The salutary characteristics of the tomato are normally related to its content of carotenoids, especially lycopene, and other antioxidants. Our purpose was to verify whether the daily intake of a beverage prototype called Lyc-o-Mato® containing a natural tomato extract (Lyc-o-Mato® oleoresin 6 %) was able to modify plasma and lymphocyte carotenoid concentrations, particularly those of lycopene, phytoene, phytofluene and β-carotene, and to evaluate whether this intake was sufficient to improve protection against DNA damage in lymphocytes. In a double-blind, cross-over study, twenty-six healthy subjects consumed 250 ml of the drink daily, providing about 6 mg lycopene, 4 mg phytoene, 3 mg phytofluene, 1 mg β-carotene and 1·8 mg α-tocopherol, or a placebo drink. Treatments were separated by a wash-out period. Plasma and lymphocyte carotenoid and α-tocopherol concentrations were determined by HPLC, and DNA damage by the comet assay. After 26 d of consumption of the drink, plasma carotenoid levels increased significantly: concentrations of lycopene were 1·7-fold higher (P<0·0001); of phytofluene were 1·6-fold higher (P<0·0001); of phytoene were doubled (P<0·0005); of β-carotene were 1·3-fold higher (P<0·05). Lymphocyte carotenoid concentrations also increased significantly: that of lycopene doubled (P<0·001); that of phytofluene was 1·8-fold higher (P<0·005); that of phytoene was 2·6-fold higher (P<0·005); that of β-carotene was 1·5-fold higher (P<0·01) In contrast, the α-tocopherol concentration remained nearly constant. The intake of the tomato drink significantly reduced (by about 42 %) DNA damage (P<0·0001) in lymphocytes subjected to oxidative stress. In conclusion, the present study supports the fact that a low intake of carotenoids from tomato products improves cell antioxidant protection.

To determine values for the digestible indispensable amino acid score (DIAAS), it is recommended that ileal amino acid (AA) digestibility values obtained in growing pigs are used to characterise protein quality in different foods. Therefore, an experiment was conducted to determine the standardised ileal digestibility (SID) of AA in eight cereal grains (yellow dent maize, Nutridense maize, dehulled barley, dehulled oats, polished white rice, rye, sorghum and wheat) fed to pigs, where SID values in pigs can be used to calculate approximate DIAAS values in humans. In the present experiment, twenty-four barrows with a T-cannula inserted in the distal ileum were allotted to eight diets and fed for three periods to give a total of nine replicate pigs per diet. Each period lasted 14 d, and ileal digesta samples were collected on days 13 and 14. Among the SID values obtained for all cereal grains, values for total indispensable AA were greatest (P< 0·05) in rice and lowest (P< 0·05) in rye and sorghum. The concentrations of SID indispensable AA in rice were less (P< 0·05) than in dehulled oats, but greater (P< 0·05) than in the other cereal grains, and the concentrations of SID indispensable AA in Nutridense maize were greater (P< 0·05) than in yellow dent maize and sorghum, but less (P< 0·05) than in the other cereal grains, except rye. In conclusion, results indicate that to meet dietary requirements for AA in humans, diets based on yellow dent maize or sorghum require more AA supplementation than diets based on other cereal grains.

Milk fat contains considerable amounts of saturated fatty acids, known to increase serum cholesterol. Little is known, however, about the relative effect of different milk products on risk factors for CHD. The aim of the present study was to compare the effects of Jarlsberg cheese (a Norwegian variety of Swiss cheese) with butter on serum lipoproteins, haemostatic variables and homocysteine. A controlled dietary study was performed with twenty-two test individuals (nine men and thirteen women) aged 23–54 years. The subjects consumed three isoenergetic test diets, with equal amounts of fat and protein, and containing either cheese (CH diet), butter+calcium caseinate (BC diet) or butter+egg-white protein (BE diet). The study was a randomised cross-over study and the subjects consumed each diet for 3 weeks, with 1 week when they consumed their habitual diet in between. Fasting blood samples were drawn at baseline and at the end of each period. Serum was analysed for lipids and plasma for haemostatic variables and homocysteine. Total cholesterol was significantly lower after the CH diet than after the BC diet (−0.27 mmol/l; P=0.03), while the difference in LDL-cholesterol was found to be below significance level (−0.22 mmol/l; P=0.06). There were no significant differences in HDL-cholesterol, triacylglycerols, apo A-I, apo B or lipoprotein (a), haemostatic variables and homocysteine between the diets. The results indicate that, at equal fat content, cheese may be less cholesterol increasing than butter.

1. The deposition of fat during pregnancy and its subsequent mobilization during lactation was studied in the rat. The utilization of protein during lactation was also investigated.

2. Fat accumulation was rapid and continuous from early pregnancy. Approximately one-third was deposited subcutaneously, the remainder being stored in central depots.

3. The volume of milk produced during lactation was varied by offering protein at two concentrations from day 2 post partum. Optimum lactation was achieved with a high-protein diet. The dams lost no body protein, but 60% of the total body fat was mobilized, despite a marked increase in food consumption. On a low-protein diet, food intake did not rise during lactation. Some body protein was catabolized and, again, 60% of the fat was mobilized although milk output, as judged by the gain in carcass energy of their pups, was reduced to approximately one-third of optimum.

4. Protein was used more efficiently by lactating rats, when compared with virgin controls.

5. We conclude that fat stored during pregnancy makes a major contribution to the energy costs of lactation, and that its mobilization is under hormonal rather than dietary control.

The effects of the anti-methanogenic compound, bromochloromethane (BCM), on rumen microbial fermentation and ecology were examined in vivo. Japanese goats were fed a diet of 50 % Timothy grass and 50 % concentrate and then sequentially adapted to low, mid and high doses of BCM. The goats were placed into the respiration chambers for analysis of rumen microbial function and methane and H2 production. The levels of methane production were reduced by 5, 71 and 91 %, and H2 production was estimated at 545, 2941 and 3496 mmol/head per d, in response to low, mid and high doses of BCM, respectively, with no effect on maintenance feed intake and digestibility. Real-time PCR quantification of microbial groups showed a significant decrease relative to controls in abundance of methanogens and rumen fungi, whereas there were increases in Prevotella spp. and Fibrobacter succinogenes, a decrease in Ruminococcus albus and R. flavefaciens was unchanged. The numbers of protozoa were also unaffected. Denaturing gradient gel electrophoresis and quantitative PCR analysis revealed that several Prevotella spp. were the bacteria that increased most in response to BCM treatment. It is concluded that the methane-inhibited rumen adapts to high hydrogen levels by shifting fermentation to propionate via Prevotella spp., but the majority of metabolic hydrogen is expelled as H2 gas.

Aside from existing drug therapies, certain lifestyle and nutritional factors are known to reduce the risk of osteoporosis. Among the nutritional factors, dried plum or prunes (Prunus domestica L.) is the most effective fruit in both preventing and reversing bone loss. The objective of the present study was to examine the extent to which dried plum reverses bone loss in osteopenic postmenopausal women. We recruited 236 women, 1–10 years postmenopausal, not on hormone replacement therapy or any other prescribed medication known to influence bone metabolism. Qualified participants (n 160) were randomly assigned to one of the two treatment groups: dried plum (100 g/d) or dried apple (comparative control). Participants received 500 mg Ca plus 400 IU (10 μg) vitamin D daily. Bone mineral density (BMD) of lumbar spine, forearm, hip and whole body was assessed at baseline and at the end of the study using dual-energy X-ray absorptiometry. Blood samples were collected at baseline, 3, 6 and 12 months to assess bone biomarkers. Physical activity recall and 1-week FFQ were obtained at baseline, 3, 6 and 12 months to examine physical activity and dietary confounders as potential covariates. Dried plum significantly increased BMD of ulna and spine in comparison with dried apple. In comparison with corresponding baseline values, only dried plum significantly decreased serum levels of bone turnover markers including bone-specific alkaline phosphatase and tartrate-resistant acid phosphatase-5b. The findings of the present study confirmed the ability of dried plum in improving BMD in postmenopausal women in part due to suppressing the rate of bone turnover.

1. Five rumen-fistulated cows were given freshly cut ryegrass (Lolium perenne L.) and lucerne (Medicago sativa L.), on separate occasions, to compare rates of particle breakdown and aspects of rumen fermentation.

2. Cattle were required to consume their daily allowance (offered ad lib.) in two 2 h feeding periods daily.

3. During the first 2 h feeding period, dry matter (DM) intakes of ryegrass (4.75 kg) and lucerne (4.85 kg) were similar. Eating reduced 46% of ryegrass and 61 % of lucerne to a size able to pass a 2 mm sieve (P < 0.001). Rumen DM particles retained on the 2 and 4 mm sieves had a low probability of passage out of the rumen, and accounted for only 6 % of faecal DM with both feeds.

4. Ryegrass was cleared from the rumen more slowly than lucerne. During eating, rumen DM particles which could not pass the 2 mm sieve increased from 323 to 511 g/kg for ryegrass and from 201 to 389 g/kg for lucerne. The rate of particle size reduction for lucerne stem was similar to that for ryegrass.

5. When lucerne was eaten the increases in rumen volatile fatty acid (VFA) and ammonia concentrations were much greater than for ryegrass (P < 0.001). The proportions of plant chlorophyll released during eating were similar for both feeds (0.570 and 0.607), but 2 h after eating 22.3 g had been released from lucerne (79.1 %) compared with 15.0 g from ryegrass (63.8%). The flux of water from the rumen to the omasum was similar for ryegrass (10.2 litres/h) and lucerne (12.7 litres/h) during eating, but declined to 6.0 litres/h after eating with the lucerne diet.

The present study provides the dietary intakes of macro elements (Ca, Mg, Na, K, P) and trace elements (Fe, Zn, Cu, Se) from the Italian total diet. The contribution of the most representative food groups of the total diet (cereals and cereal products, vegetables, fruit, milk and dairy products, meat and meat products, fish) to the daily intakes of these nutrients was also evaluated. The Italian total diet was formulated following the ‘market-basket’ approach. Cereals represented the primary sources of Cu (35 %), Fe (30 %) and Mg (27 %). About 89 % of the total daily intake of Fe was derived from plant foods. The vegetables food group was the main source of dietary K (27 %). Most of the Ca (59 %) and P (27 %) was derived from the milk-and-dairy food group. Of the dietary Zn, 41 % was provided by meat, which, together with the fish food group, was the primary source of Se (20 %). The adequacy of the Italian total diet with respect to nutritional elements was assessed by comparing the daily intakes with the average requirement values of the Italian recommended dietary allowances. The present findings indicated that the dietary patterns of the Italian total diet were generally consistent with current Italian dietary recommendations for both macro and trace elements. The major concern was for Ca, for which daily intake was 76 % of the average recommendation for the Italian population. It should not be ruled out that there could be a potential risk of inadequate Fe intake in some segments of the population.

In the present study the relationship between the consumption of different beverage groups and body-weight status in 5 years of study participation in German adolescents was investigated. We used anthropometric and dietary data from 3 d weighed records of 244 subjects between 9 and 18 years of age participating in the Dortmund Nutritional and Anthropometric Longitudinally Designed (DONALD) study. Only subjects with at least four out of six possible weighed dietary records were considered. A repeated-measures regression model (PROC MIXED) was used to analyse the effect of beverage consumption on body-weight status. BMI standard deviation scores (BMI-SDS) and body fat percentage (%BF) were chosen as the dependent variables. In boys, energetic beverage consumption was not associated with BMI-SDS or %BF, neither cross-sectionally nor prospectively. In girls, baseline consumption of energetic beverages did not predict baseline BMI-SDS, baseline %BF, or change in either variable over the study period. However, an increase in energetic beverage consumption over the study period was associated with an increase in BMI-SDS (+0.070 SDS/MJ increase in energetic beverage consumption; P = 0·01). Separate consideration of regular soft drinks and fruit juices revealed that, in girls, BMI-SDS increased with increased fruit juice consumption (+0·096 SDS/MJ increase in fruit juice consumption; P = 0·01), and to a lesser extent with regular soft drink consumption (+0·055 SDS/MJ increase in regular soft drink consumption; P = 0·08). In conclusion, these results suggest that an increase in energetic beverage consumption may result in weight gain, at least in adolescent girls.

Fish oils, rich in long-chain n-3 PUFA, are known to reduce various risk factors for CVD. However, conclusive evidence regarding the benefits of n-3 on arterial stiffness, a risk factor for CVD, has not yet been established. Consequently, we conducted the first study aimed to quantify the effects of n-3 supplementation on arterial stiffness through meta-analysis. Multiple databases and clinical trial registries were systematically searched up until September 2010 for randomised and controlled adult human clinical trials to investigate the effects of long-chain n-3 fatty acids on arterial stiffness. No limits were set on dosage sizes or sample characteristics. A total of ten n-3 trials met the final inclusion criteria; four using pulse wave velocity (PWV) and six using arterial compliance, measured as capacitive compliance or systemic arterial compliance, as respective outcome measures. Meta-analysis revealed that n-3 was statistically significant in effectively improving both PWV (g = 0·33; 95 % CI 0·12, 0·56; P < 0·01) and arterial compliance (g = 0·48; 95 % CI 0·24, 0·72; P < 0·001). There was no evidence of heterogeneity or publication bias. Results were not influenced by changes in blood pressure, heart rate or BMI. The findings of the present study reveal that supplementation with n-3 offers a scientifically supported means of reducing arterial stiffness. Reduction in arterial stiffness by n-3 may account for some of its purported cardioprotective effects.

A technique is described for feeding young sheep for long periods entirely by the infusion of volatile fatty acids into the rumen and protein and other essential nutrients into the abomasum. When the energy infused was twice the estimated requirement for maintenance, growth rate and nitrogen retention were essentially the same as in normally-fed sheep.

Previous studies have shown that various dietary components may be implicated in the aetiology of pancreatic cancer. However, the possible relationship between diet-related inflammation and the risk of pancreatic cancer has not yet been investigated. We examined the ability of a newly developed literature-derived dietary inflammatory index (DII) to predict the risk of pancreatic cancer in a case–control study conducted in Italy between 1991 and 2008. This included 326 incident cases and 652 controls admitted to the major teaching and general hospitals for non-neoplastic diseases, frequency-matched to cases by study centre, sex and age. The DII was computed based on dietary intake assessed using a validated and reproducible seventy-eight-item FFQ. Logistic regression models were used to estimate multivariable OR adjusted for age, sex, study centre, education, BMI, smoking status, alcohol drinking and history of diabetes. Energy adjustment was performed using the residual method. Subjects with higher DII scores (i.e. representing a more pro-inflammatory diet) had a higher risk of pancreatic cancer, with the DII being used as both a continuous variable (ORcontinuous 1·24, 95 % CI 1·11, 1·38) and a categorical variable (i.e. compared with the subjects in the lowest quintile of the DII, those in the second, third, fourth and fifth quintiles had, respectively, ORquintile2 v. 1 1·70, 95 % CI 1·02, 2·80; ORquintile3 v. 1 1·91, 95 % CI 1·16, 3·16; ORquintile4 v. 1 1·98, 95 % CI 1·20, 3·27; ORquintile5 v. 1 2·48, 95 % CI 1·50, 4·10; Ptrend= 0·0015). These data suggest that a pro-inflammatory diet increases the risk of pancreatic cancer.

Studies in animals and human subjects indicate that gut-derived bacterial endotoxins may play a critical role in the development of non-alcoholic fatty liver disease (NAFLD). In the present study, we investigated if the liver is also sensitised by other microbial components during the onset of fructose-induced steatosis in a mouse model. C57BL/6 mice were either fed with 30 % fructose solution or tap water (control) with or without antibiotics for 8 weeks. Expression of toll-like receptors (TLR)1–9, TNF-α, inducible NO synthase (iNOS), myeloid differentiation factor 88 (MyD88) and number of F4/80 positive cells in the liver were assessed. Occludin protein, DNA of microbiota in the small and large intestine and retinol binding protein 4 (RBP4) in plasma were analysed using Western blot, DNA fingerprinting and ELISA, respectively. F4/80 positive cells were determined by immunohistochemistry. The accumulation of TAG found in the livers of fructose-fed mice was associated with a significant induction of TLR 1–4 and 6–8. Plasma RBP4 concentration and hepatic mRNA expression levels of TNF-α, iNOS, MyD88 and number of F4/80 positive cells of fructose-fed animals were significantly higher than those of controls; however, these effects of fructose were attenuated in antibiotic-treated mice. Whereas protein concentration of occludin was lower in the duodenum of fructose-treated mice, no systematic alterations of microbiota were found in this part of the intestine. Taken together, these data support the hypothesis that (1) an increased intestinal translocation of microbial components and (2) an increased number of F4/80 positive cells and induction of several TLR and dependent pathways (e.g. MyD88 and iNOS) may be involved in the onset of fructose-induced NAFLD.

The Maillard reaction produces coloured, macromolecular materials (melanoidins) in a variety of foods, on heating. Significant quantities may enter the human gut on a daily basis, but there is little information on their metabolism in the human colon. As the large bowel contains a diverse population of bacteria involved in normal bowel function, it is possible that melanoidins are metabolized therein. Depending on the bacteria involved, there may be disease or health implications. The aim of the present study was to use in vitro models to determine the digestibility of melanoidins and the effect of melanoidins on colonic bacteria in the gastrointestinal tract. Melanoidins were prepared and the effects of simulated upper-gut secretions on their stability determined in a model system. The effects of faecal bacteria were also determined, in batch culture, with a combination of phenotypic and genotypic (probes) criteria being used to identify the microbial diversity involved. Simulation of peptic and pancreatic digestion showed that the melanoidins did not produce detectable amounts of low-molecular-mass degradation products. However, melanoidins affected the growth of gut bacteria during mixed culture growth. The effect was to cause a non-specific increase in the anaerobic bacteria enumerated. This in vitro study indicates that melanoidins can affect the growth of human large-bowel bacteria and serves to demonstrate possible effects that may occur in vivo. Given the large and varied number of food items that contain Maillard reaction products, this may have relevance for lower-gut health.

1. The metabolic effects of increasing or decreasing the usual energy intake for only 1 d were assessed in eight adult volunteers. Each subject lived for 28 h in a whole-body calorimeter at 26° on three separate occasions of high, medium or low energy intake. Intakes (mean±SEM) of 13830 ± 475 (high), 8400 ± 510 (medium) and 3700 ± 359 (low) kJ/24 h were eaten in three meals of identical nutrient composition.

2. Energy expenditure was measured continuously by two methods: direct calorimetry, as total heat loss partitioned into its evaporative and sensible components; and indirect calorimetry, as heat production calculated from oxygen consumption and carbon dioxide production. For the twenty-four sessions there was a mean difference of only 1.2 ± 0.14 (SEM)% between the two estimates of 24 h energy expenditure, with heat loss being less than heat production. Since experimental error was involved in both estimates it would be wrong to ascribe greater accuracy to either one of the measures of energy expenditure.

3. Despite the wide variation in the metabolic responses of the subjects to over-eating and under-eating, in comparison with the medium intake the 24 h heat production increased significantly by 10% on the high intake and decreased by 6% on the low intake. Mean (± SEM) values for 24 h heat production were 8770 ± 288, 7896 ± 297 and 7495 ± 253 kJ on the high, medium and low intakes respectively. The effects of over-eating were greatest at night and the resting metabolic rate remained elevated by 12% 14 h after the last meal. By contrast, during under-eating the metabolic rate at night decreased by only 1%.

4. Evaporative heat loss accounted for an average of 25% of the total heat loss at each level of intake. Changes in evaporative heat loss were +14% on the high intake and −10% on the low intake. Sensible heat loss altered by +9% and −5% on the high and low intakes respectively.

5. It is concluded that (a) the effects on 24 h energy expenditure of over-feeding for only 1 d do not differ markedly from those estimated by some other workers after several weeks of increasing the energy intake; (b) the resting metabolic rate, measured at least 14 h after the last meal, can be affected by the previous day's energy intake; (c) the zone of ambient temperature within which metabolism is minimal is probably altered by the level of energy intake.

Despite the potential link between snack food intake and obesity and the reportedly high prevalence of snacking among adolescents, adolescent snack food patterns (types of foods consumed, frequency and portion size) have not been extensively examined. This study examines these issues using data on the snacking patterns of adolescents aged 13–16 years who took part in the 1997 National Diet and Nutrition Survey (NDNS) and that from a Northern Irish (NI) cohort of adolescents collected 8 years later, in 2005. Overall energy intake was significantly higher in the NI adolescents in 2005 compared with the NDNS adolescents in 1997 (P < 0·01). Consequently, energy intake from snacks was significantly higher in the NI cohort (P < 0·01) and a trend for a higher % energy intake from snacks compared with the NDNS group was observed (median 32·5 % v. 29·8 %, respectively). Sugar-sweetened carbonated and soft drinks remained the most popular choice of snack over this 8-year period; however, both the portion size consumed and frequency of consumption were significantly higher among the adolescents in 2005 compared with those in 1997 (P = 0·022 and P = 0·014, respectively). Despite the lower popularity, and correspondingly lower frequency of milks and beverages, the portion size of both food groups was significantly higher among the adolescents in 2005 compared with those in 1997 (P < 0·001 and P = 0·007, respectively). These findings may provide scope for policy interventions to place particular emphasis on reducing typical portion sizes consumed of popular snack choices, in particular high-energy carbonated and soft drinks, among UK adolescents.

Increasing evidence suggests that the Mediterranean diet can reduce the risk of CVD. Olive oil is the hallmark of this dietary pattern. We conducted a meta-analysis of case–control, prospective cohort studies and a randomised controlled trial investigating the specific association between olive oil consumption and the risk of CHD (101 460 participants) or stroke (38 673 participants). The results of all observational studies were adjusted for total energy intake. The random-effects model assessing CHD as an outcome showed a relative risk (RR) of 0·73 (95 % CI 0·44, 1·21) in case–control studies and 0·96 (95 % CI 0·78, 1·18) in cohort studies for a 25 g increase in olive oil consumption. In cohort studies, the random-effects model assessing stroke showed a RR of 0·74 (95 % CI 0·60, 0·92). The random-effects model combining all cardiovascular events (CHD and stroke) showed a RR of 0·82 (95 % CI 0·70, 0·96). Evidence of heterogeneity was apparent for CHD, but not for stroke. Both the Egger test (P= 0·06) and the funnel plot suggested small-study effects. Available studies support an inverse association of olive oil consumption with stroke (and with stroke and CHD combined), but no significant association with CHD. This finding is in agreement with the recent successful results of the PREDIMED randomised controlled trial.

We assessed the effect of ingestion of green tea (GT) extract along with a low-energy diet (LED) on resting energy expenditure (REE), substrate oxidation and body weight as GT has been shown to increase energy expenditure and fat oxidation in the short term in both animals and people. Forty-six overweight women (BMI 27·6 (sd 1·8) kg/m2) were fed in energy balance from day 1 to day 3, followed by a LED with GT (1125 mg tea catechins +225 mg caffeine/d) or placebo (PLAC) from day 4 to day 87. Caffeine intake was standardised to 300 mg/d. Energy expenditure was measured on days 4 and 32. Reductions in weight (4·19 (sd 2·0) kg PLAC, 4·21 (sd 2·7) kg GT), BMI, waist:hip ratio, fat mass and fat-free mass were not statistically different between treatments. REE as a function of fat-free mass and fat mass was significantly reduced over 32 d in the PLAC group (P<0·05) but not in the GT group. Dietary restraint increased over time (P<0·001) in both groups, whereas disinhibition and general hunger decreased (P<0·05). The GT group became more hungry over time and less thirsty, and showed increased prospective food consumption compared with PLAC (P<0·05). Taken together, the ingestion of GT along with a LED had no additional benefit for any measures of body weight or body composition. Although the decrease in REE as a function of fat-free mass and fat mass was not significant with GT treatment, whereas it was with PLAC treatment, no significant effect of treatment over time was seen, suggesting that a robust limitation of REE reduction during a LED was not achieved by GT.

Total energy intake and the frequency and size of meals are profoundly influenced by the socio-cultural context in which it occurs. Simply eating with one other person increases the average amount ingested in meals by 44% and with more people present the average meal size grows even larger. The impact of social facilitation of energy intake on the individual appears to result from genetic effects both on the individuals' sensitivity to the presence of other people and also on the number of other people an individual tends to eat with. Culture markedly affects the choice of foods in the diet and the pattern of meals over the day. However, many of the social, psychological and physical variables that influence intake are similar across cultures.

Dietary Si, as soluble orthosilicic acid (OSA), may be important for the growth and development of bone and connective tissue. Beer appears to be a major contributor to Si intake, although the Si content of beer and its bioavailability in human subjects have not been well established. Here we investigated the Si content of different beers and then estimated Si absorption from beer in healthy volunteers. The Si content of seventy-six different beers was estimated using inductively coupled plasma optical emission spectrometry and one of the beers, used in the ingestion study, was ultrafiltered to determine OSA content. Next, following the ingestion of 0·6 litres beer (22·5mg Si; 4·6% (v/v) ethanol), serum and urinary Si levels were measured in nine healthy volunteers over a 6h period. A solution of OSA was similarly investigated as a positive control and water and 4·6% ethanol as negative controls. The mean Si level of beer was 19·2 (SD 6·6) mg/l; the median Si level was 18·0mg/l. There was no significant difference in the Si levels of the different beers by geographical origin or type of beer. Serum and urinary Si levels increased considerably following the ingestion of beer or a solution of OSA but not with the ingestion of either 4·6% ethanol or water. The ultrafilterability of Si from beer (about 80%) and its absorption in volunteers (about 55%) was comparable with that of a solution of OSA suggesting that Si in beer is present chiefly in a monomeric form and is readily bioavailable.