Vieth R, Fraser D.
Vitamin D insufficiency: no recommended dietary allowance exists for this nutrient.
CMAJ. 2002 Jun 11;166(12):1541-2.
PMID: 12074121
In fact, current recommendations for vitamin D are not designed to ensure anything. They are simply based on the old, default strategy for setting a nutritional guideline, which is to recommend an amount of nutrient similar to what healthy people are eating. This approach underlies the circular logic behind a familiar refrain about nutrition: "If you eat a good diet, you won't need supplements." By this logic, the answer to the question, "How much nutrient do you need?" is, "Whatever healthy people happen to be eating." The essential point, lost in the confusing terminology of modern nutrient recommendations, is that a recommended daily allowance (RDA) does not yet exist for vitamin D. Instead, the recommendations for it are referred to as "adequate intake" (ai).12,13 The ai for young adults (5 µg or 200 IU) was chosen to approximate twice the average vitamin D intake reported by 52 young women in a questionnaire-based study reported from Omaha, Neb., in 1997.13,14 Because the available evidence was acknowledged as weak, the Food and Nutrition Board of the US Institute of Medicine called its recommendation an ai.
Vitamin D status in apparently healthy adults in Kashmir Valley of Indian subcontinent.
Zargar AH, Ahmad S, Masoodi SR, Wani AI, Bashir MI, Laway BA, Shah ZA.
Postgrad Med J. 2007 Nov;83(985):713-6.
PMID: 17989271
doi:10.1136/pgmj.2007.059113
Conclusions: In spite of abundant sunlight, healthy individuals in Kashmir valley are vitamin D deficient, particularly women. Serum 25 (OH) D concentrations are significantly related to sun exposure
Association between plasma 25-hydroxyvitamin D and breast cancer risk.
Crew KD, Gammon MD, Steck SE, Hershman DL, Cremers S, Dworakowski E, Shane E, Terry MB, Desai M, Teitelbaum SL, Neugut AI, Santella RM.
Cancer Prev Res (Phila Pa). 2009 Jun;2(6):598-604. Epub 2009 May 26.
PMID: 19470790
In summary, these results add to a growing body of evidence that adequate vitamin D stores may prevent breast cancer development. Whereas circulating 25-OHD levels of >32 ng/mL are associated with normal bone mineral metabolism, our data suggest that the optimal level for breast cancer prevention is ≥40 ng/mL. Well-designed clinical trials are urgently needed to determine whether vitamin D supplementation is effective for breast cancer chemoprevention.
Randomized comparison of the effects of the vitamin D3 adequate intake versus 100 mcg (4000 IU) per day on biochemical responses and the wellbeing of patients.
Vieth R, Kimball S, Hu A, Walfish PG.
Nutr J. 2004 Jul 19;3:8.
PMID: 15260882
doi:10.1186/1475-2891-3-8
CONCLUSION: The highest AI for vitamin D brought summertime 25(OH)D to >40 nmol/L, lowered PTH, and its use was associated with improved wellbeing. The 100 mcg/day dose produced greater responses. Since it was ethically necessary to provide a meaningful dose of vitamin D to these insufficient patients, we cannot rule out a placebo wellbeing response, particularly for those on the lower dose. This work confirms the safety and efficacy of both 15 and 100 mcg/day vitamin D3 in patients who needed additional vitamin D.
Towards an adequate intake of vitamin D. An advisory report of the Health Council of the Netherlands
R M Weggemans, G Schaafsma and D Kromhout
Eur J Clin Nutr advance online publication, July 22, 2009; doi:10.1038/ejcn.2009.67
Defining Adequate Vitamin D Intake : Cross-sectional and Intervention Studies
Viljakainen, Heli Tuulikki
University of Helsinki
2008-05-23
Doctoral dissertation (article-based)
Vitamin D is required for normal bone growth and maintenance of the skeleton throughout life. In Finland, like in many other Western countries, the population suffers from inadequate or deficient vitamin D status, especially during winter, which is thought to increase the risk of osteoporosis. New strategies to prevent osteoporosis are actively being sought. The main objective of this thesis was to determine whether vitamin D is feasible in the primary prevention of osteoporosis; does it affect bone mineral accrual during the growth period? A second goal was to ascertain whether seasonal variation in calcitropic hormones affects bone remodelling, and to elucidate the vitamin D intake needed to overcome this variation in different age groups.
In summary, vitamin D intake remains inadequate among the target groups of this thesis, as reflected by seasonal variation in calcitropic hormones and bone metabolism. Dietary intake of vitamin D should be increased to achieve at least an adequate vitamin D status (S-25-OHD>50 nmol/l) and possibly an optimal vitamin D status (S-25-OHD>80 nmol/l) throughout the year. This could be accomplished by introducing new vitamin D-fortified foods to the market."