In pre-industrial times, honey was the main source of concentrated sweetness in the diets of many peoples. There are no precise figures for per capita consumption during most periods in history because honey was part of either a hunter-gatherer or subsistence economy. Until now, historians and food writers have proposed that it was a scarce commodity available only to a wealthy few. We do know, however, that in a cash economy honey was sold in large units (gallons and even barrels) and it was present in such abundance that mead, made from honey, was a common alcoholic drink. A reappraisal of the evidence from the Stone Age, Antiquity, the Middle Ages and early Modern times suggests that ordinary people ate much larger quantities of honey than has previously been acknowledged. Intakes at various times during history may well have rivalled our current consumption of refined sugar. There are implications therefore for the role of sugar in modern diets. Refined sugar may not have displaced more nutrient-rich items from our present-day diets but only the nutritionally comparable food, honey.

The aim of the work was to compare the faecal output and digestibility estimated by two mathematical approaches with the actual amount of faeces excreted or feed digested by Siental cows. Experimental data (intakes and digestibility measured over 5 d) and faecal Cr concentrations (measured at 0, 4, 8, 12, 16, 24, 32, 48, 56, 72, 96, 120 and 144 h after a pulse dose of Cr-mordanted forage) were collected from published experiments and fitted to a multicompartmental (MC) model and a γ age-dependent (AD) model. From a statistical point of view, the MC model was very satisfactory while the AD model produced lower r2 and higher SE values and reached satisfactory statistical values only for higher DM intakes (lactating animals). The MC model produced higher correlations with the digestibility values while the AD model generated better correlations with the intake data; DM intake and digestibilities were more highly correlated with the model's parameters than neutral-detergent fibre terms. The regression between the estimated faecal outputs obtained with the two models showed an intercept closeto 0 (P>0·05) and angular coefficients near 1; there was a good correspondence of the estimates especially for the lowest values of output. The r2 values of the regressions were 0·800 and 0·829 for the MC and AD models respectively and their SE were 2·93 and 2·63. The ability of the two models to predict faecal output and digestibility was very similar, independent of the statistical accuracy of fitting the Cr- concentration data. The results indicate that variation of Cr concentration is the result of the entire digestive process, i.e. dilution and passage, which interact in a competitive or associative way.

There is a lack of information concerning the diet of vegetarian children. The present study compared the dietary intake of fifty vegetarian children, aged 7–11 years, with fifty matched omnivores. Three 3 d food records were completed by each child at intervals of 6 months. The day after completing the record each child was interviewed to clarify food items and assess portion sizes. Food records were analysed using Microdiet (University of Salford). Finger-prick cholesterol and haemoglobin measurements were taken from a subsample of the group. Only one child's family was a member of the Vegetarian Society and almost one-third of vegetarian children had omnivorous parents (seventeen of fifty subjects). The energy intake (MJ) of the vegetarians was significantly lower than that of the omnivores, 7·6 (SD 1·05) and 8·0 (SD 1·36) respectively; there were no significant differences in Fe or fat intakes. For the vegetarians polyunsatnrated:saturated fat ratio (P:S 0·7 (SD 0·04)) and NSP intake (13·8 (SD 0·7) g/d) were significantly higher than those of the omnivores (P:S 0·5 (SD 0·02), NSP 10·3 (SD 0·4) g/d). There was no significant difference in cholesterol measurements (mmol/I) between the two groups: vegetarian 3·5 (SD 0·12), omnivores 3·7 (SD 0·15). The haemoglobin level (g/I) of the vegetarians (11·8 (SD 0·2)) was significantly below that of the omnivores (12·4 (SD 0·2)); 47·5% of the vegetarian children fell below the third percentile of the Dallman reference curves (Dallman & Siimes, 1979). The intake of the vegetarians more closely resembled current recommendations (Department of Health, 1991), although they need to be as aware as omnivores of the need to reduce fat intake. The haemoglobin levels of vegetarian children suggest that they need dietary advice to ensure optimal absorption of Fe.

The objective of the present study was to determine the effect of replacement of fat by sucrose polyester (SPE) within a lunch or evening meal on subsequent energy intake and appetite control. The 2 × 2 design was intended to examine the effect on appetite of reducing the total energy and fat content of a meal (lunch or dinner) by replacement of natural fat with 55 g SPE. The effects were monitored by measuring motivation to eat or actual food consumption during the remainder of the test day (day 1) and throughout the following day (day 2). The 2 × 2 design yielded four conditions which were a control meal (5192 kJ, 73·2 g fat) and a fat-replaced meal (3305 kJ, 54·6 g SPE, 24 g fat) at midday (lunch) or in the early evening (dinner). No significant differences were seen in ad lib. energy intake after the test meals on day 1 or day 2. Certain differences were detected in fat intake on day 2 but these did not suggest nutrient compensation in response to the fat replacement. Subjective assessment of motivation to eat did not indicate that the fat-reduced meal had a weaker satiating efficiency than the control meal. A reduction in fat content, using fat replacement, did not reduce the satiating efficiency of a test meal given at lunch or dinner. No energy or macronutrient compensation occurred following the reduction in energy or fat intake during the rest of the test day or during the whole of the next day.

The cholesterolaemic effects in rats of a diet (VS) containing Bambara groundnuts (Vignu subterrunea), a popular legume eaten in Nigeria, were compared with diets PV, PS, LC and PL, containing baked beans (Phaseolus vulgaris), marrowfat peas (Pisum sativum), lentils (Lens culinaris Medik.) and butter beans (Phaseolus lunatus) respectively. Sixty Sprague-Dawley rats were fed on hypercholesterolaemic semi-purified diets supplemented with 10 g cholesterol and 5 g cholic acid/kg and formulated to provide 40% of energy from fat, as in a typical Western-type human diet. Legumes were substituted for 330 g/kg of the semi-purified diet on a dry-matter basis, which was modified to maintain the same contribution of energy sources as the control diet C3. Another ten rats were fed on control diet C2, which was similar to diet C3 but with no added cholesterol. The rats were fed for 8 weeks and plasma cholesterol levels were measured at weeks 4 and 8. The diets incorporating the five different legume species produced very Merent cholesterolaemic effects. Diets PV and PL were more potent at lowering raised plasma cholesterol levels than diets PS and LC. Inclusion of the Bambara groundnut into the semi-purified diet resulted in an exaggeration of hypercholesterolaemia. Differences in cholesterol-lowering capacity of the various legume diets in this experiment could not be related to concentrations of faecal bile acids or neutral sterols. However, there was evidence that the inclusion of legumes in the diets reduced the faecal excretion of secondary bile acids

Indian River male broiler chickens growing from 7 to 30 d of age were fed on diets containing crude protein levels ranging from 120 to 3041 g/kg plus 0 or 1 mg triiodothyronine (T3/)kg diet. The purpose of this study was to examine the effects of these treatments on lipogenesis after a common diet was fed (180 g crude protein/kg diet from 30 to 56 d of age). Dietary treatment groups were sampled at 30 and 56 d. In vitro lipogenesis was determined by incubating liver explants for 2h at 37°in Hanks' salts containing 25 mM-HEPES and 10 mM-[2-14C]acetate and then measuring acetate incorporation into total lipid. Growth and feedconsumption from 7 to 30 d increased (P<0·01) as dietary protein increased from 120 to 210 g/kg diet. Both measurements decreased as crude protein increased from 210 to 300 g/kg diet.T, decreased (P<0·01) growth and feed intake during this period.Low-protein (<180 g/kg) diets increased (P<0·05) and T3, decreased lipogenesis in 30-d-old chickens. Although birds given T3from 7 to 30 dgrew at the greatest rate from 30 to 56 d of age, the final body weight was still less than controls.In vifm lipogenesis at 56 d of age was not affected by either of the two dietary treatments. In contrast, the relative size of the abdominal fat pad (g/kg body weight) at 56 d was decreased by feeding T3from 7 to 30 d. Any changes in metabolism elicited by either dietary protein levels or hormone treatments may be specific to the particular dosing interval and are not sustained when acommon diet is fed during a repletion period.

Whole-body fatty acid analysis in rats has previously shown that 50–70% of dietary linoleate and α-linolenate is β-oxidized to CO2 and that this value increases with refeeding after a single episode of fasting. Our hypothesis was that repeated fasting-refeeding or weight-cycling would increase the β-oxidation of linoleate and α-linolenate thereby depleting their whole-body levels. In rats consuming 3% energy as linoleate and 0·15 % energy as α-linolenate during a 16 d balance period, 19% of the linoleate consumed accumulated in weight-cycled rats compared with 34% in the free-fed controls (P < 0.01). Similarly, 11% of the α-linolenate consumed accumulated in the weight-cycled rats compared with 22% in the controls (P < 0.01). Arachidonate and docosahexaenoate also accumulated to lower extents in the weight-cycled rats than in the controls. In contrast, whole-body accumulation of palmitate, stearate and oleate was not different between the weight-cycled group and the controls when measured as a proportion of intake or relative to weight gain. Thus, whole-body depletion of linoleate and α-linolenate did not occurper se but the partitioning of linoleate and α-linolenate was significantly altered by weight-cycling resulting in lower whole-body accumulation and higher apparent oxidation of all polyunsaturates especially linoleate and α-linolenate.

There is a paucity of information on the metabolic effects of undernutrition of the ewe carrying multiple fetuses in late pregnancy. In the present study the effects of induction of ketosis from 132 d gestation in ewes carrying twin fetuses were compared with a control group. The ewes were well fed up to 132 d. Ketotic ewes showed a loss of condition score from 3·7 (SE 0·11) at 130 d gestation to 3·0 (SE 0·15) 10 d later after clinical recovery, compared with control twin-pregnant ewes (P < 0·01). The weight loss during the same time period was from 70·6 (SE 2·7) kg at 130 d to 64·2 (SE 2·7) kg at 140 d gestation. As expected, both groups lost weight and condition score in the first 28 d of lactation. Induction of ketosis caused a significant shortening of the gestation period to 142·8 (SE 0·7) d compared with 150 (SE 0·4) d in normal twin-pregnant ewes (P < 0·001). Ewes with induced ketosis recovered clinically and showed a normal feed intake by 3·4 (SE 0·07) d; three required treatment. Induction of ketosis resulted in reduction of hepatic uptake of bromosulphthalein (P < 0·01) and its biliary excretion (P < 0·05), metabolic clearance rate (P < 0·001), fractional clearance (P < 0·001) and 15 and 30 min retention compared with control twin-pregnant ewes. Most values had returned to normal by the first week of lactation. It is thought that in human pregnancy similar changes in bromosulphthalein clearance may be related to reduced binding sites for bromosulphthalein in the liver caused by increased circulating oestrogens. Induction of ketosis resulted in a significant hypoglycaemic (P < 0·01), ketotic (P < 0·001) state compared with well-fed twin-pregnant ewes. These changes could be correlated with the severity of the clinical signs, together with a significant rise in plasma urea (P < 0·001) and NH3 (P < 0·05) concentrations. Again, the return of most of these values to normal by the first week of lactation lends support to the reversibility of hepatic lesions caused by fatty infiltration of the liver. The seventy of this condition in naturally occurring cases suggests that factors other than undernutrition may be contributory, such as the general body condition of the ewe and glucose metabolism by the liver, including the conversion of propionate to glucose.

The influence of different protein sources on Zn absorption was evaluated in healthy adults by radioisotopic labelling of single meals, followed by whole-body retention measurements 14 d after intake. Semi-synthetic liquid diets were used for the evaluation of different animal-protein sources and dephytinized soyabean-protein isolate ( ··01 g phytic acid/kg). Zn absorption was measured in the same subjects from identical test meals containing no added protein. No statistically significant differences were found in the Zn absorption from test meals containing bovine whey, casein or egg albumen when compared with test meals without added protein. Bovine serum albumin (BSA) and soyabean-protein isolate (< ··01 g phytic acid/kg) significantly reduced the mean absorption of Zn from 45–49% (no added protein) to 38·0 (SD 10·9) (BSA, P < ··05) and 33·9 (SD 12·6)% (soyabean-protein isolate < ··01 g phytic acid/kg, P < ··01). These results demonstrate that Zn absorption is inhibited by certain protein sources, such as BSA and dephytinized soyabean-protein isolate, while other proteins have little or no effect.

Using streptozotocin-induced diabetic Wistar rats, studies were carried out to examine the metabolic availability of vitamin A in the plasma, liver and the retina of the eye. Control and diabetic rats were fed ad lib. on a semi-purified diet either with or without (basal) vitamin A supplementation, or pair-fed on the basal diet for 4 weeks. Despite the fact that diabeticrats consumed 48% more feed, they had lower plasma concentrations of retinol (P<0·003). The decrease in plasma retinol concentration was a response to diabetes (or diabetes-induced trauma), since neither pair-feeding (P<0·01) nor vitamin A supplementation altered this effect (P<0·05). Furthermore, the hepatic concentrations of the vitamin in these animals remained elevated and this increase was greater in the supplemented diabetic group (P<0·001). Decreases in 11-cis retinal (a component of rhodopsin) concentrations in the retina were also observed in diabetic animals. The increased hepatic and the decreased plasma and retina vitamin Alevels suggest a defect in the transport of the vitamin from the liver.

Studies with anaemic children and pregnant women from areas where vitamin A deficiency is endemic have shown a beneficial effect on Fe status of supplemental vitamin A in addition to Fe supplementation. This suggests a relationship between vitamin Aand Fe status, which we attempted to mimic in rats with anaemia and chronic vitaminA deficiency. Male rats were fed on Fe-adequate diets (35 mg Fe/kg)containing different levels of vitamin A (1200,450,150,75 and 0 retinol equivalents (RE)/kg feed) until they were 5 weeks old. These diets wereidentical to the diets fed to their mothers. Then the young male rats were transferred to diets containing the same levels of vitamin A but no added Fe. After another 2 weeks the rats wererepleted with Fe (35 mg/kg feed) without or with vitamin A to a level of 1200 RE/kg feed. Increased vitamin A intake by the groups previously fed on diets with either 0 or 75 RE/kg produced a reduction in blood haemoglobin concentration, packed cell volume and erythrocyte count. In the group which had been fed on the diet without vitamin A, supplemental vitamin A raised mean cell volume, plasma Fe concentration and total Fe-binding capacity. Vitamin A supplementation during the period of Fe repletion produceda decrease in splenic and tibia Fe concentration, the effect being greater with increasing seventy of previous vitamin A deficiency. The paradoxical effect of supplemental vitamin A on haemoglobin, packed cell volume and erythrocyte count can be explained by a decrease in the degree of haemwoncentration. Thus, the positive effect of supplemental vitamin A seen in humans is also observed with rats under controlled experimental conditions. We speculate that supplemental vitamin A during Fe repletion contributes to optimum erythropoiesis and Fe mobilization when baseline vitamin A status is impaired

To study the effect on plasma 25-hydroxycholecalciferol (25(OH)D), 1,25-dihydroxycholecalciferol (1,25(OH)2D) and parathyroid hormone (PTH) we supplemented premenopausal (aged 30 (SD 7) years) and postmenopausal (aged 61 (SD 2) years) white women living in The Netherlands in late winter/early spring, and elderly black and white women (aged 75 (SD 6) years) living in Curacao (Dutch Antilles) with either 10 or 20µpg cholecalciferol/d for 4, 5 and 9 weeks respectively. Baseline plasma 25(OH)D concentration of Dutch women was lower than that of Curacao women. Postmenopausal Dutch women had a higher PTH concentration in plasma than premenopausal Dutch and postmenopausal Curaçao women. There were no differences in plasma 1,25(OH)2D. Cholecalciferol administration increased 25(OH)D in all groups, 1,25(OH)2D in postmenopausal Curaçao women and PTH in postmenopausal Curaçao women and premenopausal Dutch women. Serum and urinary Ca and phosphate concentrations did not change. There were no response differences between 10 and 20 µg doses. Oral cholecalciferol administration (either 10 or 20 µg/d) to women living at northern latitudes in late winter/early spring increased 25(OH)D levels to the baseline levels of elderly people living in the tropics.