Objective: Our goal was to evaluate the effect of a low-salt diet on urinary calcium excretion in patients affected by idiopathic calcium nephrolithiasis.

Design: Patients affected by idiopathic calcium stone disease and hypercalciuria (>300 mg Ca/d in men and >250 mg Ca/d in women) were randomly assigned to receive either water therapy alone (control diet) or water therapy and a low-salt diet (low-sodium diet) for 3 mo. Twenty-four-hour urine samples were obtained twice from all patients: one sample at baseline on a free diet and one sample after 3 mo of treatment.

Results: A total of 210 patients were randomly assigned to receive a control diet (n = 102) or a low-sodium diet (n = 108); 13 patients (2 on the control diet, 11 on the low-sodium diet) withdrew from the trial. At the follow-up visit, patients on the low-sodium diet had lower urinary sodium (mean ± SD: 68 ± 43 mmol/d at 3 mo compared with 228 ± 57 mmol/d at baseline; P < 0.001). Concomitant with this change, they showed lower urinary calcium (271 ± 86 mg/d at 3 mo compared with 361 ± 129 mg/d on the control diet, P < 0.001) and lower oxalate excretion (28 ± 8 mg/d at 3 mo compared with 32 ± 10 mg/d on the control diet, P = 0.001). Urinary calcium was within the normal range in 61.9% of the patients on the low-salt diet and in 34.0% of those on the control diet (difference: +27.9%; 95% CI: +14.4%, +41.3%; P < 0.001).

Conclusion: A low-salt diet can reduce calcium excretion in hypercalciuric stone formers. This trial was registered at clinicaltrials.gov as NCT01005082.

Objective: We examined the association between dietary vitamin B-12 intake and biomarkers of vitamin B-12 status.

Design: Dietary vitamin B-12 intake was estimated, and biomarkers of vitamin B-12 status were measured, in healthy men and women (n = 299; age range: 18–50 y) who were recruited from a Florida community. The National Cancer Institute Diet History Questionnaire was used. Plasma cobalamin, total transcobalamin, holo-transcobalamin, methylmalonic acid (MMA), total homocysteine (tHcy), and autoantibodies against intrinsic factor (IF) and Helicobacter pylori were analyzed in blood samples.

Results: Antibodies to H. pylori were detected in 12% of subjects (35/299), and negative results for IF antibodies were obtained for all subjects. The intake of vitamin B-12 correlated significantly with cobalamin, holo-transcobalamin, MMA, and tHcy. Subjects were divided into quintiles on the basis of their dietary vitamin B-12 intake (range: 0.42–22.7 µg/d), and biomarkers of vitamin B-12 status were plotted against estimated dietary vitamin B-12 intake. All biomarkers appeared to level off at a daily dietary vitamin B-12 intake between 4.2 and 7.0 µg.

Conclusion: In persons with normal absorption, our data indicate that an intake of 4–7 µg vitamin B-12/d is associated with an adequate vitamin B-12 status, which suggests that the current RDA of 2.4 µg vitamin B-12/d might be inadequate for optimal biomarker status even in a healthy population between 18 and 50 y of age.

Objective: The purpose of this study was to compare the effect of a low-carbohydrate diet (≤20 g/d) with a high-carbohydrate diet (55% of total energy intake) on fasting and hourly metabolic variables during active weight loss.

Design: Healthy, obese adults (n = 32; 22 women, 10 men) were randomly assigned to receive either a carbohydrate-restricted diet [High Fat; mean ± SD body mass index (BMI; in kg/m²): 35.8 ± 2.9] or a calorie-restricted, low-fat diet (High Carb; BMI: 36.7 ± 4.6) for 6 wk. A 24-h in-patient feeding study was performed at baseline and after 6 wk. Glucose, insulin, free fatty acids (FFAs), and triglycerides were measured hourly during meals, at regimented times. Remnant lipoprotein cholesterol was measured every 4 h.

Results: Patients lost a similar amount of weight in both groups (P = 0.57). There was an absence of any diet treatment effect between groups on fasting triglycerides or on remnant lipoprotein cholesterol, which was the main outcome. Fasting insulin decreased (P = 0.03), and both fasting (P = 0.040) and 24-h FFAs (P < 0.0001) increased within the High Fat group. Twenty-four-hour insulin decreased (P < 0.05 for both groups). Fasting LDL cholesterol decreased in the High Carb group only (P = 0.003). In both groups, the differences in fasting and 24-h FFAs at 6 wk were significantly correlated with the change in LDL cholesterol (fasting FFA: r = 0.41, P = 0.02; 24-h FFA: r = 0.52, P = 0.002).

Conclusions: Weight loss was similar between diets, but only the high-fat diet increased LDL-cholesterol concentrations. This effect was related to the lack of suppression of both fasting and 24-h FFAs.

Objective: Our objective was to evaluate the reproducibility of ad libitum energy intake with the use of a computerized vending machine system.

Design: Twelve individuals (mean ± SD: 36 ± 8 y old; 41 ± 8% body fat) consumed a weight-maintaining diet for 3 d; subsequently, they self-selected all food with the use of a computerized vending machine system for an additional 3 d. Mean daily energy intake was calculated from the actual weight of foods consumed and expressed as a percentage of weight-maintenance energy needs (%WMEN). Subjects repeated the study multiple times during 2 y. The within-person reproducibility of energy intake was determined through the calculation of the intraclass correlation coefficients (ICCs) between visits.

Results: Daily energy intake for all subjects was 5020 ± 1753 kcal during visit 1 and 4855 ± 1615 kcal during visit 2. There were no significant associations between energy intake and body weight, body mass index, or percentage body fat while subjects used the vending machines, which indicates that intake was not driven by body size or need. Despite overconsumption (%WMEN = 181 ± 57%), the reproducibility of intake between visits, whether expressed as daily energy intake (ICC = 0.90), %WMEN (ICC = 0.86), weight of food consumed (ICC = 0.87), or fat intake (g/d; ICC = 0.87), was highly significant (P < 0.0001).

Conclusion: Although ad libitum energy intake exceeded %WMEN, the within-person reliability of this intake across multiple visits was high, which makes this a reproducible method for the measurement of ad libitum intake in subjects who reside in a research unit. This trial was registered at clinicaltrials.gov as NCT00342732.

Objective: The objective was to investigate whether having a choice between 2 vegetables enhances children's vegetable liking and consumption.

Design: Three hundred three children (age: 4–6 y) were randomly assigned to receive 1 of 3 dinner conditions in a restaurant setting. Two similarly liked vegetables were presented, after which the child had no choice, a premeal choice, or an at-meal choice. Subsequently, the dinner was consumed with one parent present. Comparisons between the 3 conditions regarding children's meal experience, vegetable liking, and vegetable consumption were made by using analysis of variance and Kruskal-Wallis tests.

Results: Children's vegetable consumption did not differ (P = 0.54) between the conditions as follows: 56 ± 45 g in the no-choice condition, 51 ± 46 g in the premeal-choice condition, and 49 ± 47 g in the at-meal-choice condition. In the no-choice condition, high-reactant children (who are more sensitive to psychological, persuasive pressure) consumed fewer vegetables (45 ± 42 g) than did low-reactant children (73 ± 43 g; P = 0.04). Vegetable liking was similar in all 3 conditions (P = 0.43). Children appreciated being able to choose in the premeal-choice condition.

Conclusions: A premeal choice between 2 vegetables was appreciated by the children but did not increase their vegetable liking and consumption. The no-choice condition decreased vegetable consumption in high-reactant children. Future research should investigate the effects of choice-offering in the long term and in more familiar eating settings. This trial was registered at controlled-trials.com as ISRCTN03035138.

Objective: The objective was to estimate usual folic acid intake above the UL and adjusted serum and red blood cell folate, vitamin B-12, methylmalonic acid, and homocysteine concentrations among US adults by 3 major folic acid intake sources—enriched cereal-grain products (ECGP), ready-to-eat cereals (RTE), and supplements (SUP)—categorized into 4 mutually exclusive consumption groups.

Design: We used data from the National Health and Nutrition Examination Survey (NHANES) 2003–2006 (n = 8258).

Results: Overall, 2.7% (95% CI: 1.9%, 3.5%) of adults consumed more than the UL of folic acid. The proportions of those who consumed folic acid from ECGP only, ECGP+RTE, ECGP+SUP, and ECGP+RTE+SUP were 42%, 18%, 25%, and 15%, respectively. Of 60% of adults who did not consume supplements containing folic acid (ECGP only and ECGP+RTE), 0% had intakes that exceeded the UL. Of 34% and 6% of adults who consumed supplements with an average of ≤400 and >400 µg folic acid/d, <1% and 47.8% (95% CI: 39.6%, 56.0%), respectively, had intakes that exceeded the UL. Consumption of RTE and/or supplements with folic acid was associated with higher folate and vitamin B-12 and lower homocysteine concentrations, and consumption of supplements with vitamin B-12 was associated with lower methylmalonic acid concentrations (P < 0.001).

Conclusion: At current fortification levels, US adults who do not consume supplements or who consume an average of ≤400 µg folic acid/d from supplements are unlikely to exceed the UL in intake for folic acid.

Objective: The objective was to perform a systematic review and meta-analysis of RCTs of GTCs on anthropometric variables, including body mass index (BMI), body weight, waist circumference (WC), and waist-to-hip ratio (WHR).

Design: A systematic literature search of MEDLINE, EMBASE, CENTRAL, and the Natural Medicines Comprehensive Database was conducted through April 2009. RCTs that evaluated GTCs with or without caffeine and that reported BMI, body weight, WC, or WHR were included. The weighted mean difference of change from baseline (with 95% CIs) was calculated by using a random-effects model.

Results: Fifteen studies (n = 1243 patients) met the inclusion criteria. On meta-analysis, GTCs with caffeine decreased BMI (–0.55; 95% CI: –0.65, –0.40), body weight (–1.38 kg; 95% CI: –1.70, –1.06), and WC (–1.93 cm; 95% CI: –2.82, –1.04) but not WHR compared with caffeine alone. GTC ingestion with caffeine also significantly decreased body weight (–0.44 kg; 95% CI: –0.72, –0.15) when compared with a caffeine-free control. Studies that evaluated GTCs without concomitant caffeine administration did not show benefits on any of the assessed anthropometric endpoints.

Conclusions: The administration of GTCs with caffeine is associated with statistically significant reductions in BMI, body weight, and WC; however, the clinical significance of these reductions is modest at best. Current data do not suggest that GTCs alone positively alter anthropometric measurements.

Objective: We sought to determine the effect of vitamin D status on health outcomes.

Design: Healthy community-dwelling women (n = 1471) with a mean age of 74 y were followed in a 5-y trial of calcium supplementation. 25(OH)D was measured at baseline in all women. Skeletal and nonskeletal outcomes were evaluated according to seasonally adjusted vitamin D status at baseline.

Results: Fifty percent of women had a seasonally adjusted 25(OH)D concentration <50 nmol/L. These women were significantly older, heavier, and less physically active and had more comorbidities than women with a seasonally adjusted 25(OH)D concentration ≥50 nmol/L. Women with a seasonally adjusted 25(OH)D concentration <50 nmol/L had an increased incidence of stroke and cardiovascular events that did not persist after adjustment for between-group differences in age or comorbidities. Women with a seasonally adjusted 25(OH)D concentration <50 nmol/L were not at increased risk of adverse consequences for any musculoskeletal outcome, including fracture, falls, bone density, or grip strength or any nonskeletal outcomes, including death, myocardial infarction, cancer, heart failure, diabetes, or adverse changes in blood pressure, weight, body composition, cholesterol, or glucose.

Conclusions: Vitamin D insufficiency is more common in older, frailer women. Community-dwelling older women with a seasonally adjusted 25(OH)D concentration <50 nmol/L were not at risk of adverse outcomes over 5 y after control for comorbidities. Randomized placebo-controlled trials are needed to determine whether vitamin D supplementation in individuals with vitamin D insufficiency influences health outcomes. This trial was registered at www.anzctr.org.au as ACTRN 012605000242628.

Objective: This study aimed to examine the association between beverage consumption and 5-y body weight change in 2294 adolescents.

Design: Project EAT (Eating Among Teens) is a 5-y longitudinal study of eating patterns among adolescents. Surveys were completed in 1998–1999 (time 1) and in 2003–2004 (time 2). Multivariable linear regression was used to examine the association between beverage consumption at time 2 and change in body mass index from time 1 to time 2, with adjustments for age, socioeconomic status, race, cohort, physical activity, sedentary behavior, coffee, tea, time 1 body mass index, and beverage variables.

Results: In prospective analyses, consumption of beverages was not associated with weight gain, except for consumption of low-calorie soft drinks (positive association, P = 0.002) and white milk (inverse association, P = 0.03), but these associations did not appear to be a monotonic linear dose-response relation. The positive association with low-calorie soft drinks was no longer present after adjustment for dieting and parental weight-related concerns, which suggests that the use of low-calorie soft drinks is a marker for more general dietary behaviors and weight concerns.

Conclusions: We showed no association between sugar-sweetened beverage consumption, juice consumption, and adolescent weight gain over a 5-y period. A direct association between diet beverages and weight gain appeared to be explained by dieting practices. Adolescents who consumed little or no white milk gained significantly more weight than their peers who consumed white milk. Future research that examines beverage habits and weight among adolescents should address portion sizes, adolescent maturation, and dieting behaviors.

Objective: We examined the metabolic profiles of healthy human subjects after extended dietary standardization to see whether the inherent variation in the human metabolome could be decreased.

Design: A cohort of 10 healthy volunteers was admitted to a clinical research center for 2 wk of dietary standardization. Daily serum and urine samples and serum samples at a 2-wk follow-up visit were collected. The samples were analyzed by ¹H nuclear magnetic resonance (NMR) spectroscopy and multivariate statistical analyses.

Results: NMR spectra were collected to globally profile the higher-concentration metabolites (>µmol/L concentrations). Metabolic changes were observed in some serum samples after day 1 or the 2-wk follow-up visit. For each subject, the samples from all other days had similar profiles. The urinary metabolome reflected no effects from dietary standardization. Pooled 24-h urine samples were studied, which indicated that any normalization that does occur would do so in <24 h.

Conclusions: For both the urinary and serum metabolome, a single day of dietary standardization appears to provide all of the normalization that is achievable within the strict controls implemented in a clinical research setting. After 24 h, the subjects remain in their metabolic space; the remaining intra- and intersubject variations appear to be influenced by variables such as genetics, age, and lifestyle.