Tom Preston

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Isotope dilution and the assessment of body composition

Foreword [to a special issue of Rapid Communications in Mass Spectrometry]

No abstract available

In Vitro and in Vivo Evaluation of the Fermentability of Two Different Wheat-Derived Fibre Fractions

Annals of Nutrition and Metabolism, 2017

Applying isotope dilution to measure body composition

Feasibility of testing the medium-term impact of inulin on phenolic acids bioavailability in healthy overweight individuals

Proceedings of the Nutrition Society, 2020

IntroductionInteractions between polyphenols and non-digestible carbohydrates (NDC) can impact on... more IntroductionInteractions between polyphenols and non-digestible carbohydrates (NDC) can impact on polyphenolic metabolites bioavailability, including phenolic acids. The BLEND2 trial (NCT03840746) aims to study longer-term interactions of a flavonoid-rich food with/without NDC on microbiota metabolites and cardiometabolic markers. Trial feasibility using a bespoke food was tested.Material and MethodsThe soup was developed locally containing cherry tomatoes, tomato puree, red onion, fresh lovage, with/without the NDC inulin (10g), but improved and processed with Campden BRI, Chipping Campden, UK. The final product (~400g/ tin) was evaluated with VAS scales (0–10) for appearance, smell, taste and overall palatability, and flavonoid content evaluated using liquid chromatography-mass spectrometry. The 3-arm parallel randomised blinded design (control soup, soup + inulin, habitual diet control) recruited self-reported healthy participants (BMI > 25, 40–70y) with urine, blood, faecal s...

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Neural correlates of working memory function in pediatric cancer survivors treated with chemotherapy: an fMRI study

NMR in Biomedicine, 2020

The goal of this study is to investigate the neural correlates of working memory function associa... more The goal of this study is to investigate the neural correlates of working memory function associated with chemotherapy in pediatric cancer survivors using event-related functional MRI (fMRI) analysis. Fifteen pediatric cancer survivors treated with chemotherapy and 15 healthy controls were studied. Blood oxygenation level dependent (BOLD) fMRI was acquired. A visual n-back task was used to test working memory function during the fMRI scan. Responses were recorded via an MRI compatible button box for analysis. fMRI scans were analyzed using statistical parametric mapping software. All statistics were corrected for multiple comparisons by false discovery rate, with p < 0.05 as significance. Patients however gave more incorrect responses (p < 0.05), more no responses (p < 0.05), and longer response times (p < 0.05) compared with healthy controls. Correct responses generated significantly lower BOLD responses in the posterior cingulate for pediatric cancer survivors compared with controls (p < 0.05). Incorrect responses generated significantly greater BOLD responses in the angular gyrus in survivors (p < 0.05), and no response trials generated greater BOLD responses within the superior parietal lobule (p < 0.05) compared with controls. Working memory impairment appears to be due to an inability to manipulate information and to retrieve information from memory. The ability to delineate the affected neural circuits associated with chemotherapy-induced cognitive impairment could inform treatment strategies, identify patients at high risk of developing cognitive deficits, and pre-emptively tailor behavioral enrichment to overcome specific cognitive deficits. K E Y W O R D S acute lymphoblastic leukemia, blood oxygenation level dependent (BOLD) fMRI, chemobrain, cognitive impairment, cognitive late effects, functional MRI, n-back tasks 1 | INTRODUCTION There are 16 000 new diagnoses of cancer in children from birth to 21 years old and 450 000 pediatric cancer survivors in the United States in 2018. 1 The number of survivors has been steadily rising in recent years and will likely continue to rise due to increased incidence of childhood Abbreviations: ALL, acute lymphoblastic leukemia; BOLD, blood oxygenation level dependent; fMRI, functional MRI; FOV, field of view; MNI, Montreal Neurological Institute; MPRAGE, magnetization prepared rapid gradient echo; TE, time to echo; TR, time to repetition.

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Effects of Inulin Propionate Ester Incorporated into Palatable Food Products on Appetite and Resting Energy Expenditure: A Randomised Crossover Study

Nutrients, 2019

Supplementation with inulin-propionate ester (IPE), which delivers propionate to the colon, suppr... more Supplementation with inulin-propionate ester (IPE), which delivers propionate to the colon, suppresses ad libitum energy intake and stimulates the release of satiety hormones acutely in humans, and prevents weight gain. In order to determine whether IPE remains effective when incorporated into food products (FP), IPE needs to be added to a widely accepted food system. A bread roll and fruit smoothie were produced. Twenty-one healthy overweight and obese humans participated. Participants attended an acclimatisation visit and a control visit where they consumed un-supplemented food products (FP). Participants then consumed supplemented-FP, containing 10 g/d inulin or IPE for six days followed by a post-supplementation visit in a randomised crossover design. On study visits, supplemented-FP were consumed for the seventh time and ad libitum energy intake was assessed 420 min later. Blood samples were collected to assess hormones and metabolites. Resting energy expenditure (REE) was meas...

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$Research paper thumbnail of {"__content__"=>"The effect of L-rhamnose on intestinal transit time, short chain fatty acids and appetite regulation: a pilot human study using combined CO/H breath tests.", "sup"=>{"__content__"=>"13"}, "sub"=>[{"__content__"=>"2"}, {"__content__"=>"2"}]}$

{"__content__"=>"The effect of L-rhamnose on intestinal transit time, short chain fatty acids and appetite regulation: a pilot human study using combined CO/H breath tests.", "sup"=>{"__content__"=>"13"}, "sub"=>[{"__content__"=>"2"}, {"__content__"=>"2"}]}

Journal of breath research, Jan 6, 2018

The appetite-regulating effects of non-digestible carbohydrates (NDC) have in part previously bee... more The appetite-regulating effects of non-digestible carbohydrates (NDC) have in part previously been attributed to their effects on intestinal transit rates as well as microbial production of short chain fatty acids (SCFA). Increased colonic production of the SCFA propionate has been shown to reduce energy intake and stimulate gut hormone secretion acutely in humans. We investigated the effect of the propiogenic NDC, L-rhamnose, on gastrointestinal transit times using a combined CO/H breath test. We hypothesised that L-rhamnose would increase plasma propionate leading to a reduction in appetite, independent of changes in gastrointestinal transit times. We used a dual C-octanoic acid/lactose C-ureide breath test combined with breath H to measure intestinal transit times following the consumption of 25 g d L-rhamnose, compared with inulin and cellulose, in 10 healthy humans in a randomised cross-over design pilot study. Gastric emptying (GE) and oro-caecal transit times (OCTTs) were der...

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The effects of dietary supplementation with inulin and inulin-propionate ester on hepatic steatosis in adults with non-alcoholic fatty liver disease

Diabetes, obesity & metabolism, Jan 11, 2018

The short chain fatty acid (SCFA) propionate, produced through fermentation of dietary fibre by t... more The short chain fatty acid (SCFA) propionate, produced through fermentation of dietary fibre by the gut microbiota, has been shown to alter hepatic metabolic processes that reduce lipid storage. We aimed to investigate the impact of raising colonic propionate production on hepatic steatosis in adults with non-alcoholic fatty liver disease (NAFLD). Eighteen adults were randomized to receive 20 g/d of an inulin-propionate ester (IPE), designed to deliver propionate to the colon, or an inulin control for 42 days in a parallel design. The change in intrahepatocellular lipid (IHCL) following the supplementation period was not different between the groups (P = 0.082), however, IHCL significantly increased within the inulin-control group (20.9% ± 2.9% to 26.8% ± 3.9%; P = 0.012; n = 9), which was not observed within the IPE group (22.6% ± 6.9% to 23.5% ± 6.8%; P = 0.635; n = 9). The predominant SCFA from colonic fermentation of inulin is acetate, which, in a background of NAFLD and a hepat...

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Stable Isotope Techniques in Human Nutrition Research: Concerted Action is Needed

Food and Nutrition Bulletin, 2002

Use of stable isotopes in applied nutrition has been a developing field for over 60 years. The pa... more Use of stable isotopes in applied nutrition has been a developing field for over 60 years. The past 20 years has seen improvements in computer and mass-spectrometer technology that has opened up even greater possibilities in the understanding of human metabolism. While improvements in technology can bring great opportunities, it can also cause problems if there is no consensus among the stable isotope user-community on standardization of new techniques and methods. Users of stable isotopes have traditionally been split into two groups; those who work with heavy isotopes (e.g., 58Fe, 70Zn) and those who work with light isotopes (e.g., 2H218O). Standardization issues have been addressed by the light isotope users and awareness of this type of problem is starting to emerge within the heavy isotope community.

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Carbohydrate dose influences liver and muscle glycogen oxidation and performance during prolonged exercise

Physiological reports, 2018

This study investigated the effect of carbohydrate (CHO) dose and composition on fuel selection d... more This study investigated the effect of carbohydrate (CHO) dose and composition on fuel selection during exercise, specifically exogenous and endogenous (liver and muscle) CHO oxidation. Ten trained males cycled in a double-blind randomized order on 5 occasions at 77% V˙O2max for 2 h, followed by a 30-min time-trial (TT) while ingesting either 60 g·h-1 (LG) or 75 g·h-113 C-glucose (HG), 90 g·h-1 (LGF) or 112.5 g·h-113 C-glucose-13 C-fructose ([2:1] HGF) or placebo. CHO doses met or exceed reported intestinal transporter saturation for glucose and fructose. Indirect calorimetry and stable mass isotope [13 C] tracer techniques were utilized to determine fuel use. TT performance was 93% "likely/probable" to be improved with LGF compared with the other CHO doses. Exogenous CHO oxidation was higher for LGF and HGF compared with LG and HG (ES > 1.34, P < 0.01), with the relative contribution of LGF (24.5 ± 5.3%) moderately higher than HGF (20.6 ± 6.2%, ES = 0.68). Increasing...

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Starvation Can Result From Inadequate Dietary Planning for a 50-Day Rowing Expedition

International journal of sports physiology and performance, Jan 14, 2016

Meeting the energy demands of prolonged arduous expeditions and endurance sport may be a signific... more Meeting the energy demands of prolonged arduous expeditions and endurance sport may be a significant barrier to success. Expedition rowing is associated with high levels of body mass loss, reflecting the challenge of meeting energy expenditure in this exacting environment. This study used the Doubly Labelled Water (DLW) technique to calculate the Total Energy Expenditure (TEE), and body composition changes of two 28-year-old healthy male athletes during a 50-day continuous and unsupported row around Great Britain. A measured dose of DLW was taken at the start of two separate study periods (days five to 19 and 34 to 48) followed by sequential urine collection, which was analysed on return to land. Mean TEE was 15.3MJ/day: Athlete 1 16.4MJ/day, Athlete 2 14.9MJ/day. Athlete 1 lost 11.2kg and Athlete 2 lost 14.9kg of body mass during the row. Average energy provision was 19.1MJ per 24-hour ration pack. These results highlight the difficulty of maintaining energy balance during expediti...

The diet-derived short chain fatty acid propionate improves beta-cell function in humans and stimulates insulin secretion from human islets in vitro

Diabetes, Obesity and Metabolism, 2016

The diet-derived short chain fatty acid propionate improves beta-cell function in humans and stim... more

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Spatio-seasonal variability of chromophoric dissolved organic matter absorption and responses to photobleaching in a large shallow temperate lake

Biogeosciences Discussions, 2016

The development and validation of remote sensing-based approaches for the retrieval of CDOM conce... more The development and validation of remote sensing-based approaches for the retrieval of CDOM concentrations requires a comprehensive understanding of the sources and magnitude of variability in the optical properties of dissolved material within lakes. In this study, spatial and seasonal variability in concentration and composition of CDOM and the origin of its variation was studied in Lake Balaton (Hungary), a large temperate shallow lake in central Europe. In addition, we investigated the effect of photobleaching on the optical properties of CDOM through in-lake incubation experiments. There was marked variability throughout the year in CDOM absorption in Lake Balaton (aCDOM (440) = 0.06–9.01 m−1). The highest values were consistently observed at the mouth of the main inflow (River Zala), which drains humic-rich material from the adjoining Kis-Balaton wetland, but CDOM absorption decreased rapidly towards the east where it was consistently lower and...

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Systemic availability and metabolism of colonic-derived short-chain fatty acids in healthy subjects: a stable isotope study

The Journal of Physiology, 2016

 SCFAs are bacterial metabolites produced during colonic fermentation of undigested carbohydrat... more  SCFAs are bacterial metabolites produced during colonic fermentation of undigested carbohydrates, such as dietary fibre and prebiotics, and could mediate the interaction between diet, the microbiota and the host.  We quantified the fraction of colonic administered SCFA that could be recovered in the systemic circulation, the fraction that was excreted via breath and urine and the fraction that was used as a precursor for glucose, cholesterol and fatty acids.  This information is essential to understand the molecular mechanisms by which SCFA beneficially affect physiological functions such as glucose and lipid metabolism and immune function.

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[Memorandum from Tom Preston, May 4, 1987]

Letter from Tom Preston to John Ed Allen, Frank Kemerer, Gerry O'Donovan, Rogers Redding, Wal... more

Daniel A. Abaye, Douglas J. Morrison and Tom Preston 2011 Strong anion exchange liquid chromatographic separation of protein amino acids for natural 13C-abundance determination by isotope ratio mass spectrometry

Rapid Communications in Mass Spectrometry, 2011

Increased colonic propionate reduces anticipatory reward responses in the human striatum to high-energy foods

The American journal of clinical nutrition, Jan 11, 2016

Short-chain fatty acids (SCFAs), metabolites produced through the microbial fermentation of nondi... more Short-chain fatty acids (SCFAs), metabolites produced through the microbial fermentation of nondigestible dietary components, have key roles in energy homeostasis. Animal research suggests that colon-derived SCFAs modulate feeding behavior via central mechanisms. In humans, increased colonic production of the SCFA propionate acutely reduces energy intake. However, evidence of an effect of colonic propionate on the human brain or reward-based eating behavior is currently unavailable. We investigated the effect of increased colonic propionate production on brain anticipatory reward responses during food picture evaluation. We hypothesized that elevated colonic propionate would reduce both reward responses and ad libitum energy intake via stimulation of anorexigenic gut hormone secretion. In a randomized crossover design, 20 healthy nonobese men completed a functional magnetic resonance imaging (fMRI) food picture evaluation task after consumption of control inulin or inulin-propionate...

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Formation of short chain fatty acids by the gut microbiota and their impact on human metabolism

Gut microbes, Jan 10, 2016

The formation of SCFA is the result of a complex interplay between diet and the gut microbiota wi... more The formation of SCFA is the result of a complex interplay between diet and the gut microbiota within the gut lumen environment. The discovery of receptors, across a range of cell and tissue types for which short chain fatty acids SCFA appear to be the natural ligands, has led to increased interest in SCFA as signaling molecules between the gut microbiota and the host. SCFA represent the major carbon flux from the diet through the gut microbiota to the host and evidence is emerging for a regulatory role of SCFA in local, intermediary and peripheral metabolism. However, a lack of well-designed and controlled human studies has hampered our understanding of the significance of SCFA in human metabolic health. This review aims to pull together recent findings on the role of SCFA in human metabolism to highlight the multi-faceted role of SCFA on different metabolic systems.

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Compounds and their effects on appetite control and insulin sensitivity

The invention provides a propionate inulin ester for the reduction of appetite, food intake and/o... more The invention provides a propionate inulin ester for the reduction of appetite, food intake and/or calorie intake and/or to improve insulin sensitivity in a subject, and for the treatment or prevention of obesity or diabetes. The invention also provides compositions comprising a propionate inulin ester, methods using propionate inulin esters, functional food containing propionate inulin ester and methods of making propionate inulin esters

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