A preventive effect of dietary marine n−3 fatty acids on early delivery and toxaemia has recently been hypothesized. In only one published controlled trial fish oil has been given to pregnant women, namely in that conducted during 1938–9 in London by the People's League of Health with a dietary supplement containing vitamins, minerals, and halibut liver oil. Although it was of high quality and its findings are hitherto unexplained, neglect and misinterpretation of the trial seem to occur commonly in reviews. Of the 5644 women who were enrolled the 622 withdrawals were independent of treatment. Alternate allocation to treatment was used, producing two groups that were well balanced as to age and parity. The supplement was given from about week 20. The control group did not receive any supplement. Reductions of 20.4% (95% confidence interval 9–30%, P = 0.00083) and 31.5% (95% confidence interval 11–47%, P = 0.0047) were seen in odds of delivering before 40 weeks of gestation and pre-eclampsia respectively. No significant effects were seen on perinatal mortality, average birth weight, deliveries after 40 weeks, hypertension in the absence of oedema and proteinuria, duration of labour, sepsis or breast-feeding occurrence. Later controlled trials with vitamins or minerals given in the same amounts as in this trial have largely failed to show convincing effects as seen here. A controlled trial assessing the isolated effects of fish oil in pregnancy is warranted.

The composition of 500 foods has been stored in a computer in order to analyse a child's diet. The methodology of operations research is applied to a very simple problem: a diet with only two foods. The geometrical representation of the ‘feasible region’ and of the ‘objective function’ is illustrated. One of the analytical methods employable with many variables (foods) is considered. This method was used in trying to find diets allowing for the preferential use of selected foods while respecting recommended dietary allowances, the tastes of the child and other constraints. The theoretical difficulty of transferring this methodology to pediatric dietetics was examined. We solved a simple case utilizing this procedure.

The body composition of thirty-eight Granadina goat kids was measured. Six animals were slaughtered at birth while the remainder were kept individually at an environmental temperature of 24±2° and a relative humidity of 60±5%. They were given goat's milk or a milk-substitute at two planes of nutrition until 15 or 30 d of age and then slaughtered. The goat's milk and milk-substitute contained 260.4 and 222.0 g digestible protein/kg and 23.23 and 20.85 MJ metabolizable energy/kg respectively. Voluntary feed intake as metabolizable energy was a function of metabolic body-weight (kg W0.75), equivalent to 2.42 and 2.44 times the energy requirement for maintenance for goat's milk- and milk-substitute-fed animals respectively. There was a high degree of correlation between the empty-body concentration of dry matter, fat and energy and empty-body-weight (P < 0.001) or animal age (P < 0.001), and between body-weight and animal age (P < 0.001). The relationships between empty-body composition and empty-body-weight were independent of type of milk or plane of nutrition. In contrast relationships between empty-body composition or empty-body-weight and animal age were affected by the type of milk and, over all, by the plane of nutrition. All these results show that in these animals any body-weight will have a similar composition, but it will be reached earlier or later depending on dietary regimen and always with the limitation of voluntary intake.

A study of the dietary intake of 115 male and 217 female mentally handicapped persons aged 15–64 years in five long-stay institutions was carried out using a semi-weighed technique over 4 d. Nineteen per cent of males and 5% of females were classified as being underweight and 15% of males and 27% of females were classified as being obese. The average daily intakes of nutrients were: energy 8.8 MJ, protein 92 g, carbohydrate 218 g, fat 101 g, dietary fibre 18 g, calcium 1024 mg, iron 12.5 mg, vitamin B6 1.4 mg, vitamin B12 10.8 μg, ascorbic acid 68 mg. The distribution of energy between protein, carbohydrate and fat was 18, 39 and 43% respectively. Energy intakes were not related to ambulatory status, degree of mental handicap, the level of drug usage or body mass index. Energy intakes varied significantly between hospitals and between the sexes.

Children (227), aged 7–12 years, weighed and recorded all food and drink consumed for seven consecutive days. Each child completed tests of verbal and non-verbal intelligence, and was then randomly allocated to one of two groups after matching for age, sex, IQ and height. In a double-blind trial lasting for 28 d, one group received a vitamin-mineral supplement daily and the other group a placebo. On re-testing, there were no significant differences in performance between the two groups. Furthermore, there were no consistent correlations between test scores and micronutrient intakes based on the weighed records. Thus, we found no evidence that learning ability in a cross-section of British schoolchildren was limited by the quality of their diets.

Forty pigs (twenty males and twenty females) were weaned at 4 weeks of age into individual cages, and their weights and feed intakes measured daily. From weaning to 16 kg live weight they were given free access to a feed with either 134 (L) or 278 (H) g crude protein (nitrogen × 6.25)/kg fresh weight. During this period pigs on feed L grew at a slower rate and converted feed less efficiently than pigs on feed H. At 16 kg live weight they were introduced to a 6 d period of feeding when, on succesive days, they were given feeds L, H, L, H, L and H (if previously fed on L) or feeds H, L, H, L, H and L (if previously fed on H). For pigs previously given access to feed L the live-weight gain was 1061 v. 575 g/d on the days when H or L was given; the feed intake was 1078 v. 1027 g/d respectively. For pigs previously given access to feed H, the live-weight gain was 655 v. 610 g/d and the feed intake 844 v. 1071 g/d on the days when H or L were given. The interactions between the feed given previously and the feed given for the 3 d of the subsequent 6 d period were highly significant for both live-weight and feed intake. These rapid changes in feed intake and growth rate suggest that the metabolism of young pigs is extremely flexible, with a rapid rate of response to a change in the protein content of their feed.

Subjects aged 16–64 years (592; 258 men and 334 women), randomly selected from the population of Northern Ireland, kept a 7 d weighed record of all food and drink consumed. Social, personal and anthropometric data were also collected. From the weighed records food consumption was described in terms of forty-one food groups. Using principal components analysis, four distinct dietary patterns were generated which were identified as a traditional diet, a cosmopolitan diet, a convenience diet and a ‘meat and two veg’ diet. These dietary patterns were then correlated with sociocultural, lifestyle and anthropometric variables. It is clear that dietary behaviour is influenced by a number of inter-related sociocultural demographics and that identifiable population groups in Northern Ireland have different dietary behaviours.

Heat production (HP) and the intake and retention of energy and nitrogen were measured at 20° in growing female broiler fowl given diets with metabolizable energy (ME) contents ranging from 8 to 15 MJ/kg at each of two crude protein (nitrogen × 6.25; CP) contents (130 and 210 g/kg). ME intake was partially controlled by the birds, but increased by 30% over the range of dietary ME concentration. CP intake varied directly with dietary CP:ME ratio, indicating that control of energy intake took priority and that food intake did not increase in order to enhance amino acid intake on low-CP diets. Maintenance energy requirement and fasting HP were not affected by diet. Although the HP of fed birds was significantly affected by dietary energy source, there was no evidence for regulatory diet-induced thermogenesis as energy intake increased. Total energy retention doubled on the higher-energy diets as a result of increased intake and retention efficiency in the absence of any compensation by diet-induced thermogenesis. The proportion of energy retained as fat was negatively correlated with dietary CP:ME ratio. It was concluded that the growing female broiler fowl responded to large differences in energy intake and dietary CP concentration not by changes in rate of energy dissipation as heat but by changes in the quantity of energy retained and in the partition of retained energy between body protein and body fat.

Energy intake and expenditure in women runners and non-runners were assessed by weighed food records, evaluation of minute-by-minute activity diaries, and indirect calorimetry. All participants were adapted to their stated activity levels for at least 6 months and maintained a constant body-weight throughout their participation. Calculated daily energy intake equalled calculated expenditure in non-runners (7300 (SD 1536) v. 7476 (SD 872) kJ/d), but calculated energy expenditure in women running about 54 km/week was found to exceed intake by more than 2700 kJ/d (8259 (SD 1466) v. 10963 (SD 1367), P < 0.01). The runners showed no evidence of compensating for the increased energy expenditure associated with running by engaging in lower-intensity activities during non-running time. Further, runners did not decrease energy expended at various activities. The findings suggest that women adapted to high levels of activity may possess mechanisms to maintain body-weight without significantly increasing energy intake.

Full blood counts, serum ferritin, vitamin B12 and folate, erythrocyte folate concentrations and nutrient intakes were estimated in twenty-three Indian vegetarian, twenty-two Caucasian omnivores and eighteen Caucasian vegetarian women aged 25–40 years. Energy and copper intakes were lower in the Indian women than in the Caucasians. Intakes of dietary fibre, vitamin C and folate were greater and the proportion of energy derived from fat was lower in the vegetarians than in the omnivores. Vitamin B12 and protein intakes were lower in both vegetarian groups than in the omnivores. Fe intake was similar in all the groups but haem Fe provided one-quarter of the Fe intake of the omnivores. Haemoglobin concentrations were generally inside the normal range in all groups, but were lower in the Indians as were mean corpuscular volume (MCV) and mean corpuscular haemoglobin (MCH). Higher MCV, MCH and lower erythrocyte (RBC) counts were observed in Caucasian vegetarians compared with the Caucasian omnivores. In both groups of vegetarians, concentrations of serum vitamin B12 and ferritin were markedly lower than in the omnivores. RBC folate concentrations were lower in the Indians than in either of the Caucasian groups when subjects taking supplements were excluded. It is concluded that vegetarians need to ensure they have adequate intakes of Fe and vitamin B12.

Thirty-two 160 kg dairy heifers were used to measure the effects of increasing dietary protein content on growth and heat production. A basal diet containing (g/kg) 550 sodium hydroxide-treated straw, 220 barley, 220 sugarbeet pulp and 10 urea was offered with 0, 76 and 152 g fishmeal/kg dry matter of the basal diet (F0, F1 and F2 levels respectively). The three diets were each given at two levels of feeding (low, L; high, H): 57.6 g/d per kg metabolic body-weight (W0.75) for the LF0 diet and 74.7 g/d per kg W0.75 for the HFO diet. Apparent digestibility of the diets increased in response to the addition of fishmeal. Mean dry matter digestibility values were 0.67, 0.67, 0.69, 0.66, 0.68 and 0.69 and those for acid-detergent fibre digestibility were 0.60, 0.63, 0.66, 0.58, 0.60 and 0.65 for diets LF0, LF1, LF2, HF0, HF1 and HF2 respectively. Nitrogen retention increased in response to both fishmeal and feeding level. Live-weight gains were 170, 296, 434 g/d for the LF0, LF1 and LF2 diets and 468, 651 and 710 g/d for the HF0, HF1 and HF2 diets respectively. There were significant effects of increasing the plane of feeding and the level of fishmeal in the diet on live-weight gain. Dietary effects on live-weight gains were accompanied by increases in mean energy retention of 23, 45, 82, 94, 160 and 152 kJ/d per kg W0.75 for diets LF0, LF1, LF2, HF0, HF1 and HF2 respectively, but no definite evidence was obtained that dietary supplementation with fishmeal modified the efficiency of utilization of metabolizable energy for growth.

The effect of meal composition and energy content on the thermic effect of food (TEF) was investigated in sixteen adult, non–obese female subjects. Each subject consumed four different test meals, each meal on a different day. Meals were of high-carbohydrate-low-fat (HCLF) with 0.70, 0.19 and o.11 of the energy content from carbohydrate, fat and protein respectively, and low-carbohydrate-high–fat (LCHF) with 0.24, 0.65 and 0.11 of the energy content from carbohydrate, fat and protein respectively. The energy contents of the test meals for each composition were 2520 kJ (600 kcal) and 5040 kJ (1200 kcal). The basal metabolic rate (BMR) and the postprandial metabolic rate (PP-MR) were measured by open-circuit indirect calorimetry using the Douglas bag technique while the subjects were in the supine position. The mean BMR value was 3.63 (SE 0.07) kJ/min (0.87 kcal/min (SE 0.17)). The 5 H-TEF value for the 2520 kJ (600 kcal) HCLF meal was 228 (SE 11.8) kJ (54 kcal (SE 2.8)) and for the LCHF meal was 228 (SE 9.6) kJ (54 kcal (SE 2.3)). The corresponding values for the 5040 kJ (1200 kcal) meals were 356 (SE 20.4) kJ (85 kcal (SE 4.9)) and 340 (SE 15.8) kJ (81 kcal (SE 3.8)). There was no significant (P =0.49) effect of meal composition on TEF, but the energy content of the meals had a significant (P < 0.001) effect on TEF. In all subjects and for all meals, PP-MR had not returned to premeal level 5 h after a meal, indicating that the TEF values measured underestimate total TFF. The present study suggests that TEF is significantly influenced by the energy content of a meal but not by meal composition.

A study was conducted to investigate the effect of differential dose levels of methylxanthines on lactational performance, with respect to milk volume and composition and pup growth. The methylxanthines; caffeine, theophylline and theobromine, were administered via drinking water in the proportions occurring in tea, at a dose of 50, 1 and 2 mg/kg body-weight respectively to Wistar albino rats throughout pregnancy and for up to the 14th day of lactation. A fourth group received a mixture of all three methylxanthines. Maternal food and fluid intake and weight changes, as well as weight gain in the litter were monitored thrice weekly. Milk samples were collected from the dams on days 7 and 14 of lactation, while milk volume was measured on days 12–13 by a method using tritiated water. Results showed that caffeine and theobromine significantly enhanced litter weight (P < 0.01 and 0.05 respectively). In the caffeine group, enhanced litter growth was due to a significant increase (P < 0.05) in milk volume, consequent to increased maternal food intake (P < 0.05). In the theobromine group there was only a weak association between increased litter weight and milk volume. Theophylline had no effect on the volume or composition of milk, or litter weight. The combination of all three methylxanthines also failed to produce any of the positive effects observed with separate drug treatments.

About 450 pregnant women from a low-income group were recruited to study the effect of vitamin A supplementation on plasma vitamin A levels in the mother and cord and on the birth weights of the neonates. Results showed that supplementation with 1800 μg vitamin A/d for more than 12 weeks prevented the decline in plasma vitamin A that otherwise occurs during the last few weeks of pregnancy. This improvement in maternal values for vitamin A at a critical time of development favourably affected availability to the fetus, as reflected by the marked elevation in cord levels. Supplementation for a period of 12 weeks was found to be sufficient, since subsequent discontinuation did not alter the beneficial response. Apart from increasing maternal and cord vitamin A levels, vitamin A supplementation along with iron prevented, in this study, the significant decline in haemoglobin occurring at 26–28 weeks of gestation. The birth weights were not altered by vitamin A supplementation.

The aims of the present study were to compare the gastric emptying of dry matter (DM) and liquids during the feeding period with that following meal consumption, to clarify the relationship between feeding and gastric emptying, and to investigate how gastric emptying changes in growing animals. The studies were performed in pigs fitted with a gastric cannula and fed on a normal finely ground solid diet mixed with water containing CrEDTA as liquid marker. Gastric emptying was measured using a gastric evacuation technique. It was observed that between 0.75 and 6 h after feeding the total amounts emptied increased, but the proportion of the meal emptied fell, with increase in meal size; emptying of both DM and liquids with large and small meals followed and exponential pattern. In contrast, while the animals were feeding, there was linear and rapid emptying of both DM and liquids following a very short (approximately 2 min) lag phase before emptying began. The rate of emptying increased linearly with body-;weight (by 0.55 g DM/min and by 0.24 ml/min per kg body-weight over the range 58–200 kg) such that the emptying of digestible energy per kg metabolic body-weight (W0.75) was roughly maintained (between 2.9 and 3.2 kJ/min per kg W0.75). This suggests that the rate of emptying may be linked in some way with the metabolic requirements of the body. The biphasic pattern of gastric emptying observed is probably the intrinsic pattern of emptying of a meal which does not require breakdown of particles before emptying can occur.