Vitamin K content of Australian-grown horticultural commodities.

Vitamin K is a multi-function vitamin that has emerging roles in bone, brain and vascular health. Vitamin K composition data remain limited globally and Australia has lacked nationally representative data for vitamin K1 (phylloquinone) in horticultural commodities. Primary samples (n = 927) of 90 Australian-grown fruit, vegetable and nut commodities were purchased in three Australian cities. We measured vitamin K1/phylloquinone in duplicate in 95 composite samples using liquid chromatography with electrospray ionisation-tandem mass spectrometry. The greatest mean concentrations of vitamin K1/phylloquinone were found in kale (565 µg/100 g), baby spinach (255 µg/100 g) and Brussels sprouts (195 µg/100 g). The data contribute to the global collection of vitamin K food composition data. They add to the evidence that vitamin K1/phylloquinone concentrations vary markedly between geographic regions, supporting development of region-specific datasets for national food composition databases that do not yet contain data for vitamin K. Such data are needed globally.

Mapping the citation network on vitamin D research in Australia: a data-driven approach.

Vitamin D research can vary geographically, as vitamin D status is influenced by latitude, season, dietary intake, body mass index, ethnicity, and public health initiatives. Over the last two decades, research on vitamin D has increased in Australia, where the potential for sun exposure (a major source of vitamin D) is high. We aimed to identify key topics and gaps in vitamin D research in Australia using a data-driven approach. A literature search limited to Australian studies was conducted in the Web of Science Core Collection database. Citation network analysis was conducted to identify clusters and sub-clusters, depicted using word clouds. Topic analysis of each cluster and sub-cluster was conducted to identify topics and sub-topics, respectively. From 934 publications (over the period 1984-2022), nine topics and 60 sub-topics were identified. The nine topics were: vitamin D in vulnerable populations and its impact on child development; impact of sun exposure and ultraviolet-B radiation on various health conditions; vitamin D and falls and fractures in older adults; vitamin D and its association with health outcomes; vitamin D from sun exposure; testing of vitamin D status in Australia; vitamin D, calcium, and musculoskeletal health; vitamin D status and knee osteoarthritis; and vitamin D status and exercise performance in athletes. There were limited publications on vitamin D in Aboriginal and Torres Strait Islander peoples and dietary vitamin D. We have provided an overview of vitamin D research in Australia. The research trends and knowledge gaps identified can guide future research to better inform public health initiatives in Australia.

Effect of household cooking on the retention of vitamin D2 and 25-hydroxyvitamin D2 in pulse UV-irradiated, air-dried button mushrooms (Agaricus bisporus).

Vitamin D deficiency has widespread global prevalence. Fresh mushrooms exposed to ultraviolet (UV) radiation generate vitamin D2 which remains after drying. It is not clear if vitamin D2 is retained after rehydration and cooking of dried mushrooms. The aim of this study was to determine the true retention of both vitamin D2 and 25-hydroxyvitamin D2 (25(OH)D2) after cooking UV-irradiated, air-dried, then rehydrated button mushrooms (Agaricus bisporus). Mushrooms were exposed to pulsed UV radiation, then air-dried in a convection oven, followed by rehydration in warm water. Samples were cooked in three different ways: frying (5 min), baking (10 min, 200 °C) and boiling (20 min, 90 °C). Compared to rehydrated, uncooked controls, there was a high retention of D vitamers (≥95%) after cooking. Frying and baking resulted in significantly higher vitamin D2 retention compared to boiling (p < 0.0001). UV-irradiated, dried mushrooms are a valuable source of vitamin D2 after rehydration and cooking.

The Retention of Vitamin D2 and 25-Hydroxyvitamin D2 in Pulse UV-Irradiated Dried Button Mushrooms (Agaricus bisporus) after 12 Months of Storage.

Fresh mushrooms exposed to ultraviolet (UV) radiation prior to drying generate high concentrations of vitamin D2. The aim of this study was to determine the retention of D vitamers in mushrooms that were pulse UV irradiated, then air dried, and stored for up to 12 months. Fresh button mushrooms (A. bisporus) were exposed to pulsed UV radiation (dose 200 mJ/cm2, peak of 17.5 W/cm2), air dried and vacuum sealed before being stored in the dark at room temperature. After storage, samples were freeze dried and quantified for D vitamers using triple quadrupole mass spectrometry. After 3, 6 and 12 months of storage, there was 100% (11.0 ± 0.8 µg/g dry weight (DW), 93% (10.1 ± 0.6 µg/g DW) and 58% (5.5 ± 0.6 µg/g DW) retention of vitamin D2 and 88% (0.14 ± 0.01 µg/g DW), 71% (0.11 ± 0.01 µg/g DW) and 68% (0.1 ± 0.01 µg/g DW) retention of 25-hydroxyvitamin D2 (25(OH)D2), respectively. Compared to the irradiated dried mushrooms that were not stored, the D vitamer concentration was statistically significantly lower (p < 0.05) at 6 and 12 months for 25(OH)D2 and at 12 months for vitamin D2. Sufficient vitamin D2 (99 µg) remained after 12 months storage to provide at least 100% of daily dietary vitamin D requirements in a 20 g serving.

Vitamin D status in healthy populations worldwide: a systematic review protocol.

OBJECTIVE: The objective of this systematic review is to report on circulating concentrations of 25-hydroxyvitamin D (25[OH]D) and the prevalence of 25(OH)D concentrations below commonly used cut points for vitamin D deficiency, insufficiency, and sufficiency in healthy populations worldwide. INTRODUCTION: Vitamin D sufficiency is important for optimal bone health and has been identified as being protective against a range of adverse health outcomes. Poor vitamin D status is considered a global public health concern. This review will provide up-to-date data on 25(OH)D concentrations in healthy populations worldwide. INCLUSION CRITERIA: This review will consider data from publications that include measurements of circulating 25(OH)D concentrations in healthy people of all ages across all global geographical regions. METHODS: MEDLINE, Embase, Scopus, Web of Science, and Global Index Medicus will be searched for relevant studies published from March 1, 2011. Two reviewers will independently screen titles and abstracts using Research Screener, review relevant full-text articles for quality and eligibility, and extract data. Studies will, where possible, be pooled with statistical meta-analysis, while heterogeneity will be statistically tested. If relevant data are available, subgroup and sensitivity analyses will be conducted to investigate latitude, sex, age, season of blood collection, supplement use, 25(OH)D assay used (and whether it's certified to Reference Measurement Procedures developed under the Vitamin D Standardization Program), as well as study quality. REVIEW REGISTRATION: PROSPERO CRD42021242466.

Higher consumption of ultra-processed foods and increased likelihood of central nervous system demyelination in a case-control study of Australian adults.

BACKGROUND: Consumption of ultra-processed foods (UPFs) has been linked to risk of chronic diseases, with scant evidence in relation to multiple sclerosis (MS). METHODS: We tested associations between UPF consumption and likelihood of a first clinical diagnosis of central nervous system demyelination (FCD) (267 cases, 508 controls), a common precursor to MS. We used data from the 2003-2006 Ausimmune Study and logistic regression with full propensity score matching for age, sex, region of residence, education, smoking history, body mass index, physical activity, history of infectious mononucleosis, dietary misreporting, and total energy intake. RESULTS: Higher UPF consumption was statistically significantly associated with an increased likelihood of FCD (adjusted odds ratio = 1.08; 95% confidence interval = 1.0,1.15; p = 0.039), representing an 8% increase in likelihood of FCD per one energy-adjusted serving/day of UPFs. CONCLUSION: Higher intakes of UPF were associated with increased likelihood of FCD in this Australian cohort. Nutrition education and awareness of healthy eating patterns may benefit those at high risk of FCD.

Evidence of low vitamin D intakes in the Australian population points to a need for data-driven nutrition policy for improving population vitamin D status.

BACKGROUND: Nearly one in four Australian adults is vitamin D deficient (serum 25-hydroxyvitamin D concentrations [25(OH)D] < 50 nmol L-1 ) and current vitamin D intakes in the Australian population are unknown. Internationally, vitamin D intakes are commonly below recommendations, although estimates generally rely on food composition data that do not include 25(OH)D. We aimed to estimate usual vitamin D intakes in the Australian population. METHODS: Nationally representative food consumption data were collected for Australians aged ≥ 2 years (n = 12,153) as part of the cross-sectional 2011-2013 Australian Health Survey (AHS). New analytical vitamin D food composition data for vitamin D3 , 25(OH)D3 , vitamin D2 and 25(OH)D2 were mapped to foods and beverages that were commonly consumed by AHS participants. Usual vitamin D intakes (µg day-1 ) by sex and age group were estimated using the National Cancer Institute method. RESULTS: Assuming a 25(OH)D bioactivity factor of 1, mean daily intakes of vitamin D ranged between 1.84 and 3.25 µg day-1 . Compared to the estimated average requirement of 10 µg day-1 recommended by the Institute of Medicine, more than 95% of people had inadequate vitamin D intakes. We estimated that no participant exceeded the Institute of Medicine's Upper Level of Intake (63-100 µg day-1 , depending on age group). CONCLUSIONS: Usual vitamin D intakes in Australia are low. This evidence, paired with the high prevalence of vitamin D deficiency in Australia, suggests that data-driven nutrition policy is required to safely increase dietary intakes of vitamin D and improve vitamin D status at the population level.

Vitamin K content of cheese, yoghurt and meat products in Australia.

Vitamin K is vital for normal blood coagulation, and may influence bone, neurological and vascular health. Data on the vitamin K content of Australian foods are limited, preventing estimation of vitamin K intakes in the Australian population. We measured phylloquinone (PK) and menaquinone (MK) -4 to -10 in cheese, yoghurt and meat products (48 composite samples from 288 primary samples) by liquid chromatography with electrospray ionisation-tandem mass spectrometry. At least one K vitamer was found in every sample. The greatest mean (± standard deviation for foods sampled in multiple cities) concentrations of PK (4.9 µg/100 g), MK-4 (58 ± 9 µg/100 g) and MK-9 (8 ± 2 µg/100 g) were found in lamb liver, chicken leg meat and Cheddar cheese, respectively. Cheddar cheese (1.1 ± 0.3 µg/100 g) and cream cheese (1.0 µg/100 g) contained MK-5. MK-8 was found in Cheddar cheese only (4 ± 2 µg/100 g). As the K vitamer profile and concentrations appear to vary considerably by geographical location, Australia needs a vitamin K food composition dataset that is representative of foods consumed in Australia.

Total Dairy Consumption Is Not Associated With Likelihood of a First Clinical Diagnosis of Central Nervous System Demyelination.

Background: The evidence associating consumption of dairy products and risk of MS is contradictory and inconclusive. Objective: To test associations between dairy consumption and the likelihood of a first clinical diagnosis of central nervous system demyelination (FCD), a common precursor to MS. Methods: We used data from the 2003-2006 Ausimmune Study, a population-based Australian, multicentre, matched case-control study (272 cases, 519 controls). Total dairy consumption (servings/day) was calculated by summing consumption of milk, cheese and yogurt. Covariate-adjusted treatment effects using augmented inverse probability weighting was used to test for associations with FCD. We conducted sensitivity analyses in the subset of participants who had had a classic first demyelinating event (FDE), defined as a single, first episode of symptoms suggestive of CNS demyelination. Results: There were no statistically significant associations between total dairy consumption (per one serving/day) and FCD (adjusted OR 1.00; 95% CI 0.93, 1.07; p = 0.979). However, yogurt consumption (vs. no yogurt consumption) was associated with an 11% decreased likelihood of FDE (adjusted OR 0.89; 95% CI 0.89, 0.79; p = 0.046). Conclusion: While total dairy consumption was not associated with FCD in this Australian case-control study, yogurt consumption was associated with reduced likelihood of FDE.

Vitamin D Fortification of Milk Would Increase Vitamin D Intakes in the Australian Population, but a More Comprehensive Strategy Is Required.

Low vitamin D status (serum 25-hydroxyvitamin D (25(OH)D) concentration < 50 nmol/L) is prevalent in Australia, ranging between 15% and 32% in the adolescent and adult populations. Vitamin D intakes are also low across the population and were recently estimated at 1.8−3.2 µg/day on average, assuming equal bioactivity of the D vitamers. In combination, these findings strongly suggest that data-driven nutrition policy is needed to increase vitamin D intake and improve status in the Australian population. Food fortification is a potential strategy. We used up-to-date vitamin D food composition data for vitamin D3, 25(OH)D3, vitamin D2, and 25(OH)D2, and nationally representative food and supplement consumption data from the 2011−2013 Australian Health Survey, to model a fortification scenario of 0.8 µg/100 mL vitamin D for fluid dairy milks and alternatives. Under the modelled fortification scenario, the mean vitamin D intake increased by ~2 µg/day from baseline to 4.9 µg/day from food only (7.2 µg/day including supplements). Almost all individual intakes remained substantially below 10 µg/day, which is the Estimated Average Requirement in North America. In conclusion, this modelling showed that fortification of fluid milks/alternatives with vitamin D at the current permitted level would produce a meaningful increase in vitamin D intake, which could be of potential benefit to those with a low vitamin D status. However, this initial step would be insufficient to ensure that most of the population achieves the North American EAR for vitamin D intake. This approach could be included as an effective component of a more comprehensive strategy that includes vitamin D fortification of a range of foods.

Vitamin D composition of Australian game products.

The vitamin D content of many Australian game products is unknown. These foods are potential sources of vitamin D for remote-dwelling Aboriginal and Torres Strait Islander people, of whom 39% are vitamin D deficient (serum 25-hydroxyvitamin D3 (25(OH)D3) concentrations < 50 nmol/L). Vitamin D3, 25(OH)D3, vitamin D2 and 25(OH)D2 were measured by liquid chromatography-triple quadrupole mass spectrometry (LC-QQQ) in raw meat (camel, crocodile, emu, kangaroo), emu eggs and emu oil. Vitamin D3 (range, 0.5-14.5 µg/100 g) was found in all products except camel and kangaroo. All samples except kangaroo contained 25(OH)D3; some camel samples contained relatively high concentrations (range, 0.4-5.2 µg/100 g). Vitamin D2 was found in emu products and some kangaroo samples. We detected trace amounts of 25(OH)D2 in some camel and kangaroo samples. This study provides valuable insight into foods with a paucity of data on vitamin D content, showing that some are potentially useful sources of vitamin D.

A proinflammatory diet is associated with an increased likelihood of first clinical diagnosis of central nervous system demyelination in women.

BACKGROUND: While a number of studies have examined associations between dietary factors and risk of multiple sclerosis (MS), little is known about intakes of inflammation-modulating foods and nutrients and risk of MS. OBJECTIVES: To test associations between the Dietary Inflammatory Index (DII®) and risk of a first clinical diagnosis of central nervous system (CNS) demyelination (FCD) (267 cases, 507 controls) using data from the Ausimmune Study. METHODS: The 2003-2006 Ausimmune Study was a multicentre, matched, case-control study examining environmental risk factors for an FCD, a common precursor to MS. The DII is a well-recognised tool that categorises individuals' diets on a continuum from maximally anti-inflammatory to maximally pro-inflammatory. The DII score was calculated from dietary intake data collected using a food frequency questionnaire. Conditional logistic regression models were used to estimate the association between DII and FCD separately for men and women. RESULTS: In women, a higher DII score was associated with increased likelihood of FCD, with a 17% increase in likelihood of FCD per one-unit increase in DII score (adjusted odds ratio 1.17, 95% confidence interval 1.04-1.33). There was no association between DII and FCD in men (adjusted odds ratio 0.88, 95% confidence interval 0.73-1.07). CONCLUSIONS: These findings suggest that a pro-inflammatory diet is associated with an increased likelihood of FCD in women.

Vitamin D Food Fortification and Biofortification Increases Serum 25-Hydroxyvitamin D Concentrations in Adults and Children: An Updated and Extended Systematic Review and Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Low vitamin D status is a global public health issue that vitamin D food fortification and biofortification may help to alleviate. OBJECTIVES: We investigated the effect of vitamin D food fortification and biofortification on circulating 25-hydroxyvitamin D (25(OH)D) concentrations. We expanded the scope of earlier reviews to include adults and children, to evaluate effects by vitamin D vitamer, and investigate linear and nonlinear dose-response relations. METHODS: We conducted a systematic review and meta-analysis. We searched CINAHL, MEDLINE, PubMed, Embase, the Cochrane Library, and gray and unpublished literature sites for randomized controlled trials, including people of all ages, with the criteria: absence of illness affecting vitamin D absorption, duration ≥4 wk, equivalent placebo food control, dose quantification, dose ≥5 µg/d, baseline and endpoint or absolute change in 25(OH)D concentrations reported, random allocation, and participant blinding. Quality was assessed using the Jadad Scale. RESULTS: Data from 34 publications (2398 adults: 1345 intervention, 1053 controls; 1532 children: 970 intervention, 562 controls) were included. Random-effects meta-analysis of all studies combined (mean dose 16.2 µg/d) indicated a pooled treatment effect of 21.2 nmol/L (95% CI: 16.2, 26.2), with a greater effect for studies using cholecalciferol than ergocalciferol. Heterogeneity was high (I2  > 75%). Metaregression analyses for all studies combined suggested positive effect differences for baseline circulating 25(OH)D concentrations <50 nmol/L, dose ≥10 µg/d and a negative effect difference when the intervention arm included a calcium dose ≥500 mg/d greater than the control arm. Dose-response rates were found to be nonlinear (Wald test for nonlinearity P < 0.001). For all studies combined, a threshold occurred at ∼26 nmol/L for a dose of ∼21 µg/d. CONCLUSIONS: These results support use of vitamin D food fortification to improve circulating 25(OH)D circulations in populations. This work was registered with PROSPERO as CRD42020145497.

Vitamin D composition of Australian foods.

Australia needs accurate vitamin D food composition data to support public health initiatives. Previously, limitations in analytical methodology have precluded development of a comprehensive database. We used liquid chromatography with triple quadrupole mass spectrometry (LC-QQQ) to analyse 149 composite samples representing 98 foods (primary samples n = 896) in duplicate for vitamin D3, 25-hydroxyvitamin D3 (25(OH)D3), vitamin D2, 25(OH)D2. The greatest concentrations of vitamin D3 were found in canned salmon and a malted chocolate drink powder (fortified); chicken eggs and chicken leg meat contained the most 25(OH)D3. Margarine (fortified) and chocolate contained the greatest concentrations of vitamin D2, with smaller amounts found in various meat products. 25(OH)D2 was detected in various foods, including meats, and was quantitated in lamb liver. These data advance knowledge of dietary vitamin D in Australia and highlight the importance of analysis of these four forms of vitamin D to accurately represent the vitamin D content of food.

Prevalence and predictors of vitamin D deficiency in a nationally representative sample of Australian adolescents and young adults.

BACKGROUND/OBJECTIVES: Vitamin D deficiency is a public health concern worldwide. Maintaining vitamin D sufficiency during growth periods is essential. We aimed to determine the prevalence and predictors of vitamin D deficiency in Australian adolescents and young adults. SUBJECT/METHODS: We used data from adolescents (12-17 years, n = 692) and young adults (18-24 years, n = 400) who participated in the nationally representative 2011-2013 Australian Health Survey. Serum 25-hydroxyvitamin D concentrations were measured using a method certified to international standards, with prevalence reported for <50 (vitamin D deficiency), 50-<75, ≥75 and >125 nmol/L. Independent predictors of vitamin D deficiency were determined using a survey-weighted Poisson regression model. RESULTS: Overall, 17% of adolescents and 32% of young adults were vitamin D deficient. In models adjusted for sex, age, region of birth, socioeconomic status, BMI and season (and education, smoking status and physical activity in young adults only), the prevalence ratio (PR) for vitamin D deficiency was more than double in participants born outside Australia (adolescents: PR 2.46; 95% confidence interval (CI) = 1.59, 3.81; young adults: PR 2.12; 95% CI = 1.46, 3.07), and also varied by season (adolescents: spring vs summer PR 2.47; 95% CI = 1.22, 5.01 and winter vs summer PR 2.01; 95% CI = 1.03, 3.92; young adults: winter vs summer; PR 3.32; 95% CI = 1.69, 6.53). Other predictors of vitamin D deficiency were overweight compared with healthy weight (adolescents) and lower physical activity (young adults). CONCLUSIONS: Strategies based on safe sun exposure and dietary approaches are needed to achieve and maintain adequate vitamin D status, particularly in young adults.

Prevalence and predictors of vitamin D deficiency in a nationally representative sample of Australian Aboriginal and Torres Strait Islander adults.

Vitamin D deficiency (serum 25-hydroxyvitamin D (25(OH)D) concentration <50 nmol/l) is recognised as a public health problem globally. The present study details the prevalence and predictors of vitamin D deficiency in a nationally representative sample (n 3250) of Australian Aboriginal and Torres Strait Islander adults aged ≥18 years. We used data from the 2012-2013 Australian Aboriginal and Torres Strait Islander Health Survey (AATSIHS). Serum 25(OH)D concentrations were measured by liquid chromatography-tandem MS. Survey-weighted logistic regression models were used to determine the independent predictors of vitamin D deficiency. Approximately 27 % of adult AATSIHS participants were vitamin D deficient. Vitamin D deficiency was more prevalent in remote areas (39 %) than in non-remote areas (23 %). Independent predictors of vitamin D deficiency included assessment during winter (men, adjusted OR (aOR) 5·7; 95 % CI 2·2, 14·6; women, aOR 2·2; 95 % CI 1·3, 3·8) and spring (men, aOR 3·3; 95 % CI 1·4, 7·5; women, aOR 2·6; 95 % CI 1·5, 4·5) compared with summer, and obesity (men, aOR 2·6; 95 % CI 1·2, 5·4; women, aOR 4·3; 95 % CI 2·8, 6·8) compared with healthy weight. Statistically significant associations were evident for current smokers (men only, aOR 2·0; 95 % CI 1·2, 3·4), remote-dwelling women (aOR 2·0; 95 % CI 1·4, 2·9) and university-educated women (aOR 2·4; 95 % CI 1·2, 4·8). Given the high prevalence of vitamin D deficiency in this population, strategies to maintain adequate vitamin D status through safe sun exposure and dietary approaches are needed.

Efficacy of vitamin D food fortification and biofortification in children and adults: a systematic review protocol.

OBJECTIVE: The objective of this review is to assess the effect of vitamin D food fortification and biofortification on serum 25-hydroxyvitamin D (25(OH)D) concentrations. INTRODUCTION: Vitamin D deficiency is a global issue with considerable implications for public health. Many people do not receive sufficient sun exposure for adequate endogenous vitamin D synthesis, nor sufficient dietary vitamin D to meet their requirements. Increasing sun exposure may increase the risk of skin cancer, and vitamin D supplementation is not favored as a population-wide solution. Previous systematic reviews have shown a dose-dependent effect of vitamin D-fortified foods on circulating 25(OH)D concentrations. However, previous reviews did not investigate the efficacy of vitamin D fortification and biofortification in children, and several new fortification and biofortification trials in adults have been published since these earlier systematic reviews were conducted. INCLUSION CRITERIA: This review will consider randomized controlled trials that investigate the effect of vitamin D food fortification and biofortification on serum 25(OH)D concentrations in children and adults. METHODS: CINAHL, MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and PubMed will be searched for relevant studies published in English. Following a screening of titles and abstracts by a single author, relevant full-text articles will be independently reviewed by two authors. Two authors will independently assess methodological quality using the JBI critical appraisal checklist for randomized controlled trials. Data will be independently extracted by two authors. A meta-analysis will be conducted, and heterogeneity will be statistically tested. SYSTEMATIC REVIEW REGISTRATION NUMBER: PROSPERO CRD42020145497.

Iodine-containing food practices of Western Australian pregnant women and ethnicity: An observational study.

AIMS: The Australian Health Survey 2011 to 2013 indicated that Western Australian women had good iodine status, suggesting adequate consumption of iodine from food, however, little is known about pregnant women in this state. The aim was to investigate the iodine-containing food practices of Western Australian pregnant women. METHODS: Pregnant women attending antenatal clinics at a public tertiary hospital in Perth, Western Australia, were invited to complete a questionnaire investigating consumption of key iodine food sources and knowledge of iodine-containing foods. Food frequency data were entered into FoodWorks based on the Australian Food and Nutrition Database 2007. RESULTS: A total of 425 women took part in the study with a mean (SD) age of 29.4 (5.5) years. Sixty percent of women reported consuming bread at least daily. Only 37.6% of women used iodised salt, but the median (25, 75 percentile) iodine intake of these women was 183 (142, 267) µg/day compared to 148 (100, 228) µg/day of iodine from food only. Ethnicity was associated with iodised salt use: 76% of Asian women compared with 33% of Caucasian women. Three quarters of the women did not know if any foods are required to be fortified with iodine. CONCLUSION: The iodine-containing food practices of pregnant women in this state suggest a risk of insufficiency. The present study is limited by the use of a semi-quantitative and non-validated food frequency questionnaire, thus assessment of the iodine intake and status of pregnant women representative of the ethnic mix of Western Australia is recommended.

Prevalence and Predictors of Vitamin D Deficiency among African Immigrants Living in Australia.

Vitamin D deficiency (serum 25-hydroxyvitamin D (25(OH)D) concentrations <50 nmol/L) is a public health issue in Australia and internationally. Those with darker skin require a greater dose of ultraviolet B radiation from sunlight than those with paler skin to synthesise adequate amounts of vitamin D. Using data from the 2011-2013 Australian Health Survey, we investigated the prevalence and predictors of vitamin D deficiency in African immigrants aged ≥18 years living in Australia (n = 236). Serum 25(OH)D was measured using a liquid chromatography-tandem mass spectrometry method that is certified to international reference measurement procedures. Poisson regression was used to investigate independent predictors of vitamin D deficiency. A total of 36% of adults were vitamin D deficient (35% of men, 37% of women). The prevalence ratio (PR) of vitamin D deficiency decreased by 2% per year of age (PR 0.98; 95% CI (0.97, 0.99); p = 0.004) and was 1.6 times higher in those with low/sedentary, compared to moderate/high, physical activity levels (PR 1.64; 95% CI (1.12, 2.39); p = 0.011). The greatest risk was for those assessed during winter/spring compared with summer/autumn (PR 1.89; 95% CI (1.33, 2.64); p < 0.001). Culturally appropriate messaging on safe sun exposure and dietary vitamin D is warranted in order to promote vitamin D sufficiency in African immigrants living in Australia.

Prevalence and predictors of vitamin D deficiency in a nationally representative sample of adults participating in the 2011-2013 Australian Health Survey.

Vitamin D deficiency is recognised as a public health problem globally, and a high prevalence of deficiency has previously been reported in Australia. This study details the prevalence of vitamin D deficiency in a nationally representative sample of Australian adults aged ≥25 years, using an internationally standardised method to measure serum 25-hydroxyvitamin D (25(OH)D) concentrations and identifies demographic and lifestyle factors associated with vitamin D deficiency. We used data from the 2011-2013 Australian Health Survey (n 5034 with complete information on potential predictors and serum 25(OH)D concentrations). Serum 25(OH)D concentrations were measured by a liquid chromatography-tandem MS that is certified to the reference measurement procedures developed by the National Institute of Standards and Technology, Ghent University and the US Centers for Disease Control and Prevention. Vitamin D deficiency and insufficiency were defined as serum 25(OH)D concentrations <50 nmol/l and 50 to <75 nmol/l, respectively. Overall, 20 % of participants (19 % men; 21 % women) were classified as vitamin D deficient, with a further 43 % classified as insufficient (45 % men; 42 % women). Independent predictors of vitamin D deficiency included being born in a country other than Australia or the main English-speaking countries, residing in southern (higher latitude) states of Australia, being assessed during winter or spring, being obese, smoking (women only), having low physical activity levels and not taking vitamin D or Ca supplements. Given our increasingly indoor lifestyles, there is a need to develop and promote strategies to maintain adequate vitamin D status through safe sun exposure and dietary approaches.