Updated: Aug 23, 2019
Vitamin D - sunshine in a bottle
The well known function of vitamin D is to regulate calcium in the body, having a major effect on bone mineralisation, and general bone and muscle health. Vitamin D is also emerging as a major vitamin in disease prevention, regulating inflammation and healthy immunity.
If you have been suffering from ongoing colds and reoccurring infections this winter, its a possibility that you have low vitamin D levels. Low vitamin D levels have been associated with increased autoimmunity and an increased incidence of infection. Vitamin D also appears to be important protection against viral and bacterial upper respiratory tract infections.
Although Vitamin D is not easy to obtain from the diet of which oily fish (mackerel, sardines, herrings, cod, salmon), mushrooms, and eggs are sources. Only 5% - 10% comes from food, minor in comparison to the 90% obtained from sunlight.
10 % from food compared to 90 % from sunlight
Vitamin D is synthesised in your skin from UVB rays becoming a metabolically active hormone following its stimulation from the liver and kidneys. It then goes to work attaching to any of the 200+ receptors throughout the body.
While we are all very conscious about the hazardous effects of the suns rays, a little bit of sunshine is excellent for health. After all it was once thought of as the giver of life before it was an enemy.
So are you getting enough sunshine?
Healthy sun exposure is about short sharp bursts in the sun with as much skin exposure as you can. Full legs and arms, full torso, or naked if possible. Staying for 5- 15 minutes in summer, 25-45 in winter, 2 -3 times per week, getting out just before you turn pink.
Those at risk of Vitamin D deficiency
housebound or institutionalised
people with fat malabsorbtion conditions
liver or kidney conditions and inflammatory bowel disease
dark pigmented skin who receive very little direct sunlight
breastfeed infants whose mothers are at risk of deficiency
ageing - as this lowers the capacity for production
Testing for Vitamin D
Vitamin D levels are checked via a 25-hydroxy vitamin D blood test. The optimum range for whole body health is 75 to 120 nmol/L
< 25 nmol/L Moderate to severe deficiency
25-50 nmol/L Mild deficiency/insufficiency
50-150 nmol/L Optimal target range for bone health
>250 nmol/L Associations with adverse effects
Getting your vitamin D levels checked at the end of winter to see how you fair up? Did you make enough to see you throughout or do you need to adjust your relationship with sun exposure. For some this may mean supplementing of which 800-1000 IU is a general dose, but this will depend on your health and where in the world you live as latitude effects sunlight exposure.
Here in New Zealand 32% of people are below the recommended blood level, and with the growing evidence on vitamin D function in immune health - having a 10 minute break in the sun sleeves rolled up, shoes off is an excellent option for better health.