Concept: Dietary mineral
BACKGROUND: Vitamin K2 contributes to bone and cardiovascular health. Therefore, two vitamin K2 homologues, menaquinone-4 (MK-4) and menaquinone-7 (MK-7), have been used as nutrients by the food industry and as nutritional supplements to support bone and cardiovascular health. However, little is known about the bioavailability of nutritional MK-4. To investigate MK-4 and MK-7 bioavailability, nutritional doses were administered to healthy Japanese women. FINDINGS: Single dose administration of MK-4 (420 mug; 945 nmol) or MK-7 (420 mug; 647 nmol) was given in the morning together with standardized breakfast. MK-7 was well absorbed and reached maximal serum level at 6 h after intake and was detected up to 48 h after intake. MK-4 was not detectable in the serum of all subjects at any time point. Consecutive administration of MK-4 (60 mug; 135 nmol) or MK-7 (60 mug; 92 nmol) for 7 days demonstrated that MK-4 supplementation did not increase serum MK-4 levels. However, consecutive administration of MK-7 increased serum MK-7 levels significantly in all subjects. CONCLUSIONS: We conclude that MK-4 present in food does not contribute to the vitamin K status as measured by serum vitamin K levels. MK-7, however significantly increases serum MK-7 levels and therefore may be of particular importance for extrahepatic tissues.
Selenium (Se) is an essential human micronutrient with critical roles in immune functioning and antioxidant defence. Estimates of dietary Se intakes and status are scarce for Africa although crop surveys indicate deficiency is probably widespread in Malawi. Here we show that Se deficiency is likely endemic in Malawi based on the Se status of adults consuming food from contrasting soil types. These data are consistent with food balance sheets and composition tables revealing that >80% of the Malawi population is at risk of dietary Se inadequacy. Risk of dietary Se inadequacy is >60% in seven other countries in Southern Africa, and 22% across Africa as a whole. Given that most Malawi soils cannot supply sufficient Se to crops for adequate human nutrition, the cost and benefits of interventions to alleviate Se deficiency should be determined; for example, Se-enriched nitrogen fertilisers could be adopted as in Finland.
Vitamin D insufficiency in children may have long-term skeletal consequences as vitamin D affects calcium absorption, bone mineralization and bone mass attainment.
Dietary supplements, such as herbal or complementary nutritional products and micronutrients (vitamins and minerals), are commonly used in the United States, yet national data on adverse effects are limited.
Iron, potassium, zinc, and other minerals might impact the development of premenstrual syndrome (PMS) through multiple mechanisms, but few studies have evaluated these relations. We conducted a case-control study nested within the prospective Nurses' Health Study II (1991-2001). Participants were free from PMS at baseline. After 10 years, 1,057 women were confirmed as PMS cases and 1,968 as controls. Mineral intake was assessed using food frequency questionnaires completed in 1991, 1995, and 1999. After adjustment for calcium intake and other factors, women in the highest quintile of nonheme iron intake had a relative risk of PMS of 0.64 (95% confidence interval (CI): 0.44, 0.92; P for trend = 0.04) compared with women in the lowest quintile. Women in the highest quintile of potassium intake had a relative risk of 1.46 (95% CI: 0.99, 2.15; P for trend = 0.04) compared with women in the lowest quintile. High intake of zinc from supplements was marginally associated with PMS (for intake of ≥25 mg/day vs. none, relative risk = 0.69, 95% CI: 0.46, 1.02; P for trend = 0.05). Intakes of sodium, magnesium, and manganese were unrelated to PMS risk. These findings suggest that dietary minerals may be useful in preventing PMS. Additional studies are needed to confirm these relations.
Ensuring that a woman is well-nourished, both before and during pregnancy, is crucial for the health of the woman and that of the unborn child.(1) Maternal deficiency in key nutrients has been linked to pre-eclampsia, restricted fetal growth, neural tube defects, skeletal deformity and low birth weight.(1,2) Many nutritional supplements containing vitamins, minerals and other micronutrients are heavily marketed to women for all stages of pregnancy. However, much of the evidence for vitamin supplementation in pregnancy comes from studies carried out in low-income countries,(3) where women are more likely to be undernourished or malnourished than within the UK population. The challenges lie in knowing which supplements are beneficial and in improving uptake among those at most need. Here we summarise current UK guidance for vitamin supplementation in pregnancy and review the evidence behind it.
Proper nutrition, not simply adequate energetic intake, is needed to achieve optimal dance performance. However, little scientific research exists concerning nutrition in dance, and so, to propose nutritional guidelines for this field, recommendations need to be based mainly on studies done in other physically active groups. To diminish the risk of energy imbalance and associated disorders, dancers must consume at least 30 kcal/kg fat-free mass/day, plus the training energy expenditure. For macronutrients, a daily intake of 3 to 5 g carbohydrates/kg, 1.2 to 1.7 g protein/kg, and 20 to 35% of energy intake from fat can be recommended. Dancers may be at increased risk of poor micronutrient status due to their restricted energy intake; micronutrients that deserve concern are iron, calcium, and vitamin D. During training, dancers should give special attention to fluid and carbohydrate intake in order to maintain optimal cognition, motivation, and motor skill performance. For competition/stage performance preparation, it is also important to ensure that an adequate dietary intake is being achieved. Nutritional supplements that may help in achieving specific nutritional goals when dietary intake is inadequate include multivitamins and mineral, iron, calcium, and vitamin D supplements, sports drinks, sports bars, and liquid meal supplements. Caffeine can also be used as an ergogenic aid. It is important that dancers seek dietary advice from qualified specialists, since the pressure to maintain a low body weight and low body fat levels is high, especially in styles as ballet, and this can lead to an unbalanced diet and health problems if not correctly supervised.
In metabolic bone diseases, the alterations in fibrillar level bone-material quality affecting macroscopic mechanical competence are not well-understood quantitatively. Here, we quantify the fibrillar level deformation in cantilever bending in a mouse model for hereditary rickets (Hpr). Microfocus in-situ synchrotron small-angle X-ray scattering (SAXS) combined with cantilever bending was used to resolve nanoscale fibril strain in tensile- and compressive tissue regions separately, with quantitative backscattered scanning electron microscopy used to measure microscale mineralization. Tissue-level flexural moduli for Hpr mice were significantly (p<0.01) smaller compared to wild-type (~5 to 10-fold reduction). At the fibrillar level, the fibril moduli within the tensile and compressive zones were significantly (p<0.05) lower by ~3- to 5-fold in Hpr mice compared to wild-type mice. Hpr mice have a lower mineral content (24.2±2.1Cawt.% versus 27.4±3.3Ca wt.%) and its distribution was more heterogeneous compared to wild-type animals. However, the average effective fibril modulus did not differ significantly (p>0.05) over ages (4, 7 and 10weeks) between tensile and compressive zones. Our results indicate that incompletely mineralized fibrils in Hpr mice have greater deformability and lower moduli in both compression and tension, and those compressive and tensile zones have similar moduli at the fibrillar level.
The aim of this study was to assess nutritional supplement use among fitness club participants in Tehran, Iran. A cross sectional study was conducted in 24 fitness clubs throughout the city of Tehran, Iran. A total of 1625 fitness club participants were recruited to participate in this study. They were asked to complete a self-administered pre-tested questionnaire. Descriptive statistics and chi-square test were performed to determine the characteristics of participants, reasons for supplement use, sources of information and also the influential advisors regarding nutritional supplement use. A high prevalence rate of nutritional supplement use (66.7%) was reported. Overall, multivitamin-mineral (43.8%) and iron tablets (30.5%) were the common nutritional supplements used and only a small number of participants used illegal substances (0.5%). Younger participants were more likely to use ergogenic aids, whereas, older participants were more likely to use vitamin D. Males were more likely than females to use creatine and amino acids, whereas, iron tablets and mint water were more common among females. Also, males were more likely to use nutritional supplements for increasing energy, whereas, females were more likely to use nutritional supplements for nutritional deficiencies. In conclusion, a high prevalence rate of nutritional supplement use was seen among participants.
Influence of a nickel smelter plant on the mineralogical composition of attic dust in the Tikveš Valley, Republic of Macedonia.
- Environmental science and pollution research international
- Published almost 5 years ago
Mineral phases and their content were determined in attic dust samples collected from 27 houses in the Tikveš Valley, Republic of Macedonia. By using quantitative X-ray diffraction, the principal mineral phases were determined to be the serpentinite group (chrysotile, lizardite) and amphibole group of minerals (ribecite, tremolite, actinolite) present in the attic dust samples from this region which are not common constituents of urban dust. Strong correlations existed between these mineral phases in the dust and those in ores processed at a ferronickel smelter plant situated in this region. Spatial distributions of specific mineral phases were made and were consistent with wind directions and predicted deposition (60-70 %) of dust emitted from the metallurgical plant.