Search

The correlations between the mean of 4 d weighed intakes of lutein, lycopene and beta-carotene and mean plasma concentrations during each of the four seasons were lutein r 0.64, lycopene r 0.47 and beta-carotene r 0.45. Intake was not significantly correlated with plasma concentrations during every seasonal time-point. There was a significantly higher intake of lutein during the spring compared with summer and autumn, lycopene intake was significantly higher during the summer and autumn and there were no significant seasonal differences in beta-carotene intake. There were, however, significant seasonal differences in plasma carotenoid concentrations, the highest levels occurring between May and October. There were large inter- and intra-individual variations in intake and plasma concentrations of carotenoids. BMI was inversely correlated with plasma beta-carotene (r-0.41). The findings suggest that plasma carotenoid concentrations are indicative of dietary intake, but the large intra-individual variation in plasma concentrations indicates that any assessment of longer-term status from data at any one time-point should be treated with caution.

1. The influence of trace-nutrient-binding proteins on the growth of coliforms, streptococci and lactobacilli in the gastrointestinal tract was examined in neonatal rabbits delivered germ-free and dosed with an artificial flora (ESL), or born conventionally and dosed with ESL or rabbit faeces. 2. In the stomach and small intestine of both gnotobiotic and conventional animals the counts of coliforms were usually atypically high and those of streptococci were always low. In the colon the counts of coliforms and streptococci were high. Lactobacilli usually became established in the gut of the gnotobiotic animals but were not found in the conventional rabbits. 3. Sterilization (freeze-drying followed by gamma-irradiation) of the milk decreased its capacity to bind added iron by 45% and vitamin B12 by 30%. When compared with raw milk, feeding of radiation-sterilized milk did not affect the viable count of coliforms and streptococci in the gut of gnotobiotic animals. 4. Saturating the nutrient-feeding proteins in milk with Fe, folic acid and vitamin B12 had no effect on the numbers of coliforms, streptococci and lactobacilli recovered from the intestine.

1. A study was made of absorption of [58Co]cyanocobalamin in suckling piglets. Cyanocobalamin given at birth and at 7 d of age was efficiently absorbed from the intestine and retained within the body, mostly in the liver. A 10 mug test dose was absorbed no less efficiently than 2-5 mug, despite the virtual absence of intrinsic factor in the gut. In piglets given a 10 mug test dose at different ages between 2-5 and 56 d, there was a marked decrease in the efficiency of retention between about 7 and 21 d of age. 2. Vitamin B12-binding capacity in the gastric muscosa increased with age, from 40 ng at birth to about 2000 ng at 14 d and 7000 ng at 35 d. This binder-protein was largely endogenous, whereas much of the unsaturated binder-protein in intestinal mucosa was apparently derived from milk. 3. The chyme in the stomach and small intestine contained unsaturated binder-protein, partly endogenous and partly deriving from milk, which prevented uptake of added [G-3H]-cyanocobalamin into the 'solids' phase of the intestinal contents. The intestinal chyme contained large numbers (log10 7-0--9-1/ml) of bacteria, some of which were isolated and shown to take up cyanocobalamin or folic acid or both. 4. The finings are discussed in relation to the concept that for some days or wekks after the cessation of transport of inact protein across the neonatal gut epithelium ('closure'), protein-bound vitamins may continue to be taken up into the epithelial cells and there released for transport into the circulation. It is concluded that unsaturated vitamin-binders may strongly influence the ecology of the intestinal microflora.

1. The B-vitamins in milk from baboons (Papio cynocephalus) at various stages of lactation were measured microbiologically. 2. Mature milk contained, on average (microgram/ml): thiamin 0.18 riboflavin 0.74, nicotinic acid 3.2, folate 0.03, vitamin B6 0.70 vitamin B12 0.002, pantothenic acid 2.63, biotin 0.0065. 3. Colostrum contained much less vitamin B6 and pantothenic acid than mature milk; otherwise, there were only slight changes in composition as lactation progressed. Neither these changes, nor the absolute values, resembled those for human or cow's milk. 4. The average daily secretion of B-vitamins in milk represented less than 10% of the mother's dietary intake; that of folate was less than 0.5% of the mother's dietary intake. 5. Baboon milk was calculated to provide infants with approximately the following quantities of B-vitamins (/d): thiamin 0.06 mg, riboflavin 0.25 mg, nicotinic acid 1.1 mg, folate 10 microgram, vitamin B6 0.25 mg, vitamin B12 0.7 microgram, pantothenic acid 0.9 mg, biotin 2.2 microgram.