The bioavailability of vitamin D from fortified cheeses and supplements is equivalent in adults

There is a need to increase the options for vitamin D fortification. We have developed a method to fortify hard cheese with vitamin D. Our aim was to characterize the bioavailability of vitamin D from fortified cheeses. Eighty adults were randomized to weekly servings of fortified cheddar cheese (DC) (34 g; n = 20); fortified low-fat cheese (DLF) (41 g; n = 10); liquid vitamin D supplement (1 mL), taken with food (DS+) (n = 20) or without food (DS-) (n = 10); placebo cheddar cheese (n = 10); or placebo supplement (n = 10). The treatments contained 28,000 IU cholecalciferol (vitamin D3), equivalent to 4000 IU (100 microg/d). The primary outcome was the comparison of vitamin D bioavailability, as measured by the serum 25-hydroxyvitamin D [25(OH)D] response, between fortified cheeses and supplement. In the placebo groups, initial 25(OH)D, 55.0 +/- 25.3 nmol/L, declined over the 8-wk winter protocol, to 50.7 +/- 24.2 nmol/L (P = 0.046). In the vitamin D-treated groups, the mean increases in 25(OH)D over 8 wk were: 65.3 +/- 24.1 (DC), 69.4 +/- 21.7 (DLF), 59.3 +/- 23.3 (DS+), and 59.3 +/- 19.6 nmol/L (DS-); these changes differed from the placebo groups (P < 0.0001) but not from one another (P = 0.62). Compared with baseline, serum parathyroid hormone decreased with both fortification (P = 0.003) and supplementation (P = 0.012). These data demonstrate that vitamin D is equally bioavailable from fortified hard cheeses and supplements, making cheese suitable for vitamin D fortification.     

Vitamin D-fortified milk achieves the targeted serum 25-hydroxyvitamin D concentration without affecting that of parathyroid hormone in New Zealand toddlers

For young children, the level of vitamin D required to ensure that most achieve targeted serum 25-hydroxyvitamin D [25(OH)D] ≥50 nmol/L has not been studied. We aimed to investigate the effect of vitamin D-fortified milk on serum 25(OH)D and parathyroid hormone (PTH) concentrations and to examine the dose-response relationship between vitamin D intake from study milks and serum 25(OH)D concentrations in healthy toddlers aged 12-20 mo living in Dunedin, New Zealand (latitude 46°S). Data from a 20-wk, partially blinded, randomized trial that investigated the effect of providing red meat or fortified toddler milk on the iron, zinc, iodine, and vitamin D status in young New Zealand children (n = 181; mean age 17 mo) were used. Adherence to the intervention was assessed by 7-d weighed diaries at wk 2, 7, 11, 15, and 19. Serum 25(OH)D concentration was measured at baseline and wk 20. Mean vitamin D intake provided by fortified milk was 3.7 μg/d (range, 0-10.4 μg/d). After 20 wk, serum 25(OH)D concentrations but not PTH were significantly different in the milk groups. The prevalence of having a serum 25(OH)D <50 nmol/L remained relatively unchanged at 43% in the meat group, whereas it significantly decreased to between 11 and 15% in those consuming fortified study milk. In New Zealand, vitamin D intake in young children is minimal. Our findings indicate that habitual consumption of vitamin D-fortified milk providing a mean intake of nearly 4 μg/d was effective in achieving adequate year-round serum 25(OH)D for most children.     

Fortification of orange juice with vitamin D: a novel approach for enhancing vitamin D nutritional health

BACKGROUND: Fortification of milk with vitamin D may not be adequate for satisfying the vitamin D requirement because of variability in vitamin D content after fortification and because many persons have milk allergy or lactose intolerance. Additional foods need to be fortified with vitamin D. OBJECTIVE: We determined whether vitamin D, a fat-soluble vitamin, is bioavailable in orange juice and skim milk, 2 nonfat beverages. DESIGN: On 3 separate occasions, 18 adults ingested 25 000 IU vitamin D(2) in 240 mL whole milk or skim milk or in 0.1 mL corn oil applied to toast. A separate, double-blind, randomized, controlled trial investigated whether the consumption of orange juice fortified with vitamin D(3) would increase serum 25-hydroxyvitamin D [25(OH)D] concentrations: 14 subjects ingested 240 mL orange juice fortified with 1000 IU vitamin D, and 12 subjects ingested a control orange juice daily for 12 wk. RESULTS: Peak serum vitamin D(2) concentrations did not differ significantly after the ingestion of vitamin D(2) in whole milk, skim milk, or corn oil on toast. After subjects consumed orange juice fortified with 1000 IU vitamin D(3) daily for 12 wk, serum 25(OH)D(3) concentrations increased by 150%, and serum parathyroid hormone concentrations decreased by 25% compared with baseline; control subjects had a seasonal increase of 45% in 25(OH)D and no significant change in serum parathyroid hormone. CONCLUSIONS: The fat content of milk does not affect vitamin D bioavailability. Vitamin D fortification at 1000 IU/240 mL orange juice for 12 wk safely increased 25(OH)D(3) concentrations in adults.     

Maintenance of wintertime vitamin D status with cholecalciferol supplementation is not associated with alterations in serum cytokine concentrations among apparently healthy younger or older adults

Epidemiological studies have shown that low vitamin D status results in impaired immune function and is associated with the prevalence of autoimmune and inflammatory conditions. Vitamin D supplementation has been shown to reduce circulating concentrations of inflammatory markers in such conditions. However, the possible beneficial effect of vitamin D supplementation in the general population, particularly for those individuals living at high latitudes where hypovitaminosis D is common during wintertime, remains unclear. The aim of this study was to assess the effect of vitamin D supplementation using doses of 5, 10, and 15 μg/d cholecalciferol (D3) compared with placebo on cytokine concentrations throughout winter in apparently healthy younger (aged 20-40 y) and older (aged ≥64 y) adults. A total of 211 younger and 202 older adults completed the 22-wk intervention (from October to March) with >85% compliance. Serum concentrations of 25-hydroxycholecalciferol [25(OH)D3], high sensitivity C-reactive protein, IL-6, IL-10, soluble CD40 ligand, TGFβ, TNFα, and fibrinogen were measured using ELISA. 25(OH)D3 concentrations significantly decreased in the placebo and 5 and 10/d μg D3 groups in the younger cohort and in the placebo group in the older cohort. Whereas 15 μg/d D3 supplementation maintained 25(OH)D3 concentrations in the younger cohort (baseline, 75.9 nmol/L; postintervention, 69.0 nmol/L) and significantly increased concentrations in the older cohort (baseline, 55.1 nmol/L; postintervention, 73.9 nmol/L), it had no significant effect on cytokine concentrations (ANCOVA, P > 0.05). The long-term effects of low vitamin D status remain to be elucidated and optimization of vitamin D status in otherwise healthy individuals may potentially have lasting beneficial effects on the immune system.     

Vitamin D deficiency: a worldwide problem with health consequences

Vitamin D deficiency is now recognized as a pandemic. The major cause of vitamin D deficiency is the lack of appreciation that sun exposure in moderation is the major source of vitamin D for most humans. Very few foods naturally contain vitamin D, and foods that are fortified with vitamin D are often inadequate to satisfy either a child's or an adult's vitamin D requirement. Vitamin D deficiency causes rickets in children and will precipitate and exacerbate osteopenia, osteoporosis, and fractures in adults. Vitamin D deficiency has been associated with increased risk of common cancers, autoimmune diseases, hypertension, and infectious diseases. A circulating level of 25-hydroxyvitamin D of >75 nmol/L, or 30 ng/mL, is required to maximize vitamin D's beneficial effects for health. In the absence of adequate sun exposure, at least 800-1000 IU vitamin D3/d may be needed to achieve this in children and adults. Vitamin D2 may be equally effective for maintaining circulating concentrations of 25-hydroxyvitamin D when given in physiologic concentrations.     

Moderate Amounts of Vitamin D3 in Supplements are Effective in Raising Serum 25-Hydroxyvitamin D from Low Baseline Levels in Adults: A Systematic Review

There is controversy surrounding the designation of vitamin D adequacy as defined by circulating levels of the metabolite 25-hydroxyvitamin D (25(OH)D). Depending on the cutoff level chosen, dietary intakes of vitamin D may or may not provide sufficient impact upon vitamin D status measured as improvement in serum levels of 25(OH)D. We sought to examine whether modest daily doses (5–20 μg) as found in fortified foods or multivitamin supplements had a measureable impact on vitamin D status, defined as moving from below to above 50 nmol/L, or from less than 30 nmol/L to above 30 nmol/L. Published literature was searched for relevant articles describing randomized controlled trials. Exclusion criteria were: studies not involving humans; review articles; studies lacking blood level data pre- and post-treatment; no control group; bolus treatments (weekly, monthly, yearly); vitamin D <5 μg or >20 μg; baseline 25(OH)D ≥75 nmol/L; subjects not defined as healthy; studies <8 weeks; and age <19 years. Of the 127 studies retrieved, 18 publications with 25 separate comparisons met criteria. The mean rate constant, defined as change in 25(OH)D in nmol/L per μg vitamin D administered, was calculated as 2.19 ± 0.97 nmol/L per μg. There was a significant negative correlation (r = −0.65, p = 0.0004) between rate constant and administered dose. To determine impact of the dose reflecting the Estimated Average Requirement (EAR) of 10 μg administered in nine studies (10 comparisons), in every case mean 25(OH)D status rose either from “insufficient” (30–50 nmol/L) to “sufficient” (>50 nmol/L) or from “deficient” (<30 nmol/L) to “insufficient” (>30 but <50 nmol/L). Our study shows that when baseline levels of groups were <75 nmol/L, for every microgram of vitamin D provided, 25(OH)D levels can be raised by 2 nmol/L; and further, when groups were deficient or insufficient in vitamin D, there was significant value in providing additional 10 μg per day of vitamin D.     

Effect of a voluntary food fortification policy on folate, related B vitamin status, and homocysteine in healthy adults

BACKGROUND: Mandatory folic acid fortification of food is effective in reducing neural tube defects and may even reduce stroke-related mortality, but it remains controversial because of concerns about potential adverse effects. Thus, it is virtually nonexistent in Europe, albeit many countries allow food fortification on a voluntary basis. OBJECTIVE: The objective of the study was to examine the effect of a voluntary but liberal food fortification policy on dietary intake and biomarker status of folate and other homocysteine-related B vitamins in a healthy population. DESIGN: The study was a cross-sectional study. From a convenience sample of 662 adults in Northern Ireland, those who provided a fasting blood sample and dietary intake data were examined (n = 441, aged 18-92 y). Intakes of both natural food folate and folic acid from fortified foods were estimated; we used the latter to categorize participants by fortified food intake. RESULTS: Fortified foods were associated with significantly higher dietary intakes and biomarker status of folate, vitamin B-12, vitamin B-6, and riboflavin than were unfortified foods. There was no difference in natural food folate intake (range: 179-197 microg/d) between the fortified food categories. Red blood cell folate concentrations were 387 nmol/L higher and plasma total homocysteine concentrations were 2 micromol/L lower in the group with the highest fortified food intake (median intake: 208 microg/d folic acid) than in the nonconsumers of fortified foods (0 microg/d folic acid). CONCLUSIONS: These results show that voluntary food fortification is associated with a substantial increase in dietary intake and biomarker status of folate and metabolically related B vitamins with potential beneficial effects on health. However, those who do not consume fortified foods regularly may have insufficient B vitamin status to achieve the known and potential health benefits.     

Ergocalciferol from mushrooms or supplements consumed with a standard meal increases 25-hydroxyergocalciferol but decreases 25-hydroxycholecalciferol in the serum of healthy adults

Few foods contain ergocalciferol or cholecalciferol. Treatment of mushrooms with UV light increases ergocalciferol content and could provide a dietary source of vitamin D. We evaluated the impact of consuming UV-treated white button mushrooms (Agaricus bisporus) on the vitamin D status of healthy adults. Thirty-eight volunteers were randomized to 4 treatments consumed with a standard meal for 6 wk: the control (C) group received untreated mushrooms providing 0.85 μg/d ergocalciferol (n = 10); groups M1 and M2 received UV-treated mushrooms providing 8.8 (n = 10) and 17.1 μg/d (n = 9), respectively; and the supplement (S) group received purified ergocalciferol plus untreated mushrooms, providing a total of 28.2 μg/d (n = 9). Serum total 25-hydroxyvitamin D [25(OH)D] and 25-hydroxyergocalciferol [25(OH)D2] were 83 ± 38 and 2.4 ± 2.0 nmol/L, respectively, at baseline (mean ± SD). At wk 6, 25(OH)D2 had increased and was higher in all treatment groups than in the C group, whereas 25-hydroxycholecalciferol [25(OH)D3] had decreased and was lower in the M2 and S groups than in the C group. Increases in 25(OH)D2 for groups C, M1, M2, and S were 1.2 ± 5.2, 13.8 ± 7.3, 12.7 ± 3.7, and 32.8 ± 3.3 nmol/L and decreases in 25(OH)D3 were -3.9 ± 16.3, -10.4 ± 6.4, -20.6 ± 14.6, and -29.5 ± 15.9 nmol/L, respectively. Concentrations did not change in group C. In summary, ergocalciferol was absorbed and metabolized to 25(OH)D2 but did not affect vitamin D status, because 25(OH)D3 decreased proportionally.     

Efficacy and safety of vitamin D3 intake exceeding the lowest observed adverse effect level

BACKGROUND: The Food and Nutrition Board of the National Academy of Sciences states that 95 microg vitamin D/d is the lowest observed adverse effect level (LOAEL). OBJECTIVE: Our objective was to assess the efficacy and safety of prolonged vitamin D3 intakes of 25 and 100 microg (1000 and 4000 IU)/d. Efficacy was based on the lowest serum 25-hydroxyvitamin D [25(OH)D] concentration achieved by subjects taking vitamin D3; potential toxicity was monitored by measuring serum calcium concentrations and by calculating urinary calcium-creatinine ratios. DESIGN: Healthy men and women (n = 61) aged 41 +/- 9 y (mean +/- SD) were randomly assigned to receive either 25 or 100 microg vitamin D3/d for 2-5 mo, starting between January and February. Serum 25(OH)D was measured by radioimmunoassay. RESULTS: Baseline serum 25(OH)D was 40.7 +/- 15.4 nmol/L (mean +/- SD). From 3 mo on, serum 25(OH)D plateaued at 68.7 +/- 16.9 nmol/L in the 25-microg/d group and at 96.4 +/- 14.6 nmol/L in the 100-microg/d group. Summertime serum 25(OH)D concentrations in 25 comparable subjects not taking vitamin D3 were 46.7 +/- 17.8 nmol/L. The minimum and maximum plateau serum 25(OH)D concentrations in subjects taking 25 and 100 microg vitamin D3/d were 40 and 100 nmol/L and 69 and 125 nmol/L, respectively. Serum calcium and urinary calcium excretion did not change significantly at either dosage during the study. CONCLUSIONS: The 100-microg/d dosage of vitamin D3 effectively increased 25(OH)D to high-normal concentrations in practically all adults and serum 25(OH)D remained within the physiologic range; therefore, we consider 100 microg vitamin D3/d to be a safe intake.     

Vitamin D Intake and Status in 12-Month-Old Infants at 63–66° N

The objective was to assess the vitamin D status in healthy 12-month-old infants in relation to quantity and sources of dietary vitamin D, breastfeeding and seasons. Subjects were 76 12-month-old infants. Serum levels of 25-hydroxyvitamin D (25(OH)D) ≥ 50 nmol/L were considered indicative of vitamin D sufficiency and 25(OH)D < 27.5 nmol/L as being indicative of increased risk for rickets. Additionally, 25(OH)D > 125 nmol/L was considered possibly adversely high. Total vitamin D at 9–12 months (eight data collection days) included intake from diet and supplements. The mean ± SD of vitamin D intake was 8.8 ± 5.2 μg/day and serum 25(OH)D 98.1 ± 32.2 nmol/L (range 39.3–165.5). Ninety-two percent of infants were vitamin D sufficient and none at increased risk for rickets. The 26% infants using fortified products and supplements never/irregularly or in small amounts had lower 25(OH)D (76.8 ± 27.1 nmol/L) than the 22% using fortified products (100.0 ± 31.4 nmol/L), 18% using supplements (104.6 ± 37.0 nmol/L) and 33% using both (110.3 ± 26.6 nmol/L). Five of six infants with 25(OH)D < 50 nmol/L had no intake of supplements or fortified products from 0 to 12 months. Supplement use increased the odds of 25(OH)D > 125 nmol/L. Breastfeeding and season did not affect vitamin D status. The majority of infants were vitamin D sufficient. Our findings highlight the need for vitamin D supplements or fortified products all year round, regardless of breastfeeding.     

Use of calcium, folate, and vitamin D₃-fortified milk for 6 months improves nutritional status but not bone mass or turnover, in a group of Australian aged care residents

In residential care, inadequate calcium and folate intakes and low serum vitamin D (25(OH)D) concentrations are common. We assessed whether daily provision of calcium, folate, and vitamin D?-fortified milk for 6 months improved nutritional status (serum micronutrients), bone quality (heel ultrasound), bone turnover markers (parathyroid hormone, C-terminal collagen I telopeptide, terminal propeptide of type I procollagen), and/or muscle strength and mobility in a group of Australian aged care residents. One hundred and seven residents completed the study (mean (SD) age: 79.9 (10.1) years; body weight: 68.4 (15.4) kg). The median (inter-quartile range) volume of fortified milk consumed was 160 (149) ml/day. At the end of the study, the median daily vitamin D intake increased to 10.4 (8.7) μg (P < .001), which is 70% of the adequate intake (15 μg); and calcium density (mg/MJ) was higher over the study period compared with baseline (161 ± 5 mg/MJ vs. 142 ± 4 mg/MJ, P < .001). Serum 25(OH)D concentrations increased by 23 ± 2 nmol/L (83 (107)%, P < .001), yet remained in the insufficient range (mean 45 ± 2 nmol/L). Consumption of greater than the median intake of milk (160 ml/day) (n = 54, 50%) increased serum 25(OH)D levels into the adequate range (53 ± 2 nmol/L) and reduced serum parathyroid hormone by 24% (P = .045). There was no effect on bone quality, bone turnover markers, muscle strength, or mobility. Consumption of fortified milk increased dietary vitamin D intake and raised serum 25(OH)D concentrations, but not to the level thought to reduce fracture risk. If calcium-fortified milk also was used in cooking and milk drinks, this approach could allow residents to achieve a dietary calcium intake close to recommended levels. A vitamin D supplement would be recommended to ensure adequate vitamin D status for all residents.     

Critique of the considerations for establishing the tolerable upper intake level for vitamin D: critical need for revision upwards

The tolerable upper intake level (UL) for vitamin D is 50 mcg/d (2000 iu/d) in North America and in Europe. In the United Kingdom a guidance level exists for vitamin D, 25 mcg/d (1000 iu/d), defined as the dose "of vitamins and minerals that potentially susceptible individuals could take daily on a life-long basis, without medical supervision in reasonable safety." Exposure of skin to sunshine can safely provide an adult with vitamin D in an amount equivalent to an oral dose of 250 mcg/d. The incremental consumption of 1 mcg/d of vitamin D3 raises serum 25-hydroxyvitamin D [25(OH)D ] by approximately 1 nmol/L (0.4 microg/L). Published reports suggest toxicity may occur with 25(OH)D concentrations beyond 500 nmol/L (200 microg/L). Older adults are advised to maintain serum 25(OH)D concentrations >75 nmol/L. The preceding numbers indicate that vitamin D3 intake at the UL raises 25(OH)D by approximately 50 nmol/L and that this may be more desirable than harmful. The past decade has produced separate North American, European, and U.K. reports that address UL or guidance-level values for vitamin D. Despite similar well-defined models for risk assessment, each report has failed to adapt its message to new evidence of no adverse effects at higher doses. Inappropriately low UL values, or guidance values, for vitamin D have hindered objective clinical research on vitamin D nutrition, they have hindered our understanding of its role in disease prevention, and restricted the amount of vitamin D in multivitamins and foods to doses too low to benefit public health.     

Bread fortified with cholecalciferol increases the serum 25-hydroxyvitamin D concentration in women as effectively as a cholecalciferol supplement

Fortification of foods is a feasible way of preventing low vitamin D status. Bread could be a suitable vehicle for fortification because it is a common part of diets worldwide. The bioavailability of cholecalciferol from bread is not known. We studied cholecalciferol stability, the concentration of the added cholecalciferol, the dispersion of cholecalciferol in bread, and the bioavailability of cholecalciferol from fortified bread. Three batches of fortified low-fiber wheat and high-fiber rye breads were baked; from each batch, 3 samples of dough and bread were analyzed for their cholecalciferol content. In a single-blind bioavailability study, 41 healthy women, 25-45 y old, with mean serum 25-hydroxyvitamin D concentration 29 nmol/L (range 12-45 nmol/L), were randomly assigned to 4 study groups. Each group consumed fortified wheat bread, fortified rye bread, regular wheat bread (control), or regular wheat bread and a cholecalciferol supplement (vitamin D control) daily for 3 wk. The daily dose of vitamin D was 10 mug in all groups except the control group. The vitamin dispersed evenly in the breads and was stable. Both fortified breads increased serum 25-hydroxyvitamin D concentration as effectively as the cholecalciferol supplement. Supplementation or fortification did not affect serum intact parathyroid hormone concentration or urinary calcium excretion. In conclusion, fortified bread is a safe and feasible way to improve vitamin D nutrition.     

Associations of diet, supplement use, and ultraviolet B radiation exposure with vitamin D status in Swedish women during winter

BACKGROUND: Vitamin D is produced endogenously after sun exposure but can also be obtained from natural food sources, food fortification, and dietary supplements. OBJECTIVE: We aimed to determine the vitamin D status of women (61-86 y old) living in central Sweden (latitude 60 degrees ) during winter and its relation with vitamin D intake and exposure to ultraviolet B radiation. DESIGN: In a cross-sectional study, we assessed the vitamin D status (serum 25-hydroxyvitamin D [25(OH)D]) of 116 women by using an enzyme immunoassay. The women completed questionnaires covering food habits, use of dietary supplements, and sun-related behavior. RESULTS: In a multiple linear regression model, the main determinants of serum 25(OH)D concentrations (x +/- SD: 69 +/- 23 mmol/L) were dietary vitamin D (6.0 +/- 1.8 mug/d), travel to a sunny location during winter within the previous 6 mo (26%), and the use of dietary supplements (16%). There was no association between serum 25(OH)D status during the winter and age, time spent outdoors, the use of sunscreen, or skin type. Serum 25(OH)D concentrations increased by 25.5 nmol/L with 2-3 servings (130 g/wk) fatty fish/wk, by 6.2 nmol/L with the daily intake of 300 g vitamin D-fortified reduced-fat dairy products, by 11.0 nmol/L with regular use of vitamin D supplements, and by 14.5 nmol/L with a sun vacation during winter. Among nonsupplement users without a wintertime sun vacation, 2-3 servings fatty fish/wk increased serum vitamin D concentrations by 45%. CONCLUSION: Fatty fish, vitamin D-fortified reduced-fat dairy products, regular supplement use, and taking a sun vacation are important predictors for serum concentrations of 25(OH)D during winter at a latitude of 60 degrees .     

Multinutrient-Fortified Juices Improve Vitamin D and Vitamin E Status in Children: A Randomized Controlled Trial

BackgroundProvision of fortified juices may provide a convenient method to maintain and increase blood fat-soluble vitamins.ObjectiveTo determine whether children consuming orange juice fortified with calcium and combinations of vitamins D, E, and A could increase serum 25-hydroxyvitamin D [25(OH)D], α-tocopherol, and retinol levels.DesignA 12-week randomized, double-blind, controlled trial.Participants/settingOne hundred eighty participants (aged 8.04±1.42 years) were recruited at Tufts (n=70) and Boston University (n=110) during 2005-2006. Of those recruited, 176 children were randomized into three groups: CaD (700 mg calcium+200 IU vitamin D), CaDEA (700 mg calcium+200 IU vitamin D+12 IU vitamin E+2,000 IU vitamin A as beta carotene), or Ca (700 mg calcium). Children consumed two 240-mL glasses of CaD, CaDEA, or Ca fortified orange juice daily for 12 weeks.Main outcome measuresSerum 25(OH)D, α-tocopherol, and retinol concentrations.Statistical analysesChanges in 25(OH)D, α-tocopherol, retinol, and parathyroid hormone concentrations were examined. Covariates included sex, age, race/ethnicity, body mass index, and baseline 25(OH)D, α-tocopherol, retinol, or parathyroid hormone levels. Multivariate models and repeated measures analysis of variance tested for group differences with pre–post measures (n=141).ResultsBaseline 25(OH)D was 68.4±27.7 nmol/L (27.4±11.10 ng/mL) ), with 21.7% of participants having inadequate 25(OH)D (<50 nmol/L [20.03 ng/mL]). The CaD group's 25(OH)D increase was greater than that of the Ca group (12.7 nmol/L [5.09 ng/mL], 95% CI 1.3 to 24.1; P=0.029). The CaDEA group's increase in α-tocopherol concentration was greater than that in the Ca or CaD groups (3.79 μmol/L [0.16 μg/mL], 95% CI 2.5 to 5.1 and 3.09 μmol/L [0.13 μg/mL], 95% CI −1.8 to 4.3), respectively (P<0.0001). Retinol levels did not change, and body weight remained as expected for growth.ConclusionsDaily consumption of orange juice providing 200 IU vitamin D and 12 IU vitamin E increased 25(OH)D and α-tocopherol concentrations in young children within 12 weeks.     

Prospective study on food fortification with vitamin D among adolescent females in Finland: minor effects

Vitamin D insufficiency is common particularly during winter time. After the recommendation by the Ministry of Social Affairs and Health, Finnish fluid milks and margarines have been fortified with vitamin D since February 2003. The aims of the present study were to examine the impact of vitamin D fortification of food supplies on serum 25-hydroxyvitamin D (S-25(OH)D) concentrations and on daily dietary vitamin D intake among adolescent females. One hundred and forty-two girls of Caucasian ethnicity aged 12-18 years completed semi-quantitative FFQ from which the dietary vitamin D and Ca intakes were calculated. S-25(OH)D was measured by radioimmunoassay. The study was performed from February-March 2000 to February-March 2004, one year after the initiation of fortification. The mean dietary intake of vitamin D was < 7.5 microg in 91.5 % of the adolescent girls in 2000 and 83.8 % in 2004. The midwinter mean S-25(OH)D concentration did not change significantly during the follow-up period (48.3 v. 48.1 nmol/l, NS). The proportion of participants who had S-25(OH)D concentration < 50 nmol/l was 60.6 % in 2000 and 65.5 % in 2004. Only 7.0 % of the participants had an adequate S-25(OH)D ( >or= 75 nmol/l) level in 2000 or 4 years later. The vitamin D fortification of fluid milks and margarines was inadequate to prevent vitamin D insufficiency. There are numerous adolescent girls and women who are not reached by the current fortification policy. Therefore new innovative and feasible ways of improving vitamin D nutrition are urged.     

Daily supplementation with 25 μg cholecalciferol does not increase calcium absorption or skeletal retention in adolescent girls with low serum 25-hydroxyvitamin D

In healthy adolescents, cross-sectional studies show either no or negative relationships between serum 25-hydroxyvitamin D [25(OH)D] and calcium (Ca) absorption. Using a 2-period metabolic balance study, the effect of vitamin D supplementation on Ca absorption and retention in adolescent girls was investigated. Eleven girls aged 12-14 y with a mean entry serum 25(OH)D of 35.1 nmol/L consumed a controlled intake (providing 5 μg vitamin D and 1117 mg Ca/d) for two 3-wk metabolic balance periods separated by a 1-wk washout period. Sunlight exposure was minimized by sunscreen with a sun protection factor ≥ 15. After the first metabolic balance period, participants received 25 μg/d cholecalciferol supplementation for 4 wk. Fractional Ca absorption was measured in each metabolic balance period using a stable Ca isotope method. All urine and fecal samples were collected and analyzed to measure net Ca absorption and Ca retention. Paired t tests and correlations were used to analyze the data. Daily supplementation with 25 μg vitamin D resulted in a mean increase in serum 25(OH)D of 13.3 nmol/L (P < 0.01) but a decrease in fractional Ca absorption of 8.3% (P < 0.05) and no significant change in fasting serum 1,25-dihydroxyvitamin D, parathyroid hormone, net Ca absorption, or Ca skeletal retention. In pubertal girls with vitamin D status considered insufficient in adults, vitamin D supplementation of 25 μg/d for 4 wk did not improve fractional Ca absorption, net Ca absorption, or Ca retention.     

Effects of vitamin D fortified milk on vitamin D status in Mongolian school age children

Mongolians are at high risk for vitamin D deficiency because of their residence at northern latitude, reduced exposure to UV-B rays during the winter months, and a low availability of vitamin-D fortified foods. We performed a pilot study in May 2005 to estimate the prevalence of hypovitaminosis D in Mongolian school age children and to determine the feasibility of conducting a longer and larger trial with fortified milk and vitamin D supplements. In a group of 46 Mongolian children (22 girls and 24 boys) aged 9-11 years, 76% (35) had levels of 25-hydroxyvitamin D (25(OH)D) below 50 nmol/L (20 ng/mL) and 32% had levels below 37 nmol/L (15 ng/mL). After a month of consuming 710 ml of vitamin D-fortified (total 300 IU or 7.5 microg) milk daily, only 3 of the children were below 50 nmol/L (20 ng/mL) and none below 37 nmol/L (15 ng/mL). These results reveal prevalent and serious 25(OH)D deficiency among Mongolian prepubertal school age children that appears to be ameliorated by a month of consuming approximately 7.5 microg of vitamin D3 in fortified milk.     

Vitamin D intake in Australian adults and the modeled effects of milk and breakfast cereal fortification

ObjectiveVitamin D intake from foods or supplements is a safe and attractive means to improve vitamin D status of populations. The aim of this study was to help identify population subgroups that would benefit most from efforts to increase intake. To do so, we investigated which personal characteristics are associated with vitamin D intake in an Australian population and modeled possible effects of expanded food fortification practices.MethodsWe investigated vitamin D intake in a population-based random sample of 785 adults, using a validated food frequency questionnaire, and assessed associations with personal and behavioral characteristics. We identified vitamin D food sources and modeled the hypothetical effects of blanket fortification of milk and breakfast cereals.ResultsAverage total vitamin D intake was 4.4 (±4.0) μg/g and below adequate intake for most participants in all age and sex subgroups. Higher intake was associated with being female, having a serious medical condition, energy intake below the median, and vitamin D supplement use (all P < 0.05). The “meat, fish, and eggs” food group contributed most to total vitamin D intake (51%), followed by dairy products and related foods (43%). If all milk and breakfast cereals were to be fortified with vitamin D, the average intake of vitamin D from foods would increase from 3.6 (±2.4) μg/d to 6.3 (±3.2) μg/d, with similar increases in all age and sex subgroups.ConclusionsVitamin D intake in Australia is generally below recommended levels, and few personal characteristics help to identify subgroups with low intake. Blanket vitamin D fortification of milk and breakfast cereals would substantially increase average vitamin D intake in Australian adults of all ages.     

Assessing the vitamin D status of the US population

This article describes the information currently available in the National Nutrition Monitoring System that is relevant to assessing the vitamin D status of US population groups, the strengths and limitations of this information, and selected results of vitamin D nutritional status assessments. The National Health and Nutrition Examination Survey (NHANES) provides information on vitamin D intakes only from 1988 to 1994. NHANES collected information on supplement use and circulating 25-hydroxyvitamin D [25(OH)D] concentrations from 1988 through current surveys. The National Nutrient Database for Standard Reference started providing limited data on the vitamin D content of foods in 2002 and continues to update these values. The Food Label and Package Survey provides 2006-2007 label information on vitamin D fortification of marketed foods. Despite limitations in the available data and controversies about appropriate criteria for evaluating vitamin D status among population groups, we can make some useful comparisons of vitamin D status among life-stage groups. In general, males have higher vitamin D intakes and 25(OH)D concentrations than do females. Children tend to have higher vitamin D status than adults. The increasing use of multivitamin-mineral dietary supplements in younger to older adults is not associated with a corresponding increase in serum 25(OH)D concentrations. In general, leaner individuals have higher circulating concentrations of 25(OH)D and supplement use than do heavier individuals. Finally, non-Hispanic whites tend to have higher vitamin D status than do non-Hispanic blacks and Mexican Americans.