Relative bioavailability of the flavonoids quercetin, hesperetin and naringenin given simultaneously through diet.

The bioavailability and urinary excretion of three dietary flavonoids, quercetin, hesperetin and naringenin, were investigated. Ten healthy men were asked to consume a 'juice mix' containing equal amounts of the three flavonoids, and their urine and plasma samples were collected. The resulting mean plasma area under the curve (AUC)(0-48 h) and C(max) values for quercetin and hesperetin were similar, whereas the AUC(0-48 h) of naringenin and, thus, the relative bioavailability were higher after consumption of the same dose. The study consolidates a significantly lower urinary excretion of quercetin (1.5+/-1%) compared with hesperetin (14.2+/-9.1%) and naringenin (22.6+/-11.5%) and shows that this is not due to a lower bioavailability of quercetin, but rather reflects different clearance mechanisms.

Validity of a questionnaire to assess fruit and vegetable intake in adults.

OBJECTIVE: To validate a method for assessing fruit and vegetable intake among adults in a population of low intake. The method assesses mean intake and ranks individuals by their usual intake. DESIGN: A precoded fruit and vegetable Questionnaire included a 24-h recall and a food frequency. The participants filled in the Questionnaire, a week later they started a 7-day food record, 1-day weighed record and 6 days using household measures. SUBJECTS: Following advertisements 40 participants were recruited, 36 returned food records(mean age=37 years). RESULTS: No difference was observed between the average intake yielded by the 24-h recall and that from the 1-day weighed food record of fruits or vegetables. Correlation coefficients between results from the food frequency questionnaire and the 7-day food records were 0.45 (P=0.007) for vegetables, 0.63 (P<0.001) for fruits and 0.73 (P<0.001) for fruits and vegetables combined. Cross-classification into quartiles showed that the proportion of participants in the same or the adjacent quartile of the intake distribution were 94% for fruit intake and 80% for vegetable intake. Registered intake of fruits and vegetables was higher the first 4 days of the record than the last 3 days (P=0.002). The 4-day food record correlated with the food frequency questionnaire in similar manner as the 7-day record. CONCLUSION: The present study indicates that the precoded 24-h recall may be valuable tool for measuring average intake of fruits and vegetables among adults in a population of low intake. Moreover, the food frequency questionnaire was valid for ranking individuals according to their usual intake. A 4-day food record might be sufficient when validating food frequency questionnaires for fruits and vegetables.

Sociodemographic differences in dietary habits described by food frequency questions--results from Denmark.

OBJECTIVES: To investigate whether a modest number of food frequency questions are sufficient to describe sociodemographic differences in dietary habits, and to identify sociodemographic characteristics of subjects adhering to food-based dietary guidelines operationalised in a "healthy-diet index". DESIGN: Cross-sectional population survey. SUBJECTS: A total of 480 men, 515 women, aged 15-90 y. Random sample of private telephone numbers drawn from regional telephone records, geographically stratified. Participation rate 62%. METHODS: Computer-assisted telephone interviews, including six food frequency questions, a question on type of fat spreads used on bread, questions on seven sociodemographic variables. RESULTS: The summary of the healthy-diet index showed that the subjects who adhered to food-based dietary guidelines (top quintile) compared to those who did not (bottom quintile) were most often women (odds ratio (OR)=6.07; confidence interval (CI): 3.91-9.43, women vs men), of older age (OR=9.72; CI: 3.02-31.31, old age vs young), highly educated (OR=3.69; CI: 1.53-8.92, high education vs low) and living in multiperson households including children (OR=4.66; CI: 2.47-8.80, multiperson household vs single household). The results also showed that gender difference in dietary habits is associated with other sociodemographic variables. CONCLUSIONS: The selected food frequency questions proved sufficient to describe sociodemographic differences in dietary habits, and this method may be a valuable supplement to traditional quantitative dietary surveys in monitoring sociodemographic changes in eating patterns. The results also underline the influence of sociodemographic status on dietary habits. SPONSORSHIP: The Danish Nutrition Council funded the study.

Green tea extract only affects markers of oxidative status postprandially: lasting antioxidant effect of flavonoid-free diet.

Epidemiological studies suggest that foods rich in flavonoids might reduce the risk of cardiovascular disease and cancer. The objective of the present study was to investigate the effect of green tea extract (GTE) used as a food antioxidant on markers of oxidative status after dietary depletion of flavonoids and catechins. The study was designed as a 2 x 3 weeks blinded human cross-over intervention study (eight smokers, eight non-smokers) with GTE corresponding to a daily intake of 18.6 mg catechins/d. The GTE was incorporated into meat patties and consumed with a strictly controlled diet otherwise low in flavonoids. GTE intervention increased plasma antioxidant capacity from 1.35 to 1.56 (P<0.02) in postprandially collected plasma, most prominently in smokers. The intervention did not significantly affect markers in fasting blood samples, including plasma or haemoglobin protein oxidation, plasma oxidation lagtime, or activities of the erythrocyte superoxide dismutase, glutathione peroxidase, glutathione reductase and catalase. Neither were fasting plasma triacylglycerol, cholesterol, alpha-tocopherol, retinol, beta-carotene, or ascorbic acid affected by intervention. Urinary 8-oxo-deoxyguanosine excretion was also unaffected. Catechins from the extract were excreted into urine with a half-life of less than 2 h in accordance with the short-term effects on plasma antioxidant capacity. Since no long-term effects of GTE were observed, the study essentially served as a fruit and vegetables depletion study. The overall effect of the 10-week period without dietary fruits and vegetables was a decrease in oxidative damage to DNA, blood proteins, and plasma lipids, concomitantly with marked changes in antioxidative defence.

Monitoring of dietary changes by telephone interviews: results from Denmark.

OBJECTIVES: To monitor trends in Danish food habits with respect to selected key elements, from 1995 to 1998, and to evaluate the appropriateness of the method developed for that purpose. DESIGN AND METHOD: Two cross-sectional population surveys, in 1995 and 1998. Data collection by computer-assisted telephone interviews including 10 food-frequency questions, questions on type of fat used on sandwiches and drinking milk, and check questions on the previous day. Reproducibility was tested in a subgroup (n = 222) in the 1998 survey. SETTING: The Danish Nutrition Council initiated the survey. SUBJECTS: Men and women aged 15-90 years, 1007 in 1995 and 1024 in 1998. Samples of private telephone numbers were drawn from regional telephone registers, geographically stratified. Participation rates were 62%. RESULTS: Significant differences were observed between 1995 and 1998, some of these in accordance with dietary guidelines (decreased use of whole milk and fat spread on bread, increased use of skimmed milk, salad vegetables, rice/pasta and fish). Other changes were opposite to dietary guidelines (increased use of soft butter, decreased use of soft margarine and low-fat spreads, potatoes, and fresh fruit). Differences in average consumption frequency amounted to 4-13%. Several results were confirmed by comparison with other data, and the reproducibility of the method was acceptable. Data were suitable for analysis of food use patterns, a relevant approach when assessing food habits in a lifestyle context. CONCLUSIONS: The changes observed illustrate the dynamics of food habits and the need for frequent monitoring. This simple telephone method may be a valuable tool for that purpose, as a supplement to national dietary surveys, also in a public health context.

Por una política de nutrición en Europa en el siglo XXI: desarrollo de unas guías alimentarias basadas en el consumo de alimentos / Towards a nutrition policy in Europe for the XXI centruy: development of food-based dietary guidelines

No disponible

[Polyphenolic antioxidants in fruit juice. Urinary excretion and effects on biological markers for antioxidative status]. / Polyfenoliske antioxidanter i frugtjuice. Udskillelse i urin samt indflydelse på biomarkører for antioxidativ status.

This intervention study was designed as cross-over (four women, one man) with three doses of black currant/apple (1:1) juice (750, 1000, and 1500 mL) for one week corresponding to an intake of 4.8, 6.4, and 9.6 mg quercetin per day. Urinary excretion of quercetin increased significantly with dose and with time. The fraction excreted in urine was constant 0.29-0.47%. Plasma quercetin did not change with juice intervention. Plasma ascorbate increased during intervention due to ascorbate from the juice. Total plasma malondialdehyde decreased with time during 1500 mL juice intervention. Plasma protein 2-adipic semialdehyde residues, increased with time and dose, and glutathione peroxidase increased with juice dose, whereas other selected markers of oxidative status did not change. These effects might be related to several components of the juice and cannot be attributed solely to its quercetin content.

[Changes in food habits among the population from 1995 to 1998]. / Aendringer i befolkningens fødevareforbrug 1995-1998.

In order to survey trends in food habits the Danish Nutrition Council initiated two food frequency surveys, comprising ten nutritionally important foods, in 1995 and in 1998. Participants were men and women, 15-90 yrs, from similar population samples (n = 1007 in 1995, 1024 in 1998). Participation rate was 62% in 1995 and 63% in 1998. Data were collected by telephone interview. For six of the ten foods significant changes in consumption frequencies were observed: salad/raw vegetables, rice/pasta and fish were consumed more frequently in 1998, whereas consumption of meat, potatoes and fresh fruit had become less frequent. Average frequencies differed by 4-13%. In 1998 low-fat milk had become more common, whereas whole milk was now less common. More subjects now skipped fat spreads on their bread, but more chose spreads containing butterfat. Some, but not all, of the observed changes point in the right direction compared to recommendations. The results demonstrate that food habits are currently in a dynamic process.

Effect of fruit juice intake on urinary quercetin excretion and biomarkers of antioxidative status.

BACKGROUND: Epidemiologic studies suggest that foods rich in flavonoids might reduce the risk of cardiovascular disease. OBJECTIVE: Our objective was to investigate the effect of intake of flavonoid-containing black currant and apple juice on urinary excretion of quercetin and on markers of oxidative status. DESIGN: This was a crossover study with 3 doses of juice (750, 1000, and 1500 mL) consumed for 1 wk by 4 women and 1 man corresponding to an intake of 4.8, 6.4, and 9.6 mg quercetin/d. RESULTS: Urinary excretion of quercetin increased significantly with dose and with time. The fraction excreted in urine was 0.29-0.47%. Plasma quercetin did not change with juice intervention. Plasma ascorbate increased during intervention because of the ascorbate in the juice. Total plasma malondialdehyde decreased with time during the 1500-mL juice intervention, indicating reduced lipid oxidation in plasma. Plasma 2-amino-adipic semialdehyde residues increased with time and dose, indicating a prooxidant effect of the juice, whereas erythrocyte 2-aminoadipic semialdehyde and gamma-glutamyl semialdehyde concentrations, Trolox-equivalent antioxidant capacity, and ferric reducing ability of plasma did not change. Glutathione peroxidase activity increased significantly with juice dose. CONCLUSIONS: Urinary excretion of quercetin seemed to be a small but constant function of quercetin intake. Short-term, high intake of black currant and apple juices had a prooxidant effect on plasma proteins and increased glutathione peroxidase activity, whereas lipid oxidation in plasma seemed to decrease. These effects might be related to several components of the juice and cannot be attributed solely to its quercetin content.

Dietary guidelines and patterns of intake in Denmark.

Food-based dietary guidelines in Denmark have usually been expressed in simple terms only and need to be elaborated. Quantitative recommendations on fruit and vegetable intake were issued in 1998, recommending 600 g/d (potatoes not included). This paper is based on a national dietary survey in 1995 (n = 3098, age range 1-80 years) supplemented with data from a simple frequency survey in 1995 (n = 1007, age range 15-80 years) and from the first national survey in 1985 (n = 2242, age range 15-80 years). Only data on adults are included in this paper. Fat intake, saturated fat in particular, is too high (median intake 37 %energy and 16 %energy, respectively). Main fat sources are separated fats (butter, margarine, oil, etc.: 40%), meat (18%), and dairy products (21%). Total fat intake decreased from 1985 to 1995 but fatty acid composition did not improve. Dietary fibre intake is from 18 to 22 g/d (women and men, respectively) with 62% from cereals, 24% from vegetables and 12% from fruit. Mean intake of vegetables and potatoes was from 200 to 250 g/d (women and men, respectively). Mean intake of fruit and vegetables (potatoes not included) was 277 g/d, or less than half of the new recommendation (600 g/d). Only 15% of participants in the frequency survey reported consuming both fruit and vegetables every day, and only 28% reported to do so almost every day. In conclusion, dietary intake in Denmark is characterized by a high intake of saturated fat and total fat, and by a relatively low intake of fruit and vegetables.

[Food consumption of the population. Trends followed via telephone interviews]. / Befolkningens fødevareforbrug. Udviklingen følges via telefoninterview.

This study aimed at establishing and evaluating a simple method for surveilling trends in consumption of 10 nutritionally important foods. The method is based on food frequency questions combined with questions on the previous days intake, collected through telephone interviews. Participants (461 men, 546 women, 15-60+ yrs) came from a population sample. Between 22 and 69% consumed the foods in question as frequently as prescribed by the Danish food recommendations (lowest for fish and for vegetables, highest for potatoes/rice/pasta). Characteristic sex and age differences were observed, similar to findings from traditional, quantitative food surveys in Denmark. The food frequency results were confirmed by results from the previous day's intake. Crossing of frequencies for different foods gave additional information on consumption patterns. The results indicate that this very simple method may be a useful supplement to traditional quantitative dietary surveys for surveilling trends in food consumption. The Danish Nutrition Council therefore aims at doing similar surveys every other year.

Iodine. Do we need an enrichment program in Denmark?

A working group was established to evaluate the need for iodine enrichment in Denmark. Judged from studies of urinary iodine excretion and one dietary survey the intake of iodine in Denmark is low compared with recommended intakes. The occurrence of non-toxic goitre is relatively high; between 9 and 13% in elderly women. Furthermore, a high occurrence of toxic goitre has been seen in the western part of Denmark. On the other hand, an increased or a high intake of iodine may lead to hyperthyroidism and thyroiditis. The working group concluded that an increase in iodine intake in the Danish population is needed and the best way to achieve this is to iodize all salt. To avoid side effects of a sudden large increase in iodine intake the initial amount of iodine in salt will only be 2 ppm.

Biomarkers of habitual fish intake in adipose tissue.

The association between habitual fish and marine n-3 polyunsaturated fatty acid (PUFA) intake, and the fatty acid composition of subcutaneous fat was studied in 24 healthy young volunteers. Habitual dietary intakes were estimated from three 7-d weighted food records made at months 0, 5, and 8 of the 8-mo study period. The adipose tissue fatty acid composition of each individual was determined by gas chromatography as the mean of two gluteal biopsies, obtained in the first and the last month of the study. The daily consumption of fish and of marine n-3 PUFAs in absolute terms (g/d) was significantly associated with adipose tissue docosahexaenoic acid content (DHA; r = 0.55 and 0.58, respectively, P < 0.001), but not with eicosapentaenoic and docosapentaenoic acid contents. Our study indicates that the adipose tissue DHA content is the biomarker of choice for the assessment of long-term habitual dietary intakes of fish and marine n-3 PUFAs.

Coronary heart disease risk factors, physical activity, and fitness in young Danes.

In a random sample of young Danish adults (86 men and 115 women, 23-27 yr of age) maximal oxygen uptake (VO2max), physical activity (PA), blood pressure, blood lipids, body fat content, and smoking habits were studied. Cholesterol, triglyceride and body fat related negatively to VO2max. The ratio HDL/total cholesterol was positively related to VO2max (r = 0.3, P < 0.001), but no relationship was observed for HDL cholesterol. No association was found between PA and any of the risk factors. The relationships between different measures of PA and directly measured VO2max was around r = 0.3. No relationship existed between heart rate recorded during submaximal testing and PA (r = 0.0), which indicates that the method of assessing VO2max is important in demonstrating relationships to PA and risk factors. In conclusion, a favorable coronary heart disease risk profile was related to a higher VO2max, but not to time spent on physical activity. This suggests that in this age group intensity must be high enough to have an effect on VO2max before a preventive effect is present.

Validity of individual portion size estimates in a food frequency questionnaire.

BACKGROUND: Dietary surveys often rely upon subjects' ability to estimate their portion sizes instead of weighing them, but information on the validity of such estimates is lacking. This study investigated the validity of estimated portion sizes from a self-administered food frequency questionnaire including photos. METHODS: Validity was evaluated by comparison with portion sizes from 14-day weighed food records. Eight sets of photos were included in the study (three meat dishes, one fish dish, three vegetables, potatoes), each set with four options. Subjects (59 men, 85 women) were 40-64 years. RESULTS: The majority of subjects (85-95%) selected the most correct photo or a neighbouring photo. However, regression analyses showed that the relationship between the estimated and the measured portion sizes was relatively weak for most of the foods tested, and correlations were only significant for three of the eight foods. This apparent contradiction was partly due to the pattern of the error: subjects selecting small portions had underestimated their actual portions while subjects selecting large portions had overestimated them. This error pattern could not be explained by the theoretical error resulting from the use of four discrete portion sizes instead of continuous weights, neither was it a simple consequence of the unidirectional errors at the extreme ends. Actual portion sizes varied from day to day, with intra-individual coefficients of variation of 34-40%. CONCLUSIONS: The photos used in the present study were of limited value for ranking individuals correctly according to their actual portion sizes. Whether this is a common feature of photos used in food frequency questionnaires remains to be answered.

Changes in CHD risk factors with age: a comparison of Danish adolescents and adults.

In 1983 a representative sample of Danish adolescents 16-19 yr of age were selected to participate in a study to determine risk profile for coronary heart disease. Eight years later (1991), we performed a follow-up study of the same participants 23-27 yr of age to compare risk factors. In the young adults power was generally high, 48.0 (SD +/- 7.8) and 39.6 (SD +/- 6.5) ml.min-1.kg-1 for men and women, respectively. Only 30% of the men and 26% of the women did not regularly participate in sport activities. Seventy-five percent of both genders bicycled daily, 50% of the men and 42% of the women as their daily transportation year round. Twenty percent, more men than women, were considered to be inactive. Women had a higher ratio of HDL-C/C than men (0.32 for women vs 0.26 for men). Mean values for blood pressure were 134/83 mm Hg and 122/78 mm Hg for men and women, respectively. Thirty-eight percent of the men and 10% of the women had an elevation above 140/90 mm Hg in either systolic blood pressure (SBP) or diastolic blood pressure (DBP). Cholesterol levels were high (10%) when compared with the U.S. population, but triglyceride levels were substantially lower (40%). Comparing the 1991 adults with the 1983 adolescents, the ranges were wider. In conclusion, the risk factor profile changes in men were less favorable than the profile for women; the changes in high risk groups were larger than changes in mean values.

Dietary factors related to fitness in young men and women.

BACKGROUND: In a previous paper we reported an inverse relationship between fitness and serum lipids in this group of young subjects. The present study investigates whether a higher fitness level was associated with a more prudent diet and whether this contributed to the observed relationship between fitness and serum lipids. METHODS: The study sample, comprising 70 women and 49 men ages 23-27 years, was a subgroup of a large random sample. Aerobic fitness was measured directly as maximal oxygen uptake (ml O2 min-1 kg-1) and dietary intake as 7-day food records. RESULTS: The highest fitness tertile had an intake of dietary fiber higher than that of the lowest tertile (25.2 g/10 MJ vs 21.9 g/10 MJ, P < 0.05) and a lower intake of sucrose (7.2 E% vs 9.8 E%, P < 0.01), whereas total fat intake and the ratio between polyunsaturated and saturated fatty acids were similar (35.4 E% vs 36.5 E%, P > 0.05, 0.39 vs 0.34, P > 0.05, respectively). No differences were observed in intake of alcohol, protein, and total carbohydrate. Multiple regression analyses showed no impact of dietary variables upon the relationship between serum lipids and fitness. CONCLUSIONS: Better fitness was associated with a better dietary composition with respect to dietary fiber and sucrose, but not to fat. The observed inverse relationship between fitness and serum lipids was not related to diet.