Si Intake Research Articles

Silicon Supplementation for Bone Health: An Umbrella Review Attempting to Translate from Animals to Humans.

Studies have attempted to demonstrate the benefits of silicon on bone health using a wide range of Si amounts-provided in the diet or through supplementation-and several different animal species. Previous studies in humans have also demonstrated a positive correlation between Si intake and bone health measures. The aim of the current review is to determine the effective levels of Si intake or supplementation that influence bone health to better inform future study designs and guidelines. Articles were identified using one of two search terms: "silicon AND bone" or "sodium zeolite A AND bone". Articles were included if the article was a controlled research study on the effect of Si on bone health and/or mineral metabolism and was in English. Articles were excluded if the article included human subjects, was in vitro, or studied silica grafts for bone injuries. Silicon type, group name, Si intake from diet, Si supplementation amount, animal, and age at the start were extracted when available. Dietary Si intake, Si supplementation amount, and the amount of Si standardized on a kg BW basis were calculated and presented as overall mean ± standard deviations, medians, minimums, and maximums. Studies that left out animal weights, amount of food or water consumed, or nutrient profiles of the basal diet were excluded from these calculations. Standardized Si intakes ranged from 0.003 to 863 mg/kg BW, at times vastly exceeding current human Si intake recommendations (25 mg/d). The lack of data provided by the literature made definitively determining an effective threshold of supplementation for skeletal health difficult. However, it appears that Si consistently positively influences bone and mineral metabolism by around 139 mg Si/kg BW/d, which is likely unfeasible to attain in humans and large animal species. Future studies should examine this proposed threshold more directly and standardize supplemental or dietary Si intakes to kg BW for better study replication and translation.

Urinary Excretion of Silicon in Men, Non-pregnant Women, and Pregnant Women: a Cross-sectional Study

Silicon is a trace element found mainly in plant-based food and proposed to be beneficial for bone health. Urinary excretion of Si has been shown to be a surrogate measure of its uptake in the gastrointestinal tract. The objective of this study was to describe and compare the levels of urinary Si excretion, and consequently Si uptake, in Swedish men, non-pregnant women, and pregnant women. No formal assessment of dietary Si intake was carried out in this study. This cross-sectional study included 89 men, 42 non-pregnant women, and 60 pregnant women. The subjects collected urine over a 24-h period and the samples were assayed for total Si using inductively coupled plasma optical emission spectrometry. The excretion levels of creatinine were used to validate the completeness of the urine sample collections. The mean 24-h urinary excretions of Si were 7.8 mg for the cohort of young men, 7.6 mg for the cohort of non-pregnant women, and 12.4 mg for the cohort of pregnant women. Creatinine excretion was similar between pregnant and non-pregnant women (10.4 vs. 10.8 mmol/day) and significantly higher in men (15.4 mmol/day). The pregnant women excreted significantly higher levels of Si than the young men and non-pregnant women, respectively (p < 0.05). The higher urinary excretion of Si by pregnant women compared with men and non-pregnant women is a novel finding possibly caused by temporary physiological changes during pregnancy such as increased gastrointestinal uptake of Si, altered bone metabolism, and increased renal excretion of Si.

Dietary Silicon and Its Impact on Plasma Silicon Levels in the Polish Population.

Silicon in nutritional amounts provides benefits for bone health and cognitive function. The relationship between silicon intake from a common daily diet and silicon blood level has been scarcely elucidated, so far. The aim of this study was to analyze the associations between plasma silicon levels and the total and bioavailable silicon intake—along with the contribution of silicon made by food groups—in a healthy adult Polish population. Si intake was evaluated in 185 healthy adults (94 females and 91 males, aged 20–70) using a 3-day dietary recall and a database on the silicon content in foods, which was based on both previously published data and our own research. Fasting plasma silicon levels were measured in 126 consenting subjects, using graphite furnace atomic absorption spectrometry. The silicon intake in the Polish population differed significantly according to sex, amounting to 24.0 mg/day in women and 27.7 mg/day in men. The median plasma silicon level was 152.3 µg/L having no gender dependency but with a negative correlation with age. Significant correlations were found between plasma silicon level and total and bioavailable silicon intake, as well as water intake in the diet (r = 0.18, p = 0.044; r = 0.23, p = 0.011; r = 0.28, p = 0.002, respectively). Silicon intakes from non-alcoholic beverages, cereal foods, and carotene-rich vegetables were also positively associated with plasma silicon levels. These results may help establish dietary silicon recommendations and formulate practical advice on dietary choices to ensure an appropriate supply of silicon. The outcome of this study, however, needs to be confirmed by large-scale epidemiological investigations.

Relationship Between Dietary Intake and Urinary Excretion of Silicon in Free-Living Korean Adult Men and Women.

Previous studies have reported that silicon (Si) has a positive effect on bone health, immune response, and cognitive health. However, basic and important studies on evaluating dietary intake and urinary excretion of Si are limited. The aim of this study was to evaluate dietary Si intake and urinary excretion according to gender and age in healthy and free-living Korean adults and to investigate the relationship between them with gender. In this cross-sectional study, anthropometric measurements, dietary assessment using a food record, and a 24-h urine collection were conducted in 80 healthy Korean adults (40 males and 40 females; groups of 8 subjects representing each decade of life [20s to 60s]) with self-selected diet. The dietary assessment and 24-h urine collection were performed twice at intervals of 3days. Daily intake of Si was estimated using a Si database of food composition. Urinary excretion of Si was analyzed using ICP-OES. The mean dietary Si intake was 22.8mg/day for men and 19.3mg/day for women without significant difference according to their gender and age. Si intake was the highest from vegetables both in men and women, followed by grains, beverages, and fruits in men and by grains, fruits, and milks in women. Urinary Si excretion was significantly higher in men (9.8mg/day) than women (9.3mg/day), and significantly increased with age only in women. Regarding the relationship between dietary Si intake and urinary Si excretion, a significantly positive correlation was found in men, but not in women. Longitudinal and balance studies to elucidate gender differences in Si nutrition are needed.

Dynamic Modeling of Silicon Bioavailability, Uptake, Transport, and Accumulation: Applicability in Improving the Nutritional Quality of Tomato.

Silicon is an essential nutrient for humans, additionally is beneficial for terrestrial plants. In plants Si enhances tolerance to different types of stress; in humans, it improves the metabolism and increases the strength of skeletal and connective tissues as well as of the immune system. Most of the Si intake of humans come from edible plants creating a double benefit: first, because the absorption of Si increases the antioxidants and other phytochemicals in plants, thereby increasing its functional value, and second because the higher concentration of Si in plants increases intake in human consumers. Therefore, it is desirable to raise the availability of Si in the human diet through the agronomic management of Si accumulator species, such as corn, wheat, rice, soybeans, and beans. But also in such species as tomatoes, carrots, and other vegetables, whose per capita consumption has increased. However, there are few systematized recommendations for the application and management of Si fertilizers based on the physicochemical factors that determine their availability, absorption, transport, and deposition in cells and tissues. This study presents updated information about edaphic and plant factors, which determine the absorption, transport, and deposition rates in edible organs. The information was integrated into an estimated dynamic model that approximates the processes previously mentioned in a model that represents a tomato crop in soil and soilless conditions. In the model, on the other hand, was integrated the available information about key environmental factors related to Si absorption and mobilization, such as the temperature, pH, and soil organic matter. The output data of the model were compared against information collected in the literature, finding an adequate adjustment. The use of the model for educational or technical purposes, including the possibility of extending it to other horticultural crops, can increase the understanding of the agronomic management of Si in plants.

Silicon intake and its relationship with bone mineral density in healthy Korean adults

Silicon (Si) is the most abundant element next to oxygen and has been reported to play an important role in bone and connective tissue formation. However, the relationship between dietary Si intake in self‐selected diet and bone mineral density has not been well established. The purpose of this study was to evaluate Si intake and investigate its relationship with bone mineral density in healthy adults using the data from Korea National Health and Nutrition Examination Survey (2010‐2011). A total of 8,698 adults aged 19 to 64 years (male 3,693, female 5,005) were participated in this study. Daily Si intake of the total subjects was 30.87 mg (male vs. female; 35.20 mg/d vs. 26.52 mg/d, p&lt;0.0001), and 15.12 mg per 1,000 kcal (male vs. female; 14.62 mg/1,000 kcal vs. 15.82 mg/1,000 kcal, p&lt;0.0001). The bone mineral density of lumbar spine of the total subjects increased with increment of Si density of the diet (Q1 vs. Q4; 0.907 g/cm2 vs. 0.937 g/cm2) after adjusting age (p&lt;0.0001). The similar results were found in the male and female subjects (p&lt;0.0001, respectively). These results may represent that higher Si intake from the diet is associated with bone health promotion. “This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2011‐0010880)”

A review of the effects of dietary silicon intake on bone homeostasis and regeneration.

Increasing evidences suggest that dietary Silicon (Si) intake, is positively correlated with bone homeostasis and regeneration, representing a potential and valid support for the prevention and improvement of bone diseases, like osteoporosis. This review, aims to provide the state of art of the studies performed until today, in order to investigate and clarify the beneficial properties and effects of silicates, on bone metabolism. We conducted a systematic literature search up to March 2013, using two medical databases (Pubmed and the Cochrane Library), to review the studies about Si consumption and bone metabolism. We found 45 articles, but 38 were specifically focused on Si studies. RESULTS showed a positive relationship between dietary Si intake and bone regeneration.

Silicon content in beers from Korean market and estimation of its alimentary uptake

Silicon content of Korean domestic beer was approximately 13.2 mg/l, which was 142% higher than 9.24 mg/l in imported beer. The contents of Ca and Mg were in the range of 31&amp;ndash;33 mg/l and 39-41 mg/l, respectively, which were similar in Korean domestic and imported beers. Through beer ingestion, the men&amp;rsquo;s average Si intake was approximately 24.3 mg/day, which was 195% higher than the women&amp;rsquo;s average Si intake (12.4 mg/day). In addition, it was found that 20&amp;ndash;29 aged men and women took approximately 33.7 and 25.1 mg/day of Si, respectively, which are higher Si intakes through beer ingestion as compared to other age ranges. As to people in other age-ranges, the women&amp;rsquo;s Si intake through beer ingestion was half that of men&amp;rsquo;s. Domestic beer-1 and beer-2 had 8.50 and 6.45 Si &amp;mu;g/won of Si content per unit price, respectively. Taken together with these results, it was estimated that the more expensive the price of beer, the lower the Si content per unit price. Therefore, it is supposed that the cheap Korean domestic beer is an effective supplier of Si, the beer being considered the major resource for Si intake by humans inKorea. &amp;nbsp;

Evaluation of silicon intake through consumption of Takju, Soju, and wine

The commercial and lab-brewed takju had the similar silicon (Si) contents, which were approximately 6.8 and 7.7 mg/L takju, respectively. Lab-brewed takju had approximately 7.7 mg/L of Si, which was 27.9% recovery of Si in all materials for brewing. Otherwise, lab-brewed wine showed approximately 10.4 mg/L of Si, which was 67.7% recovery. The Si contents of lab-brewed wine were approximately 10.4 mg/L wine, which was approximately 135% of average Si contents of lab-brewed takju. Commercial soju contained approximately 3.99 mg/L of Si, which was 38% of Si contents of brewed wine. It was investigated that men and women ingest approximately 1,400 and 186 μg/day (average value) of Si through soju. This study will help to estimate the Si intake amount through alcoholic beverages ingestion, based on Si contents in Korean traditional wines, such as takju, soju, and wine.

Effects of Silicon on Osteoblast Activity and Bone Mineralization of MC3T3-E1 Cells

Previous studies have reported that dietary silicon (Si) intake is positively associated with bone health including bone mineral density. Although the amount of Si intake is high among trace elements in humans, how dietary Si affects bone formation at the cellular level is not well addressed. The purpose of this study was to investigate the role of Si in osteoblast activity and bone mineralization. MC3T3-E1 was cultured as mature osteoblasts and treated with sodium metasilicate (0, 1, 5, 10, 25, 50, and 100 μM) as a source of Si. After 7 days of treatment, 5 and 10 μM of sodium metasilicate significantly increased intracellular alkaline phosphatase activity (p < 0.05) when compared to the control. Additionally, all doses of sodium metasilicate (1, 5, 10, 25, 50, and 100 μM) increased mineralized nodule formation at 14 days of differentiation as evidenced by increased Alizarin Red S staining. In the analysis of gene expression, 50 μM of sodium metasilicate upregulated type I collagen (COL-I) compared to the control group. However, the increase of COL-I gene expression as a result of treatment with 1, 10, 25, and 100 μM of sodium metasilicate did not reach statistical significance. mRNA expression of insulin-like growth factor-I and receptor activator of NF-κB ligand was not significantly changed at any dose of sodium metasilicate (0, 1, 5, 10, 25, 50, and 100 μM). In light of the results, we conclude that Si has a positive effect on bone metabolism by enhancing osteoblast mineralization activity.

Dietary silicon interacts with oestrogen to influence bone health: Evidence from the Aberdeen Prospective Osteoporosis Screening Study

BackgroundSilicon (Si), as Si(OH)4, is derived mainly from plant-based foods. Dietary Si is associated with bone mineral density (BMD) in premenopausal but not postmenopausal women. ObjectiveTo examine the association between Si intake and markers of bone health in middle-aged women and to test for interaction with oestrogen status. MethodsFemoral neck (FN) and lumbar spine (LS) BMD, urinary markers of bone resorption (free pyridinoline and deoxypyridinoline cross-links relative to creatinine, fPYD/Cr and fDPD/Cr) and serum markers of bone formation (N-terminal propeptide of type 1 collagen, P1NP) were measured in a cohort of 3198 women aged 50–62years (n=1170 current HRT users, n=1018 never used HRT). Dietary Si, bioavailable Si and dietary confounders were estimated by food frequency questionnaire. ResultsMean FN BMD was 2% lower (p<0.005) in the lowest quartile (Q1) compared to the top quartile of energy-adjusted Si intake (Q4) (mean (SD) Q1, 16 (4.0) mg/d; Q4, 31.5 (7.3) mg/d). Energy-adjusted Si intake was associated with FN BMD for oestrogen-replete women only (late premenopausal women (r=+0.21, p=0.03); women on HRT [r=+0.09, p<0.001]). There was an interaction between oestrogen status and quartile of energy-adjusted Si intake on FN BMD, which was significant after adjustment for confounders (F=3.3, p=0.020), and stronger for bioavailable Si (F=5.0. p=0.002). Quartile of energy-adjusted dietary Si intake was negatively associated with fDPD/Cr and fPYD/Cr (p<0.001) and positively with P1NP (p<0.05). ConclusionsThis study suggests that oestrogen status is important for Si metabolism in bone health. Further work is required to elucidate the mechanism.

Dietary silicon intake in post-menopausal women

Si has been suggested as an essential element, and may be important in optimal bone, skin and cardiovascular health. However, there are few estimates of dietary Si intakes in man, especially in a UK population. Following the development of a UK food composition database for Si, the aim of the present study was to investigate dietary intakes of Si amongst healthy women aged over 60 years and to identify important food sources of Si in their diet. Healthy, post-menopausal female subjects (>60 years of age; n 209) were recruited from the general population around Dundee, Scotland as part of an unrelated randomised controlled intervention study where dietary intake was assessed using a self-administered, semi-quantitative food-frequency questionnaire at five time-points over a 2-year period. Food composition data on the Si content of UK foods was used to determine the Si content of food items on the food-frequency questionnaire. Mean Si intake was 18.6 (sd 4.6) mg and did not vary significantly across the 2 years of investigation. Cereals provided the greatest amount of Si in the diet (about 30 %), followed by fruit, beverages (hot, cold and alcoholic beverages combined) and vegetables; together these foods provided over 75 % about Si intake. Si intakes in the UK appear consistent with those reported previously for elderly women in Western populations, but lower than those reported for younger women or for men.

The silicon content of beer and its bioavailability in healthy volunteers.

Dietary Si, as soluble orthosilicic acid (OSA), may be important for the growth and development of bone and connective tissue. Beer appears to be a major contributor to Si intake, although the Si content of beer and its bioavailability in human subjects have not been well established. Here we investigated the Si content of different beers and then estimated Si absorption from beer in healthy volunteers. The Si content of seventy-six different beers was estimated using inductively coupled plasma optical emission spectrometry and one of the beers, used in the ingestion study, was ultrafiltered to determine OSA content. Next, following the ingestion of 0.6 litres beer (22.5 mg Si; 4.6 % (v/v) ethanol), serum and urinary Si levels were measured in nine healthy volunteers over a 6 h period. A solution of OSA was similarly investigated as a positive control and water and 4.6 % ethanol as negative controls. The mean Si level of beer was 19.2 (sd 6.6) mg/l; the median Si level was 18.0 mg/l. There was no significant difference in the Si levels of the different beers by geographical origin or type of beer. Serum and urinary Si levels increased considerably following the ingestion of beer or a solution of OSA but not with the ingestion of either 4.6 % ethanol or water. The ultrafilterability of Si from beer (about 80 %) and its absorption in volunteers (about 55 %) was comparable with that of a solution of OSA suggesting that Si in beer is present chiefly in a monomeric form and is readily bioavailable.

Dietary silicon intake is positively associated with bone mineral density in men and premenopausal women of the Framingham Offspring cohort.

The role of dietary silicon in bone health in humans is not known. In a cross-sectional, population-based study (2847 participants), associations between dietary silicon intake and BMD were investigated. Dietary silicon correlated positively and significantly with BMD at all hip sites in men and premenopausal women, but not in postmenopausal women, suggesting that increased silicon intake is associated with increased cortical BMD in these populations. Osteoporosis is a burgeoning health and economic issue. Agents that promote bone formation are widely sought. Animal and cellular data suggest that the orthosilicate anion (i.e., dietary silicon) is involved in bone formation. The intake of silicon (Si, approximately 30 mg/day) is among the highest for trace elements in humans, but its contribution to bone health is not known. In a cross-sectional, population-based study, we examined the association between silicon intake and bone mineral density (BMD) in 1251 men and 1596 pre- and postmenopausal women in the Framingham Offspring cohort (age, 30-87 years) at four hip sites and lumbar spine, adjusting for all potential confounding factors known to influence BMD and nutrient intake. Silicon intake correlated positively with adjusted BMD at four hip sites in men and premenopausal women, but not in postmenopausal women. No significant association was observed at the lumbar spine in any group. Categorical analysis by Si intake, or energy-adjusted Si intake, supported these findings, and showed large differences in BMD (up to 10%) between the highest (> 40 mg Si/day) and lowest (< 14 mg Si/day) quintiles of silicon intake. A significant association at the lumbar spine in men was also observed. Further analyses indicated that some of the effects seen for moderate consumption of alcoholic beverages on BMD might be attributed to Si intake. These findings suggest that higher dietary silicon intake in men and younger women may have salutary effects on skeletal health, especially cortical bone health, that has not been previously recognized. Confirmation of these results is being sought in a longitudinal study and by assessment of the influence of silicon intake on bone markers in this cohort.

Supplementation of calves with stabilized orthosilicic acid. Effect on the Si, Ca, Mg, and P concentrations in serum and the collagen concentration in skin and cartilage.

The bioavailability of silicon in stabilized orthosilicic acid was investigated in a double blind, placebo controlled supplementation study of calves maintained on a normal diet. The total dietary Si intake was increased by 4.9% in the form of stabilized orthosilicic acid. After 23 wk of Si supplementation, the serum Si concentration increased (p = 0.0001, n = 29) by 70% compared to control animals in spite of the low Si dose administered and the Si adequate diet. The individually administered Si dose was significantly associated with the serum Si concentration (r = 0.44, p = 0.016, n = 29). The collagen concentration in dermis was significantly higher (p = 0.019, n = 4) in the Si group and a positive correlation (r = 0.72, p = 0.018, n = 9) was found between the Si concentration in serum and the collagen concentration in cartilage. The calcium (Ca) and phosphorus (P) concentrations in serum were marginally higher for animals supplemented with Si compared to control animals. In serum, a significant linear relationship was found between the Si and the Ca concentration (r = 0.31, p = 0.019, n = 59), whereas the magnesium concentration correlated marginally with the Si concentration (r = 0.25, p = 0.068, n = 59). In summary, increasing the total dietary Si intake by 4.9% in the form of stabilized orthosilicic acid resulted in a 70% higher Si concentration in serum indicating a high bioavailability of Si in this supplement. The positive correlation between the serum Si concentration and the collagen concentration in cartilage and the serum Ca concentration, respectively, suggest the involvement of Si both in the formation of extracellular matrix components and in Ca metabolism.