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result(s) for
"Knuthsen, Pia"
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Discrimination of conventional and organic white cabbage from a long-term field trial study using untargeted LC-MS-based metabolomics
by
Husted, Søren
,
Knuthsen, Pia
,
Thorup-Kristensen, Kristian
in
Agricultural management
,
Agricultural practices
,
Agricultural production
2014
The influence of organic and conventional farming practices on the content of single nutrients in plants is disputed in the scientific literature. Here, large-scale untargeted LC-MS-based metabolomics was used to compare the composition of white cabbage from organic and conventional agriculture, measuring 1,600 compounds. Cabbage was sampled in 2 years from one conventional and two organic farming systems in a rigidly controlled long-term field trial in Denmark. Using Orthogonal Projection to Latent Structures-Discriminant Analysis (OPLS-DA), we found that the production system leaves a significant (p = 0.013) imprint in the white cabbage metabolome that is retained between production years. We externally validated this finding by predicting the production system of samples from one year using a classification model built on samples from the other year, with a correct classification in 83 % of cases. Thus, it was concluded that the investigated conventional and organic management practices have a systematic impact on the metabolome of white cabbage. This emphasizes the potential of untargeted metabolomics for authenticity testing of organic plant products.
Journal Article
Evaluation of Web-based Dietary Assessment Software for Children: comparing reported fruit, juice and vegetable intakes with plasma carotenoid concentration and school lunch observations
by
Andersen, Lene F.
,
Knuthsen, Pia
,
Christensen, Tue
in
Beverages
,
Biological and medical sciences
,
biomarkers
2013
Web-based Dietary Assessment Software for Children (WebDASC) was developed to estimate dietary intake in a school meal intervention study among 8- to 11-year-old Danish children. The present study validates self-reported fruit, juice and vegetable (FJV) intakes in 8- to 11-year-old children by comparing intake with plasma carotenoid concentration, and by comparing the reported FJV intake to actually eaten FJV, as observed by a photographic method. A total of eighty-one children, assisted by parents, reported their diet for seven consecutive days. For the same five schooldays as they reported their diet, the children's school lunch was photographed and weighed before and after eating. In the week after the diet reporting, fasting blood samples were taken. Self-reported intake of FJV and estimated intake of carotenoids were compared with plasma carotenoid concentration. Accuracy of self-reported food and FJV consumption at school lunch was measured in terms of matches, intrusion, omission and faults, when compared with images and weights of lunch intake. Self-reported intake of FJV was significantly correlated with the total carotenoid concentration (0·58) (P< 0·01). Fruit and juice consumption showed higher correlations than vegetables with plasma carotenoid concentration (0·38 and 0·42 v. 0·33) (P< 0·01). A total of 82 % of the participants fell into the same or adjacent quartiles when cross-classified by FJV intake and carotenoids biomarkers. WebDASC attained 82 % reporting matches overall and a higher percentage match for reporting fruits compared with beverages. The present study indicated that WebDASC can be used to rank 8- to 11-year-old Danish children according to their intake of FJV overall and at school meals.
Journal Article
The Nutritional Quality of Lunch Meals Eaten at Danish Worksites
by
Knuthsen, Pia
,
Lassen, Anne D.
,
Bysted, Anette
in
Adult
,
chemical analysis
,
confidence interval
2018
Monitoring the nutritional environment is important to help inform future initiatives to improve access to healthy foods. The objective was to examine the nutritional quality of lunch meals eaten at 15 worksite canteens and then to compare with results from a study conducted 10 years before. The duplicate-portion-technique with subsequent chemical analysis was used to quantify 240 customers’ lunch intake. Estimated mean energy intake was 2.1 MJ/meal (95% confidence interval (CI): 1.9 to 2.4 g/meal) and estimated energy density 599 kJ/100 g (95% CI 550 to 653 kJ/100 g). Energy density of the male participants’ meals were significantly higher compared with the female participants’ meals (+55 kJ/100 g, 95% CI: +12 to +98 kJ/100 g, p = 0.012), whereas no gender differences were found in macronutrient distribution or fruit and vegetable intake. Compared to the study conducted 10 years before several significant changes were observed, including an increase in mean estimated intake of fruit and vegetables (+38 g/meal, 95% CI: 19 to 57 g/meal, p < 0.001) and a decrease in energy density (−76 kJ/100 g, 95% CI: −115, −37 kJ/100 g, p < 0.001). In conclusion, this study suggests an equalization of gender differences in fruit and vegetable intake and a possible improvement in the nutritional quality of canteen lunch meals over a 10-year period.
Journal Article
The Salt Content of Lunch Meals Eaten at Danish Worksites
2018
Monitoring levels of sodium (salt) in meals consumed out-of-home is needed to support effective implementation of salt-reduction strategies. The objective of the study was to examine lunch salt intake at 15 worksite canteens and to compare with results from a comparable study conducted 10 years before. A duplicate-portion-technique with subsequent chemical analysis was used to quantify 240 customers’ lunch salt intake. Estimated mean salt intake was 2.6 g/meal (95% Cl: 2.2 to 3.0 g/meal) and 0.78 g/100 g (95% Cl: 0.69 to 0.88 g/100 g). Salt intake measured both as g per meal and per 100 g was found to be significantly higher for male compared with female participants (+0.10 g/100 g, 95% Cl: +0.02 to +0.17 g/100 g, p = 0.011). Compared with the study conducted 10 years before, there was a significantly lower estimated salt intake of 0.5 g/meal (95% CI: −0.8 to −0.2 g/meal, p = 0.001), suggesting a possible reduction in canteen lunch salt intake during a 10-year period. Still, 40% of the meals exceeded the Nordic Keyhole label requirements of maximum 0.8 g salt per 100 g for ready meals. A further reduction of salt intake is warranted to comply with salt reduction targets.
Journal Article
Iodine excretion has decreased in Denmark between 2004 and 2010 – the importance of iodine content in milk
2014
Fortification with the essential trace element iodine is widespread worldwide. In the present study, results on iodine excretion and intake of iodine-rich foods from a cross-sectional study carried out in 2004–5, 4 to 5 years after the implementation of mandatory iodine fortification, were compared with data in a study carried out in 2008–10. The 2008–10 study was a follow-up of a cross-sectional study carried out before iodine fortification was implemented. Participants in the cross-sectional studies were randomly selected. Both studies were carried out in the cities of Aalborg and Copenhagen in Denmark. The median urinary iodine concentration decreased in women from 97 μg/l (n 2862) to 78 μg/l (n 2041) (P< 0·001). The decrease persisted after adjustment for age, city and education, and if expressed as estimated 24 h iodine excretion. The prevalence of users of iodine containing dietary supplements increased from 29·4 to 37·3 % (P< 0·001). The total fluid intake increased in women (P< 0·001), but the intake of other iodine-rich foods did not change. The median urinary iodine concentration did not change in men (114 μg/l (n 708) and 107 μg/l (n 424), respectively), while the total fluid intake decreased (P= 0·001). Iodine content was measured in milk sampled in 2000–1 and in 2013. The iodine content was lower in 2013 (12 (sd 3) μg/100 g) compared with that in 2000–1 (16 (sd 6) μg/100 g) (P< 0·001). In conclusion, iodine excretion in women has decreased below the recommended level. The reason might probably, at least partly, be a decreased content of iodine in milk.
Journal Article
Relative bioavailability of the flavonoids quercetin, hesperetin and naringenin given simultaneously through diet
2010
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)(0−48h) and C(max) values for quercetin and hesperetin were similar, whereas the AUC(0−48h) 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.
Journal Article
Discrimination of conventional and organic white cabbage from a long-term field trial study using untargeted LC-MS-based metabolomics
2014
The influence of organic and conventional farming practices on the content of single nutrients in plants is disputed in the scientific literature. Here, large-scale untargeted LC-MS-based metabolomics was used to compare the composition of white cabbage from organic and conventional agriculture, measuring 1,600 compounds. Cabbage was sampled in 2 years from one conventional and two organic farming systems in a rigidly controlled long-term field trial in Denmark. Using Orthogonal Projection to Latent Structures-Discriminant Analysis (OPLS-DA), we found that the production system leaves a significant (p = 0.013) imprint in the white cabbage metabolome that is retained between production years. We externally validated this finding by predicting the production system of samples from one year using a classification model built on samples from the other year, with a correct classification in 83% of cases. Thus, it was concluded that the investigated conventional and organic management practices have a systematic impact on the metabolome of white cabbage. This emphasizes the potential of untargeted metabolomics for authenticity testing of organic plant products.
Journal Article