Sarcopenia (loss of muscle mass/strength) burdens many older adults – hospitalised older adults being particularly vulnerable. Treating the condition, protein supplementation (PrS) and resistance training (RT) may act synergistically. Therefore, this block-randomised, double-blind, multicentre intervention study, recruiting geriatric patients > 70 years from three medical departments, investigated the effect of PrS combined with RT during hospitalisation and 12 weeks after discharge. Participants were randomly allocated (1:1) to receive PrS (totally 27·5 g whey protein/d, about 2000 kJ/d) or isoenergetic placebo-products (< 1·5 g protein/d) divided into two servings per d to supplement the habitual diet. Both groups were engaged in a standardised, progressive low-intensity RT programme for the lower extremities (hospital: supervised daily/after discharge: self-training 4×/week). From April 2016 to September 2017, 2351 patients were screened, 462 were eligible, and 165 included. Fourteen were excluded and ten dropped out, leaving 141 participants in the intention-to-treat analysis. The average total protein intake during hospitalisation/after discharge was 1·0 (interquartile range (IQR) 0·8, 1·3)/1·1 (IQR 0·9, 1·3) g/kg per d (protein-group) and 0·6 (IQR 0·5, 0·8)/0·9 (IQR 0·6, 1·0) g/kg per d (placebo group). Both groups improved significantly for the primary and secondary endpoints of muscle mass/strength, functional measurements and quality of life, but no additional effect of PrS was seen for the primary endpoint (30-s chair stand test, repetitions, median changes from baseline: (standard test: 0 (IQR 0, 5) (protein group) v. 2 (IQR 0, 6) (placebo group) and modified test: 2 (IQR 0, 5) (protein group) v. 2 (IQR −1, 5) (placebo group)) or any secondary endpoints (Mann–Whitney U tests, P > 0·05). In conclusion, PrS increasing the total protein intake by 0·4 and 0·2 g/kg per d during hospitalisation and after discharge, respectively, does not seem to increase the adaptive response to low-intensity RT in geriatric medical patients.

A low-energy diet (LED) is an effective approach to induce a rapid weight loss in individuals with overweight. However, reported disproportionally large losses of fat-free mass (FFM) after an LED trigger the question of adequate protein content. Additionally, not all individuals have the same degree of weight loss success. After an 8-week LED providing 5020 kJ/d for men and 4184 kJ/d for women (84/70 g protein/d) among overweight and obese adults, we aimed to investigate the relationship between protein intake relative to initial FFM and proportion of weight lost as FFM as well as the individual characteristics associated with weight loss success. We assessed all outcomes baseline and after the LED. A total of 286 participants (sixty-four men and 222 women) initiated the LED of which 82 % completed and 70 % achieved a substantial weight loss (defined as ≥8 %). Protein intake in the range 1·0–1·6 g protein/d per kg FFM at baseline for men and 1·1–2·2 g protein/d per kg FFM at baseline for women was not associated with loss of FFM (P = 0·632). Higher Three-Factor Eating Questionnaire (TFEQ) hunger at baseline and reductions in TFEQ disinhibition and hunger during the LED were associated with larger weight loss (all P ≤ 0·020); whereas lower sleep quality at baseline predicted less successful weight loss using intention to treat analysis (P = 0·021), possibly driven by those dropping out (n 81, P = 0·067 v. completers: n 198, P = 0·659). Thus, the protein intakes relative to initial FFM were sufficient for maintenance of FFM and specific eating behaviour characteristics were associated with weight loss success.

The aim of the study was to assess whether a simple substitution of carbohydrate in the conventionally recommended diet with protein and fat would result in a clinically meaningful reduction in postprandial hyperglycaemia in subjects with type 2 diabetes mellitus (T2DM). In all, sixteen subjects with T2DM treated with metformin only, fourteen male, with a median age of 65 (43–70) years, HbA1c of 6·5 % (47 mmol/l) (5·5–8·3 % (37–67 mmol/l)) and a BMI of 30 (sd 4·4) kg/m2 participated in the randomised, cross-over study. A carbohydrate-reduced high-protein (CRHP) diet was compared with an iso-energetic conventional diabetes (CD) diet. Macronutrient contents of the CRHP/CD diets consisted of 31/54 % energy from carbohydrate, 29/16 % energy from protein and 40/30 % energy from fat, respectively. Each diet was consumed on 2 consecutive days in a randomised order. Postprandial glycaemia, pancreatic and gut hormones, as well as satiety, were evaluated at breakfast and lunch. Compared with the CD diet, the CRHP diet reduced postprandial AUC of glucose by 14 %, insulin by 22 % and glucose-dependent insulinotropic polypeptide by 17 % (all P<0·001), respectively. Correspondingly, glucagon AUC increased by 33 % (P<0·001), cholecystokinin by 24 % (P=0·004) and satiety scores by 7 % (P=0·035), respectively. A moderate reduction in carbohydrate with an increase in fat and protein in the diet, compared with an energy-matched CD diet, greatly reduced postprandial glucose excursions and resulted in increased satiety in patients with well-controlled T2DM.

The aim of the present study was to investigate the associations between the habitual Ca intake and faecal fat and energy excretion as well as blood lipid profile in free-living normal-weight and overweight individuals. The participants were enrolled for an 8-d period where data from a 7-d diet registration (days 1–7), a 5-d faeces collection (days 3–7), a 2-d urine collection (days 5–7), and anthropometric measurements and a fasting blood sample (day 8) were collected. Analyses showed that dietary Ca intake (g/10 MJ per d) was positively associated with excretion of faecal fat (P = 0·004) and energy (P = 0·031) when adjusted for BMI, age, sex and intake of Ca-containing supplements. However, after adjustment for intake of fibre, the effect of Ca intake disappeared. Nevertheless, total cholesterol (CHOL) and LDL-CHOL concentrations were associated negatively with Ca intake (β −0·62 (95 % CI −0·96, −0·28) mmol/l, P < 0·001, and β −0·49 (95 % CI −0·78, −0·20) mmol/l, P = 0·001, respectively, per 1000 mg/10 MJ per d increase in Ca intake). In conclusion, incorporation of Ca-rich food products in a habitual diet was associated with reduced total CHOL and LDL-CHOL concentrations, which may lower the risk of CVD in the long term.

Our dietary habits affect both cognitive performance and mood. The aim of the study was to examine the effect of increased availability of healthy meals and water at work on healthcare staff. The study used an 8-week randomised cross-over design. A total of sixty physicians, nurses and nursing assistants, including sixteen working on shifts, were recruited. The participants received a self-selected keyhole-labelled (Nordic nutrition label) lunch, snack and bottled water during each shift throughout the intervention period. Reaction time (Go/No-Go test), mood-related scores (POMS) and dietary intake were assessed at run-in, and at the end of the intervention and the control periods. The intake of fat (P=0·030) and PUFA (P=0·003) was lower, and the intake of carbohydrate (P=0·008), dietary fibre (P=0·031) and water (P<0·001) was greater in the intervention period than in the control period. The intervention had no effect on reaction time or any of the mood-related scores in the group as a whole. In shift-working participants, the intervention period resulted in a 31·1 % lower Fatigue-Inertia Score (P=0·003), a 15·3 % higher Vigour-Activity Score (P=0·041) and a 42·7 % lower Total Mood Disturbance Score (P=0·017), whereas the only dietary component that significantly improved was water intake (P=0·034), when compared with the control period. Providing healthy meals, snacks and water during working hours seems to be an effective way of improving employees’ dietary intake. Moreover, increased intake of water may be associated with beneficial effects on fatigue, vigour and total mood in shift-working healthcare staff.

In a longitudinal study including 642 healthy 8–11-year-old Danish children, we investigated associations between vitamin D dependent SNP and serum 25-hydroxyvitamin D (25(OH)D) concentrations across a school year (August–June). Serum 25(OH)D was measured three times for every child, which approximated measurements in three seasons (autumn, winter, spring). Dietary and supplement intake, physical activity, BMI and parathyroid hormone were likewise measured at each time point. In all, eleven SNP in four vitamin D-related genes: Cytochrome P450 subfamily IIR1 (CYP2R1); 7-dehydrocholesterol reductase/nicotinamide adenine dinucleotide synthetase-1(DHCR7/NADSYN1); group-specific complement (GC); and vitamin D receptor were genotyped. We found minor alleles of CYP2R1 rs10500804, and of GC rs4588 and rs7041 to be associated with lower serum 25(OH)D concentrations across the three seasons (all P<0·01), with estimated 25(OH)D differences of −5·8 to −10·6 nmol/l from major to minor alleles homozygosity. In contrast, minor alleles homozygosity of rs10741657 and rs1562902 in CYP2R1 was associated with higher serum 25(OH)D concentrations compared with major alleles homozygosity (all P<0·001). Interestingly, the association between season and serum 25(OH)D concentrations was modified by GC rs7041 (Pinteraction=0·044), observed as absence of increase in serum 25(OH)D from winter to spring among children with minor alleles homozygous genotypes compared with the two other genotypes of rs7041 (P<0·001). Our results suggest that common genetic variants are associated with lower serum 25(OH)D concentrations across a school year. Potentially due to modified serum 25(OH)D response to UVB sunlight exposure. Further confirmation and paediatric studies investigating vitamin D-related health outcomes of these genotypic differences are needed.

Angiopoietin-like protein 4 (ANGPTL4) is a lipoprotein lipase inhibitor that is involved in lipid metabolism and angiogenesis. Animal studies have suggested that the ANGPTL4 protein is modulated by the gut microbiota, possibly through increased concentrations of SCFA, such as C4, found in whole-fat milk or as a result of fermentation of inulin. This study investigated whether a standardised diet either high in fat content or supplemented with inulin powder would increase plasma ANGPTL4 in overweight men and whether this increase was mediated through a compositional change of the gut microbiota. The study had a crossover design with three arms, where participants were given a standardised isoenergetic diet supplemented with inulin powder, whole-fat milk or water (control). Plasma and urine samples were collected before and after each intervention period. Faecal samples and adipose tissue biopsies were collected after each intervention period. The study included twenty-one participants of whom eighteen completed the study. The dietary interventions did not change ANGPTL4 plasma concentration, nor was plasma ANGPTL4 associated with plasma lipids, TAG or NEFA concentration. The relative abundance of bifidobacteria following the inulin diet was higher, compared with the control diet. However, the changes in microbiota were not associated with plasma ANGPTL4 and the overall composition of the microbiota did not change between the dietary periods. Although weight was maintained throughout the dietary periods, weight was negatively associated with plasma ANGPTL4 concentration. In the adipose tissue, ANGPTL4 expression was correlated with leptin expression, but not with hypoxia-inducible factor 1α (HIF-1α) expression.

Sufficient summer/autumn vitamin D status appears important to mitigate winter nadirs at northern latitudes. We conducted a cross-sectional study to evaluate autumn vitamin D status and its determinants in 782 Danish 8–11-year-old children (55°N) using baseline data from the Optimal well-being, development and health for Danish children through a healthy New Nordic Diet (OPUS) School Meal Study, a large randomised controlled trial. Blood samples and demographic and behavioural data, including 7-d dietary recordings, objectively measured physical activity, and time spent outdoors during school hours, were collected during September–November. Mean serum 25-hydroxyvitamin D (25(OH)D) was 60·8 (sd 18·7) nmol/l. Serum 25(OH)D levels ≤50 nmol/l were found in 28·4 % of the children and 2·4 % had concentrations <25 nmol/l. Upon multivariate adjustment, increasing age (per year) (β −2·9; 95 % CI −5·1, −0·7 nmol/l), female sex (β −3·3; 95 % CI −5·9, −0·7 nmol/l), sampling in October (β −5·2; 95 % CI −10·1, −0·4 nmol/l) and November (β −13·3; 95 % CI −17·7, −9·1), and non-white ethnicity (β −5·7; 95 % CI −11·1, −0·3 nmol/l) were negatively associated with 25(OH)D (all P<0·05). Likewise, immigrant/descendant background was negatively associated with 25(OH)D, particularly in females (β −16·3; 95 % CI −21·9, −10·7) (P<0·001) (Pinteraction=0·003). Moderate-to-vigorous physical activity (MVPA) (min/d) (β 0·06; 95 % CI 0·01, 0·12), outdoor walking during school hours (min/week) (β 0·4; 95 % CI 0·1, 0·6) and intake of vitamin D-containing supplements ≥3 d/week (β 8·7; 95 % CI 6·4, 11·0) were positively associated with 25(OH)D (all P<0·05). The high proportion of children with vitamin D status below the recommended sufficiency level of 50 nmol/l raises concern as levels expectedly drop further during winter months. Frequent intake of vitamin D supplements was strongly associated with status. MVPA and outdoor activity during school hours should be investigated further in interventions to improve autumn vitamin D status in children at northern latitudes.

Vitamin D status has been associated with cardiometabolic markers even in children, but the associations may be confounded by fat mass and physical activity behaviour. This study investigated associations between vitamin D status and cardiometabolic risk profile, as well as the impact of fat mass and physical activity in Danish 8–11-year-old children, using baseline data from 782 children participating in the Optimal well-being, development and health for Danish children through a healthy New Nordic Diet (OPUS) School Meal Study. We assessed vitamin D status as serum 25-hydroxyvitamin D (25(OH)D) and measured blood pressure, fasting plasma glucose, homoeostasis model of assessment-insulin resistance, plasma lipids, inflammatory markers, anthropometry and fat mass by dual-energy X-ray absorptiometry, and physical activity by 7 d accelerometry during August–November. Mean serum 25(OH)D was 60·8 (sd 18·7) nmol/l. Each 10 mmol/l 25(OH)D increase was associated with lower diastolic blood pressure (−0·3 mmHg, 95 % CI −0·6, −0·0) (P=0·02), total cholesterol (−0·07 mmol/l, 95 % CI −0·10, −0·05), LDL-cholesterol (−0·05 mmol/l, 95 % CI −0·08, −0·03), TAG (−0·02 mmol/l, 95 % CI −0·03, −0·01) (P≤0·001 for all lipids) and lower metabolic syndrome (MetS) score (P=0·01). Adjustment for fat mass index did not change the associations, but the association with blood pressure became borderline significant after adjustment for physical activity (P=0·06). In conclusion, vitamin D status was negatively associated with blood pressure, plasma lipids and a MetS score in Danish school children with low prevalence of vitamin D deficiency, and apart from blood pressure the associations were independent of body fat and physical activity. The potential underlying cause–effect relationship and possible long-term implications should be investigated in randomised controlled trials.

Fe and n-3 long-chain PUFA (n-3 LCPUFA) have both been associated with cognition, but evidence remains inconclusive in well-nourished school-aged children. In the Optimal Well-Being, Development and Health for Danish Children through a Healthy New Nordic Diet (OPUS) School Meal Study, the 3-month intervention increased reading performance, inattention, impulsivity and dietary intake of fish and Fe. This study investigated whether the intervention influenced n-3 LCPUFA and Fe status and, if so, explored how these changes correlated with the changes in cognitive performance. The study was a cluster-randomised cross-over trial comparing school meals with packed lunch (control). At baseline and after each treatment, we measured serum ferritin, whole-blood n-3 LCPUFA and Hb, and performance in reading, mathematics and d2-test of attention. Data were analysed using mixed models (n 726) and principal component analysis of test performances (n 644), which showed two main patterns: ‘school performance’ and ‘reading comprehension’. The latter indicated that children with good reading comprehension were also more inattentive and impulsive (i.e. higher d2-test error%). The intervention improved ‘school performance’ (P=0·015), ‘reading comprehension’ (P=0·043) and EPA+DHA status 0·21 (95 % CI 0·15, 0·27) w/w % (P<0·001), but it did not affect serum ferritin or Hb. At baseline, having small Fe stores was associated with poorer ‘school performance’ in girls, but with better ‘reading comprehension’ in both boys and girls. Both baseline EPA+DHA status and the intervention-induced increase in EPA+DHA status was positively associated with ‘school performance’, suggesting that n-3 LCPUFA could potentially explain approximately 20 % of the intervention effect. These exploratory associations indicate that increased fish intake might explain some of the increase in reading performance and inattention in the study.

A New Nordic Diet (NND) was developed in the context of the Danish OPUS Study (Optimal well-being, development and health for Danish children through a healthy New Nordic Diet). Health, gastronomic potential, sustainability and Nordic identity were crucial principles of the NND. The aim of the present study was to investigate the effects of serving NND school meals compared with the usual packed lunches on the dietary intake of NND signature foods. For two 3-month periods, 834 Danish children aged 8–11 years received NND school meals or their usual packed lunches brought from home (control) in random order. The entire diet was recorded over 7 consecutive days using a validated Web-based Dietary Assessment Software for Children. The NND resulted in higher intakes during the entire week (% increase) of root vegetables (116 (95 % CI 1·93, 2·42)), cabbage (26 (95 % CI 1·08, 1·47)), legumes (22 (95 % CI 1·06, 1·40)), herbs (175 (95 % CI 2·36, 3·20)), fresh berries (48 (95 % CI 1·13, 1·94)), nuts and seeds (18 (95 % CI 1·02, 1·38)), lean fish and fish products (47 (95 % CI 1·31, 1·66)), fat fish and fish products (18 (95 % CI 1·02, 1·37)) and potatoes (129 (95 % CI 2·05, 2·56)). Furthermore, there was a decrease in the number of children with zero intakes when their habitual packed lunches were replaced by NND school meals. In conclusion, this study showed that the children increased their intake of NND signature foods, and, furthermore, there was a decrease in the number of children with zero intakes of NND signature foods when their habitual packed lunches were replaced by school meals following the NND principles.

Children's vitamin D intake and status can be optimised to meet recommendations. We investigated if nutritionally balanced school meals with weekly fish servings affected serum 25-hydroxyvitamin D (25(OH)D) and markers related to bone in 8- to 11-year-old Danish children. We conducted an explorative secondary outcome analysis on data from 784 children from the OPUS School Meal Study, a cluster-randomised cross-over trial where children received school meals for 3 months and habitual lunch for 3 months. At baseline, and at the end of each dietary period, 25(OH)D, parathyroid hormone (PTH), osteocalcin (OC), insulin-like growth factor-1 (IGF-1), bone mineral content (BMC), bone area (BA), bone mineral density (BMD), dietary intake and physical activity were assessed. School meals increased vitamin D intake by 0·9 (95 % CI 0·7, 1·1) μg/d. No consistent effects were found on 25(OH)D, BMC, BA, BMD, IGF-1 or OC. However, season-modified effects were observed with 25(OH)D, i.e. children completing the school meal period in January/February had higher 25(OH)D status (5·5 (95 % CI 1·8, 9·2) nmol/l; P = 0·004) than children completing the control period in these months. A similar tendency was indicated in November/December (4·1 (95 % CI –0·12, 8·3) nmol/l; P = 0·057). However, the effect was opposite in March/April (–4·0 (95 % CI –7·0, –0·9) nmol/l; P = 0·010), and no difference was found in May/June (P = 0·214). Unexpectedly, the school meals slightly increased PTH (0·18 (95 % CI 0·07, 0·29) pmol/l) compared with habitual lunch. Small increases in dietary vitamin D might hold potential to mitigate the winter nadir in Danish children's 25(OH)D status while higher increases appear necessary to affect status throughout the year. More trials on effects of vitamin D intake from natural foods are needed.

The gut microbiota has been implicated in obesity and its progression towards metabolic disease. Dietary interventions that target the gut microbiota have been suggested to improve metabolic health. The aim of the present study was to investigate the effect of interventions with Lactobacillus paracasei F19 or flaxseed mucilage on the gut microbiota and metabolic risk markers in obesity. A total of fifty-eight obese postmenopausal women were randomised to a single-blinded, parallel-group intervention of 6-week duration, with a daily intake of either L. paracasei F19 (9·4 × 1010 colony-forming units), flaxseed mucilage (10 g) or placebo. Quantitative metagenomic analysis of faecal DNA was performed to identify the changes in the gut microbiota. Diet-induced changes in metabolic markers were explored using adjusted linear regression models. The intake of flaxseed mucilage over 6 weeks led to a reduction in serum C-peptide and insulin release during an oral glucose tolerance test (P< 0·05) and improved insulin sensitivity measured by Matsuda index (P< 0·05). Comparison of gut microbiota composition at baseline and after 6 weeks of intervention with flaxseed mucilage showed alterations in abundance of thirty-three metagenomic species (P< 0·01), including decreased relative abundance of eight Faecalibacterium species. These changes in the microbiota could not explain the effect of flaxseed mucilage on insulin sensitivity. The intake of L. paracasei F19 did not modulate metabolic markers compared with placebo. In conclusion, flaxseed mucilage improves insulin sensitivity and alters the gut microbiota; however, the improvement in insulin sensitivity was not mediated by the observed changes in relative abundance of bacterial species.

It is widely assumed that nutrition can improve school performance in children; however, evidence remains limited and inconclusive. In the present study, we investigated whether serving healthy school meals influenced concentration and school performance of 8- to 11-year-old Danish children. The OPUS (Optimal well-being, development and health for Danish children through a healthy New Nordic Diet) School Meal Study was a cluster-randomised, controlled, cross-over trial comparing a healthy school meal programme with the usual packed lunch from home (control) each for 3 months (NCT 01457794). The d2 test of attention, the Learning Rating Scale (LRS) and standard tests on reading and mathematics proficiency were administered at baseline and at the end of each study period. Intervention effects were evaluated using hierarchical mixed models. The school meal intervention did not influence concentration performance (CP; primary outcome, n 693) or processing speed; however, the decrease in error percentage was 0·18 points smaller (P< 0·001) in the intervention period than in the control period (medians: baseline 2·03 %; intervention 1·46 %; control 1·37 %). In contrast, the intervention increased reading speed (0·7 sentence, P= 0·009) and the number of correct sentences (1·8 sentences, P< 0·001), which corresponded to 11 and 25 %, respectively, of the effect of one school year. The percentage of correct sentences also improved (P< 0·001), indicating that the number correct improved relatively more than reading speed. There was no effect on overall math performance or outcomes from the LRS. In conclusion, school meals did not affect CP, but improved reading performance, which is a complex cognitive activity that involves inference, and increased errors related to impulsivity and inattention. These findings are worth examining in future trials.

An increasing number of children are exhibiting features of the metabolic syndrome (MetS) including abdominal fatness, hypertension, adverse lipid profile and insulin resistance. Healthy eating practices during school hours may improve the cardiometabolic profile, but there is a lack of evidence. In the present study, the effect of provision of school meals rich in fish, vegetables and fibre on a MetS score (primary outcome) and on individual cardiometabolic markers and body composition (secondary outcomes) was investigated in 834 Danish school children. The study was carried out as a cluster-randomised, controlled, non-blinded, cross-over trial at nine schools. Children aged 8–11 years received freshly prepared school lunch and snacks or usual packed lunch from home (control) each for 3 months. Dietary intake, physical activity, cardiometabolic markers and body composition were measured at baseline and after each dietary period. The school meals did not affect the MetS score (P= 1·00). However, it was found that mean arterial pressure was reduced by 0·4 (95 % CI 0·0, 0·8) mmHg (P= 0·04), fasting total cholesterol concentrations by 0·05 (95 % CI 0·02, 0·08) mmol/l (P= 0·001), HDL-cholesterol concentrations by 0·02 (95 % CI 0·00, 0·03) mmol/l, TAG concentrations by 0·02 (95 % CI 0·00, 0·04) mmol/l (both P< 0·05), and homeostasis model of assessment-insulin resistance by 0·10 (95 % CI 0·04, 0·16) points (P= 0·001) compared with the control diet in the intention-to-treat analyses. Waist circumference increased 0·5 (95 % CI 0·3, 0·7) cm (P< 0·001), but BMI z-score remained unaffected. Complete-case analyses and analyses adjusted for household educational level, pubertal status and physical activity confirmed the results. In conclusion, the school meals did not affect the MetS score in 8–11-year-olds, as small improvements in blood pressure, TAG concentrations and insulin resistance were counterbalanced by slight undesired effects on waist circumference and HDL-cholesterol concentrations.

Casein and whey differ in amino acid composition and in the rate of absorption; however, the absorption rate of casein can be increased to mimic that of whey by exogenous hydrolysis. The objective of the present study was to compare the effects of hydrolysed casein (HC), intact casein (IC) and intact whey (IW) on energy expenditure (EE) and appetite regulation, and thereby to investigate the influence of amino acid composition and the rate of absorption. In the present randomised cross-over study, twenty-four overweight and moderately obese young men and women consumed three isoenergetic dietary treatments that varied in protein source. The study was conducted in a respiration chamber, where EE, substrate oxidation and subjective appetite were measured over 24 h at three independent visits. Moreover, blood and urine samples were collected from the participants. The results showed no differences in 24 h and postprandial EE or appetite regulation. However, lipid oxidation, estimated from the respiratory quotient (RQ), was found to be higher after consumption of IW than after consumption of HC during daytime (P= 0·014) as well as during the time after the breakfast meal (P= 0·008) when the food was provided. Likewise, NEFA concentrations were found to be higher after consumption of IW than after consumption of HC and IC (P< 0·01). However, there was no overall difference in the concentration of insulin or glucagon-like peptide 1. In conclusion, dietary treatments when served as high-protein mixed meals induced similar effects on EE and appetite regulation, except for lipid oxidation, where RQ values suggest that it is higher after consumption of IW than after consumption of HC.

The OPUS (Optimal well-being, development and health for Danish children through a healthy New Nordic Diet (NND)) School Meal Study investigated the effects on the intake of foods and nutrients of introducing school meals based on the principles of the NND covering lunch and all snacks during the school day in a cluster-randomised cross-over design. For two 3-month periods, 834 Danish children aged 8–11 years from forty-six school classes at nine schools received NND school meals or their usual packed lunches brought from home (control) in random order. The whole diet of the children was recorded over seven consecutive days using a validated Web-based Dietary Assessment Software for Children. The NND resulted in higher intakes of potatoes (130 %, 95 % CI 2·07, 2·58), fish (48 %, 95 % CI 1·33, 1·65), cheese (25 %, 95 % CI 1·15, 1·36), vegetables (16 %, 95 % CI 1·10, 1·21), eggs (10 %, 95 % CI 1·01, 1·19) and beverages (6 %, 95 % CI 1·02, 1·09), and lower intakes of bread (13 %, 95 % CI 0·84, 0·89) and fats (6 %, 95 % CI 0·90, 0·98) were found among the children during the NND period than in the control period (all, P< 0·05). No difference was found in mean energy intake (P= 0·4), but on average children reported 0·9 % less energy intake from fat and 0·9 % higher energy intake from protein during the NND period than in the control period. For micronutrient intakes, the largest differences were found for vitamin D (42 %, 95 % CI 1·32, 1·53) and iodine (11 %, 95 % CI 1·08, 1·15) due to the higher fish intake. In conclusion, the present study showed that the overall dietary intake at the food and nutrient levels was improved among children aged 8–11 years when their habitual packed lunches were replaced by school meals following the principles of the NND.

For decades, it has been debated whether high protein intake compromises bone mineralisation, but no long-term randomised trial has investigated this in children. In the family-based, randomised controlled trial DiOGenes (Diet, Obesity and Genes), we examined the effects of dietary protein and glycaemic index (GI) on biomarkers of bone turnover and height in children aged 5–18 years. In two study centres, families with overweight parents were randomly assigned to one of five ad libitum-energy, low-fat (25–30 % energy (E%)) diets for 6 months: low protein/low GI; low protein/high GI; high protein/low GI; high protein/high GI; control. They received dietary instructions and were provided all foods for free. Children, who were eligible and willing to participate, were included in the study. In the present analyses, we included children with data on plasma osteocalcin or urinary N-terminal telopeptide of collagen type I (U-NTx) from baseline and at least one later visit (month 1 or month 6) (n 191 in total, n 67 with data on osteocalcin and n 180 with data on U-NTx). The level of osteocalcin was lower (29·1 ng/ml) in the high-protein/high-GI dietary group than in the low-protein/high-GI dietary group after 6 months of intervention (95 % CI 2·2, 56·1 ng/ml, P= 0·034). The dietary intervention did not affect U-NTx (P= 0·96) or height (P= 0·80). Baseline levels of U-NTx and osteocalcin correlated with changes in height at month 6 across the dietary groups (P< 0·001 and P= 0·001, respectively). The present study does not show any effect of increased protein intake on height or bone resorption in children. However, the difference in the change in the level of osteocalcin between the high-protein/high-GI group and the low-protein/high-GI group warrants further investigation and should be confirmed in other studies.