A Dairy Product to Reconstitute Enriched with Bioactive Nutrients Stops Bone Loss in High-Risk Menopausal Women without Pharmacological Treatment.

Osteoporosis is a multifactorial disease characterized by the loss of bone mass and deterioration of the internal structure of the bone, increasing the risk of fractures, and is becoming an economic and social problem. The main treatment is pharmacological, however, the population demands other therapies, such as foods with nutrients beneficial to bone health. Seventy-eight healthy menopausal women at risk of osteoporosis or untreated osteopenia were recruited for a randomized, parallel, double-blind clinical trial with two intervention groups: one group consumed a serving a day of the experimental enriched product (experimental group (EG)) and the other group (control group (CG)) consumed the same product without enrichment. The main objective was to compare the effect of consuming a dairy preparation to reconstitute, similar to yogurt when prepared, enriched in calcium, vitamin D, vitamin K, vitamin C, zinc, magnesium, L-leucine and probiotic (Lactobacillus plantarum 3547) on bone metabolism markers for 24 weeks. The EG showed a significantly increased bone mass compared to the CG (0.01 ± 0.03 vs. -0.01 ± 0.03 kg; p < 0.05). In addition, the EG maintained their bone mineral density (BMD) compared to the CG, whose BMD significantly decreased at the end of the study. For biochemical markers, the EG significantly increased the serum levels of the N-terminal propeptide of type I collagen (P1NP) bone formation marker (13.19 ± 25.17 vs. -4.21 ± 15.62 ng/mL; p < 0.05), and decreased the carbo-terminal telopeptide of type I collagen (CTx) bone resorption marker compared to the CG (-0.05 ± 0.19 vs. 0.04 ± 0.14 ng/mL; p < 0.05). On the other hand, the EG exhibited a significantly decreased systolic and diastolic blood pressure compared to the start of the study. Finally, the EG significantly increased their dietary calcium and vitamin D intake compared to the CG. In conclusion, the regular consumption of a dairy product to reconstitute enriched with bioactive nutrients improves bone health markers in menopausal women at risk of osteoporosis without pharmacological treatment.

Dried plum alleviates symptoms of inflammatory arthritis in TNF transgenic mice.

Dried plum (DP), a rich source of polyphenols has been shown to have bone-preserving properties in both animal models of osteoporosis and postmenopausal women. We evaluated if DP alleviated the destruction of joints in transgenic mice (TG) that overexpress human tumor necrosis factor (TNF), a genetic model of rheumatoid arthritis (RA). A four-week treatment of 20% DP diet in TG slowed the onset of arthritis and reduced bone erosions in the joints compared to TG on a regular diet. This was associated with fewer tartrate-resistant acid phosphatase (TRAP) positive cells, suggesting decreased osteoclastogenesis. A DP diet also produced significant protection of articular cartilage and reduction of synovitis. Cultures of human synovial fibroblast in the presence of TNF showed a significant increase in inflammatory interleukin (IL)-1ß, chemokines (monocyte chemoattractant protein-1: MCP1 & macrophage inflammatory protein-1 alpha: MIP1α), cartilage matrix metalloproteinases (MMP1&3), and an osteoclastogenic cytokine (receptor activator of nuclear factor-κB ligand: RANKL) compared to controls. Addition of neochlorogenic acid (NC), a major polyphenol in DP to these cultures resulted in down-regulation of these genes. In the cultures of mouse bone marrow macrophage, NC also repressed TNF-induced formation of osteoclasts and mRNA levels of cathepsin K and MMP9 through inhibition of nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1) expression and nuclear factor kappa B (NF-κB) activation. Our data suggested that dietary supplementation with DP inhibited TNF singling; leading to decreased erosions of bone and articular cartilage as well as synovitis.

Germinated Pigmented Rice (Oryza Sativa L. cv. Superhongmi) Improves Glucose and Bone Metabolisms in Ovariectomized Rats.

The effect of germinated Superhongmi, a reddish brown pigmented rice cultivar, on the glucose profile and bone turnover in the postmenopausal-like model of ovariectomized rats was determined. The ovariectomized Sprague-Dawley rats were randomly divided into three dietary groups (n = 10): normal control diet (NC) and normal diet supplemented with non-germinated Superhongmi (SH) or germinated Superhongmi (GSH) rice powder. After eight weeks, the SH and GSH groups showed significantly lower body weight, glucose and insulin concentrations, levels of bone resorption markers and higher glycogen and 17-ß-estradiol contents than the NC group. The glucose metabolism improved through modulation of adipokine production and glucose-regulating enzyme activities. The GSH rats exhibited a greater hypoglycemic effect and lower bone resorption than SH rats. These results demonstrate that germinated Superhongmi rice may potentially be useful in the prevention and management of postmenopausal hyperglycemia and bone turnover imbalance.

Fortification of Yogurts with Vitamin D and Calcium Enhances the Inhibition of Serum Parathyroid Hormone and Bone Resorption Markers: A Double Blind Randomized Controlled Trial in Women over 60 Living in a Community Dwelling Home.

OBJECTIVE: To evaluate whether fortification of yogurts with vitamin D and calcium exerts an additional lowering effect on serum parathyroid hormone (PTH) and bone resorption markers (BRM) as compared to iso-caloric and iso-protein dairy products in aged white women at risk of fragility fractures. DESIGN: A randomized double-blind controlled trial. SETTING: A community dwelling home. PARTICIPANTS: Forty-eight women over 60 years (mean age 73.4). INTERVENTION: Consumption during 84 days of two 125 g servings of either vitamin D and calcium-fortified yogurts (FY) at supplemental levels of 10 µg vitamin D3/d and 520 mg/d of calcium (total=800 mg/d), or non fortified control yogurts (CY) providing 280 mg/d of calcium. MEASUREMENTS: Serum changes from baseline (D0) to D28, D56 and D84 in 25OHD, PTH and in two BRM: Tartrate-resistant-acid-phosphatase-isoform-5b (TRAP5b) and carboxy-terminal-cross-linked-telopeptide of type-I-collagen (CTX). RESULTS: The 10 years risk of major and hip fractures were 13.1 and 5.0%, and 12.9 and 4.2 %, in FY and CY groups, respectively. From D0 to D84, serum 25OHD increased (mean±SE) from 34.3±2.4 to 56.3±2.4 nmol/L in FY (n=24) and from 35.0±2.5 to 41.3±3.0 nmol/L in CY (n=24), (P=0.00001). The corresponding changes in PTH were from 64.1±5.1 to 47.4±3.8 ng/L in FY and from 63.5±4.6 to 60.7±4.2 ng/L in CY (P=0.0011). After D84, TRAP5b was reduced significantly (P=0.0228) and CTX fell though not significantly (P=0.0773) in FY compared to CY. CONCLUSION: This trial in aged white women living in a community dwelling home at risk for osteoporotic fractures confirms that fortification of dairy products with vitamin D3 and calcium should provide a greater prevention of secondary hyperparathyroidism and accelerated bone resorption as compared to non-fortified equivalent foods.

Aspectos metabólicos e nutricionais do magnésio / Metabolic and nutritional aspects of magnesium

Estudos atuais têm mostrado inadequação na ingestão de diversos nutrientes, sendo o magnésio, em particular, um mineral com consumo reduzido pela população. Considerando a importância do magnésio no metabolismo e manutenção da homeostase do organismo, a escassez de dados sobre o consumo desse mineral, esta revisão visa trazer informações atualizadas sobre o metabolismo, biodisponibilidade e ingestão desse micronutriente. Foi conduzida uma revisão narrativa, sendo que o levantamento bibliográfico foi realizado nas bases de dados PubMed, SciELO, Lilacs, utilizando as seguintes palavras-chave: 'magnesium metabolism', 'bioavailability', 'intake'. A deficiência de magnésio pode decorrer da ingestão inadequada ou excreção aumentada, sendo a homeostase desse nutriente, em nosso organismo, regulada principalmente pelos rins. Existem fatores inibidores do processo de absorção do magnésio, como a presença na dieta de alimentos ricos em fitatos, oxalatos, fosfatos e fibras alimentares; e promotores, tais como a lactose e carboidratos. Observa-se que a ingestão média de magnésio pela população encontra-se em valores inferiores às recomendações das Dietary Reference Intakes. Assim, é evidente a existência de inadequação no consumo de magnésio, o que contribui para a manifestação de sua deficiência na população, sendo necessários estudos sobre o tema, considerando que o metabolismo desse mineral não está completamente elucidado, bem como suas interações com outros nutrientes ou substâncias da dieta (AU)

Recent studies have shown inadequate intake of various nutrients, and magnesium, in particular is a mineral with reduced consumption among the population. Therefore, considering the importance of magnesium metabolism in maintenance of homeostasis, the paucity of data regarding the consumption of this mineral, this review aims to bring current information on metabolism, bioavailability and intake of this micronutrient. A narrative review was conducted, and the literature was carried out in the databases PubMed, SciELO, Lilacs, using the following key words: 'magnesium metabolism', 'bioavailability', 'intake'. Magnesium deficiency can result from inadequate intake or increased excretion, and the homeostasis of this nutrient in our body is mainly regulated by the kidneys. There are factors that inhibit the absorption process of magnesium, such as the presence in the diet of foods rich in phytates, oxalates, phosphates and dietary fiber; and promoters, such as lactose, and carbohydrates. It is observed that the average intake values of magnesium by the population are lower than recommendations of the Dietary Reference Intakes. Thus, it is clear that there is inadequacy in magnesium consumption, which contributes to manifestation of their disability in the population, and studies on the topic are required, whereas the metabolism of this mineral is not fully elucidated, neither their interactions with other nutrients or dietary substances (AU)

Feeding blueberry diets to young rats dose-dependently inhibits bone resorption through suppression of RANKL in stromal cells.

Previous studies have demonstrated that weanling rats fed AIN-93G semi-purified diets supplemented with 10% whole blueberry (BB) powder for two weeks beginning on postnatal day 21 (PND21) significantly increased bone formation at PND35. However, the minimal level of dietary BB needed to produce these effects is, as yet, unknown. The current study examined the effects of three different levels of BB diet supplementation (1, 3, and 5%) for 35 days beginning on PND25 on bone quality, and osteoclastic bone resorption in female rats. Peripheral quantitative CT scan (pQCT) of tibia, demonstrated that bone mineral density (BMD) and content (BMC) were dose-dependently increased in BB-fed rats compared to controls (P<0.05). Significantly increased bone mass after feeding 5% BB extracts was also observed in a TEN (total enteral nutrition) rat model in which daily caloric and food intake was precisely controlled. Expression of RANKL (receptor activator of nuclear factor-κB ligand) a protein essential for osteoclast formation was dose-dependently decreased in the femur of BB animals. In addition, expression of PPARγ (peroxisome proliferator-activated receptor γ) which regulates bone marrow adipogenesis was suppressed in BB diet rats compared to non-BB diet controls. Finally, a set of in vitro cell cultures revealed that the inhibitory effect of BB diet rat serum on RANKL expression was more profound in mesenchymal stromal cells compared to its effect on mature osteoblasts, pre-adipocytes and osteocytes. These results suggest that inhibition of bone resorption may contribute to increased bone mass during early development after BB consumption.

Vitamin E decreases bone mass by stimulating osteoclast fusion.

Bone homeostasis is maintained by the balance between osteoblastic bone formation and osteoclastic bone resorption. Osteoclasts are multinucleated cells that are formed by mononuclear preosteoclast fusion. Fat-soluble vitamins such as vitamin D are pivotal in maintaining skeletal integrity. However, the role of vitamin E in bone remodeling is unknown. Here, we show that mice deficient in α-tocopherol transfer protein (Ttpa(-/-) mice), a mouse model of genetic vitamin E deficiency, have high bone mass as a result of a decrease in bone resorption. Cell-based assays indicated that α-tocopherol stimulated osteoclast fusion, independent of its antioxidant capacity, by inducing the expression of dendritic-cell-specific transmembrane protein, an essential molecule for osteoclast fusion, through activation of mitogen-activated protein kinase 14 (p38) and microphthalmia-associated transcription factor, as well as its direct recruitment to the Tm7sf4 (a gene encoding DC-STAMP) promoter. Indeed, the bone abnormality seen in Ttpa(-/-) mice was rescued by a Tm7sf4 transgene. Moreover, wild-type mice or rats fed an α-tocopherol-supplemented diet, which contains a comparable amount of α-tocopherol to supplements consumed by many people, lost bone mass. These results show that serum vitamin E is a determinant of bone mass through its regulation of osteoclast fusion.

Consumption of vitamin D-and calcium-fortified soft white cheese lowers the biochemical marker of bone resorption TRAP 5b in postmenopausal women at moderate risk of osteoporosis fracture.

The prevention of increased bone remodeling in postmenopausal women at low 10-y risk of osteoporotic fractures essentially relies on reinforcement of environmental factors known to positively influence bone health, among which nutrition plays an important role. In institutionalized women in their mid-eighties, we previously found that consumption of fortified soft plain cheese increased vitamin D, calcium, and protein intakes, reduced bone resorption biochemical markers, particularly the serum bone specific acid phosphatase tartrate resistant acid phosphatase, isoform 5b (TRAP 5b) that reflects osteoclast activity, and stimulated the serum bone anabolic factor insulin-like growth factor-I (IGF-I). Whether these effects occur in much younger women was tested in a prospective control study. Seventy-one healthy postmenopausal women aged 56.6 ± 3.9 y (mean ± SD) with low spontaneous supply of both Ca and vitamin D were randomized to consume daily (treated, n = 36) or not (controls, n = 35) two servings (2 × 100 g) of skimmed-milk, soft plain cheese for 6 wk. The vitamin D and Ca-fortified dairy product provided daily: 661 kJ, 2.5 µg vitamin D, 400 mg calcium, and 13.8 g protein. At the end of the intervention, the decrease in TRAP 5b and the increase in IGF-I were greater in the treated than in the control group (P < 0.02). The changes in serum carboxy terminal crosslinked telopeptide of type I collagen did not differ significantly between the two groups. In conclusion, like in elderly women, consumption by healthy postmenopausal women of a vitamin D and calcium-fortified dairy product that also increases the protein intake, reduces the serum concentration of the bone resorption biomarker TRAP 5b. This response, combined with the increase in serum IGF-I, is compatible with a nutrition-induced reduction in postmenopausal bone loss rate.

Consumption of legumes improves certain bone markers in ovariectomized rats.

Soybeans are known to protect against osteoporosis, but other legumes frequently consumed in Asia have not been studied to learn if they have a similar protective effect. This study investigated the hypothesis that consumption of soybean, mung bean, cowpea, and adzuki bean has beneficial effects on bone biomarkers in ovariectomized rats. Female Sprague-Dawley rats were either sham operated (sham; n = 7) or surgically ovariectomized and then fed a regular AIN-93M diet (OVX; n = 7) or AIN-93M containing soybean (n = 7), mung bean (n = 7), cowpea (n = 7), or adzuki beans (n = 7) for 10 weeks. No bean consumption significantly altered the body, subcutaneous fat, or uterus weight; however, consumption significantly increased the serum calcium/phosphorous ratio and decreased urinary calcium excretion compared with those of the OVX group. Serum concentration of 17ß-estradiol was significantly lower in the OVX group compared with that of the sham group and was lowest in the group fed OVX diet containing soybean. Serum osteocalcin concentration was significantly higher in all OVX rats given a diet with beans compared with the same diet without, but urinary deoxypyridinoline excretion was lowest in the group fed OVX diet containing cowpea. There were no significant differences in bone mineral density or bone mineral content of the right femur, tibia, or lumbar spine or in the trabecular bone volume of the tibia among the diet groups. In conclusion, the consumption of soybean, mung bean, cowpea, and adzuki bean in OVX rats improved osteocalcin, but only those fed cowpea showed decreased bone resorption biomarker, suggesting that cowpea may have the most protective effect on bone in OVX rats.

Nutritional approach for inhibiting bone resorption in institutionalized elderly women with vitamin D insufficiency and high prevalence of fracture.

BACKGROUND: Nutritional approach to the deterioration of bone integrity and increased fracture risk appears to be particularly appropriate in elderly women living in nursing homes. OBJECTIVE: To investigate the beneficial effect of the consumption of soft plain cheese on bone resorption markers in institutionalized elderly women. DESIGN: Prospective, randomized crossover controlled study. SETTING: Six French nursing homes or other institutions for elderly. PARTICIPANTS: Institutionalized women ≥ 65 years old with low vitamin D status and calcium intake below 700 mg/day. INTERVENTION: Consumption of soft plain cheese made of semi-skimmed milk which was fortified by both vitamin D3 (+1.25 µg/100g) and milk extracted Ca, thus achieving a total Ca content of 151 mg/100g as compared to about 118 mg/100g for standard fresh cheese. Two servings were taken every day during the 6 weeks that preceded or followed a period of 6 weeks without soft plain cheese consumption. MEASUREMENTS: The primary end point was the change in serum carboxy terminal cross-linked telopeptide of type I collagen (CTX) selected as a marker of bone resorption. RESULTS: 29 women aged 73-94 yr were selected, 21 of them with mean age 87.2±6.1 years remained compliant. The intervention increased calcium and protein intakes by 51% (904±228 vs. 599±122 mg/d) and 33 % (74.2±17.1 vs. 55.6±12.7 g/d, mean±SD), respectively. The dietary intervention was associated with a statistically significant increase in serum levels of both 25OHD and IGF-I, while those of [corrected] CTX and TRAP5b were significantly reduced. Compliance was 93,4 %. The daily consumption of two servings of soft plain cheese was well accepted in terms of tastiness and appetite suited portion size. CONCLUSION: This randomized crossover controlled trial demonstrates that in elderly women living in nursing homes, the consumption of soft plain cheese increasing the supply of vitamin D, calcium and proteins, could reduce bone resorption and thereby reduce the risk of incidental fragility fractures in the long term.

Zinc increases the effects of essential amino acids-whey protein supplements in frail elderly.

UNLABELLED: Protein undernutrition is frequent in the elderly. It contributes to the development of osteoporosis, possibly via lower IGF-I. Dietary zinc can influence IGF-I production. OBJECTIVES: To determine the influence of dietary zinc addition on IGF-I and bone turnover responses to essential amino acids-whey (EAA-W) protein supplements in frail elderly. DESIGN AND SETTING: A daily oral protein supplement was given to hospitalized patients for 4 weeks. On a randomized, double-blind basis, patients received either an additional 30 mg/day of zinc or control. PARTICIPANTS: Sixty-one hospitalized elderly aged 66.7 to 105.8, with a mini-nutritional assessment score between 17 and 24 were enrolled. MEASUREMENTS: Activities of daily living; dietary intakes; serum IGF-I, IGF-BP3, CrossLapsTM, osteocalcin and zinc were measured before and after 1, 2 and 4 weeks of protein supplementation. RESULTS: Serum IGF-I rapidly increased in both groups. Zinc accelerated this increase with changes of +48.2 +/- 14.3 and +22.4 +/- 4.7% (p < .05) by 1 week, in the zinc-supplemented and control groups, respectively. Zinc significantly decreased the serum bone resorption marker CrossLapsTM by already 1 week. Activities of daily living improved by +27.0 +/- 3.1 and +18.3 +/- 4.5% in zinc-supplemented and control groups, respectively. CONCLUSION: In the elderly, zinc supplementation accelerated the serum IGF-I response to EAA-W protein by 1 week and decreased a biochemical marker of bone resorption.

Natural products as alternative treatments for metabolic bone disorders and for maintenance of bone health.

Bone metabolism involves a complex balance between the deposition of matrix and mineralization and resorption. There is now good evidence that dietary components and herbal products can influence these processes, particularly by inhibiting bone resorption, thus having beneficial effects on the skeleton. For example, it has been reported that a number of common vegetables, including onion, garlic and parsley, can inhibit bone resorption in ovariectomized rats. Essential oils derived from sage, rosemary, thyme and other herbs inhibit osteoclast activity in vitro and in vitro and leading to an increase in bone mineral density. Soya, a rich source of isoflavones, has shown promising results and epidemiological evidence to support a use in maintaining bone health, and various traditional herbal formulae in Chinese and Ayurvedic medicine also have demonstrable effects in pharmacological models of osteoporosis. Recently, cannabinoids have been described as having positive effects on osteoblast differentiation, and the presence of cannabinoid receptors in bone tissue indicates a more complex role in bone metabolism than previously thought. The first part of this review briefly discusses normal bone metabolism and disorders caused by its disruption, with particular reference to osteoporosis and current pharmacological treatments. The effects of natural products on bone and connective tissue are then discussed, to include items of diet, herbal extracts and food supplements, with evidence for their efficacy outlined.

Protein nutrition as therapy for a genetic disorder of bone?

Bone formation is controlled by a network of transcription factors and signaling molecules. In this issue, , studying the role of the transcription factor ATF4 in a new mouse model of neurofibromatosis type I skeletal defects, demonstrate striking effects of changing dietary protein on bone formation abnormalities.

ATF4 mediation of NF1 functions in osteoblast reveals a nutritional basis for congenital skeletal dysplasiae.

The transcription factor ATF4 enhances bone formation by favoring amino acid import and collagen synthesis in osteoblasts, a function requiring its phosphorylation by RSK2, the kinase inactivated in Coffin-Lowry Syndrome. Here, we show that in contrast, RSK2 activity, ATF4-dependent collagen synthesis, and bone formation are increased in mice lacking neurofibromin in osteoblasts (Nf1(ob)(-/-) mice). Independently of RSK2, ATF4 phosphorylation by PKA is enhanced in Nf1(ob)(-/-) mice, thereby increasing Rankl expression, osteoclast differentiation, and bone resorption. In agreement with ATF4 function in amino acid transport, a low-protein diet decreased bone protein synthesis and normalized bone formation and bone mass in Nf1(ob)(-/-) mice without affecting other organ weight, while a high-protein diet overcame Atf4(-/-) and Rsk2(-/-) mice developmental defects, perinatal lethality, and low bone mass. By showing that ATF4-dependent skeletal dysplasiae are treatable by dietary manipulations, this study reveals a molecular connection between nutrition and skeletal development.

High-dose fish oil and antioxidants in Crohn's disease and the response of bone turnover: a randomised controlled trial.

Crohn's disease is associated with altered bone turnover that may be influenced by nutritional status, the systemic inflammatory response, cytokine production by circulating (peripheral blood) mononuclear cells (PBMC) and antioxidant micronutrient intake. High-dose fish oil is associated with reductions in disease relapse and inflammatory markers, and modulates PBMC function. The effect of fish oil plus antioxidants on bone turnover and PBMC function (the production of interferon-gamma and prostaglandin E2) in Crohn's disease was investigated in a randomised-controlled trial. Patients with currently or recently raised biochemical markers of inflammation (C-reactive protein > or = 6.9 mg/l or erythrocyte sedimentation rate > or =18 mm/h) received fish oil (providing 2.7 g/d EPA and DHA) and antioxidants (vitamins A, C and E, and Se) (n 31) or placebo (n 30) for 24 weeks. Bone turnover was assessed by measuring the concentrations of urinary deoxypyridinoline (bone resorption) and serum osteocalcin (bone formation). Fish oil plus antioxidants were associated with increases in EPA, DHA Se in plasma (all P < 0.01), and with a reduction in interferon-gamma production by mitogen-stimulated PBMC, which demonstrated a negative correlation with deoxypyridinoline/creatinine:osteocalcin ratio (r - 0.33, P = 0.009). There were no differences between the groups at 24 weeks in the response of deoxypyridinoline or osteocalcin or their ratio, or in nutritional status. Dietary supplementation in Crohn's disease with high intakes of EPA and DHA, as fish oil, plus antioxidants was associated with a modulated production of interferon-gamma by PBMC but not altered indices of bone turnover.

Nutrición y osteoporosis / No disponible

No disponible

Common herbs, essential oils, and monoterpenes potently modulate bone metabolism.

During our survey of herbs looking for activity on bone metabolism, we found that the dried leaves of sage strongly inhibit bone resorption. Therefore, we investigated several common herbs rich in essential oils (sage, rosemary, and thyme) and essential oils extracted from these herbs and other plants (oils of sage, rosemary, juniper, pine, dwarf pine, turpentine, and eucalyptus) as well as their monoterpene components (thujone, eucalyptol, camphor, borneol, thymol, alpha-pinene, beta-pinene, bornylacetate as well as menthol) and found that they inhibit bone resorption when added to the food of rats. Pine oil, used as a representative essential oil, protects an osteoporosis model, the aged ovariectomized rat, from bone loss. The monoterpenes borneol, thymol, and camphor are directly inhibitory in the osteoclast resorption pit assay. Nonpolar monoterpenes may require metabolism to be active in vitro, for example, cis-verbenol, a metabolite of alpha-pinene occurring in human urine, inhibits osteoclast activity in contrast to the parent compound. Within 30 min borneol inhibits the formation of actin rings, a characteristic of resorbing osteoclasts indicating cell polarization. Both the in vitro and the in vivo effects of borneol are reversible. Our study demonstrates for the first time that essential oils and monoterpenes are efficient inhibitors of bone resorption in the rat.

Effect of magnesium supplementation on the fractional intestinal absorption of 45CaCl2 in women with a low erythrocyte magnesium concentration.

The cosupplementation of magnesium with calcium has been suggested to be beneficial in the prevention of osteoporosis. We investigated the effect of magnesium supplementation on parameters of bone resorption and fractional 45Ca absorption. Twenty apparently healthy women with a mean age of 39.2 +/- 9.2 years and an erythrocyte magnesium concentration less than 1.97 mmol/L were recruited into a controlled magnesium supplementation trial. During weeks 1 to 4, they received a daily control preparation, potassium/sodium citrate malate (PSCM). During weeks 5 to 8, the subjects received magnesium citrate malate (MCM) equivalent to 250 mg magnesium per day. During the fourth and eighth weeks, blood was collected for measurement of the serum intact parathyroid hormone (PTH) concentration and serum and erythrocyte magnesium concentration. Urine was collected for measurement of calcium, magnesium, creatinine, and deoxypyridinoline excretion. On the final day of each treatment period, 5 microCi45CaCl2 was administered orally, and the isotope was traced in the blood and urine over 7 hours. Urinary calcium, 45Ca, and deoxypyridinoline excretion, as well as serum intact PTH levels, showed no statistically significant changes as a result of magnesium supplementation. However, urinary magnesium excretion increased by 31.1% (P < .005) while fractional 45Ca absorption decreased by 23.5% (P < .001) as a result of magnesium supplementation. It is concluded that magnesium supplementation does not result in changes in bone resorption, while the fractional intestinal absorption of 45Ca appears to decrease.

The effect of modifying dietary calcium intake pattern on the circadian rhythm of bone resorption.

In order to assess day-to-day variations of the circadian rhythm of biochemical bone resorption markers, urinary morning (6-8 a.m.) and evening (7-10 p.m.) samples from 35 individuals were monitored during 3 subsequent days. The bone-specific deoxypyridinoline (DPD) crosslinks of type I collagen followed a circadian rhythm in all individuals. In contrast, no such pattern was observed in the urinary hydroxyproline/creatinine and calcium/creatinine measurements. The DPD crosslink measurements showed a much larger difference between the morning and evening samples collected within 1 day compared with the variation between the samples collected in the morning or evening on subsequent days, indicating the importance of adequate timing of urine sampling for clinical trials aiming to monitor effects on bone resorption. The analysis of DPD crosslinks was then used to evaluate the effects of different patterns of dietary calcium intake on the circadian rhythm of bone resorption in osteoporotic patients. No significant effect on the circadian rhythm of the DPD crosslinks was found after concentrating the normal daily calcium intake to the evening (6-10 p.m.) during 8 days (n = 7). Ingestion of a dietary calcium supplement (600 mg) at 10 p.m. during 8 days (n = 7) resulted in an increased urinary calcium excretion in the morning, and a flattening of the circadian peak and nadir concentrations of urinary DPD/creatinine. The absolute levels of DPD/creatinine in the morning and evening urine samples, respectively, were not significantly altered compared with the control day. We conclude that dietary calcium supplementation in the evening only marginally affects the circadian rhythm of urinary DPD crosslinks in established osteoporosis patients.

Calcium supplementation suppresses bone turnover during weight reduction in postmenopausal women.

Bone mobilization, lowering of bone mineral density (BMD), and osteoporotic fractures are recognized in postmenopausal women with weight loss. Because a high-calcium intake suppresses bone loss in peri- and postmenopausal women, the present randomized, double-blind, placebo-controlled study was designed to test the hypothesis that calcium supplementation prevents net bone mobilization and consequent bone mineral loss during voluntary weight reduction in obese postmenopausal women. Subjects were placed on a moderate energy-restricted diet and either calcium supplementation (1 g/day) or placebo for 6 months. Body weight, bone turnover markers (pyridinium cross-links), osteocalcin, and parathyroid hormone (PTH) were measured at treatment weeks 1-5, 7, 10, 13, 16, 20, and 25. Total body BMD, insulin-like growth factor, 25-hydroxyvitamin D, and sex hormone binding globulin (SHBG) were measured at baseline and week 25. The calcium supplemented (n = 15; age 60.9 +/- 9.4 years, body mass index [BMI] 33.2 +/- 4.6 kg/m2) and placebo (n = 16; age 55.8 +/- 8.3 years, BMI 32.9 +/- 4.5 kg/m2) groups lost similar amounts of weight over the study interval (10.2 +/- 5.3% vs. 10.0 +/- 5.2%) and both groups increased SHBG (p < 0.001). There was a statistical effect of calcium supplementation during weight loss to suppress pyridinium cross-links, osteocalcin, and PTH (p < 0.05, < 0.01, and < 0.05, respectively). Loss of BMD tended to be greater in the placebo group by 1.4% (p < 0.08) after weight loss. One gram per day calcium supplementation normalizes the increased calcium-PTH axis activity and the elevated bone turnover rate observed during moderate voluntary energy restriction in postmenopausal women.