Seasonality of food groups and total energy intake: a systematic review and meta-analysis.

BACKGROUND/OBJECTIVES: The aim of this systematic review and meta-analysis was to assess the effect of season on food intake from selected food groups and on energy intake in adults. SUBJECTS/METHODS: The search process was based on selecting publications listed in the following: Medline, Scopus, Web of Science, Embase and Agris. Food frequency questionnaires, 24-h dietary recalls and food records as methods for assessment of dietary intake were used to assess changes in the consumption of 11 food groups and of energy intake across seasons. A meta-analysis was performed. RESULTS: Twenty-six studies were included. Articles were divided into those reporting data on four seasons (winter, spring, summer and autumn) or on two seasons (pre-and post-harvest). Four of the studies could be utilized for meta-analysis describing changes in food consumption across four season scheme: from winter to spring fruits decreased, whereas vegetables, eggs and alcoholic beverages increased; from spring to summer vegetable consumption further increased and cereals decreased; from summer to autumn fruits and cereals increased and vegetables, meat, eggs and alcoholic beverages decreased; from autumn to winter cereals decreased. A significant association was also found between energy intake and season, for 13 studies reporting energy intake across four seasons (favors winter) and for eight studies across pre- and post-harvest seasons (favors post-harvest). CONCLUSIONS: The winter or the post-harvest season is associated with increased energy intake. The intake of fruits, vegetables, eggs, meat, cereals and alcoholic beverages is following a seasonal consumption pattern and at least for these foods season is determinant of intake.

Development and evaluation of a short 24-h food list as part of a blended dietary assessment strategy in large-scale cohort studies.

BACKGROUND/OBJECTIVES: The validity of dietary assessment in large-scale cohort studies has been questioned. Combining data sources for the estimation of usual intake in a blended approach may enhance the validity of dietary measurement. Our objective was to develop a web-based 24-h food list for Germany to identify foods consumed during the previous 24 h and to evaluate the performance of the new questionnaire in a feasibility study. SUBJECTS/METHODS: Available data from the German National Nutrition Survey II were used to develop a finite list of food items. A total of 508 individuals were invited to fill in the 24-h food list via the Internet up to three times during a 3-6-month time period. In addition, participants were asked to evaluate the questionnaire using a brief online evaluation form. RESULTS: In total, 246 food items were identified for the 24-h food list, reflecting >75% variation in intake of 27 nutrients and four major food groups. Among the individuals invited, 64% participated in the feasibility study. Of these, 100%, 85% and 68% of participants completed the 24-h food list one, two or three times, respectively. The average time needed to complete the questionnaire was 9 min, and its acceptability by participants was rated as high. CONCLUSIONS: The 24-h food list represents a promising new dietary assessment tool that can be used as part of a blended approach combining multiple data sources for valid estimation of usual dietary intake in large-scale cohort studies.

Dietary glycemic index, glycemic load, insulin index, fiber and whole-grain intake in relation to risk of prostate cancer.

OBJECTIVE: Insulin may play a role in prostate cancer tumorigenesis. Postprandial blood glucose and insulin responses of foods depend importantly on the carbohydrate quality and quantity, represented by glycemic index (GI), glycemic load (GL), fiber and whole-grain content, but are also influenced by intake of protein and other characteristics. The recently developed insulin index (II) quantifies the postprandial insulin secretion, also taking into account these additional characteristics. METHODS: We investigated the association between dietary GI, GL, II, fiber, and whole grains and risk of total prostate cancer (n = 5,112) and subgroups of prostate cancer as defined by stage or grade in 49,934 male participants of the Health Professionals Follow-up Study. Multivariate adjusted hazard ratios (HR) and 95% confidence intervals (95% CI) were estimated using Cox proportional hazards regression. RESULTS: Dietary GI, GL, II, or fiber was not associated with risk of total or subgroups of prostate cancer. We observed a positive association between dietary intake of whole grains and total prostate cancer (HR highest versus lowest quintile 1.13, 95% CI 1.03-1.24), which was attenuated after restriction to PSA-screened participants (HR 1.03, 95% CI 0.91-1.17). CONCLUSIONS: These results suggest that long-term exposure to a diet with a high insulin response does not affect prostate cancer incidence.

Differently complex oligosaccharides can be easily identified by matrix-assisted laser desorption and ionization time-of-flight mass spectrometry directly from a standard thin-layer chromatography plate.

Thin-layer chromatography (TLC) is a simple, fast and inexpensive separation method. Unambiguous identification of the TLC spots is, however, often a problem. Here we show for the first time that oligosaccharides (derived from dextran, alginate, hyaluronan and chondroitin sulfate) can be characterized by matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) directly on a TLC plate. The applied oligosaccharides were either commercially available or obtained from the polysaccharides by HCl-induced hydrolysis. Normal phase TLC was followed by MALDI-TOF MS subsequent to matrix deposition. It will be shown that high quality mass spectra can be obtained that enable unequivocal assignments. It will also be shown that the high content of formic acid in the solvent system does not confer major problems but is responsible for the partial formylation of the analyte and minor N-acetyl loss from hyaluronan and chondroitin sulfate.

Use of dietary supplements in the European Prospective Investigation into Cancer and Nutrition calibration study.

BACKGROUND: Dietary supplement use is increasing, but there are few comparable data on supplement intakes and how they affect the nutrition and health of European consumers. The aim of this study was to describe the use of dietary supplements in subsamples of the 10 countries participating in the European Prospective Investigation into Cancer and Nutrition (EPIC). METHODS: Specific questions on dietary supplement use were asked as a part of single 24-h recalls performed on 36,034 men and women aged 35-74 years from 1995 to 2000. RESULTS: Between countries, the mean percentage of dietary supplement use varied almost 10-fold among women and even more among men. There was a clear north-south gradient in use, with a higher consumption in northern countries. The lowest crude mean percentage of use was found in Greece (2.0% among men, 6.7% among women), and the highest was in Denmark (51.0% among men, 65.8% among women). Use was higher in women than in men. Vitamins, minerals or combinations of them were the predominant types of supplements reported, but there were striking differences between countries. CONCLUSIONS: This study indicates that there are wide variations in supplement use in Europe, which may affect individual and population nutrient intakes. The results underline the need to monitor consumption of dietary supplements in Europe, as well as to evaluate the risks and benefits.