Trans fatty acids (TFAs) are positional isomers of cis fatty acids. TFAs are mainly produced by partial hydrogenation of unsaturated fatty acids and widely found in a variety of foods, including margarine, shortening and frying oil. A small amount of TFAs is also found in ruminant fats and milk. The amount of TFA intake in Western Europe and North America probably ranges from 5 to 15g/day. Epidemiological studies have shown that an excessive consumption of TFAs raised the LDL-cholesterol level and lowered HDL-cholesterol in humans. A high intake of TFAs is therefore thought to be a risk factor of coronary heart disease. On the basis of scientific evidence, the U. S. FDA required labeling of the TFA content for conventional food and dietary supplements on January 1, 2006. TFAs are also restricted their uses in the EU. The TFA intake in Japan is estimated to be approximately 1.6g/day, this amount being markedly lower than that in western countries. Although the low TFA intake in Japan is not thought to be an important issue at present, we should pay attention to an excessive intake of TFAs in the future.
A questionnaire survey was conducted on those persons responsible for cooking to identify their awareness of the importance of the dietary life and lifestyle of elementary school children. The 247 subjects were all guardians of children attending elementary schools in a town in Hiroshima Prefecture, and 190 of these subjects were selected for a multiple regression analysis as being responsible for cooking the children's meals. The greater the dietary awareness of those responsible for cooking, the higher was the intake frequency of seaweed, small fish, root crops, and potatoes by the elementary school children. A more positive attitude toward food education in those cooking meals resulted in a more frequent intake of seaweed, small fish, soy beans, and soy bean products by the elementary school children, with no problems presented for such dietary constituents. Greater health consciousness in those cooking meals resulted in less desire for carbonated drinks, juice and snacks, and fewer problems with the elementary school children in waking up in the morning. These results demonstrate that the dietary awareness of those persons responsible for cooking influenced the dietary life and lifestyle of the elementary school children, and implies the need to improve the level of dietary awareness of those cooking meals.
The validity was assessed of the “Dietary Record by Cooked Dishes” (DRcd) method, a newly developed and simplified self-reported dietary record, together with a smaller sample size for constructing the dish-based component table. Scale-based one-day dietary records were compiled by 224 subjects from 2000 to 2002, the amounts of nutrients in each dish were calculated by using the 5th standard food composition table, and the results were used to construct the dish-based component table (DRcd224). Databases for DRcd125 and DRcd75, which respectively used 125 and 75 samples from the 224 subjects randomly selected 5 times from each, were next constructed in the same way. A one-day dietary survey using the DRcd databases was finally conducted on 106 subjects in 2003 and 2004 to assess the validity of the method. The median values of Pearson's correlation coefficients for the intake of energy, of 29 nutrients, and of 21 food groups between DR and DRcd224 were 0.808 and 0.921, respectively. The correlation coefficients of the minimum and maximum values of the 5-times calculation for DRcd125 were 0.701 and 0.754 (nutrients), and 0.685 and 0.796 (food groups), and for DRcd75 were 0.686 and 0.724, and 0.662 and 0.726, respectively. The ratio of the energy intake assessed by DRcd224 to that by DR was 92.2%, and the ratios of the median values for nutrients assessed by DRcd125 and DRcd22275 to DRcd224 were 97.5-102.8% and 99.2-104.8%, respectively. Although the correlation coefficients between DR and DRcd224 were higher than those for DRcd125 and DRcd75, there was little effect from this difference in estimating the dietary intake. A sample size of 75 would therefore be practical for constructing DRcd in field research.
The nutritional status of zinc in the elderly and the effect of zinc supplementation on this nutritional status were studied. The relationship was examined between the serum zinc concentration and food intake of healthy elderly persons (n=11; average age, 80; Female/Male=6/5) admitted to a health facility for six months, to whom an oral zinc supplement had been administered for the last three months (8mg/day for one month, and 16mg/day for the following two months). The daily oral intake of zinc was lower than the dietary reference intake (RDA: recommended dietary allowance) of zinc for the first three months. Daily oral zinc supplementation during the last three months induced no significant increase in the serum zinc concentration, although the zinc intake exceeded the dietary reference intake (RDA). A positive correlation was apparent between the serum zinc concentration and the daily intake of energy or protein, particularly during the last three months, and also between the same zinc concentration data and the serum albumin or iron concentration. This correlation suggests that, in ensuring that the elderly maintain a suitable serum zinc concentration, it is important to consider the total nutritional status, including the intake of energy and proteins and the albumin levels, when providing dietary zinc supplementation.