A vitamin D deficient diet increases weight gain and compromises bone biomechanical properties without a reduction in BMD in adult female mice.

Vitamin D contributes to the development and maintenance of bone. Evidence suggests vitamin D status can also alter energy balance and gut health. In young animals, vitamin D deficiency (VDD) negatively affects bone mineral density (BMD) and bone microarchitecture, and these effects may also occur due to chronic ethanol intake. However, evidence is limited in mature models, and addressing this was a goal of the current study. Seven-month-old female C57BL/6 mice (n = 40) were weight-matched and randomized to one of four ad libitum diets: control, alcohol (Alc), vitamin D deficient (0 IU/d), or Alc+VDD for 8 weeks. A purified (AIN-93) diet was provided with water or alcohol (10 %) ad libitum. Body weight and food intake were recorded weekly, and feces were collected at 0, 4, and 8 weeks. At the age of 9 months, intestinal permeability was assessed by oral gavage of fluorescein isothiocyanate-dextran. Thereafter, bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry. The microarchitecture of the distal femur was assessed by micro-computed tomography and biomechanical properties were evaluated by cyclic reference point indentation. VDD did not affect BMD or most bone microarchitecture parameters, however, the polar moment of inertia (p < 0.05) was higher in the VDD groups compared to vitamin D sufficient groups. VDD mice also had lower whole bone water content (p < 0.05) and a greater average unloading slope (p < 0.01), and energy dissipated (p < 0.01), indicating the femur displayed a brittle phenotype. In addition, VDD caused a greater increase in energy intake (p < 0.05), weight gain (p < 0.05), and a trend for higher intestinal permeability (p = 0.08). The gut microbiota of the VDD group had a reduction in alpha diversity (p < 0.05) and a lower abundance of ASVs from Rikenellaceae, Clostridia_UCG-014, Oscillospiraceae, and Lachnospiraceae (p < 0.01). There was little to no effect of alcohol supplementation on outcomes. Overall, these findings suggest that vitamin D deficiency causes excess weight gain and reduces the biomechanical strength of the femur as indicated by the higher average unloading slope and energy dissipated without an effect on BMD in a mature murine model.

Saturated Fatty Acids and Omega-3 Polyunsaturated Fatty Acids Improve Metabolic Parameters in Ovariectomized Female Mice.

In menopausal and postmenopausal women, the risk for obesity, cardiovascular disease, osteoporosis, and gut dysbiosis are elevated by the depletion of 17ß-estradiol. A diet that is high in omega-6 polyunsaturated fatty acids (PUFAs), particularly linoleic acid (LA), and low in saturated fatty acids (SFAs) found in coconut oil and omega-3 PUFAs may worsen symptoms of estrogen deficiency. To investigate this hypothesis, ovariectomized C57BL/6J and transgenic fat-1 mice, which lower endogenous omega-6 polyunsaturated fatty acids, were treated with either a vehicle or estradiol benzoate (EB) and fed a high-fat diet with a high or low PUFA:SFA ratio for ~15 weeks. EB treatment reversed obesity, glucose intolerance, and bone loss in ovariectomized mice. fat-1 mice fed a 1% LA diet experienced reduced weight gain and adiposity, while those fed a 22.5% LA diet exhibited increased energy expenditure and activity in EB-treated ovariectomized mice. Coconut oil SFAs and omega-3 FAs helped protect against glucose intolerance without EB treatment. Improved insulin sensitivity was observed in wild-type and fat-1 mice fed 1% LA diet with EB treatment, while fat-1 mice fed 22.5% LA diet was protected against insulin resistance without EB treatment. The production of short-chain fatty acids by gut microbial microbiota was linked to omega-3 FAs production and improved energy homeostasis. These findings suggest that a balanced dietary fatty acid profile containing SFAs and a lower ratio of omega-6:omega-3 FAs is more effective in alleviating metabolic disorders during E2 deficiency.

Low-vitamin-D diet lowers cerebral serotonin concentration in mature female mice.

Low circulating 25-hydroxyvitamin D (25OHD) is commonly found in obese individuals and is often attributed to a volume dilution effect of adipose tissue. However, low vitamin D (LD) intake may contribute to the obesity itself. In this study, we examine whether low vitamin D status contributes to increased food intake and weight gain and can be explained by altered brain serotonin metabolism in 8-month-old female C57BL/6J mice. In a first experiment, mice were fed a 45% high-fat diet (HFD) containing different amounts of vitamin D at low (100 IU/kg), normal (1,000 IU/kg) or high (10,000 IU/kg) intake. After 10 weeks, mice fed LD had greater energy intake, weight gain, total and hepatic fat than the higher vitamin D groups (P < .05). In a second experiment, mice were examined for the central serotonin regulation of food intake after a 10% normal-fat diet (NFD) or 45% HFD containing low (100 IU/kg) or normal (1000 IU/kg) vitamin D. After 10 weeks, both HFD and LD diets attenuated circulating 25OHD concentration. Additionally, LD intake lowered cortical serotonin level, regardless of dietary fat intake (P < .05). In the arcuate and raphe nuclei, gene expression of vitamin D 1α-hydroxylase was lower due to LD during HFD feeding (P < .05). Tryptophan hydroxylase-2 and serotonin reuptake transporter gene expression was not altered due to LD. Overall, these findings suggest that a LD diet alters peripheral 25OHD, reduces central serotonin, and may contribute to weight gain in an obesogenic environment.

Three Doses of Vitamin D and Cognitive Outcomes in Older Women: A Double-Blind Randomized Controlled Trial.

Vitamin D may affect cognitive performance, but previous studies are either short term or observational. We conducted a randomized controlled trial of vitamin D supplementation on domain-specific cognitive measures in postmenopausal women. Overweight/obese women with serum 25-hydroxyvitamin D (25OHD) levels less than 30 ng/mL were recruited. Vitamin D3 supplementation (600, 2,000, or 4,000 IU/d) was randomly assigned in a double-blinded manner for 1 year. Serum 25-hydroxyvitamin D, osteocalcin (total and undercarboxylated), amyloid beta, parathyroid hormone, and estradiol were analyzed before and after supplementation. Cognitive tests were administered after treatment. The women (58 ± 6 years; body mass index, 30.0 ± 3.5 kg/m2) had a baseline serum 25-hydroxyvitamin D level of 22.6 ± 5.8 ng/mL that increased to 30.2 ± 5.6, 36.0 ± 4.9, and 40.8 ± 7.0 ng/mL in the 600, 2,000, and 4,000 IU/d groups, respectively (p < .001). Participants taking 2,000 IU/d compared to other doses performed better in learning and memory tests (p < .05), yet the 4,000 IU/d group had a slower reaction time compared to the 600 IU/d group. Multiple regression indicated that serum undercarboxylated osteocalcin predicted tasks associated with reaction time and executive function, whereas body mass index and parathyroid hormone negatively predicted reaction time and executive function (p ≤ .01). These data suggest that vitamin D has differential effects on domain-specific cognitive measures and that a higher dose may negatively affect reaction time.

Appetite and Gut Hormones Response to a Putative α-Glucosidase Inhibitor, Salacia Chinensis, in Overweight/Obese Adults: A Double Blind Randomized Controlled Trial.

Animal studies indicate Salacia reduces body weight, possibly due to its α-glucosidase inhibitor (α-GI) properties, but this has not been examined previously. In this study, a randomized, placebo-controlled, three-way cross-over design was used to evaluate whether Salacia Chinensis (SC) reduces appetite in healthy overweight/obese individuals (body mass index 28.8 ±3.6 kg/m²; 32 ± 12 years). Forty-eight participants were fasted overnight and consumed a dose of SC (300 or 500 mg) or placebo with a fixed breakfast meal at each visit. Appetite sensations, glycemic indices and gastrointestinal peptides were measured. Results indicated that SC had no effect on postprandial appetite. However, in women, hunger was reduced by SC compared to placebo at multiple time points (300 mg; p < 0.05), but not in men. Area under the curve (AUC) for serum glucose, insulin and amylin was attenuated with SC compared to placebo (p < 0.05). Glucagon like peptide-1 had two peaks after the meal, but the AUC did not differ between groups. The AUC of peak areas for peptide YY and ghrelin were greater for SC than placebo (p < 0.05). These findings indicate that Salacia decreases glycemic indices supporting its role as an α-GI, and affects certain gastrointestinal peptides suggesting it may be an appetite modulator.

Essential Nutrient Interactions: Does Low or Suboptimal Magnesium Status Interact with Vitamin D and/or Calcium Status?

Although much is known about magnesium, its interactions with calcium and vitamin D are less well studied. Magnesium intake is low in populations who consume modern processed-food diets. Low magnesium intake is associated with chronic diseases of global concern [e.g., cardiovascular disease (CVD), type 2 diabetes, metabolic syndrome, and skeletal disorders], as is low vitamin D status. No simple, reliable biomarker for whole-body magnesium status is currently available, which makes clinical assessment and interpretation of human magnesium research difficult. Between 1977 and 2012, US calcium intakes increased at a rate 2-2.5 times that of magnesium intakes, resulting in a dietary calcium to magnesium intake ratio of >3.0. Calcium to magnesium ratios <1.7 and >2.8 can be detrimental, and optimal ratios may be ∼2.0. Background calcium to magnesium ratios can affect studies of either mineral alone. For example, US studies (background Ca:Mg >3.0) showed benefits of high dietary or supplemental magnesium for CVD, whereas similar Chinese studies (background Ca:Mg <1.7) showed increased risks of CVD. Oral vitamin D is widely recommended in US age-sex groups with low dietary magnesium. Magnesium is a cofactor for vitamin D biosynthesis, transport, and activation; and vitamin D and magnesium studies both showed associations with several of the same chronic diseases. Research on possible magnesium and vitamin D interactions in these human diseases is currently rare. Increasing calcium to magnesium intake ratios, coupled with calcium and vitamin D supplementation coincident with suboptimal magnesium intakes, may have unknown health implications. Interactions of low magnesium status with calcium and vitamin D, especially during supplementation, require further study.

Zinc Supplementation Increases Procollagen Type 1 Amino-Terminal Propeptide in Premenarcheal Girls: A Randomized Controlled Trial.

BACKGROUND: Data have shown that healthy children and adolescents have an inadequate intake of zinc, an essential nutrient for growth. It is unclear whether zinc supplementation can enhance bone health during this rapid period of growth and development. OBJECTIVE: The primary aim of this study was to determine the effect of zinc supplementation on biochemical markers of bone turnover and growth in girls entering the early stages of puberty. The secondary aim was to test moderation by race, body mass index (BMI) classification, and plasma zinc status at baseline. METHODS: One hundred forty seven girls aged 9-11 y (46% black) were randomly assigned to a daily oral zinc tablet (9 mg elemental zinc; n = 75) or an identical placebo (n = 72) for 4 wk. Fasting plasma zinc, procollagen type 1 amino-terminal propeptide (P1NP; a bone formation marker), carboxy-terminal telopeptide region of type 1 collagen (ICTP; a bone resorption marker), and insulin-like growth factor I (IGF-I) were assessed at baseline and post-test. Additional markers of bone formation (osteocalcin) and resorption (urinary pyridinoline and deoxypyridinoline) were also measured. RESULTS: Four weeks of zinc supplementation increased plasma zinc concentrations compared with placebo [mean change, 1.8 µmol/L (95% CI: 1.0, 2.6) compared with 0.2 µmol/L (95% CI: -0.3, 0.7); P < 0.01]. Zinc supplementation also increased serum P1NP concentrations compared with placebo [mean change, 23.8 µmol/L (95% CI: -14.9, 62.5) compared with -31.0 µmol/L (95% CI: -66.4, 4.2); P = 0.04). There was no effect from zinc supplementation on osteocalcin, ICTP, pyridinoline, deoxypyridinoline, or IGF-I. There was no moderation by race, BMI classification, or plasma zinc status at baseline. CONCLUSIONS: Our data suggest that 4 wk of zinc supplementation increases bone formation in premenarcheal girls. Further studies are needed to determine whether supplemental zinc can improve childhood bone strength. This trial was registered at clinicaltrials.gov as NCT01892098.

Vitamin D supplementation and calcium absorption during caloric restriction: a randomized double-blind trial.

BACKGROUND: Weight loss (WL) is associated with a decrease in calcium absorption and may be one mechanism that induces bone loss with weight reduction. OBJECTIVE: Because vitamin D supplementation has been shown to increase true fractional calcium absorption (TFCA), the goal of this study was to examine the effect of vitamin D during WL or weight maintenance (WM). DESIGN: A randomized, placebo-controlled, double-blind 6-wk study was conducted in 82 postmenopausal women [BMI (in kg/m(2); ±SD): 30.2 ± 3.7] with 25-hydroxyvitamin D [25(OH)D] concentrations <70 nmol/L during either WL or WM. All women were given 10 µg vitamin D(3)/d and 1.2 g Ca/d and either weekly vitamin D(3) (375 µg) or a placebo equivalent to 63 µg (2500 IU)/d and 10 µg (400 IU)/d, respectively. We measured TFCA with the use of dual-stable isotopes, 25(OH)D, parathyroid hormone, estradiol, calcitriol, and urinary calcium at baseline and 6 wk in weight loss and vitamin D(3)-supplementation (WL-D; n = 19), weight maintenance and vitamin D(3)-supplementation (WM-D; n = 20), weight loss and placebo (n = 22), and weight maintenance and placebo (n = 21) groups. RESULTS: WL groups lost 3.8 ± 1.1% of weight with no difference between vitamin D(3) supplementation and the placebo. The rise in serum 25(OH)D was greatest in the WL-D group (19.8 ± 14.5 nmol/L) compared with in WM-D (9.1 ± 10.3 nmol/L) and placebo groups (1.5 ± 10.9 nmol/L). TFCA increased with vitamin D(3) supplementation compared with placebo treatment (P < 0.01) and decreased during WL compared with WM. Serum 25(OH)D or 1,25-dihyroxyvitamin D did not correlate with TFCA. CONCLUSION: These data show that vitamin D supplementation increases TFCA and that WL decreases TFCA and suggest that, when calcium intake is 1.2 g/d, either 10 or 63 µg vitamin D/d is sufficient to maintain the calcium balance. This trial was registered at clinicaltrials.gov as NCT00473031.

Blood lead levels and bone turnover with weight reduction in women.

High bone turnover states are known to raise blood lead levels (BPb). Caloric restriction will increase bone turnover, yet it remains unknown if weight reduction increases BPb due to mobilization of skeletal stores. We measured whole blood Pb levels ((206)Pb) by inductively coupled plasma mass spectrometry in 73 women (age 24-75 years; BMI 23- 61 kg/m(2)) before and after 6 months of severe weight loss (S-WL), moderate weight loss (M-WL), or weight maintenance (WM). Baseline BPb levels were relatively low at 0.2-6.0 microg/dl, and directly associated with age (r=0.49, P<0.0001). After severe WL (-37.4+/-9.3 kg, n=17), BPb increased by 2.1+/-3.9 microg/dl (P<0.05), resulting in BPb levels of 1.3-12.5 microg/dl. M-WL (-5.6+/-2.7 kg, n=39) and WM (0.3+/-1.3 kg, n=17) did not result in an increase in BPb levels (0.5+/-3.2 and 0.0+/-0.7 microg/dl, M-WL and WM, respectively). BPb levels increased more with greater WL (r=0.24, P<0.05). Bone turnover markers increased only with severe WL and were directly correlated with WL. At baseline, higher calcium intake was associated with lower BPb (r=-0.273, P<0.02), however, this association was no longer present after 6 months. Severe weight reduction in obese women increases skeletal bone mobilization and BPb, but values remain well below levels defined as Pb overexposure.

The major green tea polyphenol, (-)-epigallocatechin-3-gallate, inhibits obesity, metabolic syndrome, and fatty liver disease in high-fat-fed mice.

In this study, we investigated the effects of the major green tea polyphenol, (-)-epigallocatechin-3-gallate (EGCG), on high-fat-induced obesity, symptoms of the metabolic syndrome, and fatty liver in mice. In mice fed a high-fat diet (60% energy as fat), supplementation with dietary EGCG treatment (3.2 g/kg diet) for 16 wk reduced body weight (BW) gain, percent body fat, and visceral fat weight (P < 0.05) compared with mice without EGCG treatment. The BW decrease was associated with increased fecal lipids in the high-fat-fed groups (r(2) = 0.521; P < 0.05). EGCG treatment attenuated insulin resistance, plasma cholesterol, and monocyte chemoattractant protein concentrations in high-fat-fed mice (P < 0.05). EGCG treatment also decreased liver weight, liver triglycerides, and plasma alanine aminotransferase concentrations in high-fat-fed mice (P < 0.05). Histological analyses of liver samples revealed decreased lipid accumulation in hepatocytes in mice treated with EGCG compared with high-fat diet-fed mice without EGCG treatment. In another experiment, 3-mo-old high-fat-induced obese mice receiving short-term EGCG treatment (3.2 g/kg diet, 4 wk) had decreased mesenteric fat weight and blood glucose compared with high-fat-fed control mice (P < 0.05). Our results indicate that long-term EGCG treatment attenuated the development of obesity, symptoms associated with the metabolic syndrome, and fatty liver. Short-term EGCG treatment appeared to reverse preexisting high-fat-induced metabolic pathologies in obese mice. These effects may be mediated by decreased lipid absorption, decreased inflammation, and other mechanisms.

Overweight postmenopausal women lose bone with moderate weight reduction and 1 g/day calcium intake.

UNLABELLED: Overweight postmenopausal women may be more susceptible to bone loss with weight reduction than previously studied obese women. The influence of energy restriction and Ca intake on BMD was assessed in 66 individuals. Weight reduction resulted in bone loss at several sites in women consuming 1 g Ca/day and was mitigated with higher calcium intake at 1.7 g/day. INTRODUCTION: Bone loss is associated with weight loss in obese postmenopausal women and can be prevented with calcium (Ca) supplementation. However, because bone loss caused by weight loss may be greater in overweight than obese women, it is not clear whether Ca supplementation is also beneficial in overweight women. MATERIALS AND METHODS: We assessed the influence of caloric restriction at two levels of Ca intake on BMD and BMC in 66 overweight postmenopausal women (age, 61 +/- 6 years; body mass index, 27.0 +/- 1.8 kg/m2). Subjects completed either a 6-month energy-restricted diet (WL, n = 47) and lost 9.3 +/- 3.9 % weight or maintained weight (WM; 1 g Ca/day, n = 19). Participants in the WL group were randomly assigned to either normal (1 g/day; WL NL-Ca) or high (1.7 g/day; WL Hi-Ca) Ca intake. Regional BMD and BMC were measured at baseline and after 6 months. RESULTS: During normal Ca intake, trochanter BMD and BMC and total spine BMD were decreased more in WL than WM women (p < 0.05). The WL NL-Ca group lost more trochanter BMD (-4.2 +/- 4.1%) and BMC (-4.8 +/- 7.1%) than the WL Hi-Ca group (-1.4 +/- 5.6% and -1.1 +/- 8.1%, respectively; p < 0.05). There were no significant changes in BMD or BMC at the femoral neck in any group. Weight loss correlated with trochanter BMD loss (r = 0.687, p < 0.001) in the WL NL-Ca group. CONCLUSION: Despite an intake of 1 g Ca/day, bone loss occurred at some sites because of weight loss. Calcium intake of 1.7 g/day will minimize bone loss during weight loss in postmenopausal overweight women.

Effect of calcium supplementation on weight and fat loss in women.

Data suggest that a diet deficient in calcium is associated with higher body weight and that augmenting calcium intake may reduce weight and fat gain or enhance loss. Our aim was to determine whether calcium supplementation during a weight loss intervention affects body fat or weight loss. Data were combined from three separate 25-wk randomized, double blind, placebo-controlled trials of 1000 mg/d calcium supplementation in 100 premenopausal and postmenopausal women. The primary outcome measures were change in body weight and fat mass adjusted for baseline values. There were no significant differences in body weight or fat mass change between the placebo and the calcium-supplemented groups in the pooled analysis (adjusted mean +/- SE; body weight, placebo -6.2 +/- 0.7 vs. Ca -7.0 +/- 0.7 kg; fat mass, placebo -4.5 +/- 0.6 vs. Ca -5.5 +/- 0.6 kg), and no significant interactions of calcium supplementation with menopausal/diet status. Analysis as separate trials also found no significant differences between the placebo and the calcium groups. Calcium supplementation did not significantly affect amount of weight or fat lost by women counseled to follow a moderately restricted diet for 25 wk. Nevertheless, the magnitude and direction of the differences for group means are consistent with a hypothesized small effect.

Bone and gastric bypass surgery: effects of dietary calcium and vitamin D.

OBJECTIVE: To examine bone mass and metabolism in women who had previously undergone Roux-en-Y gastric bypass (RYGB) and determine the effect of supplementation with calcium (Ca) and vitamin D. RESEARCH METHODS AND PROCEDURES: Bone mineral density and bone mineral content (BMC) were examined in 44 RYGB women (> or = 3 years post-surgery; 31% weight loss; BMI, 34 kg/m(2)) and compared with age- and weight-matched control (CNT) women (n = 65). In a separate analysis, RYGB women who presented with low bone mass (n = 13) were supplemented to a total 1.2 g Ca/d and 8 microg vitamin D/d over 6 months and compared with an unsupplemented CNT group (n = 13). Bone mass and turnover and serum parathyroid hormone (PTH) and 25-hydroxyvitamin D were measured. RESULTS: Bone mass did not differ between premenopausal RYGB and CNT women (42 +/- 5 years), whereas postmenopausal RYGB women (55 +/- 7 years) had higher bone mineral density and BMC at the lumbar spine and lower BMC at the femoral neck. Before and after dietary supplementation, bone mass was similar, and serum PTH and markers of bone resorption were higher (p < 0.001) in RYGB compared with CNT women and did not change significantly after supplementation. DISCUSSION: Postmenopausal RYGB women show evidence of secondary hyperparathyroidism, elevated bone resorption, and patterns of bone loss (reduced femoral neck and higher lumbar spine) similar to other subjects with hyperparathyroidism. Although a modest increase in Ca or vitamin D does not suppress PTH or bone resorption, it is possible that greater dietary supplementation may be beneficial.