Linda Easter

Effect of exercise intensity on abdominal fat loss during calorie restriction in overweight and obese postmenopausal women: a randomized, controlled trial

BACKGROUND Exercise intensity may affect the selective loss of abdominal adipose tissue. OBJECTIVE This study showed whether aerobic exercise intensity affects the loss of abdominal fat and improvement in cardiovascular disease risk factors under conditions of equal energy deficit in women with abdominal obesity. DESIGN This was a randomized trial in 112 overweight and obese [body mass index (in kg/m(2)): 25-40; waist circumference >88 cm], postmenopausal women assigned to one of three 20-wk interventions of equal energy deficit: calorie restriction (CR only), CR plus moderate-intensity aerobic exercise (CR + moderate-intensity), or CR plus vigorous-intensity exercise (CR + vigorous-intensity). The diet was a controlled program of underfeeding during which meals were provided at individual calorie levels (approximately 400 kcal/d). Exercise (3 d/wk) involved treadmill walking at an intensity of 45-50% (moderate-intensity) or 70-75% (vigorous-intensity) of heart rate reserve. The primary outcome was abdominal visceral fat volume. RESULTS Average weight loss for the 95 women who completed the study was 12.1 kg (+/-4.5 kg) and was not significantly different across groups. Maximal oxygen uptake ( O(2)max) increased more in the CR + vigorous-intensity group than in either of the other groups (P < 0.05). The CR-only group lost relatively more lean mass than did either exercise group (P < 0.05). All groups showed similar decreases in abdominal visceral fat (approximately 25%; P < 0.001 for all). However, changes in visceral fat were inversely related to increases in O(2)max (P < 0.01). Changes in lipids, fasting glucose or insulin, and 2-h glucose and insulin areas during the oral-glucose-tolerance test were similar across treatment groups. CONCLUSION With a similar amount of total weight loss, lean mass is preserved, but there is not a preferential loss of abdominal fat when either moderate- or vigorous-intensity aerobic exercise is performed during caloric restriction. This trial was registered at (ClinicalTrials.gov) as: NCT00664729.

Lean Mass Loss Is Associated with Low Protein Intake during Dietary-Induced Weight Loss in Postmenopausal Women

The health and quality-of-life implications of overweight and obesity span all ages in the United States. We investigated the association between dietary protein intake and loss of lean mass during weight loss in postmenopausal women through a retrospective analysis of a 20-week randomized, controlled diet and exercise intervention in women aged 50 to 70 years. Weight loss was achieved by differing levels of caloric restriction and exercise. The diet-only group reduced caloric intake by 2,800 kcal/week, and the exercise groups reduced caloric intake by 2,400 kcal/week and expended approximately 400 kcal/week through aerobic exercise. Total and appendicular lean mass was measured using dual energy x-ray absorptiometry. Linear regression analysis was used to examine the association between changes in lean mass and appendicular lean mass and dietary protein intake. Average weight loss was 10.8+/-4.0 kg, with an average of 32% of total weight lost as lean mass. Protein intake averaged 0.62 g/kg body weight/day (range=0.47 to 0.8 g/kg body weight/day). Participants who consumed higher amounts of dietary protein lost less lean mass and appendicular lean mass (r=0.3, P=0.01 and r=0.41, P<0.001, respectively). These associations remained significant after adjusting for intervention group and body size. Therefore, inadequate protein intake during caloric restriction may be associated with adverse body-composition changes in postmenopausal women.

EFFECTS OF DIETARY PROTEIN ON THE COMPOSITION OF WEIGHT LOSS IN POST-MENOPAUSAL WOMEN

Objectives: To determine whether a hypocaloric diet higher in protein can prevent the loss of lean mass that is commonly associated with weight loss.Design: An intervention study comparing a hypocaloric diet moderately high in protein to one lower in protein.Setting: Study measurements were taken at the Wake Forest University General Clinical Research Center (GCRC) and Geriatric Research Center (GRC).Participants: Twenty-four post-menopausal, obese women (mean age = 58 ± 6.6 yrs; mean BMI = 33.0 ± 3.6 kg/m2).Intervention: Two 20-week hypocaloric diets (both reduced by 2800 kcal/wk) were compared: one maintaining dietary protein intake at 30% of total energy intake (1.2–1.5 g/kg/d; HI PROT), and the other maintaining dietary protein intake at 15% of total energy (0.5–0.7 g/kg/d; LO PROT). The GCRC metabolic kitchen provided lunch and dinner meals which the women picked up 3 days per week and ate outside of the clinic.Measurements: Body composition, including total body mass, total lean mass, total fat mass, and appendicular lean mass, assessed by dual energy x-ray absorptiometry, was measured before and after the diet interventions.Results: The HI PROT group lost 8.4 ± 4.5 kg and the LO PROT group lost 11.4 ± 3.8 kg of body weight (p = 0.11). The mean percentage of total mass lost as lean mass was 17.3% ± 27.8% and 37.5% ± 14.6%, respectively (p = 0.03).Conclusion: Maintaining adequate protein intake may reduce lean mass losses associated with voluntary weight loss in older women.

Effect of Soda Consumption on Urinary Stone Risk Parameters

BACKGROUND AND PURPOSE Fluid consumption has been demonstrated to influence kidney stone formation. Studies have shown that consumption of cola may be a risk factor for stone disease, while fluids containing citric acid may attenuate stone activity. Diet was not always controlled in these investigations, however. We undertook a study to determine the impact of three different fluids on urinary stone risk factors. SUBJECTS AND METHODS Six healthy nonstone-forming adults were placed on a standardized metabolic diet and consumed three different types of fluid during three 5-day periods. There was a 2-day washout between each sequence. The three fluids administered during these periods were Le Bleu water, caffeine-free Diet Coke, and Fresca (citrate containing). These two soda preparations were chosen to prevent the known increase in calcium excretion promoted by carbohydrates and caffeine. Twenty-four hour urine specimens were collected on days 4 and 5 of each sequence. The following urinary parameters were measured: Volume, calcium, oxalate, creatinine, uric acid, citrate, sodium, magnesium, phosphorus, sulfate, urea nitrogen, pH, and supersaturation indices. A paired t test was used for statistical analysis. RESULTS Urinary volumes were significantly higher and supersaturation of calcium oxalate significantly lower compared with a self-selected dietary regimen. A decrease in uric acid was also seen in the Fresca cohort. There were no statistically significant differences for any of the urinary parameters. CONCLUSION There is no increased risk or benefit to consuming Fresca or caffeine-free Diet Coke compared with Le Bleu bottled water with respect to stone formation.

Metabolism of Fructose to Oxalate and Glycolate

Much attention has been recently directed at fructose consumption because of its association with obesity and subsequent development of chronic diseases. It was recently reported that an increased fructose intake increases the risk of forming kidney stones. It was postulated that fructose consumption may increase urinary oxalate, a risk factor for calcium oxalate kidney stone disease. However, conflicting results have been obtained in human studies examining the relationship between fructose metabolism and oxalate synthesis. To test whether fructose intake influences urinary excretions impacting kidney stone risk, healthy subjects consumed diets controlled in their contents of fructose, oxalate, calcium, and other nutrients. Subjects consumed diets containing 4, 13, and 21% of calories as fructose in a randomized order. No changes in the excretions of oxalate, calcium, and uric acid were observed. In vitro investigations with cultured liver cells incubated with (13)C-labeled sugars indicated that neither fructose nor glucose was converted to oxalate by these cells. Fructose metabolism accounted for 12.4 ± 1.6% of the glycolate detected in the culture medium and glucose 6.4 ± 0.9%. Our results suggest that mechanisms for stone risk associated with fructose intake may lie in factors other than those affecting the major stone risk parameters in urine.

Lifestyle interventions influence relative errors in self-reported diet intake of sodium and potassium.

PURPOSE To characterize the distribution of errors in self-reported sodium and potassium dietary intakes relative to more objective urine measures among participants receiving lifestyle interventions. METHODS We analyzed longitudinal data from 900 individuals with hypertension who had been enrolled in a randomized controlled clinical trial to establish whether usual care or three lifestyle interventions (weight loss, sodium reduction, and combined weight loss and sodium reduction) could effectively substitute for phamacotherapy. Repeated standardized 24-hour diet recalls and 24-hour urine collections were collected over up to three years of follow-up to estimate sodium and potassium intakes. By contrasting self-reported and urine-based sodium and potassium data collected before and during interventions, we examined the relative impact of intervention assignment on estimated intakes, repeatability, and multivariate measurement error. RESULTS Relative to urine-based measures, mean self-reported sodium intakes were biased about 10% lower among participants assigned to combined weight loss and sodium reduction, but were unaffected by the other interventions. The repeatability of self-report measures increased slightly with time, particularly among participants assigned to sodium interventions. Errors in self-reported sodium and potassium intakes were correlated before the start of the intervention, but became uncorrelated among individuals assigned to sodium restriction interventions. CONCLUSIONS Lifestyle interventions may influence not only diet intake, but also the measurement of diet intake.

Acyl chain length, saturation, and hydrophobicity modulate the efficiency of dietary fatty acid absorption in adult humans

Intestinal fat absorption is known to be, overall, a highly efficient process, but much less is known about the efficiency with which individual dietary fatty acids (FA) are absorbed by the adult small intestine. We therefore measured the absorption efficiency of the major dietary FA using sucrose polybehenate (SPB) as a nonabsorbable marker and analyzed how it is modulated by acyl chain physicochemical properties and polymorphisms of proteins involved in chylomicron assembly. Dietary FA absorption efficiency was measured in 44 healthy subjects fed a standard diet containing 35% fat and 5% SPB. FA and behenic acid (BA) were measured in homogenized diets and stool samples by gas chromatography-mass spectroscopy, and coefficients of absorption for each FA were calculated as 1 - [(FA/BA)feces/(FA/BA)diet]. Absorption coefficients for saturated FA decreased with increasing chain length and hydrophobicity (mean ± SE) and ranged from 0.95 ± 0.02 for myristate (14:0), 0.80 ± 0.03 for stearate (18:0), to 0.26 ± 0.02 for arachidate (20:0). Absorption coefficients for unsaturated FA increased with increasing desaturation from 0.79 ± 0.03 for elaidic acid (18:1t), 0.96 ± 0.01 for linoleate (18:2), to near complete absorption for eicosapentaenoic (20:5) and docosahexaenoic (22:6) acids. Of several common genetic polymorphisms in key proteins involved in the chylomicron assembly pathway, only the intestinal fatty acid-binding protein-2 A54T allele (rs1799883) had any impact on FA absorption. We conclude that acyl chain length, saturation, and hydrophobicity are the major determinants of the efficiency with which dietary FA are absorbed by the adult small intestine.

The Impact of Dietary Calcium and Oxalate Ratios on Stone Risk

OBJECTIVE To determine whether the ratio of dietary calcium and oxalate consumption at mealtime affects gastrointestinal oxalate absorption and urinary oxalate excretion. METHODS A study was conducted with 10 non-stone-forming adults placed on controlled diets with daily calcium and oxalate contents of 1000 and 750 mg, respectively. Subjects consumed a balanced calcium/oxalate ratio diet for 1 week, observed a minimum 1-week washout period, and subsequently consumed an imbalanced calcium/oxalate ratio diet for one week. Urine specimens were collected on the last 4 days of each diet. Outcome measures included urinary creatinine, calcium, and oxalate as well as the Tiselius index for assessing urinary calcium oxalate supersaturation. RESULTS Total daily calcium excretion, oxalate excretion, and Tiselius index were similar between balanced and imbalanced dietary phases. There were significant differences in calcium excretion (mg/g creatinine) between balanced and imbalanced diets in the 1-6 PM (83.1 vs 110.2, P <.04), 6-11 PM (71.3 vs 107.2, P <.02), and 11 PM-8 AM collections (55.0 vs 41.8, P <.02). There was significantly higher oxalate excretion on the balanced diet in the 1-6 pm time period (28.1 vs 16.7, P <.01). There were no differences in the Tiselius index in these collections. CONCLUSION These results demonstrate that the sequence of ingesting relatively large amounts of oxalate does not significantly affect calcium oxalate stone risk if the recommended daily quantity of dietary calcium is consumed.

Tissue-Specific and Genetic Regulation of Insulin Sensitivity-Associated Transcripts in African Americans

Integrative multiomics analyses of adipose and muscle tissue transcripts, S, and genotypes revealed novel genetic regulatory mechanisms of insulin resistance in African Americans.

A Double-Blind, Placebo Controlled, Randomized Phase 1 Cross-Over Study with ALLN-177, an Orally Administered Oxalate Degrading Enzyme

Background: Hyperoxaluria may result from increased endogenous production or overabsorption of dietary oxalate in the gastrointestinal tract leading to nephrolithiasis and, in some, to oxalate nephropathy and chronic kidney disease. ALLN-177 is an oral formulation of a recombinant, oxalate specific, microbial enzyme oxalate decarboxylase intended to treat secondary hyperoxaluria by degrading dietary oxalate in the gastrointestinal tract, thereby reducing its absorption and subsequent excretion in the urine. Methods: This double-blind, placebo controlled, randomized, cross-over, phase 1 study of ALLN-177 evaluated the tolerability of ALLN-177 and its effect on urinary oxalate excretion in 30 healthy volunteers with hyperoxaluria induced by ingestion of a high oxalate, low calcium (HOLC) diet. The primary end point was the difference in the mean 24-hour urinary oxalate excretion during the ALLN-177 treatment period compared with the placebo treatment period. Results: The daily urinary oxalate excretion increased in the study population from 27.2 ± 9.5 mg/day during screening to 80.8 ± 24.1 mg/day (mean ± SD) on the HOLC diet before introducing ALLN-177 or placebo therapy for 7 days. Compared to placebo, ALLN-177 treatment reduced urinary oxalate by 11.6 ± 2.7 mg/day, p = 0.0002 (least squares mean ± SD). Conclusions: In healthy volunteers, with diet-induced hyperoxaluria treatment with ALLN-177, when compared to placebo, significantly reduced urinary oxalate excretion by degrading dietary oxalate in the gastrointestinal tract and thereby reducing its absorption. ALLN-177 may represent a new approach for managing secondary hyperoxaluria and its complications.