[Disorders of calcium metabolism]

The majority of clinical complaints derive from disorders of calcium metabolism and are associated with a wide variety of clinical symptoms caused by numerous diseases with entirely different types of pathophysiology. The prognosis varies from favorable to fatal depending on the pathophysiology of the underlying disorder of calcium metabolism; therefore, the diagnostic work-up aims to quickly identify the underlying disease causing the disturbance in calcium homeostasis. Every clinical situation with a diminished state of calcium absorption is treated with calcium and vitamin D in varying doses whereas every disorder with an increased calcium absorptive or resorptive state is treated with improved diuresis in addition to antiresorptive drugs, such as bisphosphonates. In many situations the management of a disturbed calcium balance requires an interdisciplinary approach in order to treat the underlying disease in parallel with correction of the calcium homeostasis.

Mediterranean diet pyramid: a proposal for Italian people

Bread was a staple in the traditional Mediterranean diet of the early 1960s, as well as nowadays; however, it was a stone ground sourdough bread in Nicotera and probably in the Greek cohorts of the Seven Countries Study. In the present review, the nutritional characteristics of this food are analyzed in relation to its protective effects on coronary heart disease, metabolic diseases and cancer. According to our traditions, cultural heritage and scientific evidence, we propose that only cereal foods with low glycemic index (GI) and rich in fiber have to be placed at the base of the Mediterranean diet pyramid, whereas refined grains and high GI starchy foods have to be sited at the top.

Nutritional iron turned inside out: intestinal stress from a gut microbial perspective

Iron is abundantly present on earth, essential for most microorganisms and crucial for human health. Human iron deficiency that is nevertheless highly prevalent in developing regions of the world can be effectively treated by oral iron administration. Accumulating evidence indicates that excess of unabsorbed iron that enters the colonic lumen causes unwanted side effects at the intestinal host-microbiota interface. The chemical properties of iron, the luminal environment and host iron withdrawal mechanisms, especially during inflammation, can turn the intestine in a rather stressful milieu. Certain pathogenic enteric bacteria can, however, deal with this stress at the expense of other members of the gut microbiota, while their virulence also seems to be stimulated in an iron-rich intestinal environment. This review covers the multifaceted aspects of nutritional iron stress with respect to growth, composition, metabolism and pathogenicity of the gut microbiota in relation to human health. We aim to present an unpreceded view on the dynamic effects and impact of oral iron administration on intestinal host-microbiota interactions to provide leads for future research and other applications.

Combating Mineral Malnutrition through Iron and Zinc Biofortification of Cereals

 Iron and zinc are 2 important nutrients in the human diet. Their deficiencies in humans lead to a variety of health-related problems. Iron and zinc biofortification of cereals is considered a cost-effective solution to overcome the malnutrition of these minerals. Biofortification aims at either increasing accumulation of these minerals in edible parts, endosperm, or to increase their bioavailability. Iron and zinc fertilization management positively influence their accumulation in cereal grains. Regarding genetic strategies, quantitative genetic studies show the existence of ample variation for iron and zinc accumulation as well as inhibitors or promoters of their bioavailability in cereal grains. However, the genes underlying this variation have rarely been identified and never used in breeding programs. Genetically modified cereals developed by modulation of genes involved in iron and zinc homeostasis, or genes influencing bioavailability, have shown promising results. However, iron and zinc concentration were quantified in the whole grains during most of the studies, whereas a significant proportion of them is lost during milling. This makes it difficult to realistically assess the effectiveness of the different strategies. Moreover, modifications in the accumulation of toxic elements, like cadmium and arsenic, that are of concern for food safety are rarely determined. Trials in living organisms with iron- and zinc-biofortified cereals also remain to be undertaken. This review focuses on the common challenges and their possible solutions related to agronomic as well as genetic iron and zinc biofortification of cereals.

Lupin protein isolate versus casein modifies cholesterol excretion and mRNA expression of intestinal sterol transporters in a pig model

Background

Lupin proteins exert hypocholesterolemic effects in man and animals, although the underlying mechanism remains uncertain. Herein we investigated whether lupin proteins compared to casein modulate sterol excretion and mRNA expression of intestinal sterol transporters by use of pigs as an animal model with similar lipid metabolism as humans, and cellular cholesterol-uptake by Caco-2 cells.

Methods

Two groups of pigs were fed cholesterol-containing diets with either 230 g/kg of lupin protein isolate from L. angustifolius or 230 g/kg casein, for 4 weeks. Faeces were collected quantitatively over a 5 d period for analysis of neutral sterols and bile acids by gas chromatographically methods. The mRNA abundances of intestinal lipid transporters were analysed by real-time RT-PCR. Cholesterol-uptake studies were performed with Caco-2 cells that were incubated with lupin conglutin γ, phytate, ezetimibe or albumin in the presence of labelled [4-¹⁴C]-cholesterol.

Results

Pigs fed the lupin protein isolate revealed lower cholesterol concentrations in total plasma, LDL and HDL than pigs fed casein (P < 0.05). Analysis of faeces revealed a higher output of cholesterol in pigs that were fed lupin protein isolate compared to pigs that received casein (+57.1%; P < 0.05). Relative mRNA concentrations of intestinal sterol transporters involved in cholesterol absorption (Niemann-Pick C1-like 1, scavenger receptor class B, type 1) were lower in pigs fed lupin protein isolate than in those who received casein (P < 0.05). In vitro data showed that phytate was capable of reducing the uptake of labelled [4-¹⁴C]-cholesterol into the Caco-2 cells to the same extend as ezetimibe when compared to control (−20.5% vs. −21.1%; P < 0.05).

Conclusions

Data reveal that the cholesterol-lowering effect of lupin protein isolate is attributable to an increased faecal output of cholesterol and a reduced intestinal uptake of cholesterol. The findings indicate phytate as a possible biofunctional ingredient of lupin protein isolate.

Distribution and speciation of iron and zinc in grain of two wheat genotypes

This study aimed to determine differences among wheat cultivars in the distribution and speciation of Fe and Zn in grain milling fractions. Cultivars with higher Fe and Zn concentrations in the wholemeal flour were found to contain higher concentrations in the white flour. Soluble Fe and Zn were extracted and analyzed by size exclusion-inductively coupled plasma mass spectrometry. Fe speciation varied between milling fractions with a low molecular weight (LMW) complex likely to be Fe-deoxymugenic acid/nicotianamine being the predominant extractable Fe species in white flour, accounting for approximately 85% of the extractable Fe. Bran fractions had a lower amount of LMW-Fe form but more as soluble Fe-phytate and an unidentified high molecular weight peak. In the white flour fraction soluble Zn was found to be present mainly as a LMW peak likely to be Zn-nicotianamine complex. Soluble Fe-phytate was found in the white flour fraction of a high-Fe cultivar but not in a low-Fe cultivar.

A tetranaphthoimidazolium receptor as a fluorescent chemosensor for phytate

A new tetranaphthoimidazolium receptor showed a selective fluorescence enhancement with phytate, myo-inositol hexakisphosphate (IP₆), in 100% aqueous solution at pH 7.4.

Bioavailability of iron, zinc, folic acid, and vitamin A from fortified maize

Several strategies appear suitable to improve iron and zinc bioavailability from fortified maize, and fortification per se will increase the intake of bioavailable iron and zinc. Corn masa flour or whole maize should be fortified with sodium iron ethylenediaminetetraacetate (NaFeEDTA), ferrous fumarate, or ferrous sulfate, and degermed corn flour should be fortified with ferrous sulfate or ferrous fumarate. The choice of zinc fortificant appears to have a limited impact on zinc bioavailability. Phytic acid is a major inhibitor of both iron and zinc absorption. Degermination at the mill will reduce phytic acid content, and degermed maize appears to be a suitable vehicle for iron and zinc fortification. Enzymatic phytate degradation may be a suitable home-based technique to enhance the bioavailability of iron and zinc from fortified maize. Bioavailability experiments with low phytic acid-containing maize varieties have suggested an improved zinc bioavailability compared to wild-type counterparts. The bioavailability of folic acid from maize porridge was reported to be slightly higher than from baked wheat bread. The bioavailability of vitamin A provided as encapsulated retinyl esters is generally high and is typically not strongly influenced by the food matrix, but has not been fully investigated in maize.

Dietary and pharmacological modification of fibroblast growth factor-23 in chronic kidney disease

Increased levels of phosphorus and fibroblast growth factor-23 (FGF-23) are strong predictors of cardiovascular morbidity and mortality. From a physiological perspective and supported by some data, phosphorus is the main driver for FGF-23 secretion. Therefore, it is conceivable that interventions aiming at restriction of phosphorus uptake from the gastrointestinal tract may lower serum FGF-23 levels and improve cardiovascular risk and subsequently survival. It is not currently known to what extend phosphorus and FGF-23 are independent risk factors, and therefore both need to be targeted. However, their respective metabolisms are tightly connected. Control of phosphorus levels in chronic kidney disease (CKD) patients is attempted mainly by restriction of dietary intake and the use of phosphorus binders. In this review, it is outlined that not just the amount of dietary phosphorus intake is important but also its type (organic vs. inorganic), its source (animal vs. plant derived), and the protein-to-phosphorus ratio in the bioavailability of phosphorus from food. This qualitative aspect of diet is likely a neglected aspect of dietary counseling in CKD. However, in more advanced stages of CKD, dietary restriction of phosphorus alone is usually not sufficient to control hyperphosphatemia, and phosphorus binders are indicated. The inexpensive, calcium-containing dietary phosphorus binders are used commonly worldwide. However, they are not suitable for every patient because of the association with elevated serum calcium, increase in vascular and valvular calcification scores, and cardiovascular and all-cause mortality. The calcium content itself in these binders has recently been implicated to upregulate FGF-23. For that reason, the noncalcium, aluminum-free agents such as sevelamer and lanthanum are being advocated. However, these drugs do not have a clearly defined effect on circulating levels of FGF-23. Although it is conceivable that targeting FGF-23 may lead to improved clinical outcomes, this remains speculative. Therefore, more studies are needed to answer the question if this can be achieved with any of the phosphorus binders, or by another (additional) pharmacological intervention.

Phytic acid inhibits lipid peroxidation in vitro

Phytic acid (PA) has been recognized as a potent antioxidant and inhibitor of iron-catalyzed hydroxyl radical formation under in vitro and in vivo conditions. Therefore, the aim of the present study was to investigate, with the use of HPLC/MS/MS, whether PA is capable of inhibiting linoleic acid autoxidation and Fe(II)/ascorbate-induced peroxidation, as well as Fe(II)/ascorbate-induced lipid peroxidation in human colonic epithelial cells. PA at 100 μM and 500 μM effectively inhibited the decay of linoleic acid, both in the absence and presence of Fe(II)/ascorbate. The observed inhibitory effect of PA on Fe(II)/ascorbate-induced lipid peroxidation was lower (10-20%) compared to that of autoxidation. PA did not change linoleic acid hydroperoxides concentration levels after 24 hours of Fe(II)/ascorbate-induced peroxidation. In the absence of Fe(II)/ascorbate, PA at 100 μM and 500 μM significantly suppressed decomposition of linoleic acid hydroperoxides. Moreover, PA at the tested nontoxic concentrations (100 μM and 500 μM) significantly decreased 4-hydroxyalkenal levels in Caco-2 cells which structurally and functionally resemble the small intestinal epithelium. It is concluded that PA inhibits linoleic acid oxidation and reduces the formation of 4-hydroxyalkenals. Acting as an antioxidant it may help to prevent intestinal diseases induced by oxygen radicals and lipid peroxidation products.

Preventive inositol hexaphosphate extracted from rice bran inhibits colorectal cancer through involvement of Wnt/β-catenin and COX-2 pathways

Nutritional or dietary factors have drawn attention due to their potential as an effective chemopreventive agent, which is considered a more rational strategy in cancer treatment. This study was designed to evaluate the effect of IP₆ extracted from rice bran on azoxymethane- (AOM-) induced colorectal cancer (CRC) in rats. Initially, male Sprague Dawley rats were divided into 5 groups, with 6 rats in each group. The rats received two intraperitoneal (i.p.) injections of AOM in saline (15 mg/kg body weight) over a 2-week period to induce CRC. IP₆ was given in three concentrations, 0.2% (w/v), 0.5% (w/v), and 1.0% (w/v), via drinking water for 16 weeks. The deregulation of the Wnt/β-catenin signaling pathway and the expression of cyclooxygenase (COX)-2 have been implicated in colorectal tumorigenesis. β-Catenin and COX-2 expressions were analysed using the quantitative RT-PCR and Western blotting. Herein, we reported that the administration of IP₆ markedly suppressed the incidence of tumors when compared to the control. Interestingly, the administration of IP₆ had also markedly decreased β-catenin and COX-2 in colon tumors. Thus, the downregulation of β-catenin and COX-2 could play a role in inhibiting the CRC development induced by IP₆ and thereby act as a potent anticancer agent.

Variability of antinutritive compounds in flaxseed flours

The use of flaxseed flours in the diets of poultry and broilers may be limited by the presence of antinutritive compounds. The content of cyanogenic glycosides, phytic acid, condensed tannins and trypsin inhibitors was evaluated in seven varieties of<em> Linum usitatissimum</em>. Phytic acid, condensed tannins and trypsin inhibitors showed significant differences among varieties. Only the concentration of cyanogenic glycosides and phytic acid in the flour deserves attention, while the content of condensed tannins and trypsin inhibitors are to acceptable levels. Since the flax meal is an important source of omega-3 for poultry and broilers, the cyanogenic glycoside and phytic acid contents in linseed has to be reduced to increase the ration to be included in the diet.

Potential of phytase-mediated iron release from cereal-based foods: a quantitative view

The major part of iron present in plant foods such as cereals is largely unavailable for direct absorption in humans due to complexation with the negatively charged phosphate groups of phytate (myo-inositol (1,2,3,4,5,6)-hexakisphosphate). Human biology has not evolved an efficient mechanism to naturally release iron from iron phytate complexes. This narrative review will evaluate the quantitative significance of phytase-catalysed iron release from cereal foods. In vivo studies have shown how addition of microbially derived phytases to cereal-based foods has produced increased iron absorption via enzyme-catalysed dephosphorylation of phytate, indicating the potential of this strategy for preventing and treating iron deficiency anaemia. Despite the immense promise of this strategy and the prevalence of iron deficiency worldwide, the number of human studies elucidating the significance of phytase-mediated improvements in iron absorption and ultimately in iron status in particularly vulnerable groups is still low. A more detailed understanding of (1) the uptake mechanism for iron released from partially dephosphorylated phytate chelates, (2) the affinity of microbially derived phytases towards insoluble iron phytate complexes, and (3) the extent of phytate dephosphorylation required for iron release from inositol phosphates is warranted. Phytase-mediated iron release can improve iron absorption from plant foods. There is a need for development of innovative strategies to obtain better effects.

Anion composition of açaı́ extracts

Many products labeled açaı́ are presently marketed as natural supplements with various claimed health benefits. Authentic açaı́ is expensive; as a result, numerous products labeled as containing açaı́ are being sold that actually contain little or no açaı́. Authentic açaı́ samples from Brazil and Florida as well as several reputed açaı́ products were analyzed by suppressed conductometric anion chromatography. Columns with different selectivities were used to obtain a complete separation of all anions. Tandem mass spectrometry was used for confirmation of the less common ions. Quinate, lactate, acetate, formate, galacturonate, chloride, sulfate, malate, oxalate, phosphate, citrate, isocitrate, and myo-inositol hexakisphosphate (phytate) were found. Only the Florida açaı́ had detectable levels of hexanoate. No açaı́ sample had any detectable levels of tartrate, which is present in abundance in grape juice, the most common adulterant. The highly characteristic anion profile and in particular the absence of tartrate can readily be used to identify authentic açaı́ products. Açaı́ from Florida had a 6 times greater level of phytate. The present analytical approach for phytate may be superior to extant methods.

Potential role and therapeutic interests of myo-inositol in metabolic diseases

Several inositol isomers and in particular myo-inositol (MI) and D-chiro-inositol (DCI), were shown to possess insulin-mimetic properties and to be efficient in lowering post-prandial blood glucose. In addition, abnormalities in inositol metabolism are associated with insulin resistance and with long term microvascular complications of diabetes, supporting a role of inositol or its derivatives in glucose metabolism. The aim of this review is to focus on the potential benefits of a dietary supplement of myo-inositol, by far the most common inositol isomer in foodstuffs, in human disorders associated with insulin resistance (polycystic ovary syndrome, gestational diabetes mellitus or metabolic syndrome) or in prevention or treatment of some diabetic complications (neuropathy, nephropathy, cataract). The relevance of such a nutritional strategy will be discussed for each context on the basis of the clinical and/or animal studies. The dietary sources of myo-inositol and its metabolism from its dietary uptake to its renal excretion will be also covered in this review. Finally, the actual insights into inositol insulin-sensitizing effects will be addressed and in particular the possible role of inositol glycans as insulin second messengers.

Absorption Studies Show that Phytase from Aspergillus niger Significantly Increases Iron and Zinc Bioavailability from Phytate-Rich Foods

Background

Iron and zinc deficiency are major public health problems affecting many parts of the world, including Southeast Asia. Infants, young children, and women of reproductive age are particularly vulnerable due to their high requirements. Even though iron and zinc are present in significant amounts in the plant-based diets typically consumed in developing countries, their bioavailability is low due to high levels of absorption inhibitors such as phytate. Phytase has been used in animal nutrition for decades to improve the bioavailability of certain minerals in feed.

Objective

To show the effect of phytase in human nutrition based on evidence from human studies. Phytase can be used either during processing or as an active food ingredient degrading dietary phytate during stomach transit time.

Methods

Evidence from human studies testing the effect of phytase on iron and zinc bioavailability using stable isotopes was reviewed.

Results

Twelve studies tested the effect of phytase on iron and five tested its effect on zinc bioavailability. Most of these studies used a phytase derived from Aspergillus niger. They found a beneficial effect unless phytate concentrations were too low or levels of inhibitors or enhancers of iron absorption were too high. Twenty to 320 phytase units per 100 g of flour significantly improved iron absorption, even though higher levels might further increase iron bioavailability. For zinc, not enough information is available to determine optimal activities.

Conclusions

Phytase clearly has a beneficial effect on iron and zinc absorption from phytate-rich foods. It also has the potential to increase the absorption of magnesium, calcium, and phosphorus in areas such as Southeast Asia where mineral deficiencies are widespread.

Increasing whole grain intake as part of prevention and treatment of nonalcoholic Fatty liver disease

In conjunction with the rise in rates of obesity, there has been an increase in the rate of nonalcoholic fatty liver disease (NAFLD). While NAFLD at least partially originates from poor diet, there is a lack of nutritional recommendations for patients with suspected or confirmed diagnosis of NAFLD, beyond eating a healthy diet, increasing physical activity, and emphasising weight loss. The limited current literature suggests that there may be opportunities to provide more tailored dietary advice for people diagnosed with or at risk of NAFLD. Epidemiological studies consistently find associations between whole grain intake and a reduced risk of obesity and related diseases, yet no work has been done on the potential of whole grains to prevent and/or be a part of the treatment for fatty liver diseases. In this review, we examine the potential and the current evidence for whole grains having an impact on NAFLD. Due to their nutrient and phytochemical composition, switching from consuming mainly refined grains to whole grains should be considered as part of the nutritional guidelines for patients diagnosed with or at risk for fatty liver disease.

Validation of an LC-MS bioanalytical method for quantification of phytate levels in rat, dog and human plasma

Myo-inositol hexakisphosphate (phytate, IP6) is a naturally occuring compound whose determination in biological matrices is chanllenging. Several benefitial properties have been attributed to IP6 in parallel with the development of suitable analytical methodologies for its analytical determination in urine and some tissues. However, there is a lack of appropriate tools for its determination in plasma samples. In this paper, a direct, sensitive and selective bioanalytical method for the determination of IP6 based on LC-MS is presented. It is the first method published to quantify IP6 in plasma matrices directly through its molecular weight, being consequently a highly specific methodology. The method has been validated in rat, dog and human plasma, according to the acceptance criteria laid down in the FDA guidance Bioanalytical Method Validation. Accuracy and precision were not greater than 15% at medium and high concentrations and not greater than 20% at the LLOQ concentration. The mean absolute recovery obtained ranged from 78.74 to 102.44%, 62.10 to 87.21% and 61.61 to 86.99% for rat, dog and human plasma respectively. The LLOQ was 500ngmL(-1) due to the presence of endogenous IP6 in blank plasma samples and the limit of detection was within the range 30-80ngmL(-1).

Composition of two Spanish common dry beans (Phaseolus vulgaris), 'Almonga' and 'Curruquilla', and their postprandial effect in type 2 diabetics

BACKGROUND

Legume consumption has been associated with a lower risk of developing type 2 diabetes. However, the type of legume is a modifier of its effect. Two Spanish dry bean varieties-white ('Almonga') and cream ('Curruquilla')-were analyzed and used in a postprandial study in type 2 diabetics to assess glucose, insulin and triacylglycerol in blood.

RESULTS

'Curruquilla' variety had higher total galactoside (stachyose, mainly), trypsin inhibitors and lectin content than 'Almonga'. The canning liquid was discarded prior to the analysis and the bean consumption by the subjects. The canning process reduced the total α-galactoside content (>50%), practically eliminated trypsin inhibitors, and no lectin content was found. After bean consumption, maximum glucose was obtained at 60 min and was three times lower than that in bread. After bean intake, maximum insulin was produced 60 min with 'Almonga' and occurred later (90 min) with 'Curruquilla' and bread. After 'Almonga' intake, the area under the curve response of triglycerides was 14% lower compared to bread (P = 0.013).

CONCLUSIONS

'Almonga' and 'Curruquilla' are similar in the content of the nutritional but not in that of the antinutritional components. Both beans showed similar effects on blood glucose and insulin in type 2 diabetics and marked differences compared to those of bread in terms of magnitude and time course, but only 'Almonga' rendered a significant reduction in the triglyceridemic response.

Whole grain foods and health - a Scandinavian perspective

The food-based dietary guidelines in the Scandinavian countries that recommend an intake of minimum 75 g whole grain per 10 MJ (2,388 kcal) per day are mainly derived from prospective cohort studies where quantitative but little qualitative details are available on whole grain products. The objective of the current paper is to clarify possible differences in nutritional and health effects of the types of whole grain grown and consumed in the Scandinavian countries. A further objective is to substantiate how processing may influence the nutritional value and potential health effects of different whole grains and whole grain foods. The most commonly consumed whole grain cereals in the Scandinavian countries are wheat, rye, and oats with a considerable inter-country variation in the consumption patterns and with barley constituting only a minor role. The chemical composition of these different whole grains and thus the whole grain products consumed vary considerably with regard to the content of macro- and micronutrients and bioactive components. A considerable amount of scientific substantiation shows that processing methods of the whole grains are important for the physiological and health effects of the final whole grain products. Future research should consider the specific properties of each cereal and its processing methods to further identify the uniqueness and health potentials of whole grain products. This would enable the authorities to provide more specific food-based dietary guidelines in relation to whole grain to the benefit of both the food industry and the consumer.

Rationale and design of a study using a standardized locally procured macronutrient supplement as adjunctive therapy to HIV treatment in Kenya

Poor nutritional status at initiation of antiretroviral therapy (ART) is predictive of mortality. Decreased dietary intake is a major determinant of weight loss in HIV. Despite a biological rationale to treat undernutrition in adults receiving ART, few studies have provided data on feasibility, safety, effectiveness, and sustainability of specific macronutrient supplements with HIV treatment in adults, especially supplements such as a food basket, a supplement approach seldom evaluated in spite of its wide use. We present the rationale and design for a study of a locally procured macronutrient supplement given to HIV-infected patients initiating ART with a body mass index (BMI) ≤20.0 kg/m(2). The objective was to determine feasibility of procurement, distribution, safety and to obtain preliminary effectiveness data for a locally procured supplement. The design was a comparative study for 200 adult participants at two Kenya government-supported clinics. The primary outcome was BMI at 24 weeks. Supplement duration was 24 weeks, total follow-up was 48 weeks, and the study included a comparison site. Novel aspects of this study include use of a standardized macronutrient supplement to protect the participant against household food sharing, and a complementary micronutrient supplement. Comprehensive data collected included dietary intake, HIV-related quality-of-life, food security, neuropsychiatric assessments, laboratory studies, and household geomapping. Assessments were made at baseline, at 24 weeks, and at 48 weeks post-ART initiation. Challenges included establishing a partnership with local millers, distribution from the HIV clinic, food safety, and tracking of participants. These findings will help inform nutrition support programming in Kenya and similar settings, and provide needed data regarding use of macronutrient supplements as an adjunctive intervention with ART.

Impact of Kidney Function on Effects of the Dietary Approaches to Stop Hypertension (Dash) Diet

Objectives

Although the Dietary Approaches to Stop Hypertension (DASH) diet lowers blood pressure in adults with hypertension, how kidney function impacts this effect is not known. We evaluated whether Estimated Glomerular Filtration Rate (eGFR) modifies the effect of the DASH diet on blood pressure, markers of mineral metabolism, and markers of kidney function.

Methods

Secondary analysis of the DASH-Sodium trial, a multicenter, randomized, controlled human feeding study that evaluated the blood pressure lowering effect of the DASH diet at three levels of sodium intake. Data from 92 participants with pre-hypertension or stage 1 hypertension during the 3450 mg /day sodium diet assignment contributed to this analysis. Stored frozen plasma and urine specimens were used to measure kidney related laboratory outcomes.

Results

Effects of the DASH diet on blood pressure, phosphorus, intact parathyroid hormone, creatinine, and albuminuria were not modified by baseline eGFR (mean 84.5 ± 18.0 ml/min/1.73 m², range 44.1 to 138.6 ml/min/1.73 m²) or the presence of chronic kidney disease (N=13%).

Conclusions

The impact of the DASH diet on blood pressure, markers of mineral metabolism, and markers of kidney function does not appear to be modified by eGFR in this small subset of DASH-Sodium trial participants with relatively preserved kidney function. Whether greater reduction in eGFR modifies the effects of DASH on kidney related measures is yet to be determined. A larger study in individuals with more advanced kidney disease is needed to establish the efficacy and safety of the DASH diet in this patient population.

Contributions to total phosphorus intake: all sources considered

High serum phosphorus is linked to poor health outcome and mortality in chronic kidney disease (CKD) patients before or after the initiation of dialysis. Dietary intake of phosphorus, a major determinant of serum phosphorus, seems to be systematically underestimated using the available software tools and generalized nutrient content databases. Several sources of dietary phosphorus including the addition of phosphorus ingredients in food processing, and phosphorus content of vitamin and mineral supplements and commonly used over-the-counter or prescription medications are not fully accounted for by the nutrient content databases and software programs in current clinical use or used in large population studies. In this review, we explore the many unknown sources of phosphorus in the food supply to identify all possible contributors to total phosphorus intake of Americans that have escaped inclusion in past intake estimates. Our goal is to help delineate areas for future interventions that will enable tighter control of dietary phosphorus intake, a critical factor to maintaining health and quality of life in CKD and dialysis patients.

Phytic acid-to-iron molar ratio rather than polyphenol concentration determines iron bioavailability in whole-cowpea meal among young women

Limited data exist on iron absorption from NaFeEDTA and FeSO(4) in legume-based flours. The current study compared iron absorption from NaFeEDTA and FeSO(4) as fortificants within and between red and white varieties of cowpea with different concentrations of polyphenols (PP) but similar phytic acid (PA)-to-iron molar ratios. We performed a paired crossover study in young women (n = 16). Red-cowpea (high-PP) and white-cowpea (low-PP) test meals (Tubani) were each fortified with ((57)Fe)-labeled NaFeEDTA or ((58)Fe)-labeled FeSO(4) and were randomly administered. Iron absorption was measured as erythrocyte incorporation of stable iron isotopes. Per serving, the mean (±SD) PP concentrations of the white- and red-cowpea-based meals were 74 ± 3.6 and 158 ± 1.8 mg, respectively, and the molar ratio of PA to iron was 3.0 and 3.3. Iron bioavailabilities from red and white cowpeas were 1.4 and 1.7%, respectively, in NaFeEDTA-fortified meals and 0.89 and 1.2%, respectively, in FeSO(4)-fortified meals. Compared with FeSO(4), fortification with NaFeEDTA increased the amount of iron absorbed from either of the cowpea meals by 0.05 to 0.08 mg (P < 0.05). Irrespective of the fortificant used, there was no significant difference in the amount of iron absorbed from the 2 varieties of cowpea. The results suggest that NaFeEDTA is more bioavailable in legume-based flours compared with FeSO(4). In cowpea-based flours, the major determinant of low iron absorption may be the high molar ratio of PA to iron and not variations in PP concentration.

Application of in vitro bioaccessibility and bioavailability methods for calcium, carotenoids, folate, iron, magnesium, polyphenols, zinc, and vitamins B(6), B(12), D, and E

A review of in vitro bioaccessibility and bioavailability methods for polyphenols and selected nutrients is presented. The review focuses on in vitro solubility, dialyzability, the dynamic gastrointestinal model (TIM)™, and Caco-2 cell models, the latter primarily for uptake and transport, and a discussion of how these methods have been applied to generate data for a range of nutrients, carotenoids, and polyphenols. Recommendations are given regarding which methods are most justified for answering bioaccessibility or bioavailability related questions for specific nutrients. The need for more validation studies in which in vivo results are compared to in vitro results is also discussed.

Protective effect of myo-inositol hexaphosphate (phytate) on bone mass loss in postmenopausal women

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.