The occurrence of pellagra in an endemic form in a population subsisting mainly on the millet jowar (Sorghum vulgare) has been briefly reported by Gopalan & Srikantia (1960). Both jowar and maize have one common feature with regard to their amino acid composition, namely a high content of leucine. The possible role of amino acid imbalance resulting from a relative excess of leucine in the pathogenesis of pellagra was therefore suggested. In the present investigation the effects of the oral administration of leucine on the metabolism of tryptophan and nicotinic acid have been studied. METHODS Experimental procedure. Six patients suffering from pellagra (pellagrins) and six apparently normal male adults, between the ages of 25 and 45 years, formed the subjects for the study. They were kept in hospital and put on a standard diet, based on rice, wheat flour, dhal and vegetables, providing them with approximately 2300 kcal., 50 g. of protein and 50 g. of fat/day. The protein was derived entirely from vegetable sources, and constituted about 8 % of the total calories. Preliminary studies had indicated that the urinary excretion of some nicotinic acid metabolites usually became stabilized on this diet by the third or fourth day. Therefore 24 hr. collections of urine were made on the fifth, sixth and seventh days of the standard diet. The subjects were then given 10 g. of pure L-leucine daily, in a single dose, taken with one of the main meals of the day, for five days. Then 24 hr. urine collections were again made on the second, third, fourth and fifth days of the supplementation with leucine. The supplement of leucine was then withdrawn, but the collection of urine samples was continued for 4 more days. The samples of urine were collected over 15 ml. of acetic acid and analysed without delay.In four other normal volunteer adults the effects of simultaneous ingestion of (a) tryptophan and leucine, and of (b) nicotinic acid and leucine, on the urinary excretion of tryptophan metabolites were studied. Subjects were maintained on the standard diet described above, and 24 hr. urine samples were collected on the fifth, sixth and seventh days. On the morning of the eighth day, at 9 a.m., 5 g. of DL-tryptophan was given orally, and the urine was collected till 9 p.m. At 9 p.m. another load at 5 g. of DL-tryptophan was given, and urine was collected for the next 12 hr. Samples (24 hr.) were collected from the morning of the ninth day for the next 3 days. The subjects were then given 5 g. of leucine twice a day for 5 days; on the fifth day they received 5 g. of tryptophan in addition to the leucine. Urine collections were made in the manner described above. For the load test with nicotinamide the experimental procedure was identical except that 100 mg. of nicotinamide/dose was used instead of tryptophan.
The effect of milling on the mineral and trace element composition of raw and parboiled grain samples of 16 varieties of rice was investigated. Varietal, locational and seasonal differences in the nutrient composition of brown rice were noted. The mean values for different nutrients per 100 g brown rice were total ash 1.37 g, phosphorus 349 mg, magnesium 157 mg, calcium 18 mg and iron 2.16 mg and in pg per g samples, zinc 14.3, manganese 11.0, copper 2.39, molybdenum 0.775 and chromium 0.088. Parboiling per se had no effect on the composition of brown rice. The degree of milling and the initial concentration of the nutrient in the grain determined the magnitude of loss on milling both in raw and parboiled grain. Percent losses of different nutrients on 5 and 10 % milling of raw rice respectively were total ash 40,62; iron 51, 67; magnesium 40,64; calcium 36, 57; iron 54,64; copper 26,45; manganese 48, 56; molybdenum 24, 34; chromium 57, 69; and zinc only 2.8, 4.6. Zinc in rice grain was uniformly distributed and a major portion of other nutrients was concentrated in the outermost 2.5 % surface layers of the grain. Parboiling appeared to have altered the distribution of some nutrients in rice grain except for zinc, magnesium and copper. Milling losses for other nutrients were therefore significantly lower in parboiled than in raw rice.
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