1,721,062 research outputs found
Nutritional scores of milk and plant-based alternatives and their difference in contribution to human nutrition
Get PDFMilk consumption is in decline in developed countries due to changes in lifestyle and habits. Such a reduction is partly due to the expanding plant-based industry which provides attractive alternatives. In this study, the nutritional composition of soya, oat, almond, coconut, and rice-based beverages was compared to that of cow and goat milk by means of 4 commercial nutritional scores (NS). Contribution to the recommended daily intake (RDI) of macro- and micro-nutrients was calculated for comparison. Apart from soya, plant-based beverages (PBB) did not approximate the nutrient profile of cow and goat milk, e.g., they did not provide iodine and contained only limited amounts of calcium, potassium, and magnesium. For several traits important for human health, oat, almond, coconut, and rice-based beverages scarcely contributed to the RDI. Depending on the criteria considered for the score calculation, however, certain PBB achieved better NS than milk. Findings show the difficulty in ensuring coverage of RDI through a non-guided inclusion of PBB as a substitute for milk. Moreover, the inferior contribution of PBB to RDI compared to milk and the high variability in the nutritional scores between the different PBB brands prompts for a standardisation across the plant-based food industry to increase transparency
Bioaccessibility and tissue distribution of carotenoids and vitamin D from fortified foods
No full textNovel approaches to food fortification are being developed in order to meet dietary gaps in micronutrient intake. The efficacy of food fortification relies on bioavailability of the nutrient, i.e. the nutrient must be released from the food matrix during digestion, absorbed at the intestinal epithelial surface, and delivered to target tissues for biological activity and/or storage. Underlying the investigation of bioavailability is the need for analytical methods to determine carotenoid and vitamin D concentrations in foods and tissues. The bioaccessibility and tissue distribution of carotenoids and vitamin D were investigated from three distinct food systems. Provitamin A carotenoid levels of sorghum are being enhanced through transgenic approaches in the Africa Biofortified Sorghum project, yet bioavailability of carotenoids has not been considered. Bioaccessibility of provitamin A carotenoids were assessed from 18 biofortified and wild-type sorghum varieties by in vitro digestion. The most promising biofortified variety was identified, and contained 4-8x more bioaccessible β-carotene equivalents than wild-type sorghum. Human breast milk is a primary source of bioactive carotenoids including lutein and zeaxanthin, which may protect the developing infant retina from light-induced damage. To develop additional insights into carotenoid profiles across lactation stage and country, human milk was analyzed from twenty donors in China, Mexico, and the USA at 2, 4, 13, and 26 weeks postpartum. Bioaccessibility and intestinal absorption of breast milk from 1-6 months postpartum and 9 prototypes of lutein-fortified infant formula were assessed by a coupled in vitro digestion/ Caco-2 human intestinal cell model. Bioaccessibility of lutein was not different between human milk (29±2%) and infant formula (36±4%), or between types of lutein-fortified formula. However, accumulation efficiency of lutein by Caco-2 from human milk was over 4x greater from human milk than infant formula and increasingly efficient at low levels of lutein. Sample preparation and LC-MS/MS methodology was developed in order to assess the tissue distribution of vitamin D and 25-hydroxyvitamin D from select soft tissues. 25-hydroxyvitamin D concentrations were ~1 ng/g from both vitamin D forms in muscle, liver, and adipose tissue. Total vitamin D concentration in adipose tissue reflected serum 25-hydroxyvitamin concentration, suggesting that potential differences in tissue accumulation did not cause the disparity in bioavailability. To isolate digestive processes from further metabolism, vitamin D bioaccessibility from fortified breads and bovine milks was assessed by in vitro digestion. Vitamin D bioaccessibility was lower from bread fortified with vitamin D2 enriched yeast than from crystalline vitamin D2 fortified breads and from bovine milks. Microscopy and solvent extraction of breads further suggests that vitamin D was not released from intact yeast cells. Together, these studies strongly indicate that increasing the carotenoid or vitamin D content of foods is not sufficient for effective fortification. Carotenoid and vitamin D bioaccessibility and absorption are a function of the food matrix these nutrients are placed into. Bioavailability is not only influenced by macronutrients such as lipid to aid in micellarization, but also the microenvironment that may physically trap or chemically associate with the nutrient, as well as biological factors that may potentiate intestinal absorption. While similar observations have been made before for other food systems, these data highlight the necessity of bioavailability assessment from any novel approach to fat-soluble micronutrient fortification. (Abstract shortened by UMI.
A blueberry-enriched diet may aid in the amelioration of bone loss in the ovariectomized rat model
No full textOsteoporosis is the most common bone disease in older adults and is characterized by low bone mass and increased fragility. Women are at a higher risk for osteoporosis because of the rapid loss of bone during menopause. The decline of estrogen is accompanied by an increased bone resorption and a decreased bone formation which results in negative bone balance. Due to adverse effects on the uterus, breast and cardiovascular system, hormone replacement therapy has been discouraged. Nutritional strategies for osteoporosis prevention are being sought. It has been suggested that (poly)phenol-rich fruits may have bone protective effects. Blueberries are one of the richest sources of (poly)phenols, thus the aim of this dissertation was to determine whether a blueberry-enriched diet could aid in bone loss prevention in the ovariectomized rat model.There are hundreds of blueberry varieties which differ in (poly)phenol profiles and content. Five blueberry varieties (Ira, Montgomery, SHF2B1-21:3, Onslow and Wild Blueberry) were chosen to assess the bioavailability of its individual (poly)phenols. Bioavailability of individual phenolic metabolites was determined through a pharmacokinetic study in ovariectomized rats. The results showed that Montgomery blueberry had significantly higher bioavailability of malvidin, cyanidin and myricetin metabolites, while Ira had significantly higher bioavailability of quercetin metabolites, thus suggesting that the absorption of blueberry polyphenols and their potential to reach target tissues differed between blueberry varieties.It is important to assess what is the most appropriate dose of blueberry necessary to exert beneficial effects on bone. To determine the most adequate dose of wild blueberry to prevent bone loss in ovariectomized rats, a randomized crossover study was carried out to assess the effects of four different blueberry doses on net bone calcium retention over a 10-day treatment period. The results showed that the only dose to significantly increase net bone calcium retention by 25.6% (p = 0.0426) was the 5% blueberry diet (% w/w), while the higher doses of 10% and 15% had no effect on net bone calcium retention. This informed the last study where Montgomery blueberry and wild blueberry at a 5% dose (% w/w) were chosen to investigate the effects of an 8-week chronic feeding study on calcium metabolism, kinetics, bone microarchitecture and strength and polyphenol metabolism and distribution. A chronic consumption of the wild blueberry resulted in a trend towards minimal trabecular bone loss protection in comparison to the control diet (p=0.08). Kinetic modeling of calcium showed that the Montgomery blueberry had anabolic effects on bone through significantly increasing calcium absorption and bone deposition. The phenolic metabolism differed among blueberry varieties due to each berry’s polyphenol content and profiles and a chronic consumption of blueberry resulted in significant changes in absorption and metabolism of polyphenols. The bone marrow was investigated to determine whether there was any accumulation of phenolic acids in the tissue. Hippuric acid accumulation was significantly higher with the Montgomery blueberry treatments in comparison to control diet. Interestingly, hippuric acid content in the bone marrow was significantly and positively correlated with bone deposition calculated from kinetic modeling. Although no differences were observed on bone mineral density, strength, and microarchitecture, previous studies with a duration of 12-14 weeks have shown significant protection of a blueberry-enriched diet on bone mineral density. Because our study showed a trend for increased trabecular bone (p = 0.08) with the blueberry treatments, we conclude that an 8-week treatment was insufficient time to detect significant differences between the control and blueberry treatments. Since previous researchers before us have reported significant attenuation to bone loss immediately after OVX, it is possible that blueberry that in our study, blueberry was unable to rescue bone once lost after ovariectomy.A blueberry-enriched diet resulted in a minimal protection to bone after stabilized to OVX, but showed significant increases in calcium absorption and bone turnover in ovariectomized rats. Colonic metabolite profiles from the chronic consumption of blueberry significantly changed over time, thus providing an insight into the effects of blueberry consumption on polyphenol metabolism.</div
The role of botanicals in preventing bone loss in the postmenopausal state
No full textPostmenopausal estrogen depletion is a major contributing factor to osteoporosis in women. Current osteoporosis treatments, including hormone replacement therapy and bisphosphonates, have been challenged for their risks; therefore, there has been interest in soy isoflavones and other polyphenolic-containing substances for their potential to reduce bone loss. Many polyphenols behave as estrogens in the body, restoring some of the beneficial actions of estrogen to bone. The ability of soy isoflavones to reduce bone loss associated with estrogen deficiency is hypothesized to be dependent on isoflavone composition, dose, and equol-producing ability. The aim of this research was to determine whether equol-producing ability of an individual affects bone resorption when given soy interventions of genistein-rich or mixed isoflavone supplements of varying doses. This study was a blinded, partially-randomized, crossover intervention trial in which postmenopausal women (n=24) were prescreened for their ability to convert daidzein to equol (n=8 equol-producers). The subjects received 5 soy isoflavone extract interventions, including two doses of a genistein-rich soy supplement and three doses of mixed isoflavones in various proportions, as well as a bisphosphonate (risedronate) positive control. Subjects were intravenously dosed with 41Ca to deep label their skeletons so that urinary excretion of 41Ca could be measured to assess bone resorption, calculated as relative resorption (RR). There was no difference between equol-producers and non-producers, and the commercially available Novasoy® had the greatest antiresorptive effect of the soy interventions with RR=0.924 (p\u3c0.0001) compared to risedronate (RR=0.847, p=0.0009). The radio-isotope, 45Ca, was used as a proxy to the 41Ca methodology in human subjects to investigate the effect of supplementation of high and low doses of blueberry, plum, grape, grape seed extract, and resveratrol, as well as two forms of soy isoflavones as a crossover design in ovariectomized rats (n=16 rats for each extract intervention). Bone resorption was assessed by urinary excretion of 45Ca/Ca ratio during an intervention period compared to a washout period. A high dose of grape seed extract, and both doses of blueberry and plum were able to reduce bone resorption with relative resorption ranging from 0.66 to 0.84. There was a non-significant dose-response in grape seed extract and a significant dose-response in plum (p=0.02)
Bioavailability of calcium salts and the effects of soy isoflavones on calcium and bone metabolism in adult ovariectomized rats
No full textOsteoporosis is a disease resulting from bone loss and from the structural deterioration of bone tissue. Yet osteoporosis is both controllable and preventable. In terms of prevention, a good source of calcium supplementation is important in promoting strong, healthy bones. The bioavailability of calcium ascorbate and calcium acetate was studied in an animal model using a radioactive tracer technique. At two dosage levels, calcium from calcium ascorbate was absorbed higher than from calcium acetate, indicating calcium ascorbate is a better bioavailable calcium supplement. Alpha-lactalbumin, a whey protein fraction, further enhanced calcium absorption from both salts in an animal model. Therefore, calcium ascorbate in combination with alpha-lactalbumin was a superior bioavailable calcium source. Several animal and short-term human studies indicate that isoflavones may be used as an alternative therapy to estrogen replacement therapy. However, the results were contradictory. The inadequacy of information and controversy on skeletal effects of isoflavones led us to design the present study to test the effectiveness of soy isoflavones on treating osteoporosis in comparison to the estrogen replacement therapy in an adult animal model for postmenopausal osteoporosis. Unmated 6 mo. old ovariectomized and sham operated female Sprague-Dawley rats were randomly assigned to 9 groups (16 rats/group). Calcium metabolic balance, bone densitometry, bone histomorphometry and bone mechanical testing were used to investigate calcium and bone metabolism. After ovariectomy, estrogen prevented bone loss in trabecular bone and suppressed formation on both trabecular and cortical bone surfaces. Isoflavones given as soy protein or supplements did not prevent trabecular bone loss. Combining isoflavones with estrogen had no additional benefits. None of the treatments affected calcium absorption or calcium balance significantly. Therefore, we conclude that soy isoflavones did not alter calcium metabolism or bone metabolism at the doses tested
Calcium metabolism in African American adolescent females
No full textOsteoporosis, a condition of reduced bone mass resulting in increased skeletal fragility, affects 25–30 million Americans. African Americans have greater bone density and less incidence of osteoporosis than Caucasians or Asians. Approximately twenty-five percent of women of Anglo-Saxon origin over the age of fifty have osteoporosis. The prevalence of osteoporosis of the total hip is 16% among Hispanic women and only 10% among African American women (Looker et al., 1995). Within the female adult population there are more than 1.5 million bone fractures annually, resulting in healthcare costs in excess of $13 billion every year (Concensus Development Conference, 1993). It is important to understand racial differences in calcium handling throughout life. Twenty-one girls were recruited to participate in a three-week metabolic study which was conducted to measure calcium balance and calcium kinetics in 11–14 year old adolescent girls. A four day menu cycle consisted of typical teenage foods and averaged 1209 ± 2.5 mg/day of calcium. The girls ate and lived in a fraternity house on Purdue\u27s campus to simulate a free-living environment. The adolescents showed a positive balance of 460 ± 236 mg/day, and excreted 37 ± 30 mg urinary calcium/day, and 661 ± 211 mg fecal calcium/day. Stable isotopic tracer techniques and compartmental modeling were used to determine calcium kinetics. Bone deposition was 1983 ± 603 mg/day, bone resorption was 1483 ± 533 mg/day, resulting in a net gain of 501 ± 222 mg/day calcium deposited in bone. Compared with Caucasian adolescent females, African Americans had significantly greater bone mineral density, balance, bone balance, bone deposition, bone resorption, and significantly less urinary and fecal excretion of calcium/day. Turnover of a compartment considered to be exchangeable calcium on bone was almost twice as fast in the African American, compared to the Caucasian girls, in marked contrast to biochemical bone turnover markers, which were lower. Biochemical markers of bone turnover underestimated bone turnover as determined by calcium kinetics in African American adolescent girls
Effects of calcium salt and IGF -I infusion on calcium kinetics and bone parameters in growing rats
No full textCalcium is the major cation of bone mineral, the process of skeletal development and remodeling is inherently related to calcium metabolism. Kinetic modeling enables the rapid assessment of changes that occur associated with age, therapeutic intervention. Therefore, calcium metabolism was investigated using kinetic analysis in rats via several independent studies. First, calcium absorption from two different calcium salts, calcium ascorbate and calcium acetate, was compared. As measured by femur uptake, fractional calcium absorption from calcium ascorbate was substantially higher than that from calcium acetate (70% ± 5 vs. 45% ± 5) on a 25 mg test load. To further confirm this observation, a metabolic study was conducted. Four groups of male Sprague-Dawley rats (n = 10/group) received oral or intravenous doses of 25 mg Ca as calcium ascorbate or calcium acetate. Each dose contained 25 μCi 45Ci. Sequential blood, urine and fecal samples were collected over 48 hours. Data was analyzed by compartmental modeling. Results of kinetic analysis demonstrated that the higher absorption of calcium ascorbate was due to a longer residence time in the gut. Secondly, the effect of Insulin-like growth factor I (IGF-I) on calcium metabolism in growing rats was examined using the same kinetic model. IGF-I is an important mediator during pubertal skeletal growth, and has been considered as a potential treatment for osteoporosis. Measurement of bone quality and calcium metabolism were first determined in rats from age 6 weeks to 31 weeks in order to determine the timing for IGF-I intervention. Human recombinant IGF-I/IGFBP-3 complex was chronically infused into female rats at two different ages: 6 and 9 weeks of age, representing early puberty and young adulthood in humans. After 4 weeks of treatment, body weights of IGF-I treated rats were higher than control rats. Femoral calcium content was also significantly higher in IGF-I treated pubertal rats, 493 ± 42, compared to control rats, 368 ± 24 mg calcium/g ash weight. Kinetic analysis revealed the treatment resulted in higher intestinal calcium absorption and faster calcium clearance from the circulation in pubertal rats. However, the IGF-I treatment failed to alter calcium metabolism in young adult rats
A longitudinal study of the effect of genistein on bone mass and bone architecture in an innovative perimenopausal mouse model
No full textIn this experiment the effect of genistein (GEN), a soy-derived isoflavone, was assessed in a novel murine model treated with the ovotoxic chemical vinyl-chlorohexene diepoxide (VCD) to gradually induce a menopausal state in which bone changes were monitored. This ovary-intact model more accurately represents the hormonal transition to menopause experienced by human females, as opposed to an ovariectomized (OVX) animal model which only simulates surgical menopause, a medical procedure responsible for \u3c13% of menopause in women. VCD-treated mice and OVX mice were fed a casein-based diet, either with or without the addition of genistein (0.4g GEN/kg diet), and plasma concentrations reached levels documented in humans habitually consuming a soy diet. Significant positive treatment effects were observed in OVX mice fed GEN versus OVX controls in the proximal tibia (i.e., total and subcortical bone mineral density and bone area increased) based on longitudinal in vivo peripheral computed tomography. High resolution micro-computed tomography of excised bones revealed that trabeculae of the fifth vertebral body and cortical bone in the midshaft of the femur were significantly thicker in OVX mice fed GEN versus OVX mice on a phytoestrogen-free diet. The difference in cortical thickness attributed to GEN in ovariectomized mice translated to an increase in the peak load withstood by the femur during three-point mechanical testing. In the transition to menopause, VCD-treated mice in this experiment did not lose an amount of bone that was statistically significantly different from the sham controls, making the assessment of GEN effects under these circumstances impossible. VCD-treated mice exhibited a trend towards higher concentrations of circulating androgens which may have substantially contributed to the attenuation of bone loss, rendering the role of GEN non apparent. The magnitude of bone loss due to VCD-treatment in skeletally mature mice was not known prior to this experiment, however, with the data generated from this study it should be possible to plan a more focused investigation of this animal model in the future. Prospective power calculations suggest streamlining the experiment so there are less groups, and focusing in on the vertebral trabeculae region in VCD-treated mice, would be most advantageous
Soy protein versus milk protein and urinary calcium excretion in postmenopausal women
No full textHigh animal protein intake and low vegetable protein intake increase dietary acid load as indicated by high urinary excretions of sulfate, ammonium, net acid, and calcium. The primary purpose of the present study was to compare dietary soy protein with milk protein as a calcium-conserving agent in postmenopausal women. Fifteen women were fed a controlled diet containing 40g protein powder as casein-whey (milk) or soy in a crossover design. Mean urinary calcium excretion on the soy protein-based diet (80mg ± 42) was 35% lower (p \u3c 0.01) than on the milk protein diet (123mg ± 64). The 18% difference in SAA content of the powders was reflected in greater (p \u3c 0.05) urinary sulfate excretion on the milk protein (4.5mEq ± 1.1) vs. the soy protein-based diet (3.3mEq ± 0.97). Moreover, there was no significant difference in NAE or urinary creatinine. The greater urinary calcium excretion on the milk vs. soy protein-based diet was not accompanied by a greater creatinine clearance. Furthermore, there was no significant difference between the soy and milk protein-based diet in urinary nitrogen excretion or nitrogen balance. There were no differences found in any of the calcitropic hormones (PTH, 1,25 OH2-D, and 25 OH-D) or any of the biochemical markers of bone turnover (NTX, BAP, OC, DPD). However, there was a 37% higher fractional renal tubular reabsorption of calcium and a 27% lower calcium clearance on the soy (0.041 ± .025 and 1.95ml/min, respectively) vs. milk protein-based diet (0.029 ± 0.016 and 2.66ml/min ± 1.8, respectively). In conclusion, soy protein is calcium-conserving as indicated by lower urinary calcium excretion
Moderate exercise-induced changes in the iron status of young adult women
No full textThe effect of moderate aerobic exercise on the iron status of previously sedentary college-age women was determined by conducting a short-term (12 Wks) and a long-term (24 Wks) study. In the first study, subjects (N = 60) were randomly assigned to one of the following groups: (1) 50 mg/d iron supplement, low iron diet; (2) 10 mg/d iron supplement, low iron diet; (3) Placebo, free choice diet; (4) Meat supplement to achieve recommended allowance for iron; and (5) Control, free choice diet. The long-term study (N = 62) was designed similarly and had all the above groups except the group that received the 10 mg/d iron supplement. In both the studies, all groups except the control were required to exercise a minimum of 3d/wk at 70-90% of their maximal heart rate. VO\sb{2max} was measured at baseline and at the end of the study. Blood was sampled at baseline and every 4 weeks thereafter. Iron status indices were measured in both the studies. Mechanisms inducing changes in the iron status were also elucidated in the long-term study. In the short-term study, a decline in hemoglobin at the end of 4 weeks was observed in all the exercising groups. Transferrin saturation and serum ferritin were also negatively impaired in exercising subjects in study 1. The results from the long-term study in terms of changes in iron status were not as striking as the short-term study probably because of a higher baseline iron status in these subjects. However, a repeated time measures analysis of covariance with baseline hemoglobin as covariate indicated a significantly (p 0.05) lower post hemoglobin in the Placebo group of study 2, compared to the iron supplemented groups. A significant drop in serum ferritin was detected in the Placebo group after 24 weeks of exercise. The results from both these studies together indicate that moderate aerobic exercise can compromise iron status in previously untrained women. An initial declining trend in haptoglobins in the exercising groups and a significant increase in serum erythropoietin in the Placebo group after 24 weeks suggest that a mild hemolysis might be occurring with exercise. However, a significant increase in haptoglobins at week 24 in the Meat group and an overall improvement in the iron status indices in the meat and iron supplemented groups in both the studies indicate that the initial alterations in the iron status induced by moderate aerobic exercise can be offset by oral iron therapy or by meeting the daily iron requirements through muscle food consumption
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