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Feeding of sorghum with a high level of tannin (high-tannin sorghum) to rats caused changes in gene expression in parotid glands similar to isoproterenol treatment. Within 3 days the parotid glands were enlarged about 3-fold and a series of proline-rich proteins were increased about 12-fold. Unlike isoproterenol treatment, no changes were observed in the submandibular glands, and a Mr 220,000 glycoprotein in parotid glands was not induced. Amino acid analyses, electrophoretic patterns, and cell-free translations of mRNAs all confirmed that the proline-rich proteins induced by feeding high-tannin sorghum were identical to those induced by isoproterenol treatment. Binding curves for proline-rich proteins to tannins showed affinities 10-fold greater than bovine serum albumin and tannins.A series of unusual proteins containing 25-45% proline have been isolated from human and rat salivary glands and the secretions of salivary glands (1-6). Two families of either acidic or basic proline-rich proteins (PRPs) are commonly found, with variations in glycosylation and phosphorylation. The phosphorylated PRPs are postulated to be involved in dental repair (7) because these substances have a very high affinity for hydroxyapatite. The functions of the basic PRPs, which have isoelectric points of >10 (8), are unknown.The condensed tannins (proanthocyanidins, oligomers of flavan-3-ols) present in many plant tissues characteristically bind and precipitate proteins (9). This astringency of the tannins, which are rich in phenolic groups, apparently protects the plant tissue against ingestion by some insects (10) and seed-eating birds (11). Seeds of bird-resistant cultivars of sorghum, a major cereal of the semi-arid tropics, contain a high level of tannin (high-tannin sorghum), which diminishes the nutritional value of the grain by inhibiting protein digestion (12) and possibly by other mechanisms. In studies designed to define the interaction of tannins and proteins, Hagerman and Butler (13) were able to demonstrate that tannins have an unusually high affinity for proteins rich in proline. Because the gastrointestinal tractspecifically the oral cavity-is a source of PRPs, Hagerman and Butler (13) proposed that salivary PRPs could possibly interact with tannins and serve to protect dietary proteins and digestive enzymes.In this study we report on the dramatic effects on rat parotid glands of feeding high-tannin sorghum. High-tannin sorghum ingestion mimics some of the phenotypic changes observed after treatment of rats with the a-agonist isoproterenol (6,8 Feeding Trials. Sprague-Dawley male rats (70 g) (Murphy Breeding Laboratories, Plainfield, IN) were maintained on Purina Lab Chow for 3-6 days before initiating the feeding trials. Sorghum grains were ground and incorporated into diets of the following composition (% of diet): sorghum, 92.6; corn oil, 2.0; minerals (AIN-76), 3.5; vitamins (AIN-76), 1.0; lysine HCI, 0.75; choline chloride, 0.14; and butylated hydroxytoluene, 0.01. Feed and water were provided ad lib. I...

This study aimed to determine the effect of a multiple-micronutrient-fortified beverage on the micronutrient status, physical fitness, and cognitive performance of schoolchildren. The study was a randomized, double-blind, placebo-controlled trial of schoolchildren assigned to receive either the fortified or nonfortified beverage with or without anthelmintic therapy. Data on hemoglobin level, urinary iodine excretion (UIE) level, physical fitness, and cognitive performance were collected at baseline and at 16 weeks post-intervention. The fortified beverage significantly improved iron status among the subjects that had hemoglobin levels < 11 g/dl at baseline. The proportion of children who remained moderately to severely anemic was significantly lower among those given the fortified beverage. In the groups that received the fortified product, the median UIE level increased, whereas among those who received the placebo beverage, the median UIE level was reduced significantly. Iron- and/or iodine-deficient subjects who received the fortified beverage showed significant improvements in fitness (post-exercise reduction of heart rate) and cognitive performance (nonverbal mental ability score). The study showed that consumption of a multiple-micronutrient-fortified beverage for 16 weeks had significant effects on iron status, iodine status, physical fitness, and cognitive performance among iron- and/or iodine-deficient Filipino schoolchildren. Anthelmintic therapy improved iron status of anemic children and iodine status of the iron-adequate children at baseline but it had no effect on physical fitness and cognitive performance. The results from the clinical study showed that a multiple-micronutrient-fortified beverage could play an important role in preventing and controlling micronutrient deficiencies.

Iron deficiency affects over two billion people worldwide (Lotfi, M.; Venkatesh Mannar, M. G.; Merx, R. J.; Naber-van den Heuvel, P. Micronutrient Fortification of Foods: Current Practices, Research,and Opportunities; Micronutrient Initiative: Ottawa, Ontario, Canada, 1996). However, fortifying foods with highly bioavailable iron is technically challenging because of off-color and off-flavor development, catalytic degradation of vitamins, and oxidation of lipids. The role of highly bioavailable iron in the off-color development of foods and beverages is not well-understood. The goal of this research was to examine the interaction of iron with simple phenolics and polyphenols. Factors that may affect off-color development, such as pH, oxygen, temperature, and reducing and chelating agents, were evaluated as a model for food products. Our results demonstrated that the iron that reacts with the simple phenolic, catechol, to develop off-color must be in the oxidized state, and the iron is reduced in the presence of catechol. Because this is an oxidation/reduction reaction, the redox potential of all of the components is critical to the color development. Ferrous iron sources with low redox potentials and ferric iron sources with high redox potentials caused off-color development with catechol. Only polyphenols that contain ortho-hydroxyl groups cause off-color development with iron. All of the factors tested affect off-color development and redox potential of the system. Low pH, low oxygen, high temperature, and the presence of reducing and chelating agents inhibited off-color development. To confirm the model, foods that contained these polyphenols were evaluated for off-color development when iron was added. The foods tested reacted similarly to the models of polyphenols with iron. Off-color development was caused by oxidation-reduction interactions between ferric iron and polyphenols that contained ortho-dihydroxyl groups. Ferrous iron needed to be oxidized to participate in off-color development. In addition, methods identified in the models to prevent off-color development were effective in most of the food products examined. Using the ferrous form of iron and maintaining it in its reduced form by lowering pH, removing oxygen, and including reducing agents, it was possible to fortify foods with highly bioavailable iron.