Optimal vitamin D dosage for infants uncertain
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Editorial: Targeting Dietary Vitamin D Intakes and Plasma 25-Hydroxyvitamin D in Healthy Infants
Steven A. Abrams, M.D., of the Baylor College of Medicine, Houston, comments on the findings of this study in an accompanying editorial.
How long should we spend in the sun?
There isn’t one recommendation to suit everybody. This is because the amount of time you need to spend in the sun for your skin to make enough vitamin D depends on a number of things.
These include your skin type (for example, how dark your skin is or how easily you get sunburnt), the time of year and what time of day it is.
The amount of time you need to spend in the sun for your skin to make enough vitamin D is different for every person
Short daily periods of sun exposure without sunscreen during the summer months (April to October) are enough for most people to make enough vitamin D. Evidence suggests that the most effective time of day for vitamin D production is between 11am and 3pm.
A short period in the sun means a matter of minutes – about 10 to 15 minutes for most people – and is less than the time it takes you to start going red or to burn. The larger the area of your skin that is exposed to sunlight, the more chance there is of making enough vitamin D before you start to burn.
People with darker skin will need to spend longer in the sun to produce the same amount of vitamin D.
In the UK, our skin isn’t able to make vitamin D from winter sunlight (November to March) as the sunlight hasn’t got enough UVB (ultraviolet B) radiation. During the winter, we get vitamin D from our body’s stores and from food sources.
The longer you stay in the sun, especially for prolonged periods without sun protection, the greater the risk of skin cancer. So remember to cover up or protect your skin before the amount of time it takes you to start to turn red or burn later on. For most of the time you spend outside, stay covered up and use sunscreen with a sun protection factor (SPF) of at least 15. Find out more about keeping skin safe in the sun.
“The data reported by Gallo et al do not answer the question of what the target should be for plasma 25(OH)D concentration. If the target is 75 nmol/L or higher, then vitamin D intake of 400 IU/d is not enough for a substantial proportion of infants, especially those in northern parts of the United States or in Canada or who have darker skin pigmentation. … However, another question that needs to be answered is whether there are non-bone health reasons to target a plasma 25(OH)D concentration greater than 75 nmol/L. Answering such questions about non-bone health aspects of vitamin D nutrition can be accomplished only by rigorous clinical trials that include enough participants and establish clear outcomes before the study begins.”
“Pending such information, clinicians can be reassured by the findings from the study by Gallo et al that a daily vitamin D intake of 400 IU/d in infants, as currently recommended, leads to adequate plasma 25(OH)D concentration for identified physiological functioning related to bone health.”
Editor’s Note: Please see the article for additional information, including financial disclosures, funding and support, etc.
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Hope Weiler
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