Seasonal variation in 25(OH)D at Aberdeen (57°N) and bone health indicators -could holidays in the sun and cod liver oil supplements alleviate deficiency?
PLoS One. 2013;8(1):e53381. doi: 10.1371/journal.pone.0053381. Epub 2013 Jan 8.
Mavroeidi A, Aucott L, Black AJ, Fraser WD, Reid DM, Macdonald HM.
Musculoskeletal Research Programme, University of Aberdeen, Aberdeen, United Kingdom.
Vitamin D has been linked with many health outcomes. The aim of this longitudinal study, was to assess predictors of seasonal variation of 25-hydroxy-vitamin D ( 25(OH)D) (including use of supplements and holidays in sunny destinations) at a northerly latitude in the UK (57°N) in relation to bone health indicators. 365 healthy postmenopausal women (mean age 62.0 y (SD 1.4)) had 25(OH)D measurements by immunoassay, serum C-telopeptide (CTX), estimates of sunlight exposure (badges of polysulphone film), information regarding holidays in sunny destinations, and diet (from food diaries, including use of supplements such as cod liver oil (CLO)) at fixed 3-monthly intervals over 15 months (subject retention 88%) with an additional 25(OH)D assessment in spring 2008. Bone mineral density (BMD) at the lumbar spine (LS) and dual hip was measured in autumn 2006 and spring2007 (Lunar I-DXA). Deficiency prevalence (25(OH)D<25 nmol/L) was reduced in women who went on holiday to sunny destinations 3 months prior to their visit, compared to women who did not go on holidays [5.4% vs. 24.6% in Spring (p<0.001) and 3.8% vs. 25.6% in Winter (p = 0.001), respectively]. Similarly deficiency was lower amongst those who took CLO supplements compared to women that did not consume these supplements [2.0% vs. 23.7% in Spring (p = 0.001) and 4.5% vs. 24.8% in winter (p = 0.005), respectively]. There was no seasonal variation in CTX; 25(OH)D predicted a small proportion (1.8% variation) of LS BMD in spring 2007 [unstandardized β (SE): 0.039 (0.016), p = 0.017]. Seasonal variation of 25(OH)D had little effect on BMD and no effect on CTX. It appears that small increments in vitamin D (e.g. those that can be achieved by cod liver oil supplements of 5 µg/day) are sufficient to ensure that 25(OH)D is above 25 nmol/L for most people throughout the year. Similarly, holidays in sunny destinations show benefit.
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- >$1,000 annually for sunny vacation
With risk of skin damage from intense sun
- <$200 for UVB lamp to raise levels for many years
- <$40 for Vitamin D supplements and cofactors each year
- <$30 for Cod liver oil (but be careful of getting excess Vitamin A, which partially blocks vitamin D)
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- No – 10 minutes per day of sun-UVB is NOT enough
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- Vitamin D protects DNA against UV skin damage – 5 studies 2012-2013 need to add the vitamin D BEFORE going on a Suncation
- Search for "cod liver" on VitaminDWiki 537 hits July 2013
- Cod liver oil rarely has vitamin D from the liver or even from the cod
- Vitamin D, Cod-Liver Oil, Sunlight, and Rickets: A Historical Perspective – 2003
- Masterjohn on relationships between Vitamin A D and K – Dec 2010
- All items in category Vitamin A
- Increase your vitamin D from the sun by wearing a tan-through instead of standard shirt