Assessment of vegetable, fruit, and antioxidant vitamin intake in cancer epidemiology

Inverse associations are consistently observed in epidemiological studies on the relations between the consumption of vegetables and fruits and different types of cancer. The strength of these associations is, however, unknown amongst others because of measurement error in data on vegetable and fruit intake. The antioxidant (pro)vitamins β-carotene, vitamin C, and vitamin E, are three of many substances in vegetables and fruits which may be responsible for the anticarcinogenic effect. This thesis is focused on the problem of intake assessment of vegetables, fruits, and antioxidant (pro)vitamins.In the first part of the thesis, two studies on the relationships between the consumption of vegetables, fruits, and antioxidant (pro)vitamins and the occurrence of cancer are described. In the Seven Countries Study intake of vitamin C was inversely related to stomach cancer mortality at ecological level. Subjects with low intakes of vegetables, fruits, and β-carotene that were stable over time experienced more than two-fold increased risks of lung cancer in the Zutphen Study than subjects with high stable intakes. A lack of information on the extent of measurement error in the dietary data in both studies hampered the correct interpretation of the results.The second part of the thesis includes several studies on the estimation of measurement error in data on vegetable, fruit, and antioxidant (pro)vitamin intake and biochemical markers. In a study on the effects of frozen storage at -20°C it was shown that vitamin E concentrations in EDTA-plasma decreased dramatically between 6 and 12 months, whereas for β-carotene this took place after 1 year. The use of such plasma in nested case-control or case-cohort studies would result in highly attenuated odds ratios for β-carotene and vitamin E.Reproducibility and relative validity for food group and nutrient intake assessed with an extensive semi-quantitative food frequency questionnaire was also investigated. The questionnaire seemed adequate for ranking subjects according to intake of most nutrients and food groups including fruits, but it did not yield such good results for vegetables, β-carotene, vitamin C for men, and vitamin E for women. The observed correlation coefficients between questionnaire and repeated 24-h recall data may be either over- or underestimates of the true validity coefficients, because of unknown error structure in both types of data. Validity coefficients estimated by a triangular comparison between questionnaire, 24-h recall, and biomarker measurements will probably be overestimates of true validity coefficients.From these studies it is concluded that measurement error in assessing vegetable, fruit, and antioxidant (pro)vitamin intake may be large, which is a handicap for epidemiological studies. Further progress lies in improvement of dietary assessment methods, and probably even more in understanding error structures and the development of analytical methods to recognize and cope with those structures

O SUS sobrevive aos tempos de pandemia?

N/AN/

Evaluation of the Dutch general exemption level for voluntary fortification with folic acid

Introduction: Fortification with folic acid was prohibited in the Netherlands. Since 2007, a general exemption is given to fortify with folic acid up until a maximum level of 100 µg/100 kcal. This maximum level was based on a calculation model and data of adults only. The model requires parameters on intake (diet, supplements, energy) and on the proportion of energy that may be fortified. This study aimed to evaluate the model parameters considering the changing fortification market. In addition, the risk of young children exceeding the UL for folic acid was studied. Methods: Folic acid fortified foods present on the Dutch market were identified in product databases and by a supermarket inventory. Together with data of the Dutch National Consumption Survey-Young Children (2005/2006) these inventory results were used to re-estimate the model parameters. Habitual folic acid intake of young children was estimated and compared to the UL for several realistic fortification scenarios. Results: Folic acid fortified foods were identified in seven different food groups. In up to 10% of the population, the proportion of energy intake of folic acid fortified foods exceeded 10% – the original model parameter. The folic acid intake from food supplements was about 100 µg/day, which is lower than the intake assumed as the original model parameter (300 µg). In the scenarios representing the current market situation, a small proportion (<5%) of the children exceeded the UL. Conclusion: The maximum fortification level of 100 µg/100 kcal is sufficiently protective for children in the current market situation. In the precautionary model to estimate the maximum fortification levels, subjects with high intakes of folic acid from food and supplements, and high energy intakes are protected from too high folic acid intakes. Combinations of high intakes are low in this population. The maximum levels should be monitored and revised with increasing fortification and supplementation practices

Effectiveness of customary use of phytosterol/-stanol enriched margarines on blood cholesterol lowering.

Postlaunch monitoring of functional foods can encompass monitoring of effectiveness under conditions of customary use. To this end, the effectiveness of phytosterol/-stanol enriched margarine consumption in free-living conditions was investigated with data from the Dutch "Doetinchem cohort study". In total, 4,505 subjects (aged 26-70 years) were examined in 1994-1998 and re-examined during 1999-2003. A general and a food frequency questionnaire and non-fasting blood samples for total and HDL cholesterol determination were obtained. Subjects were stratified into phytosterol/-stanol enriched margarine users (n = 84) and non-users (n = 4,421) based on the re-examination data, as these margarines were available on the Dutch market from 1999 onwards. Mean spontaneous daily use (g +/- SD) of phytosterol-containing margarine (n = 71) was 15 +/- 8 and of phytostanol-containing margarine (n = 13) 9+/-6. After five years, total blood cholesterol had increased with 0.26 mmol/l in non-users while it had not significantly changed in users. The difference in total blood cholesterol change in users versus non-users was -0.30 mmol/l (p < 0.001). The beneficial effect of the phytosterol/-stanol enriched margarine, used under customary conditions can be characterized as a stabilization of cholesterol levels. This is the first report finding a modest beneficial effect on blood cholesterol level under customary conditions thereby partly confirming findings from clinical trials

Raw and Processed Fruit and Vegetable Consumption and 10-Year Coronary Heart Disease Incidence in a Population-Based Cohort Study in the Netherlands

Background: Prospective cohort studies have shown that high fruit and vegetable consumption is inversely associated with coronary heart disease (CHD). Whether food processing affects this association is unknown. Therefore, we quantified the association of fruit and vegetable consumption with 10-year CHD incidence in a population-based study in the Netherlands and the effect of processing on these associations. Methods: Prospective population-based cohort study, including 20,069 men and women aged 20 to 65 years, enrolled between 1993 and 1997 and free of cardiovascular disease at baseline. Diet was assessed using a validated 178-item food frequency questionnaire. Hazard ratios (HR) were calculated for CHD incidence using multivariable Cox proportional hazards models. Results: During a mean follow-up time of 10.5y, 245 incident cases of CHD were documented, which comprised 211 nonfatal acute myocardial infarctions and 34 fatal CHD events. The risk of CHD incidence was 34 % lower for participants with a high intake of total fruit and vegetables (.475 g/d; HR: 0.66; 95 % CI: 0.45–0.99) compared to participants with a low total fruit and vegetable consumption (#241 g/d). Intake of raw fruit and vegetables (.262 g/d vs #92 g/d; HR: 0.70; 95 % CI: 0.47–1.04) as well as processed fruit and vegetables (.234 g/d vs #113 g/d; HR: 0.79; 95 % CI: 0.54–1.16) were inversely related with CHD incidence

Validation of a food quantification picture book targeting children of 0–10 years of age for pan-European and national dietary surveys

The aim of the present study was to validate thirty-eight picture series of six pictures each developed within the PANCAKE (Pilot study forthe Assessment of Nutrient intake and food Consumption Among Kids in Europe) project for portion size estimation of foods consumed byinfants, toddlers and children for future pan-European and national dietary surveys. Identical validation sessions were conducted in threeEuropean countries. In each country, forty-five foods were evaluated; thirty-eight foods were the same as the depicted foods, and sevenfoods were different, but meant to be quantified by the use of one of the thirty-eight picture series. Each single picture within a pictureseries was evaluated six times by means of predefined portions. Therefore, thirty-six pre-weighed portions of each food were evaluatedby convenience samples of parents having children aged from 3 months to 10 years. The percentages of participants choosing the correctpicture, the picture adjacent to the correct picture or a distant picture were calculated, and the performance of individual pictures withinthe series was assessed. For twenty foods, the picture series performed acceptably (mean difference between the estimated portion numberand the served portion number less than 0·4 (SD ,1·1)). In addition, twelve foods were rated acceptable after adjustment for density differences.Some other series became acceptable after analyses at the country level. In conclusion, all picture series were acceptable forinclusion in the PANCAKE picture book. However, the picture series of baby food, salads and cakes either can only be used for foodsthat are very similar to those depicted or need to be substituted by another quantification tool.</p

Near normal HbA1c with stable glucose homeostasis: the ultimate target/aim of diabetes therapy

Background: The long-term longitudinal evidence for a relation between coffee intake and hypertension is relatively scarce. Objective: The objective was to assess whether coffee intake is associated with the incidence of hypertension. Design: This study was conducted on a cohort of 2985 men and 3383 women who had a baseline visit and follow-up visits after 6 and 11 y. Baseline coffee intake was ascertained with questionnaires and categorized into 0, &gt; 0-3, &gt; 3-6, and &gt; 6 cups/d. Hypertension was defined as a mean systolic blood pressure (SBP) &gt;= 140 mm Hg over both follow-up measurements, a mean diastolic blood pressure (DBP) &gt;= 90 mm Hg over both follow-up measurements, or the use of antihypertensive medication at any follow-up measurement. Results: Coffee abstainers at baseline had a lower risk of hypertension than did those with a coffee intake of &gt; 0-3 cups/d [odds ratio (OR): 0.54; 95% CI: 0.31, 0.92]. Women who drank &gt; 6 cups/d had a lower risk than did women who drank &gt; 0-3 cups/d (OR: 0.67; 95% CI: 0.46, 0.98). Subjects aged &gt;= 39 y at baseline had 0.35 mm Hg (95% CI: -0.59, -0.11 mm Hg) lower SBP per cup intake/d and 0.11 mm Hg lower DBP (95% CI: -0.26, 0.03 mm Hg) than did those aged &lt;39 y at baseline, although the difference in DBP was not statistically significant. Conclusions: Coffee abstinence is associated with a lower hypertension risk than is low coffee consumption. An inverse U-shaped relation between coffee intake and risk of hypertension was observed in the women