Cardiovascular disease-risk factors in middle-aged osteopaenic women treated with calcium alone or combined to three nutrients essential to artery and bone collagen.

BACKGROUND: Recent research suggests that cardiovascular disease (CVD) and bone loss are functionally interwoven. This study examined the concomitant effects of a nutritional treatment of osteopaenia on CVD-risk factors. METHODS: A 1-year placebo-controlled trial was conducted on middle-aged women with normal (group A) or low (groups B and C) bone mineral density. Subjects (n = 20 per group) took daily either a placebo, calcium carbonate alone or combined to a vitamin (C and B(6))-proline capsule, respectively. Urinary pyridoxic acid (used to assess treatment compliance), plasma homocysteine, serum lipids and lipoproteins were measured before and after nutritional intervention. RESULTS: Groups were comparable at baseline in most parameters of interest. No changes occurred in groups A and B. The 4%, 7% and 25% reductions of total cholesterol, LDL and triglycerides, and 14% elevation of HDL were all significant in group C. A trend toward reduction was observed for homocysteine in this group. CONCLUSIONS: Vitamins C (500 mg) and B(6) (75 mg) combined with proline had consistent beneficial effects on CVD-risk factors, whereas calcium alone did not. This study also underlined the importance of considering vitamin B(6) status as a potential CVD risk factor.

Elevation of plasma homocysteine in natural menopause can not be explained by a lack of vitamin coenzyme availability: relevance to the risk of cardiovascular disease.

UNLABELLED: The risk of cardio vascular disease (CVD) doubles after menopause. Plasma homocysteine (hCy) is a risk factor which is influenced by vitamins B12,B6 and folate. The present study was conducted to examine the relationship of plasma hCy to the three vitamins and other contributing variables in early natural menopause. METHODS: Participants were healthy, non smoking Caucasian women 3 to 5 years postmenopausal (n = 26) or premenopausal between 30 and 45 y(n = 30). Anthropometric data, dietary records and plasma concentrations of hCy, vitamin B6, vitamin B12 and folate were obtained. RESULTS: The nutritional status of vitamins B6, B12 and folate as measured by dietary intake and blood concentrations was adequate in both groups. Mean fasting plasma total (t) hCy concentration of postmenopausal group was 2-fold higher than the value found for control group (P < 0.0001) without oral methionine loading. The difference between the two groups remained highly significant after adjustment for confounding variables by multivariate analysis, suggesting that the effect of estrogen deficiency was direct. CONCLUSION: In addition to the loss of the protective effects of estrogen on their cardiovascular physiology and lipid metabolism, postmenopausal women are exposed to higher plasma hCy concentrations and deleterious cardiovascular effects. The exact mechanism is not known but does not seem to be related to coenzyme deficiency.

Pyridoxine deficiency affects biomechanical properties of chick tibial bone.

The mechanical integrity of bone is dependent on the bone matrix, which is believed to account for the plastic deformation of the tissue, and the mineral, which is believed to account for the elastic deformation. The validity of this model is shown in this study based on analysis of the bones of vitamin B6-deficient and vitamin B6-replete chick bones. In this model, when B6-deficient and control animals are compared, vitamin B6 deficiency has no effect on the mineral content or composition of cortical bone as measured by ash weight (63 +/- 6 vs. 58 +/- 3); mineral to matrix ratio of the FTIR spectra (4.2 +/- 0.6 vs. 4.5 +/- 0.2), line-broadening analyses of the X-ray diffraction 002 peak (beta 002 = 0.50 +/- 0.1 vs. 0.49 +/- 0.01), or other features of the infrared spectra. In contrast, collagen was significantly more extractable from vitamin B6-deficient chick bones (20 +/- 2% of total hydroxyproline extracted vs. 10 +/- 3% p < or = 0.001). The B6-deficient bones also contained an increased amount of the reducible cross-links DHLNL, dehydro-dihydroxylysinonorleucine, (1.03 +/- 0.07 vs. 0.84 +/- 0.13 p < or = 0.001); and a nonsignificant increase in HLNL, dehydro-hydroxylysinonorleucine, (0.51 +/- 0.03 vs. 0.43 +/- 0.03, p < or = 0.10). There were no significant changes in bone length, bone diameter, or area moment of inertia. In four-point bending, no significant changes in elastic modulus, stiffness, offset yield deflection, or fracture deflection were detected. However, fracture load in the B6-deficient animals was decreased from 203 +/- 35 MPa to 151 +/- 23 MPa, p < or = 0.01, and offset yield load was decreased from 165 +/- 9 MPa to 125 +/- 14 MPa, p < or = 0.05. Since earlier histomorphometric studies had demonstrated that the B6-deficient bones were osteopenic, these data suggest that although proper cortical bone mineralization occurred, the alterations of the collagen resulted in changes to bone mechanical performance.

Long-term effect of low-dose combined steroid contraceptives on body iron status.

The present study was aimed to evaluate iron metabolism in active and healthy adult women having taken oral contraceptives (OC) long-term. Mean dietary iron intake in age-matched control and experimental groups was adequate. Serum ferritin used as a marker for body iron stores was marginal in both groups underlying a high prevalence of deficient-iron reserves among subjects. This parameter was not correlated to the iron content of the diet. The serum iron concentration was significantly higher in OC users than control subjects (p less than 0.001). Biochemical results commanded a discussion on the pertinence of evaluating the total dietary iron intake and on the sensitivity of biochemical methods used to assess the iron status.

Loss of decorin from the surface zone of articular cartilage in a chick model of osteoarthritis.

The objective of this study was to immunolocalize decorin and to assess changes as a result of pyridoxine (PN) deficiency in chick articular cartilage from femoral condyles. After maintenance on a normal diet for the first two weeks after hatching, 15 broiler chickens were deprived of this vitamin for 6 weeks. It was previously shown that the ankle joints of PN-deficient animals are swollen with effusions. They also present an abnormal gait, enlarged bony margins, and fissuring of the articular cartilages. Milder changes (no fissures) were also shown in the knee joints. Data from a previous study were suggestive that sulfated glycosaminoglycans are lost from the knee cartilage surface into synovial fluid. The current study was focused on the small proteoglycan, decorin, which coats the surface of collagen fibrils and may regulate their morphology. To examine decorin in normal and PN-deficient articular cartilage, a monoclonal antibody to an epitope on the protein core of decorin was used for immunohistochemical staining of tissue sections and for Western Blot analysis of cartilage extracts. Reduction of staining with the antibody was demonstrated in the tangential surface zone of PN-deficient cartilage, and Western Blot analysis showed reduced intensity of decorin bands compared to normal controls. These data suggest that a lack of decorin may play a role in the enlargement of collagen bundles in the tangential zone of PN-deficient articular cartilage as observed in a previous electron microscopic study.

Effects of modifying dietary protein in the presence and absence of vitamin B6, on the regulation of plasma calcium and phosphorus levels--positive impact of yeast Saccharomyces cerevisiae.

Vitamin B6 status has been assessed according to the activation coefficient (AC) of plasma aspartic aminotransferase (AST) activity. Fast-growing male one-day-old broiler chicks, divided into two groups (supplemented with pyridoxine or not), were fed a soy protein isolate (Soyamin) or a purified amino acid diet containing or not Saccharomyces cerevisiae yeast (2%), primarily used to promote the growth of the B6-deficient animals. In one experiment, the protein level of the diet has been increased to augment the metabolic demand for PN. The B6-deficient Soyamin diet B containing yeast produced a mild deficiency (without incidence of morbidity and mortality) and the deficiency was severe (appearance of neurological symptoms after 10 days, AC 1.5) when yeast was deleted (diet A). The inclusion of yeast in both Soyamin and amino acid diets significantly increased plasma Ca and Pi levels (p < 0.001) whereas increasing the protein intake (diet C) had an inverse effect, reflecting an inhibitory effect on intestinal absorption of these minerals. Changes in plasma Ca and Pi levels due to dietary treatments were summarized in terms of their theoretical ion product. The amino acid diet D produced the lowest Ca x Pi ion product and the highest value was obtained with the yeast-containing diets B and E, regardless of the vitamin B6 intake and the dietary protein source. Plasma Ca and Pi levels were simultaneously elevated in severe vitamin B6 deficiency (diet A) as compared to control group (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Nutritional and psychological status of young women after a short-term use of a triphasic contraceptive steroid preparation.

The present study was aimed to assess the psychological status of young healthy women after the administration of a triphasic contraceptive steroid preparation for six complete menstrual cycles. Subjects had never used oral contraceptives (OC) and had neither a familial history of depression nor psychological disturbances. OC-induced psychological disturbances were interpreted for years as evidence of pyridoxine (vitamin B6) deficiency. Other nutritional deficiencies, namely in cobalamin, folate and iron, can disturb the functioning of the central nervous system. In addition, a deficiency of any of these nutrients can lead to several anemia-induced symptoms that are highly susceptible to influence the psychological status. For ample evidence, nutritional status was then evaluated in parallel to psychological testing. Blood iron and vitamin levels of interest were found to be adequate and could not have biased the response to a psychological test (MMPI). This study showed that a 6-month Triphasil treatment did not modify significantly the psychological status of subjects. To our knowledge, this is the first psychological study on young never OC-users taking an identical triphasic contraceptive steroid preparation to investigate early psychological side-effects due to OC, at a similar time of the menstrual cycle, when nutritional status was also evaluated.

Early effect of a low dose (30 micrograms) ethinyl estradiol-containing Triphasil on vitamin B6 status. A follow-up study on six menstrual cycles.

The objectives of the study were to follow-up six artificial menstrual cycles induced by Triphasil in order to determine: 1) the time of apparition of B6 metabolic side-effects, in the eventuality they occur, and 2) the existence or non-existence of a normalization process and if so, when it is initiated. The choice of this triphasic OC preparation was based on its current popularity among modern gynecologists. Among the selected twenty-three young women who had never used oral contraceptives (OC), fourteen consented to try a new contraceptive method. Their nutritional status including anthropometric, hematologic, biochemical and dietetic (including vitamin B6 intake) parameters was found to be adequate. A functional enzymatic test coupled to a direct measurement of vitamin B6 was employed to obtain a complete assessment of their vitamin B6 status. By using both approaches, only one case (7%) of deficiency due to OC was evidenced. This well-controlled study revealed that a short-term use of a relatively low dose estrogen-containing OC (30 micrograms) did not alter PLP concentrations in plasma and erythrocytes in the majority of our young subjects consuming adequate diets. However, a disturbance in vitamin B6 metabolism was detected. PL levels in both blood components have increased steadily and did not subside to pretreatment values at the end of the experiment. In conclusion, the single use of the PLP vitamer can be misleading as demonstrated by other investigators. To assess B6-status during oral contraception, in addition to a functional enzymatic test, it may be necessary to include the other aldehydic form of vitamin B6, to fully establish and comprehend hormone-induced adverse effects on this metabolism, particularly those of progesterone/progestin that have not yet been explored.

Effects of dietary proteins and yeast Saccharomyces cerevisiae on vitamin B6 status during growth.

Male rapidly growing broiler chicks were fed a moderate (22%) or a high protein (30%) well-balanced diet containing yeast Saccharomyces cerevisiae (2%) and consisting of soy protein isolate (Soyamin) or a purified amino acid mixture. The vitamin B6 status was assessed according to the in vitro stimulated activity of aspartic aminotransferase (activation coefficient; AC) and pyridoxal phosphate concentrations in plasma and erythrocytes. No weight difference was found between age-matched control and B6-deficient animals fed the Soyamin diet containing yeast. None of the deficient animals presented signs of malfunctions of the central nervous system. These animals grew well and their skeletal development was normal after 6 weeks of age. Due to the presence of yeast, increasing dietary protein intake did not augment the metabolic requirement for pyridoxine. The removal of yeast from the Soyamin diet provoked a severe symptomatic deficiency (AC 1.5). It seemed that yeast did more than promoting growth. It also protected against a lack of vitamin B6: feed utilization was not impaired. The present study showed that a low level of 0.6 mg vitamin B6/kg in a corn-Soyamin diet containing yeast was adequate to maintain normal growth and to avoid neurological symptoms. The pyridoxine requirement for normal growth and absence of convulsions has been reported to be approximately 3 mg/kg diet.

Aspartate aminotransferase activity in experimentally induced asymptomatic vitamin B6 deficiency in chicks.

Forty-five male Lohmann chicks were grown up to 6 weeks of age. The experimental diet containing a high protein level (30%) was aimed at increasing the metabolic need for PN. Microbiological analysis on the basal ration revealed a marginal content of 4.7 mumol PN/kg. The vitamin B6 status was assessed at the end of the experiment according to the basal activity of aspartate aminotransferase (AspAT) in plasma and in erythrocytes, and the in vitro stimulated activity with pyridoxal 5'-phosphate (PLP). None of the deficient chicks had any clinical signs attributable to malfunction of the nervous system, and they grew as well as those receiving the control diet. Vitamin B6 deficiency was biochemically confirmed by a significant depression of AspAT activity in plasma (p less than 0.001) and in erythrocytes (p less than 0.01). The addition of PLP in vitro enhanced the catalytic activity of the plasma enzyme, but had negligible effect on the erythrocyte enzyme. The degree of stimulation in vitro of the apoenzyme of AspAT not only depends on the endogenous vitamin B6 content, but also on the basal activity of the enzyme. A 15-day repletion period with a daily oral dose (50 mumol PN) did not result in a complete restoration of the enzyme activity, indicating that the availability of apoenzyme had been curtailed. This experiment demonstrated that chicks fed a high protein corn-soyamin diet with a limited amount of PN but containing Saccharomyces yeast showed no nervous signs or perosis, but significant metabolic disturbances.(ABSTRACT TRUNCATED AT 250 WORDS)

Dietary macro- and micronutrient intakes of nonsupplemented pre- and postmenopausal women with a perspective on menopause-associated diseases.

OBJECTIVES: To assess the dietary intakes and diet quality of menopausal women relative to premenopausal women, and to determine whether their diets are compatible with reducing risks of cardiovascular disease (CVD) and osteoporosis. DESIGN: Cross-sectional study using 3-day food records and anthropometric measurements. Subjects Thirty apparently healthy, nonoestrogen using and nonsupplemented women menopausal since 3-5 years and 30 well-matched premenopausal women. Outcome measures Nutrient intakes, diet nutrient density, body mass index (BMI), waist circumference, waist-to-hip ratio and serum oestradiol. RESULTS: Energy intake and body weight of pre- and postmenopausal women were comparable. Their BMI, waist circumference and waist-to-hip ratios were within healthy ranges. The diet of postmenopausal women was compatible (less total lipids and saturated fatty acids; more fibres, antioxidant vitamins and potassium) with North American nutritional recommendations linked to cardiovascular health. Their dietary iron intakes exceeded their reduced physiological need, which may jeopardize their cardiovascular system. Their calcium and vitamin D intakes were far below recommendations for healthy bones. Five other nutrients were also suboptimal. Phosphorus intake (high in both groups) correlated with dietary proteins, sulphur amino acids and calcium. CONCLUSIONS: The diet of the postmenopausal women studied were more compatible with national nutritional recommendations than that of premenopausal controls. However, these postmenopausal women, not taking hormone replacement therapy (HRT) and having inadequate dietary calcium and vitamin D intakes, may be at increased risk of osteoporotic fracture later in life. More studies on CVD risk inherent to body iron accumulation involving a large number of postmenopausal women are warranted before planning public health measures regarding dietary iron intake.

Vitamin B6 deficiency experimentally-induced bone and joint disorder: microscopic, radiographic and biochemical evidence.

In the present study the effect of pyridoxine deficiency on the ultrastructure and morphology of bone and its metabolism was examined in the rapidly growing chick. Pyridoxine-deficient animals had tibias of reduced dry weight and cortical thickness. Histomorphometry demonstrated a disproportionately high eroded surface, lower amount of osteoid tissue and reduced mineralized trabecular width. Anterior-posterior radiographs of the tibiotarsometatarsal joint showed reduced secondary ossification centres and coarse trabeculation. Decalcified metaphyseal cartilage showed irregular trabeculas and a markedly reduced amount of Fast-green counterstain matrix suggesting that there is less collagen present and in turn less availability for matrix to be laid down for later calcification. Plasma activity of the bone alkaline phosphatase isoenzyme (EC 3.1.3.1) was decreased. Plasma Ca and PO4 levels did not vary. The present bone study referring to a pseudo-lathyritic state in which collagen maturation is not completely achieved supports the hypothesis that pyridoxine is an essential nutrient for the connective tissue matrix.

Testing the tyrosine/catecholamine hypothesis of oral contraceptive-induced psychological side-effects: a controlled study on triphasil.

BACKGROUND: This study was conducted to probe the existence of oral contraceptive (OC)-induced psychological side effects that might be undetectable by psychometric testing. METHODS: Triphasil was administered during six complete menstrual cycles to young never-OC-users. Plasma Tyr and Trp/Sigma-respective competitor neutral amino acids (NAA) ratio and concentrations of other amino acids (AA), known to be involved in the functioning of the central nervous system (CNS) and the synthesis of neurotransmitters, in particular, were used as biochemical markers to assess this likelihood. Factors known to influence plasma AA concentrations such as cortisol and pyridoxal phosphate (PLP, active form of vitamin B6), both modulators of AA intestinal absorption, were examined. RESULTS: Dietary supply of amino acid substrates (precursors) and blood levels of coenzyme/cofactor (vitamin B6 and iron) involved were adequate in both groups and were kept constant throughout the treatment. The rise in plasma cortisol, known to be stimulated under the action of estrogen, was significant (p < 0.05) after the first menstrual cycle and remained higher (although not significantly) than mean baseline and reference normal values at the end of the 6-month OC treatment. Plasma Trp/Sigma-specific competitor NAA ratio remained unchanged whereas Tyr/Sigma-specific competitor NAA ratio was significantly (p < 0.02) reduced after the sixth artificial menstrual cycle. CONCLUSION: Although plasma AA biochemical markers cannot accurately assess CNS activity, they seem to be more sensitive than a comprehensive psychometric testing (MMPI) in assessing OC-induced psychological changes.

Morphological abnormalities in vitamin B6 deficient tarsometatarsal chick cartilage.

The aim of this study was to test the hypothesis that deficiency of vitamin B6 would produce morphological characteristics of osteochondral lathyrism. To accomplish this goal, morphological characteristics of chick cartilage in which lathyrism was produced by two separate dietary regimens was compared to morphological changes encountered in vitamin B6 deficiency. Vitamin B6 deficiency should reduce activity of lysyloxidase needed for producing intermolecular cross-links. The question to be addressed was: would this latter deficiency impair collagen morphological features and secondarily other structures indirectly by reducing collagen molecular assembly? Failure of cross-linking of collagen in the positive controls was related to a lack of functional aldehyde cross-link intermediates which are blocked by homocysteine and aminoacetonitrile. Day-old-male Lohmann chicks were fed adequate (6 mg/kg) or vitamin B6-deficient diets. Cross-link defects were induced by homocysteine-rich diets (0.6% w/w) or a diet containing aminoacetonitrile (0.1% w/w). Animals were sacrificed at 6 weeks of age and Ossa tarsalia articular cartilage specimens, as well as the proximal end of tarsometatarsus were dissected from the tibial metatarsal joint, a major weight-bearing site. Light microscopic observations revealed reduction of subarticular trabecular bone formation, concurrent with overexpansion of the hypertrophic cell zone. Ultrastructural electron microscopy observation of articular fibro-cartilage indicated significant thickening of collagen fibers in vitamin B6 deficient birds, as well as the positive controls in comparison to that of cage-matched control birds. It was concluded that vitamin B6 deficient cross-linking may be responsible for the observed delay in bone development and aforementioned cartilage histological alterations.

Connective tissue integrity is lost in vitamin B-6-deficient chicks.

The objective of the present investigation was to characterize further the connective tissue disorder produced by pyridoxine (vitamin B-6) deficiency, as previously evidenced by electron microscopy. Following the second post-natal week, fast growing male chicks were deprived of pyridoxine for a 1-mo period. Six weeks post-natally, blood concentrations in the experimental deficiency group had declined to deficiency levels as registered by low concentrations of pyridoxal phosphate (coenzyme form) in erythrocytes, but did not reach levels associated with neurological symptoms. Light microscopic study showed abnormalities in the extracellular matrix of the connective tissues. Collagen cross-links and the aldehyde contents were not significantly lower in cartilage and tendon collagens of vitamin B-6-deficient animals than in age-matched controls; also, their proteoglycan degrading protease and collagenase activities measured in articular cartilages were not greater. Thus, proteolysis was an unlikely alternative mechanism to account for the loss of connective tissue integrity. These results point to the need for further investigation into adhesive properties of collagen associated proteoglycans or other proteins in vitamin B-6-deficient connective tissue.

A cartilage matrix deficiency experimentally induced by vitamin B6 deficiency.

A vitamin B6-deficiency-induced disorder in avian articular cartilage resembling osteoarthritis has been further characterized. We measured several parameters of proteoglycan (PG) metabolism, i.e., fixed charge density and sulfated glycosaminoglycans (S-GAG) content in PN-deficient versus control articular cartilage and synovial fluid from the knee joint. Statistically significant changes were: 1) decreased content and increased extractability of total sulfated PGs from articular cartilage with guanidine HCl; 2) elevation of S-GAG concentration in synovial fluid; 3) increased plasma cystathionine (sulfur amino acid) levels. PG synthesis as assessed by 35SO4 incorporation into S-GAGs was not impaired. A lack of cartilage swelling in 0.15 M saline and the normal water content indicated that although disturbed, the collagen network was not disrupted. This finding was in agreement with a previous microscopic study that revealed no fissures in the articular cartilage. Previous findings of a normal aggregating PG size-distribution and absence of elevated metalloproteases made a disturbance of aggregating PG metabolism unlikely. Escape into the synovial fluid of small PGs, normally bound to articular collagen, was believed to result from an alteration in collagen molecular organization that could be secondary to elevated circulating SH-compounds.

Perturbations in factors that modulate osteoblast functions in vitamin B6 deficiency.

It was hypothesized that the widespread structural defect of collagen in connective tissue of vitamin B6 deficient-animals and the consequent alteration in bone biomechanical properties cause an additional stress to their inflamed swollen tibiotarsometatarsal joints. The present study showed a 32% elevation (P < 0.02) in mean plasma free cortisol concentration. Vitamin D metabolism was impaired but without changing plasma calcium homeostasis and bone mineral content. Mean plasma calcitriol [1,25(OH)2D] concentration was significantly reduced (P < 0.001). Because plasma calcidiol concentration did not change, we speculated that either renal 25-hydroxycalciferol-1alpha-hydroxylase activity was reduced or 1,25(OH)2D turnover was increased. Plasma osteocalcin, an index of osteoblast function related to bone formation, was significantly decreased (P < 0.05). This adverse effect on osteoblasts was consistent with the reduction of bone specific alkaline phosphatase activity (another index of bone formation) found in a previous study. The excess of cortisol may have impaired these bone cells functions directly and (or) indirectly via the decline in calcitriol synthesis. Plasma hydroxyproline concentrations in B6-deficient animals were found to be significantly reduced (P < 0.001), suggesting that cortisol in excess had also a suppressive effect on another hydroxylase, namely tissue (mainly bone and liver) prolyl hydroxylase. The bone uncoupling (in formation and resorption) associated with vitamin B6 deficiency seems to be due to secondary hypercortisolism and (or) another unknown factors but not related to a change in bone modulators such as IGF-1 and eicosanoids.