Biomarkers of bone health appropriate for evaluating functional foods designed to reduce risk of osteoporosis

Calcium carbonate-enriched pumpkin affects calcium status in ovariectomized rats

Calcium carbonate (CaCO₃)-enriched pumpkin may serve as a good source of calcium for patients diagnosed with osteoporosis. In this study, we aimed to determine the effect of CaCO₃-enriched pumpkin on Ca status in ovariectomized rats. The study included 40 female Wistar rats divided into five groups (n = 8). One group was fed with a standard diet (control group), while the other four groups were ovariectomized and received a standard diet (control ovariectomized group), or a diet containing CaCO₃-enriched pumpkin, alendronate, or both. The nutritional intervention lasted 12 weeks, and then the rats were euthanized. Tissue and blood samples were collected and assessed for the levels of total Ca, estradiol, parathyroid hormone, and procollagen type I N propeptide. In addition, a histological analysis was performed on femurs. The results of the study suggest that CaCO₃-enriched pumpkin can increase Ca content in femurs and improve bone recovery in ovariectomized rats. Furthermore, enriched pumpkin contributes to Ca accumulation in the kidneys, and this effect is more pronounced in combination with alendronate.

Effects of Calcium Lactate-Enriched Pumpkin on Calcium Status in Ovariectomized Rats

This study aimed to evaluate the effects of enriched pumpkin on calcium status in ovariectomized rats. The study was conducted in sixty female Wistar rats, which were divided into six groups: a group fed a standard diet (C) and five ovariectomized groups fed a standard diet (OVX_C) or a diet with calcium lactate (CaL), with calcium lactate-enriched pumpkin (P_CaL), with calcium lactate and alendronate (CaL_B), or with calcium lactate-enriched pumpkin with alendronate (P_CaL_B). After 12 weeks of the intervention, the rats were sacrificed, and their blood and tissues were collected. The calcium concentrations in serum and in tissues were measured using flame atomic absorption spectrometry (AAS). Serum concentrations of procollagen type-1 amino-terminal propeptide (PINP), parathyroid hormone PTH, estrogen (ES), and osteocalcin (OC) were determined with enzyme-linked immunosorbent assay (ELISA). It was found that enriched pumpkin increased the calcium level in the kidneys (194.13 ± 41.01 mg) compared to the C (87.88 ± 12.42 mg) and OVX_C (79.29 ± 7.66 mg) groups. The addition of alendronate increased the calcium level in the femurs (267.63 ± 23.63 mg) and more than six times in the kidneys (541.33 ± 62.91 mg) compared to the OVX_C group (234.53 ± 21.67 mg and 87.88 ± 12.42 mg, respectively). We found that the CaL, P_CaL, and CaL_B groups had significantly lower PINP serum concentrations (4.45 ± 0.82 ng/mL, 4.14 ± 0.69 ng/mL, and 3.77 ± 0.33 ng/mL) and higher PTH serum levels (3.39 ± 0.54 ng/dL, 3.38 ± 0.57 ng/dL, and 3.47 ± 0.28 ng/dL) than the OVX_C group (4.69 ± 0.82 ng/mL and 2.59 ± 0.45 ng/dL, respectively). In conclusion, pumpkin enriched with calcium lactate affects calcium status and normalizes PINP and PTH serum levels in ovariectomized rats. Diet with enriched pumpkin and alendronate increase calcium concentration in the femur. Enriched pumpkin causes calcium to accumulate in the kidneys of ovariectomized rats; alendronate significantly exacerbates this effect.

Bioactive polysaccharides and oligosaccharides from garlic (Allium sativum L.): Production, physicochemical and biological properties, and structure-function relationships

Garlic is a common food, and many of its biological functions are attributed to its components including functional carbohydrates. Garlic polysaccharides and oligosaccharides as main components are understudied but have future value due to the growing demand for bioactive polysaccharides/oligosaccharides from natural sources. Garlic polysaccharides have molecular weights of 1 × 10³ to 2 × 10⁶  Da, containing small amounts of pectins and fructooligosaccharides and large amounts of inulin-type fructans ((2→1)-linked β-d-Fruf backbones alone or with attached (2→6)-linked β-d-Fruf branched chains). This article provides a detailed review of research progress and identifies knowledge gaps in extraction, production, composition, molecular characteristics, structural features, physicochemical properties, bioactivities, and structure-function relationships of garlic polysaccharides/oligosaccharides. Whether the extraction processes, synthesis approaches, and modification methods established for other non-garlic polysaccharides are also effective for garlic polysaccharides/oligosaccharides (to preserve their desired molecular structures and bioactivities) requires verification. The metabolic processes of ingested garlic polysaccharides/oligosaccharides (as food ingredients/dietary supplements), their modes of action in healthy humans or populations with chronic conditions, and molecular/chain organization-bioactivity relationships remain unclear. Future research directions related to garlic polysaccharides/oligosaccharides are discussed.

Promoting the Calcium-Uptake Bioactivity of Casein Phosphopeptides in vitro and in vivo

Casein phosphopeptides have been studied widely for their ability to chelate calcium. However, systematic studies on the effects of casein phosphopeptides (CPP) on calcium absorption in vitro and in vivo are scarce. The purities of two commercially available products, CPP1 and CPP2, are 18.37 and 25.12%, respectively. Here, the in vitro calcium binding capacity of CPP2 was 142.56 ± 7.39 mg/g, which was higher than that of CPP1 (107.15 ± 6.27 mg/g). The calcium transport results in a Caco-2 monolayer model indicated that, relative to controls, CPP1 and CPP2 increased calcium transport by 21.78 and 53.68%, respectively. Subsequent animal experiments showed that the CPP2-Ca-H group (1% Ca, 0.4% CPP2) had significant increases in the femur index, serum Ca²⁺ and serum osteocalcin levels, and femoral Ca content. The CPP2-Ca-H animal also had decreased serum alkaline phosphatase levels, parathyroid hormone content, and urinary pyridinoline content. Overall, our results demonstrated that CPP2 had stronger effects on promoting calcium uptake than CPP1.

Guava fruit extract and its triterpene constituents have osteoanabolic effect: Stimulation of osteoblast differentiation by activation of mitochondrial respiration via the Wnt/β-catenin signaling

The aim of this study was to evaluate the skeletal effect of guava triterpene-enriched extract (GE) in rats and identify osteogenic compounds thereof, and determine their modes of action. In growing female rats, GE at 250 mg/kg dose increased parameters of peak bone mass including femur length, bone mineral density (BMD) and biomechanical strength, suggesting that GE promoted modeling-directed bone growth. GE also stimulated bone regeneration at the site of bone injury. In adult osteopenic rats (osteopenia induced by ovariectomy, OVX) GE completely restored the lost bones at both axial and appendicular sites, suggesting a strong osteoanabolic effect. Serum metabolomics studies showed changes in several metabolites (some of which are related to bone metabolism) in OVX compared with ovary-intact control and GE treatment to OVX rats reversed those. Out of six abundantly present triterpenes in GE, ursolic acid (UA) and 2α-hydroxy ursolic acid (2α-UA) induced osteogenic differentiation in vitro as did GE by activating Wnt/β-catenin pathway assessed by phosphorylation of GSK-3β. Over-expressing of constitutively active GSK-3β (caGSK-3β) in osteoblasts abolished the differentiation-promoting effect of GE, UA and 2α-UA. All three increased both glycolysis and mitochondrial respiration but only rotenone (inhibitor of mitochondrial electron transfer) and not 2-deoxyglucose (to block glycolysis) inhibited osteoblast differentiation. In addition, caGSK-3β over-expression attenuated the enhanced mitochondrial respiration caused by GE, UA and 2α-UA. We conclude that GE has osteoanabolic effect which is contributed by UA and 2α-UA, and involve activation of canonical Wnt signaling which in turn modulates cellular energy metabolism leading to osteoblast differentiation.

Effect of calcium-binding peptide from Pacific cod (Gadus macrocephalus) bone on calcium bioavailability in rats

Bone collagen peptide with high affinity to Ca was extracted from Pacific cod (Gadus macrocephalus) bone. FTIR spectra of calcium-binding bone collagen peptide showed that band at 3381cm^-1 shifted to 3361cm^-1, 1455cm^-1 moved to 1411cm^-1, and amide II became deeper valley, compared with that of bone collagen peptide. This peptide was sequenced by Q-TOF-MS and sequences of Gly-Pro-Glu-Gly, Gly-Glu-Lys, Gly-Pro-Leu-Gly and Gly-Leu-Pro-Gly appeared repeatedly in some peptides. From SEM, after chelated with calcium, the loose and porous structure turned into granular structure. From the animal experiment, Ca apparent absorption rate, Ca retention rate and femur Ca content of calcium-binding bone collagen peptide group were significantly higher than those of model and CaCO₃ groups (P<0.05), while serum ALP was significantly lower than model group (P<0.05) and similar to control group. The results suggested that calcium-binding bone collagen peptide could improve bioavailability of Ca and thus prevented Ca deficiency.

Inulin: Properties, health benefits and food applications

Inulin is a water soluble storage polysaccharide and belongs to a group of non-digestible carbohydrates called fructans. Inulin has attained the GRAS status in USA and is extensively available in about 36,000 species of plants, amongst, chicory roots are considered as the richest source of inulin. Commonly, inulin is used as a prebiotic, fat replacer, sugar replacer, texture modifier and for the development of functional foods in order to improve health due to its beneficial role in gastric health. This review provides a deep insight about its production, physicochemical properties, role in combating various kinds of metabolic and diet related diseases and utilization as a functional ingredient in novel product development.

Polydextrose Enhances Calcium Absorption and Bone Retention in Ovariectomized Rats

Purpose. To evaluate the effect of polydextrose (PDX) on Ca bioavailability and prevention of loss of bone mass. Methods. Twenty-four two-month-old ovariectomized rats were fed three isocaloric diets only varied in fiber source and content up to 60 days (FOS group, a commercial mixture of short- and long-chain fructooligosaccharide, OVX group fed AIN 93 diet, and PDX group). A SHAM group was included as control. Apparent Ca absorption percentage (%ABS), changes in total skeleton bone mineral content (tsBMC) and bone mineral density (BMD) and femur BMD, % Bone Volume, Ca and organic femur content, caecal weight, and pH were evaluated. Results. %ABS and caecum weight of PDX and FOS were higher, and caecum pH was lower compared to OVX and SHAM. PDX reached a higher pH and lower caecum weight than FOS possibly because PDX is not completely fermented in the colon. Changes in tsBMC and femur BMD in FOS and PDX were significant lower than SHAM but significantly higher than OVX. % Bone Volume and femur % of Ca in PDX were significantly higher than OVX and FOS but lower than SHAM. Conclusions. PDX increased Ca absorption and prevented bone loss in OVX rats.

Gazing into the crystal ball: future considerations for ensuring sustained growth of the functional food and nutraceutical marketplace

Over the last decade the concept of functional foods and nutraceuticals (FFN) has gained support from various stakeholders including the food industry, scientific and academic community, government institutions or regulators, producers and consumers. However, as one begins to evaluate the global FFN industry, several issues emerge including (i) a lack of consensus across jurisdictions for acknowledging safe and efficacious FFN, (ii) challenges regarding the classification of novel food-derived bioactives as FFN or drugs, and (iii) a disconnect between nutrient requirements and dosages of FFN required to facilitate health benefits. The objectives of the present review are to discuss the role of existing stakeholders within the FFN marketplace and identify performance indicators for growth within the FFN sector. In addition, the following report provides feasible resolutions to present and future challenges facing the global FFN industry to ensure sustained long-term growth.

A vision for better health: mass spectrometry imaging for clinical diagnostics

BACKGROUND

Mass spectrometry imaging (MSI) is a powerful tool that grants the ability to investigate a broad mass range of molecules from small molecules to large proteins by creating detailed distribution maps of selected compounds. Its usefulness in biomarker discovery towards clinical applications has obtained success by correlating the molecular expression of tissues acquired from MSI with well-established histology.

RESULTS

To date, MSI has demonstrated its versatility in clinical applications, such as biomarker diagnostics of different diseases, prognostics of disease severities and metabolic response to drug treatment, etc. These studies have provided significant insight in clinical studies over the years and current technical advances are further facilitating the improvement of this field. Although the underlying concept is simple, factors such as choice of ionization method, sample preparation, instrumentation and data analysis must be taken into account for successful applications of MSI. Herein, we briefly reviewed these key elements yet focused on the clinical applications of MSI that cannot be addressed by other means.

CONCLUSIONS

Challenges and future perspectives in this field are also discussed to conclude that the ever-growing applications with continuous development of this powerful analytical tool will lead to a better understanding of the biology of diseases and improvements in clinical diagnostics.

Applications of calcium and its supplement derived from marine organisms

Calcium, being an essential mineral with many important and diversified functions, plays an important role in the health and well being of the human. Marine organisms serve as an alternate source for calcium. Calcium has to be solubilized in the body in order to have the maximum benefits. The increased solubility of calcium from diet contributes to calcium absorption and bioavailability in the body. In this paper, we report various marine sources of calcium, solubilizing the calcium to improve the bioavailability and the applications of calcium as an important mineral in controlling different diseases.

Serum markers of bone turnover are increased by modest weight loss with or without weight-bearing exercise in overweight premenopausal women

Weight loss improves metabolic fitness and reduces morbidity and mortality; however, weight reduction also reduces bone mineral density (BMD) and increases bone turnover. Weight-bearing aerobic exercise may preserve bone mass and maintain normal bone turnover during weight reduction. We investigated the impact of weight-bearing and nonweight-bearing exercise on serum markers of bone formation and breakdown during short-term, modest weight loss in overweight premenopausal women. Subjects (n = 36) were assigned to 1 of 3 weight-loss interventions designed to produce a 5% reduction in body weight over 6 weeks: (i) energy restriction only (n = 11; DIET); (ii) energy restriction plus nonweight-bearing exercise (n = 12, CYCLE); or (iii) energy restriction plus weight-bearing exercise (n = 13, RUN). Bone turnover markers were measured in serum collected at baseline and after weight loss. All groups achieved a ~5% reduction in body weight (DIET = 5.2%; CYCLE = 5.0%; RUN = 4.7%). Osteocalcin (OC) and C-terminal telopeptide of type I collagen (CTX) increased with weight loss in all 3 groups (p < 0.05), whereas bone alkaline phosphatase was unaltered by the weight-loss interventions. At baseline, OC and CTX were positively correlated (r = 0.36, p = 0.03), but the strength of this association was diminished (r = 0.30, p = 0.06) after weight loss. Modest weight loss, regardless of method, resulted in a significant increase in both OC and CTX. Low-impact, weight-bearing exercise had no effect on serum markers of bone formation or resorption in premenopausal women during weight loss. Future studies that examine the effects of high-impact, weight-bearing activity on bone turnover and BMD during weight loss are warranted.

Prolyl-hydroxyproline dipeptide in non-hydrolyzed morning urine and its value in postmenopausal osteoporosis

BACKGROUND

Owing to the high correlation between the level of prolyl-4-hydroxyproline dipeptide in non-hydrolyzed urine and that of 4-hydroxyproline in hydrolyzed urine, we examined whether the dipeptide might function as a valuable marker of bone turnover.

METHODS

Based on densitometric measurements, 68 postmenopausal women were divided into groups of non-osteopathic, osteopenic and osteoporotic subjects. The dipeptide and current urinary resorption markers were assayed in morning urine, the former using liquid chromatography, the others plus serum formation markers by means of immunoassay procedures. Together with the assay of basal levels, diet-related changes and healing effect of yearly alendronate therapy were assessed.

RESULTS

Concentration levels in controls and osteoporotic subjects differed significantly; receiver operating characteristics yielded sensitivity of 0.743, specificity of 0.908, area under curve of 0.903, and cut-off of 10.2 micromol/mmol of creatinine. Spearman rank correlation showed the highest pair coefficient between the dipeptide and osteocalcin. Diet-related changes were not found. Following therapy, a significant decline occurred already within a trimester, whilst with the other resorption markers not until 6 months.

CONCLUSIONS

The ease of the dipeptide assay in non-hydrolyzed urine surpasses that of hydroxyproline, and the results present the compound as a real competition to other commonly assessed markers in osteopathies.

The health benefits of calcium citrate malate: a review of the supporting science

There has been considerable investigation into the health benefits of calcium citrate malate (CCM) since it was first patented in the late 1980s. This chapter is a comprehensive summary of the supporting science and available evidence on the bioavailability and health benefits of consuming CCM. It highlights the important roles that CCM can play during various life stages. CCM has been shown to facilitate calcium retention and bone accrual in children and adolescents. In adults, it effectively promotes the consolidation and maintenance of bone mass. In conjunction with vitamin D, CCM also decreases bone fracture risk in the elderly, slows the rate of bone loss in old age, and is of benefit to the health and well-being of postmenopausal women. CCM is exceptional in that it confers many unique benefits that go beyond bone health. Unlike other calcium sources that necessitate supplementation be in conjunction with a meal to ensure an appreciable benefit is derived, CCM can be consumed with or without food and delivers a significant nutritional benefit to individuals of all ages. The chemistry of CCM makes it a particularly beneficial calcium source for individuals with hypochlorydia or achlorydia, which generally includes the elderly and those on medications that decrease gastric acid secretion. CCM is also recognized as a calcium source that does not increase the risk of kidney stones, and in fact it protects against stone-forming potential. The versatile nature of CCM makes it a convenient and practical calcium salt for use in moist foods and beverages. The major factor that may preclude selection of CCM as a preferred calcium source is the higher cost compared to other sources of calcium commonly used for fortification (e.g., calcium carbonate and tricalcium phosphate). However, formation of CCM directly within beverages or other fluid foods and/or preparations, and the addition of a concentrated CCM solution or slurry, are relatively cost-effective methods by which CCM can be incorporated into finished food and beverage products.

Bone mass and soy isoflavones in socially housed, premenopausal macaques

BACKGROUND

Soy consumption is associated with a lower incidence of hip fracture in Asian than in Western women, an effect often attributed to estrogen-like compounds (isoflavones) in soy. It is not known whether premenopausal soy exposure initiated in adulthood can increase bone mass and thereby reduce fracture risk.

OBJECTIVE

We aimed to determine whether a high-isoflavone soy diet influences bone mass in soy-naïve, premenopausal cynomolgus monkeys (Macaca fascicularis).

DESIGN

Ninety-four skeletally mature females were randomly assigned to consume diets whose protein content came from either high-isoflavone soy or casein and lactalbumin. Animals were socially housed. Bone mass and circulating isoflavone concentrations were measured at baseline and 19 and 31 mo after the start of treatment; bone biomarkers were measured at baseline and 31 mo.

RESULTS

There were no significant differences at any timepoint in whole-body bone mineral content between casein-fed (112.5 +/- 2.1, 119.2 +/- 1.9, and 120.7 +/- 2.1 g) and soy-fed (117.2 +/- 2.1, 122.4 +/- 2.0, and 125.4 +/- 2.3 g; P=0.12) monkeys. Similar results were seen for spinal bone mineral density (casein-fed: 0.46 +/- 0.01, 0.50 +/- 0.01, and 0.52 +/- 0.01 g/cm(2); soy-fed: 0.47 +/- 0.01, 0.51 +/- 0.01, and 0.52 +/- 0.01 g/cm(2); P=0.30) and bone biomarker measurements-bone-specific alkaline phosphatase (soy-fed: 82.3 +/- 4.1 and 63.2 +/- 3.4 ng/mL; casein-fed: 94.1 +/- 4.5 and 61.7 +/- 4.3 ng/mL; P=0.22) and C-terminal crosslink of type 1 collagen (soy-fed: 0.944 +/- 0.06 and 0.89 +/- 0.08 nmol/L; casein-fed: 0.97 +/- 0.07 and 0.78 +/- 0.06 nmol/L; P=0.20).

CONCLUSION

A soy diet high in isoflavones does not significantly affect bone characteristics in initially soy-naïve premenopausal monkeys.

Inulin-type fructans and bone health: state of the art and perspectives in the management of osteoporosis

If the primary role of diet is to provide sufficient nutrients to meet the metabolic requirements of an individual, there is an emerging rationale to support the hypothesis that, by modulating specific target functions in the body, it can help achieve optimal health. Regarding osteoporosis prevention, since Ca is most likely to be inadequate in terms of dietary intake, every strategy targeting an improvement in Ca absorption is very interesting. Actually, this process may be susceptible to manipulation by fermentable substrates. In this light, inulin-type fructans are very interesting, even if we need to gather more data targeting bone metabolism before health professionals can actively advocate their consumption to prevent senile osteoporosis. Besides targeting the prevention of postmenopausal osteoporosis, inulin-type fructans still remain a source for putative innovative dietary health intervention. Indeed, given in combination with isoflavones, they may have a potential for maintaining or improving the bone mass of human subjects, by modulating the bioavailability of phyto-oestrogens.

Inulin, oligofructose and bone health: experimental approaches and mechanisms

Inulin-type fructans have been proposed to benefit mineral retention, thereby enhancing bone health. Many, but not all, experimental animal studies have shown increased mineral absorption by feeding non-digestible oligosaccharides. Possible reasons for inconsistencies are explored.A few studies have reported an enhanced bone mineral density or content. Bone health can be evaluated in chronic feeding studies with bone densitometry, bone breaking strength, bone mineral concentration and bone structure. Isotopic Ca tracers can be used to determine the point of metabolism affected by feeding a functional food ingredient. These methods and the effects of feeding inulin-type fructose are reviewed. Inulin-type fructans enhance Mg retention. Chicory long-chain inulin and oligofructose enhance femoral Ca content, bone mineral density and Ca retention through enhanced Ca absorption and suppressed bone turnover rates, but it is not bone-promoting under all conditions

Dairy proteins and the regulation of satiety and obesity

Over the past decade there has been growing scientific evidence and public acceptance of the role that dietary protein plays in regulation of satiety, feed intake and obesity-related disorders. Dietary protein appears to suppress food intake and delay the return of hunger more than fats or carbohydrates in a manner not due to energy content alone. Also, high-protein diets support the maintenance of muscle mass when subjects reduce their energy intake, ensuring primarily adipose tissue loss. Some protein sources, particularly dairy, contain specific peptides or proteins that may elicit direct effects on satiety. The major proteins present in milk include β-lactalbumin, α-lactoglobulin, immunoglobulins, bovine serum albumin, and the various caseins. In addition, processed whey contains glycomacropeptide, which stimulates pancreatic and gastrointestinal secretion of hormones involved in satiety to a greater extent than whey alone. In the context of the literature, we show that a glycomacropeptide-rich whey protein isolate decreases feed intake and weight gain to a greater extent than a soy protein isolate in obese pigs. Also, insulin sensitivity is improved in pigs consuming high-protein diets, with these effects being independent of protein source. While, high-protein diets may decrease calcium balance and bone strength, it appears that these effects are attenuated by dairy proteins and dairy sources of calcium. These findings suggest that high-protein diets, and in particular those that contain whey proteins, may reduce hunger and food intake, thereby reducing fat deposition and improving insulin sensitivity.

Novel mechanisms of natural antioxidant compounds in biological systems: involvement of glutathione and glutathione-related enzymes

Polyphenols are wide variety of compounds that occur in fruits and vegetables, wine, tea, extra virgin olive oil, chocolate and other cocoa products. Several polyphenols have been demonstrated to have clear antioxidant properties in vitro, and many of their biological actions have been attributed to their intrinsic reducing capabilities. However, this concept appears now to be a simplistic way to conceive their activity. Evidence is indeed accumulating that polyphenols might exert several other specific biological effects that are as yet poorly understood. In this article we review the most recent data on the subject and describe the additional functions that polyphenols can have in biological systems, focusing on their effects on glutathione and its related enzymes. Experimental data indicate that polyhenols may offer an indirect protection by activating endogenous defense systems. Several lines of evidence suggest a tight connection between exogenous and endogenous antioxidants that appear to act in a coordinated fashion. It is reasonable to hypothesize that this is achieved, at least in part, through antioxidant responsive elements (AREs) present in the promoter regions of many of the genes inducible by oxidative and chemical stress. The latest studies strongly suggest that dietary polyphenols can stimulate antioxidant transcription and detoxification defense systems through ARE.

Introducing inulin-type fructans

Inulin is a generic term to cover all beta(2-->1) linear fructans. Chicory inulin is a linear beta(2-->1) fructan (degree of polymerisation (DP) 2 to 60; DPav=12), its partial enzymatic hydrolysis product is oligofructose (DP 2 to 8; DPav=4), and by applying specific separation technologies a long-chain inulin known as inulin HP (DP 10 to 60; DPav=25) can be produced. Finally, a specific product known as oligofructose-enriched inulin is obtained by combining chicory long-chain inulin and oligofructose. Because of the beta-configuration of the anomeric C2 in their fructose monomers, inulin-type fructans resist hydrolysis by intestinal digestive enzymes, they classify as 'non-digestible' carbohydrates, and they are dietary fibres. By increasing faecal biomass and water content of the stools, they improve bowel habits, but they have characteristic features different from other fibres. They affect gastrointestinal functions not because of their physico-chemical properties but rather because of their biochemical and physiological attributes. In the colon, they are rapidly fermented to produce SCFA that are good candidates to explain some of the systemic effects of inulin-type fructans. Fermentation of inulin-type fructans in the large bowel is a selective process; bifidobacteria (and possibly a few other genera) are preferentially stimulated to grow, thus causing significant changes in the composition of the gut microflora by increasing the number of potentially health-promoting bacteria and reducing the number of potentially harmful species. Both oligofructose and inulin are prebiotic. They also induce changes in colonic epithelium stimulating proliferation in the crypts, increasing the concentration of polyamines, changing the profile of mucins, and modulating endocrine as well as immune functions. From a nutrition labelling perspective, inulin-type fructans are not only prebiotic dietary fibres; they are also low-calorie carbohydrates [6.3 kJ/g (1.5 kcal/g)]. Supported by the results of a large number of animal studies and human nutrition intervention trials, the claim 'inulin-type fructans enhance calcium and magnesium absorption' is scientifically substantiated, but different inulin-type fructans have probably a different efficacy (in terms of effective daily dose), the most active product being the oligofructose-enriched inulin. A series of animal studies demonstrate that inulin-type fructans affect the metabolism of lipids primarily by decreasing triglyceridaemia because of a reduction in the number of plasma VLDL particles. The human data largely confirm the animal experiments. They demonstrate mainly a reduction in triglyceridaemia and only a relatively slight decrease in cholesterolaemia mostly in (slightly) hypertriglyceridaemic conditions. Inulin appears thus eligible for an enhanced function claim related to normalization of blood triacylglycerols. A large number of animal data convincingly show that inulin-type fructans reduce the risk of colon carcinogenesis and nutrition intervention trials are now performed to test that hypothesis in human subjects known to be at risk for polyps and cancer development in the large bowel.

One year soy protein supplementation has positive effects on bone formation markers but not bone density in postmenopausal women

BACKGROUND

Although soy protein and its isoflavones have been reported to reduce the risk of osteoporosis in peri- and post-menopausal women, most of these studies are of short duration (i.e. six months). The objective of this study was to examine if one year consumption of soy-containing foods (providing 25 g protein and 60 mg isoflavones) exerts beneficial effects on bone in postmenopausal women.

METHODS

Eighty-seven eligible postmenopausal women were randomly assigned to consume soy or control foods daily for one year. Bone mineral density (BMD) and bone mineral content (BMC) of the whole body, lumbar (L1-L4), and total hip were measured using dual energy x-ray absorptiometry at baseline and after one year. Blood and urine markers of bone metabolism were also assessed.

RESULTS AND DISCUSSION

Sixty-two subjects completed the one-year long study. Whole body and lumbar BMD and BMC were significantly decreased in both the soy and control groups. However, there were no significant changes in total hip BMD and BMC irrespective of treatment. Both treatments positively affected markers of bone formation as indicated by increased serum bone-specific alkaline phosphatase (BSAP) activity, insulin-like growth factor-I (IGF-I), and osteocalcin (BSAP: 27.8 and 25.8%, IGF-I: 12.8 and 26.3%, osteocalcin: 95.2 and 103.4% for control and soy groups, respectively). Neither of the protein supplements had any effect on urinary deoxypyridinoline excretion, a marker of bone resorption.

CONCLUSION

Our findings suggest that although one year supplementation of 25 g protein per se positively modulated markers of bone formation, this amount of protein was unable to prevent lumbar and whole body bone loss in postmenopausal women.

Greek plant extracts exhibit selective estrogen receptor modulator (SERM)-like properties

To prevent bone loss that occurs with increasing age, nutritional and pharmacological factors are needed. Traditional therapeutic agents (selective estrogen receptor modulators or SERMs, biphosphonates, calcitonin) may have serious side effects or contraindications. In an attempt to find food components potentially acting as SERMs, we submitted four plant aqueous extracts derived from Greek flora (Sideritis euboea, Sideritis clandestina, Marticaria chamomilla, and Pimpinella anisum) in a series of in vitro biological assays reflective of SERM profile. We examined their ability (a) to stimulate the differentiation and mineralization of osteoblastic cell culture by histochemical staining for alkaline phosphatase and Alizarin Red-S staining, (b) to induce, like antiestrogens, the insulin growth factor binding protein 3 (IGFBP3) in MCF-7 breast cancer cells, and (c) to proliferate cervical adenocarcinoma (HeLa) cells by use of MTT assay. Our data reveal that all the plant extracts studied at a concentration range 10-100 microg/mL stimulate osteoblastic cell differentiation and exhibit antiestrogenic effect on breast cancer cells without proliferative effects on cervical adenocarcinoma cells. The presence of estradiol inhibited the antiestrogenic effect induced by the extracts on MCF-7 cells, suggesting an estrogen receptor-related mechanism. In conclusion, the aqueous extracts derived from Sideritis euboea, Sideritis clandestina, Marticaria chamomilla, and Pimpinella anisum may form the basis to design "functional foods" for the prevention of osteoporosis.

Phytochemical Research Using Accelerator Mass Spectrometry

Vegetables and fruits provide an array of microchemicals in the form of vitamins and secondary metabolites (phytochemicals) that may lower the risk of chronic disease. Tracing these phytochemicals at physiologic concentrations has been hindered by a lack of quantitative sensitivity for chemically equivalent tracers that could be used safely in healthy people. Accelerator mass spectrometry is a relatively new technique that provides the necessary sensitivity (in attomoles) and measurement precision (<3%) towards 14C-labeled phytochemicals for detailed kinetic studies in humans at dietary levels.

Techniques: The application of accelerator mass spectrometry to pharmacology and toxicology

The exquisite sensitivity of accelerator mass spectrometry (AMS) is being used in biomedical applications to quantitate many isotopes, including 14C, 3H, 41Ca and 27Al, at attomole (10(-18)) concentrations. This enables compounds and metabolites to be measured in human urine and plasma after administration of low pharmacologically or toxicologically relevant doses of labelled chemicals and drugs. The detection of modified proteins or DNA in target organs after dosing with potential carcinogens has also been achieved in many studies. Advances aimed at increasing sample throughput and expanding applications by coupling AMS instruments directly to chromatographic separation systems are currently underway.

Evaluation of microdosing strategies for studies in preclinical drug development: demonstration of linear pharmacokinetics in dogs of a nucleoside analog over a 50-fold dose range

The technique of accelerator mass spectrometry (AMS) was validated successfully and used to study the pharmacokinetics and disposition in dogs of a preclinical drug candidate (7-deaza-2'-C-methyl-adenosine; Compound A), after oral and intravenous administration. The primary objective of this study was to examine whether Compound A displayed linear kinetics across subpharmacological (microdose) and pharmacological dose ranges in an animal model, before initiation of a human microdose study. The AMS-derived disposition properties of Compound A were comparable to data obtained via conventional techniques such as liquid chromatography-tandem mass spectrometry and liquid scintillation counting analyses. Compound A displayed multiphasic kinetics and exhibited low plasma clearance (5.8 ml/min/kg), a long terminal elimination half-life (17.5 h), and high oral bioavailability (103%). Currently, there are no published comparisons of the kinetics of a pharmaceutical compound at pharmacological versus subpharmacological doses using microdosing strategies. The present study thus provides the first description of the full pharmacokinetic profile of a drug candidate assessed under these two dosing regimens. The data demonstrated that the pharmacokinetic properties of Compound A following dosing at 0.02 mg/kg were similar to those at 1 mg/kg, indicating that in the case of Compound A, the pharmacokinetics in the dog appear to be linear across this 50-fold dose range. Moreover, the exceptional sensitivity of AMS provided a pharmacokinetic profile of Compound A, even after a microdose, which revealed aspects of the disposition of this agent that were inaccessible by conventional techniques.