Hand-held indirect calorimeter offers advantages compared with prediction equations, in a group of overweight women, to determine resting energy expenditures and estimated total energy expenditures during research screening.

OBJECTIVE: To compare standardized prediction equations to a hand-held indirect calorimeter in estimating resting energy and total energy requirements in overweight women. DESIGN: Resting energy expenditure (REE) was measured by hand-held indirect calorimeter and calculated by prediction equations Harris-Benedict, Mifflin-St Jeor, World Health Organization/Food and Agriculture Organization/United Nations University (WHO), and Dietary Reference Intakes (DRI). Physical activity level, assessed by questionnaire, was used to estimate total energy expenditure (TEE). SUBJECTS: Subjects (n=39) were female nonsmokers older than 25 years of age with body mass index more than 25. STATISTICAL ANALYSES: Repeated measures analysis of variance, Bland-Altman plot, and fitted regression line of difference. A difference within +/-10% of two methods indicated agreement. RESULTS: Significant proportional bias was present between hand-held indirect calorimeter and prediction equations for REE and TEE (P<0.01); prediction equations overestimated at lower values and underestimated at higher values. Mean differences (+/-standard error) for REE and TEE between hand-held indirect calorimeter and Harris-Benedict were -5.98+/-46.7 kcal/day (P=0.90) and 21.40+/-75.7 kcal/day (P=0.78); between hand-held indirect calorimeter and Mifflin-St Jeor were 69.93+/-46.7 kcal/day (P=0.14) and 116.44+/-75.9 kcal/day (P=0.13); between hand-held indirect calorimeter and WHO were -22.03+/-48.4 kcal/day (P=0.65) and -15.8+/-77.9 kcal/day (P=0.84); and between hand-held indirect calorimeter and DRI were 39.65+/-47.4 kcal/day (P=0.41) and 56.36+/-85.5 kcal/day (P=0.51). Less than 50% of predictive equation values were within +/-10% of hand-held indirect calorimeter values, indicating poor agreement. CONCLUSIONS: A significant discrepancy between predicted and measured energy expenditure was observed. Further evaluation of hand-held indirect calorimeter research screening is needed.

Glucose and insulin responses to whole grain breakfasts varying in soluble fiber, beta-glucan: a dose response study in obese women with increased risk for insulin resistance.

BACKGROUND: A high intake of whole grains containing soluble fiber has been shown to lower glucose and insulin responses in overweight humans and humans with type 2 diabetes. AIM OF THE STUDY: We investigated the linearity of this response after consumption of 5 breakfast cereal test meals containing wheat and/or barley to provide varying amounts of soluble fiber, beta-glucan (0, 2.5, 5, 7.5 and 10 g). METHODS: Seventeen normoglycemic, obese women at increased risk for insulin resistance consumed 5 test meals within a randomized cross-over design after consuming controlled diets for 2 days. Blood samples for glucose and insulin response were obtained prior to and 30, 60, 120 and 180 min after consuming the test meals. RESULTS: Consumption of 10 g of beta-glucan significantly reduced peak glucose response at 30 min and delayed the rate of glucose response. Area under the curve for 2 h-postprandial glycemic response was not affected by beta-glucan content. However, peak and area under the curve of insulin responses were significantly affected by the beta-glucan amount in an inverse linear relationship. CONCLUSION: These data suggest that acute consumption of 10 g of beta-glucan is able to induce physiologically beneficial effects on postprandial insulin responses in obese women at risk for insulin resistance.

Alpha-actinin-3 (ACTN3) R577X polymorphism influences knee extensor peak power response to strength training in older men and women.

BACKGROUND: The alpha-actinin-3 (ACTN3) R577X polymorphism has been associated with muscle power performance in cross-sectional studies. METHODS: We examined baseline knee extensor concentric peak power (PP) and PP change with approximately 10 weeks of unilateral knee extensor strength training (ST) using air-powered resistance machines in 71 older men (65 [standard deviation = 8] years) and 86 older women (64 [standard deviation = 9] years). RESULTS: At baseline in women, the XX genotype group had an absolute (same resistance) PP that was higher than the RR (p =.005) and RX genotype groups (p =.02). The women XX group also had a relative (70% of one-repetition maximum [1-RM]) PP that was higher than that in the RR (p =.002) and RX groups (p =.008). No differences in baseline absolute or relative PP were observed between ACTN3 genotype groups in men. In men, absolute PP change with ST in the RR (n = 16) group approached a significantly higher value than in the XX group (n = 9; p =.07). In women, relative PP change with ST in the RR group (n = 16) was higher than in the XX group (n = 17; p =.02). CONCLUSIONS: The results indicate that the ACTN3 R577X polymorphism influences the response of quadriceps muscle power to ST in older adults.

Use of complementary and alternative medicine for weight control in the United States.

OBJECTIVES: The purpose was to assess the prevalence and correlates of complementary and alternative medicine use for weight control. DESIGN: A list-assisted random-digit-dialed telephone survey of adults was conducted in the fall of 2002 (n = 11,211). The focus of the study was complementary and alternative medicine (CAM) use, other than dietary supplements, in the previous 12 months. SETTINGS/LOCATION: The sample of respondents was drawn from the total noninstitutionalized U.S. adult population residing in telephone-equipped locations. SUBJECTS: The sampling procedures were designed to obtain adequate representation of Hispanic and non-Hispanic black respondents. Data from the total sample of 11,211 were weighted to achieve an estimate of the U.S. population. Analyses focused on 372 people who had used CAM within the previous 12 months. RESULTS: Of the total, 3.3% (n = 372) had used a CAM therapy in the previous 12 months. Higher adjusted odds ratios for CAM use were found among respondents who were exercising for weight control; using a lower carbohydrate, higher protein diet; using a nonprescription weight-loss product(s); overweight; physically active; and not satisfied with one's body (adjusted for age, race, gender, education, and city size). The most often used therapies were yoga (57.4%), meditation (8.2%), acupuncture (7.7%), massage (7.5%), and Eastern martial arts (5.9%). CAM users used CAM therapies on their own (62.6%), in a group setting (26.8%) or with a CAM practitioner (10.6%). CONCLUSIONS: The use of CAM therapies other than dietary supplements for weight loss was relatively low. The most popular therapy was yoga, and the majority of CAM users used CAM therapies on their own. Persons who had used other weight loss methods had greater odds for using CAM in the previous 12 months, suggesting that CAM use is often added to other weight-loss strategies.

Use of nonprescription dietary supplements for weight loss is common among Americans.

OBJECTIVE: Dietary supplements are not recommended as part of a weight-loss program due to concerns about efficacy and safety. This study sought to assess prevalence and duration of nonprescription weight-loss supplement use, associated weight-control behaviors, discussion of use with a health care professional, and specific ingredient use. PARTICIPANTS AND DESIGN: Adults aged > or =18 years (n=9,403) completed a cross-sectional population-based telephone survey of health behaviors from September 2002 through December 2002. STATISTICAL ANALYSES PERFORMED: Both chi2 and t tests were conducted for categorical and mean comparisons and multiple variable logistic regression was used to determine significant predictors. RESULTS: An estimated 15.2% of adults (women 20.6%, men 9.7%) had ever used a weight-loss supplement and 8.7% had past year use (women 11.3%, men 6.0%); highest use was among women aged 18 to 34 years (16.7%). In regression models, use was equally prevalent among race/ethnic groups and education levels. One in 10 (10.2%) of users reported > or =12 month use, with less frequent long-term use in women (7.7%) than men (15.0%), P=0.01. Almost one third (30.2%) of users discussed use during the past year; 73.8% used a supplement containing a stimulant including ephedra, caffeine, and/or bitter orange. CONCLUSIONS: Use of supplements for losing weight seems to be common among many segments of the US adult population. Many adults are long-term users and most do not discuss this practice with their physician. Most of the weight-loss supplements taken contain stimulants. Qualified professionals should inquire about use of supplements for weight loss to facilitate discussion about the lack of efficacy data, possible adverse effects, as well as to dispel misinformation that may interfere with sound weight-management practices.

Availability of weight-loss supplements: Results of an audit of retail outlets in a southeastern city.

The sale of nonprescription weight-loss products accounts for millions of dollars spent by Americans trying to lose weight, yet there is little evidence for effectiveness and there are multiple safety concerns. The purpose of this study was to determine what products, and ingredients within products, were available at retail outlets in a metropolitan area. A purposive sampling strategy identified 73 retail outlets. An audit form was used to collect information from product labels. The audit identified 402 products containing 4,053 separate ingredients. The mean number of ingredients per product was 9.9+/-8.96 (range = 1 to 96). A database search was conducted regarding evidence for effectiveness, safety precautions, and side effects for the 10 ingredients that appeared most often across products. Modest evidence of effectiveness exists for green tea (Camellia sinensis), chromium picolinate, and ma huang (Ephedra major). For the remaining seven (ginger root [Zingiber officinale], guarana [Paullinia cupana], hydroxycitric acid [Garcinia cambogia], white willow [Salix alba], Siberian ginseng [Eleutherococcus senticosus], cayenne [Capsicum annuum], and bitter orange/zhi shi [Citrus aurantium]), inadequate or negative evidence exists. Although precautions and contraindications were found for all 10 ingredients, the strongest concerns in the literature appear for ma huang, bitter orange, and guarana. Our audit revealed numerous weight-loss products available to consumers, yet there is little evidence to support the effectiveness of the top 10 ingredients identified and many potential adverse reactions; therefore, food and nutrition professionals should discuss dietary supplement use with their clients.

Muscle-power quality: does sex or race affect movement velocity in older adults?

To determine sex and race differences in muscle power per unit of muscle contraction, knee-extensor muscle power normalized for knee-extensor muscle volume was measured in 79 middle-aged and older adults (30 men and 49 women, age range 50-85 years). Results revealed that women displayed a 38% faster peak movement velocity than men and African Americans had a 14% lower peak movement velocity than Whites of a similar age when expressed per unit of involved muscle (p < .001). As expected, men exhibited greater knee-extensor strength and peak power per unit of muscle than women, but women had a faster knee- extension movement velocity per unit of muscle than men at the same relative strength level. Moreover, African Americans had greater knee-extensor muscle volume than Whites but exhibited lower knee-extensor strength and lower movement velocity per unit of muscle when tested at the same relative strength levels.

Effects of moderate-velocity strength training on peak muscle power and movement velocity: do women respond differently than men?

The effects of a 10-wk unilateral knee extension strength training (ST) program on peak power (PP) and peak movement velocity (PV), at given absolute (force load) and relative (same % of 1 repetition maximum) resistances (loads), were examined in 30 older men [64 yr (7 SD)] and 32 older women [62 yr (6 SD)]. PP increased significantly in both men and women at the same absolute (P < 0.001) and relative loads (P < 0.01) with ST. Men had a significantly greater increase in relative PP than women with ST at 60% (P < 0.01) and 70% (P < 0.001) of 1 repetition maximum when covarying for baseline differences and age. However, when each subject was tested at the same absolute load and when PP was normalized for the muscle volume of the trained knee extensors (i.e., absolute muscle power quality), women increased by 9% (P < 0.05), whereas men did not change. Both men and women increased their absolute PV (P < 0.001) but decreased their relative PV significantly with ST (P < 0.05). However, when baseline values and age were covaried, women had significantly less of a decrease in relative PV quality with ST than men (P < 0.01), although the difference was small. These normalized data suggest that ST-induced increases in PP depend on muscular hypertrophy in men, but not in women, providing further support for the hypothesis developed from our previous report (Ivey FM, Tracy BL, Lemmer JT, NessAiver M, Metter EJ, Fozard JL and Hurley BF. J Gerontol A Biol Sci Med Sci 55: B152-B157, 2000) that improvements in muscle function with ST result from nonmuscle mass adaptations to a greater extent in women than men.

Vitamin D receptor FokI genotype influences bone mineral density response to strength training, but not aerobic training.

To determine the influence of the vitamin D receptor (VDR) gene FokI and BsmI genotype on bone mineral density response to two exercise training modalities, 206 healthy men and women (50-81 years old) were studied before and after approximately 5-6 months of either aerobic exercise training (AT) or strength training (ST). A totla of 123 subjects completed AT (51 men, 72 women) and 83 subjects completed ST (40 men, 43 women). DNA was extracted from blood samples of all subjects and genotyping was performed at the VDR FokI and BsmI locus to determine its association to training response. Total body, greater trochanter and femoral neck bone mineral density (BMD) were measured before and after both training programmes using dual-energy X-ray absorptiometry. VDR BsmI genotype was not significantly related to BMD at baseline or after ST or AT. However, VDR FokI genotype was significantly related to ST- but not AT-induced changes in femoral neck BMD (P < 0.05). The heterozygotes (Ff) in the ST group approached a significantly greater increase in femoral neck BMD (P = 0.058) compared to f homozygotes. There were no significant genotype relationships in the AT group. These data indicate that VDR FokI genotype may influence femoral neck BMD response to ST, but not AT.

Commercial portion-controlled foods in research studies: how accurate are label weights?

OBJECTIVE: The purpose of this study was to evaluate the reliability of label weights as surrogates for actual weights in commercial portion-controlled foods used in a research setting. DESIGN: Actual weights of replicate samples of 82 portion-controlled food items and 17 discrete units of food from larger packaging were determined over time. Comparison was made to the package label weights for the portion-controlled food items and the per-serving weights for the discrete units. SETTING: The study was conducted at the US Department of Agriculture's Beltsville Human Nutrition Research Center's Human Study Facility, which houses a metabolic kitchen and human nutrition research facility. MAIN OUTCOME MEASURES: The primary outcome measures were the actual and label weights of 99 food items consumed by human volunteers during controlled feeding studies. Statistical analyses performed The difference between label and actual weights was tested by the paired t test for those data that complied with the assumptions of normality. The Wilcoxon signed rank test was used for the remainder of the data. Compliance with federal guidelines for packaged weights was also assessed. RESULTS: There was no statistical difference between actual and label weights for only 37 food items. The actual weights of 15 portion-controlled food items were 1% or more less than label weights, making them potentially out of compliance with federal guidelines. CONCLUSIONS: With advance planning and continuous monitoring, well-controlled feeding studies could incorporate portion-controlled food items and discrete units, especially beverages and confectionery products. Dietetics professionals should encourage individuals with diabetes and others on strict dietary regimens to check actual weights of portion-controlled products carefully against package weights.

Accuracy of dietary recall using the USDA five-step multiple-pass method in men: an observational validation study.

OBJECTIVE: This observational validation study was conducted under controlled conditions to test the accuracy of dietary recall in normal weight, overweight, and obese men using the USDA five-step multiple-pass method for dietary recall. DESIGN: Cross-sectional analysis of actual and recalled intake of food during 1 day. SUBJECTS/SETTING: Forty-two men ranging in age from 21 to 65 years and in body mass index from 21 to 39 kg/m(2) who lived in the metropolitan Washington DC area were studied. INTERVENTION: The subjects selected and consumed all meals and snacks, for 1 day, from a wide variety of foods provided at a human study facility. MAIN OUTCOME MEASURES: Actual and recalled energy, protein, carbohydrate, and fat intakes were determined by direct observation and by a 24-hour dietary recall, respectively. Dietary recall was determined via telephone administration of the USDA five-step multiple-pass method the following day. STATISTICAL ANALYSES PERFORMED: Analysis of variance and covariance tested the overall accuracy of recall and the effect of body mass index on dietary recall. Bland-Altman plots were used to assess bias in recall of food intake. RESULTS: In this population of men, there were no significant differences between actual and recalled intakes of energy (3,294+/-111 and 3,541+/-124 kcal/day), protein (117+/-5 and 126+/-5 g/day), carbohydrate (414+/-16 and 449+/-16 g/day), or fat (136+/-7 and 146+/-8 g/day), respectively. Accuracy of recall was not related to body mass index in that the obese men recalled food intake as accurately as the nonobese men. The energy intake of these men was significantly correlated (r=0.57, P<.05) with their estimated energy requirements. Significant interindividual variation in accuracy of recall was found. CONCLUSIONS: Under controlled conditions, the USDA five-step multiple-pass method can accurately assess intakes of energy, protein, carbohydrate, and fat in a population of men regardless of their body mass index. Researchers and clinical dietitians need to continue to examine factors that influence underreporting and overreporting of food intake by the multiple-pass 24-hour recall method.

Effectiveness of the US Department of Agriculture 5-step multiple-pass method in assessing food intake in obese and nonobese women.

BACKGROUND: National surveys of food intake rely on the 24-h dietary recall method for assessing the nutrient intakes of Americans. OBJECTIVES: This observational validation study was conducted under controlled conditions to test the effectiveness of the US Department of Agriculture (USDA) 5-step multiple-pass method for dietary recall; to test the ability of normal weight, overweight, and obese women to recall food intake; and to test the accuracy of macronutrient recall. DESIGN: Women (n = 49) aged 21-65 y with a body mass index (in kg/m(2)) of 20-45 selected all meals and snacks for 1 d from a wide variety of foods. A 24-h dietary recall with the use of the USDA 5-step multiple-pass method was administered by telephone the following day. Analysis of variance and covariance tested the overall accuracy of recall and the effect of BMI on dietary recall. RESULTS: As a population, the women overestimated their energy and carbohydrate intakes by 8-10%. No significant differences between mean actual and recalled intakes of energy and the macronutrients were observed in the obese women. Normal-weight and overweight women significantly (P < 0.01) overestimated their energy, protein, and carbohydrate intakes. Recalled fat intake was not significantly different from actual intake in women across the BMI range studied. CONCLUSIONS: The USDA 5-step multiple-pass method effectively assessed mean energy intake within 10% of mean actual intake on the previous day. Obese women more accurately recalled food intake than did overweight and normal-weight women despite undereating on the day of the study.

Estimating energy expenditure from the Minnesota Leisure Time Physical Activity and Tecumseh Occupational Activity questionnaires - a doubly labeled water validation.

An accurate, simple method for assessing energy expenditure in individuals and in free-living populations continues to be elusive. To compare estimates of energy expenditure (EE) from a combination of two previously validated physical activity questionnaires: Tecumseh Occupational (EE(TEC)) and a 4-wk history version of the Minnesota Leisure Time Physical Activity that included household activities (EE(MNLTPA)) and EE from sleep (EE(SLEEP)), to EE obtained from doubly labeled water (EE(DLW)). We studied free-living males (n = 24) eating a controlled diet designed to maintain body weight and determined EE from doubly labeled water (DLW) during 14 days and EE from physical activity instruments used in epidemiological studies (EE(TEC) and EE(MNLTPA)). There was excellent agreement between EE(DLW) (mean +/- SEM, 13.55 +/- 0.38 MJ/d) and EE(TEC) + EE(MNLTPA) + EE(SLEEP) (EE(TOTAL1)) (13.79 +/- 0.89 MJ/d) with a difference of only 1.0% +/- 5.4%. When the EE from watching TV, reading, and childcare activities was added the total EE (EE(TOTAL2)) (14.87 +/- 0.90 MJ/D) overestimated EE(DLW) by 8.9% +/- 5.4%. Both of these estimates of EE had significant regressions against EE(DLW) (EE(TEC) + EE(MNLTPA) + EE(SLEEP), R(2) = 0.38, P < 0.001; EE(TOTAL2), R(2) = 0.39, P < 0.001). Men whose occupations involved significant intermittent moderate activity had the largest disagreement between EE(DLW) and estimates from the questionnaires. This investigation demonstrates that a combination of previously validated physical activity questionnaires can be used to accurately determine the mean energy expenditure of a population of employed males.

Comparison of energy expenditure estimates from doubly labeled water, a physical activity questionnaire, and physical activity records.

BACKGROUND: Various methods are used by epidemiologists to estimate the energy cost of physical activity; these include physical activity records and recalls. However, there is limited validation of these methods against the doubly labeled water technique for determining energy expenditure (EE). OBJECTIVE: We compared EE as estimated by indirect methods (physical activity records and recall questionnaires) used in epidemiologic studies with EE obtained from doubly labeled water (EE(DLW)) in free-living men. DESIGN: We determined EE(DLW), energy intake at weight maintenance, and EE from 7-d physical activity records (EE(Record)) and a 7-d physical activity recall questionnaire (EE(Recall)) in 24 men aged 41 plus minus 2.0 y ( plus minus SEM) with a body mass index (in kg/m(2)) of 25.1 plus minus 0.5. RESULTS: There was excellent agreement between EE(DLW) (13.27 plus minus 0.35 MJ/d) and energy intake (13.19 plus minus 0.36 MJ/d), with a difference of 0.5 plus minus 1.0% ( plus minus SE). The indirect measures of physical activity and EE were 14.17 plus minus 0.37 MJ/d for EE(Record) (difference from EE(DLW): 7.9 plus minus 3.2%) and 17.40 plus minus 1.45 MJ/d for EE(Recall) (difference from EE(DLW): 30.6 plus minus 9.9%). CONCLUSIONS: Seven-day physical activity records provide an acceptable estimate of EE in free-living adults compared with EE(DLW), but 7-d physical activity recalls have limited application to estimate daily EE. For optimal validity, the 7-d physical activity records require good subject compliance and the provision of careful instructions for their use.

Estimation of total body water by bioelectrical impedance analysis in blacks.

Several differences exist between the body composition of blacks and whites. This study was designed to investigate the applicability of bioelectrical impedance analysis (BIA) in blacks, using prediction equations developed in whites. A multiple regression equation developed on 79 white adults, using deuterium oxide dilution space total body water (D2 O-TBW) as the reference method, was prospectively applied to 88 blacks aged 19-50 years. Although the regression line of D2 O-TBW on BIA-TBW was not significantly different from the line of identity (r = 0.98, SEE = 1.71 liters), mean TBW was significantly underestimated by 0.84 liter. Other BIA equations from the literature also underestimated D2 O-TBW in blacks, except for an equation developed on a mixed black and white population. Multiple regression analysis on the data of the black and white subjects combined showed that race, offered as a separate independent variable, improved the correlation with D2 O-TBW slightly but significantly (P < 0.01). It was concluded that BIA may be valuable in the assessment of body composition in blacks as well as in whites. In this study a small underestimation of TBW occurred in blacks, using (BIA) equations from whites. This may be due to racial differences in body composition or to factors unrelated to ethnicity.