Development and validation of a photographic atlas of food portions for accurate quantification of dietary intakes in China.

BACKGROUND: Accurate estimation of food portion sizes remains an important challenge in dietary data collection. The present study aimed to develop a food atlas with adequate visual reference to improve the accuracy of dietary surveys in China. METHODS: A food atlas for dietary surveys in China was developed using three visual reference systems, namely, regularly placed food portions, the two-dimensional background coordinates and common objects known in daily life. The atlas was validated by estimating a meal before and after using the food atlas, and differences in weight estimation were compared using a paired t-test. In total, 50 college students participated in the study. RESULTS: After determination of food varieties; design of the food display; purchase, processing, cooking and weighing of food; photographing food; post-image processing and data processing, a total of 799 pictures of 303 types of food and two types of tableware were produced. The mean value of food weight estimated with the atlas was closer to the actual weight, and the variation range of these values was smaller and more stable than that estimated without the atlas. The differences estimated before and after using the atlas for all foods were significant (P < 0.05). Comparing the differences in weight before using the atlas, the error ranges of food samples were reduced. CONCLUSIONS: A food atlas has been developed for a retrospective dietary survey in China, which can be used to enable a better understanding of nutritional adequacy in the Chinese population.

[Effects of high-sucrose/high-fat diet feeding time on establishment of a mouse model of gestational diabetes mellitus].

OBJECTIVE: The present study focuses on the effects of different highsucrose/high-fat diet feeding time on body weight, glucose and lipid metabolism parameters and pathological changes of pancreas and liver in pregnant mice. METHODS: Female C57 BL/6 J mice were divided into three groups randomly: normal control group( C) and two different high-sucrose/high-fat diet feeding time groups( H1 and H2). Body weight, food and energy intakes and blood glucose were measured at multiple time points before and during pregnancy. At the 17 thday of pregnancy, the mice were killed after blood collection. The parameters about glucose and lipid metabolism and serum insulin level were studied. Meanwhile, pancreas and liver tissues were collected for pathological examination. RESULTS: The body weight of group H1 and group H2 were respectivelyhigher than that of group C at multiple time points before pregnancy. With the increase of high-sucrose/high-fat diet feeding time, the tendency of body weight during pregnancy was showed as: group H2 > group H1 > group C. At the 10 thday of pregnancy, the tendency of blood glucose level was showed as: group H2 > group H1 > group C. At the 17 thday of pregnancy, there was no significant difference in blood glucose and insulin levels among the three groups. However, with the increase of high-sucrose/high-fat diet feeding time, the score of ß-cell function had a decreasing trend. Furthermore, the LDL-C level in group H1 and group H2 was significantly higher than that in group C respectively. Histopathological observations showed that the morphological structures of pancreas and liver in group C were normal. However, hypertrophy of pancreatic islets and fatty deposition of liver were existed in the other two groups, and the pathological changes in group H2 were more serious than those in group H1. CONCLUSION: By controlling the feeding time of high-sucrose/high-fat diet, the progressive development of gestational diabetes mellitus in C57 BL/6 J mice could be observed roughly.