Wintertime vitamin D insufficiency is common in young Canadian women, and their vitamin D intake does not prevent it.
OBJECTIVE
We asked whether women self-reporting the recommended consumption of vitamin D from milk and multivitamins would be less likely to have low wintertime 25-hydroxyvitamin D (25(OH)D) levels.


METHODS
This cross-sectional study enlisted at least 42 young women each month (age 18-35 y, 796 women total) through one year. We measured serum 25(OH)D and administered a lifestyle and diet questionnaire.


RESULTS
Over the whole year, prevalence of low 25(OH)D (<40 nmol/l) was higher in non-white, non-black subjects (25.6% of 82 women) than in the white women (14.8% of 702 white women, P<0.05). Of the 435 women tested during the winter half of the year (November-April), prevalence of low 25(OH)D was not affected by vitamin D intake: low 25(OH)D occurred in 21% of the 146 consuming no vitamin D, in 26% of the 140 reporting some vitamin D intake, up to 5 microg/day (median, 2.5 microg/day), and in 20% of the 149 women reporting vitamin D consumption over 5 microg/day (median, 10 microg/day).


CONCLUSIONS
The self-reported vitamin D intake from milk and/or multivitamins does not relate to prevention of low vitamin D nutritional status of young women in winter. Recommended vitamin D intakes are too small to prevent insufficiency. Vitamin D nutrition can only be assessed by measuring serum 25(OH)D concentration.
Vieth
R
R
Mount Sinai Hospital, Toronto, Canada. rvieth@mtsinai.on.ca
Cole
D E
DE
Hawker
G A
GA
Trang
H M
HM
Rubin
L A
LA
D000293:Adolescent; D000328:Adult; D002170:Canada / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D015596:Nutrition Assessment; D010024:Osteoporosis / Q000097:blood / Q000517:prevention & control*; D012621:Seasons; D012650:Self Disclosure; D014807:Vitamin D / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology* / Q000517:prevention & control
D014807:Vitamin D; C104450:25-hydroxyvitamin D