The evidencebehindthe increased NordicNutritionRecommendations for vitamind. Christel Lamberg-Allardt University of Helsinki

Transcription

1 The evidencebehindthe increased NordicNutritionRecommendations for vitamind Christel Lamberg-Allardt University of Helsinki

2 Aimsfor NutritionRecommendations

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4 Aimsfor vitamind The overall aim was to review recent scientific data on requirements and health effects of vitamin D and to report it to the NNR5 Working Group. The SLR followed the guidelines for conducting systematic reviews set by the Working group.

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6 The specific objectives of the review on health effects of vitamin D in human nutrition were to: 1) review the scientific evidence to determine, based on a set of agreed criteria, dietary reference values for vitamin D for different life stages (infants, children, adolescents, adults, elderly and during pregnancy and lactation) 2) assess the requirement for adequate growth, development and maintenance of health of vitamin D 3) assess the health effects of different intakes/exposures of vitamin D.

7 Lamberg-Allardt C, Brustad M, Meyer H, Steingrimsdottir L: Food Nutr Res Oct 3;57.

8 Expert group ( Laufey Steingrimsdottir; Haakon Meyer, Magritt Brustad; Christel Lamberg-Allardt behind the camera)

9 NNR 5 8 questions 1. What is the effect of vitamin D from different sources on serum 25(OH)D concentrations? 2. What is the relationship between 25(OH)D concentrations and different outcomes in different population and age groups? 3. What is the effect of dietary vitamin D intake on different outcomes in different population and age groups?

10 NNR 5 8 questions 4. What is the effect of supplemental vitamin D on different outcomes in differentpopulationand age groups? 5. What is the effect of sun or UVB exposure on different outcomes in different populatio and age groups? 6. What is the UL (Tolerable Upper Intake Level) for vitamin D for different health outcomesin different population and age groups?

11 NNR 5 8 questions 7. What are the interactions of vitamin D with calcium intake on different health outcomesin different population and age groups? 8. Which is the interaction of vitamin D intake or vitamin D status with vitamin A intake or vitamin A status on health outcomes in different population and age groups?

12 Material OnlypublishedSLRsand a fewnew RCTs Health outcomes: Pregnancyoutcomes and growth, Bone health (All fractures, Hip fractures, Vertebral fractures, Bonemineral density/ osteoporosis, Bone mass, Bone quality, Rickets, Osteomalacia, Dentalhealth); Muscle strength; Falls ; All cancers, Breast cancer; Colorectal cancer; Prostatecancer; Diabetes type I; Diabetes type II; Multiplesclerosis; Obesity; Total mortality; Hypertension/ blood pressure; Cardiovascular disease clinical outcomes; Infections

13 First search covering september 2010 Abstractsretrievedfromelectronic, bibliographic searches: 233 Inclusion criteria: SLR Second search covering May February Abstracts retrieved from electronic,bibliographic searches: 1473 Inclusion criteria: SLR, RCT Titles and abstract very unlikely to berelevant: 173 Titles and abstracts very unlikely to be relevant: 1425 Titles and abstracts that appeared potentially relevant, ordered as full text papers: 60 Full papers included: 22 Papers excluded: 38 Not a study question Nota SLR Old version(replaced) Withdrawn Papers excluded: 42 Not a study question Nota SLR Nota RCT Old version (replaced) Withdrawn RCT included in snowball SLR Low rating(d) Titles and abstracts that appeared potentially relevant, ordered as full text papers: 48 Full papers included: 6; 2 SLRs 4 RCTs Papers included(35) Snowballing March 2011 May 2012 : 7 SLRs Inclusion: SLR, RCT

14 Somelimitationsand confounding factors Intervention studies only in relation to bone UV-exposure not taken into account Season, clothing, time spent out of doors Basal 25(OH)D values are confounding e.g. earlier sunlight exposure, use of supplements

15 Somelimitationsand confounding factors Habitual intake mostly not taken into account Large differences in results depending on assay methods and laboratories measuring 25(OH)D, adding to the uncertainty of determining an appropriate target concentration. Compliance Overall heterogenity Doses, time, age

16 Results and conclusions: Health outcomes The SLR s we reviewed conclude that the evidence for a protective effect of vitamin D is only conclusive concerning bone health, total mortality and the risk of falling. The effect was often only seen in persons with low basal 25(OH)D concentrations. In addition, most intervention studies leading to these conclusions report that intervention with vitamin D combined with calciumand not vitamin D alone gives these benefits.

17 Results and conclusions: Optimal 25(OH)D concentration It was difficult to establish an optimal 25(OH)D concentration or vitamin D intake based on the SLRs, but there was evidence that a concentration of >50 nmol/l could be optimal.

18 Resultsandconclusions: How much vitamind? The dose-response studies relating vitamin D intake to 25(OH)D suggested that an intake of µg/d will increase the serum concentration by 1-2 nmol/l dependent on the basal concentration with response being greater when the basal concentration is low.

19 Resultsand conclusions: How muchvitamind? For those older than three years, a 50 nmol/l target for S- 25(OH)D concentration would probably require an average intake of 10 μg/d. Adding 2 SDs to this average intake would cover the 97.5% of the population. Given that 2SD equal 5μg/d, this would result in an intake of 15μg/d. These values are based on studies conducted in the winter without any sunlight exposure. Less is probably needed in the summer

20 Comments We referred to the total intake from food as well as supplements, given minimal sun exposure. Limited sunshine, however, does not reflect the situation for the majority of the Nordic population in the summertime. Moreover, the dose-response of vitamin D on serum 25(OH)D-concentrations is not well established and is dependent on the basal concentrations, sunshine exposure and dietary intake.

21 Upper Tolerable Level An Upper Tolerable Level was not possible to establish based on the SLRs. There is some concern that higher S-25(OH)D concentrations is associated with an increase in mortality.

22 The finalrecommendationfromnnr5

23 Principlesof NNR5 recommendations The NNR are based on the current nutritional conditions in the Nordic countries and are to be used as a basis for planning a diet that: satisfies the nutritional needs, i.e. covers the physiological requirements for normal metabolic functions and growth supports overall good health and contributes to a reduced risk of diet-associated diseases.

24 Principlesof NNR5 recommendations The NNR are valid for the average intake over a longer period of time of at least a week because the dietary composition varies from meal to meal and from day to day. The recommended intakes refer to the amounts of nutrients ingested, and losses during food preparation, cooking, etc. have to be taken into account when the values are used for planning diets.

25 Principlesof NNR5 recommendations The NNR can be used for a variety of purposes: as guidelines for dietary planning as a tool for assessment of dietary intake as a basis for food and nutrition policies as a basis for nutrition information and education as guiding values when developing food products

26 Reasoningbehindthe NNR5 vitamind recommendations Intervention studies with various doses of vitamin D show that an intake of 10 μg/d is needed to maintain serum 25OHD concentrations around 50 nmol/l among the majority of the population during wintertime at latitudes within the Nordic region. This RI considers some contribution of vitamin D from outdoor activities during the summer season(late spring to early autumn), and this is compatible with normal, everyday life.forpeople with little or no sun exposure, an intake of 20 μg/d is recommended.

27 Reasoningbehindthe NNR5 vitamin D recommendations For the elderly (>75 years of age), an intake of 20 μg/d is recommended, and this is mainly to account for the more limited solar-induced vitamin D synthesis and the evidence for the protective effect of such an intake against mortality, fractures, and falls.

28 Nordic vitamind recommendations NNR 5 (2012) < 2 yrs: 10 µg/d 3-74-yrs: 10 µg /d >75 yrs: 20 µg /d UL: yrs,adults 100 µg; 2-10-yrs 50 µg, 0-12 m 25 µg/ d ( accordingto IoM; EFSA)