April 13, 2007 – People living in the northern hemisphere of the globe suffer from such a marked deficiency in vitamin D that their daily intake should be revised upwards. This is supported by fifteen scientists specializing in the question, including the renowned American doctor Walter C. Willett.
All these experts jointly published an editorial1 in L’American Journal of Clinical Nutrition. They believe it is time for doctors and patients to lobby policy makers so that people living in northern latitudes can experience the true health benefits of vitamin D.
In the background of this editorial, a study2 recently published in the same journal whose results show that the British suffer from “an alarming deficiency” in vitamin D. Indeed, 60% of the 7,400 people who took part in the study showed a concentration of vitamin D less of 75 nmol / l of blood, on an annual basis. In autumn and winter, this proportion reaches 87%, or almost nine out of ten people!
However, for it to be effective in protecting the density of bone mass or reducing the risk of fractures, the blood concentration of vitamin D must be 75 nmol / l or more, say the co-signers.
In Canada, vitamin D deficiency varies by region. However, it would be lower than in Great Britain where legislation does not allow the addition of vitamin D to milk.
Conclusive results
According to these scientists, sufficient intakes3 daily are not currently high enough to reach this threshold of 75 nmol / l.
“Clinical trials that have been successful have used daily doses of 700 IU to 800 IU of vitamin D – with or without calcium supplement,” they say.
They therefore estimate that the scientific results on the subject militate in favor of vitamin D supplementation of 800 IU per day for populations living in northern latitudes. This contribution would offer increased protection against fractures “and even potentially against colon cancer”, they note.
In people aged 70, for whom the sufficient intake has been established at 600 IU per day, experts suggest raising this threshold to 1000 IU daily. They point out that humans can safely tolerate up to 10,000 IU per day.
For more information, see the Vitamin D sheet and the Vitamin D Nutrient List.
Martin LaSalle – PasseportSanté.net
1. Vieth R, Bischoff-Ferrari H, et al. The urgent need to recommend an intake of vitamin D that is effective, American Journal of Clinical Nutrition, March 2007, Vol. 85, No 3, 649-50.
2. Hypponen E, Power C, Hypovitaminosis D in British adults at age 45 y: nationwide cohort study of dietary and lifestyle predictors, American Journal of Clinical Nutrition, March 2007, Vol. 85, No 3, 860-8.a1.
3. In the absence of sufficient scientific data, the authorities have set, not a recommended nutritional intake (RDA), but a sufficient intake (AS). Adequate Intake is a Recommended Average Daily Intake based on the Average Intakes in healthy North Americans.
