Claire E. Berryman's research while affiliated with Florida State University and other places

Publications (79)

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Introduction Testosterone administration attenuates reductions in total body mass and lean mass during severe energy deficit (SED). Objectives This study examined the effects of testosterone administration on the serum metabolome during SED. Methods In a double-blind, placebo-controlled clinical trial, non-obese men were randomized to receive 200...
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Abstract The objective of this study was to determine metabolic and physiological differences between males with low testosterone (LT) versus those with normal testosterone (NT) following a period of severe energy deficit. In this secondary analysis, 68 male US Marines (mean ± SD, 24.6 ± 2.4 y) were dichotomized by testosterone concentration (< or...
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Objectives Aligning energy intake with circadian rhythms and extending periods of fasting within a 24-h cycle improves whole-body metabolism. However, it is unknown if these improvements are related to changes in intestinal nutrient absorption (i.e., digestibility). The primary objective of the DIGEST study is to determine the impact of early time-...
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Objectives Individuals who travel to high altitude (≥5,000 ft) are exposed to hypobaric hypoxic (HH) conditions (i.e., low pressure, low oxygen). Extended exposure to HH conditions often results in body weight loss. This body weight loss is the result of an increase in resting metabolic rate (RMR) due to alterations in the sympathetic and parasympa...
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Objectives The incidence of type 2 diabetes mellitus (T2D) continues to increase in the United States, and the treatment of T2D and associated cardiovascular complications creates a large economic burden. Diet plays an important role in the prevention and treatment of T2D, and studies have suggested high glycemic index (GI) foods, in moderate amoun...
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Objectives The lack of complete amino acid composition data in food composition databases has made determining population-wide amino acid intake difficult. This cross-sectional study characterizes habitual intakes of each amino acid and adherence to dietary requirements for each essential amino acid (EAA) by age, gender, and race/ethnicity in the U...
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Objectives Little is known about the relationships between habitual essential amino acid (EAA) intake and functional health in older US adults. This cross-sectional study investigates associations between usual EAA intakes and body composition, muscle strength, and physical function in US adults ≥65 y. Methods The Food and Nutrient Database for Di...
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Background Declines in iron status are frequently reported in those who regularly engage in strenuous physical activity. A possible reason for the declines in iron status with physical activity is increases in the iron regulatory hormone hepcidin, which functions to inhibit dietary iron absorption and can be induced by the inflammatory cytokine int...
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Context Effects of testosterone on integrated muscle protein metabolism and muscle mass during energy deficit are undetermined. Objective The objective was to determine the effects of testosterone on mixed-muscle protein synthesis (MPS), proteome-wide fractional synthesis rates (FSR), and skeletal muscle mass during energy deficit. Design This wa...
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Background Physical and psychological stress alter gut-brain axis activity, potentially causing intestinal barrier dysfunction that may, in turn, induce cognitive and mood impairments through exacerbated inflammation and blood brain barrier (BBB) permeability. These interactions are commonly studied in animals or artificial laboratory environments....
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Individuals sojourning at high altitude (≥2,500m) often develop acute mountain sickness (AMS). However, substantial unexplained inter-individual variability in AMS severity exists. Untargeted metabolomics assays are increasingly used to identify novel biomarkers of susceptibility to illness, and to elucidate biological pathways linking environmenta...
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Background Clinical administration of testosterone is widely used due to a variety of claimed physical and cognitive benefits. Testosterone administration is associated with enhanced brain and cognitive function, as well as mood, in energy-balanced males, although such relationships are controversial. However, the effects of testosterone administra...
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Background Effects of high protein (HP) diets and prolonged energy restriction (ER) on integrated muscle protein kinetics have not been determined. Objective The objective of this study was to measure protein kinetics in response to prolonged ER and HP on muscle protein synthesis (MPS; absolute rates of synthesis) and muscle protein breakdown (MPB...
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Background & Aims Protein intake is inversely associated with waist circumference and positively associated with HDL-cholesterol concentrations. However, the relationship between protein intake during specific eating occasions and cardiometabolic health is not well documented. This cross-sectional study measured protein intake at meals and combined...
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Background: The ergogenic effects of supplemental carbohydrate on aerobic exercise performance at high altitude (HA) may be modulated by acclimatization status. Longitudinal evaluation of potential performance benefits of carbohydrate supplementation in the same volunteers before and after acclimatization to HA have not been reported. Purpose: T...
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Testosterone supplementation during energy deficit promotes whole-body lean mass accretion, but the mechanisms underlying that effect remain unclear. To elucidate those mechanisms, skeletal muscle molecular adaptations were assessed from muscle biopsies collected before (Resting), 1 h (Post) and 6 h (Recovery) after exercise and a mixed meal (40 g...
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Zinc is an essential nutrient for humans; however, a sensitive biomarker to assess zinc status has not been identified. The objective of this study was to determine the reliability and sensitivity of zinc transporter and metallothionein (MT) genes in peripheral blood mononuclear cells (PBMCs) to zinc exposure ex vivo and to habitual zinc intake in...
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Objectives Hepcidin is a negative regulator of extracellular iron availability and dietary iron absorption. Previous studies have shown that hepcidin increases with prolonged endurance exercise, but not in those with low iron stores (serum ferritin <30 ng/mL). The objective of this study was to determine the plasma hepcidin response to exercise, co...
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Objectives The Dietary Guidelines for Americans (DGAs) recommend dietary patterns that limit added sugar, sodium, and saturated fat and emphasize nutrient-dense foods. It is unknown whether individuals who self-report adhering to a diet that alters nutrient intake are, in fact, meeting DGA recommendations. Objective: To compare dietary intakes and...
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Objectives Obesity is associated with increased hepatic de novo lipogenesis (DNL) and altered triglyceride (TG) turnover. A previous trial in male Sprague Dawley rats demonstrated that both energy restriction and higher protein diets downregulate hepatic DNL. It is unknown whether energy restriction and higher protein diets alter kinetic measures o...
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Objectives High protein (HP) diets during short-term energy restriction (ER) attenuate energy-mediated reductions in muscle protein synthesis (MPS). MPS-adaptive responses to HP diets during prolonged ER are not well described. This study examined the effects of prolonged ER and HP on MPS and the synthesis rates of numerous individual muscle protei...
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Objectives We reported that healthy males supplemented with testosterone gained lean body mass (LBM) during 28-d of energy deficit and 14 d of ad libitium feeding when measured by dual energy x-ray absorptiometry (DXA), but with no increase in muscle strength. We were unable to determine whether LBM gains were due to muscle mass accrual since DXA d...
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Objectives Short-term energy deficit reduces acute measures of mixed muscle protein synthesis (MPS) and suppresses the hypothalamic-pituitary axis and endogenous testosterone synthesis. We hypothesized that testosterone supplementation could mitigate the effects of energy deficit on MPS. We conducted a randomized, double-blind, placebo-controlled t...
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Objectives Tactical military personnel regularly undergo training and operations that place them under extreme physical and psychological stress. Severe negative energy balance is one stressor that occurs due to prolonged and strenuous physical exertion and limited access to food. During an energy deficit, the body predominately relies on fat store...
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Background: The erythropoietic cells in the bone marrow require iron to synthesize heme for incorporation into hemoglobin. Exposure to hypoxic conditions, such as extended sojourns to high altitude (HA), results in increased erythropoiesis and an increased physiological requirement for iron. In addition to increasing iron requirements, hypoxic cond...
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Background: The optimal macronutrient composition of the diet is controversial and many adults attempt to regulate the intake of specific macronutrients for various health-related reasons. Objective: The objective was to compare stability and ranges of intakes of different macronutrients across diverse adult populations in the USA and globally....
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Background Severe energy deficits cause interrelated reductions in testosterone and fat free mass. Testosterone supplementation may mitigate those decrements, but could also reduce circulating concentrations of the orexigenic hormone ghrelin thereby exacerbating energy deficit by suppressing appetite. Objective To determine whether testosterone su...
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Context Severe energy deprivation markedly inhibits erythropoiesis by restricting iron availability for hemoglobin synthesis. Objective The objective of this study was to determine whether testosterone supplementation during energy deficit increased indicators of iron turnover and attenuated the decline in erythropoiesis compared to placebo. Desi...
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Background: Severe energy deficits during military operations, produced by significant increases in exercise and limited dietary intake, result in conditions that degrade lean body mass and lower-body muscle function, which may be mediated by concomitant reductions in circulating testosterone. Methods: We conducted a three-phase, proof-of-concep...
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Objectives: Greater protein intakes have been associated with decreased weight, BMI, waist circumference (WC) and increased HDL-cholesterol (HDL-C) concentrations. However, the relationship between protein intake during specific eating occasions and metabolic health is not well described. This study measured protein intake at meals (breakfast, lun...
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Objectives: Military personnel are exposed to periods of energy deficit and stress, which is typically accompanied by reductions in testosterone concentrations and declines in iron status. Exogenous testosterone administration may increase erythropoiesis and iron availability.The objective of this study was to determine the effects of exogenous te...
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When sea‐level (SL) residents rapidly ascend to high altitude (HA), plasma volume (PV) decreases. A quantitative model for predicting individual %∆PV over the first 7 days at HA has recently been developed from the measurements of %∆PV in 393 HA sojourners. We compared the measured %∆PV with the %∆PV predicted by the model in 17 SL natives living 2...
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Ingesting protein and carbohydrate together during aerobic exercise suppresses the expression of specific skeletal muscle microRNA and promotes muscle hypertrophy. Determining whether there are independent effects of carbohydrate and protein on microRNA will allow for a clearer understanding of the mechanistic role microRNA serve in regulating skel...
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Hypobaric hypoxia, and dietary protein and fat intakes have been independently associated with an altered gastrointestinal (GI) environment and gut microbiota, but little is known regarding host-gut microbiota interactions at high altitude (HA) and the impact of diet macronutrient composition. This study aimed to determine the effect dietary protei...
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This study investigated how high-altitude (HA, 4300 m) acclimatization affected exogenous glucose oxidation during aerobic exercise. Sea-level (SL) residents (n = 14 men) performed 80-min, metabolically matched exercise ( V ˙ O2 ∼ 1.7 L/min) at SL and at HA < 5 h after arrival (acute HA, AHA) and following 22-d of HA acclimatization (chronic HA,...
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Intramuscular factors that modulate fat-free mass (FFM) loss in lowlanders exposed to energy deficit during high-altitude (HA) sojourns remain unclear. Muscle inflammation may contribute to FFM loss at HA by inducing atrophy and inhibiting myogenesis via the tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) and its receptor, fibrob...
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Background: Systematic analysis of dietary protein intake may identify demographic groups within the American population that are not meeting the Dietary Reference Intakes (DRIs). Objective: This cross-sectional study analyzed protein intake trends (2001-2014) and evaluated recent conformity to the DRIs (2011-2014) according to age, sex, and rac...
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Muscle loss at high altitude (HA) is attributable to energy deficit and a potential dysregulation of anabolic signaling. Exercise and protein ingestion can attenuate the effects of energy deficit on muscle at sea level (SL). Whether these effects are observed when energy deficit occurs at HA is unknown. To address this, muscle obtained from lowland...
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Karl, J. Philip, Renee E. Cole, Claire E. Berryman, Graham Finlayson, Patrick N. Radcliffe, Matthew T. Kominsky, Nancy E. Murphy, John W. Carbone, Jennifer C. Rood, Andrew J. Young, and Stefan M. Pasiakos. Appetite Suppression and Altered Food Preferences Coincide with Changes in Appetite-Mediating Hormones During Energy Deficit at High Altitude, B...
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In this 2-phase randomized controlled study, we examined whether consuming a higher-protein (HP) diet would attenuate fat-free mass (FFM) loss during energy deficit (ED) at high altitude (HA) in 17 healthy males (mean ± sd: 23 ± 6 yr; 82 ± 14 kg). During phase 1 at sea level (SL, 55 m), participants consumed a eucaloric diet providing standard prot...
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Background Consumption of almonds or dark chocolate and cocoa has favorable effects on markers of coronary heart disease; however, the combined effects have not been evaluated in a well‐controlled feeding study. The aim of this study was to examine the individual and combined effects of consumption of dark chocolate and cocoa and almonds on markers...
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Background: Almonds may increase circulating HDL cholesterol when substituted for a high-carbohydrate snack in an isocaloric diet, yet little is known about the effects on HDL biology and function. Objective: The objective was to determine whether incorporating 43 g almonds/d in a cholesterol-lowering diet would improve HDL subspecies and function,...
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Background: The physiological consequences of severe energy deficit include hypogonadism and the loss of fat-free mass. Prolonged energy deficit also impacts physical performance, mood, attentiveness, and decision-making capabilities. This study will determine whether maintaining a eugonadal state during severe, sustained energy deficit attenuates...
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Negative energy balance during military operations can be severe and result in significant reductions in fat-free mass (FFM). Consuming supplemental high-quality protein following such military operations may accelerate restoration of FFM. Body composition (dual-energy x-ray absorptiometry) and whole-body protein turnover (single-pool (15)N-alanine...
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Effects of environmental hypoxia on fat-free mass are well studied. Negative energy balance, increased nitrogen excretion and fat-free mass loss are commonly observed in lowlanders sojourning at high altitude. Reductions in fat-free mass can be minimized if energy consumption matches energy expenditure. However, in non-research settings, achieving...
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Background: Higher-protein diets are associated with decreased adiposity and greater HDL cholesterol than lower protein diets. Whether these benefits can be attributed to a specific protein source (i.e., nondairy animal, dairy, or plant) is unknown, and concerns remain regarding the impact of higher-protein diets on kidney function. Objective: T...
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Evidence consistently shows that almond consumption beneficially affects lipids and lipoproteins. Almonds, however, have not been evaluated in a controlled-feeding setting using a diet design with only a single, calorie-matched food substitution to assess their specific effects on cardiometabolic risk factors. In a randomized, 2-period (6 week/peri...
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Walnut consumption improves cardiovascular disease risk; however, to our knowledge, the contribution of individual walnut components has not been assessed. This study evaluated the acute consumption of whole walnuts (85 g), separated nut skins (5.6 g), de-fatted nutmeat (34 g), and nut oil (51 g) on postprandial lipemia, endothelial function, and o...