Free-living energy expenditure was estimated by doubly-labelled water (DLW) and continuous heart-rate (HR) monitoring over nine consecutive days in nine healthy men with sedentary occupations but different levels of leisure-time physical activity. Individual calibrations of the HR-energy expenditure (EE) relationship were obtained for each subject using 30 min average values of HR and EE obtained during 24h whole-body calorimetry with a defined exercise protocol, and additional data points for individual leisure activities measured with an Oxylog portable O2 consumption meter. The HR data were processed to remove spurious values and insert missing data before the calculation of EE from second-order polynomial equations relating EE to HR. After data processing, the HR-derived EE for this group of subjects was on average 0.8 (sem 0.6) MJ/d, or 6.0 (sem 4.2)% higher than that estimated by DLW. The diary-respirometer method, used over the same 9d, gave values which were 1.9 (sem 0.7) MJ/d, or -12.1 (sem 4.0)% lower than the DLW method. The results suggest that HR monitoring can provide a better estimate of 24 h EE of groups than the diary-respirometer method, but show that both methods can introduce errors of 20% or more in individuals.

Concern has been expressed that high dietary concentrations of non-milk extrinsic sugars (NMES) may potentially compromise nutrient intakes in population groups with low energy intakes (Department of Health, 1991). The objective of the present study was to examine data from the National Diet and Nutrition Survey of Children Aged 1.5 to 4.5 years (Gregory et al. 1995) for evidence of an inverse association between energy from NMES and micronutrient intakes, and if possible to quantify a level of NMES-energy at which micronutrient intakes may, theoretically, be compromised. Energy and nutrient intakes were compared across quintiles of NMES-energy for boys (n 848) and girls (n 827). As the concentration of NMES increased, energy intake rose (in boys only) while percentage energy from fat fell from 40 to 32 % across quintiles 1 to 5. Intakes of most micronutrients also fell, while intakes of vitamin C rose. Mean intakes of most micronutrients (Ca, thiamin, riboflavin, niacin, folate and vitamin C) were adequate in comparison with dietary reference values. However, intakes of Fe, Zn and vitamin D were low at all levels of NMES-energy and fell below the estimated average requirement for Fe and Zn for NMES concentrations exceeding 24 % of energy. Lower intakes of milk, meat, bread and vegetables, and higher intakes of fruit juice largely explain the observed trends in micronutrient intake. It is concluded that the inverse association of NMES with micronutrient intakes is of most significance for the 20 % of children with diets highest in NMES. However, further work is required to establish whether the associations observed have biological significance with regard to micronutrient status.

It was nearly 120 years ago that the physiologist Claude Bernard proposed that for an organism to function optimally the component cells must be surrounded by a medium of closely regulated composition (‘La fixité du milieu interne est la condition de la vie libre’). Homeostasis is the term used today to describe this phenomenon, being first coined by Walter B. Cannon in 1929 (Hardy, 1976). This is the underlying physiological principle that explains the relative chemical constancy of the body, including inorganic nutrients such as Fe.

The effect of a daily intake of 14g inulin added to a low-fat spread on fasting blood lipids and gastrointestinal symptoms was investigated in sixty-four young healthy women in a randomized double-blind crossover study involving two periods of 4 weeks. The test spread with and without inulin replaced habitual spread during the test periods. No significant differences between the test periods in plasma total cholesterol, HDL-cholesterol, LDL-cholesterol and triacylglycerol concentrations were observed. Gastrointestinal symptoms assessed with questionnaires showed that in the inulin period there was a significantly (P<0·05) higher degree of discomfort from flatulence and other gastrointestinal symptoms than in the control period. In general, there was no indication of intestinal adaptation to this level of intake of inulin.

The aim of the present study was to validate against the doubly-labelled water (DLW) technique the factorial method and the heart rate (HR) recording method for determining daily energy expenditure (DEE) of elderly people in free-living conditions. The two methods were first calibrated and validated in twelve healthy subjects (six males and six females; 70·1 (sd 2·7) years) from opencircuit whole-body indirect calorimetry measurements during three consecutive days and during 1 d respectively. Mean energy costs of the various usual activities were determined for each subject using the factorial method, and individual relationships were set up between HR and energy expenditure for the HR recording method. In free-living conditions, DEE was determined over the same period of time by the DLW, the factorial and the HR recording methods during 17, 14 and 4 d respectively. Mean free-living DEE values for men estimated using the DLW, the factorial and the HR recording methods were 12·8 (sd 3·1), 12·7 (sd 2·2) and 13·5 (sd 2·7) MJ/d respectively. Mean free-living DEE values for women were 9·6 (sd 0·8), 8·8 (sd 1·2) and 10·2 (sd 1·5) MJ/d respectively. No significant differences were found between the three methods for either sex, using the Bland & Altman (1986) test. Mean differences in DEE of men were -0·9 (sd 11·8) % between the factorial and DLW methods, and +4·7 (sd 16·1) % between the HR recording and DLW methods. Similarly, in women, mean differences were -7·7 (sd 12·7) % between the factorial and DLW methods, and +5·9 (sd 8·8) % between the HR recording and DLW methods. It was concluded that the factorial and the HR recording methods are satisfactory alternatives to the DLW method when considering the mean DEE of a group of subjects. Furthermore, mean energy costs of activities calculated in the present study using the factorial method were shown to be suitable for determining free-living DEE of elderly people when the reference value (i.e. sleeping metabolic rate) is accurately measured.

Trends in global fish catches are described together with fish landlings and fish consumption in the UK. The importance of n–6 and n–3 polyunsaturated fatty acids as essential constituents of human diets is considered and the role of oily fish as a dietary source of the long-chain n–3 polyunsaturates, docosahexaenoic acid and eicosapentaenoic acid, is emphasized. The origin ofn–3 polyunsaturates in the marine phytoplankton and their transmission via zooplankton to fish is described as a means of understanding the consumption of different fish body oils. The ease with which the fatty acid composition of fish body oils can be manipulated by altering the fatty acid composition of their feeds is emphasized and the dietary requirements of marine and freshwater fish for n–3 and n–6 polyunsaturates considered. Farming fish on diets containing principally fish meal and fish oil, as used in salmon production in Scotland, generates a high quality product with levels of long-chain n–3 polyunsaturates equalling or exceeding those of wild fish. Farming fish on high quality marine oils rich in docosahexaenoic and eicosapentaenoic acids is an efficient means of delivering these essential nutrients in human diets and also efficiently exploiting a strictly limited marine bioresource.

Increasing the precision of measurements of total energy expenditure in population-based epidemiological studies is important for accurately quantifying the relationship between this exposure and disease. Current questionnaire-based methods cannot accurately quantify total energy expenditure, although they may provide an estimate of the frequency of vigorous activities. Heart rate monitoring with individual calibration has been advocated as a method for assessing energy expenditure in field studies and has been compared with the ‘gold standard’ techniques of doubly-labelled water and indirect calorimetry. However the method has previously only been used on small and selected populations. This study was, therefore, established to test the feasibility of using heart rate monitoring in a population-based study of adults. A total of 167 individuals aged 30–40 years were randomly selected and underwent 4 d heart-rate monitoring. Only three individuals could not complete the protocol. The mean physical activity level (PAL) measured over 4 d was 1.89 (sd 0.40) in men and 1.76 (sd 0.31) in women. There was no difference between mean PAL on weekend days compared with weekdays (mean paired difference 0.0008, 95% CI −0.06 to + 0.06). The estimate of mean PAL was not correlated with BMI, percentage body fat or the waist:hip ratio. It was, however, correlated with cardio-respiratory fitness as measured by VO2max per kg (Spearman rank correlation coefficient 0.50 in men and 0.42 in women). The pattern of energy expenditure was assessed by calculating the percentage of daytime hours in which PAL was greater than five times basal energy expenditure. This measure was strongly correlated with the mean PAL in both men (Spearman correlation coefficient 0.77) and women (0.71). We conclude that heart-rate monitoring is a feasible method for assessing the pattern and total level of energy expenditure in medium-sized epidemiological studies. It may also prove useful as the reference technique for calibrating questionnaires to estimate energy expenditure in larger scale studies.

The ileal digestibilities of maize starch and native pea starch do not differ. However maize starch is digested faster than pea starch and the ileal amino acid digestibility of a diet containing pea starch is lower. In the present study, the net portal fluxes of glucose, lactate, volatile fatty acids (VFA) and amino acids were measured for diets including 650 g maize starch or pea starch/kg. The diets were fed at a level 870 kJ digestible energy/kg0.75 twice daily (06.00 and 18.00 hours) to four female pigs in a crossover design. Portal vein blood flow did not differ between maize and pea starches (1620 and 1484 ml/min respectively; sed 100; P = 0.23). For maize starch portal glucose flux was significantly higher during the first 6 h after feeding, was not different 8 h after feeding and was significantly lower thereafter. Net portal glucose flux was higher for maize starch than for pea starch (1759 and 1265 mmol/12 h respectively; sed 182; P = 0.054). Net portal lactate flux was not significantly different between maize and pea starches (36.5 and 67.2 mmol/12 h respectively; sed 24.1; P = 0.27) and net portal VFA flux was lower for maize starch than for pea starch (169 and 218 mmol/12 h respectively; SED 18; P = 0.054). Net portal fluxes of valine, isoleucine, phenylalanine, tryptophan, arginine, serine, cystine, tyrosine, lysine, histidine and the sum of essential amino acids tended to be or were higher (P < 0.1 or P<0.05) and net portal flux of aspartic acid tended to be lower for pea starch (P<0.1). It can be concluded that, although ileal digestibility of both starches is equal, the rate of appearance of glucose in the portal vein was higher for maize starch, influencing the net portal flux of amino acids.

Even-numbered dicarboxylic acids (DA) have been proposed as an alternative fuel substrate in parenteral nutrition. In particular, dodecanedioic acid (C12) shows a rapid plasma clearance from tissues, a very low urinary excretion compared with other DA and a high oxidation rate. The aim of the present study was to investigate the effect of C12 infusion on insulin-stimulated glucose uptake in patients with non-insulin-dependent diabetes mellitus (NIDDM) compared with healthy volunteers. A primed-constant infusion of C12 (0·39 mmol/min) was administered over 240 min, and at 120 min a 2 h euglycaemic hyperinsulinaemic clamp was performed. Blood specimens were sampled every 30 min and fractioned urines were collected over 24 h. The levels of C12 were measured by HPLC. Indirect calorimetry was performed continuously during the entire session. Body composition was assessed in all subjects studied to obtain fat-free mass (FFM) values. Whole-body glucose uptake decreased significantly during C12 infusion in both groups, although this effect was much more evident (P < 0·01) in NIDDM patients (52·4 (sd 15·8) % decrease compared with saline) than in controls (25·9 (sd 12·1) % decrease). The M value (μmol/kgffm per min) was reduced by C12 to lower levels in NIDDM patients than in normal controls (12·6 (sd 3·9) ν. 25·9 (sd 4·5), P < 0·01). Urinary excretion of C12 over 24 h was significantly lower in NIDDM patients than in controls (4·26 (sd 0·30) mmol ν. 5·43 (sd 0·48), P < 0·01), corresponding to less than 3 % of the administered dose. The infusion of C12 decreased non-protein RQ significantly in both groups of patients. In conclusion, this study shows, for the first time, that C12 significantly reduces glucose uptake in both normal controls and NIDDM patients, although this sparing effect on glucose uptake is much more pronounced in diabetic patients. These data suggest that C12 decreases glucose uptake and oxidation, mainly through a mechanism of substrate competition. Thus, it might be a useful alternative substrate in enteral or parenteral nutrition, sparing glucose utilization and increasing glycogen stores, in those clinical conditions, like NIDDM, where reduced insulin-induced glucose uptake and oxidation are observed.

The objectives of the present study were to determine the feasibility of using manufactured foods, enriched with eicosapentaenoic acid (EPA) and docosahexaenoic acid(DHA) as a means of increasing the intake of these n−3 polyunsaturated fatty acids (PUFA), and to determine the effect of the consumption of these foods on postprandial lipaemia and other metabolic responses to a high-fat mixed test meal. Nine healthy, normotriacylglycerolaemic, free-living male volunteers (aged 35–60 years) completed the randomized, controlled, single-blind, crossover study. The study consisted of two periods (each of 22d) of dietary intervention, separated by a 5-month washout period. During these two periods the subjects were provided with the manufactured foods enriched with EPA and DHA (n−3 enriched) or identical but unenriched foods (control). A mixed test meal containing 82g fat was given to the fasted subjects on day 22 of each dietary intervention period. Two fasting, and thereafter hourly, blood samples were collected from the subjects for an 8h period postprandially. Plasma triacylglycerol, total and HDL-cholesterol, non-esterified fatty acids (NEFA), glucose and immunoreactive insulin levels, post-heparin lipoprotein lipase (EC 3.1.1.34) activity and the plasma free fatty acid and phospholipid fatty acid compositions were measured. A mean daily intake of 1·4 g EPA + DHA (0·9 g EPA, 0·5 g DHA) was ingested during the n−3-enriched dietary period, which was significantly higher than the intake during the habitual and control periods (P <0·001) assessed by a 3 dweighed food intake. A significantly higher level of EPA + DHA enrichment of the plasma fatty acids and phospholipids (P < 0·001) after the n−3-enriched compared withthe control intervention periods was also found. The energy intake on both of the dietary intervention periods was found to be significantly higher than on the habitual diet (P <0·001), with an increase in body weight of the subjects, which reachedsignificance during the n−3 PUFA-enriched dietary intervention period (P < 0·04). The palatability of the enriched foods was not significantly different from that of the control foods. Significantly higher fasting plasma HDL-cholesterol and glucose concentrations were found after the n-3 PUFA-enriched compared with the control intervention period (P < 0·02 and P < 0·05 respectively). No significant differences were found for the postprandial lipid and hormone measurements, except for significantly lower levels of NEFA at 60min after the n−3-enriched intervention period (P< 0·04). Enriched manufactured foods were a feasible vehicle for increasing n−3 PUFA intake. However the nature of the foods provided as the n−3 vehicle may have contributed to the increased body weight and higher energy intakes which were adverse consequences of the intervention. These factors, together with the short duration of the study may have been reponsible for the failure to observe significant plasma triacylglycerol reductions in response to daily intakes of 1·4g EPA+DHA.

We suggested that food preference depends on the interplay between flavour and post-ingestive effects, and we predicted that protein-restricted lambs would acquire preferences for foods paired with supplemental sources of N, including urea (Expts 1 and 2), casein (Expt 3), and gluten (Expt 4). In each experiment, twenty lambs, in two groups of ten, were conditioned as follows: on odd-numbered days, lambs in group 1 received wheat straw (Expts 1, 3, and 4) or ground barley (Expt 2) flavoured with a distinctive flavour, and lambs in group 2 received the same food but with a different flavour. On even-numbered days, flavours were switched and lambs received capsules containing different amounts of urea (ranging from 0.12 to 0.92 g N/d), casein (ranging from 0.23 to 0.69 g N/d), or gluten (ranging from 0.23 to 0.69 g N/d). After conditioning periods of 8 d, lambs were given a two-choice test to determine preference for flavours paired with N. In Expts 1 and 2, lambs preferred the flavours conditioned with urea at lower doses (0.12 g N/d in Expt 1. 0.23 and 0.46 g N/d in Expt 2), but they avoided the flavour associated with urea at the highest dose (0.23 g N/d in Expt 1 and 0.92 g N/d in Expt 2). In Expts 3 and 4, lambs avoided the flavours associated with the lowest doses of casein or gluten (0.23 g N/d), but they preferred the flavours paired with casein or gluten at higher doses (0.46 and 0.69 g N/d). After conditioning, N administrations were suspended and lambs in Expts 3 and 4 were offered a choice of the two flavours at weekly intervals for 2 weeks (extinction); preferences persisted during extinction. Collectively, these results suggest that the post-ingestive effects of N in different forms and concentrations influenced the development of food preferences by lambs.

It is by no means an exaggeration to say that Dr Widdowson is one of the pioneers of body composition research and her studies in the 1940s and 1950s have laid the foundations of body composition science today. These have included both animal and human studies, although this paper will focus only on the latter. Together with Professor McCance and Christine Spray she was responsible for the analysis of three entire adult human cadavers and that of a 4-year-old child (Widdowson et al. 1951). Further work with Dr Dickerson explored the composition of specific tissues and organs of the body (Widdowson & Dickerson, 1964). These studies provide some of the best direct data on human body composition. Moreover the findings from this work form the basis of the indirect techniques which are used so widely today.

Exchangeable pools of Se after an intravenous injection of 74Se-enriched isotope as sodium selenite were measured in two groups (n 9) of elderly women (free-living aged 64–82 years and institutionalized aged 68–82 years), and a comparison group (n 9) of young women aged 31–40 years to evaluate the effect of age and institutionalization on Se reserves. Dietary Se intake was not different among the three groups. Plasma Se and glutathione peroxidase (EC 1.11.1.9) levels were significantly lower in the institutionalized elderly women (P < 0.05). In each of the three groups, two pools were determined from our model. The size of the first pool and the sum of the two pools were lower in the group of institutionalized elderly women than in the other two groups. The significant correlation between plasma Se level and total Se pool size (r 0.66, P < 0.01) indicated that this last variable could serve as a new marker of Se status. Finally, these data suggest that the Se status of elderly women is more related to lifestyle, in terms of institutionalization or not, than to age per se.

The aims of this study were (1) to compare various measures of I status, and (2) to assess urinary I and thyroid hormone status of residents of two areas of New Zealand where, before the iodization of salt, goitre was endemic due to low soil I. A total of 189 subjects (102 males, eighty-seven females) were recruited from the Dunedin Blood Transfusion Centre, and 144 (sixty-seven males, seventyseven females) from the Waikato Blood Transfusion Centre between November 1993 and June 1994. Blood was taken for thyroid hormone assays, and subjects collected a fasting overnight urine specimen, a double-voided fasting urine sample, and a complete 24 h specimen for iodide and creatinine analyses. Positive correlations (P < 0.0001) between daily iodide excretion and iodide concentrations in fasting and double-voided fasting urines, identical median values for iodide concentrations in the three samples, and similar numbers of subjects classified as at risk from I deficiency disorders according to the International Committee for the Control of Iodine Deficiency Disorders/World Health Organization categories (World Health Organization, 1994) confirmed indications from earlier studies that fasting urine samples were suitable for population studies. However 24 h urinary iodide excretion remains the recommended measure for individual I status. Waikato residents excreted more iodide in urine and all measures were significantly greater than for Otago residents. However median urinary iodide excretions for both areas (60 and 76 μg/d for Otago and Waikato respectively) were considerably lower than those reported previously for New Zealand. Thyroid hormone concentrations were within normal ranges. Our findings suggest that I status of New Zealanders may no longer be considered adequate and may once again be approaching levels of intake associated with clinical I deficiency.

Fat digestion and metabolism differ widely between animal species. In ruminants, dietary fats are hydrogenated in the rumen before intestinal absorption so that absorbed fatty acids (FA) are more saturated than dietary FA. In non-ruminants, intestinal FA digestibility depends on the level of saturation of dietary FA. Fat supplementation of the diet of cows decreases milk protein and has a variable effect on milk fat, depending on the source of dietary lipids. When encapsulated lipids are used, the linoleic acid content of milk is increased, but the organoleptic quality of milk may be altered. Supplementary lipids are incorporated into non-ruminant body fat, whereas de novo lipogenesis is reduced. There is a close relationship between the nature of dietary FA and non-ruminant body FA.

The hepatic responses of late gestation, dry dairy cows to acute (6 h) infusions of an amino acid (AA) mixture (Synthamin; 0.0, 1.1, 2.2, 4.4, 8.8 and 17.6 mmol/min) into the mesenteric vein were determined. Neither blood flow nor O2 consumption across the portal-drained viscera (PDV) and liver was significantly altered by infusion. Similarly, there were no effects on net absorption, or hepatic removal, of acetate, propionate, butyrate or NH3. Glucose PDV appearance was unchanged but hepatic glucose production increased (P = 0.032) by 0.2 mmol/min per mmol/min of AA infused. Additional extraction of alanine, glycine (both infused) and glutamine (not infused) by the liver was sufficient to account for most of the extra C required for glucose synthesis. The N that would be liberated from these glucogenic AA would also account for a large proportion of the increase in urea-N produced in response to the AA infusion. This supports the concept of a correlation between gluconeogenesis and ureagenesis. Furthermore, the amide-N liberated from the extracted glutamine would contribute up to 0.17 of hepatic NH3 flux and assist in balancing N inputs into the carbamoyl phosphate and arginosuccinate entry points of the ornithine cycle. Rates of fractional extraction of the various AA by the liver were best fitted by linear equations, indicating that even at the highest rates of administration (approximately twice maximal physiological absorption) the transport systems were not saturated. Hepatic fractional extractions of infused essential AA were highest for methionine (0.83) and phenylalanine (0.87) with the lowest proportion removed observed for valine (0.25), leucine (0.30), lysine (0.31) and isoleucine (0.49). For the non-essential AA, the highest apparent fractional extractions were for glycine (0–73), arginine (0.79) and tyrosine (0.63) followed by alanine (0.54), proline (0.47) and serine (0–37). Hepatic removal of AA-N exceeded the increase in urea-N formation such that, at the highest rate of infusion, approximately 10 mmol/min of the extracted AA was apparently available for hepatic anabolism, more than is required to account for assumed increases in liver mass and export protein synthesis. Similarly, the amount of AA available for peripheral tissue protein gain, when assessed against phenylalanine supply as the limitation, would be the equivalent of a maximum of 0.5 g protein retained/min (6 mmol AA-N/min). This would provide sufficient AA for replenishment of peripheral (muscle) protein stores plus support of the placenta and fetus.

In a double-blind, placebo-controlled study, thirty-three subjects were allocated to undergo either a 4-week treatment with oral Mg supplementation (Mg(OH)2; 411–548 mg Mg/d) or a placebo. The urinary excretion of Mg increased significantly in both the first 2 weeks and the following 2 weeks of Mg supplementation, while the urinary Na excretion also increased significantly over the experimental period. The systolic and diastolic blood pressure values decreased significantly in the Mg group, but not in the placebo group. The urinary aldosterone excretion and packed cell volume increased significantly during the last 2 weeks of the experimental period compared with the run-in period and first 2 weeks of supplementation. There was a statistically significant positive correlation between the values for urinary noradrenaline excretion and diastolic blood pressure at the end of the supplementation period (both expressed as a percentage of the run-in value). Statistically significant increases in lecithin-cholesterol acyltransferase (EC 2.3.1.43; LCAT), HDL-cholesterol and apolipoprotein AI were also observed after Mg supplementation. A significant positive correlation was observed between the levels of LCAT and urinary Mg excretion for the experimental period (expressed as a percentage of the run-in value). The total cholesterol: HDL-cholesterol ratio decreased significantly during the last 2 weeks of Mg supplementation compared with the first 2 weeks and the run-in periods, but this did not occur in the placebo group. These results suggest that Mg supplementation may lower blood pressure through the suppression of the adrenergic activity and possible natriuresis, while also improving the serum lipids through the activation of LCAT in human subjects.

A model is proposed that allows study of the short-term dynamics of gas exchanges (and heat production) in large open-circuit respiration chambers. The model describes changes in [O2] and [CO2] in the respiration chamber by a series of differential equations based on animal metabolism and physical characteristics of gas exchange. The model structure was similar for O2 and CO2, although model parameters differed. A constant level of O2 consumption (and CO2 production) was assumed for resting animals which was different for fed and fasted animals. The adaptation from a fed to a fasting state was described as a first-order process. Physical activity (standing or sitting) was recorded and was included in the model as a constant. Thermic effect of feed comprised the O2 consumption and CO2 production related to several relatively rapidly occurring processes after ingestion of a meal (e.g. ingestion, digestion or absorption). In the model, these processes were pooled into a single phenomenon. Model parameters were obtained statistically by comparing model predictions (based on the numerically integrated differential equations) with the observed [O2] and [CO2]. The model was evaluated by studying gas exchanges in growing pigs that were fasted for 31 h and re-fed a single meal thereafter. The model fitted the data well over the 47 h measurement range. Traditional methods in which heat production is calculated suffer from noisy data when the interval between observations becomes too short. The proposed method circumvents this by modelling the observed concentration of gases in the respiration chamber rather than the calculated heat production.

The predominant fatty acids in milk are the long-chain fatty acids myristic, palmitic and stearic. These saturated fatty acids account for 75 % of the total fatty acids, with a further 21 % occurring as monounsaturated fatty acids of which the most prevalent is oleic acid. Only 4 g/lOO g of the milk fatty acids are polyunsaturated, occurring mainly as linoleic and linolenic acids. All milk fatty acids are derived, almost equally, from either de novo synthesis or directly from preformed fatty acids in the diet. There are four main dietary sources of fatty acids: forages, oilseeds, fish oil and fat supplements. The digestive tract exerts a profound influence on the fate of dietary fatty acids. The short-chain saturated free fatty acids are absorbed through the walls of the rumen or abomasum into the bloodstream. The medium- and longer-chain saturated fatty acids pass into the small intestine, diffuse across the membrane wall where they are incorporated into lipoproteins and enter the bloodstream via the lymphatic system. The majority of unsaturated fatty acids are extensively hydrogenated in the rumen. However, recent work has shown that the levels of certain saturated fatty acids can be reduced and the levels of oleic, linoleic and linolenic fatty acids increased by feeding oilseeds rich in mono- or polyunsaturated fatty acids. In addition, work reported here has confirmed that eicosapentaenoic and docosahexaenoic acids can be transferred to milk when a diet containing fish oil is fed, but the transfer efficiencies are low

This quotation is perhaps especially appropriate when considering the extensive contributions made by Professor McCance and Dr Widdowson to the field of early nutrition and later development. A detailed knowledge of their work in this area is of undoubted value both in interpreting many recent findings and in the design of new investigations. The first part of this paper presents a brief overview of some of their most significant studies. Their implications at both the fundamental and applied levels are then discussed, especially in relation to the role of nutrition in health and disease. Finally, potential mechanisms by which development may be modified by early nutrition are considered.