Publications by authors named "Ian A Macdonald"

Malnutrition is present in most countries of the world. This ranges from general undernutrition due to insufficient food, or poor-quality diets low in some essential nutrients, to overnutrition and obesity with energy-rich but nutrient-poor diets. The fundamental aim of dietary recommendations is to prevent deficiency diseases, and the assumptions which underpin these recommendations need to be understood when considering what advice to give to the general public or individual patients.

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Objective: Sarcopenic-obesity (SO) is characterized by the concomitant presence of low muscle mass and high adiposity. This study explores the association of body composition and SO phenotypes with cognitive function in older adults.

Methods: Cross-sectional data in older adults (≥60 years) from NHANES 1999-2002 and 2011-2014 were used.

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Article Synopsis
  • * Results showed a significant decline in insulin-stimulated leg glucose uptake and leg muscle volume after bed-rest, along with reduced myofibrillar protein synthesis and decreased muscle glycogen storage.
  • * After reintroducing exercise (short-term exercise-supplemented remobilization), the study aimed to assess potential improvements in muscle volume, protein turnover, and glucose uptake, but the effects of this remobilization were not detailed.
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Background: Meal pattern is a potential health determinant. Previously, mean values for properties of meal pattern, such as daily meal frequency, have been considered. Means, however, obscure variability between-day (irregular or chaotic eating).

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Background: Dietary sugars are often linked to the development of overweight and type 2 diabetes (T2D) but inconsistencies remain.

Objective: We investigated associations of added, free, and total sugars, and glycaemic index (GI) with indices of glucose metabolism (IGM) and indices of body fatness (IBF) during a 3-year weight loss maintenance intervention.

Design: The PREVIEW (PREVention of diabetes through lifestyle Intervention and population studies in Europe and around the World) study was a randomised controlled trial designed to test the effects of four diet and physical activity interventions, after an 8-week weight-loss period, on the incidence of T2D.

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Overnutrition, expressed as overweight and obesity, sometimes combined with inadequate micronutrient intake, coexists together with undernutrition as the major threats of malnutrition in children. Appropriate growth and metabolism of children have been extensively studied as to their association with future metabolic diseases. It is appreciated that early growth is controlled via the biochemical pathways that support organ and tissue growth and development, energy release from dietary intake, and production and release of hormones and growth factors regulating the biochemical processes.

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Article Synopsis
  • - The study aimed to investigate how HbA (hemoglobin A1c) and glucose-related factors influence weight loss and blood sugar changes after an 8-week low energy diet in people with overweight and pre-diabetes conditions.
  • - In a sample of 2,178 individuals, neither HbA levels nor certain glucose measures correlated with changes in body weight after the diet; however, factors like higher body weight and insulin levels were linked to improved fasting glucose levels.
  • - The findings suggest that while HbA and glucose do not predict short-term weight loss success, they may affect metabolic responses to rapid weight loss, highlighting the roles of inflammation and body fat in these processes.
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Background & Aims: It is unclear if dietary adjustments to maintain energy balance during reduced physical activity can offset inactivity-induced reductions in insulin sensitivity and glucose disposal to produce normal daily glucose concentrations and meal responses. Therefore, the aim of the present study was to examine the impact of long-term physical inactivity (60 days of bed rest) on daily glycemia when in energy balance.

Methods: Interstitial glucose concentrations were measured using Continuous Glucose Monitoring Systems (CGMS) for 5 days before and towards the end of bed rest in 20 healthy, young males (Age: 34 ± 8 years; BMI: 23.

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Background: Owing to its role in glucose homeostasis, liver glycogen concentration ([LGly]) can be a marker of altered metabolism seen in disorders that impact the health of children. However, there is a paucity of normative data for this measure in children to allow comparison with patients, and time-course assessment of [LGly] in response to feeding has not been reported. In addition, carbon-13 magnetic resonance spectroscopy (C-MRS) is used extensively in research to assess liver metabolites in adult health and disease noninvasively, but similar measurements in children are lacking.

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There is interest in the impact that dietary interventions can have on preventing the transition from insulin resistance to type 2 diabetes, including a suggestion that the bioactive components of cocoa may enhance fasting insulin sensitivity. However, a role for cocoa flavanols (CF) in reducing insulin resistance in the insulin-stimulated state, an important risk factor for cardiovascular disease, is unresolved. This study investigated whether CF consumption improved whole-body insulin-mediated glucose uptake ('M') in females with overweight/obesity, using a randomized, double-blinded, placebo-controlled, parallel-group design.

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Article Synopsis
  • Scientists added seaweed-derived alginate to a type of feeding for patients who can't eat normally, hoping it would make digestion better and reduce problems like diarrhea and a poor appetite.
  • In a study with 12 healthy guys, they compared two types of feeds: one with alginate and one without, and they checked how it affected their stomachs and intestines using MRI and other tests.
  • The alginate feed made the stomach contents gel up a bit and helped with water levels in the intestines, but also changed how some hormones that affect hunger and blood sugar worked.
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The expression of genetic information is tightly controlled by chromatin regulatory proteins, including those in the heterochromatin gene repression family. Many of these regulatory proteins work together on the chromatin substrate to precisely regulate gene expression during mammalian development, giving rise to many different tissues in higher organisms from a fixed genomic template. Here we identify and characterize the interactions of two related heterochromatin regulatory proteins, heterochromatin protein 1 alpha (HP1α) and M-phase phosphoprotein 8 (MPP8), with hepatoma-derived growth factor-related protein 2 (HRP2).

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Background: Bed rest (BR) reduces whole-body insulin-stimulated glucose disposal (GD) and alters muscle fuel metabolism, but little is known about metabolic adaptation from acute to chronic BR nor the mechanisms involved, particularly when volunteers are maintained in energy balance.

Methods: Healthy males (n = 10, 24.0 ± 1.

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Objective: To examine whether the effect of a 3-year lifestyle intervention on body weight and cardiometabolic risk factors differs by prediabetes metabolic phenotype.

Research Design And Methods: This post hoc analysis of the multicenter, randomized trial, PREVention of diabetes through lifestyle interventions and population studies In Europe and around the World (PREVIEW), included 1,510 participants with prediabetes (BMI ≥25 kg ⋅ m-2; defined using oral glucose tolerance tests). Of these, 58% had isolated impaired fasting glucose (iIFG), 6% had isolated impaired glucose tolerance (iIGT), and 36% had IFG+IGT; 73% had normal hemoglobin A1c (HbA1c; <39 mmol ⋅ mol-1) and 25% had intermediate HbA1c (39-47 mmol ⋅ mol-1).

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Aims/hypothesis: Lifestyle interventions are the first-line treatment option for body weight and cardiometabolic health management. However, whether age groups or women and men respond differently to lifestyle interventions is under debate. We aimed to examine age- and sex-specific effects of a low-energy diet (LED) followed by a long-term lifestyle intervention on body weight, body composition and cardiometabolic health markers in adults with prediabetes (i.

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Background & Aims: Low-energy diet replacement is an effective tool to induce large and rapid weight loss and improve metabolic health, but in the long-term individuals often experience significant weight regain. Little is known about the role of animal-based foods in weight maintenance and metabolic health. We aimed to examine longitudinal associations of animal-based foods with weight maintenance and glycaemic and cardiometabolic risk factors.

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Behavioural responses to hypoglycaemia require coordinated recruitment of broadly distributed networks of interacting brain regions. We investigated hypoglycaemia-related changes in brain connectivity in people without diabetes (ND) and with type 1 diabetes with normal (NAH) or impaired (IAH) hypoglycaemia awareness. Two-step hyperinsulinaemic hypoglycaemic clamps were performed in 14 ND, 15 NAH and 22 IAH participants.

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Due to the observations of weight loss at high altitude, normobaric hypoxia has been considered as a method of weight loss in obese individuals. With this regard, the aim of the present study was to determine the effect of hypoxia on metabolism in men with excess weight. Eight men living with excess weight (125.

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Plant-based diets are recommended by dietary guidelines. This secondary analysis aimed to assess longitudinal associations of an overall plant-based diet and specific plant foods with weight-loss maintenance and cardiometabolic risk factors. Longitudinal data on 710 participants (aged 26-70 years) with overweight or obesity and pre-diabetes from the 3-year weight-loss maintenance phase of the PREVIEW intervention were analyzed.

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This study was performed to evaluate the profile of overweight individuals with pre-diabetes enrolled in PREVIEW who were unable to achieve a body weight loss of ≥8% of the baseline value in response to a 2-month low-energy diet (LED). Their baseline profile reflected potential stress-related vulnerability that predicted a reduced response of body weight to a LED programme. The mean daily energy deficit maintained by unsuccessful weight responders of both sexes was less than the estimated level in successful female (656 vs.

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Individuals with pre-diabetes are commonly overweight and benefit from dietary and physical activity strategies aimed at decreasing body weight and hyperglycemia. Early insulin resistance can be estimated the triglyceride glucose index {TyG = Ln [TG (mg/dl) × fasting plasma glucose (FPG) (mg/dl)/2]} and the hypertriglyceridemic-high waist phenotype (TyG-waist), based on TyG x waist circumference (WC) measurements. Both indices may be useful for implementing personalized metabolic management.

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Synaptic plasticity processes, which underlie learning and memory formation, require RNA to be translated local to synapses. The synaptic tagging hypothesis has previously been proposed to explain how mRNAs are available at specific activated synapses. However how RNA is regulated, and which transcripts are silenced or processed as part of the tagging process is still unknown.

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Background: Evidence is emerging that interdaily meal pattern variability potentially affects response such as thermic effect of food (TEF), macronutrient metabolism, and appetite.

Objectives: To investigate the effect of irregular meal pattern on TEF, glucose, insulin, lipid profile, and appetite regulation in women who are overweight or with obesity and confirmed insulin resistance.

Design: In a randomized crossover trial, 9 women [mean ± SD BMI (in kg/m2): 33.

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Background: Observed associations of high-protein diets with changes in insulin resistance are inconclusive.

Objectives: We aimed to assess associations of changes in both reported and estimated protein (PRep; PEst) and energy intake (EIRep; EIEst) with changes in HOMA-IR, glycated hemoglobin (HbA1c), and BMI (in kg/m2), in 1822 decreasing to 833 adults (week 156) with overweight and prediabetes, during the 3-y PREVIEW (PREVention of diabetes through lifestyle intervention and population studies In Europe and around the World) study on weight-loss maintenance. Eating behavior and measurement errors (MEs) of dietary intake were assessed.

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