• Asian-Australasian Journal of Animal Sciences
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• v.24 no.7
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• pp.940-945
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• 2011

In order to determine whether oxalate from grasses affects feed intake, blood calcium (Ca) and other blood parameters of adult sheep, two feeding trials were conducted. In Trial 1, one group of sheep received guineagrass (0.47% soluble oxalate) and another group received setaria (1.34% soluble oxalate) for 28 d. In Trial 2, one group of sheep received guineagrass while another group received the same grass treated with an oxalic acid solution (at a rate of 30 g oxalic acid/kg dry matter of hay) for 72 d. All sheep received concentrate mixtures (0.5% of body weight) throughout the experiment. In both trials, it was observed that plasma Ca concentration (11.0-11.7 mg/dl) was significantly (p<0.05) lower in sheep fed high oxalate-containing grasses than in sheep fed low oxalate-containing grasses (12.4-13.7 mg/dl). No differences (p>0.05) were observed in concentrations of magnesium, phosphorus and parathyroid hormone in plasma between the feeding of low and high oxalate-containing grasses. In addition, no differences (p>0.05) were observed in roughage dry mater (DM) intake, total DM intake or body weight of sheep. This study suggests that sheep may consume oxalate-rich forage, but Ca bioavailability may decrease with increasing oxalate levels in the ration.

• Journal of Nutrition and Health
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• v.44 no.2
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• pp.101-111
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• 2011

It is controversial whether low calcium intake, commonly associated with osteoporosis, results in calcium accumulation in soft tissues. This study was conducted to investigate the effects of low calcium (Ca) and oxalate (ox) intake on soft-tissue Ca deposits and bone metabolism in ovariectomized (ovx) rats. Eight week old female Sprague-Dawley rats were ovariectomized and divided into four groups. The rats were fed experimental diets containing low (0.1%, w/w) or normal (0.5%, w/w) Ca with or without sodium oxalate (1%, w/w); Sham/NCa, Ovx/NCa, Ovx/LCa, Ovx/NCa-ox, Ovx/LCa-ox for 6 weeks. All ovx rats showed a remarkable increase in body and tissue weight, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, blood urea nitrogen, alkaline phosphatase, and decreases in weight, ash, and Ca contents, as well as bone breaking force compared to those in sham rats. Serum Ca concentration was not significantly affected by dietary Ca levels or ox intake. Kidney Ca, ox acid content, and microscopic Ca deposition increased remarkably in the Ovx/LCa-ox group compared to those in the other groups. Ca content in the spleen and aorta also increased significantly, but the weight contents, Ca, bone breaking force, and Ca and oxalic acid in feces decreased significantly in the Ovx/LCa-ox group. Serum parathyroid hormone levels were not significantly different among the groups. These results indicate that low Ca intake decreased bone mineral content and increased Ca deposits in soft tissues, which was aggravated by ox intake in ovx rats. Thus, high ox intake may result in a kidney disorder in patients with osteoporosis who eat a low Ca diet.

• Food Science and Biotechnology
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• v.17 no.5
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• pp.1122-1127
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• 2008

A high dietary oxalate intake may lead to calcium oxalate (CaOx) kidney stones in the gastrointestinal tract. Most soy foods contain high concentrations of oxalate and/or phytate. This study analyzed the changes in oxalate (Ox), phytate ($InsP_6$), and calcium (Ca) during soymilk processing from the seeds of Korean recommended soybean cultivars (cvs). The contents of Ox, $InsP_6$, and Ca in 21 cvs ranged from 14, 108, and 148 to 231, 279, and 246 mg/100 g of dry seed, respectively. Seven cultivars were selected from the 21 cvs by the distributions of Ox, $InsP_6$, and Ca. Then, each contents of soymilk prepared from the 7 cvs were determined. All contents were lower in soymilk than in seeds, but the Ox to $InsP_6$ ratios changed from varying ratios (0.1-0.8) to normal ratios (0.8-1.0) in all cvs except 'Paldalkong'. Consequently, during soymilk processing, the Ox content was decreased and the $InsP_6$ content was remained higher than the Ox content although the Ox was likely to be less reductive than the $InsP_6$. These results may provide better information for minimizing the risk of formation of Ox kidney stones due to consumption of soy products.

• The Korean Journal of Food And Nutrition
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• v.7 no.4
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• pp.307-317
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• 1994

The study analyzes relationship between Increasing tendency of urinary stone patients and changes of food intake through statistical data during recent 10 years(1982∼1991) in Korea. In four university hospitals, the number of urinary stone patients increased 2.5 times during the period. Study statistics showed sex ratio of male and female patient as 2.1 : 1.The types of the urinary stone of each patient were broad and mostly Ca and others(85.8%), and Ca oxalate stones were 65.2%. The incidence of patients with hypercalciuria and hyperuricosuria was observed in the Ca stone patients than in normal person. The same period showed increase of total monthly household expenditure as 3.2 times, food as 2.5 times and medical expenses as 2.4 times : The food expenditure decreased relatively In the expenditure composition. Daily hood consumption (g/person) increased as 3 times in meat, 4 times in milk, 2.4 times in seaweeds. Daily total Ca nutrition consumption was undulant and became 1.1 times during the same period. Daily food supply (g/person) was increased 1.9 times in meat, 1.4 times in spinach. However, anchovy, laver, brown seaweed, herring and makerel showed undulant tendency. Relationship (correlation coefficient) between the increase of urinary stone patients and of food intake were studied as follows. In the case of food intake, the relative index was 0.923 in seaweeds, 0.865 in meat and 0.대27 In milk And In food supply, the relative index was 0.855 in purine group which constitute meat, anchovy, herring and makerel. The relative index of Ca components which constitute anchovy, laver, brown seaweed and shrimp was 0.270. In the case of nutrition intake, the relative index was medium in protein(r: 0.443) and In animal protein (r: 0.488) but was negative in Ca(r: -0.028).

• Journal of Food Hygiene and Safety
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• v.7 no.4
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• pp.165-172
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• 1992

Among the nutrients of biological importance, minerals are of particular interest in human nutrition because the range of adequate intake is so narrow. As the results of a series of interaction experiments between dietary fiber sources and minerals, there are many inconsistencies in the experimental data regarding the effect of dietary fibers on mineral bioavailability. the mechanism by which dietary fiber might influence mineral absorption is related to its physicochemical properties. These properties involve the ability of dietary fiber to (1) act as a weak cation exchanger, (2) decrease transit time, (3) dilute mineral concentration by increasing fecal bulk and (4) resist digestion in the large bowel. Regardless of the large number of human and animal studies available, a carful review of these publications dose not provide the answer as to whether the adverse effect of dietary fibers on mineral absorption is the fiber itself or some associated dietary factors( e.g. phytate, oxalate, ascorbate, citrate and protein, mineral-mineral interaction, etc) that are responsible for this action. As a result of the complexity of interaction that may take place between minerals. dietary fiber, and other component of food ; it becomes very difficult to blame fiber alone as a negative factor of mineral nutrition. We absolutely need more research with advanced tools rather than metabolic balance study.