Query: Fosamax

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The role of phytic acid in legumes: antinutrient or beneficial function? <=SEP=> This review describes the present state of knowledge about phytic acid (phytate), which is often present in legume seeds. The antinutritional effects of phytic acid primarily relate to the strong chelating associated with its six reactive phosphate groups. Its ability to complex with proteins and particularly with minerals has been a subject of investigation from chemical and nutritional viewpoints. The hydrolysis of phytate into inositol and phosphates or phosphoric acid occurs as a result of phytase or nonenzymatic cleavage. Enzymes capable of hydrolysing phytates are widely distributed in micro-organisms, plants and animals. Phytases act in a stepwise manner to catalyse the hydrolysis of phytic acid. To reduce or eliminate the chelating ability of phytate, dephosphorylation of hexa- and penta-phosphate forms is essential since a high degree of phosphorylation is necessary to bind minerals. There are several methods of decreasing the inhibitory effect of phytic acid on mineral absorption (cooking, germination, fermentation, soaking, autolysis). Nevertheless, inositol hexaphosphate is receiving increased attention owing to its role in cancer prevention and/or therapy and its hypocholesterolaemic effect.

Inositol Hexakisphosphate Inhibits Osteoclastogenesis on RAW 264.7 Cells and Human Primary Osteoclasts <=SEP=> Background Inoxitol hexakisphosphate (IP6) has been found to have an important role in biomineralization and a direct effect inhibiting mineralization of osteoblasts in vitro without impairing extracellular matrix production and expression of alkaline phosphatase. IP6 has been proposed to exhibit similar effects to those of bisphosphonates on bone resorption, however, its direct effect on osteoclasts (OCL) is presently unknown. Methodology/Principal Findings The aim of the present study was to investigate the effect of IP6 on the RAW 264.7 monocyte/macrophage mouse cell line and on human primary osteoclasts. On one hand, we show that IP6 decreases the osteoclastogenesis in RAW 264.7 cells induced by RANKL, without affecting cell proliferation or cell viability. The number of TRAP positive cells and mRNA levels of osteoclast markers such as TRAP, calcitonin receptor, cathepsin K and MMP-9 was decreased by IP6 on RANKL-treated cells. On the contrary, when giving IP6 to mature osteoclasts after RANKL treatment, a significant increase of bone resorption activity and TRAP mRNA levels was found. On the other hand, we show that 1 µM of IP6 inhibits osteoclastogenesis of human peripheral blood mononuclear cells (PBMNC) and their resorption activity both, when given to undifferentiated and to mature osteoclasts. Conclusions/Significance Our results demonstrate that IP6 inhibits osteoclastogenesis on human PBMNC and on the RAW264.7 cell line. Thus, IP6 may represent a novel type of selective inhibitor of osteoclasts and prove useful for the treatment of osteoporosis.

Bisphosphonate-associated osteonecrosis of the jaw: report of a task force of the American Society for Bone and Mineral Research. <=SEP=> ONJ has been increasingly suspected to be a potential complication of bisphosphonate therapy in recent years. Thus, the ASBMR leadership appointed a multidisciplinary task force to address key questions related to case definition, epidemiology, risk factors, diagnostic imaging, clinical management, and future areas for research related to the disorder. This report summarizes the findings and recommendations of the task force. INTRODUCTION: The increasing recognition that use of bisphosphonates may be associated with osteonecrosis of the jaw (ONJ) led the leadership of the American Society for Bone and Mineral Research (ASBMR) to appoint a task force to address a number of key questions related to this disorder. MATERIALS AND METHODS: A multidisciplinary expert group reviewed all pertinent published data on bisphosphonate-associated ONJ. Food and Drug Administration drug adverse event reports were also reviewed. RESULTS AND CONCLUSIONS: A case definition was developed so that subsequent studies could report on the same condition. The task force defined ONJ as the presence of exposed bone in the maxillofacial region that did not heal within 8 wk after identification by a health care provider. Based on review of both published and unpublished data, the risk of ONJ associated with oral bisphosphonate therapy for osteoporosis seems to be low, estimated between 1 in 10,000 and <1 in 100,000 patient-treatment years. However, the task force recognized that information on incidence of ONJ is rapidly evolving and that the true incidence may be higher. The risk of ONJ in patients with cancer treated with high doses of intravenous bisphosphonates is clearly higher, in the range of 1-10 per 100 patients (depending on duration of therapy). In the future, improved diagnostic imaging modalities, such as optical coherence tomography or MRI combined with contrast agents and the manipulation of image planes, may identify patients at preclinical or early stages of the disease. Management is largely supportive. A research agenda aimed at filling the considerable gaps in knowledge regarding this disorder was also outlined.

Effect of phytic acid on the absorption, distribution, and endogenous excretion of zinc in rats. <=SEP=> Zinc metabolism in male rats was studied by combining nutritional balance methods with an analysis of 65Zn kinetics. The rats, two groups of 84 each, were fed zinc-adequate diets (33 ppm Zn) with either 0 (basal) or 2% phytic acid added as sodium phytate. A fourth-order exponential function described the time-course of 65Zn in plasma, and compartmental models were developed accordingly. Plasma zinc exchanged more rapidly with zinc in liver and kidneys than it did with zinc in testes, skeletal muscle, or bone. Total body zinc content (2.6 mg/100 g live body weight) measured chemically was about 9 times higher than estimates of exchangeable zinc in the body. Whole-body retention of 65Zn was higher and endogenous fecal zinc excretion was lower in rats fed phytate than in those fed the basal diet; these responses to phytate may reflect a homeostatic adjustment to decreased absorption of zinc. Respective values for apparent absorption and true absorption of zinc were 13 and 32% of zinc intake in rats fed phytate, and 19 and 46% of zinc intake in rats fed the basal diet. When whole grains or mature seeds constitute a major portion of the diet, the phytate: zinc molar ratio may approach that (60:1) used in our study. Whether or not phytic acid occurring naturally in foods affects zinc metabolism to the same extent as sodium phytate can not be determined from our study.

Phytate (myo-inositol hexaphosphate) and risk factors for osteoporosis. <=SEP=> Several risk factors seem to play a role in the development of osteoporosis. Phytate is a naturally occurring compound that is ingested in significant amounts by those with diets rich in whole grains. The aim of this study was to evaluate phytate consumption as a risk factor in osteoporosis. In a first group of 1,473 volunteer subjects, bone mineral density was determined by means of dual radiological absorptiometry in the calcaneus. In a second group of 433 subjects (used for validation of results obtained for the first group), bone mineral density was determined in the lumbar column and the neck of the femur. Subjects were individually interviewed about selected osteoporosis risk factors. Dietary information related to phytate consumption was acquired by questionnaires conducted on two different occasions, the second between 2 and 3 months after performing the first one. One-way analysis of variance or Student's t test was used to determine statistical differences between groups. Bone mineral density increased with increasing phytate consumption. Multivariate linear regression analysis indicated that body weight and low phytate consumption were the risk factors with greatest influence on bone mineral density. Phytate consumption had a protective effect against osteoporosis, suggesting that low phytate consumption should be considered an osteoporosis risk factor.

Protective effect of myo-inositol hexaphosphate (phytate) on bone mass loss in postmenopausal women. <=SEP=> INTRODUCTION: The objective of this paper was to evaluate the relationship between urinary concentrations of InsP6, bone mass loss and risk fracture in postmenopausal women. MATERIALS AND METHODS: A total of 157 postmenopausal women were included in the study: 70 had low (≤0.76 μM), 42 intermediate (0.76-1.42 μM) and 45 high (≥1.42 μM) urinary phytate concentrations. Densitometry values for neck were measured at enrollment and after 12 months (lumbar spine and femoral neck), and 10-year risk fracture was calculated using the tool FRAX(®). RESULTS: Individuals with low InsP6 levels had significantly greater bone mass loss in the lumbar spine (3.08 ± 0.65 % vs. 0.43 ± 0.55 %) than did those with high phytate levels. Moreover, a significantly greater percentage of women with low than with high InsP6 levels showed more than 2 % of bone mass loss in the lumbar spine (55.6 vs. 20.7 %). The 10-year fracture probability was also significantly higher in the low-phytate group compared to the high-phytate group, both in hip (0.37 ± 0.06 % vs 0.18 ± 0.04 %) and major osteoporotic fracture (2.45 ± 0.24 % vs 1.83 ± 0.11 %). DISCUSSION: It can be concluded that high urinary phytate concentrations are correlated with reduced bone mass loss in lumbar spine over 12 months and with reduced 10-year probability of hip and major osteoporotic fracture, indicating that increased phytate consumption can prevent development of osteoporosis.

Patient expectations on lipid-lowering drugs. <=SEP=> OBJECTIVE: The objective of this study was to assess expectations of effect when using statins in a treatment population. Further the aim was to examine factors, including history and concurrent risk of coronary heart disease, associated with a higher and lower treatment belief. METHODS: Eight hundred and twenty-nine (829) Swedish patients using statins completed postal questionnaires about their health, life style, cardiovascular risk factors and expectation of the treatment. Expected treatment benefit was used as outcome measurement. RESULTS: A medical history of coronary heart disease did not affect treatment expectations. Patients with a high risk of cardiovascular disease reported a slightly lower expectation of the treatment effect at a 10-year perspective (p<0.01) but not at shorter time perspectives. Low satisfaction with the explanation of the purpose of the treatment and a poor perceived control of own health was associated with a more negative view on treatment benefit. CONCLUSION: The rationale applied by physicians prescribing statins does not seem to relate to the patients' expectations, whereas factors relating to the patient-physician relationship, the social situation and the perceived control of health seem to affect patient belief. PRACTICE IMPLICATIONS: The association between patients' poor satisfaction of treatment explanation and a low belief in treatment benefits emphasizes the importance of the patient-physician communication. It is suggested that clinical tools are developed in order to identify patients with poor belief in treatment benefit since tailored education for this group might reduce the risk of non-compliance and subsequently reduce the risk of coronary heart disease.

Patients' Expectations of Screening and Preventive Treatments <=SEP=> PURPOSE An informed decision to accept a health care intervention requires an understanding of its likely benefit. This study assessed participants' estimates of the benefit, as well as minimum acceptable benefit, of screening for breast and bowel cancer and medication to prevent hip fracture and cardiovascular disease. METHODS Three general practitioners sent questionnaires to all registered patients aged 50 to 70 years. Patients agreeing to participate in the study were asked to estimate the number of events (fractures or deaths) prevented in a group of 5,000 patients undergoing each intervention over a period of 10 years, and to indicate the minimum number of events avoided by the intervention that they considered justified its use. The proportions of participants that overestimated each intervention's benefit were calculated, and univariate and multivariable analyses of predictors of response were performed. RESULTS The participation rate was 36%: 977 patients were invited to participate in the study, and 354 returned a completed questionnaire. Participants overestimated the degree of benefit conferred by all interventions: 90% of participants overestimated the effect of breast cancer screening, 94% overestimated the effect of bowel cancer screening, 82% overestimated the effect of hip fracture preventive medication, and 69% overestimated the effect of preventive medication for cardiovascular disease. Estimates of minimum acceptable benefit were more conservative, but other than for cardiovascular disease mortality prevention, most respondents indicated a minimum benefit greater than these interventions achieve. A lower level of education was associated with higher estimates of minimum acceptable benefit for all interventions. CONCLUSION Patients overestimated the risk reduction achieved with 4 examples of screening and preventive medications. A lower level of education was associated with higher minimum benefit to justify intervention use. This tendency to overestimate benefits may affect patients' decisions to use such interventions, and practitioners should be aware of this tendency when discussing these interventions with patients.

What benefit do patients expect from adding second and third antihypertensive drugs? <=SEP=> Aims To discover whether patients have the same expectations of benefit from taking the first and any additional drugs for the treatment of hypertension and to investigate any patient characteristics which predict willingness to take treatment. Methods This was an anonymous questionnaire survey carried out in a single primary care group. A random sample of patients from the practice list stratified by age and gender were surveyed to determine what benefit they required before deciding to receive first and subsequent drugs to treat hypertension. They were asked to indicate the largest number needing treatment for 5 years (NNT5) to prevent myocardial infarction in 1 (smallest benefit) that would persuade them of the need for treatment. Demographic information which might explain variability in enthusiasm for treatment was also collected. Results Participants required far higher benefit to consider drug treatment than expected with a mean NNT5 for the first treatment of 15.0 (95% CI 12.3, 17.8). Marginal benefit demanded for the addition of second and third treatments was at least as great with an NNT5 of 13.2 (95% CI 10.8, 15.7) and NNT5 of 11.0 (95% CI 8.6, 13.4). Additional factors influencing willingness to take treatment were gender with a difference in NNT5 between men and women of 7.1 (95% CI 1.7, 12.5), difficulty in making the decision (very easy vs very difficult) of 14.9 (95% CI 6.0, 23.8), and years in full time education 2.0 (95% CI 0.9, 3.0) for each additional year of education. Any slope of NNT5 with increasing number of tablets disappeared when gender, years in education, and difficulty in reaching a decision were taken into account simultaneously. Conclusions People may have greater expectation of benefit from antihypertensive drug treatment than it provides. They certainly do not view the addition of subsequent drugs as any lesser step than starting the first in terms of the benefit expected. Full understanding of both the risks and benefits may be of critical importance with those spending longer in full time education and those expending more effort in making the decision accepting more treatment. The discrepancy between benefit expected and that available demands further research into methods of determining patients’ expectations and informing individual patient decisions.

A way to reverse CAD? <=SEP=> PURPOSE: Plant-based nutrition achieved coronary artery disease (CAD) arrest and reversal in a small study. However, there was skepticism that this approach could succeed in a larger group of patients. The purpose of our follow-up study was to define the degree of adherence and outcomes of 198 consecutive patient volunteers who received counseling to convert from a usual diet to plant-based nutrition. METHODS: We followed 198 consecutive patients counseled in plant-based nutrition. These patients with established cardiovascular disease (CVD) were interested in transitioning to plant-based nutrition as an adjunct to usual cardiovascular care. We considered participants adherent if they eliminated dairy, fish, and meat, and added oil. RESULTS: Of the 198 patients with CVD, 177 (89%) were adherent. Major cardiac events judged to be recurrent disease totaled one stroke in the adherent cardiovascular participants—a recurrent event rate of .6%, significantly less than reported by other studies of plant-based nutrition therapy. Thirteen of 21 (62%) nonadherent participants experienced adverse events. CONCLUSION: Most of the volunteer patients with CVD responded to intensive counseling, and those who sustained plant-based nutrition for a mean of 3.7 years experienced a low rate of subsequent cardiac events. This dietary approach to treatment deserves a wider test to see if adherence can be sustained in broader populations. Plant-based nutrition has the potential for a large effect on the CVD epidemic.

Are preventive drugs preventive enough? A study of patients' expectation of benefit from preventive drugs. <=SEP=> OBJECTIVES: The study aimed to find the threshold of benefit for a hypothetical cholesterol-lowering drug below which the subject would not be prepared to take the drug. We also looked at whether proximity to the target event (myocardial infarction) and the subjects' views on drug taking affected this threshold. DESIGN: We studied 307 subjects using a written questionnaire and interview. Group 1 (102 subjects) had just been discharged from the coronary care unit. Group 2 (105 subjects) were taking cardio-protective drugs but had no recent history of myocardial infarction. Group 3 (100 subjects) had no history of myocardial infarction and were taking no cardio-protective drugs. RESULTS: Median values for the threshold of benefit below which the subject would not take the preventive drug were 20%, 20%, and 30% absolute risk reduction for Groups 1, 2 and 3 respectively. Median values for expectation of average prolongation of life were 12, 12 and 18 months respectively. Only 27% of subjects would take a drug offering 5% or less absolute risk reduction over five years. Subjects' views on medicinal drug taking in general and proximity to the target event were predictors of the acceptance of preventive drugs. Eighty percent of subjects wished to be told the numerical benefit of a preventive drug before starting on it. CONCLUSION: For the majority, the expectation of benefit from a preventive drug is higher than the actual benefit provided by current drug strategies. There is a tension between the patient's right to know about the chance of benefiting from a preventive drug and the likely reduction in uptake if they are so informed.

Neuroprotective effect of the natural iron chelator, phytic acid in a cell culture model of Parkinson's disease. <=SEP=> Disrupted iron metabolism and excess iron accumulation has been reported in the brains of Parkinson's disease (PD) patients. Because excessive iron can induce oxidative stress subsequently causing degradation of nigral dopaminergic neurons in PD, we determined the protective effect of a naturally occurring iron chelator, phytic acid (IP6), on 1-methyl-4-phenylpyridinium (MPP(+))-induced cell death in immortalized rat mesencephalic/dopaminergic cells. Cell death was induced with MPP(+) in normal and iron-excess conditions and cytotoxicity was measured by thiazolyl blue tetrazolium bromide (MTT assay) and trypan blue staining. Apoptotic cell death was also measured with caspase-3 activity, DNA fragmentation, and Hoechst nuclear staining. Compared to MPP(+) treatment, IP6 (30 micromol/L) increased cell viability by 19% (P<0.05) and decreased cell death by 22% (P<0.05). A threefold increase in caspase-3 activity (P<0.001) and a twofold increase in DNA fragmentation (P<0.05) with MPP(+) treatment was decreased by 55% (P<0.01) and 52% (P<0.05), respectively with IP6. Cell survival was increased by 18% (P<0.05) and 42% (P<0.001) with 30 and 100 micromol/L of IP6, respectively in iron-excess conditions. A 40% and 52% (P<0.001) protection was observed in caspase-3 activity with 30 and 100 micromol/L IP6, respectively in iron-excess condition. Similarly, a 45% reduction (P<0.001) in DNA fragmentation was found with 100 micromol/L IP6. In addition, Hoechst nuclear staining results confirmed the protective effect of IP6 against apoptosis. Similar protection was also observed with the differentiated cells. Collectively, our results demonstrate a significant neuroprotective effect of phytate in a cell culture model of PD.

Phytate in foods and significance for humans: food sources, intake, processing, bioavailability, protective role and analysis. <=SEP=> The article gives an overview of phytic acid in food and of its significance for human nutrition. It summarises phytate sources in foods and discusses problems of phytic acid/phytate contents of food tables. Data on phytic acid intake are evaluated and daily phytic acid intake depending on food habits is assessed. Degradation of phytate during gastro-intestinal passage is summarised, the mechanism of phytate interacting with minerals and trace elements in the gastro-intestinal chyme described and the pathway of inositol phosphate hydrolysis in the gut presented. The present knowledge of phytate absorption is summarised and discussed. Effects of phytate on mineral and trace element bioavailability are reported and phytate degradation during processing and storage is described. Beneficial activities of dietary phytate such as its effects on calcification and kidney stone formation and on lowering blood glucose and lipids are reported. The antioxidative property of phytic acid and its potentional anticancerogenic activities are briefly surveyed. Development of the analysis of phytic acid and other inositol phosphates is described, problems of inositol phosphate determination and detection discussed and the need for standardisation of phytic acid analysis in foods argued.

Surgical management of bisphosphonate-related osteonecrosis of the jaw in oncologic patients: a challenging problem. <=SEP=> AIM: Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a serious oral complication of supportive cancer therapy and the best method of treatment is still unclear. The purpose of this article is to analyze the type of treatment and outcome in a large patient cohort with BRONJ. PATIENTS AND METHODS: A total of 142 patients suffering from BRONJ at different sites were studied. All patients had been treated with intravenous bisphosphonates for various oncological disease. A descriptive analysis of all relevant patient data was performed with particular emphasis on surgical outcome. RESULTS: The mandible was affected in 58% of the patients. All but two patients had previous invasive dental procedures. The mean duration of bisphosphonate treatment was 37.1 months. A total of 86% of the patients were treated surgically, including sequestrectomies and mandibular resections. Soft-tissue reconstruction was achieved by local closure, myofascial flap using the mylohyoid muscle, and a vascularized fasciocutaneous flap in one patient. No bony reconstruction was performed. CONCLUSION: Surgical treatment of BRONJ remains challenging. There is only limited evidence that oncologic patients with BRONJ are candidates for vascularized bone reconstruction.

Ascorbic acid prevents the dose-dependent inhibitory effects of polyphenols and phytates on nonheme-iron absorption. <=SEP=> The effects of maize-bran phytate and of a polyphenol (tannic acid) on iron absorption from a white-bread meal were tested in 199 subjects. The phytate content was varied by adding different concentrations of phytate-free and ordinary maize bran. Iron absorption decreased progressively when maize bran containing increasing amounts of phytate phosphorous (phytate P) (from 10 to 58 mg) was given. The inhibitory effect was overcome by 30 mg ascorbic acid. The inhibitory effects of tannic acid (from 12 to 55 mg) were also dose dependent. Studies suggested that greater than or equal to 50 mg ascorbic acid would be required to overcome the inhibitory effects on iron absorption of any meal containing greater than 100 mg tannic acid. Our findings indicate that it may be possible to predict the bioavailability of iron in a diet if due account is taken of the relative content in the diet of the major promoters and inhibitors of iron absorption.

An algorithm to assess intestinal iron availability for use in dietary surveys <=SEP=> In nutritional epidemiology, it is often assumed that nutrient absorption is proportional to nutrient intake. For several nutrients, including non-haem Fe, this assumption may not hold. Depending on the nutrients ingested with non-haem Fe, its availability for absorption varies greatly. Therefore, using Fe intake to examine associations between Fe and health can impact upon the validity of findings. Previous algorithms that adjust Fe intakes for dietary factors known to affect absorption have been found to underestimate Fe absorption and, in the present study, perform poorly on independent dietary data. We have designed a new algorithm to adjust Fe intakes for the effects of ascorbic acid, meat, fish and poultry, phytate, polyphenols and Ca, incorporating not only absorption data from test meals but also current understanding of Fe absorption. In so doing, we have created a robust and universal Fe algorithm with potential for use in large cohorts. The algorithm described aims not to predict Fe absorption but available Fe in the gut, a measure we believe to be of greater use in epidemiological research. Available Fe is Fe available for absorption from the gastrointestinal tract, taking into account enhancing or inhibiting effects of dietary modifiers. Our algorithm successfully estimated average Fe availability in test meal data used to construct the algorithm and, unlike other algorithms tested, also provided plausible predictions when applied to independent dietary data. Future research is needed to evaluate the extent to which this algorithm is useful in epidemiological research to relate Fe to health outcomes.

Phytate levels and bone parameters: a retrospective pilot clinical trial. <=SEP=> This study evaluated the relationship between phytate urinary levels and bone characteristics in a large population of postmenopausal women. The study population consisted of 180 postmenopausal women who participated in a descriptive cross-sectional study. A urine sample was collected from each subject to determine phytate levels and the volunteers were divided into two groups according to phytate urinary concentration (i.e., low and high levels). Bone mineral density was determined in the lumbar spine and femoral neck of groups with low and high phytate urinary levels. Urinary levels of phytate were linked to dietary phytate consumption. Hence, bone mineral density values were significantly higher in the lumbar spines and femoral necks of women who consumed high levels of phytate than in women with low urinary phytate concentrations. Higher urinary levels of phytate correlated with higher bone mineral density in the lumbar spine and femoral necks of postmenopausal women. This finding demonstrates the potential use of phytate in the treatment of bone related diseases, as it uses a mechanism of action similar to some bisphosphonates.