop improvement. We have compiled information from QTL mapping studies on wheat, carried out for the identification of the QTLs associated with biofortification traits, and have discussed the present status of MAS and different prospects of GS for wheat biofortification. Accelerated mapping studies, as well as MAS and GS schemes, are expected to improve wheat breeding efficiency further.
... In some minerals, absorption of them, on the other hand, depends on the rate between minerals and phytic acid doses. For example, if the ratio of phytate/zinc is higher than 15-20, it increases the absorption of zinc in the human body (Navert et al. 1985). ...
Chapter
Chemical Contents of Wheat Landraces and Their Contribution to Human Health
... The phytic acid content of bread containing bran was reduced to about 40% after 2 hours of leavening. 74 Fermentation of bread with yeast reduced phytate phosphorus levels. 75 Sourdough fermentation reduced the phytate content of bread by up to 97%. ...
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We summarize how practicing dietitians combined available evidence with clinical experience, to define revised dietary recommendations for phosphorus in chronic kidney disease G3-5D. As well as a review of the evidence base, 4 priority topics were reviewed. These were translated into 3 nutrient level recommendations: the introduction of some plant protein where phosphorus is largely bound by phytate; consideration of protein intake in terms of phosphorus load and the phosphorus to protein ratio; and an increased focus on avoiding phosphate additives. This review summarizes and interprets the available evidence in order to support the development of practical food-based advice for patients with chronic kidney disease.
... It is best to decrease the content of phytic acid in edible parts of staple crops to increase the absorption of minerals to combat mineral malnutrition. Studies have shown that reducing the content of phytate in the diet is strongly related to increased zinc (Barbro et al., 1985) and iron (Hallberg, 1981) absorption. In phytase, wheat transgenic lines show an increment of 4-115% in bioavailable zinc (Abid et al., 2017). ...
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Global food security concerns impact greatly on the United Nation's Sustainable Development Goals, which are heavily focused on eradicating hunger by 2030. The Global Food Security Index of 2019 has reported that 88% of countries claim their is enough food supply in their countries, but it is a dreadful reality that every one in three countries is facing insufficient availability of food supply as per the index, meaning more than 10% of the population is malnourished. Since nutrition is one of the main factors in maintaining a healthy lifestyle and meeting the requirements of food security, several national nutrition surveys conducted in various countries have provided an avenue for governments to assess malnutrition problems across the population. For example, the National Nutrition Survey carried out in 2011 in Pakistan indicated that more than 50% of the population was food insecure based on the nutritional status of available food. This survey also highlighted the acute deficiency of micronutrients in the diet resulting in several disorders, especially among the female population. In view of these facts, efforts are being made globally to enhance the nutritional value of our agricultural products, especially staple crops, by using several biotechnological approaches.
... It is the storage form of phosphorus, an important mineral used in the production of energy as well as the formation of structural elements like cell membranes (Jacela et al., 2010). These foods, are getting a bad reputation due to phytic acid content (Navert, et al,,1985) and its ability to bind to essential minerals such as iron, zinc, calcium, and magnesium in the digestive tract and inhibit their absorption by the body (Weaver &Kannan, 2002). Recent studies indicate despite being somewhat demonized for its ability to reduce mineral absorption, phytic acid actually has some potentially beneficial properties. ...
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Phytic acid is a substance found in many types of plant foods, such as grains, legumes (including peanuts and soybeans), nuts, and seeds. It is the storage form of phosphorus, an important mineral used in the production of energy as well as the formation of structural elements like cell membranes (Jacela et al., 2010). These foods, are getting a bad reputation due to phytic acid content (Navert, et al,,1985) and its ability to bind to essential minerals such as iron, zinc, calcium, and magnesium in the digestive tract and inhibit their absorption by the body (Weaver &Kannan, 2002). Recent studies indicate despite being somewhat demonized for its ability to reduce mineral absorption, phytic acid actually has some potentially beneficial properties. On the plus side, phytic acid can act as antioxidant, exhibits anti-cancer properties, and may have a positive impact on cholesterol and blood sugar (Omni et al., 2004). Preparation methods can reduce the phytic acid content in food, as well as adjusting meal times and food choices (Sade., 2009), can help to have better mineral absorption.
... In some minerals, absorption of them, on the other hand, depends on the rate between minerals and phytic acid doses. For example, if the ratio of phytate/zinc is higher than 15-20, it increases the absorption of zinc in the human body (Navert et al. 1985). ...
Chapter
Wheat plays an important role in human diet and health. Turkey is known as one of the richest countries in terms of wheat varieties. Many wheat varieties from ancient to modern hybrid wheat varieties are still grown in Turkey. The high variety of wheat has enriched the food culture, and it has created a healthy eating habit for this country. It has been proven healthy in terms of its chemical ingredients such as B vitamin types, E vitamin isomers, Zn, and Fe. In addition, they include carotenes and bound form of phenolic acids that are effective in antioxidants. Besides these, wheat bran contains higher amount of fiber, which is important for digestion. Moreover, wheat contains gluten, which is not suitable for celiac patients but should be taken by people who do not have this disease. This chapter provides information about the chemical ingredients and nutritional content of different wheat varieties grown in Turkey.
Chapter
Fibre and some of the associated substances have strong in vitro mineral binding or complexing capacities and hence fibre has been suspected of impairing mineral absorption. The results of mineral absorption studies of fibre-rich diets in humans are, however, not consistent. The specific characteristics of mineral metabolism introduce a number of methodological difficulties that might have contributed to the conflicting results. Furthermore, in several studies either the content of fibre and other interacting substances has not been adequately analysed or the methods used to study absorption and utilisation have not been sensitive enough to reveal any effects.
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Chapter
The major biochemical function of zinc is as a constituent of metalloenzymes. The first described was carbonic anhydrase in 1940, and since then more than 200 different zinc enzymes have been identified in plant and animal tissue. Alcohol dehydrogenase, superoxide dismutase, DNA-polymerase, RNA-polymerase, alkaline phosphatase and carboxypeptidase are all zinc-metalloenzymes and examples can be found in each of the six major categories of enzymes. This means that zinc is involved in more or less every biochemical process in the body. In some of these enzymes zinc is present at the active site e.g., acting as an electron acceptor, in others and in non-enzyme proteins the function of zinc is structural as S—S bridges or cross-links between thiolates and imidazoles.
Chapter
The absorption of zinc can be assumed to be determined to a large extent by the chemical environment at its site of absorption. Thus, absorptive efficiency will be influenced by the solubility of the zinc compounds present, by the presence of ligands of low molecular weight and by the competition between zinc and other minerals for carriers or uptake sites. To understand the mechanisms of zinc absorption, it is important to identify the factors promoting or inhibiting zinc uptake. Such knowledge can be used to improve zinc absorption from diets low in zinc and to develop special diets such as infant and enteral formulas intended for use at times when sensitivity to a suboptimal zinc supply may be increased. Efforts to eliminate strong antagonists of zinc absorption during food preparation and processing can also be made once these factors have been identified.
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Rice bran (RB) could be used for animal feed or human food because of its protein and minerals profile, provided that the rice bran oil and the excessive fibre contents could be eliminated or reduced. In this work, the granulometric and the proximal characteristic of RB and deffated RB (DRB) were studied. It was found that RB shows a predominance of coarse fractions (>70% of the mass corresponds to mesh sizes >120), whereas DRB exhibits a more uniform granulometric profile. The fat content of the DRB was <10g·kg -1. The fine fractions of both RB and DRB had a larger percentage of free nitrogen extract (ca. 600g·kg-1), while the coarse fractions were rich in neutral detergent fibre (NDF, ca. 420g·kg -1). In the particular case of DRB, up to 36% of the mass fell within the fine fraction range (<0.092mm, mesh 180) and was low in NDF (180g·kg-1) and high in protein (126.6g·kg -1). This flour deserves further studies regarding its potential for human food or animal feed applications.
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Zinc intake of adults in Germany was determined from 1988 to 1996 by the duplicate portion method. Altogether, 14 test populations each consisting of at least 7 women and 7 men collected their daily consumed food and beverages over 7 subsequent days. Furthermore, 10 female and 10 male vegetarians took part in a duplicate study in 1996. Our results show that food dry matter consumption of persons with mixed diets did not change from 1988 to 1996. Vegetarians (women: 390 g/day, men: 479 g/day) consumed 32% more dry matter than non-vegetarians. However, energy intake was not influenced by kind of diet. Zinc intake of adults with mixed diets decreased from 1988 to 1996 statistically saved by 20 to 25%. In 1996, women took in 6.0 mg Zn/day and men 7.5 mg Zn/day. The zinc intake of men amounted to about 25% more than that of women. This sex-depending difference vanished when zinc consumption was related to body weight. Possible reasons for the declining zinc supply might be changes in food preference, a higher consumption of processed foodstuffs, for example refined sugar, polished rice and flour with low extraction rate, and a decreased intake of meat. Compared to this, zinc intake of vegetarians (women: 8.6 mg Zn/day, men: 9.5 mg Zn/day) was 34% higher than that of non-vegetarians. These findings were caused by the enhanced dry matter intake of vegetarian persons. It seemed that the higher zinc consumption of vegetarians might compensate the lower bioavailability of zinc due to phytate-richer diet. Both non-vegetarian and vegetarian test persons were healthy and showed no visible signs of zinc deficiency. Mild zinc deficiency could not be excluded, especially for persons consuming less than 5 mg Zn/day. In conclusion, zinc intake of adults in Germany is marginal and should be improved.
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Maize is a staple human food eaten by more than a billion people around the world in a variety of whole and processed products. Different processing methods result in changes to the nutritional profile of maize products, which can greatly affect the micronutrient intake of populations dependent on this crop for a large proportion of their caloric needs. This review summarizes the effects of different processing methods on the resulting micronutrient and phytochemical contents of maize. The majority of B vitamins are lost during storage and milling; further loss occurs with soaking and cooking, but fermentation and nixtamalization (soaking in alkaline solution) can increase bioavailability of riboflavin and niacin. Carotenoids, found mainly in the kernel endosperm, increase in concentration after degermination, while other vitamins and minerals, found mainly in the germ, are reduced. Mineral bioavailability can be improved by processing methods that reduce phytic acid, such as soaking, fermenting, cooking, and nixtamalization. Losses of micronutrients during processing can be mitigated by changes in methods of processing, in addition to encouraging consumption of whole-grain maize products over degermed, refined products. In some cases, such as niacin, processing is actually necessary for nutrient bioavailability. Due to the high variability in the baseline nutrient contents among maize varieties, combined with additional variability in processing effects, the most accurate data on nutrient content will be obtained through analysis of specific maize products and consideration of in vivo bioavailability.
Conference Paper
Deficiencies of iron and zinc are common worldwide. Various strategies have been used to combat these deficiencies including supplementation, food fortification and modification of food preparation and processing methods. A new possible strategy is to use biotechnology to improve trace element nutrition. Genetic engineering can be used in several ways; the most obvious is to increase the trace element content of staple foods such as cereals and legumes. This may be achieved by introduction of genes that code for trace element-binding proteins, overexpression of storage proteins already present and/or increased expression of proteins that are responsible for trace element uptake into plants. However, even very high levels of expression may not substantially increase the iron and zinc contents unless many atoms of trace elements are bound per protein molecule. Another possibility is to introduce a protein that specifically enhances trace element absorption even in the presence of naturally occurring inhibitors, thus improving bioavailability. Genetically modifying plants so that their contents of inhibitors of trace element absorption such as phytate are substantially reduced is another approach. Increasing the expression of compounds that enhance trace element absorption such as ascorbic acid is also a possibility, although this has received limited attention so far. Iron absorption may be increased by higher ascorbic or citric acid content but require overexpression of enzymes that are involved in the synthetic pathways. Finally, a combination of all of these approaches perhaps complemented with conventional breeding techniques may prove successful.
Conference Paper
The main barriers to successful iron fortification are the following: 1) finding an iron compound that is adequately absorbed but causes no sensory changes to the food vehicle; and 2) overcoming the inhibitory effect on iron absorption of dietary components such as phytic acid, phenolic compounds and calcium. These barriers have been successfully overcome with some food vehicles but not with others. Iron-fortified fish sauce, soy sauce, curry powder, sugar, dried milk, infant formula and cereal based complementary foods have been demonstrated to improve iron status in targeted populations. The reasons for this success include the use of soluble iron such as ferrous sulfate, the addition of ascorbic acid as an absorption enhancer or the use of NaFeEDTA to overcome the negative effect of phytic acid. In contrast, at the present time, it is not possible to guarantee a similar successful fortification of cereal flours or salt. There is considerable doubt that the elemental iron powders currently used to fortify cereal flours are adequately absorbed, and there is an urgent need to investigate their potential for improving iron status. Better absorbed alternative compounds for cereal fortification include encapsulated ferrous sulfate and NaFeEDTA, which, unlike ferrous sulfate, do not provoke fat oxidation of cereals during storage. Encapsulated compounds also offer a possibility to fortify low grade salt without causing off-colors or iodine loss. Finally, a new and useful additional approach to ensuring adequate iron absorption from cereal based complementary foods is the complete degradation of phytic acid with added phytases or by activating native cereal phytases.
Chapter
Proteins of plant origin offer considerable promise for alleviating the shortage of food protein now facing many segments of the world’s population—a situation which will certainly become more acute if the global expansion of the population continues unabated. It should be recognized, however, that many plants commonly consumed by man contain substances which may have an adverse effect on the nutritional properties of the protein unless inactivated or eliminated by suitable methods of processing or household preparation.1,2In many cases these substances are relatively innocuous in their native form but may be converted to a toxic state when acted upon by enzymes which frequently accompany these substances in the tissues of the same plant. Paradoxically, advantage can sometimes be taken of the action of these endogenous enzymes to effect the removal of these toxicants by appropriate methods of processing. Alternatively, exogenous enzymes may be used for detoxification, such as fermentation by molds or bacteria or the use of enzyme preparations derived from these microorganisms. In this chapter examples will be provided which illustrate the manner in which enzymes have been used, either endogenously or exogenously, to detoxify various sources of foods so that they can be used in the diet of man or animals
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The binding of copper, cadmium and zinc ions to some soluble and gelforming types of dietary fibre (guar gum, low and high methoxylated pectin and sterculia gum) has been investigated potentiometrically. Considerable binding was found to low methoxylated pectin, but the binding to sterculia gum and high methoxylated pectin was less pronounced. The binding to guar gum was negligible. Thus, the formation of complexes seemed to be due to the proportion of free carboxyl groups. The amount of added metal bound to sterculia gum was proportional to the fibre concentration, whereas the pectins showed increased binding at higher fibre concentrations. This was possibly due to intermolecular interactions between the polymers and metal ions. The order of complex formation ability to the fibres investigated was different for different metals. To low methoxylated pectin the order Cu > Zn >> Cd was observed.
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1. The effect of extrusion cooking of a high-fibre cereal product on digestibility of starch, fibre components and phytate in the stomach and small intestine was studied by in vivo digestion in ileostomy subjects, as well as its effect on ileostomy losses of fat, nitrogen, sodium and potassium. 2. Seven ileostomy subjects were studied during two periods (each of 4 d) while on a constant low-fibre diet supplemented with 54 g/d of a bran-gluten-starch mixture (period A) or the corresponding extruded product (period B). 3. Extrusion cooking, using mild conditions, did not change the content of starch, dietary fibre components or phytate of the bran product, but the phytase (EC 3.1.3.26) activity was lost. During the period using the extruded bran product, there was a significant increase in recovery of phytate-phosphorus (period A, 44% of intake; period B, 73% of intake). The amount of fibre components, fat, fatty acids, N, Na, K, water and the ash weight of the ileostomy contents did not differ between the two periods. Only 0.6 and 0.7% respectively of ingested starch was recovered in ileostomy contents in periods A and B, while the fibre components were almost completely recovered. 4. Extrusion cooking, using even mild conditions, may lead to a considerable impairment in the digestion of phytate, probably due to a qualitative change in phytate and a loss of phytase activity. Starch, before and after extrusion cooking, is almost completely digested in the stomach and small intestine while fibre components are digested to a very small extent.
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yeast and fermentation time was investigated to determine phytic acid content, organoleptic properties and texture of traditional bread, Lavash, at Kermanshah province. Lavash bread with different flour and sourdough was produced after 0, 2, and 4 hours of fermentation. Results analysis showed both of fermentation type and fermentation time had significant effect on phytic acid content and organoleptic properties. Mean comparison showed Beiglari flour (with 17.5 % bran) fermented with bakeryʹs yeast during 4 hours had the least phytic acid. The result of organoleptic properties by Duncan test showed fermented Atlas flour (with 14.5 % bran) during 2 hours with bakery’s yeast had the best organoleptic characteristics. Correlation of response showed that phytic acid content had negative relationship with overall acceptance of sensory properties (p<0.01). The results of SEM analysis showed Atlas flour with 2 hours fermentation that had the best organoleptic characteristics had higher porosity and better texture than Beiglari flour with 4 hours fermentation.
Article
The aim of this study was to determine the bioavailability of zinc in rats fed with zinc-enriched soybeans that were cultivated using a foliar spray containing zinc. Male Sprague Dawley rats were fed a basal diet (control), a zinc-deficient diet, or one of three test diets containing ordinary soybeans, zinc-enriched soybeans, and soybeans with zinc gluconate for 3 weeks. Body weight was significantly higher (p<0.05) in rats fed zinc-enriched soybeans than in the control, ordinary soybean, and zinc-deficient diet groups. Apparent zinc absorption was also significantly higher (p<0.05) in the zinc-enriched soybean group than in the control group (81.83±3.93 vs. 59.17±6.67%). Plasma superoxide dismutase and alkaline phosphatase activity in the zinc-enriched soybean group were significantly higher (p<0.05) than in the zinc-deficient diet group. Moreover, bone strength was higher in the zinc-enriched soybean group compared with the zinc-deficient diet group (51.28±2.37 vs. 31.55±2.35N). These results suggest that the zinc in the zinc-enriched soybeans suppressed the inhibitory effect of phytic acid on zinc metabolism in rats.
Article
The range of food items from which diets are constituted and the preparative procedures used in their processing can influence both the total intake of zinc and its biological availability. That such variables can give rise to an inadequate zinc supply is exemplified by the observations of zinc-responsive growth failure in American children with a zinc intake of 5, mg/d (Krebs et al. 1984) and also in Iranian adolescents (Halsted et al. 1972) on diets providing 19–22 mg of zinc daily (Maleki 1973). Sensitive indices of zinc status, suitable for evaluation of availability and adequacy of the zinc supplied by the differing diets of individuals or populations, are still lacking. Present data indicate, however, that dietary attributes influencing the efficiency with which zinc can be absorbed are the main determinants of zinc availability. Thus, experimental studies of zinc absorption from composite meals or diets can provide useful information on the relative values of various food combinations as zinc sources.
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1. Studies were carried out in vitro to examine the effects of phytate on the solubility of the trace elements zinc, copper and manganese. Appropriate volumes of a solution of sodium phytate were added to a mineral solution to achieve phytate: Zn values of from 0: 1 to 45:1. In a second series the same values for phytate: Zn were achieved by varying the amount of added Zn at a fixed phytate concentration. 2. In both experiments > 85% of the Zn was rendered insoluble at pH 6.5 even at the lowest value for phytate:Zn (5:1). The effect of phytate on Zn solubility was greater than effects on Cu or Mn. 3. In a dietary study, rats were offered a semi-synthetic egg-albumin-based diet with added phytate. Two series of diets were prepared, the first had a constant Zn content (18.5 mg Zn/kg) and the amount of sodium phytate varied so as to achieve values for phytate: Zn of from 0:1 to 40:1 (series 1). In the second series, the same values for phytate:Zn were achieved by adding a fixed amount of phytate (7.4 g phytic acid/kg) while the amount of Zn was varied (series 2). 4. Dietary phytate caused significant reductions in growth rates, plasma Zn concentrations and hair Zn concentrations and greying of the coat at values for phytate:Zn of 15:1, 10:1, 10:1 and 15:1, respectively. 5. While phytate was apparently slightly more effective in reducing Zn status when phytate:Zn values were achieved at the lower absolute levels of phytate and Zn (series I diets), the differences at equivalent phytate:Zn values were small. It was concluded that phytate:Zn values can be used as an indicator of Zn availability from phytate-rich diets. Rats offered three diets containing soya-bean-based textured-vegetable-protein (TVP) exhibited low rates of weight gain compared with rats offered an egg-albumen-based diet of similar Zn content (14.5 mg Zn/kg). Additional Zn supplied in drinking-water (25 mg Zn/l) was without effect on rats consuming the egg-albumin diet but significantly improved the weight gain of rats on the TVP diets. 7. It was concluded that phytate naturally present in TVP behaves similarly to phytate added to an otherwise phytate-free diet and that the reduced availability of Zn in TVP diets can be accounted for entirely by their phytate contents.
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1. Studies on mineral absorption were carried out in ileostomy patients using the metabolic balance technique. The effect of wheat bran on the absorption of phosphorus, calcium, magnesium, zinc and iron was studied. The extent of digestion of bran phytate in the stomach and small intestine was also investigated. 2. Eight patients with well established conventional ileostomies were studied during two periods while on a constant low-fibre diet. In the second period, 16 g wheat bran/d (American Association of Cereal Chemists) was added to the diet. The amount of phytate-P, non-phytate-P, Ca, Mg, Zn and Fe was determined in the ileostomy contents and in duplicate portions of the diet. 3. Of the added bran phytate-P 24–61% was recovered in the ileostomy contents. In the bran period a significantly decreased amount of Zn was absorbed, while the apparent absorption of Fe and phytate-P increased and that of non-phytate-P, Ca and Mg remained constant. Due to the mineral content of bran, the relative absorption differed in some respects from the absolute absorption, being decreased for Zn, Mg and phytate-P but unchanged for Ca, Fe and non-phytate-P. 4. It is concluded that phytate is partly digested in the stomach and small intestine or possibly absorbed. Addition of 16 g bran/d to the diet does not seem to impair the mineral absorption from the small intestine except that of Zn.
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1. The effect of heat treatment of bran on true zinc absorption was measured using an isotope-dilution technique. A bran-based breakfast cereal (heated to 204° for 40 min during manufacture) was incorporated into a semi-synthetic diet at a level of 180 g/kg, A parallel diet was formulated containing an identical weight of untreated bran from the same source plus other ingredients used to make the cereal. 2. Young male Wistar rats (mean weight 80 g) were injected intramuscularly with ⁶⁵ Zn to label body Zn. They were given the heat-treated- and untreated-bran diets for 9 d. During the last 6 d of this period Zn intakes and faecal and urinary Zn were measured in order to calculate apparent Zn retention. True Zn retention was measured by taking into account losses of Zn of endogenous origin (labelled with ⁶⁵ Zn), by measuring faecal and urinary ⁶⁵ Zn taking the mean specific radioactivity of Zn in kidneys and upper small intestine to represent specific radioactivity of endogenous origin. 3. Heat treatment of bran removed approximately one-third of the phytate, but this was not enough to improve Zn absorption from the diet. True Zn retention measured by isotope dilution was significantly higher ( P < 0.02) than apparent Zn retention measured bv the conventional balance technique. 4. The hypothesis that a reduction in particle size of bran would improve mineral availability was tested by feeding coarse and milled bran (100 g/kg diet) in a semi-synthetic diet to rats and measuring true Fe and apparent Zn absorptions. The importance of phytate was also investigated by feedino a diet containing dephytinized bran. 5. Male Wistar rats (mean weight 172 g) were given diets containing coarse, milled or dephytinized bran for 9 d. Fe and Zn intakes were measured and faeces and urine collected for Fe and Zn analysis. 6. The mean (±SE) particle size of the bran was reduced on milling from 3.5 (± 1.8) to 0.2–0.5 mm. There were no differences in the fraction of Fe retained between the three groups. Particle size had a small effect on Zn retention which was marginally higher in rats on the milled-bran diet (0.126 (± 0.023)) than in those on the coarse-bran diet (0.087 (± 0.012)). Total removal of phytate had a greater effect and apparent Zn retention from the dephytinized-bran diet was significantly higher (0.182 (±0.027), P < 0.01).
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1. The capacity of wheat bran to impair mineral absorption independent of its phytate content was studied by metabolic balance studies in man. 2. Three breads were prepared, equivalent to white, brown and wholemeal, by adding bran in different quantities to white flour. Calcium, iron, zinc and sodium phytate were added to the loaves to make the amounts equal in all breads. 3. Six healthy volunteers were studied for three consecutive 24-d-periods during which they ate a controlled diet, typical of that normally consumed in the UK but with 200 g bread/d. Only the type of bread changed between each dietary period. 4. The phytate contents (mmol) of 200 g of each of the breads after baking were: white 2·3, brown 2·1 and wholemeal 2·2; non-starch polysaccharide contents (9) were: white 3·3, brown 10·9 and wholemeal 18·7 5 . The increased amount of bran in the breads increased stool output in the expected way but no change was seen in Ca, Zn and Fe balance. Blood levels of these minerals remained unchanged. 6. It is concluded that wheat bran and, in particular, the cell-wall polysaccharides of bran, are unlikely to exert a significant effect on mineral absorption in man, in amounts customarily eaten, independently of the effect of phytate present in the bran.
Article
Because of the dietary components that affect availability, it is not possible to define a zinc requirement for all dietary regimens. The source of zinc must be taken into consideration. In general, the zinc in animal products is more readily absorbed than that in plant products, particularly those that arise from plant seeds. Phytate, an ion peculiar to plants, binds zinc and decreases its availability. In the presence of phytate, excess calcium aggravates zinc binding. Chelating agents, whether man-made or those that occur naturally in foods, may compete with phytate to increase availability.
Article
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.
Article
The studies of Reinhold and his co-workers (Reinhold, 1975) suggest that the high incidence of mineral-deficiency diseases (notably zinc deficiency) in the rural population of Iran is due to the high intake of dietary fibre. Experiments by the author conflict with this view and show that, when a fibre-rich and phytaterich cereal product is fed to rats, phytate is the major determinant of zinc availability. The mechanisms by which dietary fibre could impair mineral absorption are discussed in relation to fibre source, amounts consumed and the possible modifying effects of other dietary ingredients.
Article
Wheat breads and their major components take up from aqueous solutions and firmly bind zinc, iron and calcium at pH 6.0 to 7.5. Binding of the metals to starch, bread, or flour is diminished by the action of pancreatin. A portion of the calcium and zinc are released from bran by the action of phytase. However, totally dephytinized wholemeal bread and bran show an enhanced ability to bind metal. This and other evidence indicates that fibre largely determines the availability of bivalent metals of bread for absorption by the intestine.
Article
Metabolic balances of zinc, calcium, phosphorus and nigrogen were measured in 13 villagers resident in the Shiraz region of Iran for the purpose of surveying the state of mineral nutrition of a population that subsists on diets containing large amounts of phytate. Strikingly high retentions of zinc, calcium and phosphorus occurred during the latter six days of nine day periods during which a nutritious diet containing an abundance of these elements in available form was fed. Nitrogen, by contrast, was not retained. The results support the belief that severe depletion of mineral elements exists in the villagers studied. This is attributed to the action of phytate in decreasing the availability of these elements. Destruction of phytate in the gut apparently is not sufficient to overcome the effects of the high phytate intakes.
Article
The relation of phytate concentration to colour produced by standard quantities of thiocyanate and ferric iron in a solution is inverse and almost linear. This is the basis of the method proposed for the determination of phytate phosphorus. It has been applied to the determination of quantities between 75 and 150 ug. in extracts from dried peas with an accuracy of ± 5%. Chloride, sulphate, citrate, tartrate and malate do not interfere in concentrations of the same order as that of the phytate. Interference by o-I mg. of orthophosphate phosphorus is negligible; 0.4 mg. causes a positive error of less than 5%. It is suggested that there may be less interference in aqueous alcohol.
Article
Adding 36 g of wheat fiber for 3 weeks to the metabolically controlled diets of six subjects produced a significant increase in daily fecal weight from 70.8 g +/- 6.2 SEM to 217 g +/- 12.1; serum iron also fell by 21 micrograms/100 ml +/- 2.1 SEM (P less than 0.001) during the added fiber period (measured in five subjects) as did mean corpuscular volume and mean corpuscular hemoglobin. Fecal neutral steroid concentration (measured in four subjects) fell from 31 to 17.3 mg/g dry weight (P less than 0.05) but the change in neutral steroid output and in acid steroid concentration and output was not significant. No change was seen in the serum levels of cholesterol and triglyceride.
Article
1. A study has been made of the zinc, copper, iron, manganese, protein (nitrogen x 625) and phytic acid contents of nineteen soya-bean-based textured-vegetable-protein (TVP) meat-extenders and meat-substitutes and of three ‘ready-prepared’ canned meals containing TVP. 2. Phytate analysis was performed using a newly-developed method based on Holt's (1955)procedure. This method enabled the phytate content of milligram quantities of TVP to be estimated, with an SD for six replicates of 3%. 3. The Fe, Cu and Mn contents (mg/kg) of the meat-extenders or meat-substitutes varied, wzith values of 59.4–144, 14.1–19.7 and 19.5–29.1 respectively. The protein content of these products was approximately 500 g/kg. 4. The phytate content of the meat-extenders and meat-substitutes ranged from 11.0to 20.2 g/kg and the Zn content from 35.0 to 49.4 mg Zn/kg. The calculated molar ratio, phytate:Zn varied from 25 to 42. 5. The trace element, phytate and protein contents of the ‘ready-prepared’ canned meals were 30–50 %: lower than the meat-extenders and meat-substitutes. 6. Cooking the ‘ready-prepared’ meals as specified by the manufacturers was without effect on the trace element or phytate content. 7. When TVP was fed to rats as the only protein source, they had significantly lower growth rates and plasma Zn concentrations than rats given an egg-albumen-based diet of similar Zn content (14.5mg Zn/kg). Supplementation of the TVP diet with Zn (100 mg Zn/kg) significantly increased growth rate and plasma Zn concentration whereas Zn supplementation of the albumen diet was without effect. 8. The possible implications of consumption of TVP products in relation to Zn status of the human population is discussed.
Article
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.
Article
Three young men were given approximately 2·5 g. of phytic acid daily, first as purified sodium phytate together with leavened flat wheat bread for 28 days, then for 32 days as tanok, the phytate-rich unleavened wholemeal flat wheat bread that is the staple food of many Iranian villagers. Purified phytate administration was accompanied by increased losses of zinc in fæces which varied in degree when compared with outputs during a control period which preceded the high phytake intakes. Calcium balances became negative in one, significantly less positive in one, and were unchanged in one of the subjects. Phytate in the form of tanok led to negative zinc balances and strongly negative calcium balances in all. Urinary phosphate excretion decreased while tanok was the source of phytate, a change attributed to decreased phytate destruction in the gut probably due to an inhibitor present in the bread. Negative calcium balances persisted after 60 days of phytate consumption, and the claim that the effects of phytate are ameliorated after a few weeks with return to positive calcium balances was not confirmed. Plasma-zinc and serum-iron concentrations fell shortly after phytate consumption began, but later rose while phytate ingestion continued. However, plasma-calcium and serum-phosphorus fell and remained below normal. The results suggest that high-phytate intakes can cause the disturbances of zinc and calcium metabolism prevalent among Iranian villagers. They are applicable also to other populations who eat a lot of unleavened wholemeal bread.
Article
There was a significant lowering of serum-triglycerides and plasma-calcium in fourteen subjects fed unprocessed wheat bran (median dose 38 g. per day) for 4-9 weeks (median 5 weeks).
Article
The availability of zinc in leavened and unleavened wholemeal wheaten breads was examined. Wheat, labeled with "Zn by injection of label into stems shortly before maturation, was converted into wholemeals of high extraction rate. These were used to prepare yeast-leavened and also unleavened flat breads, the latter being similar to those consumed as the principal dietary staple in rural Iran and nearby countries. The solubility of °°Zn and of stable Zn was two- to threefold greater when leavened bread was suspended in 0.85% NaCl solutions adjusted to pH values between 4.5 and 7.5 than when unleavened bread was so suspended. Uptake of ""Zn by strips of rat jejunum and ileum from suspensions of leavened bread also was significantly greater. The solubility of ""Zn in suspensions of wholemeal bread, either leavened or unleavened, increased exponentially as pH decreased from 7.0 to 4.5. A plot of solubility of ""Zn against pH yielded a relationship closely resembling that described by Kaufman and Kleinberg for titration of phytic acid with calcium hydroxide over this pH range, a finding that was attributed to the interaction of zinc with calcium phytate. It is con cluded that fermentation with yeast markedly increases the physiological availability of zinc in wholemeal bread. The gains are attributed in part to the action of yeast in destroying phytate. However, the gain in solubility exceeded by severalfold that to be expected if destruction of phytate was the only cause, so that other changes brought about by fermentation also must contribute. J. Nutr. 104: 976-982, 1974.
Article
The total intake of energy and nutrients was recorded during 5 consecutive d in ten constipated patients in a geriatric ward. Twenty grams of ordinary or low-phytate wheat bran was then added to their diet and the 5-d food intake was recorded after 6 and 12 weeks, respectively. The intake was generally satisfactory and decreased in only two women on bran treatment. The hospital diet had a high mineral content and calcium, magnesium, zinc and iron levels in serum did not decrease when wheat bran was added to the diet. Consequently no difference was found in serum mineral levels, when ordinary wheat bran was replaced by a low-phytate bran.
Article
Zinc absorption from 450 mL of human milk, cow's milk, humanized cow's milk formula, cereal-cow's milk formula, and soy formula was determined in healthy adults. The milks and formulas were extrinsically labeled with zinc chloride Zn 65 and the absorption was determined from measurement of the whole-body retention of the isotope. The zinc content of the formulas was comparable to or higher than that of human milk. Absorption of zinc was 41% +/- 9% from human milk and 28% +/- 15% from cow's milk. Absorption was 31% +/- 7% from the humanized cow's milk formula, 22% +/- 11% from the cereal-cow's milk formula, and 14% +/- 4% from the soy formula. These results indicate that, with the present levels of zinc supplementation, the amount of zinc absorbed from infant formulas is considerably lower than that absorbed from human milk.
Article
The absorption of zinc in man from composite meals of conventional foods with various main protein sources was measured with a radionuclide technique. The meals were extrinsically labeled with 65Zn and the absorption of zinc was determined from a measurement of the whole-body retention of the isotope about 2 weeks after ingestion of the labeled meal. The meals consisted of a meat patty made from either chicken, beef, or soybeans, and included potatoes, tomatoes, and white bread. For meals based on animal protein a positive correlation was found between zinc absorption and zinc content. When 25% of the animal protein in the chicken meal was replaced by defatted soy flour neither the zinc content nor zinc absorption were significantly influenced. The same substitution in a beef meal resulted in a decrease in zinc content and also a lower zinc absorption. The absorption from a soybean meal did not differ from an animal protein meal with the same zinc content. Lower zinc absorption was found when the calcium content of a soybean meal was increased by the addition of milk. For this study, the total zinc content of the meal was the most important factor influencing the amount of zinc absorbed.
Article
A low molecular weight zinc binding compound from human milk has been purified by ultrafiltration, gel filtration, and ion-exchange chromatography. Evidence is provided that this compound is citrate. A higher amount of citrate-bound zinc was found in human milk than in cow's milk. It is suggested that the therapeutic value of human milk for patients with the genetic disorder of zinc metabolism acrodermatitis enteropathica (AE) derives from a greater content of bioavailable zinc citrate in human than in cow's milk.
Article
The effect of phytate to zinc (Zn) molar ratio on zinc bioavailability was evaluated in rats. The bioavailability was determined by giving an oral dose of 65Zn and measuring the liver uptake and disappearance from the gastrointestinal tract after 4 hours and fecal and urinary 65Zn excretion from 24 to 168 hours. Rats were fed a diet containing 12 ppm zinc from zinc sulfate with and without phytic acid from sodium phytate for 14 days. At the end of 14 days feeding, the rats were intubated with a homogenized diet containing 12 ppm zinc, one microCi 65Zn and graded levels of phytic acid so that the phytate:Zn molar ratio varied from 0 to 100. Zinc bioavailability was significantly reduced only in the rats fed diets containing phytate and intubated diet containing phytate:zinc molar ratio of 12.5 and above. The results from this study also indicated that measuring 65Zn disappearance and uptake was a valid bioassay for determining zinc bioavailability. The effect of isolated soybean protein on extrinsic zinc bioavailability was also evaluated in rats fed zinc adequate and zinc deficient diets. The results showed that zinc bioavailability was significantly reduced by replacing egg white protein with isolated soybean protein only when the rats were fed zinc deficient diet prior to single oral dose of 65Zn mixed with test proteins. The effect of isolated soybean protein on intrinsic zinc bioavailability for the growing rats was also evaluated. The results demonstrated that the zinc bioavailability in isolated soybean protein can be improved by fortifying with zinc so that the phytate:Zn molar ratio is less than 10.
Article
The phytate content of several foods is presented. Published zinc values were used to calculate phytate:zinc molar ratios. These ratios can be used to estimate the relative risk of having an inadequate intake of zinc. They may be used in planning menus to select the combination of foods that will supply the most available zinc to the daily diet. On the basis of animal experiments to date, a daily phytate:zinc molar ratio of 10 or less is thought to be acceptable in providing adequate dietary zinc, and daily ratios consistently above 20 may jeopardize zinc status. Many factors other than the daily dietary phytate:zinc molar ratio influence zinc nutriture, but the ratio concept is a tool which may contribute to a more accurate assessment of zinc status.
Article
The absorption of zinc in man from composite meals based on bread was measured with a radionuclide technique using 65Zn and whole-body counting. Bread was made up from wheat flour of 100 and 72% extraction rate. A lower absolute amount of zinc was absorbed from the white bread compared to the absorption from the same amount of wholemeal bread. When the two types of bread were enriched with zinc chloride the absorption was higher from the white bread than from the wholemeal bread. Addition of calcium in the form of milk products improved the absorption of zinc from a meal with wholemeal bread. A significant positive correlation was found between zinc absorption and the protein content in meals containing milk, cheese, beef, and egg in various combinations with the wholemeal bread.
Article
In rats fed semipurified diets, bioavailability of dietary zinc was tested at different phytate/zinc molar ratios; growth and zinc in femurs were the criteria of adequacy. On diets with 10--12 ppm zinc, the growth of rats was not affected by phytate/zinc molar ratios of 12 or less if the level of dietary calcium was 0.75% but was depressed at ratios greater than 6 if the level of calcium was 1.75%. Phytate/zinc molar ratios greater than these did not depress growth if the dietary zinc concentration was at least 2.5 and 5 times the minimal requirement for growth at dietary calcium levels of 0.75 and 1.75%, respectively. At the maximum phytate/zinc molar ratio that did not depress growth, accumulation of zinc in femurs was depressed. Small increases in dietary calcium (from 0.75 to 0.87%) depressed growth of rats fed diets with 12 ppm zinc and a phytate/zinc molar ratio of 25. Preformed Zn3 and Zn6 phytate preparations were equivalent to ZnSO4.7H2O as dietary zinc sources. The data indicated that high dietary calcium per se reduced zinc bioavailability. The maximum phytate/zinc molar ratio that did not depress growth of young rats was greatly influenced by dietary calcium level and somewhat influenced by total dietary zinc concentration.
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