Effect of protein source during weight loss on body composition, cardiometabolic risk and physical performance in abdominally obese, older adults: a pilot feeding study

OBJECTIVES

The purpose of this pilot study was to begin to examine the effect of dietary protein source (soy protein versus non-soy protein) during weight loss on body composition, and cardiometabolic and functional decline risk factors in older, abdominally obese adults.

DESIGN

Two-arm, single-blind, randomized, controlled trial.

SETTING

Wake Forest School of Medicine, Winston-Salem NC 27157, USA.

PARTICIPANTS

25 older (68.4±5.5 years, 88% female), abdominally obese (BMI: 35.1±4.3 kg/m2; WC: 101.4±13.1 cm) men and women were randomized to participate in the study.

INTERVENTION

A 12-week weight loss intervention, with participants randomized to consume soy protein-based meal replacements (S; n=12) or non-soy protein-based meal replacements (NS; n=12), in addition to prepared meals, and all participants targeted to receive an individualized caloric deficit of 500 kcal/day.

MEASUREMENTS

Body weight and composition (assessed via DXA and CT), conventional biomarkers of cardiometabolic risk, and physical performance measures were assessed pre- and post-intervention. Additional endpoints of feasibility (accrual, participation, retention, compliance, and safety) are reported.

RESULTS

A total of 24 participants (87% female) completed the study (96% retention) and lost an average of 7.8±3.0 kg over the 12-week period, with no difference seen between groups (p=0.83). Although nearly all measures of global and regional body composition were significantly reduced following the 12-week intervention, differences were not observed between groups. Among cardiometabolic risk factors and physical performance measures, only diastolic blood pressure was significantly lower in the NS group compared to the S group (66.7±2.7 mmHg vs 73.5±2.7 mmHg, respectively; p=0.04). Interestingly, in groups combined, despite significant reductions in body weight and lean mass, no significant changes in 400-meter walk time (+5.3±43.4 s), short physical performance battery score (+0.1±1.0), grip strength (-0.3±3.2 kg), or relative knee extensor strength (-0.0±0.0 N/m/cm3 thigh muscle volume) were observed.

CONCLUSIONS

Data presented here suggest that a 12-week weight loss intervention, which incorporates S and NS meal replacement products, is associated with clinically significant weight loss and improvements in several parameters of cardiometabolic risk and unchanged physical function and strength. RESULTS do not differ by protein source and suggest that soy protein is at least as good as other protein sources for weight loss during low-calorie dietary interventions in older adults.

Generalization of adiposity genetic loci to US Hispanic women

BACKGROUND:

Obesity is a public health concern. Yet the identification of adiposity-related genetic variants among United States (US) Hispanics, which is the largest US minority group, remains largely unknown.

OBJECTIVE:

To interrogate an a priori list of 47 (32 overall body mass and 15 central adiposity) index single-nucleotide polymorphisms (SNPs) previously studied in individuals of European descent among 3494 US Hispanic women in the Women's Health Initiative SNP Health Association Resource (WHI SHARe).

DESIGN:

Cross-sectional analysis of measured body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) were inverse normally transformed after adjusting for age, smoking, center and global ancestry. WC and WHR models were also adjusted for BMI. Genotyping was performed using the Affymetrix 6.0 array. In the absence of an a priori selected SNP, a proxy was selected (r²⩾0.8 in CEU).

RESULTS:

Six BMI loci (TMEM18, NUDT3/HMGA1, FAIM2, FTO, MC4R and KCTD15) and two WC/WHR loci (VEGFA and ITPR2-SSPN) were nominally significant (P<0.05) at the index or proxy SNP in the corresponding BMI and WC/WHR models. To account for distinct linkage disequilibrium patterns in Hispanics and further assess generalization of genetic effects at each locus, we interrogated the evidence for association at the 47 surrounding loci within 1 Mb region of the index or proxy SNP. Three additional BMI loci (FANCL, TFAP2B and ETV5) and five WC/WHR loci (DNM3-PIGC, GRB14, ADAMTS9, LY86 and MSRA) displayed Bonferroni-corrected significant associations with BMI and WC/WHR. Conditional analyses of each index SNP (or its proxy) and the most significant SNP within the 1 Mb region supported the possible presence of index-independent signals at each of these eight loci as well as at KCTD15.

CONCLUSION:

This study provides evidence for the generalization of nine BMI and seven central adiposity loci in Hispanic women. This study expands the current knowledge of common adiposity-related genetic loci to Hispanic women.

Health risks and benefits from calcium and vitamin D supplementation: Women's Health Initiative clinical trial and cohort study

SUMMARY

The Women's Health Initiative (WHI) double-blind, placebo-controlled clinical trial randomly assigned 36,282 postmenopausal women in the U.S. to 1,000 mg elemental calcium carbonate plus 400 IU of vitamin D(3) daily or placebo, with average intervention period of 7.0 years. The trial was designed to test whether calcium plus vitamin D supplementation in a population in which the use of these supplements was widespread would reduce hip fracture, and secondarily, total fracture and colorectal cancer.

INTRODUCTION

This study further examines the health benefits and risks of calcium and vitamin D supplementation using WHI data, with emphasis on fractures, cardiovascular disease, cancer, and total mortality.

METHODS

WHI calcium and vitamin D randomized clinical trial (CT) data through the end of the intervention period were further analyzed with emphasis on treatment effects in relation to duration of supplementation, and these data were contrasted and combined with corresponding data from the WHI prospective observational study (OS).

RESULTS

Among women not taking personal calcium or vitamin D supplements at baseline, the hazard ratio [HR] for hip fracture occurrence in the CT following 5 or more years of calcium and vitamin D supplementation versus placebo was 0.62 (95 % confidence interval (CI), 0.38-1.00). In combined analyses of CT and OS data, the corresponding HR was 0.65 (95 % CI, 0.44-0.98). Supplementation effects were not apparent on the risks of myocardial infarction, coronary heart disease, total heart disease, stroke, overall cardiovascular disease, colorectal cancer, or total mortality, while evidence for a reduction in breast cancer risk and total invasive cancer risk among calcium plus vitamin D users was only suggestive.

CONCLUSION

Though based primarily on a subset analysis, long-term use of calcium and vitamin D appears to confer a reduction that may be substantial in the risk of hip fracture among postmenopausal women. Other health benefits and risks of supplementation at doses considered, including an elevation in urinary tract stone formation, appear to be modest and approximately balanced.

Soy protein isoflavones, lipids and arterial disease

There is convincing evidence that soybean products have beneficial effects on cardiovascular disease risk factors. Interest in understanding which components of the soybean are responsible for the potential benefits on cardiovascular disease risk factors and the magnitude of their effect continues. This review focuses on the scientific literature published during 1999-2001, evaluating the effects of soy protein isolate, soy foods, and purified isoflavones on plasma lipid concentrations and other cardiovascular disease outcomes.

Vitamin and mineral supplement use by older rural adults

BACKGROUND

Vitamin and mineral supplement products are widely consumed by older adults. This study describes supplement product use in a multiethnic rural population, relates supplement usage to dietary nutrient intake, and determines predictors of supplement usage.

METHODS

Data are from a population-based sample of 130 community-dwelling adults aged 70 years and older in two rural North Carolina counties. The sample was 34% African American, 36% European American, and 30% Native American. Interviewer-administered semiquantitative food frequency questionnaires were used to obtain data on usual diet and supplement use. In-home interviews allowed verification of supplement composition. Intakes from diet and supplement products were examined for vitamins A, E, B6, C, folate, iron, zinc, and calcium.

RESULTS

Of those who participated in the study, 47% reported using one or more supplement products. African Americans were significantly less likely to take supplements than Native Americans or European Americans. Based on dietary intakes, 65% of the participants were deficient (<2/3 recommended dietary allowance [RDA]) for at least one nutrient. The use of supplement products for the eight nutrients investigated was not related to dietary nutrient deficiency. For all nutrients investigated, except iron and calcium, a greater proportion of those without dietary deficiency took a supplement product than those with deficiency. Using logistic regression, ethnicity (European American and Native American), and gender (women) were significant predictors of supplement use.

CONCLUSIONS

These findings suggest that although both dietary deficiencies of vitamins and minerals and supplement use are relatively high in this population, there is no association between supplement use and deficient dietary intakes for the eight nutrients examined. Health care providers should be aware that nutritional counseling and guidance on appropriate supplement usage is needed in this population.

Measuring adherence to behavioral and medical interventions

Measuring adherence to medical and behavioral interventions is important to clinicians and researchers since inadequate adherence can reduce the effectiveness of an intervention. Unfortunately, there is no gold standard for measuring adherence across health behaviors. Adherence needs to be defined situationally with parameters of acceptable adherence carefully delineated and appropriate to the health behavior being studied. Additionally, measurement methods must be valid, reliable, and sensitive to change; this paper reviews these criteria. Methods used to measure adherence to dietary interventions include 24-hour recalls, food diaries, and food frequency questionnaires. Direct and indirect calorimetry, doubly labeled water, and a variety of self-report methods can be used to measure adherence in physical activity interventions. Adherence to pharmacological interventions is assessed using self-report methods, biochemical measures, medication counts, and the automated pharmacy database review strategy. The strengths and weaknesses of these methods for measuring adherence to dietary, physical activity, and pharmacological interventions are reviewed. Control Clin Trials 2000;21:188S-194S

On their own: nutritional self-management strategies of rural widowers

In-depth interviews conducted with 12 rural widowers participating in a population-based study of nutritional strategies of rural adults 70 years and older were analyzed to (a) identify factors that place widowers at risk for nutritional problems and (b) understand how rural residence is related to this risk. The nutritional strategies that successfully accomplished three groups of food-related tasks (food acquisition, food use, and maintaining food security) focused on one of three resource domains: self-care, informal support, and formal support. Resources that facilitated these nutritional strategies are identified, as are those conditions that led to nutritional strategies inadequate to ensure food acquisition, food use, and food security. These findings can be used to help identify rural elderly widowers who are at nutritional risk.

Nutritional self-management of elderly widows in rural communities

Studies of the nutritional status of older adults (by marital status) and of older women recently widowed suggest that widows are nutritionally vulnerable. Yet few studies have examined nutrition-related behaviors among widows to see why this is true. We conceptualize these behaviors as nutritional self-management strategies, encompassing behaviors related to obtaining food, consuming it, and maintaining food security. Data come from in-depth interviews conducted with 64 widowed women age 70+ in rural North Carolina (23 African American, 24 European American, 17 Native American). Transcripts were coded and analyzed using a systematic text-analysis procedure. Length of widowhood ranged from less than 1 year to 39 years. Themes identified in recent widows' interviews and corroborated in those widowed longer indicate that there are varied responses to widowhood. Some may have a positive impact on nutritional strategies (e.g., following own dietary needs), but most are likely to be negative (e.g., meal skipping, reduced home food production, less dietary variety). Rural communities need to develop ways to identify such widows and assist them in finding acceptable ways to meet nutritional needs.

Use of the Pelvic Organ Prolapse staging system of the International Continence Society, American Urogynecologic Society, and Society of Gynecologic Surgeons in perimenopausal women

OBJECTIVES

This study was undertaken to apply the standardized Pelvic Organ Prolapse staging system to perimenopausal women to obtain normative data and to determine any effects of risk factors for incontinence and prolapse on Pelvic Organ Prolapse staging system scores.

STUDY DESIGN

Two hundred forty-one women aged 45 to 55 years who were seen for perimenopausal care were evaluated in the dorsal lithotomy position for pelvic prolapse at enrollment and again at 12 months. Prolapse was scored according to the Pelvic Organ Prolapse staging system, as approved by the International Continence Society. All subjects completed questionnaires to obtain demographic data, reproductive history, and gynecologic history. Data were evaluated with the Mann-Whitney rank sum test and with 1-way analysis of variance on ranks.

RESULTS

The subjects had a mean parity of 2.2 and a mean weight of 72.4 kg. Hysterectomy had been performed in 28% of the women. Urinary incontinence was reported by 66% of the women at enrollment. Mean prolapse scores that described the position of the cervix, the position of the posterior fornix, and the total vaginal length were significantly changed by the 1-year follow-up, with scores reflecting increased prolapse. The mean score at point Ba, which represents the proximal portion of the anterior vaginal wall, was significantly lower, consistent with decreased prolapse at this site. History of smoking, prior hysterectomy, weight, parity, and incontinence at enrollment did not significantly correlate with any of the 9 measured prolapse points.

CONCLUSIONS

Normative data for the Pelvic Organ Prolapse staging system of the International Continence Society, American Urogynecologic Society, and Society of Gynecologic Surgeons were measured in a group of perimenopausal women. Apparent increases in prolapse at points C, D, and tvl may reflect changes in vaginal size rather an increase in uterine or vaginal vault prolapse. This variability may confound the use of the Pelvic Organ Prolapse staging system in longitudinal studies involving perimenopausal women.

Validity and reproducibility of a food frequency interview in a Multi-Cultural Epidemiology Study

PURPOSE

There is limited support for the validity and reproducibility of dietary assessment in culturally diverse populations. The goal of this study was to evaluate the comparative validity and reproducibility of a Food Frequency Questionnaire (FFQ) used in the observational, multi-cultural Insulin Resistance Atherosclerosis Study (IRAS).

METHODS

Women (n = 186) were approximately equally distributed by ethnicity from one urban center (African Americans and non-Hispanic whites) and one rural center (Hispanics and non-Hispanic whites). The IRAS FFQ was modified from the National Cancer Institute Health Habits and History Questionnaire to include ethnic and regional foods. Validity was assessed by comparing dietary values, including supplements, obtained from the FFQ to the average intake estimated from a series of 8 24-hour dietary recalls collected by telephone over the same 1-year period. Reproducibility was assessed among women who reported no change in their usual diet (n = 133) by comparing data from the original IRAS FFQ (in-person) with the FFQ administered for the validity study (two to four years later, by telephone).

RESULTS

Correlation coefficients for validity were statistically significant for most nutrients (mean r = 0.62 urban non-Hispanic white, 0.61 rural non-Hispanic whites, 0.50 African American, 0.41 Hispanic) and did not differ among subgroups of obesity or diabetes status. The median correlation coefficient for the total sample was 0.49. Correlations were lower for women with less than 12 years of education (mean r = 0.30; median r = 0.25). The lower correlations among Hispanics was largely explained by the lower educational attainment in that sample. For reproducibility, the mean correlation for nutrients evaluated was r = 0.62 (median r = 0.63) and did not differ for subgroups.

CONCLUSIONS

Although educational attainment must be considered, the IRAS FFQ appears to be reasonably valid and reliable in a diverse cohort.

Barriers to nutritional well-being for rural elders: community experts' perceptions

Older adults use public and private services, as well as personal resources, to meet nutritional needs. In-depth interviews conducted with 73 service providers and community experts in two rural North Carolina counties were analyzed for these experts' perceptions of barriers to adequate nutrition for older adults. Perceived barriers included characteristics of the county and programs, transportation, and kin, as well as older adult medical and economic conditions, food habits, knowledge, and attitudes. The importance given each of these domains varied by respondents' area of expertise. Community experts and providers may not see the connection between their services and nutritional well-being of older adults.

Dietary fat and insulin sensitivity in a triethnic population: the role of obesity. The Insulin Resistance Atherosclerosis Study (IRAS)

From the Insulin Resistance Atherosclerosis Study (IRAS), 1173 men and women of African-American, non-Hispanic white, and Hispanic ethnicity with no history of diabetes were included in an evaluation of the cross-sectional relation of habitual dietary fat intake with insulin sensitivity (SI) as assessed by minimal-model analysis of a 12-sample, insulin-modified frequently sampled intravenous-glucose-tolerance test. Dietary intake was measured by a food-frequency interview modified to enhance sensitivity to food choices within the three ethnic groups. Percentage of energy from total fat was associated with rank of SI (SI(rank); r = -0.06, P = 0.03), with log fasting insulin (r = 0.10, P < 0.001), and with BMI (r = 0.10, P < 0.001). Multiple-linear-regression models included SI(rank) as the dependent variable, dietary fat (g/d) as the primary independent variable adjusted sequentially for total energy, other covariates, body mass index, and waist-hip circumference ratio (WHR). For all subjects combined, total fat intake was inversely related to SI(rank), but this association was not significant (P = 0.14) and was attenuated by adjustment for body mass index and WHR (P = 0.44). The association of total fat (g/d) with SI(rank) differed significantly (P < 0.01) for obese compared with nonobese individuals. Higher fat intake was associated with lower SI(rank) among obese (beta = -1.40, P = 0.03) but not among nonobese persons (beta = 0.16, P = 0.80). Among the obese (body mass index < or = 63), adjustment for body mass index largely accounted for the observed association of dietary fat with SI(rank). These findings were generally consistent for monounsaturated, polyunsaturated, and saturated fats. Among individuals already at increased risk for non-insulin-dependent diabetes mellitus because of obesity, high intake of dietary fat may worsen insulin sensitivity. This effect may be mediated by the relation of dietary fat to obesity.