[Amount of nitrate and nitrite in daily menus containing more than 350 g of vegetables].

The contents of nitrate and nitrite in menus containing more than 350 g of vegetables per day were investigated. The amounts of vegetables in menu A developed by female students and menu B taken from a recipe book were 350+/-2 g and 457+/-77 g, respectively. The average content of the nitrate was 321.0+/-139.3 mg (104.2-636.9 mg) in menu A, and 245.7+/-90.7 mg (140.1-507.3 mg) in menu B. Sixteen and thirteen samples exceeded the ADI in menus A and B, respectively. This may be because menu A contained more raw vegetables than menu B (menu A; 120+/-58 g, menu B; 72+/-71 g). The contents of nitrite in menu A and B were 1.2+/-0.3 mg (0.7-1.8 mg) and 2.8+/-0.9 mg (1.3-4.6 mg), respectively, and 6 samples in menu B exceeded the ADI. Intake of 350 g of vegetables or more in a day may require careful consideration of selection, frequency of use and cooking method, especially for vegetables with high nitrate content. A questionnaire to female students showed that 80% or more of students recognized that vegetables containing high contents of nitrate, such as spinach and komatsuna, should be boiled before eating them.

Measurement of dietary choline-phospholipid content by a novel phospholipase D-triiodide method.

We developed a novel method that conveniently measures dietary choline-phospholipid content. Crude lipids extracted from dietary samples were reacted with phospholipase D from Streptomyces chromofuscus. The choline liberated from this reaction was then reacted with potassium triiodide, yielding choline periodide, which could be measured spectrophotometrically at 365 nm. This method proved to be more convenient than conventional assays, such as thin layer chromatography and high performance liquid chromatography. Our novel method is suitable for measuring many samples in single experiments.

[Nitrate and nitrite contents in vegetable juice, tea beverage and mineral water on the market].

The contents of nitrate and nitrite in vegetable juice (n = 63), tea beverage (n = 12) and mineral water (n = 15) were measured. The mean contents of nitrate were 0.73 +/- 14.57 mg/100 g, 0.61 +/- 1.12 mg/100 g and 0.25 +/- 0.33 mg/100 g as NO3-, respectively. The contents of the nitrite were 0.03 +/- 0.05 mg/100 g, 0.02 +/- 0.01 mg/100 g and 0.001 +/- 0.001 mg/100 g as NO2-, respectively. The content of nitrate is high in some vegetable juices, and warnings may be necessary for people who drink them frequently.

Cholesterol intake is associated with lecithin intake in Japanese people.

Many dietary recommendations for the prevention of heart disease and hyperlipidemia include restriction of cholesterol intake. However, limiting cholesterol intake might also affect the intake of other nutrients. The daily intakes of cholesterol, lecithin, total fatty acids, and SFAs by 388 Japanese subjects (ages 6-59 y) were analyzed directly using the duplicate portion sampling technique. Intakes were 266.1 +/- 146.5 mg/d, 1.6 +/- 0.9 g/d, 39.3 +/- 16.8 g/d, and 12.8 +/- 6.9 g/d, respectively. There was a strong positive correlation between cholesterol and lecithin intakes (r = 0.864, P < 0.001), and when food intake was adjusted to 1 kg/d, the correlation remained high (r = 0.881, P < 0.001). In contrast, the correlation between total fatty acid and lecithin intakes was lower (r = 0.423, P < 0.001), and when food intake was adjusted to 1 kg/d, the correlation coefficient remained stable (r = 0.448, P < 0.001). These results strongly indicate that limiting cholesterol intake decreases lecithin intake. Lecithin intake can be estimated from the following regression equation: lecithin intake (g/d) = 0.005 x cholesterol intake (mg/d) + 0.16 (R2= 0.747, P < 0.001). Furthermore, the intake of choline derived from lecithin can be estimated by the following equation: choline (mg/d) = 0.724 x cholesterol (mg/d) + 21.5.

Effects of soybean beta-conglycinin on body fat ratio and serum lipid levels in healthy volunteers of female university students.

The changes in body fat ratio and serum lipids induced by the ingestion of beta-conglycinin were examined in 41 healthy female university student volunteers. The trend of change in body fat ratio following the ingestion of beta-conglycinin differed between students with a baseline body fat ratio over 25% and those less than 25%. In the former group, the ingestion of beta-conglycinin suppressed the increase in body fat ratio. Moreover the six subjects who had a high total cholesterol level (5.72 mmol/L or higher) tended to have reduced levels of serum triglyceride, free fatty acid, total cholesterol and lipoprotein (a) after the ingestion of beta-conglycinin, although those levels did not change significantly. The number of subjects was only six, therefore it was inferred that significant changes were not observed. Thus, ingestion of soybean beta-conglycinin suppressed the increase in body fat ratio in individuals with a high baseline body fat ratio and reduced relatively high serum levels of lipids. Those results suggest that if soybean beta-conglycinin is ingested continuously (5 g daily), it will be effective in keeping body fat ratio and serum lipid levels normal and eliminating excessive lipids from the body.

[Survey of the daily intake of nitrate and nitrite in school children by the duplicate portion method].

The daily intake of nitrate and nitrite in school children (n = 100) in Hiroshima Prefecture was estimated directly by the duplicate portion method. The daily intake of nitrate was 68.42 +/- 77.49 mg. The daily intake of nitrate/kg body weight was 2.06 +/- 2.24 mg, which is about 56% of the acceptable daily intake (ADI). The daily intake of nitrite was 0.953 +/- 0.869 mg. The daily intake of nitrite/kg body weight was 0.027 +/- 0.021 mg, which is about 45% of the ADI. The daily intake of nitrite/kg body weight was significantly different between the obese group and the non-obese group in boys (p < 0.05, Mann-Whitney U-test). The rates of children whose daily intakes of nitrate and nitrite were above the ADI were 16% and 7%, respectively.