• Nutritional Sciences
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• v.3 no.2
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• pp.71-76
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• 2000

Effects of extrusion processing on zinc bioavailability in a product made from 85% semolina and 15% soy protein concentrate were determined using in vitro and in vivo techniques. Soluble and dialyzable zinc contents of the extruded product were 15.3 and 13.0 $\mu$g/g, respectively, compared to 15.6 to 15.0$\mu$g/g in the raw (unprocessed) ingredients. Zinc bioavailability in diets in which all of the zinc (14ppm) was provided either by the extruded product or by its raw ingredients was determined in two groups of male Sprague Dawley rats. No differences were found in concentrations of zinc in plasma, liver and femur between rats fed the two experimental diets. Apparent zinc digestibility was similar for both diets. These results are consistent with the in vitro results showing no effect of extrusion processing on zinc bioavailability.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.3
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• pp.439-452
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• 2005

Zinc is ubiquitous in all living cells. Structural and catalytic properties of cellular enzymes are zinc dependent. Zinc deficiency leads to a variety of pathological abnormalities with immune impairment. It is an established fact that nutritional status contributes to overall immune response of individuals. Outcome of zinc deficiency on immune system is so drastic that it is difficult to conceive at the first instance. Zinc supplementation has been advocated to prevent diarrheal disease in children with poor nutritional status. The bioavailability of zinc depends upon its sources. Moreover it varies between monogastrics and ruminants. Controversy still prevails between inorganic and organic sources of zinc with respect to their superiority in bioavailability. Zinc exerts immunostimulatory effects in various laboratory and farm animals. Animals having congenital zinc deficiency diseases like A46 lethal trait usually die due to impairment of the immune system unless treated with zinc. The immune mechanism of zinc and its effect on animals and man are discussed. Zinc has been considered as extremely safe at higher therapeutic doses, but does not provide any beneficial effect but rather may cause immunosuppression. More recently, zinc has been prescribed for immunodeficient hosts, to modulate the immune system so that to a certain extent it can combat against opportunistic pathogens.

• Journal of Nutrition and Health
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• v.30 no.4
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• pp.406-414
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• 1997

It has been known that dietary phytate decreases the absorption of body zinc pool which is composed of the dietary and endogenous zinc in the body. The purpose of this study was to examine the effect of phytate on the absorption of total bodyzinc in Zn-depleted rats. Rats were Zn-depleted with either low(0.8%) or high(1.6%) Ca diet containing sodium phytate for 4 weeks. After zinc depletion, rats were assigned into phytate or non-phytate dietary groups within each low-or high-Ca dietary group. ant feces were collected for 2 weeks of the initial collection and 1 week after dietary crossover, during which the phytate and the non-phytate diet was switched over within the same Ca group. The content of Zn and Ca measured by atomic absorption spectrophotometer and phytate content was analyzed. food intake was higher in the high Ca group than in the low Ca group(p <0.0001), and was also higher in the non-phytate group than in the phytate group(p <0.0001). Food intake and phytate level affected body weight gain in rats(p <0.0001). Zinc excretion in the total feces was higher in the phytate group than in the non-phytate group at both low and high Ca level(p <0.0001), except during the crossover collection period in high Ca group. Calcium, however, didn't show any synergistic effect on phytate effect(p <0.05). This study showed that phytate decreased the absorption of total body zinc at both low and high Ca levels in Zn-depleted rats. A large portion of total body zinc originated from the endogenous zinc pool in these rats. The results of the present study showed the same effect of phytate on the endogenous zinc in Zn-depleted rats as in a previous study, confirming that phytate adversely affects zinc bioavailability, especially under marginal and poor zinc nutrition.

• Journal of Veterinary Science
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• v.24 no.1
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• pp.3.1-3.13
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• 2023

Background: Zinc (Zn) is an essential cofactor for physiological homeostasis in the body. Zn oxide (ZnO), an inorganic compound that supplies Zn, exists in various sizes, and its bioavailability may vary depending on the size in vivo. However, comparative studies on the nutritional effects of micro-sized ZnO (M-ZnO) and nano-sized ZnO (N-ZnO) supplementation on Zn deficiency (ZnD) animal models have not been reported. Objectives: This study investigated the nutritional bioavailability of N-ZnO and M-ZnO particles in dietary-induced ZnD mice. Methods: Animals were divided into six experimental groups: normal group, ZnD control group, and four ZnO treatment groups (Nano-Low, Nano-High, Micro-Low, and MicroHigh). After ZnD induction, N-ZnO or M-ZnO was administered orally every day for 4 weeks. Results: ZnD-associated clinical signs almost disappeared 7 days after N-ZnO or M-ZnO administration. Serum Zn concentrations were higher in the Nano-High group than in the ZnD and M-ZnO groups on day 7 of ZnO treatment. In the liver and testis, Nano-Low and Nano-High groups showed significantly higher Zn concentrations than the other groups after 14-day treatment. ZnO supplementation increased Mt-1 mRNA expression in the liver and testis and Mt-2 mRNA expression in the liver. Based on hematoxylin-and-eosin staining results, N-ZnO supplementation alleviated histological damage induced by ZnD in the testis and liver. Conclusions: This study suggested that N-ZnO can be utilized faster than M-ZnO for nutritional restoration at the early stage of ZnD condition and presented Mt-1 as an indicator of Zn status in the serum, liver, and testis.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.7
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• pp.467-472
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• 2009

Seedling growth test is used to assess toxicity of nanoparticles (NPs). This study evaluates toxicity of zinc, zinc oxide NPs on Cucumis sativus using two methods; phytagel and filter paper. From the comparison, phytagel method prevents precipitation of water insoluble NPS. Seeding length was negatively related to the exposed concentration of Zn, ZnO NPs in filter method. The median effective concentrations (EC50) for C. sativus exposed to Zn, ZnO NPs were estimated about 598, 600 mg/L in filter method. Bioaccumulation increased with the exposed concentration of Zn, ZnO NPs in only filter method. The results showed that the filter paper method was much better protocol than phytagel method.

• Journal of Nutrition and Health
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• v.39 no.3
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• pp.252-263
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• 2006

Zinc is an antioxidant trace mineral, scavenging free radicals and known to be involved in inflammatory reactions. The prevalence of atherogenic diseases such as coronary heart disease (CHD) are increasing in Korean adults of middle age and elderly. The increased cell damage from free radicals and inflammation have been implicated in etiology of CHD, and the evidence is accumulating that low zinc status is involved in the prevalence of this inflammatory atherogenic disease. However, little is known about the zinc status of Korean CHD and its relationship with dietary zinc intake and zinc bioavailabilty. In this study the serum zinc levels of male patients with CHD over 40 yrs. were compared with that of healthy adult males and its associations with dietary zinc intake and zinc bioavailabilty affecting factors were examined. Serum zinc level was measured by HANARO research reactor using neutron activation analysis (NAA) method. The overall proportion of patients with zinc deficiency, serum zinc concentrations below $74.0{\mu}g/dL$ was 32.8% compared to the 10.3% in healthy group. The average serum zinc levels were $80.7{\mu}g/dL\;and\;88.3{\mu}g/dL$ in patients and healthy group, respectively, showing significantly low zinc status in CHD patients compared to healthy group. The intake of nutrients such as energy, carbohydrate, iron, and copper of CHD patients was significantly higher compared to that of the healthy group. In addition, the intake of calcium, iron, and protein from vegetable foods was significantly higher in CHD patients than that of healthy group. The dietary zinc intake was $12.7{\pm}4.5mg$ and $11.5{\pm}6.9mg$ in CHD patients and control group, respectively, which showed no difference. The phytate intake of patients group, which is 1389.0 mg, was significantly higher than the control group which showed 1104.8 mg. However, the ratio of phytate: zinc or phytate * calcium. zinc per 1000 kcal energy intake did not show any difference between two groups. The serum zinc levels did not show any correlation with zinc or factors that affect the bioavailability of zinc. The dietary factors influencing the zinc status were not found in CHD patients.

• Journal of Nutrition and Health
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• v.36 no.9
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• pp.950-959
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• 2003

To assess zinc status by dietary intake and urinary excretion of preschool children in Busan and to evaluate the relationship of intakes of food and nutrient with urinary zinc excretion, zinc food frequencies of 40 common foods affecting intakes of zinc by food fequency method, nutrient intake by 24hr recall and 24hr urinary zinc excretion were measured with 97 preschool children. The mean zinc intake was 4.29 mg and 43.0% of RDA. The mean zinc intake per 1,000 kcal was 3.09 mg.97.9％ of subjects had zinc intake less than 75％ of RDA. Grains food group was the primary source of zinc intake and supplied 38.9% of the total daily zinc intake. Altogether, plant food products supplied 49.7% of zinc intake. The mean urinary zinc excretion and zinc excretion per gram of creatinine were 0.19 mg and 1.00 mg respectively. The urinary zinc excretion showed positive significant correlations with height and weight (p < 0.05, p < 0.05) , urine volume and urinary creatinine excretion (p < 0.05, p < 0.001) , urinary zinc excretion per creatinine (p < 0.001) , urinary zinc excretion per weight (p < 0.001) , intakes of energy and carbohydrate (p < 0.05, p < 0.01) and usual intake of zinc from eggs food group (p < 0.05) . In conclusion, these results show that the zinc intake of preschool children is low and that sources of dietary zinc are mainly plant foods, suggesting low bioavailability. So nutritional education is needed in order to inc-rease usual intake of animal food group. Interpretation of urinary zinc excretion data is complicated by current uncertainty about "normal" zinc level at this age group. Further studies are needed to obtain extensive data on urinary zinc excretion for this age group.age group.

• Journal of Nutrition and Health
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• v.31 no.8
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• pp.1324-1377
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• 1998

This study was conducted for two purposes ; (1) to develop a database for zinc levels in commonly usef Korean food items ; and (2) to calculated the zinc intake fo Korean adults living in a rural area. The currently used Korean food compositinotable was supplemented in term sof zinc content using several methods ; (1) analyzing 98 Korean Food items frequently consumed by Korean adults living in rural area. ; (2) adapting values from U.S Minnesota for 71 items ; and (3) imputing values from similar food for 282 items. A new zinc nutrient databse was constructed including zinc contentrs of 1,195 food items. Zinc intake of rural Korean adults was estimated by a 240hours recall method from 2 ,037 adults over 30 over 30years of age in Yeonchon -gun , Kyunggi province of Korea. Mean daily zinc intake of all subjects was 61mg an dmean intake level of males (7.0mg/day, 46.85 of RDA) was significantly thigher than females(5.2mg/day, 43.0% of RDA). Subjects in their 40's had the highest zinc intak ewhile those over 70 years of age consumed the least amount of zinc. The food group that contributed most to the dietary ainc intake of subjects was cereals and grain products supplying 38% of total zinc intake. The next most important group for zinc intak ewas the meat, poultry , and product group supplying 26% ot total intake. This group was followed by fishes and shellfishes, legumes and their products, and vegetales . For individual food items , reicecontribued most, supplying 27% of total zinc intake follwoed by beef(10%) and prok(9%) . Altogether, plant foods supplied 68% of zinc intake suggesting that the bioabailability of dietary ainc is low. In conclusion, these results show ethat the zinc intake of rural Korean adults is low and that sources of dietary zinc are mainly plant foods, suggesting low bioavailability . Further studies are needed to determine zinc intake and status of Korean population. The zinc database developed in this study will be very valuable for such studies.

• Journal of Nutrition and Health
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• v.30 no.4
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• pp.394-405
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• 1997

Endogenous zinc is important for maintaining zinc homeostasis because the size of endogenous zinc pool is almost 3-4 times bigger than that of dietary zinc. The purpose of this study was to examine the phytate effect on the reabsorption of endogenous zinc and the additional Ca effect on the phytate effect. Rats were fed a casein-based diet with added sodium phytate containing either high(1.6%) or low(0.8%) Ca concentrations for 4 weeks to reduce the body zinc pool. After the depletion period, $^{65}$ Zn was given by intraperitoneal injection to label the endogenous zinc pool. Rats were then assigned into phytate or non-phytate group within the same Ca group. feces were collected for 2 weeks of the initial collection period and 1 week after dietary crossover. The ratios of excreted fecal $^{65}$ Zn radioactivity of phytate group non-phytate group were determined as a measure of the phytate effect on the endogenous zinc. Mean fecal $^{65}$ Zn radioactivity was higher in the phytate group than in the non-phytate group during the entire 3 weeks of the collection period in the low Ca group, and during the initial collection period in the high Ca group(p <0.0001). This study showed an adverse phytate effect on endogenous zinc at both high and low dietary Ca levels. Elevated dietary Ca levels showed a synergistic effect on the phytate effect on endogenous zinc(p <0.05). These results imply greater phytate effect on zinc homeostasis rather than on zinc bioavailability through complexing with the endogenous zinc which is larger portion than the dietary zinc on zinc homeostasis.

• Journal of the Korean Dietetic Association
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• v.13 no.4
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• pp.301-310
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• 2007

The purpose of this study was to analyze the relationships among zinc status, protein and phytate intake, and diabetic control indices of type 2 diabetic women. The mean age and the duration of diabetes were respectively 57.9±6.9 years old and 8.0±6.5 years. The mean daily energy intake of diabetic subjects was 1562 kcal. Both the zinc intake (6.2mg/day) and the zinc %RI (% of The Recommended Intake for zinc: 79.5%) of the diabetic participants were significantly lower than those of the control group (respectively p<0.01). As for the diabetic group, the higher the energy intake (kcal/day), the higher were the zinc intake (p<0.001) and %RI for zinc (p<0.001). Zinc intake was positively correlated with the protein (p<0.001), animal protein (p<0.001), and fat intake (p<0.001), but negatively correlated with the carbohydrate intake (p<0.001). Foods with high amount of phytate were the major source of zinc (p<0.01), but did not contribute to high zinc densities. The urinary zinc excretion was twice as high as in the diabetic group compared to the control group (p<0.001). In addition, the urinary zinc loss was positively correlated with the duration of diabetes (p<0.05), hyperglycemia (p<0.001) and insulin resistance (p<0.05). %RI for zinc was negatively correlated with the HbA1C (p<0.05). These results lead us to conclude that the appropriate intake of energy controlled by diet therapy could improve the total zinc intake and %RI for zinc in diabetic women. Also, normal blood glucose level controlled by diet therapy could improve the hyperzincuria. Dietetic practitioners should encourage consumption patterns that provide zinc-rich foods in the form of animal protein to improve the bioavailability as well as the total daily intake of zinc.