Effects of dietary fat and a vegetable-fruit mixture on the development of intestinal neoplasia in the ApcMin mouse

The variation in colorectal cancer (CRC) incidence worldwide strongly suggests a role for dietary influences. Based on epidemiological data, protective effects of vegetables and fruit intake on CRC are widely claimed, while other data indicate a possible increased CRC risk from (higher) dietary fat intake. Therefore, we have investigated single and interactive effects of dietary fat and a vegetable-fruit mixture (VFM) in the ApcMin mouse, a mouse model for multiple intestinal neoplasia. In this study, four different diets (A-D) were compared, which were either low in fat (20% energy diets A/B) or high in fat (40% energy diets C/D). In addition, 19.5% (wt/wt) of the carbohydrates in diets B and D were replaced by a freeze-dried VFM. The diets were balanced so that they only differed among each other in fat/carbohydrate content and the presence of specific plant-constituents. Because the initiation of intestinal tumors in ApcMin mice occurs relatively early in life, exposure to the diets was started in utero. Without the addition of VFM, mice maintained at a high-fat diet did not develop significantly higher numbers of small or large intestinal adenomas than mice maintained at a low-fat diet. VFM added to a low-fat diet significantly lowered multiplicity of small intestinal polyps (from 16.2 to 10.2/mouse, 15 animals/group), but not of colon tumors in male ApcMin mice only. Strikingly, addition of VFM to female mice maintained on a low-fat diet and to both sexes maintained on a high-fat diet significantly enhanced intestinal polyp multiplicity (from 16.5 to 26.7 polyps/mouse). In conclusion, our results indicate that neither a lower fat intake nor consumption of VFM included in a high-fat diet decreases the development of polyps in mice genetically predisposed to intestinal tumor development.      

Trends in cervical squamous cell carcinoma incidence in 13 European countries: changing risk and the effects of screening.

Despite there being sufficient evidence for the effectiveness of screening by cytology in preventing cancer of the cervix uteri, screening policies vary widely among European countries, and incidence is increasing in younger women. This study analyzes trends in squamous cell carcinoma (SCC) of the cervix uteri in 13 European countries to evaluate effectiveness of screening against a background of changing risk. Age-period-cohort models were fitted and period and cohort effects were estimated; these were considered as primarily indicative of screening interventions and changing etiology, respectively. A unique set of estimates was derived by fixing age slopes to one of several plausible age curves under the assumption that the relation between age and cervical cancer incidence is biologically determined. There were period-specific declines in cervical SCC in several countries, with the largest decreases seen in northern Europe. A pattern emerged across Europe of escalating risk in successive generations born after 1930. In the western European countries, a decrease followed by a stabilization of risk by cohort was accompanied by period-specific declines. In southern Europe, stable period, but increasing cohort trends, were observed. Substantial changes have occurred in cervical SCC incidence in Europe and well-organized screening programs have been highly effective in reducing the incidence of cervical SCC. Screening and changing sexual mores largely explain the changing period- and cohort-specific patterns, respectively. The increasing risk in recent cohorts is of obvious concern particularly in countries where no screening programs are in place. Further investigation of the effectiveness of opportunistic screening is warranted as is the observation of differing risk patterns in young cohorts in countries with relatively similar societal structures.     

Day-to-Day Variation in Food Intake and Energy Expenditure in Healthy Women: The Dietitian II Study

Because day-to-day food intake varies, we tested the hypothesis that ad libitum food intake and energy expenditure show corrective responses over periods of 1 to 10 days in healthy young women. Food intake and accelerometry measurements were collected daily for 17 days in 15 young women. Total daily energy expenditure (TDEE) using doubly labeled water was also measured. The daily deviations in macronutrient and energy intake and energy expenditure from the average values were compared with the deviations observed over succeeding intervals to estimate the corrective responses. The intraindividual coefficients of variation for energy intake averaged ±25%, ranging from 16% to 34%. TDEE had a coefficient of variation of 8.3%, and accelerometry had a coefficient of variation of 8.4% (range=4.6% to 16.4%). Energy expenditure by accelerometry (2,087±191 kcal/day) was not significantly different from TDEE (2,128±177 kcal/day), but reported daily energy intake was 20.4% lower (1,693±276 kcal/day). There were significant corrective responses in energy from fat and total energy intake. This occurred from Days 3 to 6, with a peak at Day 5 that disappeared when data were randomized within each subject. Human beings show corrective responses to deviations from average energy and macronutrient intakes with a lag time of 3 to 6 days, but not 1 to 2 days. These corrective responses are likely to play a role in bringing about weight stability.