Vitamin D security in northern Norway in relation to traditional sea food and UV-B light. Magritt Brustad1, Torkjel Sandanger1,2, Kåre Edvardsen2, and Ola Engelsen2 1Centrefor Sami Health Research, Institute of Community Medicine, University of Tromsø, Norway 2 Norwegian Institute for Air Research, The Polar Environment Centre, Tromsø, Norway. Vitamin D and health Vitamin D is essential for natural bone metabolism Calcium and phosphate regulation Vitamin D and bone health Skallelv, Finnmark, 1930 Vitamin D and health Cancer protective? Protect against autoimmune diseases? Sources of vitamin D Diet Fatty fish Cod liver oil Fortified butter and margarine The sun UVB-radiation The sun as vitamin D source Photoconvertion of pro- vitamin D in skin to vitamin D3 Activated in liver and kidneys Vitamin D3 from skin = vitamin D3 from diet Sun induced vitamin D Dependent on the sun ray’s qulaitative and quantitative properties Wave length Clouds Ozone thickness Surface reflection Sun angle – geography and season ”The Vitamin D winter” - UV-hours Sun induced vitamin D Individual level Skin type Sun exposure behaviour Clothes Use of sun tan cream/sunblock Time spent in the sun Clouds absorb the UVB-light Tromsø, 28 Juli 2006 Obtain vitamin D equal to 10 μg: - outdoor approx. 46 min with hands and face exposed (10% of the body) - outdoor approx. 16 min with 25 % of the body exposed Tromsø 22. July 2006 ~ 7 hours outdoor gives vitamin D equal to 10 μg Tromsø, 26 March 2006 Outdoor 17 min equivalent to 10 μg vitamin D Predictors for vitamin D status in northern Norway (n=300) Season Sun holiday and Solarium Mean: 25(OH)D: 66 vs. 53 nmol/l Vitamin D intakes (cod liver oil included) Subjects with 25(OH)D >37.5 nmol/l Mean intake = 6,8μg/d Subjects with 25(OH)D <37.5 nmol/l Mean intake = 3,2 μg/d Been in northern Norway the whole summer Mean 25(OH)D: 54 vs. 60 nmol/l Brustad et al. (2004) Public Health Nutr. 7:327-336 •Rickets prevelence = 60-70 % •Related to access to fish liver •Fish liver the main 1931 vitamin D source Proportion that consumed fish-liver 7 times or more/season, Troms county (Women and cancer study, 1998) Vitamin D and traditional sea food 90 80 70 utvalgene 60 50 Tromsø n=33 % av % 40 Skjervøy n=32 30 20 10 0 <37,5 nmol/l 37,5-50,0 >50 nmol/l nmol/l Utgangsverdier for plasma 25(OH)D 25(OH)D Fish liver – a traditional source of vitamin D Seasonal variation in 25(OH)D by fish liver consumption 60,00 50,00 25(OH)D nmol/l 40,00 fish liver 30,00 no fish liver 20,00 10,00 0,00 Oct Dec Feb April June Sept n=60, from a coastal community in northern Norway (Andenes) Brustad M, et al (2007) Photochemistry & Photobiology Sciences. 6, 903-8. One meal with ”mølje” provides (Cod, cod-liver and hard roe) : 12 recommended daily doses of vitamin D 11 recommended daily doses of vitamin A 1 recommended daily dose of vitamin E 14 g DHA + EPA 24 μg sum PCB Benefits and risks ÷ + High nutrient density Contaminants Health effects Social and cultural values Taste Knowledge Cost-saving Fish liver consumption and POPs POPs level in blood was not explained by fish liver intake in a coastal population in northern Norway (Skjervøy) (age and gender predicted POPs levels) Sandanger TM et al. (2006) J. Environ. Monit., 8, 552 - 557. Fish liver was an important source of vitamin D Brustad M et al. (2004) Publ. Health Nutr. 7(6), 783-789. Journal of Environmental Monitoring, 2007 Women and Cancer study n=(62076) Fish liver consumption was not associated with an increased cancer risk in breast, uterus, or colon 8 % decreased risk for total cancer was found. Conclusion The population in northern Norway depends on dietary sources of vitamin D Consumption of traditional sea food in northern Norway prevents vitamin D levels to drop considerably during winter and contributes to maintain good vitamin D status in the population.
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