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Exercise can be both anabolic and catabolic for bone tissue. The temporal response of both bone formation and resorption following an acute bout of exercise is not well described. We assayed biochemical markers of bone and calcium metabolism for up to 3 days after military-relevant exercise. In randomized order, male (n=18) and female (n=2) Soldiers (mean±SD; 21.2±4.1 years) performed a 60-minute bout of load carriage (30% body mass; 22.4±3.7 kg) treadmill exercise (EXER) or a resting control trial (REST). Blood samples were collected following provision of a standardized breakfast before (PRE), after (POST) exercise/rest, 1 h, 2 h, and 4 h into recovery. Fasted samples were also collected at 0630 h on EXER and REST and for the next 3 mornings after EXER. Parathyroid hormone and phosphorus were elevated (208% and 128% of PRE, respectively p0.05), and ionized calcium reduced (88% of PRE, p0.05) after EXER. N-terminal propeptide of type 1 collagen, was elevated at POST (111% of PRE, p0.05), and the resorption marker, C-terminal propeptide of type 1 collagen, was elevated at 1 h (153% of PRE, p0.05). Osteocalcin was higher than PRE at 1 through 4 h post EXER (119-120% of PRE, p0.05). Sclerostin and Dickkopf-related protein-1 were elevated only at POST (132% and 121% of PRE, respectively, p0.05) during EXER. Trivial changes in biomarkers during successive recovery days were observed. These results suggest that 60 minutes of load carriage exercise elicits transient increases in bone formation and resorption that return to pre-exercise concentrations within 24 h post-exercise.

OBJECTIVES: Emerging evidence suggests that anti-inflammatory dietary patterns may improve depression, stress, and quality of life. Similar benefits are observed during weight loss interventions; however, the effect of combining these dietary patterns with weight loss is not clear. We evaluated the association between dietary inflammation and measures of psychological health in female military dependents with overweight and obesity during a behavioral weight loss intervention. METHODS: Participants (n = 120) received a 6-month intervention recommending dietary patterns with an anti-inflammatory profile. An energy-adjusted dietary inflammatory index (DII) score was calculated from 28 food components collected using 3 interviewer-administered multiple-pass 24-hour recalls at each study time point. A negative score indicates a lower-inflammatory dietary pattern, and a positive score indicates a pro-inflammatory pattern. Self-reported symptoms of depression, stress, general health, vitality, and psychological quality of life were measured by validated questionnaires. Multivariable linear mixed models were used to assess the association between 6-month changes in DII and each outcome and were adjusted for age, ethnicity, military rank of spouse, body weight, and physical activity. RESULTS: On average, females were 42.2 ± 11.8 years old with a body mass index of 34.9 ± 6.4 kg/m(2). The average DII score was 0.07 (range: −4.3, 3.0) at baseline. Six-month improvements in DII scores (i.e., for a 1-unit reduction) were associated with fewer self-reported symptoms of depression (β: −0.87; 95% confidence interval: −1.43, −0.31; P = 0.003) and stress (−0.85; −1.44, −0.26; P = 0.005), as well as higher general health (0.57; 0.23, 0.91; P = 0.001), vitality (0.45; 0.12, 0.77; P = 0.008), and psychological quality of life (0.33; 0.11, 0.55; P = 0.004). No significant associations between weight loss or physical activity and any outcome were observed in these models that included the DII. CONCLUSIONS: Anti-inflammatory dietary patterns are associated with beneficial effects on a range of psychological health and wellbeing measures independent of weight loss. FUNDING SOURCES: Jean Mayer USDA Human Nutrition Research Center on Aging Doctoral Scholarship; Department of Defense (DoD) grant W81XWH-14–2-0005 (SBR). Author views do not reflect official DoD or Army policy.

OBJECTIVES: Aerobic exercise (EX) reduces circulating ionized Ca (iCa) and increases parathyroid hormone (PTH), but the cause and consequences on Ca handling are unknown. The objective of this study was to determine the effects of EX on Ca kinetics using dual stable Ca isotopes. METHODS: Twenty-one healthy women (26.2 ± 6.7 yr; BMI: 22.8 ± 2.1 kg/m(2)) completed a randomized, crossover study consisting of two 6 day iterations separated by ≥2 wk. One iteration consisted of 3 d of load carriage EX 2 h after breakfast (1 hr treadmill walking at 65% VO(2max) wearing a vest weighing 30% body wt) on days 0, 2, 4, and the other a no-EX control (CON). Diet was controlled during each iteration, and matched to the volunteer's usual intake. On day 0, volunteers received one IV bolus of (42)Ca, and oral (44)Ca with each meal (0600,1200, and 1700). Serial blood draws and 3 urine pools (U1: 0600–1000, U2: 1000–2000, U3: 2000–0800) were collected on day 0; spot urines were collected on days 1–5. Ca isotope ratios were analyzed by Thermal Ionization Mass Spectrometry and total Ca by Siemens Dimension; fractional Ca absorption (FCA) was measured and kinetic modeling determined, rates of Ca deposition (VO+) and resorption (VO–) from bone, and bone Ca balance (Vbal). Circulating PTH and iCa were also measured before, during and after exercise. Data were analyzed by paired T-test or linear mixed models using SPSS. RESULTS: On day 0, PTH increased 45 min into EX as compared to pre (+36 pg/ml, P 0.05). FCA was greater during EX (26.6 ± 8.1%) compared to CON (23.9 ± 8.3%, P 0.05). CONCLUSIONS: During EX, an increase in FCA and decrease in UCa resulted in a positive shift in Ca balance. The rapid reduction in circulating iCa may be due to a change in the miscible Ca pool, resulting in increased PTH and changes in intestinal and renal Ca handling that support a more positive Ca balance. FUNDING SOURCES: Defense Health Program.

Stress fractures are common overuse injuries caused by repetitive bone loading. These fractures are of particular concern for military recruits and athletes resulting in attrition in up to 60% of recruits that sustain a fracture. Army and Navy recruits supplemented with daily calcium and vitamin D (Ca + D) demonstrated improved bone strength and reduced stress fractures. The aim of the current study was to evaluate whether Ca + D supplementation improves measures of bone health in recruits undergoing United States Marine Corps initial military training (IMT), and whether the effect of supplementation on indices of bone health varied by season. One-hundred ninety-seven Marine recruits (n = 107 males, n = 90 females, mean age = 18.9 ± 1.6 y) were randomized to receive either Ca + D fortified snack bars (2000 mg Ca and 1000 IU vitamin D per day) or placebo divided into twice daily doses during 12 weeks of IMT. Anthropometrics, fasted blood samples, and peripheral quantitative computed tomography (pQCT) scans of the tibial metaphysis and diaphysis were collected upon entrance to- and post-training (12 weeks later). Half of the volunteers entered training in July and the other half started in February. Time-by-group interactions were observed for vitamin D status (25OHD) and the bone turnover markers, BAP, TRAP and OCN. 25OHD increased and BAP, TRAP and OCN all decreased in the Ca + D group (p .05). Training increased distal tibia volumetric BMD (+1.9 ± 2.8%), BMC (+2.0 ± 3.1%), and bone strength index (BSI; +4.0 ± 4.0%) and diaphyseal BMC (+1.0 ± 2.2%) and polar stress strain index (SSIp; +0.7 ± 2.1%) independent of Ca + D supplementation (p .05 for all). When analyzed by season, change in BSI was greater in the Ca + D group as compared to placebo in the summer iteration only (T*G; p .05). No other effects of supplementation on bone tissue were observed. When categorized by tertile of percent change in BSI, recruits demonstrating the greatest changes in BSI and 25OHD entered training with the lowest levels of 25OHD (p .05). Over all, these results suggest that Ca + D supplementation reduced some markers of bone formation and resorption and the decline in 25OHD over training in volunteers that started training in the summer was prevented by supplementation. Baseline 25OHD and trajectory may impact bone responses to IMT, but little effect of Ca + D supplementation was observed at the investigated doses.

Background Stress fracture risk is elevated during initial military training (IMT), particularly in lower-extremity bones such as the tibia. Although the etiology of stress fractures is multifactorial, lower bone strength increases risk. Objective The objective of this study was to assess, through the use of peripheral quantitative computed tomography, whether adherence to a dietary pattern rich in calcium, potassium, and protein before IMT is positively associated with bone indexes in young adults entering IMT. Design A cross-sectional analysis was performed with the use of baseline data from 3 randomized controlled trials in Army, Air Force, and Marine recruits (n = 401; 179 men, 222 women). Dietary intake was estimated from a food-frequency questionnaire. A dietary pattern characterized by calcium, potassium, and protein was derived via reduced rank regression and a pattern z score was computed for each volunteer, where higher scores indicated greater adherence to the pattern. At the 4% (metaphysis) and 14% (diaphysis) sites of the tibia, bone mineral content (BMC), volumetric bone mineral density, robustness, and strength indexes were evaluated. Associations between dietary pattern z score as the predictor variable and bone indexes as the response variables were evaluated by multiple linear regression. Results Pattern z score was positively associated with BMC (P = 0.004) and strength (P = 0.01) at the metaphysis and with BMC (P = 0.0002), strength (P = 0.0006), and robustness (P = 0.02) at the diaphysis when controlling for age, sex, race, energy, smoking, education, and exercise. Further adjustment for BMI attenuated the associations, except with diaphyseal BMC (P = 0.005) and strength (P = 0.01). When height and weight were used in place of body mass index, the association with BMC remained (P = 0.046). Conclusions A dietary pattern rich in calcium, potassium, and protein is positively associated with measures of tibia BMC and strength in recruits entering IMT. Whether adherence to this dietary pattern before IMT affects injury susceptibility during training remains to be determined. These trials were registered at clinicaltrials.gov as NCT01617109 and NCT02636348.

BACKGROUND Vitamin D deficiency (VDD), defined as serum 25-hydroxyvitamin D (25[OH]D) levels < 20 ng/mL [to convert 25[OH]D ng/mL to nmol/L, multiply by 2.5]) is prevalent in young adults and has been associated with adverse health outcomes, including stress fracture during periods of increased physical activity such as military training. Foods commonly consumed at breakfast provide an important source of vitamin D, yet breakfast skipping is common among young adults. However, whether breakfast skipping is associated with VDD in young adults is unclear. OBJECTIVES This study aimed to determine whether breakfast skipping is associated with odds of VDD among recruits entering initial military training (IMT), and with changes in serum 25(OH)D during IMT. In addition, whether diet quality and vitamin D intake mediated these associations was determined. DESIGN Secondary analysis of individual participant data collected during five IMT studies. Breakfast skipping (≥ 3 times/week) was self-reported. Dietary intake was determined using food frequency questionnaires, and vitamin D status was assessed using circulating 25(OH)D concentrations pre- and post-IMT. PARTICIPANTS AND SETTING Participants were healthy US Army, US Air Force, and US Marine recruits (N = 1,569, 55% male, mean ± standard deviation age 21 ± 4 years) entering military service between 2010 and 2015 at Fort Jackson, SC; Fort Sill, OK; Lakeland Air Force Base, TX; or the Marine Corps Recruit Depot, Parris Island, SC. MAIN OUTCOME MEASURES Primary outcomes were VDD pre-IMT and change in 25(OH)D from pre- to post-IMT. STATISTICAL ANALYSIS PERFORMED Associations were determined using multivariate-adjusted logistic and linear regression and mediation models. RESULTS Forty-six percent of military recruits were classified as breakfast skippers pre-IMT, and 30% were VDD. Breakfast skipping was associated with a higher odds of pre-IMT VDD (odds ratio 1.5, 95% CI 1.1 to 1.9), and lower vitamin D intake and diet quality were partial mediators of the association. Serum 25(OH)D concentrations improved (P = 0.01) among habitual breakfast skippers versus nonskippers during IMT; however, regression to the mean could not be ruled out. Neither change in diet quality nor vitamin D intake were associated with change in 25(OH)D concentrations during IMT. CONCLUSIONS Breakfast skipping is prevalent among incoming military recruits and is associated with VDD. This relationship may be mediated by lower diet quality and vitamin D intake.

BACKGROUND Lifestyle interventions are the first-line treatment for obesity, but participant weight loss is typically low. OBJECTIVES We evaluated the efficacy of an alternative lifestyle intervention [Healthy Weight for Living (HWL)] compared with a modified Diabetes Prevention Program (m-DPP). HWL was based on a revised health behavior change model emphasizing hunger management and the development of healthy food preferences. m-DPP was a standard Diabetes Prevention Program implemented with counselor time matched to HWL. Participants were adult dependents of military personnel and had overweight or obesity. METHODS Participants were randomly assigned to HWL (n = 121) or m-DPP (n = 117), delivered primarily by group videoconference with additional midweek emails. The primary outcome was 12-mo weight change. Secondary outcomes included 6-mo changes in cardiometabolic risk factors and diet. Intention-to-treat (ITT) and complete case (CC) analyses were performed using linear mixed models. RESULTS Retention did not differ between groups (72% and 66% for HWL and m-DPP at 12 mo, respectively; P = 0.30). Mean ± SE adjusted 12-mo weight loss in the ITT cohort was 7.46 ± 0.85 kg for HWL and 7.32 ± 0.87 kg for m-DPP (P = 0.91); in the CC cohort, it was 7.83 ± 0.82 kg for HWL and 6.86 ± 0.88 kg for m-DPP (P = 0.43). Thirty-eight percent of HWL and 30% of m-DPP completers achieved ≥10% weight loss (P = 0.32). Improvements in systolic blood pressure, LDL cholesterol, triglycerides, fasting glucose, general health, sleep, and mood were similar across groups; improvements in diastolic blood pressure were greater in m-DPP. Adjusted group mean reductions in energy intake were not significantly different between groups, but HWL participants were more adherent to their dietary prescription for lower glycemic index and high fiber and protein (P = 0.05 to

OBJECTIVES: Female military recruits are at risk for developing stress fractures during initial military training (IMT). Accurate assessment of both calcium (Ca) and vitamin D (vit D) intake may support the development of targeted dietary interventions for those at risk of deficiency. The objective of this study was to investigate the relationships between different dietary assessment methods for estimated dietary Ca and vit D intakes in a healthy population. METHODS: Active, healthy females (18–42 yr, 19–26 kg/m(2) body mass index) recruited for an exercise study were included. Study dietitians administered: three 24-hour recalls (24HR) (baseline and before two exercise interventions), full-length Block 2014 Food Frequency Questionnaire (FFQ) (baseline), and Block Calcium and Vitamin D Screener (baseline). Twenty-four HR data were averaged and then quantified by Food Processor SQL. Block questionnaires were analyzed by NutritionQuest. Ca and vit D intakes were energy adjusted using the density method for all assessment methods except the screener. Means, standard deviations (SD), and correlations between 24HR variables were analyzed using SPSS. RESULTS: Twenty-one participants completed the study: (mean ± SD) 26.2 ± 6.7 yr, 22.76 ± 2.12 kg/m(2). Estimated intakes from the 24HR, FFQ, and screener for Ca (mg/d) were 741 ± 403,1001 ± 420, and 446 ± 270, respectively and for vit D (μg/d) were 2.8 ± 3, 4.6 ± 2.6, and 1.8 ± 1.6, respectively. Moderate, positive correlations were found between the 24HR and unadjusted FFQ Ca intake (r = 0.636, P = 0.002), and the 24HR and adjusted FFQ vit D intake (r = 0.561, P = 0.008). No significant correlations were observed between the nutrients of interest as measured by the 24HR and screener. CONCLUSIONS: Intake estimates of Ca and vit D from the full-length FFQ displayed moderate agreement with those estimated by the 24HR, and the FFQ produced relatively higher estimates. Given this, the FFQ may be more practical for use in an IMT setting, for estimating relative Ca and vit D intakes, than the 24HR to identify individuals who may benefit from interventions promoting bone health. FUNDING SOURCES: Defense Health Program. The views expressed in this abstract are those of the authors and do not reflect the official policy of the Department of Army, Department of Defense, or the U.S. Government.

Background The 2010 Healthy Eating Index (HEI-2010), a measure of diet quality, is used to quantify adherence to the Dietary Guidelines for Americans. Better HEI scores have been associated with positive health outcomes; however, the relationship between diet quality and psychological resilience, a mental health attribute for coping with adversity, has not been assessed. Objective The objective of the present study was to assess the relationship between diet quality and psychological resilience, and the relationship between resilience and demographics, anthropometrics, socioeconomic status, and health behavior. Design In this cross-sectional study, HEI-2010 scores and resilience were assessed using the Block food frequency questionnaire and the Connor-Davidson Resilience Scale. Other factors that can affect the relationship between HEI-2010 scores and resilience were assessed using surveys, and height and weight were measured to calculate body mass index. Participants/setting Male and female Army and Air Force recruits (n=834) enrolled in a randomized controlled trial and 656 (mean±standard deviation [SD] age=21±3.3 years) were included in this analysis. Data were collected before the initiation of military training at Fort Sill, OK (2012-2013) and Lackland Air Force Base, TX (2013-2014). Statistical analysis performed Participants were split into low- and high-resilience groups based on Connor-Davidson Resilience Scale scores. Student's t test and χ 2 tests were used to determine differences between groups for continuous and categorical variables, respectively. Logistic regression was utilized to identify predictors of resilience. Results Better diet quality was associated with resilience; higher HEI predicted an increased likelihood (odds ratio=1.02; 95% CI 1.01 to 1.04) of a participant being in the high-resilience group after including race, ethnicity, education, smoking, age, body mass index, sex, and military branch in the full model. The data indicate that with every 10-point increase in HEI score, there was a 22% increased likelihood of being in the high-resilience group. Conclusions Registered dietitian nutritionists should continue to encourage attainable changes to improve diet; study data suggest that small improvements in diet quality can be associated with better psychological resilience.

OBJECTIVES: The Dietary Guidelines for Americans 2015–2020 indicate that potassium, choline, magnesium, calcium, vitamins A, D, E, and C are underconsumed (i.e., shortfall) micronutrients. Intakes of specific performance-related micronutrients (i.e., calcium, magnesium, folate, choline, iron, zinc, and vitamins A, D, E, B1, B2, B3, and B12), may also be a concern, as suboptimal intakes may limit adaptations to unaccustomed physical training, such as initial military training (IMT). Protein-containing foods are nutrient-dense; therefore, dietary protein intake may alter the amount of shortfall and performance-related micronutrients habitually consumed. This study explored associations between dietary protein (PRO) intake and shortfall or performance-related micronutrient intakes at IMT accession. METHODS: A 3-month food frequency questionnaire was used to estimate habitual dietary intake in male (n = 276, age: Mean (SD), 21.1 (3.8)) and female (n = 254, age: 21.2 (3.7)) recruits. Multivariate-adjusted MANCOVA and ANCOVA models were used to identify associations between quartiles of PRO intake and shortfall micronutrients or performance-related micronutrients. Models were adjusted for age, sex, ethnicity, race, physical activity, energy density, and total energy intake. RESULTS: Mean (SE) energy-adjusted PRO intakes were 29.3 (3.2), 36.0 (1.4), 40.8 (1.3), and 47.7 (3.9) g/1000 kcal for quartiles 1–4, respectively. Composite shortfall micronutrient intake differed (P

Eating behaviors such as eating fast and ignoring internal satiety cues are associated with overweight/obesity, and may be influenced by environmental factors. This study examined changes in those behaviors, and associations between those behaviors and BMI, cardiometabolic biomarkers, and diet quality in military recruits before and during initial military training (IMT), an environment wherein access to food is restricted. Eating rate and reliance on internal satiety cues were self-reported, and BMI, body fat, cardiometabolic biomarkers, and diet quality were measured in 1389 Army, Air Force and Marine recruits (45% female, mean ± SEM BMI = 24.1 ± 0.1 kg/m2) before and after IMT. Pre-IMT, habitually eating fast relative to slowly was associated with a 1.1 ± 0.3 kg/m2 higher BMI (P

Food frequency questionnaires (FFQs) estimate habitual dietary intake and require evaluation in populations of interest in order to determine accuracy. Thus, the purpose of this study was to determine agreement between circulating biomarkers and FFQ estimated dietary intake in a military population consuming all meals in a dining facility over 12 weeks.2014 Block FFQs were administered and fasted blood samples were drawn to assess nutritional biomarkers at the end of a 12-week training period in male (n = 141) and female (n = 125) Marine recruits undergoing initial military training. FFQ estimates of alpha- and beta-carotene, folate, and fruit and vegetable intake and circulating concentrations of serum alpha- and beta-carotene and serum and erythrocyte folate were measured. Partial correlations were used in the full model, and weighted kappa coefficients were used to determine agreement between ranking quartiles of dietary intake estimates with corresponding biomarker status quartiles.Serum and dietary intake of alpha-carotene were positively associated in males (p = 0.009) and females (p 0.001), as was serum and intake of beta-carotene (males, p = 0.002; females, p 0.001). Alpha-carotene was positively associated with vegetable intake in males (p = 0.02) and beta-carotene with vegetable intake in females (p = 0.003). Serum folate in males (p = 0.002) and erythrocyte folate in females (p = 0.02) were associated with dietary folate intake. In females, the relationships between biomarker and dietary estimates yielded significant kappa coefficients. In males, a significant kappa coefficient was observed for erythrocyte folate and dietary intake of folate only. The kappa coefficient for serum and estimated intake of beta-carotene was not significant in males.Twelve-week habitual intake of alpha-and beta-carotene and folate were correlated with circulating biomarkers in a military training population. The 2014 Block FFQ was able to accurately rank females into quartiles of nutrient status based on intake, while males were ranked less accurately than females.

Initial military training (IMT) is associated with increased stress fracture risk. In prior studies, supplemental calcium (Ca) and vitamin D provided daily throughout IMT reduced stress fracture incidence, suppressed PTH, and improved measures of bone health compared to placebo. Data were analyzed from a randomized, double-blind, placebo-controlled trial to determine whether SNPs in Ca and vitamin D related genes were associated with circulating biomarkers of bone metabolism in young adults entering IMT, and whether responses to Ca and vitamin D supplementation were modulated by genotype. Associations between SNPs including: vitamin D receptor (VDR), vitamin D binding protein (DBP), and 1-alpha-hydroxylase (CYP27B1), and circulating biomarkers were measured in fasting blood samples from volunteers (n = 748) starting IMT. Volunteers were block randomized by race and sex to receive Ca (2000 mg) and vitamin D (1000 IU) or placebo daily throughout Army or Air Force IMT (7-9 wk). Total Ca and vitamin D intakes were calculated as the sum of supplemental intake based on intervention compliance and dietary intake. Relationships between SNPs, Ca and vitamin D intake tertile, and change in biomarkers were evaluated in trial completers (n = 391). At baseline, the minor allele of a DBP SNP (rs7041) was positively associated with both 25OHD (B = 4.46, p = 1.97E-10) and 1,25(OH)2D3 (B = 9.63, p =

Ca/vitamin D supplementation maintains bone health and decreases stress fracture risk during initial military training (IMT); however, there is evidence that Ca may negatively affect the absorption of other critical micronutrients, particularly Fe. The objective of this randomised, double-blind, placebo-controlled trial was to determine whether providing 2000 mg/d Ca and 25µg/d vitamin D in a fortified food product during 9 weeks of military training affects Fe status in young adults. Male (n98) and female (n54) volunteers enrolled in US Army basic combat training (BCT) were randomised to receive a snack bar with Ca/vitamin D (n75) or placebo (snack bar without Ca/vitamin D;n77) and were instructed to consume 2 snack bars/d between meals throughout the training course. Circulating ionised Ca was higher (PPPP>0·05) in markers of Fe status between placebo and Ca/vitamin D groups. Collectively, these data indicate that Ca/vitamin D supplementation through the use of a fortified food product consumed between meals does not affect Fe status during IMT.

OBJECTIVES: Vitamin D deficiency (VDD) and iron deficiency (ID) are associated with injury risk and performance, respectively, in military recruits during initial military training (IMT). Breakfast skipping is prevalent among young adults and contributes to decreased intakes of vitamin D and iron. However, whether breakfast skipping is associated with VDD and ID in military recruits, and whether the mandatory breakfast attendance required in IMT mitigates VDD and ID is unknown. METHODS: Army, Air Force, and Marine recruits (N = 2117, 42% male, mean ± SD age 21 ± 4y) completed a food frequency questionnaire pre-IMT, and provided blood samples pre- and post-IMT. Breakfast skipping was self-reported and defined as skipping breakfast ≥3 d/wk pre-IMT. Diet quality was determined by Healthy Eating Index. ID was defined as meeting ≥2 of the following: serum ferritin 15%. VDD was defined as serum 25-hydroxyvitamin D (25OHD)

Introduction The military dietary reference intakes (MDRIs), outlined in Army Regulation 40-25, OPNAVINST 10110.1/MCO10110.49, AFI 44-141, establish standards intended to meet the nutrient requirements of Warfighters. Therefore, the purpose of this study was to comprehensively compare the revised MDRIs, published in 2017, with estimated dietary intakes in U.S. military personnel. Materials and methods During this cross-sectional study, Block food frequency questionnaires were administered at the end of the 9-week basic combat training course to estimate dietary intake during basic combat training in male (n = 307) and female (n = 280) recruits. The cut-point method was used to determine nutrient adequacy in comparison to the MDRIs. This study was approved by the Institutional Review Board of the U.S. Army Research Institute of Environmental Medicine. Results Recruits consumed an adequate amount of vitamins A, C and K, as well as the B-vitamins, and phosphorus, selenium, zinc, and protein and carbohydrate as a percentage of total calories when compared with MDRI standards. Vitamin D was the short-fall nutrient affecting the greatest number of participants, as 55 and 70% of males and females, respectively, consumed less than 33% of the MDRI. In addition, less than 50% of males met the MDRI for linoleic and α-linolenic acid, fiber, vitamin E, magnesium, and potassium, and less than 50% of females met the MDRI for α-linolenic acid, fiber, vitamin E, calcium, iron, magnesium, and potassium. In contrast, fat and sodium were over-consumed by both males (78 and 87%, respectively) and females (73 and 72%, respectively). Conclusion The main findings of this study were that vitamins D and E, magnesium, potassium, α-linolenic acid, and fiber were under consumed by male and female recruits while males also did not consume adequate linoleic acid and females did not consume adequate calcium and iron. Future prospective research studies are needed to determine possible health and performance impacts that may be associated with suboptimal intake of these nutrients.

Submariners spend prolonged periods submerged without sunlight exposure and may benefit from vitamin D supplementation to maintain vitamin D status. The primary objective of this study was to determine the efficacy of daily vitamin D supplementation on maintenance of 25-hydroxyvitamin D (25(OH)D) during a 3-month submarine patrol. Submariners were randomly divided into three groups: placebo (n = 16), 1,000 IU/day (n = 20), or 2,000 IU/day (n = 17). Anthropometrics, self-reported dietary calcium and vitamin D intake, serum markers of vitamin D and bone metabolism, and peripheral quantitative computed tomography (pQCT) parameters of the tibia were determined before and after the patrol. Prior to departure, 49 % of the subjects were vitamin D insufficient (

Initial military training (IMT) is associated with increased stress fracture risk. In prior studies, supplemental calcium (Ca) and vitamin D provided daily throughout IMT reduced stress fracture incidence, suppressed parathyroid hormone (PTH), and improved measures of bone health compared with placebo. Data were analyzed from a randomized, double-blind, placebo-controlled trial to determine whether single-nucleotide polymorphisms (SNPs) in Ca and vitamin D-related genes were associated with circulating biomarkers of bone metabolism in young adults entering IMT, and whether responses to Ca and vitamin D supplementation were modulated by genotype. Associations between SNPs, including vitamin D receptor (VDR), vitamin D binding protein (DBP), and 1-alpha-hydroxylase (CYP27B1), and circulating biomarkers were measured in fasting blood samples from volunteers (n = 748) starting IMT. Volunteers were block randomized by race and sex to receive Ca (2000 mg) and vitamin D (1000 IU) or placebo daily throughout Army or Air Force IMT (7 to 9 weeks). Total Ca and vitamin D intakes were calculated as the sum of supplemental intake based on intervention compliance and dietary intake. Relationships between SNPs, Ca, and vitamin D intake tertile and change in biomarkers were evaluated in trial completers (n = 391). At baseline, the minor allele of a DBP SNP (rs7041) was positively associated with both 25OHD (B = 4.46, p = 1.97E-10) and 1,25(OH)

Confined space, limited exercise equipment, rotating shift work and reduced sleep may affect cardiometabolic health in submariners. To test this hypothesis, 53 male U.S. Submariners (20–39 years) were studied before and after a 3-month routine submarine patrol. Measures included anthropometrics, dietary and physical activity, biomarkers of cardiometabolic health, energy and appetite regulation, and inflammation. Before deployment, 62% of submariners had a body fat % (BF%) ≥ 25% (obesity), and of this group, 30% met the criteria for metabolic syndrome. In obese volunteers, insulin, the homeostatic model assessment of insulin resistance (HOMA-IR), leptin, the leptin/adiponectin ratio, and pro-inflammatory chemokines growth-related oncogene and macrophage-derived chemokine were significantly higher compared to non-obese submariners. Following the patrol, a significant mean reduction in body mass (5%) and fat-mass (11%) occurred in the obese group as a result of reduced energy intake (~2000 kJ) during the patrol; and, independent of group, modest improvements in serum lipids and a mean reduction in interferon γ-induced protein 10 and monocyte chemotactic protein 1 were observed. Since 43% of the submariners remained obese, and 18% continued to meet the criteria for metabolic syndrome following the patrol, the magnitude of weight loss was insufficient to completely abolish metabolic dysfunction. Submergence up to 3-months, however, does not appear to be the cause of obesity, which is similar to that of the general population.

Iron is an essential micronutrient known to affect physical and cognitive performance. Studies indicate a significant reduction in iron status in female Soldiers immediately following military training, although the comparative effects of military training on iron status between male and female Soldiers have not been examined. The objective of this study was to compare the longitudinal effects of US Army basic combat training (BCT) on iron status indicators in a group of male and female Soldiers.A total of 154 male and female Soldiers (89 and 65, respectively) completed the study. Blood was collected at 4 time-points during BCT (weeks 0, 3, 6, 9) and dietary iron intake was assessed at weeks 0 and 9. Iron status indicators included hemoglobin, serum ferritin (SF), soluble transferrin receptor (sTfR), and transferrin saturation (TS).Iron status was greater in male Soldiers than female Soldiers, as hemoglobin and SF levels were higher (P.05) and sTfR levels were lower (P.05) in males as compared to females at each time-point. Despite a mean increase of greater than 25% in iron intake (mg/day) among both male (15±13 to 20.2±14.4) and female Soldiers (12.8±9.7 to 16±6.2) over the course of BCT, iron status declined in both groups. As compared to baseline, SF declined (P.05) by 21% and 47%, sTfR increased (P.05) by 17% and 30%, and TS declined (P.05) by 23% and 54% in male and female Soldiers, respectively, over the course of BCT.These data indicate that although dietary iron intake improves, iron status declines in both male and female Soldiers during BCT, and the decline in female Soldiers is of a greater magnitude. Future studies should aim to determine the mechanism by which iron status declines during military training, with a focus on functional outcomes affecting Soldier health and performance.

Initial military training (IMT) is associated with elevated bone turnover and an increased risk for stress fractures. Supplemental Ca and vitamin D during IMT improves bone health, although previous studies indicate that supplemental Ca intake may interfere with iron absorption, affecting iron status. The objective of this study was to determine the effect of daily Ca and vitamin D supplementation (2000 mg and 1000 IU/day, respectively) on biochemical indicators of iron status during IMT. Biomarkers (hemoglobin, Hgb; serum ferritin, SF; soluble transferrin receptor, sTfR; transferrin saturation TS) were assessed in fasted volunteers (n = 152, males = 98, females = 54; age [mean ± SD] = 21 ± 4 yrs) at the start and end of a 9-wk IMT course. Supplemental Ca and vitamin D were provided in a fortified snack food, which was consumed between meals 2x/day throughout IMT. Iron status declined over the course, as Hgb, SF and TS declined (8, 50, and 37%, respectively; P < 0.05; main effect of time) and sTfR increas...

Stress fracture incidence is high during initial military training (IMT) with 2-6% of male and 8-21% of female recruits sustaining fractures. Identification and mitigation of risk factors is critic...

Calcium and vitamin D are essential nutrients for bone health. Periods of activity with repetitive mechanical loading, such as military training, may result in increases in parathyroid hormone (PTH), a key regulator of Ca metabolism, and may be linked to the development of stress fractures. Previous studies indicate that consumption of a Ca and vitamin D supplement may reduce stress fracture risk in female military personnel during initial military training, but circulating markers of Ca and bone metabolism and measures of bone density and strength have not been determined. This randomized, double-blind, placebo-controlled trial sought to determine the effects of providing supplemental Ca and vitamin D (Ca+Vit D, 2000mg and 1000IU/d, respectively), delivered as 2 snack bars per day throughout 9weeks of Army initial military training (or basic combat training, BCT) on PTH, vitamin D status, and measures of bone density and strength in personnel undergoing BCT, as well as independent effects of BCT on bone parameters. A total of 156 men and 87 women enrolled in Army BCT (Fort Sill, OK; 34.7°N latitude) volunteered for this study. Anthropometric, biochemical, and dietary intake data were collected pre- and post-BCT. In addition, peripheral quantitative computed tomography was utilized to assess tibia bone density and strength in a subset of volunteers (n=46). Consumption of supplemental Ca+Vit D increased circulating ionized Ca (group-by-time, P=0.022), maintained PTH (group-by-time, P=0.032), and increased the osteoprotegerin:RANKL ratio (group-by-time, P=0.006). Consistent with the biochemical markers, Ca+Vit D improved vBMD (group-by-time, P=0.024) at the 4% site and cortical BMC (group-by-time, P=0.028) and thickness (group-by-time, P=0.013) at the 14% site compared to placebo. These data demonstrate the benefit of supplemental Ca and vitamin D for maintaining bone health during periods of elevated bone turnover, such as initial military training. This trial was registered with ClincialTrials.gov, NCT01617109.

Poor vitamin D status is linked to musculoskeletal injuries, such as stress fracture, during military training. The objective of this trial was to determine the effect of daily calcium (Ca) and vit...

The objectives of this study were to use the healthy eating index (HEI) as a tool to characterize diet quality in Soldiers (n=135) during basic combat training (BCT), and to assess the effects of BCT on diet quality by comparing HEI scores before and after the training period.HEI scores were calculated from a 110-item semiquantitative food frequency questionnaire. Soldiers were then divided into tertiles (high, medium, and low) of diet quality based upon HEI scores at the start of BCT.No relationships between pre-BCT total HEI score and age, sex, racial background, or physical activity were observed. The odds of being a smoker were 4.75 times higher for those in the low HEI tertile and 3.03 times higher for those in the medium HEI tertile when compared to those in the high HEI tertile (95% CI, 1.67, 13.48 and 1.04, 8.82 respectively). Diet quality improved in the medium and low HEI tertiles over the course of BCT, as total HEI scores increased by 22% and 46% respectively (P.05) with time in these groups. Although different at the start of BCT, HEI scores were similar between the medium and high HEI tertiles at the end of BCT.Study findings suggest that the BCT dining environment elicits positive changes in diet quality for Soldiers who enter military training with lower diet quality, and the HEI appears to be a useful tool to identify military personnel with lower diet quality at the start of training. This may provide the opportunity to target interventions such as diet counseling and education in an effort to improve Soldier health and performance.

Background Vitamin D is an essential nutrient for maintaining bone health, to include protecting against stress fracture during periods of rapid bone turnover. The objective of this longitudinal, observational study was to assess vitamin D status, biomarkers of bone turnover, and vitamin D and calcium intake in female Soldiers (n = 91) during US Army basic combat training (BCT). Methods Anthropometric, biological and dietary intake data were collected at wk 0, 3, 6, and 9 of the 10 wk BCT course. Mixed models repeated measures ANOVAs were used to assess main effects of time, race, and time-by-race interactions. Results White volunteers experienced a decrease in serum 25(OH)D levels, whereas non-white volunteers experienced an increase during BCT. However, serum 25(OH)D levels were lower in non-whites than whites at all timepoints (P-interaction Conclusions These findings demonstrate that female Soldiers experience dynamic changes in vitamin D status coupled with increased bone turnover and potentially inadequate vitamin D and calcium intake during military training.

Background Cardiometabolic disease risk in US military recruits and the effects of military training have not been determined. This study examined lifestyle factors and biomarkers associated with cardiometabolic risk in US Army recruits (209; 118 male, 91 female, 23±5 yr) before, during, and after basic combat training (BCT). Methodology/Principal Findings Anthropometrics; fasting total (TC), high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol; triglycerides (TG); glucose; and insulin were measured at baseline and every 3 wks during the 10 wk BCT course. At baseline, 14% of recruits were obese (BMI>30 kg/m2), 27% were cigarette smokers, 37% were sedentary, and 34% reported a family history of cardiometabolic disease. TC was above recommended levels in 8%, LDL in 39%, TG in 5%, and glucose in 8% of recruits, and HDL was below recommended levels in 33% of recruits at baseline. By week 9, TC decreased 8%, LDL 10%, TG 13%, glucose 6% and homeostasis model assessment of insulin resistance (HOMA-IR) 40% in men (P