Marta Van Loan | University of California, Davis (original) (raw)

Papers by Marta Van Loan

Dietary fat and not calcium supplementation or dairy product consumption is associated with chang... more Dietary fat and not calcium supplementation or dairy product consumption is associated with changes in anthropometrics during a randomized, placebo-controlled energy-restriction trial

Current Developments in Nutrition, 2019

Objectives The glucostatic theory of appetite suggests that changes in blood glucose determine hu... more Objectives The glucostatic theory of appetite suggests that changes in blood glucose determine hunger and food intake behavior. While, this is the most popular theory to date it is not without controversy. Our goal was to evaluate this theory in an acute buffet meal challenge setting. Methods Overweight and obese (BMI: 32.9 ± 2.6 kg/m2) men and women (n = 21 and 50 respectively) were tested in a daylong satiety protocol. After an overnight fast, blood draws and self-reported visual analog scores for appetite questions were obtained at the following times: 2 times at fasting, 5 times after a breakfast meal providing 25% of energy need, and 12 times after a lunch meal with 40% of energy need 4 h after breakfast. Satiety hormones (plasma insulin, ghrelin, amylin, PYY, CCK, GIP and GLP-1) and plasma glucose and triglycerides were measured. A buffet dinner was offered beginning 4 h after lunch and participants self-selected the time and duration for this meal. The inter-meal interval bet...

Test meal ingredient list. (DOCX 14Â kb)

Nutrients, 2021

Background: Time restricted Feeding (TRF) is a dietary pattern utilized by endurance athletes, bu... more Background: Time restricted Feeding (TRF) is a dietary pattern utilized by endurance athletes, but there is insufficient data regarding its effects on performance and metabolism in this population. The purpose of this investigation was to examine the effects of a 16/8 TRF dietary pattern on exercise performance in trained male endurance runners. Methods: A 4-week randomized crossover intervention was used to compare an 8-h TRF to a 12-h normal diet (ND) feeding window. Exercise training and dietary intake were similar across interventions. Runners completed a dual-energy X-ray absorptiometry (DXA) scan to assess body composition, a graded treadmill running test to assess substrate utilization, and ran a 10 km time trial to assess performance. Results: There was a significant decrease in fat mass in the TRF intervention (−0.8 ± 1.3 kg with TRF (p = 0.05), vs. +0.1 ± 4.3 kg with ND), with no significant change in fat-free mass. Exercise carbon dioxide production (VCO2) and blood lacta...

The Journal of Nutrition, 2021

Background A variety of modifiable and nonmodifiable factors such as ethnicity, age, and diet hav... more Background A variety of modifiable and nonmodifiable factors such as ethnicity, age, and diet have been shown to influence bone health. Previous studies are usually limited to analyses focused on the association of a few a priori variables or on a specific subset of the population. Objective Dietary, physiological, and lifestyle data were used to identify directly modifiable and nonmodifiable variables predictive of bone mineral content (BMC) and bone mineral density (BMD) in healthy US men and women using machine-learning models. Methods Ridge, lasso, elastic net, and random forest models were used to predict whole-body, femoral neck, and spine BMC and BMD in healthy US men and women ages 18–66 y, with a BMI (kg/m2) of 18–44 (n = 313), using nonmodifiable anthropometric, physiological, and demographic variables; directly modifiable lifestyle (physical activity, tobacco use) and dietary (via FFQ) variables; and variables approximating directly modifiable behavior (circulating 25-hyd...

Current Developments in Nutrition, 2021

Objectives A variety of modifiable and non-modifiable factors such as ethnicity, age, and diet ha... more Objectives A variety of modifiable and non-modifiable factors such as ethnicity, age, and diet have been shown to influence bone health. Previous studies are usually limited to analyses focused on the association of a few a priori variables or on a specific subset of the population. The objective of this study was to use dietary, physiological, and lifestyle data to identify directly modifiable and non-modifiable variables predictive of bone mineral content (BMC) and bone mineral density (BMD) in healthy US men and women using machine learning models. Methods Ridge, lasso, elastic net, and random forest models were used to predict whole-body, femoral neck, and spine BMC and BMD in healthy US adults (n = 313) using non-modifiable anthropometric, physiological, and demographic variables, directly modifiable lifestyle (physical activity, tobacco use) and dietary (nutrient or food groups intake via food frequency questionnaire) variables, and variables approximating directly modifiable ...

Medical Research Archives, 2015

The American journal of clinical nutrition, 2003

An average daily calcium intake of 1300 mg is recommended for North American adolescents aged 9-1... more An average daily calcium intake of 1300 mg is recommended for North American adolescents aged 9-18 y. However, questions remain about these recommendations. We assessed whether there is a stage of puberty when dietary calcium is more strongly related to peak bone mass, as indicated by young adult bone mass (YABM); whether dietary calcium intake > 1000 mg/d in adolescence is associated with higher YABM; and whether race affects any of these associations between dietary calcium and YABM. Secondarily, we evaluated relations between sedentariness and YABM. In a retrospective cohort study, we recruited 693 black and white women aged 21-24 y who had participated in the 10-y National Heart, Lung, and Blood Institute Growth and Health Study and measured YABM with the use of dual-energy X-ray absorptiometry. Dietary calcium and sedentary activity data, gathered through 3-d food records and self-reports of television-video viewing at 8 annual examinations, were averaged over 3 pubertal sta...

Journal of Clinical Oncology

5523 Background: We previously reported that baseline BMB are independently prognostic for overal... more 5523 Background: We previously reported that baseline BMB are independently prognostic for overall survival (OS) in men with castration resistant prostate cancer. We correlated BMB with outcomes in mHSPC as part of S1216, a phase III trial of ADT +/- the novel CYP17 inhibitor orteronel. Methods: Blood was obtained at study entry for bone resorption [C-telopeptide(CTx) & Pyridinoline(PYD)] & formation markers [C-terminal collagen propeptide(CICP) & bone alkaline phosphatase(BAP)]. With prior DSMC approval, patients were sampled to mask potential treatment effect. Logistic regression was used to assess if BMB elevation above median was prognostic for a PFS event w/in 2 years across pooled study treatment arms, adjusting for baseline variables (including disease extent, PSA, age, pre-randomization ADT, & presence of bone mets). An additional interaction term between BMB elevation & presence of bone mets was included; if significant, separate models were developed for men +/- bone mets....

Journal of Clinical Oncology

4547 Background: S0421, a phase III study of DOC +/- the endothelin antagonist ATR in CRPC pts wi... more 4547 Background: S0421, a phase III study of DOC +/- the endothelin antagonist ATR in CRPC pts with bone metastases, showed no overall survival (OS) benefit for DOC+ATR. While BMB may have a prognostic role in CRPC, their predictive role vis a vis bone-targeted therapy such as ATR is unknown. We prospectively assessed pre-treatment serum BMB from S0421 pts to validate their prognostic and predictive value. Methods: BMB for resorption (N-telopeptide, NTX and Pyridinoline, PYD) and formation (C-terminal collagen propeptide, CICP and bone alkaline phosphatase, BAP) were assayed [Quidel (PYD, CICP, BAP) and Wampole (NTX)]. Cox regression models for OS based on BMB adjusted for clinical variables were developed. An adjusted Cox model was fit with main effects and BMB x Treatment interaction to assess predictive value of ATR on OS. Results: Of 1,038 pts, 855 (82%) submitted baseline serum: 778 (91%) were usable and analyzable. Pt characteristics: median age = 69 years; PS 0-1 = 91%, Bisph...

The American Journal of Clinical Nutrition

Background Low calcium intake during pregnancy may cause maternal skeletal calcium mobilization t... more Background Low calcium intake during pregnancy may cause maternal skeletal calcium mobilization to meet fetal needs. The Recommended Dietary Allowance (RDA) for calcium in nonpregnant, pregnant, or lactating women aged 19–50 y is 1000 mg/d; most women in the United States report consuming 60–80% of the calcium RDA. An insufficient calcium intake could increase maternal bone loss during pregnancy and reduce bone recovery postpartum. Objectives The aim of this study was to determine the effect of maternal calcium supplementation on peripheral cortical and trabecular bone loss during pregnancy and bone gain postpartum. Methods A total of 64 women were enrolled in the study at 16 wk of gestation and randomly assigned to receive 1000 mg Ca/d or placebo for the remainder of the pregnancy. Measurements were performed at 16, 26, and 36 wk of pregnancy and at 4 and 12 mo postpartum for serum 25-hydroxyvitamin D and markers of bone turnover. Trabecular and cortical bone mineral density (BMD) ...

Nutrients, Jan 28, 2018

Calcium intake during adolescence is important for attainment of peak bone mass. Lactose maldiges... more Calcium intake during adolescence is important for attainment of peak bone mass. Lactose maldigestion is an autosomal recessive trait, leading to lower calcium intake. The Adequate Calcium Today study aimed to determine if a school-based targeted behavioral intervention over one year could improve calcium intake and bone mass in early adolescent girls. The school-randomized intervention was conducted at middle schools in six states over one school year. A total of 473 girls aged 10-13 years were recruited for outcome assessments. Bone mineral content (BMC) was determined by dual energy X-ray absorptiometry. Dietary calcium intake was assessed with a semi-quantitative food frequency questionnaire. Baseline calcium intake and BMC were not significantly different between groups. After the intervention period, there were no differences in changes in calcium intake and BMC at any site between groups. An unanticipated outcome was a greater increase in spinal BMC among lactose digesters th...

Medicine & Science in Sports & Exercise

Dietary fat and not calcium supplementation or dairy product consumption is associated with chang... more Dietary fat and not calcium supplementation or dairy product consumption is associated with changes in anthropometrics during a randomized, placebo-controlled energy-restriction trial

Current Developments in Nutrition, 2019

Objectives The glucostatic theory of appetite suggests that changes in blood glucose determine hu... more Objectives The glucostatic theory of appetite suggests that changes in blood glucose determine hunger and food intake behavior. While, this is the most popular theory to date it is not without controversy. Our goal was to evaluate this theory in an acute buffet meal challenge setting. Methods Overweight and obese (BMI: 32.9 ± 2.6 kg/m2) men and women (n = 21 and 50 respectively) were tested in a daylong satiety protocol. After an overnight fast, blood draws and self-reported visual analog scores for appetite questions were obtained at the following times: 2 times at fasting, 5 times after a breakfast meal providing 25% of energy need, and 12 times after a lunch meal with 40% of energy need 4 h after breakfast. Satiety hormones (plasma insulin, ghrelin, amylin, PYY, CCK, GIP and GLP-1) and plasma glucose and triglycerides were measured. A buffet dinner was offered beginning 4 h after lunch and participants self-selected the time and duration for this meal. The inter-meal interval bet...

Test meal ingredient list. (DOCX 14Â kb)

Nutrients, 2021

Background: Time restricted Feeding (TRF) is a dietary pattern utilized by endurance athletes, bu... more Background: Time restricted Feeding (TRF) is a dietary pattern utilized by endurance athletes, but there is insufficient data regarding its effects on performance and metabolism in this population. The purpose of this investigation was to examine the effects of a 16/8 TRF dietary pattern on exercise performance in trained male endurance runners. Methods: A 4-week randomized crossover intervention was used to compare an 8-h TRF to a 12-h normal diet (ND) feeding window. Exercise training and dietary intake were similar across interventions. Runners completed a dual-energy X-ray absorptiometry (DXA) scan to assess body composition, a graded treadmill running test to assess substrate utilization, and ran a 10 km time trial to assess performance. Results: There was a significant decrease in fat mass in the TRF intervention (−0.8 ± 1.3 kg with TRF (p = 0.05), vs. +0.1 ± 4.3 kg with ND), with no significant change in fat-free mass. Exercise carbon dioxide production (VCO2) and blood lacta...

The Journal of Nutrition, 2021

Background A variety of modifiable and nonmodifiable factors such as ethnicity, age, and diet hav... more Background A variety of modifiable and nonmodifiable factors such as ethnicity, age, and diet have been shown to influence bone health. Previous studies are usually limited to analyses focused on the association of a few a priori variables or on a specific subset of the population. Objective Dietary, physiological, and lifestyle data were used to identify directly modifiable and nonmodifiable variables predictive of bone mineral content (BMC) and bone mineral density (BMD) in healthy US men and women using machine-learning models. Methods Ridge, lasso, elastic net, and random forest models were used to predict whole-body, femoral neck, and spine BMC and BMD in healthy US men and women ages 18–66 y, with a BMI (kg/m2) of 18–44 (n = 313), using nonmodifiable anthropometric, physiological, and demographic variables; directly modifiable lifestyle (physical activity, tobacco use) and dietary (via FFQ) variables; and variables approximating directly modifiable behavior (circulating 25-hyd...

Current Developments in Nutrition, 2021

Objectives A variety of modifiable and non-modifiable factors such as ethnicity, age, and diet ha... more Objectives A variety of modifiable and non-modifiable factors such as ethnicity, age, and diet have been shown to influence bone health. Previous studies are usually limited to analyses focused on the association of a few a priori variables or on a specific subset of the population. The objective of this study was to use dietary, physiological, and lifestyle data to identify directly modifiable and non-modifiable variables predictive of bone mineral content (BMC) and bone mineral density (BMD) in healthy US men and women using machine learning models. Methods Ridge, lasso, elastic net, and random forest models were used to predict whole-body, femoral neck, and spine BMC and BMD in healthy US adults (n = 313) using non-modifiable anthropometric, physiological, and demographic variables, directly modifiable lifestyle (physical activity, tobacco use) and dietary (nutrient or food groups intake via food frequency questionnaire) variables, and variables approximating directly modifiable ...

Medical Research Archives, 2015

The American journal of clinical nutrition, 2003

An average daily calcium intake of 1300 mg is recommended for North American adolescents aged 9-1... more An average daily calcium intake of 1300 mg is recommended for North American adolescents aged 9-18 y. However, questions remain about these recommendations. We assessed whether there is a stage of puberty when dietary calcium is more strongly related to peak bone mass, as indicated by young adult bone mass (YABM); whether dietary calcium intake > 1000 mg/d in adolescence is associated with higher YABM; and whether race affects any of these associations between dietary calcium and YABM. Secondarily, we evaluated relations between sedentariness and YABM. In a retrospective cohort study, we recruited 693 black and white women aged 21-24 y who had participated in the 10-y National Heart, Lung, and Blood Institute Growth and Health Study and measured YABM with the use of dual-energy X-ray absorptiometry. Dietary calcium and sedentary activity data, gathered through 3-d food records and self-reports of television-video viewing at 8 annual examinations, were averaged over 3 pubertal sta...

Journal of Clinical Oncology

5523 Background: We previously reported that baseline BMB are independently prognostic for overal... more 5523 Background: We previously reported that baseline BMB are independently prognostic for overall survival (OS) in men with castration resistant prostate cancer. We correlated BMB with outcomes in mHSPC as part of S1216, a phase III trial of ADT +/- the novel CYP17 inhibitor orteronel. Methods: Blood was obtained at study entry for bone resorption [C-telopeptide(CTx) & Pyridinoline(PYD)] & formation markers [C-terminal collagen propeptide(CICP) & bone alkaline phosphatase(BAP)]. With prior DSMC approval, patients were sampled to mask potential treatment effect. Logistic regression was used to assess if BMB elevation above median was prognostic for a PFS event w/in 2 years across pooled study treatment arms, adjusting for baseline variables (including disease extent, PSA, age, pre-randomization ADT, & presence of bone mets). An additional interaction term between BMB elevation & presence of bone mets was included; if significant, separate models were developed for men +/- bone mets....

Journal of Clinical Oncology

4547 Background: S0421, a phase III study of DOC +/- the endothelin antagonist ATR in CRPC pts wi... more 4547 Background: S0421, a phase III study of DOC +/- the endothelin antagonist ATR in CRPC pts with bone metastases, showed no overall survival (OS) benefit for DOC+ATR. While BMB may have a prognostic role in CRPC, their predictive role vis a vis bone-targeted therapy such as ATR is unknown. We prospectively assessed pre-treatment serum BMB from S0421 pts to validate their prognostic and predictive value. Methods: BMB for resorption (N-telopeptide, NTX and Pyridinoline, PYD) and formation (C-terminal collagen propeptide, CICP and bone alkaline phosphatase, BAP) were assayed [Quidel (PYD, CICP, BAP) and Wampole (NTX)]. Cox regression models for OS based on BMB adjusted for clinical variables were developed. An adjusted Cox model was fit with main effects and BMB x Treatment interaction to assess predictive value of ATR on OS. Results: Of 1,038 pts, 855 (82%) submitted baseline serum: 778 (91%) were usable and analyzable. Pt characteristics: median age = 69 years; PS 0-1 = 91%, Bisph...

The American Journal of Clinical Nutrition

Background Low calcium intake during pregnancy may cause maternal skeletal calcium mobilization t... more Background Low calcium intake during pregnancy may cause maternal skeletal calcium mobilization to meet fetal needs. The Recommended Dietary Allowance (RDA) for calcium in nonpregnant, pregnant, or lactating women aged 19–50 y is 1000 mg/d; most women in the United States report consuming 60–80% of the calcium RDA. An insufficient calcium intake could increase maternal bone loss during pregnancy and reduce bone recovery postpartum. Objectives The aim of this study was to determine the effect of maternal calcium supplementation on peripheral cortical and trabecular bone loss during pregnancy and bone gain postpartum. Methods A total of 64 women were enrolled in the study at 16 wk of gestation and randomly assigned to receive 1000 mg Ca/d or placebo for the remainder of the pregnancy. Measurements were performed at 16, 26, and 36 wk of pregnancy and at 4 and 12 mo postpartum for serum 25-hydroxyvitamin D and markers of bone turnover. Trabecular and cortical bone mineral density (BMD) ...

Nutrients, Jan 28, 2018

Calcium intake during adolescence is important for attainment of peak bone mass. Lactose maldiges... more Calcium intake during adolescence is important for attainment of peak bone mass. Lactose maldigestion is an autosomal recessive trait, leading to lower calcium intake. The Adequate Calcium Today study aimed to determine if a school-based targeted behavioral intervention over one year could improve calcium intake and bone mass in early adolescent girls. The school-randomized intervention was conducted at middle schools in six states over one school year. A total of 473 girls aged 10-13 years were recruited for outcome assessments. Bone mineral content (BMC) was determined by dual energy X-ray absorptiometry. Dietary calcium intake was assessed with a semi-quantitative food frequency questionnaire. Baseline calcium intake and BMC were not significantly different between groups. After the intervention period, there were no differences in changes in calcium intake and BMC at any site between groups. An unanticipated outcome was a greater increase in spinal BMC among lactose digesters th...

Medicine & Science in Sports & Exercise