Effect of prebiotics on the human gut microbiota of elderly persons

The colonic microbiota undergoes certain age related changes that may affect health. For example, above the age of 55–65 y, populations of bifidobacteria are known to decrease markedly. Bifidobacteria are known inhibitors of pathogenic microbes and a decrease in their activities may increase susceptibility to infections. There is therefore interest in trying to reverse their decline in aged persons. As the gut microbiota responds to dietary intervention, both probiotics and prebiotics have been tested in this regard. Probiotics are live microbes in the diet, whereas prebiotics are fermentable ingredients that specifically target components of the indigenous microbiota seen to be beneficial. We have published a recent paper demonstrating that prebiotic galactooligosaccharides can exert power effects upon bifidobacteria in the gut flora of elderly persons (both in vivo and in vitro). This addendum summarizes research that led up to this study and discusses the possible impact of prebiotics in impacting upon the gut health of aged persons.

Stable isotopes and diet: their contribution to Romano-British research

The study of stable isotopes surviving in human bone is fast becoming a standard response in the analysis of cemeteries. Reviewing the state of the art for Roman Britain, the author shows clear indications of a change in diet (for the better) following the Romanisation of Iron Age Britain—including more seafood, and more nutritional variety in the towns. While samples from the bones report an average of diet over the years leading up to an individual's death, carbon and nitrogen isotope signatures taken from the teeth may have a biographical element—capturing those childhood dinners. In this way migrants have been detected—as in the likely presence of Africans in Roman York. While not unexpected, these results show the increasing power of stable isotopes to comment on populations subject to demographic pressures of every kind.

The impact of substituting SFA in dairy products with MUFA or PUFA on CVD risk: evidence from human intervention studies

With the substantial economic and social burden of CVD, the need to modify diet and lifestyle factors to reduce risk has become increasingly important. Milk and dairy products, being one of the main contributors to SFA intake in the UK, are a potential target for dietary SFA reduction. Supplementation of the dairy cow's diet with a source of MUFA or PUFA may have beneficial effects on consumers' CVD risk by partially replacing milk SFA, thus reducing entry of SFA into the food chain. A total of nine chronic human intervention studies have used dairy products, modified through bovine feeding, to establish their effect on CVD risk markers. Of these studies, the majority utilised modified butter as their primary test product and used changes in blood cholesterol concentrations as their main risk marker. Of the eight studies that measured blood cholesterol, four reported a significant reduction in total and LDL-cholesterol (LDL-C) following chronic consumption of modified milk and dairy products. Data from one study suggested that a significant reduction in LDL-C could be achieved in both the healthy and hypercholesterolaemic population. Thus, evidence from these studies suggests that consumption of milk and dairy products with modified fatty acid composition, compared with milk and dairy products of typical milk fat composition, may be beneficial to CVD risk in healthy and hypercholesterolaemic individuals. However, current evidence is insufficient and further work is needed to investigate the complex role of milk and cheese in CVD risk and explore the use of novel markers of CVD risk.

Weaning diet induces sustained metabolic phenotype shift in the pig and influences host response to Bifidobacterium lactis NCC2818

Background The process of weaning causes a major shift in intestinal microbiota and is a critical period for developing appropriate immune responses in young mammals.Objective To use a new systems approach to provide an overview of host metabolism and the developing immune system in response to nutritional intervention around the weaning period.Design Piglets (n=14) were weaned onto either an egg-based or soya-based diet at 3 weeks until 7 weeks, when all piglets were switched onto a fish-based diet. Half the animals on each weaning diet received Bifidobacterium lactis NCC2818 supplementation from weaning onwards. Immunoglobulin production from immunologically relevant intestinal sites was quantified and the urinary (1)H NMR metabolic profile was obtained from each animal at post mortem (11 weeks).Results Different weaning diets induced divergent and sustained shifts in the metabolic phenotype, which resulted in the alteration of urinary gut microbial co-metabolites, even after 4 weeks of dietary standardisation. B lactis NCC2818 supplementation affected the systemic metabolism of the different weaning diet groups over and above the effects of diet. Additionally, production of gut mucosa-associated IgA and IgM was found to depend upon the weaning diet and on B lactis NCC2818 supplementation.ConclusionThe correlation of urinary (1)H NMR metabolic profile with mucosal immunoglobulin production was demonstrated, thus confirming the value of this multi-platform approach in uncovering non-invasive biomarkers of immunity. This has clear potential for translation into human healthcare with the development of urine testing as a means of assessing mucosal immune status. This might lead to early diagnosis of intestinal dysbiosis and with subsequent intervention, arrest disease development. This system enhances our overall understanding of pathologies under supra-organismal control.

PASSCLAIM: diet-related cancer

The strongest markers presently available are precancerous lesions (e. g. polyps or aberrant crypt foci) in humans and precancerous lesions and tumours in animal models. The only marker that presently can be used for a 'reduction of disease risk' claim (type B) for food components is 'polyp recurrence'. Type B claims cannot be made on the basis of results in animal models. All of the other biomarkers examined presently lack validation against the 'true endpoint', the tumour, and thus cannot be used for type B claims. 'Reduction of disease risk' claims in the area of 'diet-related cancer' should be based primarily on human intervention studies using relevant/acceptable endpoints. An important area for future research will be the validation of these surrogate endpoints.

Salmon consumption during pregnancy alters fatty acid composition and secretory IgA concentration in human breast milk

Fish oil supplementation during pregnancy alters breast milk composition, but there is little information about the impact of oily fish consumption. We determined whether increased salmon consumption during pregnancy alters breast milk fatty acid composition and immune factors. Women (n = 123) who rarely ate oily fish were randomly assigned to consume their habitual diet or to consume 2 portions of farmed salmon per week from 20 wk of pregnancy until delivery. The salmon provided 3.45 g long-chain (LC) (n-3) PUFA/wk. Breast milk fatty acid composition and immune factors [soluble CD14, transforming growth factor-b (TGFb)1, TGFb2, and secretory IgA] were analyzed at 1, 5, 14, and 28 d postpartum (PP). Breast milk from the salmon group had higher proportions of EPA (80%), docosapentaenoic acid (30%), and DHA (90%) on d 5 PP compared with controls (P < 0.01). The LC (n-6) PUFA:LC (n-3) PUFA ratio was lower for the salmon group on all days of PP sampling (P < 0.004), although individual (n-6) PUFA proportions, including arachidonic acid, did not differ. All breast milk immune factors decreased between d 1 and 28 PP (P < 0.001). Breast milk secretory IgA (sIgA) was lower in the salmon group (d 1–28 PP; P = 0.006). Salmon consumption during pregnancy, at the current recommended intakes, increases the LC (n-3) PUFA concentration of breast milk in early lactation, thus improving the supply of these important fatty acids to the breast-fed neonate. The consequence of the lower breast milk concentration of sIgA in the salmon group is not clear.

Role of lipids in human nutrition

Fat is a major contributor to energy intake in most Western diets, supplying 35–40% of food energy. It is described as being ‘energy-dense’, because a gram of fat (9 kcal/g) yields more than twice as much metabolisable energy as a gram of either carbohydrate or protein (4 kcal/g). Most of the fat we consume in our diet is in the form of triacylglycerol (90-95%), with cholesterol and phospholipids making up the bulk of the remainder. Dietary advice invariably stresses the importance of fat reduction, yet fats have diverse roles in human nutrition. They are important as a source of energy, both for immediate utilisation by the body and in laying down a storage depot (adipose tissue) for later utilisation when food intake is reduced, they act as a vehicle for the ingestion and absorption of fat-soluble vitamins, and they have diverse structural and functional roles in the body. Cholesterol is also an essential component of cell membranes and is the precursor for synthesis of hormones. This chapter describes the structure, digestion, transport and functional properties of dietary fat in the body and explains the basis of associations between fat consumption and chronic disease.

Immune factors and fatty acid composition in human milk from river/lake, coastal and inland regions of China

Breast milk fatty acid composition may be affected by maternal diet during gestation and lactation. The influence of dietary and breast milk fatty acids on breast milk immune factors is poorly defined. We determined the fatty acid composition and immune factor concentrations of breast milk from women residing in river & lake, coastal, and inland regions of China, which differ in their consumption of lean fish and oily fish. Breast milk samples were collected on days 3 to 5 (colostrum), 14 and 28 post-partum and analysed for soluble CD14 (sCD14), transforming growth factor (TGF)-β1, TGF-β2, secretory immunoglobulin A (sIgA) and fatty acids. The fatty acid composition of breast milk differed between regions and with time post-partum. The concentrations of all four immune factors in breast milk decreased over time, with sCD14, sIgA and TGF-β1 being highest in colostrum in the river & lake region. Breast milk DHA and arachidonic acid (AA) were positively associated, and γ-linolenic acid and EPA negatively associated, with the concentrations of each of the four immune factors. In conclusion, breast milk fatty acids and immune factors differ between regions in China characterised by different patterns of fish consumption and change during the course of lactation. A higher breast milk DHA and AA concentration is associated with higher concentrations of immune factors in breast milk, suggesting a role for these fatty acids in promoting gastrointestinal and immune maturation of the infant.

Polyphenols in the diet: friend or foe?

Polyphenols are suggested to have human health benefits, yet debate still exists over their value in the diet. This review examines their efficacy and the effect of structural diversity on their reactivity and any implications this may have with respect to possible unfavourable adverse effects. We propose that polyphenols are of benefit to humans through dietary consumption, yet care should be taken over excessive consumption, particularly in some subgroups of the population, e.g. those on certain medications because of complex nutrient–drug interactions. Pharmaceutical application should be avoided until there is greater understanding of absorption and behaviour of polyphenols within the body.

Weaning diet induces sustained metabolic phenotype shift in the pig and influences host response to Bifidobacterium lactis NCC2818

Background: The process of weaning causes a major shift in intestinal microbiota and is a critical period for developing appropriate immune responses in young mammals. Objective: To use a new systems approach to provide an overview of host metabolism and the developing immune system in response to nutritional intervention around the weaning period. Design: Piglets (n¼14) were weaned onto either an eggbased or soya-based diet at 3 weeks until 7 weeks, when all piglets were switched onto a fish-based diet. Half the animals on each weaning diet received Bifidobacterium lactis NCC2818 supplementation from weaning onwards. Immunoglobulin production from immunologically relevant intestinal sites was quantified and the urinary 1H NMR metabolic profile was obtained from each animal at post mortem (11 weeks). Results: Different weaning diets induced divergent and sustained shifts in the metabolic phenotype, which resulted in the alteration of urinary gut microbial co-metabolites, even after 4 weeks of dietary standardisation. B lactis NCC2818 supplementation affected the systemic metabolism of the different weaning diet groups over and above the effects of diet. Additionally, production of gut mucosa-associated IgA and IgM was found to depend upon the weaning diet and on B lactis NCC2818 supplementation. Conclusion: The correlation of urinary 1H NMR metabolic profile with mucosal immunoglobulin production was demonstrated, thus confirming the value of this multiplatform approach in uncovering non-invasive biomarkers of immunity. This has clear potential for translation into human healthcare with the development of urine testing as a means of assessing mucosal immune status. This might lead to early diagnosis of intestinal dysbiosis and with subsequent intervention, arrest disease development. This system enhances our overall understanding of pathologies under supra-organismal control.

The effects of dietary nitrate on blood pressure and endothelial function: a review of human intervention studies.

Evidence has accumulated in recent years that suggests that nitrate from the diet, particularly vegetables, is capable of producing bioactive NO in the vasculature, following bioconversion to nitrite by oral bacteria. The aim of the present review was to consider the current body of evidence for potential beneficial effects of dietary nitrate on blood pressure and endothelial function, with emphasis on evidence from acute and chronic human intervention studies. The studies to date suggest that dietary nitrate acutely lowers blood pressure in healthy humans. An inverse relationship was seen between dose of nitrate consumed and corresponding systolic blood pressure reduction, with doses of nitrate as low as 3 mmol of nitrate reducing systolic blood pressure by 3 mmHg. Moreover, the current studies provide some promising evidence on the beneficial effects of dietary nitrate on endothelial function. In vitro studies suggest a number of potential mechanisms by which dietary nitrate and its sequential reduction to NO may reduce blood pressure and improve endothelial function, such as: acting as a substrate for endothelial NO synthase; increasing vasodilation; inhibiting mitochondrial reactive oxygen species production and platelet aggregation. In conclusion, the evidence for beneficial effects of dietary nitrate on blood pressure and endothelial function is promising. Further long-term randomised controlled human intervention studies assessing the potential effects of dietary nitrate on blood pressure and endothelial function are needed, particularly in individuals with hypertension and at risk of CVD.

The effects of flavonoid and other polyphenol consumption on cognitive performance: A systematic research review of human experimental and epidemiological studies

Literature reviews suggest flavonoids, a sub-class of polyphenols, are beneficial for cognition. This is the first review examining the effect of consumption of all polyphenol groups on cognitive function. Inclusion criteria were polyphenol vs. control interventions and epidemiological studies with an objective measure of cognitive function. Participants were healthy or mildly cognitively impaired adults. Studies were excluded if clinical assessment or diagnosis of Alzheimer’s disease, dementia, or cognitive impairment was the sole measure of cognitive function, or if the polyphenol was present with potentially confounding compounds such as caffeine (e.g. tea studies) or Ginkgo Biloba. 28 studies were identified; 4 berry juice studies, 4 cocoa studies, 13 isoflavone supplement studies, 3 other supplement studies, and 4 epidemiological surveys. Overall, 16 studies reported cognitive benefits following polyphenol consumption. Evidence suggests that consuming additional polyphenols in the diet can lead to cognitive benefits, however, the observed effects were small. Declarative memory and particularly spatial memory appear most sensitive to polyphenol consumption and effects may differ depending on polyphenol source. Polyphenol berry fruit juice consumption was most beneficial for immediate verbal memory, whereas isoflavone based interventions were associated with significant improvements for delayed spatial memory and executive function. Comparison between studies was hampered by methodological inconsistencies. Hence, there was no clear evidence for an association between cognitive outcomes and polyphenol dose response, duration of intervention, or population studied. In conclusion, however, the findings do imply that polyphenol consumption has potential to benefit cognition both acutely and chronically.

Diet and lifestyle in Bronze Age Northwest Spain: the collective burial of Cova do Santo

A multidisciplinary investigation of the collective burial of Cova do Santo is presented as a novel approach to understand daily life during the Bronze Age in Northwest Iberia. The research is focused on three main aspects: i) taphonomy and patterns of disposal, ii) paleopathology and -demography as indicators of health status and lifestyle, and iii) stable isotope analysis to reconstruct paleodiet and to investigate the timing of the introduction of millet to the Iberian Peninsula. Osteological analyses were performed on 64 bones (61 human and 3 animal); additionally, bone collagen was extracted from 15 samples (13 human and 2 animal) and analyzed for its carbon and nitrogen stable isotopes composition. The radiocarbon age of the human remains is consistent with the Middle Bronze Age (c. 1890 to 1600 cal BC). The recovered remains belonged to a minimum number of 14 individuals with an estimated age at death of forty years or younger. This relatively young age is in contrast to a high prevalence of degenerative joint disease in the group. The isotopic results suggest a very homogeneous diet, which was almost exclusively based on C3 plants and terrestrial animal products. Overall, the data suggest that the studied population belonged to a period prior to the introduction of spring or summer-grown crops such as millets. The collective burial from the cave of Cova de Santo, Galicia, currently represents the largest assemblage of prehistoric human remains from Northwest Spain and the relatively good preservation of the bones offers a unique opportunity to investigate daily life in Northern Iberia during the Bronze Age.

Isotopic examination of links between diet, social differentiation and DISH at the post-medieval Carmelite Friary of Aalst, Belgium

Stable isotope ratios (δ13C and δ15N) were measured in human burials from the post-medieval (16th–18th c. AD) Carmelite friary burial grounds at Aalst, a town in Flanders, Belgium. Dietary patterns of 39 adult individuals were analyzed, from a mixed monastic and lay population buried in three different locations, reflecting groups with differing social status. The data show significant variation in the consumption of perhaps meat, but certainly also marine protein between females and males. This result represents a remarkable continuity with medieval dietary patterns, suggesting that the social and economic changes of the early modern period had a limited effect on everyday life. When both sexes were examined together, individuals buried in the cloister garth consumed significantly less marine protein compared to people buried in the church, likely reflecting social stratification. No statistical differences were observed between isotopic values from the church and the cloister alley, suggesting a similarly diverse diet of the monastic part of the buried population and that of the richer lay population. Finally, the hypothesis that diffuse idiopathic skeletal hyperostosis (DISH) is linked to a diet rich in animal protein was tested. No systematic or statistically significant differences between pathological and non-pathological bones from the same individuals affected with DISH were observed, and no statistical differences were found between individuals with DISH and individuals without DISH

Diet rich in high glucoraphanin broccoli reduces plasma LDL cholesterol: evidence from randomised controlled trials

Cruciferous-rich diets have been associated with reduction in plasma LDL-cholesterol (LDL-C), which may be due to the action of isothiocyanates derived from glucosinolates that accumulate in these vegetables. This study tests the hypothesis that a diet rich in high glucoraphanin (HG) broccoli will reduce plasma LDL-C. METHODS AND RESULTS: One hundred and thirty volunteers were recruited to two independent double-blind, randomly allocated parallel dietary intervention studies, and were assigned to consume either 400 g standard broccoli or 400 g HG broccoli per week for 12 weeks. Plasma lipids were quantified before and after the intervention. In study 1 (37 volunteers), the HG broccoli diet reduced plasma LDL-C by 7.1% (95% CI: -1.8%, -12.3%, p = 0.011), whereas standard broccoli reduced LDL-C by 1.8% (95% CI +3.9%, -7.5%, ns). In study 2 (93 volunteers), the HG broccoli diet resulted in a reduction of 5.1% (95% CI: -2.1%, -8.1%, p = 0.001), whereas standard broccoli reduced LDL-C by 2.5% (95% CI: +0.8%, -5.7%, ns). When data from the two studies were combined the reduction in LDL-C by the HG broccoli was significantly greater than standard broccoli (p = 0.031). CONCLUSION: Evidence from two independent human studies indicates that consumption of high glucoraphanin broccoli significantly reduces plasma LDL-C