Alison Parrett

Bio: Alison Parrett is an academic researcher from University of Glasgow. The author has contributed to research in topics: Breast feeding & Weaning. The author has an hindex of 13, co-authored 29 publications receiving 727 citations. Previous affiliations of Alison Parrett include Salisbury University.

Intestinal flora during the first months of life: new perspectives.

Abstract: Increasing awareness that the human intestinal flora is a major factor in health and disease has led to different strategies to manipulate the flora to promote health The complex microflora of the adult is difficult to change in the long term There is greater impact of diet on the infant microflora Manipulation of the flora particularly with probiotics has shown promising results in the prevention and treatment of diarrhoea and allergy Before attempting to change the flora of the infant population in general, a greater understanding of the gut bacterial colonisation process is required The critical stages of gut colonisation are after birth and during weaning Lactic acid bacteria dominate the flora of the breast-fed infant The formula-fed infant has a more diverse flora The faeces of the breast-fed infant contain mainly acetic and lactic acid whereas the formula fed-infant has mainly acetic and propionic acid Butyric acid is not a significant component in either group The formula-fed infant also has higher faecal ammonia and other potentially harmful bacterial products The composition of the microflora diversifies shortly before and particularly after weaning The flora of the formula-fed infant develops more quickly than that of the breast-fed infant Before embarking on any strategy to change the flora, the following questions should be considered: Should we retain a breast-fed style flora with limited ability to ferment complex carbohydrates? Can pro- and prebiotics achieve a flora with adult characteristics but with more lactic acid bacteria in weaned infants? Are there any health risks associated with such manipulations of the flora?

Faecal short chain fatty acids in breast-fed and formula-fed babies

Abstract: Edwards CA, Parrett AM, Balmer SE, Wharton BA. Faecal short chain fatty acids in breast-fed and formula-fed babies. Acta Paediatr 1994;83:459–62. Stockholm. ISSN 0803–5253 The intestinal flora of breast-fed infants differs from that of formula-fed infants. It is thought that this difference in flora may be one important reason why breast-fed babies suffer less from gastrointestinal disease. Differences in intestinal flora are reflected in the profile of faecal short chain fatty acids (SCFA). Very little is known about faecal concentrations of SCFA in babies fed breast milk or infant formula. In this study, faecal SCFA were measured in babies at two and four weeks of age who had been either exclusively breast fed or bottle fed from birth. There was no significant difference in total faecal SCFA concentrations between breast-fed and formula-fed babies when lactate was included. The formula-fed group, however, had less lactic acid and higher concentrations of propionic and n-buytric acids than breast-fed babies. Very few babies had significant levels of n-butyric acid, although this SCFA is believed to be important for the health of the colonic mucosa of adults.

Nutritional content of infant commercial weaning foods in the UK

Abstract: Background and aims Health professionals are frequently asked to advise on aspects of complementary feeding. This study aimed to describe the types of commercial infant foods available in the UK and provide an overview of their taste, texture and nutritional content in terms of energy, protein, carbohydrates, fat, sugar, iron, sodium and calcium. Method All infant foods produced by four main UK manufacturers and two more specialist suppliers were identified during October 2010–February 2011. Nutritional information for each product was collected from manufacturers’ websites, products in store and via direct email enquiry. Results Of the 479 products identified in this study 364 (79%) were ready-made spoonable foods; 44% (201) were aimed at infants from 4 months, and 65% of these were sweet foods. The mean (SD) energy content of ready-made spoonable foods was 282 (59) kJ per 100 g, almost identical to breast milk (283(16) kJ per 100 g). Similar spoonable family foods were more nutrient dense than commercial foods. Commercial finger foods were more energy dense, but had very high sugar content. Conclusions The UK infant food market mainly supplies sweet, soft, spoonable foods targeted from age 4 months. The majority of products had energy content similar to breast milk and would not serve the intended purpose of enhancing the nutrient density and diversity of taste and texture in infants’ diets.

In vitro fermentation of carbohydrate by breast fed and formula fed infants

Abstract: Unabsorbed carbohydrates are fermented by colonic bacteria to short chain fatty acids (SCFA) which are rapidly absorbed, salvaging energy and reducing stool output There are marked differences between the faecal flora and SCFA of breast fed (BF) and formula fed (FF) infants which may be related to the higher incidence of diarrhoea in FF infants Part of this effect may be caused by a difference in the ability of the microflora to ferment carbohydrate To test the hypothesis that BF and FF have different fermentation capacities for simple and complex carbohydrates, in vitro cultures of faeces from healthy infants (2-10 weeks; 11 BF, 11 FF) containing glucose, lactose, raftilose (a fructo-oligosaccharide), or soybean polysaccharide were incubated anaerobically Results were compared with those of adult faecal cultures using the same carbohydrates Cultures of faeces from BF and FF infants produced comparable amounts of total SCFA in all cultures These cultures produced less SCFA than those from adult faeces and produced very little SCFA from complex carbohydrate BF cultures produced more acetic acid than FF in all cultures, whereas FF cultures produced more propionate with sugars and more butyrate with raftilose Both groups of infants produced less butyrate than adults in all cultures Thus it is unlikely that a lower ability to ferment carbohydrate is a major cause of increased risk of diarrhoea in FF fed infants but individual SCFA production may be important

Dietary fibre in infancy and childhood

Abstract: There is very little evidence for the effects of dietary fibre in young children and current dietary guidelines are based on assumptions and data extrapolated from studies in adults. The first years of life may be critical for the establishment of a healthy colonic microflora, as well as good eating habits. The lack of clear and well-founded guidelines for the intake of dietary fibre in childhood may hinder both factors. The fears that a high-fibre diet in children < 5 years of age will lead to growth faltering and mineral imbalance are not well supported in the literature, especially for children in the developed world. Indeed, with the rising levels of obesity, fibre intake may be of benefit in reducing energy intake. A low-fibre diet may also be implicated in the aetiology of childhood constipation and appendicitis. The latest proposals for the definition of dietary fibre include oligosaccharides, which may act as prebiotics. There are potential health benefits of including oligosaccharides in the diets of infants and children, but more research is needed to consider the long-term effects. The immature intestine of the infant may also result in a greater amount of starch entering the colon during weaning, and this starch would now be considered dietary fibre under the new definitions. Much new research is needed to allow adequate recommendations for the intake of dietary fibre in childhood based on data collected in appropriate age-groups.

Short-Chain Fatty Acids and Human Colonic Function: Roles of Resistant Starch and Nonstarch Polysaccharides

Abstract: Resistant starch (RS) is starch and products of its small intestinal digestion that enter the large bowel. It occurs for various reasons including chemical structure, cooking of food, chemical modification, and food mastication. Human colonic bacteria ferment RS and nonstarch polysaccharides (NSP; major components of dietary fiber) to short-chain fatty acids (SCFA), mainly acetate, propionate, and butyrate. SCFA stimulate colonic blood flow and fluid and electrolyte uptake. Butyrate is a preferred substrate for colonocytes and appears to promote a normal phenotype in these cells. Fermentation of some RS types favors butyrate production. Measurement of colonic fermentation in humans is difficult, and indirect measures (e.g., fecal samples) or animal models have been used. Of the latter, rodents appear to be of limited value, and pigs or dogs are preferable. RS is less effective than NSP in stool bulking, but epidemiological data suggest that it is more protective against colorectal cancer, possibly via butyrate. RS is a prebiotic, but knowledge of its other interactions with the microflora is limited. The contribution of RS to fermentation and colonic physiology seems to be greater than that of NSP. However, the lack of a generally accepted analytical procedure that accommodates the major influences on RS means this is yet to be established.

New hypotheses for the health-protective mechanisms of whole-grain cereals: what is beyond fibre?

Abstract: Epidemiological studies have clearly shown that whole-grain cereals can protect against obesity, diabetes, CVD and cancers. The specific effects of food structure (increased satiety, reduced transit time and glycaemic response), fibre (improved faecal bulking and satiety, viscosity and SCFA production, and/or reduced glycaemic response) and Mg (better glycaemic homeostasis through increased insulin secretion), together with the antioxidant and anti-carcinogenic properties of numerous bioactive compounds, especially those in the bran and germ (minerals, trace elements, vitamins, carotenoids, polyphenols and alkylresorcinols), are today well-recognised mechanisms in this protection. Recent findings, the exhaustive listing of bioactive compounds found in whole-grain wheat, their content in whole-grain, bran and germ fractions and their estimated bioavailability, have led to new hypotheses. The involvement of polyphenols in cell signalling and gene regulation, and of sulfur compounds, lignin and phytic acid should be considered in antioxidant protection. Whole-grain wheat is also a rich source of methyl donors and lipotropes (methionine, betaine, choline, inositol and folates) that may be involved in cardiovascular and/or hepatic protection, lipid metabolism and DNA methylation. Potential protective effects of bound phenolic acids within the colon, of the B-complex vitamins on the nervous system and mental health, of oligosaccharides as prebiotics, of compounds associated with skeleton health, and of other compounds such as alpha-linolenic acid, policosanol, melatonin, phytosterols and para-aminobenzoic acid also deserve to be studied in more depth. Finally, benefits of nutrigenomics to study complex physiological effects of the 'whole-grain package', and the most promising ways for improving the nutritional quality of cereal products are discussed.

Honor thy symbionts

Abstract: Our intestine is the site of an extraordinarily complex and dynamic environmentally transmitted consortial symbiosis. The molecular foundations of beneficial symbiotic host-bacterial relationships in the gut are being revealed in part from studies of simplified models of this ecosystem, where germ-free mice are colonized with specified members of the microbial community, and in part from comparisons of the genomes of members of the intestinal microbiota. The results emphasize the contributions of symbionts to postnatal gut development and host physiology, as well as the remarkable strategies these microorganisms have evolved to sustain their alliances. These points are illustrated by the human-Bacteroides thetaiotaomicron symbiosis. Interdisciplinary studies of the effects of the intestinal environment on genome structure and function should provide important new insights about how microbes and humans have coevolved mutually beneficial relationships and new perspectives about the foundations of our health.

Bacterial metabolism and health-related effects of galacto-oligosaccharides and other prebiotics

Abstract: Most studies involving prebiotic oligosaccharides have been carried out using inulin and its fructo-oligosaccharide (FOS) derivatives, together with various forms of galacto-oligosaccharides (GOS). Although many intestinal bacteria are able to grow on these carbohydrates, most investigations have demonstrated that the growth of bifidobacteria, and to a lesser degree lactobacilli, is particularly favoured. Because of their safety, stability, organoleptic properties, resistance to digestion in the upper bowel and fermentability in the colon, as well as their abilities to promote the growth of beneficial bacteria in the gut, these prebiotics are being increasingly incorporated into the Western diet. Inulin-derived oligosaccharides and GOS are mildly laxative, but can result in flatulence and osmotic diarrhoea if taken in large amounts. However, their effects on large bowel habit are relatively minor. Although the literature dealing with the health significance of prebiotics is not as extensive as that concerning probiotics, considerable evidence has accrued showing that consumption of GOS and FOS can have significant health benefits, particularly in relation to their putative anti-cancer properties, influence on mineral absorption, lipid metabolism, and anti-inflammatory and other immune effects such as atopic disease. In many instances, prebiotics seem to be more effective when used as part of a synbiotic combination.

Gut microbiota composition and development of atopic manifestations in infancy: the KOALA Birth Cohort Study

Abstract: Background and aims: Perturbations in intestinal microbiota composition due to lifestyle changes may be involved in the development of atopic diseases. We examined gut microbiota composition in early infancy and the subsequent development of atopic manifestations and sensitisation. Methods: The faeces of 957 infants aged 1 month and participating in the KOALA Birth Cohort Study were analysed using quantitative real-time PCR. Information on atopic symptoms (eczema, wheeze) and potential confounders was acquired through repeated questionnaires. Total and specific IgE were measured in venous blood samples collected during home visits when the infant was 2 years old. During these home visits a clinical diagnosis of atopic dermatitis was made according to the UK-Working Party criteria. Results: The presence of Escherichia coli was associated with a higher risk of developing eczema (OR adj = 1.87; 95% CI 1.15 to 3.04), this risk being increased with increasing numbers of E coli (p for trend = 0.016). Infants colonised with Clostridium difficile were at higher risk of developing eczema (OR adj = 1.40; 95% CI 1.02 to 1.91), recurrent wheeze (OR adj = 1.75; 95% CI 1.09 to 2.80) and allergic sensitisation (OR adj = 1.54; 95% CI 1.02 to 2.31). Furthermore, the presence of C difficile was also associated with a higher risk of a diagnosis of atopic dermatitis during the home visit (OR adj = 1.73; 95% CI 1.08 to 2.78). Conclusion: This study demonstrates that differences in gut microbiota composition precede the development of atopy. Since E coli was only associated with eczema and C difficile was associated with all atopic outcomes, the underlying mechanisms explaining these association may be different.