Rhonda A. Brownbill

Bone and nutrition in elderly women: protein, energy, and calcium as main determinants of bone mineral density

Objective: Nutrition is an important factor in the prevention and treatment of osteoporosis. Our goal was to examine the relationship between various nutrients and bone mass of several skeletal sites in elderly women, taking into account possible confounding variables.Design/methods: A cross-sectional study in 136 healthy Caucasian, postmenopausal women, free of medications known to affect bone was carried out. Bone mineral density (BMD) and body composition (lean and fat tissue) were measured by dual X-ray absorptiometry using specialized software for different skeletal sites. Parathyroid hormone (PTH) and vitamin D, 25(OH)D, as possible confounders, were determined in serum samples. Dietary intake, including all supplements, was assessed by 3-day dietary record and analyzed using Food Processor®. Past physical activity and present walking were examined as well and accounted for as potential confounders. Simple and multiple regression models were created to assess the relationships between nutrients and BMD. To examine the co-linear variables and their possible independent association with bone, subgroup analyses were performed.Results: Showed independent influence of calcium, energy, and protein, examined separately and in multiple regression models on BMD of several skeletal sites. Magnesium, zinc and vitamin C were significantly related to BMD of several skeletal sites in multiple regression models (controlled for age, fat and lean tissue, physical activity and energy intake), each contributing more than 1% of variance. Serum PTH and 25(OH)D did not show significant association with bone mass.Conclusions: Despite the cross-sectional nature of our study we were able to show a significant relationship between BMD and several critical nutrients: energy, protein, calcium, magnesium, zinc and vitamin C. The exact involvement of these nutrients and their clinical significance in bone health need to be further elucidated in humans and conclusions about the effects of a single nutrient on bone mass must be given cautiously, taking into account its interaction and co-linearity with others. Understanding relationships among nutrients, not just limited to calcium and vitamin D, but others that have not been investigated to such extent, is an important step toward identifying preventive measures for bone loss and prevention of osteoporosis.

To drink or not to drink:How are alcohol, caffeine and past smoking related to bone mineral density in elderly women.

Objectives: To determine relationship between alcohol, caffeine, past smoking and bone mineral density of different skeletal sites in elderly women, accounting for other biological and life-style variables. Methods/Design: A cross-sectional study in 136 Caucasian women, mean ± SD age 68.6 ± 7.1 years, all healthy and free of medications affecting bones, including estrogen. Bone mineral density (BMD) of multiple skeletal regions and body composition were measured by dual X-ray absorptiometry. Serum vitamin D (25-OHD) and parathyroid hormone (PTH) were analyzed and used as confounders. Calcium (Ca) intake was assessed by food frequency questionnaire. Alcohol and caffeine consumption was assessed by questionnaires determining frequency, amount and source of each. There were no current smokers, but the history of smoking was recorded, including number of years and packages smoked/day. Past physical activity was assessed by Allied Dunbar National Fitness Survey and used as confounder. Statistical significance was considered at p ≤ 0.05. Results: In the correlational analysis, alcohol was positively associated with spine BMD (r = 0.197, p = 0.02), 25-OHD and negatively with PTH. Smoking was negatively related to Ca intake, 25(OH)D and number of reproductive years. In subgroup (stratified by Ca intake) and multiple regression analyses, alcohol (average ∼0.5–1 drinks/day or ∼8 g alcohol/day) was favorably associated with BMD of spine and total body. Caffeine (average ∼2.5 6-fl oz cups/day or 200–300 mg caffeine/day) had negative association with most of the skeletal sites, which was attenuated with higher Ca intake (≥median, 750 mg/day). The past smokers who smoked on average 24 years of ∼1 pack cigarettes/day had lower BMD in total body, spine and femur than never-smokers when evaluated in subgroup analyses, and the association was attenuated in participants with ≥median Ca intake. There was no significant association between past smoking and BMD of any skeletal site in multiple regression analyses. Conclusion: The results support the notion that consumption of small/moderate amount of alcohol is positively, while caffeine and past smoking are negatively associated with most of the skeletal sites, which might be attenuated with Ca intake above 750 mg/day.

Association between dietary conjugated linoleic acid and bone mineral density in postmenopausal women

Objective: To determine if dietary conjugated linoleic acid (CLA) is associated with bone mineral density (BMD) of different skeletal sites in postmenopausal women. Methods: A cross-sectional analysis in 136 Caucasian, healthy, postmenopausal women, mean age 68.6 years. BMD and soft tissue were assessed by dual energy x-ray abosorptiometry (DXA). Energy, calcium, protein, fat, CLA and other relevant nutrients were estimated using 3 day dietary records. Supplement use was recorded as well. Current and past physical activity were determined using the Allied Dunbar National Fitness Survey for older adults. Results: CLA (63.1 ± 46.8 mg, mean ± SD) was a significant predictor of Ward’s triangle BMD (p = 0.040) in a multiple regression model containing years since menopause (18.5 ± 8.4 y), lean tissue, energy intake (1691 ± 382 kcal/day) dietary calcium (873 ± 365 mg), protein (70.6 ± 18.6 g), fat (57.9 ± 23.9 g), zinc (19.2 ± 13.6 mg), and current and past physical activity, with R2adj = 0.286. Subjects were also divided into groups below (Group 1) and above (Group 2) the median intake for CLA. Group 2 had higher BMD in the forearm, p = 0.042, and higher BMD in the hip, lumbar spine and whole body, however statistical significance was not reached. Conclusion: These findings indicate dietary CLA may positively benefit BMD in postmenopausal women. More studies are warranted examining the relationship between dietary CLA and BMD.

Weight Loss Favorably Modifies Anthropometrics and Reverses the Metabolic Syndrome in Premenopausal Women

Objective: To determine the effects of a weight loss program, including dietary modifications, increased physical activity and dietary supplement (L-carnitine or placebo) on anthropometrics, leptin, insulin, the metabolic syndrome (MS) and insulin resistance in overweight /obese premenopausal women. Methods: Participants consumed a hypocaloric diet; 30% protein, 30% fat and 40% carbohydrate in addition to increasing number of steps/day. Carnitine supplementation followed a randomized double blind protocol. Protocol lasted for 10 weeks. Seventy subjects (35 in the control and 35 in the carnitine group) completed the intervention. Anthropometrics, plasma insulin and leptin concentrations and body composition were measured. The number of subjects with the MetSyn and insulin resistance, were assessed at baseline and post-intervention. Results: Because there were no significant differences between the carnitine and the placebo groups for all measured parameters, participants were grouped together for all analysis. Subjects decreased total energy (−26.6%, p < 0.01) and energy from carbohydrate (−17.3%, p < 0.01) and increased energy from protein by 67% (p < 0.01) and number of steps/day (42.6%, p < 0.01). Body weight (−4.6%, p < 0.001), body mass index (−4.5%, p < 0.01), waist circumference (−6.5%, p < 0.01), total fat mass (−1.7%, p < 0.01), trunk fat mass (−2.0%, p < 0.01), insulin (− 17.9%, p < 0.01) and leptin (−5.9%, p < 0.05) decreased after the intervention. Ten of 19 participants with insulin resistance became insulin sensitive and 7 of 8 participants with the MetSyn no longer had the syndrome after the intervention. Conclusion: Moderate increases in physical activity and a hypocaloric/high protein diet resulted in multiple beneficial effects on body anthropometrics and insulin sensitivity. Realistic dietary and physical activity goals must be the focus of intervention strategies for overweight and obese individuals.

Measuring body composition in overweight individuals by dual energy x-ray absorptiometry

BackgroundDual energy x-ray absorptiometry (DXA) is widely used for body composition measurements in normal-weight and overweight/obese individuals. The limitations of bone densitometers have been frequently addressed. However, the possible errors in assessing body composition in overweight individuals due to incorrect positioning or limitations of DXA to accurately assess both bone mineral density and body composition in obese individuals have not received much attention and are the focus of this report.DiscussionWe discuss proper ways of measuring overweight individuals and point to some studies where that might not have been the case. It appears that currently, the most prudent approach to assess body composition of large individuals who cannot fit under the scanning area would be to estimate regional fat, namely the regions of thigh and/or abdomen. Additionally, using two-half body scans, although time consuming, may provide a relatively accurate measurement of total body fat, however, more studies using this technique are needed to validate it.SummaryResearchers using bone densitometers for body composition measurements need to have an understanding of its limitations in overweight individuals and address them appropriately when interpreting their results. Studies on accuracy and precision in measurements of both bone and soft tissue composition in overweight individuals using available densitometers are needed.

Dual Hip Bone Mineral Density in Postmenopausal Women: Geometry and Effect of Physical Activity

The objectives of this study were to (1) obtain both femoral neck strength (FNS) and hip axis length (HAL) values from left and right femurs (regardless of hip dominance) measured by DXA and evaluate their relationship with BMD of all hip regions including total hip, (2) determine if there is a difference between dominant and nondominant hip BMD in any of the hip regions, and (3) determine how physical activity influences hip BMD. Participants were 136, generally healthy Caucasian women (57.4–88.6 years). BMD was measured by DPX-MD. Past and present activity was assessed by the Allied Dunbar National Fitness Survey for older adults and normal/brisk walking pace was measured in a straight hallway. FNS analysis uses femoral geometry to calculate stresses at the femoral neck for two loading conditions: Safety Factor Index (SF) indicates risk of fracture for forces generated during a one-legged stance, and Fall Index (FI) indicates risk of fracture for forces generated during a fall on the greater trochanter. Simple and multiple regression analyses were used to determine predictive ability of HAL, SF, and FI for respective hip BMD values. There was no statistical difference in BMD between two hips in any of the measured regions, however, the nondominant hip correlated better with other skeletal sites. Subjects with a faster normal walking speed had higher neck BMD in the nondominant hip, 0.832 ± 0.12 vs. 0.791 ± 0.10 g/cm2 (P < 0.05). Longer HAL of the left hip was negatively related to neck, trochanter, shaft, and total hip BMD. FI was significantly associated with all sites of the hip BMD, while SF was associated only with neck and wards BMC (P < 0.05). In summary: (1) a longer HAL is associated with lower BMD and a higher FI with higher BMD, (2) it might be sufficient to measure BMD in only the nondominant hip, and (3) walking at a faster pace may positively benefit femoral neck BMD. Therefore, it appears that HAL, SF, and FI all play important roles in estimating fracture risk and should be assessed along with BMD when using DXA.

Nutrition Through the Life Span: Needs and Health Concerns in Critical Periods

The focus of this chapter is to discuss the nutritional requirements of individuals in different periods of life, spanning from infancy and childhood to old age. We start with the pregnancy and maternal nutritional needs, which ultimately determine fetal growth and development. We continue by addressing the main issues in infancy, childhood, and adolescence, focusing on the critical nutrients in each period, dietary patterns and behaviors, and most common disorders associated with food intake in those periods. Adult period focuses on the balanced nutrition and lifestyle conducive to disease prevention and maintenance of healthy state. The section on older adults addresses some of the most critical nutrients for that period, as well as some chronic conditions and the ways to avoid or alleviate them.

Impact of Nutritional Knowledge on Food Choices and Dietary Intake of College Students

Abstract The main factors influencing dietary habits and nutritional intakes of college students remain unclear. Our hypothesis was that students enrolled in dietetic and/or nutritional programs would have dietary intake closer to current nutritional recommendations (DRIs or RDAs) compared to the students without nutritional background. The study included 122 students (mean±SD age 24.4±5.4 years) of whom 44 (36%) were students in dietetics and/or nutritional sciences programs (NUTR) and 78 (64%) had no formal nutritional education (N-NUTR). The participants completed 3-day dietary records. All were instructed on how to complete dietary records and shown food models. The records were analyzed using Nutritionist® program for all nutrients, including supplements. The nutrients for females and males were analyzed separately and comparison was done between female NUTR and N-NUTR and male NUTR and N-NUTR by t-test, p