Nuts contain significant amounts of essential micronutrients that are associated with an improved health status when consumed at doses beyond those necessary to prevent deficiency states. Nuts do not contain cholesterol, but they are rich in chemically related phytosterols, a class of compounds that interfere with intestinal cholesterol absorption and thus help lower blood cholesterol. Nuts also contain folate, a B-vitamin necessary for normal cellular function that plays an important role in detoxifying homocysteine, a sulphur-containing amino acid with atherothrombotic properties that accumulates in plasma when folate status is subnormal. Compared to other common foodstuffs, nuts have an optimal nutritional density with respect to healthy minerals, such as calcium, magnesium and potassium. Like that of most vegetables, the sodium content of nuts is very low. A high intake of calcium, magnesium and potassium, together with a low sodium intake, is associated with protection against bone demineralisation, arterial hypertension, insulin resistance, and overall cardiovascular risk. Phytosterols might justify part of the cholesterol-lowering effect of nut intake beyond that attributable to fatty acid exchange, while the mineral richness of nuts probably contributes to the prevention of diabetes and coronary heart disease observed in epidemiological studies in association with frequent nut consumption.

Globally, colorectal cancer (CRC) is a leading cause of mortality from malignant disease. Case–control and cohort studies provide strong support for a role of diet in the aetiology of CRC. However to establish causal relationships and to identify more precisely the dietary components involved, intervention studies in human subjects are required. Cancer is an impractical endpoint in terms of numbers, cost, study duration and ethical considerations. Consequently, intermediate biomarkers of the disease are required. This review aims to provide an overview of the intermediate endpoints available for the study of CRC, particularly non-invasive faecal biomarkers. Examples of their use in dietary intervention studies are given.

Opioid agonistic and antagonistic peptides which are inactive within the sequence of the precursor milk proteins can be released and thus activated by enzymatic proteolysis, for example during gastrointestinal digestion or during food processing. Activated opioid peptides are potential modulators of various regulatory processes in the body. Opioid peptides can interact with subepithelial opioid receptors or specific luminal binding sites in the intestinal tract. Furthermore, they may be absorbed and then reach endogenous opioid receptors.

We aimed to determine the effects of variations in dietary composition on equine gut microbiota and their fermentation products, and proposed that dietary modifications profoundly affect microbial ecosystems and their metabolites. Bacterial communities within the large intestine of three groups of horses were compared using oligonucleotide-RNA hybridisation methodology. Each group consisting of six horses was maintained on (1) a grass-only diet, (2) a concentrate diet (i.e. supplemented with hydrolysable carbohydrates) and (3) a concentrate diet but horses were affected by simple colonic obstruction and distension (SCOD), a prevalent form of dietary-induced intestinal disease. We show that in response to dietary change and intestinal disease, there is a progressive and significant increase in Lachnospiraceae, the Bacteroidetes assemblage and the lactic acid-producing, Bacillus–Lactobacillus–Streptococcus (BLS) group. In contrast, there is a corresponding decrease in the proportion of obligate fibrolytic, acid-intolerant bacteria, Fibrobacter and Ruminococcaceae. Assessment of monocarboxylic acids indicated that there are significantly higher concentrations of lactic acid in the colonic contents of horses maintained on a concentrate diet and those suffering from SCOD, correlating with the observed increase in the population abundance of the BLS group. However, the population size of the Veillonellaceae (lactate utilisers) remained constant in each study group. The inability of this group to respond to increased lactic acid may be a contributory factor to the build-up of lactic acid observed in horses fed a concentrate diet and those suffering from SCOD.

The clustering of cardiovascular risk factors such as abdominal obesity, hypertension, dyslipidaemia and glucose intolerance in the same persons has been called the metabolic or insulin-resistance syndrome. In 1998 WHO proposed a unifying definition for the syndrome and chose to call it the metabolic syndrome rather than the insulin-resistance syndrome. Although insulin resistance has been considered as a common denominator for the different components of the syndrome, there is still debate as to whether it is pathogenically involved in all of the different components of the syndrome. Clustering of the syndrome in families suggests a genetic component. It is plausible that so-called thrifty genes, which have ensured optimal storage of energy during periods of fasting, could contribute to the phenotype of the metabolic syndrome. Common variants in a number of candidate genes influencing fat and glucose metabolism can probably, together with environmental triggers, increase susceptibility to the syndrome. Among these, the genes for β3-adrenergic receptor, hormone-sensitive lipase, lipoprotein lipase, IRS-1, PC-1, skeletal muscle glycogen synthase, etc. appear to increase the risk of the metabolic syndrome. In addition, novel genes may be identified by genome-wide searches.

It is unclear whether postprandial blood glucose or insulin exerts a regulatory function in short-term appetite regulation in humans. The aim of this study was to investigate, by use of meta-analysis, the role of blood glucose and insulin in short-term appetite sensation and energy intake (EI) in normal weight and overweight participants. Data from seven test meal studies were used, including 136 healthy participants (ALL) (92 normal weight (NW) and 44 overweight or obese (OW)). All meals were served as breakfasts after an overnight fast, and appetite sensations and blood samples were obtained frequently in the postprandial period. Finally, an ad libitum lunch was served. Data were analysed by fixed effects study level (SL) meta-regression analysis and individual participant data (IPD) regression analysis, using STATA software. In SL analysis, postprandial insulin response was associated with decreased hunger in ALL, NW and OW (P < 0·019), and with increased satiety in NW (P = 0·004) and lower subsequent EI in OW (P = 0·022). Multivariate IPD analysis showed similar associations, but only in NW for hunger, satiety and EI (P < 0·028), and in ALL for EI (P = 0·016). The only association involving blood glucose was the multivariate IPD analysis showing an inverse association between blood glucose and EI in ALL (P = 0·032). Our results suggest that insulin, but not glucose, is associated with short-term appetite regulation in healthy participants, but the relationship is disrupted in the overweight and obese. We conclude that the postprandial insulin response may be an important satiety signal, and that central nervous system insulin resistance in overweight might explain the blunted effect on appetite.

A human study was carried out to investigate whether tomato juice, rich in natural lycopene and fortified with vitamin C, is able to reduce several biomarkers of oxidative stress and inflammation and whether the effect can be attributed to lycopene, vitamin C or any other micronutrient. Following a 2-week depletion phase, volunteers were assigned randomly to ingest either tomato juice with (LC) or without (L) vitamin C fortification for 2 weeks (daily dose 20·6 mg lycopene and 45·5/435 mg vitamin C). Plasma and urine were analysed for carotenoids and vitamin C, lipid status, antioxidant capacity, thiobarbituric acid reactive substances (TBARS) and 8-epi-PGF2α, protein carbonyls, cytokines IL-1β and TNFα and C-reactive protein (CRP). The consumption of tomato juice led to a reduction in total cholesterol levels (L: 157·6 v. 153·2 mg/dl, P = 0·008; LC: 153·4 v. 147·4 mg/dl, P = 0·002) and that of CRP (L: 315·6 v. 262·3 μg/l, P = 0·017; LC: 319·2 v. 247·1 μg/l, P = 0·001) in both groups. The vitamin C-fortified juice slightly raised the antioxidant capacity in urine and decreased TBARS in plasma and urine. All other markers were affected to a lesser extent or remained unchanged. Cholesterol reduction was correlated with lycopene uptake (P = 0·003), whereas the other effects could not be related with particular micronutrients. Any beneficial effects of tomato consumption for human health cannot be attributed only to lycopene and, as the additional supplementation with ascorbic acid indicates, a variety of antioxidants might be needed to optimize protection against chronic diseases.

On the basis of the high fat content of nuts, they are traditionally considered as foods that provide a high amount of energy. However, epidemiologic and clinical observations do not indicate an association between nut intake and increased BMI. There is a notorious variability in macronutrient composition among nuts, although they have some consistent patterns. Nuts contain all major macronutrients: protein, carbohydrate, and fat. The total protein content is relatively high, which makes them a good source of plant protein (especially for vegetarians). Although nuts contain low amounts of some essential amino acids, this is not a nutritional concern due to the complement of protein. In addition, nuts have a low lysine:arginine ratio, which is inversely associated with the risk of developing hypercholesterolemia and atherosclerosis. Carbohydrates are the second highest macronutrient in nuts in terms of total calories provided. The fat fraction is characterized by a high amount of unsaturated fatty acids and a low content of saturated fatty acids. In conclusion, the high content in unsaturated fatty acids, the low lysine:arginine ratio, and the presence of other bioactive molecules (such as fibre, phytosterols, vitamin and other antioxidants, and minerals) make the addition of nuts to healthy diets a useful tool for the prevention of cardiovascular heart diseases.

1. Of the nineteen plants screened, six were found to contain large quantities of condensed tannins. Black locust (Robinia pseudo-Acacia), bush clover (Lespedeza bicolor), wistaria (Wistaria floribunda) and Japanese knotgrass (Reynoutria japonica) were used for the present experiment. Tannins of the investigated plants were fractionated into three or four molecular forms, according to the degree of polymerization, by chromatography on a column of Sephadex LH-20.

2. The protein-precipitating capacity of the fractionated tannins increased with the increase in degree of polymerization. The inhibitory effect of tannins on trypsin (EC 3.4.21.4), a-amylase (EC 3.2.1.1) and lipase (EC 3.1.1.3) activities in vitro also increased with the increase in degree of polymerization. The digestion of tannin-bovine serum albumin complex by trypsin was related to the degree of polymerization of tannins complexed.

3. Inclusion of black locust tannins in the diet (10 g/kg) depressed the activities of trypsin and α-amylase in the upper, middle and lower parts of the intestine of the rats, but the lipase activity was increased in the middle part and remained unaffected in the upper and lower parts. It is presumed that the tannins have little affinity for lipase.

4. Digestion trials, when the microflora level of the alimentary canal of rats was reduced by dietary antibiotic treatment, revealed that the inclusion of tannins in the diet (20 g/kg) depressed the digestibilities of proximate constituents, except crude fat, and increased faecal bile acid excretion.

1. A method is described whereby a large quantity of rumen microbial dry matter of high purity was isolated from whole rumen contents obtained from abattoirs, by means of a continuous process of one filtration through four sieves followed by three differential centrifugations.

2. The contents of ash, carbohydrate, lipid, nitrogen, RNA, DNA and individual amino acids of the three centrifugal fractions are given and compared with values summarized from more than sixty published reports on the chemical composition of rumen micro-organisms isolated from both whole rumen contents and pure cultures.

3. The amino acid composition of isolated rumen micro-organisms, in particular that of the bacteria, was found to be remarkably constant.

1. The effects of dietary supplements of ω 3 polyunsaturated fatty acids on the fatty acid composition of platelets and plasma choline phosphoglycerides were studied in vegans and in omnivores.

2. A supplement of 18:3ω3 led to an increase in 20:5 ω3 but was less effective than one of 20:5ω3+22:6ω3.

Nucleotides, nucleosides and nucleobases belong to the non-protein-nitrogen (NPN) fraction of milk. The largest amounts of ribonucleosides and ribonucleotides – ribose forms only were considered in this review – were measured directly after parturition in bovine milk and other ruminants as well as in the milk of humans. Generally, concentrations of most of the nucleos(t)ides tend to decrease gradually with advancing lactation period or nursing time. The species-specific pattern of these minor constituents in milk from different mammals is a remarkable property and confirms, at least, the specific physiological impact of these minor compounds in early life. The physiological capacity of these compounds in milk is given by the total potentially available nucleosides. The main dietary sources of nucleos(t)ides are nucleoproteins and nucleic acids which are converted in the course of intestinal digestion into nucleosides and nucleobases the preferred forms for absorption in the intestine. Thus, nucleosides and nucleobases are suggested to be the acting components of dietary and/or supplemented nucleic acid-related compounds in the gut. They are used by the body as exogenous trophochemical sources and can be important for optimal metabolic functions. Up to 15 % of the total daily need for a breast-fed infant was calculated to come from this dietary source. Concerning their biological role they not only act as metabolites but are also involved as bioactive substances in the regulation of body functions. Dietary nucleotides affect immune modulation, e.g. they enhance antibody responses of infants as shown by a study with more than 300 full-term healthy infants. Dietary nucleos(t)ides are found to contribute to iron absorption in the gut and to influence desaturation and elongation rates in fatty acid synthesis, in particular long-chain polyunsaturated fatty acids in early stages of life. The in vitro modulation of cell proliferation and apoptosis has been described by ribonucleosides, in particular by modified components using human cell culture models. Due to the bio- and trophochemical properties of dietary nucleos(t)ides, the European Commission has allowed the use of supplementation with specific ribonucleotides in the manufacture of infant and follow-on formula. From the technochemical point of view, the ribonucleoside pattern is influenced by thermal treatment of milk. In addition ribonucleosides are useful indicators for quantifying adulterations of milk and milk products.

The impact of ingesting various foods on psychological and behavioural functions is a topic of both interest and concern to the general public. In this article, the scientific literature concerning demonstrated cause-and-effect relationships is reviewed, beginning with methodological considerations specific to the quantification of particular behaviours and psychological events. The essential function of food is to satisfy hunger and the need for essential nutrients. The contributions of macronutrients to appetite and satiety are described, as well as their impact on metabolism and energy balance. Functional properties of macronutrient substitutes (high intensity sweeteners, fat replacers) and flavour enhancers are examined in relation to their contribution to hunger, satiety, and energy balance. The effects of foods and individual nutrients on the performance of diverse psychomotor tasks are studied with consideration given to the various validated quantitative tools used to assess behaviour. The effects of food components on activation, sedation, and affective states such as dysphoria are also reviewed, with special attention given to brain function and neuroactive substances such as serotonin and the endorphins. The case of hyperactivity in children is given special emphasis with reference to the potential influence of sugar and food additives. Safety issues related to food constituents and additives are discussed. Finally, a set of criteria is proposed for the evaluation and elaboration of studies in the behavioural and psychological fields, along with suggestions for future research.

Critical insights into the etiology of insulin resistance have been gained by the use of animal models where insulin action has been modulated by strictly controlled dietary interventions not possible in human studies. Overall, the literature has moved from a focus on macronutrient proportions to understanding the unique effects of individual subtypes of fats, carbohydrates and proteins. Substantial evidence has now accumulated for a major role of dietary fat subtypes in insulin action. Intake of saturated fats is strongly linked to development of obesity and insulin resistance, while that of polyunsaturated fats (PUFAs) is not. This is consistent with observations that saturated fats are poorly oxidized for energy and thus readily stored, are poorly mobilized by lipolytic stimuli, impair membrane function, and increase the expression of genes associated with adipocyte profileration (making their own home). PUFAs have contrasting effects in each instance. It is therefore not surprising that increased PUFA intake in animal models is associated with improved insulin action and reduced adiposity. Less information is available for carbohydrate subtypes. Early work clearly demonstrated that diets high in simple sugars (in particular fructose) led to insulin resistance. However, again attention has rightly shifted to the very interesting issue of subtypes of complex carbohydrates. While no differences in insulin action have yet been shown, differences in substrate flux suggest there could be long-term beneficial effects on the fat balance of diets enhanced in slowly digested/resistant starches. A new area of major interest is in protein subtypes. Recent results have shown that rats fed high-fat diets where the protein component was from casein or soy were insulin-resistant, but when the protein source was from cod they were not. These are exciting times in our growing understanding of dietary factors and insulin action. While it has been clear for some time that ‘oils ain't oils’, the same is now proving true for carbohydrates and proteins.

Regulation of energy homeostasis requires precise coordination between peripheral nutrient-sensing molecules and central regulatory networks. Ghrelin is a twenty-eight-amino acid orexigenic peptide acylated at the serine 3 position mainly with an n-octanoic acid, which is produced mainly in the stomach. It is the endogenous ligand of the growth hormone secretagogue (GHS) receptors. Since plasma ghrelin levels are strictly dependent on recent food intake, this hormone plays an essential role in appetite and meal initiation. In addition, ghrelin is involved in the regulation of energy homeostasis. The ghrelin gene is composed of four exons and three introns and renders a diversity of orexigenic peptides as well as des-acyl ghrelin and obestatin, which exhibit anorexigenic properties. Ghrelin stimulates the synthesis of neuropeptide Y (NPY) and agouti-related protein (AgRP) in the arcuate nucleus neurons of the hypothalamus and hindbrain, which in turn enhance food intake. Ghrelin-expressing neurons modulate the action of both orexigenic NPY/AgRP and anorexigenic pro-opiomelanocortin neurons. AMP-activated protein kinase is activated by ghrelin in the hypothalamus, which contributes to lower intracellular long-chain fatty acids, and this appears to be the molecular signal for the expression of NPY and AgRP. Recent data suggest that ghrelin has an important role in the regulation of leptin and insulin secretion and vice versa. The present paper updates the effects of ghrelin on the control of energy homeostasis and reviews the molecular mechanisms of ghrelin synthesis, as well as interaction with GHS receptors and signalling. Relationships with leptin and insulin in the regulation of energy homeostasis are addressed.

Epidemiological studies show that diet is linked to the risk of developing CVD. The objective of this meta-analysis was to estimate the association between empirically derived dietary patterns and CVD. PubMed was searched for observational studies of data-driven dietary patterns that reported outcomes of cardiovascular events. The association between dietary patterns and CVD was estimated using a random-effects meta-analysis with 95 % CI. Totally, twenty-two observational studies met the inclusion criteria. The pooled relative risk (RR) for CVD, CHD and stroke in a comparison of the highest to the lowest category of prudent/healthy dietary patterns in cohort studies was 0·69 (95 % CI 0·60, 0·78; I2=0 %), 0·83 (95 % CI 0·75, 0·92; I2=44·6 %) and 0·86 (95 % CI 0·74, 1·01; I2=59·5 %), respectively. The pooled RR of CHD in a case–control comparison of the highest to the lowest category of prudent/healthy dietary patterns was 0·71 (95 % CI 0·63, 0·80; I2=0 %). The pooled RR for CVD, CHD and stroke in a comparison of the highest to the lowest category of western dietary patterns in cohort studies was 1·14 (95 % CI 0·92, 1·42; I2=56·9 %), 1·03 (95 % CI 0·90, 1·17; I2=59·4 %) and 1·05 (95 % CI 0·91, 1·22; I2=27·6 %), respectively; in case–control studies, there was evidence of increased CHD risk. Our results support the evidence of the prudent/healthy pattern as a protective factor for CVD.

Different dietary proteins vary in their ability to influence satiety and reduce food intake. The present study compared the effects of four protein meals, whey, tuna, turkey and egg albumin, on postprandial glucose and insulin concentrations as well as on appetite measures and energy intake in twenty-two lean, healthy men. This was a randomised, cross-over design study where participants consumed four liquid test meals on separate occasions followed by the collection of regular blood samples (fasting, +30, 60, 90, 120, 180 and 240 min). They were then offered a buffet meal 4 h later. The blood glucose response after the consumption of the test meal, as an incremental area under the curve (AUC), was significantly lower with the whey meal than with the turkey (P < 0·023) and egg (P < 0·001) meals, but it was not lower than with the tuna meal (P < 0·34). The AUC blood insulin after the consumption of the test meal was significantly higher with the whey meal than with the tuna, turkey and egg meals (all P < 0·001). The AUC rating of hunger was significantly lower with the whey meal than with the tuna (P < 0·033), turkey (P < 0·001) and egg (P < 0·001) meals. Mean energy intake at the ad libitum meal was significantly lower (P < 0·001) with the whey meal than with the tuna, egg and turkey meals. There was a strong relationship between self-rated appetite, postprandial insulin response and energy intake at lunch. Whey protein meal produced a greater insulin response, reduced appetite and decreased ad libitum energy intake at a subsequent meal compared with the other protein meals, indicating a potential for appetite suppression and weight loss in overweight or obese individuals.

Dietary polyphenols are suggested to participate in the prevention of CVD and cancer. It is essential for epidemiological studies to be able to compare intake of the main dietary polyphenols in populations. The present paper describes a fast method suitable for the analysis of polyphenols in urine, selected as potential biomarkers of intake. This method is applied to the estimation of polyphenol recovery after ingestion of six different polyphenol-rich beverages. Fifteen polyphenols including mammalian lignans (enterodiol and enterolactone), several phenolic acids (chlorogenic, caffeic, m-coumaric, gallic, and 4-O-methylgallic acids), phloretin and various flavonoids (catechin, epicatechin, quercetin, isorhamnetin, kaempferol, hesperetin, and naringenin) were simultaneously quantified in human urine by HPLC coupled with electrospray ionisation mass-MS (HPLC-electrospray-tandem mass spectrometry) with a run time of 6 min per sample. The method has been validated with regard to linearity, precision, and accuracy in intra- and inter-day assays. It was applied to urine samples collected from nine volunteers in the 24 h following consumption of either green tea, a grape-skin extract, cocoa beverage, coffee, grapefruit juice or orange juice. Levels of urinary excretion suggest that chlorogenic acid, gallic acid, epicatechin, naringenin or hesperetin could be used as specific biomarkers to evaluate the consumption of coffee, wine, tea or cocoa, and citrus juices respectively.

The water-soluble, mixed-linkage β-glucan, a form of soluble dietary fibre, is considered the main biologically active component responsible for the capacity of many oat products to lower postprandial glycaemia and fasting plasma cholesterol in human subjects. The present review discusses the physical and chemical properties of oat β-glucan that are considered important predictors of these beneficial metabolic effects. In vitro modelling and animal and human studies have provided compelling evidence showing that the ability of oat β-glucan to increase the viscosity of digesta in the gastrointestinal tract (GIT) is a primary determinant of its blood-glucose and cholesterol-lowering properties. Therefore, the chemical structure, molecular weight (MW), the rate and extent of dissolution and solution rheology of oat β-glucan are key factors in determining the physiological function of oat-containing foods. The structure and properties of oat β-glucan vary between species and varieties of oats, and are also affected by the growing and storage conditions and processing of oat grain. In addition, the extraction and analysis methods may also contribute to the variations in the structure, MW, hydration and solution rheology of β-glucan obtained from different laboratories. Recent work has demonstrated that β-glucan solubility in foods depends on the source of the material and processing conditions; solubility may also be subject to changes during food preparation and storage (such as freezing). In conclusion, both the amount and MW of β-glucan that are solubilised in the GIT need to be considered when assessing the blood-glucose and cholesterol-lowering properties of oat-containing foods.

Coffee is a relatively rich source of chlorogenic acids (CGA), which, as other polyphenols, have been postulated to exert preventive effects against CVD and type 2 diabetes. As a considerable proportion of ingested CGA reaches the large intestine, CGA may be capable of exerting beneficial effects in the large gut. Here, we utilise a stirred, anaerobic, pH-controlled, batch culture fermentation model of the distal region of the colon in order to investigate the impact of coffee and CGA on the growth of the human faecal microbiota. Incubation of coffee samples with the human faecal microbiota led to the rapid metabolism of CGA (4 h) and the production of dihydrocaffeic acid and dihydroferulic acid, while caffeine remained unmetabolised. The coffee with the highest levels of CGA (P< 0·05, relative to the other coffees) induced a significant increase in the growth of Bifidobacterium spp. relative to the control vessel at 10 h after exposure (P< 0·05). Similarly, an equivalent quantity of CGA (80·8 mg, matched with that in high-CGA coffee) induced a significant increase in the growth of Bifidobacterium spp. (P< 0·05). CGA alone also induced a significant increase in the growth of the Clostridium coccoides–Eubacteriumrectale group (P< 0·05). This selective metabolism and subsequent amplification of specific bacterial populations could be beneficial to host health.