British Journal of Nutrition

1. Twenty-four energy and nitrogen balances were determined using twenty-four crossbred cows (Brown Swiss × Sahiwal) during their midstage of lactation. Energy balances were estimated by subtracting milk energy and heat production from the metabolizable energy (me) intake. Heat production was estimated by indirect calorimetry, by collection and analysis of respiratory gases. The cows were given amounts corresponding to 90, 110 and 130 % of the me and 90 and 110% of the digestible crude protein (DCP) standards of the (US) National Research Council (1966).

2. Energy requirements were estimated by partitioning the me intake for maintenance, milk production and energy gain or loss by multiple regression of energy balance values. Heat production (and thus energy balance) was corrected for excess N intake.

3. Energy requirements for maintenance were 585.18, 580.17 and 574.41 kJ me/kg body-weight^0.75 per d for cows in negative balance, cows in positive balance and for all cows, respectively.

4. The efficiency of utilization of me for milk production was 68.52, 65.48 and 66.12% respectively, for cows in negative balance, for cows in positive balance and all cows. Energy required per kg fat-corrected milk production was 4.580, 4.791 and 4.746 MJ me for the respective groups of cows.

5. The efficiency of utilization of me for tissue gain was 67.67 and 64.86 % for cows in positive balance and for all cows respectively.

Cognition is a field of thought processes by which an individual processes information through skills of perception, thinking, memory, learning and attention. Zinc deficiency may affect cognitive development by alterations in attention, activity, neuropsychological behavior and motor development. The exact mechanisms are not clear but it appears that zinc is essential for neurogenesis, neuronal migration, synaptogenesis and its deficiency could interfere with neurotransmission and subsequent neuropsychological behavior. Studies in animals show that zinc deficiency during the time of rapid brain growth, or during the juvenile and adolescent period affects cognitive development by decreasing activity, increasing emotional behavior, impairing memory and the capacity to learn. Evidence from human studies is limited. Low maternal intakes of zinc during pregnancy and lactation were found to be associated with less focused attention in neonates and decreased motor functions at 6 months of age. Zinc supplementation resulted in better motor development and more playfulness in low birth weight infants and increased vigorous and functional activity in infants and toddlers. In older school going children the data is controversial but there is some evidence of improved neuropsychological functions with zinc supplementation. Additional research is required to determine the exact biological mechanisms, the critical periods, the threshold of severity and the long-term effects of zinc deprivation on cognitive development.

Recent studies have shown that micronutrients are involved in the pathology of type 2 diabetes. Antioxidant effects of vitamins C and B₂and homocysteine-lowering effects of vitamins B₆, folate and B₁₂may have protective roles. However, a few reports have investigated the association between dietary water-soluble vitamin intakes and risk of diabetes. In a prospective study encompassing 19 168 healthy Japanese men and women aged 40–79 years, we examined the associations between dietary intakes of water-soluble vitamins, determined by a validated self-administered FFQ, with the risk of 5-year cumulative incidence of type 2 diabetes by using the logistic regression model. Within the 5-year period, there were 494 self-reported new cases of diabetes. Higher dietary intakes of vitamins C, B₂and folate were associated with lower risk of incident diabetes only in women, whereas no associations of dietary intakes of vitamins B₁, B₃, B₅, B₆and B₁₂were observed in either sex. The multivariable OR in the highestv. the lowest quartile of intakes among women were 0·61 (95 % CI 0·44, 0·94;P-trend = 0·04) for vitamin C, 0·56 (95 % CI 0·34, 0·93;P-trend = 0·03) for vitamin B₂and 0·70 (95 % CI 0·46, 0·98;P-trend = 0·03) for folate. Other than that for sex (P< 0·05), theP-interactions with age, BMI, smoking status or having a family history of diabetes were >0·10. In conclusion, higher dietary intakes of vitamins C, B₂and folate, but not other water-soluble vitamins, were associated with reduced risk of type 2 diabetes in Japanese women.

The health benefits of seafood are well documented and based on the unique supply ofn-3 highly unsaturated fatty acids (HUFA). Aquaculture now contributes about 50 % of food-grade seafood globally and Atlantic salmon (Salmo salar) is a rich source ofn-3 HUFA. However, salmon and other oily fish can accumulate lipophilic persistent organic pollutants (POP), including dioxins (PCDD/F), polychlorinated biphenyls (PCB) and polybrominated diphenyl ethers (PBDE), derived largely from feed. In the present study, triplicate groups of salmon, of initial weight 0·78 kg, were fed one of three experimental diets for 11 weeks. The diets were coated with either a northern fish oil (FO) with a high POP content (cNFO), the same oil that had been decontaminated (deNFO) or a blend of southern fish oil, rapeseed and soyabean oils (SFO/RO/SO). Dietary PCDD/F+dioxin-like PCB (DL-PCB) concentrations were 17·36, 0·45 and 0·53 ng toxic equivalents (TEQ)/kg, respectively. After 11 weeks, the flesh concentrations in fish fed the cNFO, deNFO and SFO/RO/SO diets were 6·42, 0·34 and 0·41 ng TEQ/kg, respectively. There were no differences in flesh EPA and DHA between fish fed the cNFO or deNFO diets although EPA and DHA were reduced by 50 and 30 %, respectively, in fish fed the SFO/RO/SO diet. Thus, decontaminated FO can be used to produce salmon high inn-3 HUFA and low in POP. Salmon produced using deNFO would be of high nutritional value and very low in POP and would utilise valuable fish oils that would otherwise be destroyed due to their high pollutant concentrations.

Maternal dietary patterns and macronutrients intake have been shown to affect the development of gestational diabetes mellitus (GDM), but the findings are inconsistent. We aimed to identify maternal dietary patterns and examine their associations with GDM risk, and to evaluate the contributions of macronutrients intake to these associations. We included 2755 Chinese pregnant women from the Tongji Maternal and Child Health Cohort. Dietary intakes were assessed using a validated semi-quantitative FFQ 2 weeks before the diagnosis of GDM. GDM (n 248) was diagnosed based on the results of a 75-g, 2-h oral glucose tolerance test at 24–28 weeks gestation. We derived five different dietary patterns from a principal component analysis. The results showed that high fish–meat–eggs scores, which were positively related to protein intake and inversely related to carbohydrate intake, were associated with a higher risk of GDM (adjusted OR for quartile 4 v. quartile 1: 1·83; 95 % CI 1·21, 2·79; P_trend=0·007) and higher plasma glucose levels. In contrast, high rice–wheat–fruits scores, which were positively related to carbohydrate intake and inversely related to protein intake, were associated with lower risk of GDM (adjusted OR for quartile 3 v. quartile 1: 0·54; 95 % CI 0·36, 0·83; P_trend=0·010) and lower plasma glucose levels. In addition, dietary protein and carbohydrate intake significantly contributed to the associations between dietary patterns and GDM risk or glucose levels. These findings suggest that a dietary pattern characterised by high protein and low carbohydrate intake in pregnancy was associated with a higher risk of GDM, which may provide important clues for dietary guidance during pregnancy to prevent GDM.

The present study analysed the effects of the flavanol ( − )-epicatechin in rats after chronic inhibition of NO synthesis with N^G-nitro-l-arginine methyl ester (l-NAME), at doses equivalent to those achieved in the studies involving human subjects. Wistar rats were randomly divided into four groups: (1) control-vehicle, (2) l-NAME, (3) l-NAME-epicatechin 2 (l-NAME-Epi 2) and (4) l-NAME-epicatechin 10 (l-NAME-Epi 10). Rats were daily given by oral administration for 4 weeks: vehicle, ( − )-epicatechin 2 or 10 mg/kg. Animals in the l-NAME groups daily received l-NAME 75 mg/100 ml in drinking-water. The evolution in systolic blood pressure and heart rate, and morphological and plasma variables, proteinuria, vascular superoxide, reactivity and protein expression at the end of the experiment were analysed. Chronic ( − )-epicatechin treatment did not modify the development of hypertension and only weakly affected the endothelial dysfunction induced by l-NAME but prevented the cardiac hypertrophy, the renal parenchyma and vascular lesions and proteinuria, and blunted the prostanoid-mediated enhanced endothelium-dependent vasoconstrictor responses and the cyclo-oxygenase-2 and endothelial NO synthase (eNOS) up-regulation. Furthermore, ( − )-epicatechin also increased Akt and eNOS phosphorylation and prevented the l-NAME-induced increase in systemic (plasma malonyldialdehyde and urinary 8-iso-PGF_2α) and vascular (dihydroethidium staining, NADPH oxidase activity and p22^phox up-regulation) oxidative stress, proinflammatory status (intercellular adhesion molecule-1, IL-1β and TNFα up-regulation) and extracellular-signal-regulated kinase 1/2 phosphorylation. The present study shows for the first time that chronic oral administration of ( − )-epicatechin does not improve hypertension but reduced pro-atherogenic pathways such as oxidative stress and proinflammatory status of the vascular wall induced by blockade of NO production.

1. The milk production of one mother was determined post-partum for a period of 13 weeks, during which time breast milk was her infant's only source of food energy. The weight changes of both the mother and the male infant were recorded during this period.

2. The food intake and activity pattern of the mother were also recorded for 4-week periods: at 2, 6, 10 weeks after birth and 2 weeks after the cessation of lactation, which was maintained for a period of 27 weeks.

3. The infant regained his birth weight of 3310 g on the 14th day of life. His weight gain for the duration of the study, which averaged 233 g/week, was considered satisfactory.

4. The daily milk production increased gradually from an average of 241 g during the 1st week post-partum to 995 g during the 12th week. The infant's maximum milk intake and hence food energy intake per kg body-weight was (range) 198–204 g milk and 550–560kJ/kg respectively during the 3rd to the 7th week, followed by a gradual decrease from the 8th to the 13th week after birth.

5. The estimated efficiency of energy coversion for breast-milk production was consistent with other values reported in the literature.

1. Complete 24 h energy and nitrogen balances were measured for eight subjects both while consuming a basal diet supplemented with 49 g saccharose/d (diet S) and while consuming the same basal diet but supplemented with 50 g lactitol monohydrate/d (diet L).

2. The subjects ate the two diets for 8 d. Faeces and urine were collected for the final 4 d. Exchange of respiratory gases (oxygen, carbon dioxide, hydrogen and methane) was measured during the final 72 h while the subjects stayed in an open-circuit respiration chamber, 11 m³, and simulated office work. Before eating diet L, subjects ate 50 g lactitol daily for 10 d.

3. On diets L and S, faecal moisture content averaged 0.787 and 0.753 g/g respectively, the difference being significant (P < 0.05). On diet L, energy and nitrogen digestibilities and energy metabolizability averaged 0, 922, 0.836 and 0-881 respectively, and on diet S 0.935, 0.869 and 0.896 respectively; the differences were also significant (P < 0.05). Urinary energy losses and N balances were not significantly different for the two diets.

4. In all subjects only traces of methane were produced but hydrogen production differed significantly (P < 0.05) for diets L and S, being 2.3 and 0.4 litres (normal temperature and pressure)/d respectively.

5. Intakes of metabolizable energy (ME) were corrected, within subjects, to energy equilibrium and equal metabolic body-weight. The corrected ME intakes did not show differences between diets. However, when on diet L the subjects were probably less active than when on diet S because differences within subjects of ankle actometer counts between diets showed a high correlation with the corresponding differences in corrected ME intakes (r 0.92). Further correction of ME intake toward equal actometer activity showed a significant (P < 0.05) difference between diets: for maintaining energy equilibrium 5.6 (SE 0.8; P < 0.05) % more ME from diet L was needed than from diet S. The reliability of this 5.6% difference depends on whether or not one ankle actometer gives an accurate picture of the subject's physical activity.

6. The energy contribution to the body is clearly smaller from lactitol than from saccharose, certainly due to the effect of lactitol on digestion, and probably also due to the effect on the utilization of ME.

1. Young male rats were fed on a pelleted stock diet or a variety of palatable food items (‘cafeteria’ diet) and housed at 24° or 29°.

2. ‘Cafeteria’ feeding at the lower temperature stimulated energy intake, gain and expenditure, but reduced energetic efficiency such that over 70% of the excess intake was expended.

3. Housing at 29° suppressed intake and expenditure in animals on both diets, but to a greater extent in ‘cafeteria’-fed rats and energetic efficiency was greater than control values at this higher temperature.

4. The thermogenic capacity of brown fat (mitochondrial purine nucleotide binding) was increased by ‘cafeteria’ feeding, but was suppressed in animals kept at 29°.

5. The results demonstrate that diet-induced thermogenesis is inhibited by high environmental temperatures.

Tissue ascorbic acid (AA) contents of approximately 12 and 100% saturation respectively were produced in two groups of guinea-pigs. The ‘low-AA’ group had significantly lower muscle carnitine concentrations than the ‘high-AA’group. There was no concomitant emergence of the symptoms customarily regarded as characteristic of hypovitaminosis C. It is concluded that muscle carnitine (β-OH-γ-(trimethylamino) butyric acid) is a highly-sensitive indicator of tissue AA contents; this could account for the lassitude and fatigue reported to precede the emergence of frank scurvy in man.