Seventy-two 8-week-old ram lambs from three breeds, Suffolk, Soay and Friesland, were offered one of four diets based on dried grass and formulated to have a similar fatty acid content (60 g/kg DM) and containing: Megalac (high in 16 : 0, control; Volac Ltd, Royston, Herts., UK), whole linseed (18 : 3n-3), fish oil (20 : 5n-3 and 22 : 6n-3) or whole linseed plus fish oil. The lambs were slaughtered at approximately half of their mature live weight (43, 21 and 43 kg for Suffolk, Soay and Friesland lambs, respectively). Fish oil reduced DM intake and lamb live-weight gain (P<0·001), while DM intake, live-weight gain and subcutaneous fat content were highest in Suffolk and lowest in Soay lambs. Linseed feeding doubled the proportion (×100) of 18 : 3n-3 in the longissimus dorsi from 1·4 to 3·1 and in the subcutaneous adipose tissue from 1·2 to 2·6 (P<0·001). Suffolk and particularly Soay lambs contained higher proportions of 18 : 3n-3 than Friesland lambs in the longissimus dorsi, while in the adipose tissue, Suffolk lambs had the highest level. Feeding fish oil increased the muscle proportion (×100) of 20 : 5n-3 from 0·7 to 2·3 and 22 : 6n-3 from 0·3 to 0·8 (P<0·001). By contrast, the proportions of the longer-chain n-3 polyunsaturated fatty acids were similar across all three breeds. All three lipid supplements containing n-3 polyunsaturated fatty acids increased the content of muscle trans-18 : 1 relative to the control values, but conjugated linoleic acid (cis-9,trans-11–18 : 2) only increased in the muscle of lambs fed linseed. Feeding linseed or fish oil lowered the n-6 : n-3 ratio in sheep meat, but neither diet nor breed had much effect on the polyunsaturated fatty acid: saturated fatty acid ratio.

Obesity has reached epidemic proportions in many countries around the world. Because of the close relationship between obesity and type 2 diabetes, an epidemic of diabetes is close behind the obesity epidemic. Preventing and treating obesity is becoming an increasing priority. In the United States, over 60% of the adult population is overweight or obese and thus at increased risk of developing diabetes and cardiovascular disease. While the aetiology of obesity and diabetes is complex, diet clearly plays an important role both in the development and management of these diseases. There is interest in functional foods that could help in prevention and/or management of obesity and type 2 diabetes. This could involve food products that help management of ‘hunger’ or that increase ‘satiety’. It could also involve foods that contribute to more inefficient use of ingested energy (i.e. foods that stimulate energy expenditure more than would be expected from their energy content). As the concept of insulin sensitivity becomes generally more accepted by health care professionals and the public, foods may be targeted towards maximizing insulin sensitivity and towards ‘prevention’ of diabetes. In addition to foods that impact upon body weight, these may include foods that affect the glucose and/or insulin levels that are seen either following the ingestion of food or later in the day. The present paper reviews the complex aetiology of obesity and diabetes and considers a potential role for functional foods in prevention and treatment of obesity and diabetes.

Thirty growing yaks Bos grunniens or Poephagus grunniens, 1·0–3·5 years and 50–230kg, from their native altitudes (3000–4000m), were used to study the basal metabolism in this species and to evaluate the effects of high altitude and season on the energy metabolism. Fasting heat production (FHP) was measured at altitudes of 2260, 3250 and 4270m on the Tibetan plateau in both the summer and the winter, after a 90d adaptation period at each experimental site. Gas exchanges of the whole animals were determined continuously for 3d (4–5 times per d, 10–12 min each time) after a 96 h starvation period, using closed-circuit respiratory masks. Increasing altitude at similar ambient temperature (Ta) did not affect (P>0·10) FHP in the summer, but decreased (P<0·05) it at different Ta in the winter. However, the decrease of FHP in the winter was mainly due to the decrease of Ta instead of the increase of altitude. In the summer, the respiratory rate, heart rate and body temperature were unaffected by altitude, except for a decrease (P<0·05) in body temperature at 4270m; in the winter, they were decreased (P<0·05) by increasing altitude. In both seasons, the RER was decreased (P<0·05) by increasing altitude. At all altitudes for all groups, the daily FHP was higher (P<0·05) in the summer (Ta 6–24°C) than in the winter (Ta 0 to -30°C), and the Ta-corrected FHP averaged on 920 kJ/kg body weight0·52 at Ta 8–14°C and on 704 kJ/kg body weight0·52 at Ta -15°C respectively. We conclude that in the yak high altitude has no effect on the energy metabolism, whereas the cold ambient temperature has a significant depressing effect. The results confirm that the yak has an excellent adaptation to both high altitude and extremely cold environments.

The fasting concentration of non-esterified fatty acids (NEFA) and the degree to which it declines during an oral glucose tolerance test are closely associated with insulin resistance and glucose intolerance. However, relatively few studies have described possible environmental determinants of NEFA concentrations. Physical activity is likely to be related to NEFA levels, but habitual activity level is difficult to quantify in epidemiological studies. In particular, it is unclear whether NEFA is more closely related to cardio-respiratory fitness or to habitual energy expenditure. In order to quantify these relationships, we analysed data from the Ely prospective population-based study in which 931 subjects underwent a glucose tolerance test with measurements of cardio-respiratory fitness and 4 d energy expenditure by heart-rate monitoring, a technique previously validated against whole-body calorimetry and doubly-labelled water. In order to estimate the latent variables of usual fitness and energy expenditure, a subset of 190 subjects underwent repeat testing on three further occasions over 1 year. In analyses adjusting only for age and sex, energy expenditure and cardio-respiratory fitness were both negatively correlated with the total area under the NEFA curve following the oral glucose load (standardised β coefficients -0·030 and -0·039 respectively; both P<0·001) However, further adjustment for degree of obesity and bivariate measurement error suggested that the effect of energy expenditure was significantly greater than that for fitness (-0·047 and -0·005 respectively). These results suggest that the area under the NEFA curve in the oral glucose tolerance test, a measure of insulin sensitivity, is strongly associated with the habitual level of physical activity.

The aim of the present study was to compare variables of metabolism, physical activity and fitness to body composition in normal and overweight children in a cross-sectional study design. Body composition was assessed by anthropometric measurements and bioelectrical impedance analysis in forty-eight prepubertal children (age 5–11 years, thirteen normal-weight, thirty-five overweight). Total energy expenditure (EE) was measured by combination of indirect calorimetry (for measurement of resting EE) and individually calibrated 24 h heart-rate (HR) monitoring. Activity-related EE and physical activity level (PAL) were calculated. Time spent with min-by-min HR>FLEX HR was also used as a marker of moderate habitual and vigorous activities. Aerobic fitness (O2 pulse (O2 consumption:HR at submaximal steady-state heart rate), submaximal O2 consumption (VO2submaximal), RER at a HR of 170 beats per min) was determined by bicycle ergometry. Muscle strength of the legs (maximal isometric strength of musculus quadriceps and of musculus ischiocruralis (Fa max and Fb max respectively)) was measured by computer tensiometry. When compared with normal children, overweight children had higher skinfold thicknesses (sum of skinfold thicknesses at four sites +160%), fat mass (+142%), waist (+24%) and hip circumferences (+14%), resting EE (+13%) and RER (+5%). No significant group differences were found for fat-free mass, muscle mass, total EE, activity-related EE, PAL, HR>FLEX HR, VO2submaximal, O2 pulse, Fa max and Fb max as well as the fat-free mass- or muscle mass-adjusted values for resting EE, aerobic fitness and muscle strength. When compared with normal children, overweight children had a lower measured v. estimated resting EE (Δ resting EE) and spent more time watching television. There were positive relationships between fat-free mass(x) and resting EE(x), total EE(y), aerobic fitness(y) and muscle strength(y), but only Δ resting EE(x) and HR>FLEX HR(x) correlated with fat mass(y). In a stepwise multivariate regression analysis resting EE adjusted for fat-free mass and Δ resting EE were significant determinants of % fat mass and explained 29·7% of its variance. Thus, in the present cross-sectional study, resting EE was the most important determinant of fat mass.

The aim of the present study was to compare the differences in dietary and non-dietary factors contributing to normal weight and overweight among urban Chinese adults. Two cross-sectional population surveys were carried out in Tianjin, one of the largest cities in China. A total of 2631 subjects aged 25–64 years were selected by random stratified cluster sampling; 398 men and 490 women were overweight, and 886 men and 857 women were of normal weight. The diet was assessed by food weighing plus consecutive individual 3 d food records. Health-related behaviours and anthropometry were assessed. The overweight group had significantly higher mean daily intakes of energy and carbohydrate than the normal-weight group. Overweight men also had significantly higher mean daily intakes of protein and fat than normal-weight men. Age, daily intakes of energy and carbohydrate, and marital status were positively associated with overweight, while occupational and commuting physical activity, as well as smoking, were inversely associated with overweight among both genders. Daily intakes of protein, fat and alcohol were positively related to the incidence of being overweight among men. People with 7–12 years education were more likely to be overweight compared with those with less than 6 years of education. High intakes of energy and carbohydrate among both genders, as well as high intakes of protein and fat among men, and lower levels of occupational and commuting physical activity, being a non-smoker, and partly higher socio-economic status were related to a greater incidence of being overweight in this population.

The UK Food Standards Agency convened a group of expert scientists to review current research investigating the optimal dietary intake for n-9 cis-monounsaturated fatty acids (MUFA). The aim was to review the mechanisms underlying the reported beneficial effects of MUFA on CHD risk, and to establish priorities for future research. The issue of optimal MUFA intake is contingent upon optimal total fat intake; however, there is no consensus of opinion on what the optimal total fat intake should be. Thus, it was recommended that a large multi-centre study should look at the effects on CHD risk of MUFA replacement of saturated fatty acids in relation to varying total fat intakes; this study should be of sufficient size to take account of genetic variation, sex, physical activity and stage of life factors, as well as being of sufficient duration to account for adaptation to diets. Recommendations for studies investigating the mechanistic effects of MUFA were also made. Methods of manipulating the food chain to increase MUFA at the expense of saturated fatty acids were also discussed.

The papers in these proceedings truly reflect the wide nature of research work that is being undertaken and the advances that have been achieved particularly in the therapeutic application of probiotics. All abstracts are available as pdf and html format.

The effectiveness of a health and nutrition education programme, in changing certain chronic disease risk factors, was assessed after the 6 years intervention period was completed. The school-based intervention programme was applied to all children registered in the first grade (age 5·5–6·5 years) in 1992 in two counties of Crete, while the children from a third county served as a control group. In order to assess the effectiveness of the intervention, a variety of biological and behavioural parameters were measured before and following completion of the intervention in a randomly selected school-based sample of 602 intervention group (IG) and 444 control group (CG) pupils. At the end of the 6-year period, it was found that biochemical indices generally improved significantly more in the IG compared with the CG (mean change for IG v. CG was -0·27 v. -0·12 mmol/l for total cholesterol (TC); -0·07 v. +0·24 for TC:HDL and -0·13 v. +0·14 for LDL:HDL). Similarly, the changes observed in the anthropometric variables in the two groups were in favour of the IG (+3·68 v. +4·28 kg/m2 for BMI; +2·97 v. +4·47 mm for biceps skinfold). Total energy intake and consumption of total fat and saturated fat increased significantly less in the IG compared with the CG (+747·7 v. 1534·7 kJ (+178·7 v. +366·8 kcal); +5·9 v. +18·8 g and +0·8 v. +5·1 g respectively), while time devoted to leisure time physical activity and cardiovascular run test performance increased significantly more in the IG (+281 v. +174 min/week and +2·5 v. +1·2 stages respectively). The findings of the present study underline the importance of such programmes in health promotion and disease prevention. Although the long-term effects of these programmes can only be assessed by tracking this population through to adolescence and adulthood, these programmes seem to have the potential to lead to a healthier lifestyle and thus a reduction in risk factor levels.

A nutritional survey based on twelve adolescent male Kalenjin runners in Kenya during a 2-week field study was carried out in order to determine the composition of their diet and make a comparison with macronutrient recommendations for athletes. Food samples were collected for analysis of macronutrient distribution and energy content from main meals and the macronutrient distribution and energy content of additional food intake were based on the information of a 24 h recall interview and estimated from food tables. The diet of the Kalenjin runners was very high in carbohydrate (71 % 8·7 g/kg body weight per d) and very low in fat (15 %). Intake of total protein (13 %; 1·6 g/kg body weight per d) was above the daily intake recommended by the Food and Agriculture Organization/World Health Organization/United Nations University (FAO/WHO/UNU), while essential amino acid intake was estimated to be in the borderline-to-low range based on FAO/WHO/UNU recommendations for children <12 years and adults. The energy intake was mainly derived from vegetable sources (90 %) with maize and kidney beans as the staple food (81 %). The diet of the Kalenjin runners met recommendations for endurance athletes for total protein and most essential amino acid intake as well as carbohydrate intake even though it was based on a small range of food items.

One of the most promising areas for the development of functional foods lies in modification of the activity of the gastrointestinal tract by use of probiotics, prebiotics and synbiotics. While a myriad of healthful effects have been attributed to the probiotic lactic acid bacteria, perhaps the most controversial remains that of anticancer activity. However, it must be emphasised that, to date, there is no direct experimental evidence for cancer suppression in man as a result of consumption of lactic cultures in fermented or unfermented dairy products, although there is a wealth of indirect evidence, based largely on laboratory studies. Presently, there are a large number of biomarkers available for assessing colon cancer risk in dietary intervention studies, which are validated to varying degrees. These include colonic mucosal markers, faecal water markers and immunological markers. Overwhelming evidence from epidemiological, in vivo, in vitro and clinical trial data indicates that a plant-based diet can reduce the risk of chronic disease, particularly cancer. It is now clear that there are components in a plant-based diet other than traditional nutrients that can reduce cancer risk. More than a dozen classes of these biologically active plant chemicals, now known as ‘phytochemicals’, have been identified. Although the vast number of naturally occurring health-enhancing substances appear to be of plant origin, there are a number of physiologically active components in animal products (such as the probiotics referred to above) that deserve attention for their potential role in cancer prevention.

Using controlled in vivo and in vitro pharmacological methods, we evaluated the safety of papaya (Carica papaya) consumption in pregnancy with reference to its common avoidance during pregnancy in some parts of Asia. Ripe papaya (Carica papaya L. (Caricaecae) blend (500 ml/l water) was freely given to four groups of Sprague-Dawley rats at different stages of gestation (days 1–5, 6–11, 12–17 and 1–20). The control group received water. The effect of ripe papaya juice and crude papaya latex on pregnant and non-pregnant rats' uteri was also evaluated using standard isolated-organ-bath methods. The daily volumes (ml) of ripe papaya blend consumed by the treated group were significantly (P<0·05) more than water consumed by the control (control 40·3 (<FONT SIZE="-2">SD</FONT> 11·6) v. treated 64 (SD 19·0)). There was no significant difference in the number of implantation sites and viable fetuses in the rats given ripe papaya relative to the control. No sign of fetal or maternal toxicity was observed in all the groups. In the in vitro study, ripe papaya juice (0·1–0·8 ml) did not show any significant contractile effect on uterine smooth muscles isolated from pregnant and non-pregnant rats; conversely, crude papaya latex (0·1–3·2 mg/ml) induced spasmodic contraction of the uterine muscles similar to oxytocin (1–64 mU/ml) and prostaglandin F2α (0·028–1·81 μM). The response of the isolated rat uterine smooth muscles to 0·2 mg crude papaya latex/ml was comparable to 0·23 μM prostaglandin F2α and 32 mU oxytocin/ml. In the 18–19 d pregnant rat uterus, the contractile effect of crude papaya latex was characterized by tetanic spasms. The results of the present study suggest that normal consumption of ripe papaya during pregnancy may not pose any significant danger. However, the unripe or semi-ripe papaya (which contains high concentration of the latex that produces marked uterine contractions) could be unsafe in pregnancy. Though evaluation of potentially toxic agents often relies on animal experimental results to predict risk in man, further studies will be necessary to ascertain the ultimate risk of unripe papaya–semi-ripe papaya consumption during pregnancy in man.

Serum ferritin, serum vitamin B12, erythrocyte folate, plasma vitamin C and plasma 25-hydroxycholecalciferol levels were measured in 208 men and 197 women, >75 years old and living in the community, in order to assess micronutrient status. Anthropometric measurements (height, weight, demispan and mid-upper arm circumference) were made and a 114-item questionnaire covering a wide range of health and diet-related topics was administered by an interviewer. Only 4% of subjects had a BMI <20, but the prevalence of marginal deficiency of the micronutrients ranged from 7% for Fe to 47% for vitamin D. There was no association between low micronutrient status (defined as being in the lowest third of the distribution of micronutrient status) and having BMI or mid-upper arm circumference in the lowest third of the distribution for any of the nutrients. Leaving food on the plate was strongly associated with both low Fe status and low vitamin D status. Having breakfast cereal less than once per week was strongly associated with low folate status, while having fresh fruit juice less than once per week, having had less than two portions of fruits and vegetables the previous day and believing that food is not important for health were strongly associated with low vitamin C status. Low vitamin D status was strongly associated with a wide range of general health and disability measures. Having a weekly household income of less than £150 was associated with low status of Fe, folate, vitamin C and vitamin D.

The increasing prevalence of obesity in the USA, especially among minority populations, is a serious public health concern. This present study analysed repeated measurements at baseline and at 6 and 12 months on 351 women in the control group and 575 women in the intervention group of the Women's Health Trial: Feasibility Study in Minority Populations. Dynamic random effects models were estimated using the three repeated observations to explain the effects of energy and macronutrient intakes, physical exercise, unhealthy eating habits and socio-economic characteristics on the subjects' body weights and waist and hip circumferences. In both the control and intervention groups, physical exercise was negatively associated with body weight and with waist and hip circumferences, while an index of unhealthy eating habits was positively associated (P<0·05). The proportion of energy derived from carbohydrate and from saturated and monounsaturated fat were often significant predictors of body weight and of waist and hip circumferences in the two groups. The results indicated that nutrition education programmes for improving eating habits and increasing physical exercise can reduce obesity prevalence in the USA.

The Tanita TBF-305 (Tanita Corp., Tokyo, Japan) is a commercially available foot-to-foot bioelectrical impedance analysis (BIA) system. The manufacturer-supplied equations incorporate gender, mass, height, activity category and a measured impedance value to determine % body fat (BF). The purpose of the present study was to determine whether the manufacturer-supplied ‘adult’ and ‘athlete’ equations provided an accurate estimate of % BF for a group of young men with varying activity levels. Fifty-seven men (18–35 years old) were categorized into the following groups: (1) highly active (HA) (≥10·0 h aerobic activity/week); (2) moderately active (MA) (2·5–10·0 h aerobic activity/week); (3) less active (LA) (<2·5 h aerobic activity/week). The % BF was measured using the BIA ‘athlete’ and ‘adult’ modes. After BIA measurements, residual volume was measured and hydrostatic weighing (HW) was performed. The amount of activity performed by each group was significantly different (P<0·001). No significant differences were found between the % BF determined by the ‘athlete’ mode and HW for HA (P=0·309) and MA (P=0·091). However, a significant difference was found for LA (P=0·001). The % BF determined by the ‘adult’ mode and HW was not different for LA (P=0·395), but was significantly different for MA (P<0·001) and HA (P<0·001). The choice of activity mode on the foot-to-foot BIA significantly alters prediction of % BF. With careful selection of activity mode, there was no statistical difference between % BF determined by HW and the BIA, but the range of individual error scores was large.

Only a few reports exist of plasma amino acid profiles in the oldest-old, and none exist of the oldest-old with cognitive problems. Therefore, we measured fasting plasma amino acid concentrations in twenty-three healthy community-dwellers aged 90–103 years (group A); eighteen community-dwellers with mild cognitive impairment without dementia aged 91–104 years (group B); thirty-three patients with dementia aged 96–100 years (group C); and sixty healthy young controls aged 20–50 years. Biochemical and anthropometric parameters, and the basic activities of daily living (ADL) were also measured. Independent of cognitive status, in all oldest-old groups, essential:non essential amino acids (EAA:NEAA) was lower than in young controls and positively associated with body muscle mass. Patients with dementia were further characterized by a negative association between EAA:NEAA and the number of dependent ADL. All oldest-old groups had higher values of tyrosine:other large neutral amino acids (LNAA) than young controls. Groups B and C also had a higher phenylalanine:other LNAA. These data show that abnormalities in plasma amino acid profile are common in oldest-old individuals independent of their cognitive status, but that, in oldest-old patients with dementia, they are associated with functional disability. The abnormalities in phenylalanine and tyrosine plasma availability could contribute to the cause or aggravation of concurrent cognitive problems because these amino acids are neurotransmitter precursors and compete with other LNAA for transport into the brain.

Osteoporosis is a growing global problem. The health care costs and decreased productivity and quality of life are staggering. Much research is invested in life-style approaches to build peak bone mass during growth to prevent osteoporosis as well as to treat the disease in later life. Functional foods have enjoyed a niche in bone health. Foods fortified with Ca are most popular. Other bone nutrients such as vitamin D, Mg and vitamin K are sometimes added. Future products are likely to include enhancers of Ca absorption such as inulin or whey proteins. Dietary factors that reduce urinary Ca loss (plant proteins) or suppress bone resorption (possibly phyto-oestrogens) are also gaining attention. Methodologies for evaluating the effectiveness of functional foods on bone health include measures of bone quality such as bone densitometry or measures of Ca metabolism, particularly absorption. Biochemical markers for bone turnover are less satisfactory for diet-related effects. Use of a rare isotope, 41Ca, and accelerator mass spectrometry offers a new approach for assessing the ability of functional foods to suppress bone resorption.

This study estimated total body water (TBW) in four groups (twelve per group; sedentary and highly trained men and women) at the time of 2H dosing (T0) and after a 3·5 h equilibration period (Teq). Standard TBW calculations were employed at T0 (no correction for disproportionate urinary tracer loss) and Teq (correction for urinary tracer loss only), plus those calculations that corrected for a disproportionate urinary tracer loss and insensible tracer loss respectively. The measurement of body density enabled the four TBW estimates to be compared for the determination of three-compartment % body fat (BF). The very small difference between the standard and corrected T0 TBW data was not significant (P=0·914) and no Group×TBW interaction was identified (P=0·125). These results reflect the closeness of the 2H concentration in the urine produced during the equilibration period and the Teq saliva samples. The associated mean % BF values were essentially identical. Although correcting for insensible 2H losses in addition to urinary losses at Teq produced a statistically significant (P<0·001) lower mean TBW (about 200 g) than the standard calculation, this translated to a small difference in % BF (0·3). The larger difference (about 500 g, P<0·001) between the two (T0, Teq) corrected TBW calculations was also associated with a small body composition difference (0·1 % BF), which was less than the propagated error (0·3 % BF) for the three-compartment body composition model. Corrections to the standard calculations of TBW at T0 and Teq for a protocol employing a brief equilibration period (3·5 h) were therefore of marginal use for improving the accuracy of % BF estimates. The TBW difference over time (T0v. Teq) also had little impact on % BF values.