The relationship between dietary fiber and lipid intake was investigated in both female students and elderly women in metropolitan Tokyo. Furthermore, the characteristics of their foods were analyzed and compared between the two groups. Dietary fiber intake by elderly women was 17.2g/day, which was significantly higher than that by young women (11.3g/day) (p<0.001), whereas lipid intake did not differ significantly between the two groups. The ratio of lipid to total energy intake was 24.5% in elderly and 27.8% in young women. The intake of dietary fiber increased in parallel with lipid intake in elderly women (r=0.52, p<0.001), but no clear correlation between dietary fiber and lipid intake was observed in the young women, although it showed a positive correlation. The main source of dietary fiber was cereals and vegetables in both groups, but vegetable intake was significantly higher in the elderly than in the young women (p<0.001). A positive correlation was observed between vegetable intake and intake of fat and oil in the elderly (r=0.26, p<0.05), but not in the young women. However, a positive correlation was observed between vegetable, fat and oil intake at breakfast (r=0.28, p<0.01) and dinner (r=0.25, p<0.05) in elderly women, and at lunch in young women (r=0.44, p<0.001). These results demonstrate that the lipid-rich diet of younger and elderly women resident in a metropolitan area is not always low in dietary fiber. It is considered that changes in food preference are occurring in both young and elderly people, and that processed foods and frozen foods containing high lipid are consumed easily.

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The National Nutrition Survey estimates the average dietary intake per capita on the basis of household food consumption data. Dietitians at local public health centers manually execute the coding of food names, the total amount consumed, and the proportion shared by family members to compute the nutrient intake of individual subjects. The coded data are then checked and corrected by other dietitians at prefectural departments. We examined sources of error in both procedures, and described the frequency of errors and their effect on the calculation of energy and nutrient intake by using a sub-sample of 132 households, including 445 family members, surveyed in 1995. The errors in coding the foods and the total amount consumed, including no-coding for a specified food, occurred at 1.61 per household, and those in coding the proportion shared by family members were 0.19 at the public health center level. The frequencies for prefectural departments were 1.57 and 0.16 per household, respectively. This suggests that the present data-handling procedures are not satisfactory. In conclusion, we recommend that a new system for coding and data entry using personal computer software should be adapted by public health centers. Such a system should have automatic error checking procedures by incorporating a food code list and establishing upper limits for the acceptable values for each food.

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Previously, we observed the inhibitory effect of phosphorylated oligosaccharides (PO) from potatostarch on the formation of calcium phosphate precipitate. PO were composed of two fractions: PO-1 and PO-2. The former was maltooligosaccharide bound to one phosphate molecule, and the latter was maltooligosaccharide bound to at least two phosphate molecules. PO-2 had a stronger inhibitory effect. In the present study, we investigated the effect of PO-2 feeding on calcium utilization in rats. Five-week-old rats were fed a calcium diet (0.52% of calcium) containing 5% PO-2 for two weeks. The apparent calcium absorption ratio and apparent retention ratio during two periods (days 3-6, days 10-14) were significantly lower in the rats fed the PO-2 diet than in those fed the control diet. The results of a breaking-force test and the calcium content of the femur did not differ significantly between the two groups. Whole cecal weight was significantly higher in the rats fed the PO-2 diet, and the amounts of short-chain fatty acid in the cecal content were significantly increased; cecal pH was not changed. There was no apparent correlation between the calcium-solubilizing effect of PO-2 in vitro and the degree of calcium absorption in vivo.

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Six-week-old male Wistar rats weighing about 130g were given normal, calcium (Ca)-free and mineral-free diets for seven days, and then bled from the tail vein at 0, 0.25, 0.5, 1, 2, 4, and 8h after ovenight food deprivation (for 16h). The rats were then orally administered 0, 20, 40, or 100mg Ca/rat, and the intestines were removed immediately after decapitation 8h later. When 20mg Ca was supplied orally, the plasma Ca level reached maximum after about 1h in rats given the normal diet, and after about 2h in the rats given the Ca-free and mineral-free diets, although the levels were higher in the order normal, Ca-free, and mineral-free. After the 40-mg dose, the plasma Ca level became maximal after about 2h irrespective of diet, the highest level being attained in rats given the mineral-free diet, followed by those given the Ca-free and normal diets. With the 100-mg dose, the plasma Ca concentration was markedly increases for the first 30min after administration, irrespective of diet, and then decreased slightly in rats given the normal diet and increased slightly in rats given the Ca-free diet, although the level in the rats given the mineral-free diet increased linearly. All rats given the mineral-free diet died within 24h after Ca supply. The amounts of Ca remaining in the intestines were generally inversely correlated with the plasma Ca concentration, irrespective of diet. Kinetic analysis of Ca movement suggested that the apparent volume of distribution was closely related to the observed results.

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The effect of long-term dietary calcium supplementation on fecal mineral excretion was examined in four-week-old male Wistar rats. The rats were divided into two groups, and fed different doses of calcium (0.5% and 1.5% calcium) in the diet for 10 weeks. Feces were collected during 5 days after 3 and 10 weeks, and fecal weight and mineral contents (Ca, Mg, P, Fe, Cu, Zn, Na, K) were measured. Final weight and food efficiency rate were found to decrease with dietary calcium supplementation. A high calcium level in the diet increased the fecal weight and fecal excretion of magnesium, phosphorus, iron and copper, but did not affect the fecal excretion of zinc, sodium and potassium. Apparent absorption of magnesium, phosphorus and iron decreased with dietary calcium supplementation. It is considered that calcium supplemenation disturbed iron absorption with resulting fecal excretion of iron. This phenomenon reflected the lower hemoglobin value in the high-calcium diet group. These results suggest that long-term dietary calcium supplementation in rats may deplete magnesium, phosphorus and iron.

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We have demonstrated previously that concurrent addition of demineralized onion fiber (DOF), demineralized wheat bran or powdered polystyrene foam to a basal diet containing Fe (II) in the form of ferrous sulfate (20mgFe/kg diet) significantly improved hemoglobin regeneration in anemic rats which had been maintained on an iron-deficient diet for 3 weeks. A balance study revealed that the addition of DOF improved the apparent absorption of Fe (II). In the present study, we examined the effect of DOF on iron absorption from ⁵⁹Fe-labeled ferrous sulfate solution (20mg Fe (II)/L) placed in rat duodenal loops. The addition of DOF (10mg/mL) to the labeled medium accelerated the absorption of iron irrespective of whether the rats had been maintained on an iron-deficient diet for 14 or 42 days or on an adequate diet (41mg Fe/kg diet) for 10 days.

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In diets served at a hospital, the effects of sterilization on the contents of 20 nutrients were determined. The measured nutrients were protein, calcium, phosphorus, iron, sodium, potassium, magnesium, zinc, copper, manganese, retinal, β-carotene, vitamin B₁, vitamin B₂, vitamin C, vitamin E, cholesterol, dietary fiber, fat and fatty acid. The contents of inorganic compounds in the sterilized diet exceeded 90% of those in a normal diet, and the contents of vitamins were low. However, the vitamin B₂ level was 97.2% of normal. Loss of retinal, β-carotene, vitamin B₁, vitamin C and vitamin E resulting from diet sterilization was regarded as significant (p<0.01).

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[in Japanese]

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