Two experiments with male growing albino rats have been made to find the effect of dietary iodine levels on toxicity and metabolism of methylmercury. In both experiments, rats were divided into 5 groups according to iodine levels. In the first experiment, rats were raised on the diet containing 30 ppm methylmercuric chloride (MMC) (as Hg) for 4 weeks. In the second experiment, rats were raised on the diet containing 10ppm MMC (as Hg) for 37 days, and thereafter they were fed MMC free diets for further 29 days. The results obtained are as follows.
1) On the diet containing 30ppm MMC (as Hg), the clinical signs (hindlimb paralysis) of methylmercury toxicosis appeared in all the rats except for the control during the feeding period of 19 to 29 days. The clinical signs were detected at earlier stages according to the increasing dietary iodine levels.
2) The total intake of MMC up to the appearance of the clinical toxic signs (hindlimb paralysis) decreased with the increase of the dietary iodine levels.
2) The methylmercury concentration in organs (feeding the diets containing 10ppm MMC for 37 days; the liver, brain, thigh muscles and whole body, and feeding of the MMC free diets for further 29 days; the liver, kidneys, brain, spleen, thigh muscles and whole body) was higher in the high iodine groups than in the low iodine groups.
4) In both cases, given the MMC diets for 37 days and thereafter MMC free diets for further 29 days, the total mercury concentration in organs increased proportionally to the increase of the MMC concentration in organs.
5) In both iodine balance examinations, the amount of methylmercury excreted into urines n the high iodine groups was smaller than that in the low iodine groups.

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The present study was conducted to evaluate the biological effectiveness of Zn released from beef meat with proteolytic digestion. Cooked beef meat was hydrolyzed with pepsin at pH 1.0 for 3.5hr, and subsequently the pH was adjusted to pH 7.6, and the suspension of the meat after pepsin digestion was further hydrolyzed for 2hr with trypsin. During the course of the peptic digestion, considerable amount of Zn in cooked meat was released into its digestion medium. Nevertheless, over half of this solubilized Zn was transferred into the undigestive residue by the subsequent tryptic digestion. The observed change of solubility of Zn seems to be caused by alterations in pH. Fractionation of the hydrolyzates with pepsin, or pepsin and trypsin, by Sephadex G-100 column chromatography, indicated that Zn in these hydrolyzates might bind to proteinaceous substances. These results allow us to speculate that the most amount of ingested Zn, being bound to protein-like substances, may be transported into intestinal lumen before absorption.

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In order to evaluate the various results of antioxidant effect of d-tocopherols hitherto obtained and to use them more efficiently as antioxidants in edible oils and fats, the added effects of d-α-tocopherol (α-T), d-γ-tocopherol (γ-T) and d-δ-tocopherol (δ-T) were studied at different concentrations, respectively. The studies were performed using AOM test with lard and corn oil from which d-tocopherols were eliminated previously. Furthermore, the content of d-tocopherols in samples was measured by high-performance liquid chromatography.
The results obtained as follows;
1) Each added d-tocopherol has optimal range of concentration.
2) The order of antioxidant effect of d-tocopherols in lard depends on the concentrations of d-tocopherols added. That is, below 0.03% of addition, between 0.03% and 0.045% and above 0.045%, the effective order is δ-T<α-T<γ-T, α-T<δ-T<γ-T and α-T<γ-T<δ-T, respectively.
3) In the case of 0.02% addition of d-tocopherol to corn oil, the antioxidant effect is shown by the order of δ-T<α-T<γ-T. The same order is obtained with lard.
4) In both of lard and corn oil, linear relationship between POV produced and residual amount of d-tocopherols is observed. The order of the feasibility of each d-tocopherol oxidation is δ-T<γ-T<α-T at any concentrations tested.
5) POV increases abruptly after d-tocopherols were consumed up.
6) It is recognized that the order of antioxidant effect of d-tocopherols is variable. The reason of the variation seems to relate to the test conditions and POV from which AOM value is obtained.

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This study was conducted to evaluate conversion ratio of tryptophan to niacin in healthy young women. Five healthy young women served as the experimental subjects.
The basal diet (tryptophan 0.41g, niacin 2.5mg; determined) prepared from twenty-one food stuffs (tryptophan 0.47g, niacin 5.1mg; calculated from Standard Tables of Food Composition in Japan) was given to the subjects for 5 days as a control period. Just after the control period, a certain amount of tryptophan or niacin was additionaly given for 5 days at a test period to the subjects eating the basal diet.
Urinary N¹-methylnicotinamide and N¹-methyl-2-pyridone-5-carboxamide, as niacin metabolites, of the latter 2 days at each period, were determined. The value of the niacin metabolites in a control period of each subject was subtrated from that of the corresponding test period.
The conversion ratio of tryptophan to niacin was calculated by comparison between the niacin metabolites per 1mg niacin given and the amount of niacin metabolites after administration of 500mg or 1000mg tryptophan.
The calculated ratio of tryptophan was from average of 21.4 to 60.1mg per 1mg niacin for four subjects except one, whose value was extremely high. The average value obtained from the four subjects was 44.7±17.6mg.

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Saccharin has been used as a non-nutritious sweetener in the belief that it is not metabolized in the body and excreted in the urine in unchanged form.
In this paper, a new gas chromatographic method for the micro-determination of saccharin in urine samples is described. The principle of this method is based on the conversion of saccharin to 1, 2-benzisothiazoline-1, 1-dioxide by hydrochloric acid and zinc at 90° and its gas-chromatographic determination (Flame Photometric Detector) after extraction with methylisobutyl ketone. By this method, saccharin in the normal urine samples collected from Kagawa prefecture in 1974, 1978, 1979 was shown to be in the range of 0-5, 963μg within 8hr. Saccharin in the urine samples from diabetic patients was shown to be in the range of 0-25, 600μg in 1980.
When human subjects were received a single oral dose of 66mg saccharin sodium (50mg as saccharin), more than 90% of dose was recovered in the 96 hours-urine. More than 60% of saccharin was recovered in the first 6 hours.

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The zinc contents of 32 samples of foods was determined by non-destructive activation analysis using a high resolution Ge/Li/detector.
The zinc content of cereals ranged from 10.61 to 18.95μg/g, beans from 35 to 47μg/g, vegetables from 1.50 to 7.7μg/g, fish samples from 3.49 to 22.46μg/g, and meat samples from 6.1 to 51.58μg/g.

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Examining an effect of dietary lead and cadmium, male growing rats were given lead (50, 500ppm) and/or cadmium (10, 50ppm) containing diets for 20 days. A simultaneous ingestion of dietary lead and cadmium revealed an additive toxicity on growth and hemoglobin concentration.
Whereas, metal concentrations in tissues suggests that cadmium inhibits an absorption of lead (or stimulates an excretion) but lead does not cause any inhibition of cadmium absorption (or increase of excretion).

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Twenty-four kinds of domestic margarine (“soft” types 13, “carton-packed hard” types 9, and “parchment-packed” types 2) were analyzed for fatty acid composition, sterols and tocopherols, and nutritionally evaluated with some indices characterizing fats.
1) Average content of linoleic acid was 38.21% in the soft, 20.61% in the hard, and 10.85% in the parchment-packed type. Of these, four, samples were of the high-linoleic type containing above 45%.
2) Average content of total trans-acids was 14.49% in the soft, 19.18% in the hard, and 28.95% in the parchment-packed type. Of these, two samples were the “zero-trans” margarine containing no trans-acids.
3) The total tocopherol content was 20-50 mg/100g, optimum levels of their antioxidative effect. It was also demonstrated that α-tocopherol was contained in an amount of 20mg/100g or more in the high-linoleic types.
4) In the high-linoleic types, the ratio of the polyunsaturated to saturated fatty acids was 2.90 and the Keys' plasma-cholesterol variat on estimate index was -38.8, indicating to have a blood cholesterol lowering effect. The ratio of vitamine E to polyunsaturated fatty acids was 0.47 or 0.49.

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