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- Cashman, Kevin D., et al.
(författare)
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Individual participant data (IPD)-level meta-analysis of randomised controlled trials to estimate the vitamin D dietary requirements in dark-skinned individuals resident at high latitude
- 2022
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Ingår i: European Journal of Nutrition. - : Springer. - 1436-6207 .- 1436-6215. ; 61, s. 1015-1034
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Tidskriftsartikel (refereegranskat)abstract
- Context and purpose: There is an urgent need to develop vitamin D dietary recommendations for dark-skinned populations resident at high latitude. Using data from randomised controlled trials (RCTs) with vitamin D3-supplements/fortified foods, we undertook an individual participant data-level meta-regression (IPD) analysis of the response of wintertime serum 25-hydroxyvitamin (25(OH)D) to total vitamin D intake among dark-skinned children and adults residing at ≥ 40° N and derived dietary requirement values for vitamin D.Methods: IPD analysis using data from 677 dark-skinned participants (of Black or South Asian descent; ages 5–86 years) in 10 RCTs with vitamin D supplements/fortified foods identified via a systematic review and predefined eligibility criteria. Outcome measures were vitamin D intake estimates across a range of 25(OH)D thresholds.Results: To maintain serum 25(OH)D concentrations ≥ 25 and 30 nmol/L in 97.5% of individuals, 23.9 and 27.3 µg/day of vitamin D, respectively, were required among South Asian and 24.1 and 33.2 µg/day, respectively, among Black participants. Overall, our age-stratified intake estimates did not exceed age-specific Tolerable Upper Intake Levels for vitamin D. The vitamin D intake required by dark-skinned individuals to maintain 97.5% of winter 25(OH)D concentrations ≥ 50 nmol/L was 66.8 µg/day. This intake predicted that the upper 2.5% of individuals could potentially achieve serum 25(OH)D concentrations ≥ 158 nmol/L, which has been linked to potential adverse effects in older adults in supplementation studies.Conclusions: Our IPD-derived vitamin D intakes required to maintain 97.5% of winter 25(OH)D concentrations ≥ 25, 30 and 50 nmol/L are substantially higher than the equivalent estimates for White individuals. These requirement estimates are also higher than those currently recommended internationally by several agencies, which are based predominantly on data from Whites and derived from standard meta-regression based on aggregate data. Much more work is needed in dark-skinned populations both in the dose–response relationship and risk characterisation for health outcomes.
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- Fielding, R. A., et al.
(författare)
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Effect of structured physical activity and nutritional supplementation on physical function in mobility-limited older adults : Results from the VIVE2 randomized trial
- 2017
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Ingår i: The Journal of Nutrition, Health & Aging. - : Springer Science and Business Media LLC. - 1279-7707 .- 1760-4788. ; 21:9, s. 936-942
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Tidskriftsartikel (refereegranskat)abstract
- The interactions between nutritional supplementation and physical activity on changes in physical function among older adults remain unclear. The primary objective of this study was to examine the impact of nutritional supplementation plus structured physical activity on 400M walk capacity in mobility-limited older adults across two sites (Boston, USA and Stockholm, Sweden). All subjects participated in a physical activity program (3x/week for 24 weeks), involving walking, strength, balance, and flexibility exercises. Subjects were randomized to a daily nutritional supplement (150kcal, 20g whey protein, 800 IU vitamin D) or placebo (30kcal, non-nutritive). Participants were recruited from urban communities at 2 field centers in Boston MA USA and Stockholm SWE. Mobility-limited (Short Physical Performance Battery (SPPB) ae9) and vitamin D insufficient (serum 25(OH) D 9 - 24 ng/ml) older adults were recruited for this study. Primary outcome was gait speed assessed by the 400M walk. Results: 149 subjects were randomized into the study (mean age=77.5 +/- 5.4; female=46.3%; mean SPPB= 7.9 +/- 1.2; mean 25(OH)D=18.7 +/- 6.4 ng/ml). Adherence across supplement and placebo groups was similar (86% and 88%, respectively), and was also similar across groups for the physical activity intervention (75% and 72%, respectively). Both groups demonstrated an improvement in gait speed with no significant difference between those who received the nutritional supplement compared to the placebo (0.071 and 0.108 m/s, respectively (p=0.06)). Similar effects in physical function were observed using the SPPB. Serum 25(OH)D increased in supplemented group compared to placebo 7.4 ng/ml versus 1.3 ng/ml respectively. Results suggest improved gait speed following physical activity program with no further improvement with added nutritional supplementation.
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