The effect of eicosapentaenoic acid on rat lymphocyte proliferation depends upon its position in dietary triacylglycerols.

Animal and human studies have shown that greatly increasing the amount of fish oil [rich in long-chain (n-3) PUFA] in the diet can decrease lymphocyte functions. The effects of a more modest provision of long-chain (n-3) PUFA and whether eicosapentaenoic acid (20:5) and docosahexaenoic acid (22:6) have the same effects as one another are unclear. Whether the position of 20:5 or 22:6 in dietary triacylglycerols (TAG) influences their incorporation into immune cells and their subsequent functional effects is not known. In this study, male weanling rats were fed for 6 wk one of 9 diets that contained 178 g lipid/kg and that differed in the type of (n-3) PUFA and in the position of these in dietary TAG. The control diet contained 4.4 g alpha-linolenic acid (18:3)/100 g total fatty acids. In the other diets, 20:5 or 22:6 replaced a portion (50 or 100%) of 18:3, and were in the sn-2 or the sn-1(3) position of dietary TAG. There were significant dose-dependent increases in the proportion of 20:5 or 22:6 in spleen mononuclear cell phospholipids when 20:5 or 22:6 was fed. These increases were at the expense of arachidonic acid and were largely independent of the position of 20:5 or 22:6 in dietary TAG. Spleen lymphocyte proliferation increased dose dependently when 20:5 was fed in the sn-1(3) position of dietary TAG. There were no significant differences in interleukin-2, interferon-gamma or interleukin-10 production among spleen cells from rats fed the different diets. Prostaglandin E(2) production by spleen mononuclear cells was decreased by inclusion of either 20:5 or 22:6 in the diet in the sn-1(3) position. Thus, incorporation of 20:5 or 22:6 into spleen mononuclear cell phospholipids is not influenced by the position in dietary TAG. However, the pattern of incorporation may be influenced, and there are some differential functional effects of the position of long-chain (n-3) PUFA in dietary TAG. A moderate increase in the intake of 20:5 at the sn-1(3) position of dietary TAG increases lymphocyte proliferation.

Effect of geometric field of view on stereoscopic spatial judgments.

Within a stereoscopic display the field of view (FOV) was held constant at 13.86 degrees while the geometric field of view (GFOV) was varied across four levels: 0 degrees (parallel), 13.86 degrees (veridical), 50 degrees and 100 degrees. Participants performed a distance-matching task where they adjusted the distance of a standard track from the centre of the display to match the distance of a target track from the same point. The results indicated that while the least error occurred in the veridical GFOV condition, small variations of GFOV away from the veridical have little effect. Large differences between FOV and GFOV (36 degrees and 86 degrees) increased errors markedly. A trend toward better performance in the veridical GFOV condition relative to the parallel GFOV condition suggests that the use of linear perspective information in a stereoscopic display may facilitate more accurate spatial perception. Actual or potential applications of this work include stereoscopic display design in aviation and non-aviation settings.

The effects of stimulus set size and word frequency on verbal serial recall.

Two experiments are reported which examine immediate serial recall for high- and low-frequency words. The words in each list were either repeatedly drawn from the same small pool of candidates (in the closed set conditions) or each word only ever occurred once during the experiment (in the open set conditions). The results consistently show an effect of word frequency but the effect of set size was only apparent for low-frequency words. It is argued that both frequency and set size effects reflect processes concerning the "clean-up" of degraded short-term memory traces.

The acute physiological and mood effects of tea and coffee: the role of caffeine level.

The objective of this study was to determine the effect of caffeine level in tea and coffee on acute physiological responses and mood. Randomised full crossover design in subjects after overnight caffeine abstention was studied. In study 1 (n = 17) the caffeine level was manipulated naturalistically by preparing tea and coffee at different strengths (1 or 2 cups equivalent). Caffeine levels were 37.5 and 75 mg in tea, 75 and 150 mg in coffee, with water and no-drink controls. In study 2 (n = 15) caffeine level alone was manipulated (water, decaffeinated tea, plus 0, 25, 50, 100, and 200 mg caffeine). Beverage volume and temperature (55 degrees C) were constant. SBP, DBP, heart rate, skin temperature, skin conductance, and mood were monitored over each 3-h study session. In study 1, tea and coffee produced mild autonomic stimulation and an elevation in mood. There were no effects of tea vs. coffee or caffeine dose, despite a fourfold variation in the latter. Increasing beverage strength was associated with greater increases in DBP and energetic arousal. In study 2, caffeinated beverages increased SBP, DBP, and skin conductance and lowered heart rate and skin temperature compared to water. Significant dose-response relationships to caffeine were seen only for SBP, heart rate, and skin temperature. There were significant effects of caffeine on energetic arousal but no consistent dose-response effects. Caffeinated beverages acutely stimulate the autonomic nervous system and increase alertness. Although caffeine can exert dose-dependent effects on a number of acute autonomic responses, caffeine level is not an important factor. Factors besides caffeine may contribute to these acute effects.

Use of structured triacylglycerols containing predominantly stearic and oleic acids to probe early events in metabolic processing of dietary fat.

Early events in the metabolic processing of dietary triacylglycerol may have an important impact on subsequent development of risk factors for coronary heart disease. We have used structured triacylglycerols containing predominantly stearic or oleic acids at the sn -2 position to probe aspects of the processing of dietary fatty acids presented to adipose tissue in chylomicron-triacylglycerol. Studies were conducted on 14 healthy women who were given meals containing 85 g carbohydrate and 60 g of either of the two structured triacylglycerols in random order. Systemic concentrations and arterio-venous differences across adipose tissue for plasma triacylglycerol and non-esterified fatty acids were measured, together with analysis of the fatty acid composition of the relevant fractions. The stereo-specific structure of the ingested triacylglycerol was largely preserved in chylomicron-triacylglycerol. Systemic concentrations of total and individual non-esterified fatty acids were not significantly different after ingestion of the two fats, nor were their rates of release across adipose tissue. The composition of non-esterified fatty acids released from adipose tissue changed after the meal to reflect more closely the composition of the triacylglycerol ingested, but again no significant differences were observed between the two test meals. There was no detectable release of monoacylglycerol from adipose tissue after either test meal. We conclude that the environment for lipoprotein lipase action in adipose tissue in vivo is likely to be highly organized, such that there is no release of monoacylglycerol, nor preferential uptake or release of fatty acids from chylomicron-triacylglycerol according to the nature or the position within triacylglycerol of the fatty acid.

Double-blind, randomized trial of a synthetic triacylglycerol in formula-fed term infants: effects on stool biochemistry, stool characteristics, and bone mineralization.

BACKGROUND: The low sn-2 palmitate content of infant formulas results in formation of fatty acid calcium soaps in the stools and reduced calcium absorption. OBJECTIVE: Our objective was to test the hypotheses that increasing the proportion of sn-2 palmitate in formula for term infants would result in greater skeletal mineral deposition and reduced stool hardness. DESIGN: Healthy term neonates were randomly assigned to receive standard formula (n = 103) or formula containing 50% sn-2 palmitate (high-sn-2 formula; n = 100) for 12 wk. One hundred twenty breast-fed infants were also studied. The main outcome measures were 1) radial (single-photon absorptiometry) and whole-body (dual-energy X-ray absorptiometry) bone mineral content (WBBMC) at 12 wk and 2) stool frequency, volume, and consistency at 6 and 12 wk. Secondary outcome measures included stool fatty acid content. RESULTS: Infants receiving high-sn-2 formula had higher WBBMC (128.1 +/- 9.7 compared with 122.7 +/- 10.1 g, adjusted for size and sex), softer stools at 6 and 12 wk, and a lower proportion of stool soap fatty acids than did infants receiving the control formula. Breast-fed infants had adjusted WBBMC values (128.3 +/- 9.1 g) similar to those of infants fed high-sn-2 formula and significantly higher than those of infants fed the control formula. CONCLUSIONS: Changing the stereoisomeric structure of palmitate in infant formula resulted in higher WBBMC, reduced stool soap fatty acids, and softer stools more like those of breast-fed infants. The greater bone mass measured could be important if it persists beyond the trial period; this merits further investigation.

Sequential effects in rudimentary auditory and visual tasks.

Three experiments examined sequential effects in choice reaction time tasks. On each trial, a right/left positional judgment was made to a either a pure tone or a luminance increment in a visual array of box elements. In the first two experiments, a preparatory signal was presented prior to each imperative signal to indicate the relevant stimulus modality. At a short stimulus onset asynchrony (SOA) between the preparatory and the imperative signal (i.e., 60 msec), subjects were quicker to repeat the same response than to change their response when presented with successive tones, although no such repetition effect occurred on the visual target trials. Subjects were impaired if the stimulus modality changed across successive trials regardless of the modality of the target. At a longer SOA (i.e., 500 msec), these sequential effects were abolished; subjects were assumed to be able to prepare for the relevant modality because of the presentation of the preparatory signal. When the preparatory signals were omitted, in a final experiment, the modality-switching costs were still evident, but now inhibition of return occurred on both the auditory and the visual target trials-subjects were now impaired in responding when the target reappeared at its immediately previous location. It seems, therefore, that the repetition effect and modality-switching effects do dissociate. The data revealed clear differences between orienting attention to a particular spatial locale and focusing attention to a particular sensory modality.

Sequential effects in auditory choice reaction time tasks.

This paper concerns sequential effects in choice reaction time tasks. Performance in two interleaved auditory tasks was examined, and two general types of sequential effects were revealed. First, a response repetition effect occurred: Subjects were facilitated in responding when both the stimulus and the response were immediately repeated. Generally, it appeared that subjects were operating according to the bypass rule--that is, repeat the response if the stimulus or some aspect thereof is repeated from the preceding trial; otherwise, change the response. In addition, the experiment also revealed a second type of sequential effect, known as a task-switching effect Subjects were overall slower to respond when the task changed between adjacent trials than when there was no task change. A final result was that subjects were markedly impaired when the stimulus changed but the same response had to be repeated. This finding has been reported elsewhere when purely visual tasks have been used. Hence, it seems that particular difficulties arise, in such sequential testing situations, when type-distinct stimuli are grouped into the same response categories.

Grouping by proximity or similarity? Competition between the Gestalt principles in vision.

The nature of the psychological processes that underlie the Gestalt principles of grouping by proximity and grouping by similarity is examined. Similarity was defined relative to the principles of grouping by common colour and grouping by common shape. Subjects were presented with displays comprising a row of seven coloured shapes and were asked to rate the degree to which the central target shape grouped with either the right or the left flanking shapes. Across the displays the proximal and featural relationships between the target and flankers were varied. These ratings reflected persuasive effects of grouping by proximity and common colour; there was only weak evidence for grouping by common shape. Nevertheless, both common colour and common shape were shown to override grouping by proximity, under certain conditions. The data also show that to understand how the Gestalt principles operate it appears necessary to consider processes that operate within and between groups of elements that are initially identified on the basis of proximity. Whether such groups survive further analysis depends critically on the featural content of the constituent elements.

The effects of black tea and other beverages on aspects of cognition and psychomotor performance.

Nineteen healthy volunteers ingested 400 ml black tea, coffee, caffeinated water, decaffeinated tea or plain water on three occasions through the day (0900, 1400 and 1900 hours). A 2 x 2 factorial design with caffeine (0, 100 mg) and beverage type (water, tea) was employed, with coffee (100 mg caffeine) as a positive internal control, based on a five-way crossover. A psychometric test battery comprising critical flicker fusion (CFF), choice reaction time (CRT), short-term memory (STM) and subjective sedation (LARS) was performed at regular intervals throughout the day, and intensively so immediately following each beverage. Consumption of tea compared to water was associated with transient improvements in performance (CFF) within 10 min of ingestion and was not affected by the time of day. Caffeine ingestion was associated with a rapid (10 min) and persistent reduction in subjective sedation values (LARS), again independent of time of day, but did not acutely alter CFF threshold. Over the whole day, consumption of tea rather than water, and of caffeinated compared to decaffeinated beverages, largely prevented the steady decline in alertness (LARS) and cognitive capacity observed with water ingestion. The effects of tea and coffee were similar on all measures, except that tea consumption was associated with less variation in CFF over the whole day. No significant treatment effects were apparent in the data for the STM. Tea ingestion is associated with rapid increases in alertness and information processing capacity and tea drinking throughout the day largely prevents the diurnal pattern of performance decrements found with the placebo (no caffeine) condition. It appears that the effects of tea and coffee were not entirely due to caffeine per se; other factors either intrinsic to the beverage (e.g. sensory attributes or the presence of other biologically active substances) or of a psychological nature (e.g. expectancy) are likely to play a significant role in mediating the responses observed in this study.

Task constraints and visual feature binding.

Tel.: 00 44 1904 433135; fax: 00 44 1904 433181; e-mail: ptql@york.ac.uk. Experimental variations on the paradigm described by Kahneman, D., Treisman, A., Gibbs, B.J., 1992. Cognitive Psychology 24, 175-219 are reported. With these techniques two coloured letters are briefly presented, in a preview field. Following a short blank interval, a single coloured letter (the target) is presented. In the first experiment, reported here, subjects named the target letter, and in the second they named the target's colour. In neither of the experiments did the colour relationships between the target and preview items influence performance, but in both cases the shape relationships were important. Further experiments explored the notion that performance in the tasks was only an imperfect reflection of underlying perceptual processes because of the constraint of having to name the letters. When subjects were presented with unfamiliar characters and named the target's colour, then the colour relationships in the displays were important; residual effects of shape preview were also found. In final studies visually similar letters were used and different groups of subjects either named the target letter or the colour of the target. Of main interest was that the colour relations between the items exerted an effect when subjects named the target's colour. The theoretical and methodological implications of these results are discussed and the limitations of the original experiments are considered in the light of the reported findings.

The effect of triacylglycerol-fatty acid positional distribution on postprandial metabolism in subcutaneous adipose tissue.

We hypothesized that fatty acids at the sn-2 position of chylomicron triacylglycerol are preferentially released into the venous plasma (rather than being taken up and stored in the adipocytes) after hydrolysis by lipoprotein lipase (EC 3.1.1.34) in adipose tissue. Arteriovenous differences across adipose tissue were studied in eight healthy subjects on two occasions for 6 h after ingestion of different structured triacylglycerols rich in palmitic acid either at the sn-2 or the sn-1,3 positions. In particular the specific fatty acids making up lipoprotein fractions and plasma non-esterified fatty acids were analysed. After the different meals there were no differences between either postprandial arterialized or venous plasma metabolite concentrations. Chylomicron triacylglycerol extraction in adipose tissue was the same following the two types of fat. There was no difference between the specific fatty acid composition of the postprandial non-esterified fatty acid release from adipose tissue after ingestion of the two triacylglycerols, indicating that there was no preferential release of a saturated fatty acid at the sn-2 position.

The recovery of identity and relative position from visual input: further evidence for the independence of processing of what and where.

Four experiments examined the manner in which item identity and relative position are recovered from visual input. A successive same/different matching paradigm was designed in which each trial contained a prime and a target display. Each display contained a reference object (i.e., a "+") and a located object (i.e., a letter, which fell to either the right or the left of the "+"). In Experiment 1, subjects carried out identity judgments on the letters. Experiments 2 examined relative position judgments; in Experiment 3, subjects had to judge both item identity and relative position information. Overall, these initial data suggested that identity and positional information are recovered via independent mechanisms and that these operate concurrently. This suggestion was supported by the results of Experiment 4, which in turn disconfirmed an alternative response account of performance.

Dietary triacylglycerol structure and saturated fat alter plasma and tissue fatty acids in piglets.

Human and pig milk triacylglycerols contain a large proportion of palmitic acid (16:0) which is predominately esterified in the 2-position. Other dietary fats contain variable amounts of 16:0, with unsaturated fatty acids predominantly esterified in the 2-position. These studies determined if the amount or position of 16:0 in dietary fat influences the composition or distribution of liver, adipose tissue, lung, or plasma fatty acids in developing piglets. Piglets were fed to 18 d with sow milk or formula with saturated fat from medium-chain triglyceride (MCT), coconut or palm oil, or synthesized triacylglycerols (synthesized to specifically direct 16:0 to the 2-position) with, in total fatty acids, 30.7, 4.3, 6.5, 27.0, and 29.6% 16:0, and in 2-position fatty acids, 55.3, 0.4, 1.3, 4.4, and 69.9% 16:0, respectively. The percentage of 16:0 in the 2-position of adipose fat from piglets fed sow milk, palm oil, and synthesized triacylglycerols were similar and higher than in piglets fed MCT or coconut oil. Thus, the amount, not the position, of dietary 16:0 determines piglet adipose tissue 16:0 content. The effects of the diets on the plasma and liver triacylglycerols were similar, with significantly lower 16:0 in total and 2-position fatty acids of the MCT and coconut oil groups, and significantly higher 16:0 in the plasma and liver triacylglycerol 2-position of piglets fed the synthesized triacylglycerols rather than sow milk or palm oil. The lung phospholipid total and 2-position 16:0 was significantly lower in the MCT, coconut, and palm oil groups, but similar in the synthesized triacylglycerol group and sow milk group. The lung phospholipid total and 2-position percentage of arachidonic acid (20:4n-6) was significantly lower in all of the formula-fed piglets than in milk-fed piglets. The physiological significance of this is not known.

Effect of dietary triacylglycerol structure on lipoprotein metabolism: a comparison of the effects of dioleoylpalmitoylglycerol in which palmitate is esterified to the 2- or 1(3)-position of the glycerol.

The effect on lipoprotein metabolism of diets enriched in different isomers of dioleoylpalmitoylglycerol was studied. One diet contained fat in which palmitate was esterified to the two outer positions of the glycerol (OOP) and the other in which it was esterified to the middle carbon (OPO). The lipid composition of chylomicrons was similar in rats fed either fat blend. However, triacylglycerol (TAG) in chylomicrons from OPO fed animals was relatively enriched in palmitic acid, at the expense of stearic, oleic and linoleic acids. Silver phase HPLC and 2-positional analysis clearly demonstrated that the identity of the fatty acid in the 2-position was similar in both dietary and chylomicron TAG. No significant differences could be seen in the in vitro hydrolysis of chylomicron TAG from animals fed the two fats labelled with [14C]palmitate. As expected, following hydrolysis, palmitate was released as free fatty acid from chylomicrons isolated from OOP-fed animals but within 2-monoacylglycerol from those fed OPO. The enrichment of chylomicrons with palmitate in animals fed O[14C]PO resulted in increased delivery of [14C]palmitate to the liver. In a further series of experiments Golden Syrian hamsters were fed diets containing the fat blends and either 0.005% or 0.12% (w/w) cholesterol, for 28 days. No differences in fasting plasma lipoprotein concentrations were seen in response to the dietary fats. We conclude that, while these isometric triacylglycerols had transient effects on chylomicron metabolism, no significant longer term effect on plasma concentrations of endogenous lipoproteins could be found.

An examination of attentional control in the auditory modality: further evidence for auditory orienting.

Four experiments are reported that examine attentional control in the auditory modality. In Experiment 1, the subjects made detection responses to the onset of a monaurally presented pure tone that was preceded by a pure-tone cue. On a valid trial, the cue was presented in the same ear as the target; on an invalid trial, it was presented in the contralateral ear to the target; and on a neutral trial, it was presented in both ears. Overall performance was facilitated on valid trials in comparison with invalid trials. In later experiments, the subjects made choice decisions about the location of the target, and significant cuing effects were found relative to the neutral condition. Finally, performance was assessed in the presence of central (spoken) word cues. Here, the content of the cue specified the likely location of the target. Under these conditions, costs and benefits were found over a range of cue-target stimulus onset asynchronies. The results are discussed in terms of automatic and controlled attentional processes.

The relationship between stool hardness and stool composition in breast- and formula-fed infants.

"Constipation" and "hard stools" are associated with formula feeding of both term and preterm infants and, in the latter, can lead to life-threatening complications. This study tested the hypothesis that stool hardness is related to excretion of fatty acid (FA) soaps in term infants, and in the extreme to milk bolus obstruction in premature infants. Stools (n = 44) were collected from 20 formula-fed and 10 breast-fed infants aged 6 weeks and were classified using visual charts for stool hardness on a 5-point scale (1, watery; 5, hard). Stools were analysed for nitrogen, minerals, and lipid, the latter divided between the soap and nonsoap fractions. We explored the relationship between stool hardness or solids content and stool constituents, relative to both wet and dry weight. Calcium and FA soaps were the dominant factors significantly related to stool solids and hardness score across the breast- and formula-fed groups. An 8% increase in stool dry weight FA soap content corresponded to a 1-point change in stool hardness score. Stools from formula-fed infants had a higher solids content and were classified as significantly harder than those from breast-fed infants (hardness scores, 4.0 +/- 0.5 versus 2.6 +/- 0.7, mean +/- SD) and on both a wet- and dry-weight basis contained severalfold higher levels of minerals and lipid and considerably less carbohydrate. Differences in lipids between formula- and breast-fed infants' stools were due almost entirely to FAs (mainly C16:0 and C18:0) excreted as soaps (27.7 +/- 7.5% compared to 3.1 +/- 4.1% of dry weight), suggesting the groups differed markedly in their handling of saturated FAs. An inspissated stool sample from a premature infant requiring surgical disempaction of an obstructed small intestine was found to be enriched in FA and calcium relative to the preterm formula. FA soaps, predominantly saturated, accounted for one third of the stool dry weight. These data support the hypothesis that calcium FA soaps are positively related to stool hardness; we speculate that this may, at least in part, explain the greater stool hardness in formula- versus breast-fed infants and milk bolus obstruction in preterm infants. This conclusion is consistent with the physical properties of calcium FA soaps.

Evidence for the use of scene-based frames of reference in two-dimensional shape recognition.

A series of reaction time (RT) experiments are reported in which subjects had to match pairs of two-dimensional shapes. The shapes were either symmetrical or asymmetrical and were arranged into either symmetrical or asymmetrical displays. In the initial experiments the shapes straddled the vertical midline of the display. It was found that Same RTs to symmetrical displays were shorter than Same RTs to asymmetrical displays, and that Same RTs to symmetrical shapes were shorter than Same RTs to asymmetrical shapes. Moreover, display symmetry and shape symmetry produced an additive effect on responses. This pattern of results obtained when both shapes were presented simultaneously and when a delay was introduced between the presentation of one shape and the presentation of the other. However, display and shape symmetry interacted when the displays were rotated 90 deg within the plane so that the shapes straddled the horizontal meridian. The implications of these results are discussed in terms of both a transformational account of shape recognition and an account concerning the imposition and use of scene-based frames of reference.

Absorption of isomeric, palmitic acid-containing triacylglycerols resembling human milk fat in the adult rat.

The effect of the positional distribution of palmitic acid (16:0) in triacylglycerols (TAG) on 16:0 apparent absorption in adult rats was investigated. The rats were fed two diets which contained 30 energy % as fat with identical total fatty acid compositions, both containing 30% 16:0. The Betapol diet contained TAG with 73% of total 16:0 in the sn-2 position, the control diet contained TAG with 6% of total 16:0 in the sn-2 position. After six weeks on these diets, the rats were killed two or six hours after the last meal, and the small intestine was removed, cut into 10-cm segments, and the fatty acid composition of the segment's contents was determined. At both time points the amount of 16:0 in the intestinal segments starting at 40 cm from the stomach was much lower in the animals fed Betapol than in the animals fed the control diet. Overall absorption of 16:0 and stearic acid was significantly greater in the Betapol group. Absorption of oleic and linoleic acid from the small intestine was similar in both groups, although the overall absorption was significantly greater in the animals fed Betapol. Total fat absorption was significantly higher in the Betapol-fed rats than in the control-fed rats. No effect on calcium and nitrogen absorption, on plasma total cholesterol and TAG levels, and on bodyweights (growth) was seen. The data demonstrate that the positional distribution of the fatty acids in the TAG molecule affects the site of absorption in the small intestine and particularly the net absorption of saturated fatty acids.

The effect of triacylglycerol fatty acid positional distribution on postprandial plasma metabolite and hormone responses in normal adult men.

The present study has examined the possibility that the positional distribution of fatty acids on dietary triacyglycerol (TAG) influences the postprandial response to a liquid meal in adult subjects. Postprandial TAG, non-esterified fatty acids (NEFA), ketones, glucose, insulin and gastric inhibitory polypeptide (GIP) responses were monitored in sixteen normal adult male subjects over 6 h following consumption of test meals containing dietary TAG in which palmitic acid was predominantly on the sn-1 (Control) or sn-2 positions (Betapol). Plasma total TAG, chylomicron-rich TAG and chylomicron-poor TAG concentrations were identical in response to the two test meals. The peak increase (mean (SD)) in chylomicron TAG was 0.85 (0.46) mmol/l after the Control meal and 0.85 (0.42) mmol/l after the Betapol meal. Plasma glucose, insulin, GIP, NEFA and ketone concentrations were also very similar following the two meals. It is concluded that dietary TAG containing saturated fatty acids on the sn-2 position appear in plasma at a similar level and over a similar timescale to TAG in which saturated fatty acids are predominantly located on sn-1 or sn-3 positions. The results reported in the present study demonstrate that the positional distribution of fatty acids on dietary TAG is not an important determinant of postprandial lipaemia in adult male subjects, but do not exclude the possibility that different responses may occur when these dietary TAG are given long term.