Process evaluation results from the HEALTHY nutrition intervention to modify the total school food environment.

The process evaluation of HEALTHY, a large multi-center trial to decrease type 2 diabetes mellitus in middle school children, monitored the implementation of the intervention to ascertain the extent that components were delivered and received as intended. The purpose of this article is to report the process evaluation findings concerning the extent to which the HEALTHY nutrition intervention was implemented during the HEALTHY trial. Overall, the observed fidelity of implementing nutrition strategies improved from baseline to the end of the study. By the last semester, all but two nutrition process evaluation goals were met. The most challenging goal to implement was serving high fiber foods, including grain-based foods and legumes. The easiest goals to implement were lowering the fat content of foods offered and offering healthier beverages. The most challenging barriers experienced by research dietitians and food service staff were costs, availability of foods and student acceptance. Forming strong relationships between the research dietitians and food service staff was identified as a key strategy to meet HEALTHY nutrition goals.

Can vitamin D deficiency cause diabetes and cardiovascular diseases? Present evidence and future perspectives.

Several studies have shown that vitamin D may play a role in many biochemical mechanisms in addition to bone and calcium metabolism. Recently, vitamin D has sparked widespread interest because of its involvement in the homeostasis of the cardiovascular system. Hypovitaminosis D has been associated with obesity, related to trapping in adipose tissue due to its lipophilic structure. In addition, vitamin D deficiency is associated with increased risk of cardiovascular disease (CVD) and this may be due to the relationship between low vitamin D levels and obesity, diabetes mellitus, dyslipidaemia, endothelial dysfunction and hypertension. However, although vitamin D has been identified as a potentially important marker of CVD, the mechanisms through which it might modulate cardiovascular risk are not fully understood. Given this background, in this work we summarise clinical retrospective and prospective observational studies linking vitamin D levels with cardio-metabolic risk factors and vascular outcome. Moreover, we review various randomised controlled trials (RCTs) investigating the effects of vitamin D supplementation on surrogate markers of cardiovascular risk. Considering the high prevalence of hypovitaminosis D among patients with high cardiovascular risk, vitamin D replacement therapy in this population may be warranted; however, further RCTs are urgently needed to establish when to begin vitamin D therapy, as well as to determine the dose and route and duration of administration.

Long-term effect of exercise on bone mineral density and body composition in post-menopausal ex-elite athletes: a retrospective study.

OBJECTIVES: The aim of this retrospective study was to determine the long-term effect of exercise on bone mineral density (BMD), bone mineral content (BMC) and body composition (BC) in post-menopausal women who were elite athletes during their youth compared with sedentary controls. SUBJECTS/METHODS: It is a retrospective study and carried out in an outpatient clinic. A total of 48 post-menopausal women (54-73 years of age) were enrolled. Ex-elite athletes with long-term (>20 years) histories of significant training and performance were divided into two groups: weight-bearing sports (runners, n=12) and non-weight-bearing sports (swimmers, n=12). The athletes were age matched with sedentary controls (n=24). BMD, BMC and BC were measured using dual-energy X-ray absorptiometry. Healthcare and sport activity histories were evaluated using a questionnaire. RESULTS: No significant differences were found with regard to body weight, height, body mass index and hours of activity between the two groups of athletes. There were no significant differences in activity levels between athletes and controls at the time of this study. BMD and BMC were not significantly different between athletes; they were significantly higher in athletes than in controls (P<0.001). Although the ex-athletes did not significantly differ in BC, left and right lean arm mass and arm BMD were significantly higher in swimmers than in runners (P<0.0001). CONCLUSIONS: The high level of physical activity observed in female athletes is associated with improved muscle mass, BMD and BMC, and physical activity during youth seems to have a beneficial effect on bone mass and helps to prevent bone loss due to aging.

Rationale, design and methods of the HEALTHY study nutrition intervention component.

The HEALTHY study was a randomized, controlled, multicenter and middle school-based, multifaceted intervention designed to reduce risk factors for the development of type 2 diabetes. The study randomized 42 middle schools to intervention or control, and followed students from the sixth to the eighth grades. Here we describe the design of the HEALTHY nutrition intervention component that was developed to modify the total school food environment, defined to include the following: federal breakfast, lunch, after school snack and supper programs; a la carte venues, including snack bars and school stores; vending machines; fundraisers; and classroom parties and celebrations. Study staff implemented the intervention using core and toolbox strategies to achieve and maintain the following five intervention goals: (1) lower the average fat content of foods, (2) increase the availability and variety of fruits and vegetables, (3) limit the portion sizes and energy content of dessert and snack foods, (4) eliminate whole and 2% milk and all added sugar beverages, with the exception of low fat or nonfat flavored milk, and limit 100% fruit juice to breakfast in small portions and (5) increase the availability of higher fiber grain-based foods and legumes. Other nutrition intervention component elements were taste tests, cafeteria enhancements, cafeteria line messages and other messages about healthy eating, cafeteria learning laboratory (CLL) activities, twice-yearly training of food service staff, weekly meetings with food service managers, incentives for food service departments, and twice yearly local meetings and three national summits with district food service directors. Strengths of the intervention design were the integration of nutrition with the other HEALTHY intervention components (physical education, behavior change and communications), and the collaboration and rapport between the nutrition intervention study staff members and food service personnel at both school and district levels.

Rationale, design and methods of the HEALTHY study physical education intervention component.

The HEALTHY primary prevention trial was designed to reduce risk factors for type 2 diabetes in middle school students. Middle schools at seven centers across the United States participated in the 3-year study. Half of them were randomized to receive a multi-component intervention. The intervention integrated nutrition, physical education (PE) and behavior changes with a communications strategy of promotional and educational materials and activities. The PE intervention component was developed over a series of pilot studies to maximize student participation and the time (in minutes) spent in moderate-to-vigorous physical activity (MVPA), while meeting state-mandated PE guidelines. The goal of the PE intervention component was to achieve > or =150 min of MVPA in PE classes every 10 school days with the expectation that it would provide a direct effect on adiposity and insulin resistance, subsequently reducing the risk of type 2 diabetes in youth. The PE intervention component curriculum used standard lesson plans to provide a comprehensive approach to middle school PE. Equipment and PE teacher assistants were provided for each school. An expert in PE at each center trained the PE teachers and assistants, monitored delivery of the intervention and provided ongoing feedback and guidance.

Rationale, design and methods for process evaluation in the HEALTHY study.

The HEALTHY study was a multi-site randomized trial designed to determine whether a 3-year school-based intervention targeting nutrition and physical activity behaviors could effectively reduce risk factors associated with type 2 diabetes in middle school children. Pilot and formative studies were conducted to inform the development of the intervention components and the process evaluation methods for the main trial. During the main trial, both qualitative and quantitative assessments monitored the fidelity of the intervention and motivated modifications to improve intervention delivery. Structured observations of physical education classes, total school food environments, classroom-based educational modules, and communications and promotional campaigns provided verification that the intervention was delivered as intended. Interviews and focus groups yielded a multidimensional assessment of how the intervention was delivered and received, as well as identifying the barriers to and facilitators of the intervention across and within participating schools. Interim summaries of process evaluation data were presented to the study group as a means of ensuring standardization and quality of the intervention across the seven participating centers. Process evaluation methods and procedures documented the fidelity with which the HEALTHY study was implemented across 21 intervention schools and identified ways in which the intervention delivery might be enhanced throughout the study.

Effect of a moderately hypoenergetic Mediterranean diet and exercise program on body cell mass and cardiovascular risk factors in obese women.

OBJECTIVE: To assess the effects of a moderately hypoenergetic Mediterranean diet (MHMD) and exercise program on body cell mass (BCM) and cardiovascular disease risk factors in obese women. SUBJECTS/METHODS: Forty-seven obese women, 39.7+/-13.2 years of age, with a body mass index (BMI)=30.7+/-6.0 kg/m(2), completed the study. The following were measured at baseline, 2 and 4 months: BCM, BCM index (BCMI), body weight, BMI, fat-free mass (FFM), fat mass (FM), total body water (TBW), extracellular water (ECW) and intracellular water (ICW) using bioelectrical impedance analysis; fasting blood glucose (FBG), serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG) concentrations; systolic (SBP) and diastolic (DBP) blood pressure. RESULTS: Body weight, BMI, FM, TC and TG significantly decreased (P<0.001; P<0.002 (TG)) at 2 and 4 months. FFM, TBW, ECW, FBG and DBP significantly decreased at 2 months (P<0.05 (FFM); P<0.001). LDL-C significantly decreased (P<0.001), while HDL-C significantly increased (P<0.002) at 4 months. BCM, BCMI, ICW and SBP remained stable over time. CONCLUSION: BCM was preserved and cardiovascular disease risk factors improved in obese women placed on a MHMD and exercise program for 4 months.

Assessment of total body potassium in healthy Italian men.

BACKGROUND: Whole-body (40)K counting is a valuable tool for assessing cellular changes in body composition with ageing. AIM: The objectives of this study were to assess total body potassium (TBK) and body cell mass (BCM) differences with age, and to compare TBK and BCM between individuals with a body mass index (BMI) < 25 kg m(-2) versus > 25 kg m(-2). SUBJECTS AND METHODS: Body composition of 840 healthy Italian men, 18-70 years of age, was measured by whole-body counting of (40)K. BCM (kg) was calculated as 0.00833 x TBK (mmol). RESULTS: Body weight did not differ among groups. TBK, TBK/height, TBK/body weight, and BCM were significantly lower for the 51-70-year-old group compared with all other groups. The 51-70-year-old group with a BMI < 25 kg m(-2) had significantly lower TBK, TBK/height, and BCM than all other decades with a BMI < 25 kg m(-2); whereas TBK/body weight was significantly lower than the 18-30 and 31-40-year-old groups. The 51-70-year-old group with a BMI > 25 kg m(-2) had significantly lower TBK, TBK/height, TBK/body weight, and BCM than all other decades with a BMI > 25 kg m(-2). CONCLUSION: TBK and BCM decrease significantly with ageing, which could result in decreased functional capacity in older adults.

Multicompartment model to assess body composition in professional water polo players.

AIM: The aim of this study was to compare differences between skinfold thicknesses (SK), bioelectrical impedance analysis (BIA), a 2-compartment model (2C), and 2, 3-compartment models (3C) of percent body fat (%BF) assessment with a 4-compartment model (4C) in professional water polo athletes. METHODS: Ten male subjects, 18 to 29 years of age, participated in this study. Under water weighing, deuterium dilution, and dual-energy X-ray absorptiometry (DXA) were used to provide the required values for the models. The two, 3C models used were established by Withers et al. (3C-W) and by the DXA manufacturers (3C-DXA). 4C was also established by Withers et al. RESULTS: There were no significant differences between 2C, 3C-W, and 3C-DXA when compared with 4C (criterion model). There were no significant differences between 2C and 3C-W. %BF was significantly greater using 2C compared with 3C-DXA. %BF derived from SK and BIA were significantly greater than all other METHODS: 4C was best correlated with 3C-W (R2=0.998), followed by 2C (R2=0.806), 3C-DXA (R2=0.5071), SK (R2=0.2945), and BIA (R2=0.2377). CONCLUSION: We conclude that 2C and 3C-W assess %BF equally as well as 4C; however, SK and BIA significantly over-estimated %BF in water polo athletes.

Effect of different sports on body cell mass in highly trained athletes.

The objective of this study was to verify the impact of various sports on body cell mass (BCM). Ninety-eight male subjects, 17-33 years of age, participated in the study. The sample included athletes from three professional Italian football (soccer) teams, representing three different divisions (A, n=16; B, n=14; and C, n=18), judo athletes (J, n=10), and water polo athletes (W, n=14) who all competed at the national level. Twenty-six age-matched individuals served as the control group (CG). Fat-free mass (FFM), fat mass (FM), percent body fat (%BF), and BCM were assessed using bioimpedance spectroscopy (BIS). There were no significant differences in body weight and FFM among the groups. A and B were significantly taller than J and CG. B had a significantly lower body mass index (BMI; kg/m(2)) than CG, while C had a significantly lower BMI than J and CG. CG had a significantly greater FM and %BF than A, B, and C. C had a significantly lower BCM than Aand B. CG had a significantly lower BCM than A, B, J, and W. In conclusion, differences in BCM exist among athletes of different sports, and among athletes within the same sport who compete at different levels.

American College of Sports Medicine position stand. Appropriate intervention strategies for weight loss and prevention of weight regain for adults.

In excess of 55% of adults in the United States are classified as either overweight (body mass index = 25-29.9 kg.m(-2)) or obese (body mass index > or = 30 kg.m(-2)). To address this significant public health problem, the American College of Sports Medicine recommends that the combination of reductions in energy intake and increases in energy expenditure, through structured exercise and other forms of physical activity, be a component of weight loss intervention programs. An energy deficit of 500-1000 kcal.d-1 achieved through reductions in total energy intake is recommended. Moreover, it appears that reducing dietary fat intake to <30% of total energy intake may facilitate weight loss by reducing total energy intake. Although there may be advantages to modifying protein and carbohydrate intake, the optimal doses of these macronutritents for weight loss have not been determined. Significant health benefits can be recognized with participation in a minimum of 150 min (2.5 h) of moderate intensity exercise per week, and overweight and obese adults should progressively increase to this initial exercise goal. However, there may be advantages to progressively increasing exercise to 200-300 min (3.3-5 h) of exercise per week, as recent scientific evidence indicates that this level of exercise facilitates the long-term maintenance of weight loss. The addition of resistance exercise to a weight loss intervention will increase strength and function but may not attenuate the loss of fat-free mass typically observed with reductions in total energy intake and loss of body weight. When medically indicated, pharmacotherapy may be used for weight loss, but pharmacotherapy appears to be most effective when used in combination with modifications of both eating and exercise behaviors. The American College of Sports Medicine recommends that the strategies outlined in this position paper be incorporated into interventions targeting weight loss and the prevention of weight regain for adults.

Effect of chromium supplementation and exercise on body composition, resting metabolic rate and selected biochemical parameters in moderately obese women following an exercise program.

OBJECTIVE: To investigate the effect of chromium picolinate (CP) supplementation on body composition, resting metabolic rate (RMR), selected biochemical parameters and iron and zinc status in moderately obese women participating in a 12-week exercise program. METHODS: Forty-four women, 27 to 51 years of age, were randomly assigned to two groups based on their body mass index. Subjects received either 400 microg/day of chromium as a CP supplement or a placebo in double-blind fashion and participated in a supervised weight-training and walking program two days per week for 12 weeks. Body composition and RMR were measured at baseline, 6 and 12 weeks. Selected biochemical parameters and iron and zinc status were measured at baseline and 12 weeks. RESULTS: Body composition and RMR were not significantly changed by CP supplementation. No significant differences in fasting plasma glucose, serum insulin, plasma glucagon, serum C-peptide and serum lipid concentrations or in iron and zinc indices were found between the two groups over time. Serum total cholesterol concentration significantly decreased (p = 0.0016) over time for all subjects combined, probably as a result of the exercise training. Exercise training significantly reduced total iron binding capacity (TIBC) by 3% for all subjects combined (p = 0.001 1). CONCLUSIONS: Twelve weeks of 400 microg/day of chromium as a CP supplement did not significantly affect body composition, RMR, plasma glucose, serum insulin, plasma glucagon, serum C-peptide and serum lipid concentrations or iron and zinc indices in moderately obese women placed on an exercise program. The changes in serum total cholesterol levels and TIBC were a result of the exercise program.

Chromium, exercise, and body composition.

Chromium is an essential trace element involved in the metabolism of carbohydrates, lipids, and proteins mainly by increasing the efficiency of insulin. Chromium deficiency affects the maintenance of normal glucose tolerance and healthy lipid profiles. The Estimated Safe and Adequate Daily Dietary Intake for chromium is 50 to 200 microg/d for adults. However, the dietary intake of chromium in humans is often suboptimal. Chromium assessment has proven to be a challenge due to the low amounts of chromium present in biological materials and the absence of a reliable indicator of chromium status. Recently, chromium has been touted as an agent for increasing lean body mass and decreasing percent body fat. This article reviews the various studies that have been conducted to investigate the relationship of chromium with exercise and body composition.

Effect of iron supplementation on thyroid hormone levels and resting metabolic rate in two college female athletes: a case study.

Iron plays an important role in thyroid hormone metabolism; thus, iron deficiency anemia may lead to alterations in resting metabolic rate (RMR). Based on this premise, two iron-deficient-anemic female athletes, 18 (A1) and 21 (A2) years of age, were supplemented with 23 mg/day of elemental iron to assess its effects on iron and thyroid hormone status and RMR at 0, 8, and 16 weeks. Anemia was clinically corrected in both subjects (hemoglobin: A1 = 11.0 to 13.0 to 12.6 g/dL and A2 = 11.5 to 13.9 to 12.6 g/dL, 0 to 8 to 16 weeks, respectively). Serum ferritin (SF) concentration also improved in both subjects (A1: 5.0 to 11.0 to 15.0 ng/dL and A2: 5.0 to 16.0 to 20.0 ng/dL; 0 to 8 to 16 weeks, respectively); however, 16 weeks of iron supplementation did not fully replete iron stores. A2 increased dietary iron and ascorbic acid intakes from 8 to 16 weeks, possibly accounting for her higher SF concentrations. RMR and total thyroxine changed over time: A1 increased while A2 decreased in these variables. Although clinical correction of iron deficiency anemia occurred after 16 weeks of low-level iron supplementation, RMR and thyroid hormone metabolism were oppositely affected in the two subjects.

Zinc, exercise, and thyroid hormone function.

During the last 3 decades, remarkable advances have taken place in the field of zinc metabolism. Thirty years ago, only three enzymes that required zinc for their activities were identified; today more than 200 such enzymes have been classified. Zinc plays a vital role in human nutrition and biochemical function. Prior to 1963, zinc deficiency in humans was unknown. Today, it is recognized that a nutritional deficiency of zinc is common throughout the world, including the U.S.A marginal deficiency of zinc appears to be prevalent in many segments of populations in developed countries, and more severe deficiencies are widespread in many parts of the world. Therefore, it is important that proper steps to correct zinc deficiency are taken. However, the assessment of zinc nutriture has always proven to be a difficult problem because no reliable measure of zinc status currently exists. More recently, it has been recognized that zinc may play an important role in thyroid hormone metabolism, although the exact mechanism by which zinc affects thyroid hormone function is far from clear. In addition, exercise has been shown to alter zinc status. This review will focus on the relationship among zinc status, exercise, and thyroid hormone function.

Iron, thermoregulation, and metabolic rate.

Iron plays an important role, not only in oxygen delivery to the tissues, but also as a cofactor with several enzymes involved in energy metabolism and thermoregulation. As a result, much research has been dedicated to understanding the ramifications of iron depletion and iron deficiency anemia on the physiological functions of these enzymes. There is evidence to suggest that iron depletion and iron deficiency anemia cause physiological changes in the body not only during exercise, but also under resting conditions. Both rat and human studies have produced results revealing elevated levels of norepinephrine in the blood and urine of iron-deficient anemic subjects. These studies also provide evidence to suggest that elevation in metabolic rate may ultimately lead to slower growth rates and lower body weights in iron-deficient anemic animals and humans. The focus of this review is on the effects of iron deficiency on metabolic rate and thermoregulation. Prior to this discussion, a brief background on iron is presented.

Preexercise feeding in untrained adolescent boys does not affect responses to endurance exercise or performance.

The effects of preexercise feeding on responses to endurance exercise and performance were investigated. Untrained adolescent boys (N = 13, age 14.9 +/- 0.5 years) completed three endurance test sessions separated by a minimum of 72 hr. Each session consisted of 75 min of cycling at 60% of VO2 max followed by a high-intensity performance test. Dietary conditions were a candy bar (C1: 280 kcal, 36 g CHO), fat-free fig bars (C2: 200 kcal, 44 g CHO), and a nonnutritive sweetened drink (C3: placebo), ingested 10 min prior to exercise. Respiratory gases, heart rate, blood glucose, and lactate concentrations were measured throughout the test. ANOVA results revealed significant time effects for all variables; however, no differences were seen among the conditions. Performance times, 311.9 +/- 38.5 s in C1, 316.2 +/- 37.3 s in C2, and 328.1 +/- 46.4 s in C3, were not significantly different among conditions. Thus, preexercise feeding did not affect responses to endurance exercise or performance in adolescent boys.

Effect of boron supplementation on blood and urinary calcium, magnesium, and phosphorus, and urinary boron in athletic and sedentary women.

It has been reported that boron may be beneficial for optimal calcium metabolism and, thus, optimal bone metabolism. Therefore, we designed a study to determine the effects of boron supplementation on blood and urinary minerals in athletic subjects and sedentary control subjects consuming self-selected typical Western diets. Serum phosphorus concentrations were lower in boron-supplemented subjects than in placebo-supplemented subjects. Compared with all other subjects, serum magnesium concentrations were greatest in the sedentary control subjects supplemented with boron and increased with time in all subjects. Exercise training diminished changes in serum phosphorus concentrations caused by boron supplementation. Calcium excretion increased over time in all groups combined, and boron excretion increased over time in all boron-supplemented subjects. The findings suggest that boron supplementation modestly affected mineral status, and exercise modified the effects of boron supplementation on serum minerals.

Effects of boron supplementation on bone mineral density and dietary, blood, and urinary calcium, phosphorus, magnesium, and boron in female athletes.

The effects of boron supplementation on blood and urinary minerals were studied in female college students--17 athletes and 11 sedentary controls--over a one-year period. The athletes had lower percent body fat and higher aerobic capacities than sedentary controls. Athletic subjects consumed more boron in their normal diets than sedentary subjects; all other dietary measures were similar between the two groups. The athletes showed a slight increase in bone mineral density, whereas the sedentary group showed a slight decrease. Serum phosphorus concentrations were lower in boron-supplemented subjects than in subjects receiving placebos, and were lower at the end of the study period than during baseline analysis. Activity depressed changes in serum phosphorus in boron-supplemented subjects. Serum magnesium concentrations were greatest in the sedentary controls whose diets were supplemented with boron, and increased with time in all subjects. A group x supplement interaction was observed with serum magnesium; exercise in boron-supplemented subjects lowered serum magnesium. In all subjects, calcium excretion increased over time; in boron-supplemented subjects, boron excretion increased over time. In all subjects, boron supplementation affected serum phosphorus and magnesium, and the excretion of urinary boron.

The relationship between boron and magnesium status and bone mineral density in the human: a review.

Osteoporosis is a disease that characteristically afflicts postmenopausal women. It is estimated that millions of people are plagued yearly with this debilitating disease. Associated health care costs are in the billions of dollars, annually. Much research has been conducted in the area of osteoporosis and mineral supplementation, mainly focusing on calcium and vitamin D. Nonetheless, more recent studies have reported possible improvements in bone mineral density in women who were supplemented with the ultratrace mineral, boron. Boron may play a role in bone metabolism, but its role is most likely to be associated with its interactions with other minerals and vitamins such as calcium, magnesium and vitamin D. Although the focus of this review will be to discuss the interactive role of boron with magnesium and bone metabolism, some discussion of its interactive role with vitamin D is also necessary.