November 19, 2004 – November, December and January are the months in which cases of seasonal depression are most frequent, north of the 40e parallel. Researchers in Toronto have discovered that an intake of vitamin D – or “sunshine vitamin” – would prevent this disease.
It is estimated that 3% to 6% of the Nordic adult population, the majority of whom are women, is affected by seasonal depression. This is mainly due to a vitamin D deficiency.
Researchers at the University of Toronto are trying to find out how the “sunshine vitamin” works to alleviate symptoms of seasonal depression. As part of a study1, they recruited 97 people who had a minimal level of vitamin D in the blood, while being highly likely to suffer from this discomfort.
For three months, they were given a vitamin D supplement3 (cholecalciferol). Participants in the first group took the equivalent of 600 international units (IU) per day of vitamin D in liquid form. Those in the second group took a dose of 4000 IU per day.
At the end of the experiment, in the winter of 2003, the researchers observed an improvement in psychological well-being in all participants. This improvement was significantly greater in those who took the highest doses of “sunshine vitamin”.
In light of these results, researchers argue that a dose of 4000 IU of vitamin D3 is well tolerated physically and is very safe.
Data from this study seem to corroborate those from a clinical trial2 also carried out in Canada and the results of which were published in 1998.
With its 44 participants, the experiment had shown that a daily supplementation of 400 IU or 800 IU of vitamin D had considerably reduced the symptoms of seasonal depression and this, over a period of only five days.
How to detect vitamin D deficiency?
People with little or no exposure to the sun are more likely to suffer from vitamin D deficiency. This late fall is a good time to have their vitamin D blood checked. hydroxycholecalciferol level. This should be at least 20 ng / L (nanograms3 per liter).
The contested Dr Michael Holick of Boston University, who has published more than 200 papers on this vitamin, argues that a good way to store vitamin D is to be in the sun for 10 to 20 minutes. two to three times a week during the summer. See our news on this.
Not all agree with this specialist, including associations of dermatologists. Also, if you prefer not to expose yourself to the sun, you can turn to supplements, or even integrate cod liver oil, salmon, mackerel or sardines canned in oil into your diet.
Martin LaSalle – PasseportSanté.net
According to WebMD
1. Vieth R, Kimball S, Hu A, Walfish PG, 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, Nutrition Journal, Jul 19, 2004, 3: 8.
2. Lansdowne AT, Provost SC, Vitamin D3 enhances mood in healthy subjects during winter, Psychopharmacology (BERL), February 1998, Vol. 135, No. 4, 319-23.
